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Coronary Sinus Lead Implantation


Introduction

Cardiac resynchronization therapy (CRT) reduces hospitalization, improves quality of life, and lowers mortality in selected patients with congestive heart failure (CHF). CRT requires left ventricular (LV) pacing, usually via a lead placed transvenously through a coronary vein on the epicardium. Transvenous pacing of the LV epicardium via the coronary venous system can be technically difficult but is safe, and stimulation thresholds remain stable. Transvenous LV lead implantation was new in 1998. As with most new therapeutic procedures, it required the development of tools and techniques to safely and cost effectively implement this new therapy into clinical practice. CRT devices are implanted predominantly by cardiac electrophysiologists employing new skills borrowed from interventional cardiologists and radiologists. In addition, the manufacturers of cardiac implantable electronic devices (CEIDs) have benefited from the technical improvisation of many implanting physicians and the recruitment of new product manufacturers who have provided innovative solutions to coronary venous lead implantation.

Case Study 30-1
Left Ventricular Lead Implantation in an Unusual Anatomy of the Proximal Coronary Sinus *

* Reprinted with kind permission from Springer Science+Business Media: J Interv Card Electrophysiol 18(2):191-193, 2007.

Abstract

A 62-year-old man with class III heart failure and left bundle branch block underwent cardiac resynchronization therapy. Because prior implantation attempts from the left side were unsuccessful, the right side approach was attempted. However, it was still impossible to advance the preshaped sheaths into the distal coronary sinus (CS) because the CS was abnormal with a posterior vertical takeoff followed by a sharp sigmoid curve before the atrioventricular (AV) groove. Ultimately, a straight sheath was adjusted to fit the sigmoid curve with the guidance of an electrophysiologic catheter and a left ventricular (LV) lead was then passed into the anterolateral vein.

Introduction

In cardiac resynchronization therapy (CRT), the implantation of the LV lead is sometimes limited by the CS anatomy, not only the distal branching pattern but also the course of the proximal portion. 1 , 2 We report a successful implantation of an LV lead in the CS with an unusual take off and proximal course and suggest one strategy to solve the problem.

Case Report

Implantation of a CRT device with a defibrillator (CRT-D) was requested for a 62-year-old man with ischemic cardiomyopathy, LV ejection fraction of 20%, New York Heart Association (NYHA) class III heart failure and left bundle branch block. Because prior attempts to implant an LV lead from the left side had been unsuccessful at other institutions, he previously had two prior implantations of a defibrillator alone. On a prior attempt to upgrade the device to a CRT-D device at our institution, he had also been found to have an occlusion of the left subclavian and innominate veins. Therefore it was decided to upgrade the device to a CRT-D device from the right side. The right subclavian vein was punctured and cannulation of the CS was attempted using a hexapolar electrophysiologic catheter via a 13-French sheath. However, it was impossible to advance the catheter into the distal CS because the proximal portion of the CS was found to be quite abnormal with a posterior vertical take off followed by a sharp sigmoid curve before reaching the AV groove ( Fig. E30-1A ). Attempts to pass a right-sided sheath and then a multipurpose sheath were unsuccessful. Though cannulation of the midcardiac vein was attempted, a diverticulum instead of that vein was found at the sigmoid curve of the CS (see Fig. E30-1A ). Ultimately, an 8-French straight sheath (Rapido CS-ST, Guidant, St. Paul, MN) could be adjusted to the sigmoid curve of the CS with the guidance of a hexapolar electrophysiologic catheter and the tip of the sheath could be advanced to just before the end of the sigmoid curve (see Fig. E30-1A ). An LV lead (EASYTRAK 2, Guidant, St. Paul, MN) was then passed into the AV groove portion of the CS. Because the CS-graphy could not reveal the anatomy of the distal CS, selection of the CS branches with a guidewire was attempted. Though the selection of the anterolateral vein with a guidewire was successful, the LV lead could not be passed into the vein because of the lack of backup force from the sheath. Finally, the LV lead was placed in the anterior position (see Figs. E30-1B, C and E30-2 ). At that site, the initial Rwave was approximately 6 mV, the unipolar threshold was 1.2 V, and bipolar threshold 2.7 V. Following that, right atrial and right ventricular defibrillator leads were appropriately implanted. Defibrillation testing was successful at 14 J, and the patient experienced no complications from the procedure and had no hospitalizations due to heart failure for up to 6 months of follow-up. At the 6-month follow-up, a decrease in the NYHA functional class (from III to II) and level of the brain natriuretic peptide (from 784 to 253 pg/mL), and an improvement in the echocardiographic LV ejection fraction (from 20% to 27%) were observed.

Figure E30-1, A, A venogram of the coronary sinus (CS). The arrowheads indicate a diverticulum. B and C, A left ventricular lead implantation through a straight sheath adjusted to the sigmoid curve of the CS. A and B, Left anterior oblique views. C, Right anterior oblique view.

Figure E30-2, Chest x-ray images ( Left; anteroposterior view, Right; lateral view). LV, Left ventricular lead; RV, right ventricular lead.

Discussion

The implantation of an LV lead is often more difficult from the right side than from the left side. However, the right side approach may be recommended in cases like ours with a CS with a posterior vertical takeoff because pushability of the sheath coaxial to the CS was possible. A straight sheath rather than a preshaped sheath can be useful in cases like ours with a sharp sigmoid curve of the CS prior to the AV groove because the former one may be adjusted more appropriately than the latter one with the guidance of an electrophysiologic catheter.

Preimplantation knowledge of the anatomy of the CS and its tributaries using noninvasive three-dimensional imaging such as multislice computed tomography or magnetic resonance imaging may help to decide the feasibility and strategy of the transvenous LV lead placement for CRT. 3 , 4 If the transvenous LV lead placement is expected to be difficult or not effective in improving the LV function, an epicardial LV lead implantation should be considered as an alternative implantation technique despite the relatively high risk of complications. Though three-dimensional imaging may not be necessary in every patient, that may be recommended especially in patients with a prior failure of an LV lead placement like ours.

References

  • 1.

    Daoud EG, Kalbfleisch SJ, Hummel JD, et al: Implantation techniques and chronic lead parameters of biventricular pacing dual-chamber defibrillators. J Cardiovasc Electrophysiol 13:964–970, 2002.

  • 2.

    De Martino G, Sanna T, Dello Russo A, et al: A randomized comparison of alternative techniques to achieve coronary sinus cannulation during biventricular implantation procedures. J Interv Card Electrophysiol 10:227–230, 2004.

  • 3.

    Jongbloed MR, Lamb HJ, Bax JJ, et al: Noninvasive visualization of the cardiac venous system using multislice computed tomography. J Am Coll Cardiol 45:749–753, 2005.

  • 4.

    Wijetunga M, Cuoco F, Ravi ND, et al: Characterization of the coronary sinus ostium by cardiac magnetic resonance imaging. Am J Cardiol 98:1400–1402, 2006.

Case Study 30-2
Duplicated Coronary Sinus with a Connecting Branch *

* From Europace 10(7):880-881, 2008. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. © The Author, 2008.

A 48-year-old woman with class III heart failure and left bundle branch block underwent an implantation for cardiac resynchronization therapy. Right anterior oblique (RAO) view coronary sinus (CS) venography suggested the anterolateral and posterolateral branches appeared to arise from the same vessel of a duplicated CS, but the anterolateral branch arising from a different vessel was visualized via a connecting branch by the contrast injected into the vessel with the posterolateral branch, and the distal parts of the two vessels were superimposed in the RAO view. This unusual anomaly may have the potential risk for complications such as perforations.

Implantation of a cardiac resynchronization therapy (CRT) device with a defibrillator was recommended for a 48-year-old woman with ischemic cardiomyopathy, a left ventricular (LV) ejection fraction of 25%, New York Heart Association class III heart failure, and left bundle branch block. She had undergone coronary bypass surgery and mitral valvoplasty. In a balloon-occluded CS venogram in the RAO view, the anterolateral (solid star) and posterolateral (open star) branches appeared to arise from the same vessel in the venography, but a duplicated CS (white arrowheads) with a connecting branch was suggested in the late phase ( Fig. E30-3A and B ). During the implantation of the LV lead, the anterolateral branch was considered as a preferable choice of the target vein because the posterolateral branch had an acute take off and small lumen. However, the guidewire could not be advanced to the target site. A balloon-occluded CS venogram was then performed in the left anterior oblique view and revealed that a branch (dotted arrows) connected the two vessels and the anterolateral and posterolateral branches arose from different vessels (see Fig. E30-3D ). When the balloon was deflated during the contrast injection, a simultaneous visualization of the proximal portions of the two vessels was achieved and it revealed that the two vessels had a common ostium (black arrowheads) (see Fig. E30-3E ). Cannulation into the vessel with the anterolateral branch was not feasible because of the acute takeoff of the vessel. Ultimately, the LV lead was successfully implanted into the posterolateral branch (see Fig. E30-3C and F ).

Figure E30-3, Coronary sinus venograms ( A, B, D, and E ) and left ventricular lead positions ( C and F ). A, Early phase; B, late phase; D, with the balloon occlusion; and E, without the balloon occlusion. The solid and open stars indicate the anterolateral and posterolateral branches, respectively, white arrowheads a duplicated coronary sinus, dotted arrows a connecting branch, and black arrowheads a common ostium.

The anatomy of the CS has become a subject of more interest because the implantation of the LV leads into the CS has been widely employed in the CRT. Noninvasive three-dimensional imaging, such as multislice computed tomography or magnetic resonance imaging, has revealed that the CS and its tributaries have anatomical variations. 1 , 2 Nevertheless, anomalies of the CS anatomy may sometimes complicate the implantation of the LV lead. 3 Coronary sinus venography is very helpful to recognize the CS anatomy and to decide about the optimal strategy of the LV lead implantation. In this case, the anterolateral and posterolateral branches appeared to arise from the same vessel of the duplicated CS, but a different vessel with the anterolateral branch was visualized via a connecting branch by the contrast injected into the vessel with the posterolateral branch, and the distal parts of the two vessels were superimposed in the RAO view. This unusual anomaly may have a potential risk of complications such as a perforation when the LV lead is forced towards the anterolateral branch via the vessel with the posterolateral branch. In fact, some doctors prefer single plane to simultaneous biplane angiography for an easy procedure and reduction of the x-ray exposure. In many cases, CS venography in multiple projections may not be necessary because the single projection separates the CS branches adequately. Therefore it is important to know what CS venography findings in the single projection suggest the necessity of additional CS venography in another projection and how to perform that additional CS venography effectively. This study provided an example, illustrating this fact.

Conflict of Interest

T.Y. is supported by a research grant from Boston Scientific and St. Jude Medical. A.E.E., G.N.K., H.T.M., and V.J.P. have participated in catheter research funded by Biosense-Webster and Irvine Biomedical. G.N.K. has received honoraria from Medtronic, Boston Scientific, and St. Jude Medical. A.E.E. has received honoraria from and served on events committees for Boston Scientific and St. Jude Medical. The electrophysiology fellowship program at the University of Alabama Birmingham receives funding support from Boston Scientific and Medtronic. The other authors report no conflicts.

References

  • 1.

    Jongbloed MR, Lamb HJ, Bax JJ, et al: Noninvasive visualization of the cardiac venous system using multislice computed tomography. J Am Coll Cardiol 45:749–753, 2005.

  • 2.

    Wijetunga M, Cuoco F, Ravi ND, et al: Characterization of the coronary sinus ostium by cardiac magnetic resonance imaging. Am J Cardiol 98:1400–1402, 2006.

  • 3.

    Tada H, Ito S, Naito S, et al: Longitudinally partitioned coronary sinus: an unusual anomaly of the coronary venous system. Pacing Clin Electrophysiol 28:352–353, 2005.

Collaborative development by physicians and industry has resulted in a variety of new tools such as a 9-French (Fr) peel-away sheath, coronary sinus (CS) cannulation assist catheter, vein selectors, and an inner guide capable of delivering up to 7-Fr leads. These advances have reduced implant times by 48% and reduced implant failures from 8% to 2%. The skills needed to use these tools requires the physician to learn and apply interventional principles, including the safe use of contrast, manipulation of open-lumen catheters, effective efficient injection of contrast, and the importance of table position among others. For example, a small catheter with a flexible, tapered tip that telescopes through the delivery guide is used to locate the vein then act as a rail over which to advance the guide is a “vein selector” ( Fig. 30-1 ). Although catheters borrowed from interventional radiology and cardiology can be used as vein selectors, they are the wrong length, the tips are too stiff, and the shapes not ideal. Fortunately, vein selectors are now available in multiple shapes from several different companies ( Figs. 30-2 and 30-3 ).

Figure 30-1, Delivery Guide Advanced Using Vein Selector and Wire as Rail.

Figure 30-2, Variety of shapes used to locate and cannulate target veins over the last decade.

Figure 30-3, Vein Selectors.

The benefits of CRT are dependent on selection of patients who are likely to have improved LV systolic performance, as well as the ability of the operator to deliver that therapy to the optimal region of the left ventricle. Because the anatomy of the coronary venous system is highly variable from one patient to the next, implanting physicians must be capable of adapting their operative approach using the most effective tools and techniques. The transvenous approach most likely to facilitate uncompromising placement of LV leads in the shortest possible time may require the use of tools that are not provided by the manufacturers of pulse generators and leads. The author has developed several tools and techniques that may significantly aid in successful coronary venous lead implantation. This chapter is intended to introduce readers to several specialized tools and procedures that may improve the delivery of coronary venous leads to achieve the optimal benefits of cardiac resynchronization. Although sending patients for surgical epicardial lead implantation or implanting an LV endocardial lead by the transseptal approach are alternatives to coronary venous lead implantation, this chapter will present techniques that can greatly minimize the use of these alternative approaches. Using these newer transvenous approaches may be safer than subjecting the patient to a thoracotomy or the presence of an endocardial lead with its associated risk of thromboembolism. Although recent studies suggest superior hemodynamic performance associated with endocardial compared with epicardial stimulation, this finding may be related to the inability to successfully deliver a pacing lead to an optimal epicardial site.

Although the surgical approach is a convenient option for the implanting physician, maximizing success of the transvenous approaches is stressed because of the limitations of available trans­thor acic, transepicardial, and true epicardial electrodes may be less appreciated, with 15% LV lead failure at 5 years. In addition to lead failure, lead position, morbidity, and mortality must be considered. Utilizing pressure-volume loops Dekker and colleagues found epicardial sites that “did not significantly change LV function and even worsened it in some cases.”

Although data are limited, complications and mortality appear to be much higher with the surgical versus the transvenous approach. In the series presented by Ailawadi and colleagues, surgical lead implantation increases operative mortality and postprocedural complications such as acute renal injury (26.2% vs. 4.9%, P < 0.001) and infection (11.9% vs. 2.4%, P < 0.03) compared with a transvenous approach. Based on analysis of the Replace registry, surgical LV lead mortality may be greater than 8%. In the Replace registry, 48 patients (11% of 434 attempted LV lead placements) had a failed transvenous implantation attempt. There were four deaths in the patients sent for surgical epicardial LV placement.

In addition, surgical LV lead placement is frequently suboptimal for achieving resynchronization with the tendency to be placed along the anterolateral wall of the left ventricle ( Figs. 30-4 and 30-5 ). This fact underscores the importance of ensuring that patients who undergo surgical epicardial lead implantation have a lead placed on the midlateral free wall of the left ventricle.

Figure 30-4, Epicardial Versus Transvenous Lead Placement for Biventricular Pacing.

Figure 30-5, Initial Transvenous Implant (Cardiac Resynchronization Therapy) “Nonresponders.”

Left Ventricular Lead Position and Response

Successful CRT requires more than just pacing the LV; the location of the lead is also important. Since the last edition of this book, multiple publications have examined the possibility of improving the results of CRT by improving the LV lead location at the time of implant. The groups of Khan, Saba, Daya, and others used preimplant echocardiography and Gold and colleagues used LV electrical delay at the time of implant to locate the pacing site for best resynchronization. Sweeney and others retrospectively looked at the reduction of QRS duration as an indicator of good lead position. Many other implanters employ LV electrical delay combined with reduction in QRS duration at the time of implant to confirm the optimal site for lead placement. However, the rate-limiting step for targeted LV lead placement is always the ability to get the LV lead to the desired location. Using standard tools, this ability to deliver the lead to the optimal site may be as low as 30% as demonstrated in the STARTER Trial.

Although not true for every patient, the midlateral wall of the LV seems to be the best location for LV resynchronization ( ). When considering a patient who is not responding to CRT, the lead position is often the problem. The left anterior oblique (LAO) view on fluoroscopy at the time of implantation should define the LV lead position ( ). However, if the fluoroscopy is not performed in a standard fashion, it can be deceptive. Kistler and associates describe a case in which it became apparent, from analysis of the electrocardiogram (ECG) that a lead that was fluoroscopically thought to be in the LV at the time of implantation was actually in the right ventricle (RV). Another example of fluoroscopic error is shown in Figures 30-6 and 30-7 . The LAO fluoroscopic image in Figure 30-6A appeared to document a lateral position. However, the lateral chest radiograph (see Fig. 30-6B ) demonstrated the anterior location. In Figure 30-7A , the steeper LAO projection reveals the anterior nature of the first (“nonresponder”) LV lead position. It is important for the implanting physician to take personal responsibility for reviewing the final location of the LV lead, to ensure that the patient has received the best possible lead position. In follow-up of patients after implantation, we demonstrated that the LV-RV lead separation on the lateral chest radiograph is essential in evaluating “nonresponders” in whom LV lead placement has been “successful.” Heist and colleagues demonstrated that the acute hemodynamic effect of CRT is predicted by the distance between the LV and RV leads as measured on the lateral chest radiograph taken after the procedure. The importance of the chest x-ray was reinforced by Singh et al.

Figure 30-6, Fluoroscopy and Chest Radiography at Initial Implantation of Left Ventricular (LV) Lead.

Figure 30-7, Fluoroscopy and Chest Radiography at Second Implantation.

Placement of the LV lead on the anterior wall of the LV is suboptimal (at best) and has been demonstrated to deteriorate LV function in some patients regardless of the method of implantation. When the LV lead is on the midlateral wall, its position on a lateral chest radiograph is directly posterior. Figure 30-8 shows the typical postimplantation chest radiographs of a “responder” in whom the LV lead is located on the midlateral wall of the LV. Note that the LV and RV leads are maximally separated on the lateral chest radiograph.

Figure 30-8, Chest Radiographs of Patient Showing Response to Cardiac Resynchronization Therapy (CRT).

Figure 30-9 includes the lateral chest radiographs of two patients who did not show response to CRT with their original lead position but did respond when a lead was positioned on the midlateral free wall. Figure 30-9A is the lateral chest radiograph of a “nonresponder” in whom the lead was placed in the anterior interventricular vein; patients with a lead in this location are not expected to show response. Figure 30-9C , however, is the lateral chest radiograph of a patient who showed no response even though the LV lead had been placed in the vein to the midlateral free wall. What happened? The LV lead is advanced distally in the midlateral vein, which wraps around anteriorly toward the septum. Although the lead was started in the vein to the midlateral free wall, it ended up close to the septum in proximity to the RV lead. Note that in Figures 30-9A and C , the tip of the LV pacing lead is closer to the RV pacing lead than the ideal position seen in Figure 30-8B . When a second LV lead was placed this time on the lateral wall (see Fig. 30-9B and D ), the patients improved clinically and were regarded as responders.

Figure 30-9, Chest Radiographs of Cardiac Resynchronization Therapy (CRT) Nonresponders Versus Responders.

The clinical question raised in Figure 30-9C is whether repositioning the LV lead to a more proximal position in the same vein, thus increasing the RV-LV separation, would change a “nonresponder” to a “responder.” Figure 30-10 illustrates the original and a new, more proximal position in the same vein of a patient in whom such repositioning was performed. The RV-LV lead separation was increased, and the patient demonstrated a marked symptomatic improvement with reduction in both serum creatinine and diuretic requirement.

Figure 30-10, Lateral Chest Radiographs Before and After Repositioning.

Figure 30-11A is the lateral chest radiograph of a patient in whom coronary vein venoplasty was ultimately required for LV lead placement. The vein draining the midlateral wall was distal to a stenosis in the main body of the CS. Although the original implantation was regarded as “successful,” the pacing lead was not placed on the midlateral wall of the LV. The patient did not improve after the procedure and was regarded as a CRT “nonresponder.” At a repeat procedure, where venoplasty of the main body of the CS was performed, the lead was placed on the lateral wall of the LV (see Fig. 30-11B ); dramatic resolution of symptoms eliminated the need for a heart transplant. Both the acute hemodynamic effect and the subsequent clinical response to CRT are predicted by the RV-LV lead separation on the lateral chest radiograph. On the basis of the work of Heist and colleagues, the RV-LV separation in the horizontal plane is more important than the total RV-LV separation, and the RV-LV separation in the vertical plane was not predictive.

Figure 30-11, Chest Radiographs of Nonresponder Before and After Coronary Sinus (CS) Venoplasty and Lead Repositioning.

Newer Tools for Delivery of Coronary Venous Leads

Since 1997, LV pacing leads have evolved from unipolar 6-Fr stylet-driven to 4-Fr, quadripolar, over-the-wire (OTW) designs. Although there have been significant improvements in the design of LV pacing leads, their placement continues to be limited by the coronary venous anatomy of each patient. Frequently, guide support is required because a wire designed for angioplasty does not provide adequate support to advance the LV lead into the desired location within a coronary vein ( Fig. 30-12 ). Adequate guide support is present when the tip of the guide wire rests securely within the target vein and the back of the guiding sheath is supported by the CS such as occurs with a catheter where the tip is preshaped specifically to cannulate the target vein and not the CS. The magnitude of support provided by the inner guide depends on its shape, as shown in Figure 30-13 . The compound shape (Panel B) offers greater support than the single curve (Panel A) because the secondary curve is supported by the back wall of the CS. For the purposes of this chapter, an “inner guide” is defined as a braided slittable catheter preshaped for LV lead delivery (not for CS access) that is inserted through a separate catheter in the CS. Similarly, a CS access catheter is defined as a removable catheter designed specifically for CS cannulation, which provides a platform for LV lead delivery. CS access catheter can, on occasion, provide guide support when it inadvertently cannulates the target vein or is forced into the vein. Forcing a straight tip catheter requires an angle of less than 30 degrees, a situation where guide support is usually not required. Furthermore, there is the potential for dissection of the coronary vein as the straight tip is forced around the curve ( Fig. 30-14 ).

Figure 30-12, Despite Wire Placement, Pacing Lead Does Not Track Into Target Vein.

Figure 30-13, Shape of Delivery Guide Determines Magnitude of Support.

Figure 30-14, Perforation of Vein by Coronary Sinus (CS) Access Catheter.

An inner guide is the most reliable way to deliver a lead to the target vein particularly when the anatomy is difficult ( Fig. 30-15 ). However, an inner guide may be required even when the anatomy seems favorable ( Fig. 30-16 ). In addition, the inner guide catheter makes it easier to deal effectively with lead instability, high thresholds, phrenic pacing, or to inject contrast to identify branches. The inner guide catheter also provides support to reposition the lead, change to a lead with a different size shape, and/or method of fixation. Finally, because the inner guide allows the stylet to be safely advanced to the lead tip ( Fig. 30-17 ), the final step of removing larger guiding catheters from the CS is less likely to displace the lead. Accordingly, the approach to LV lead implantation described in this chapter is based on using a guide-support based delivery system.

Figure 30-15, Use of Delivery Guide.

Figure 30-16, Delivery Guide Required for Lead Placement.

Figure 30-17, Reducing Risk of Lead Dislodgment as Catheters Are Removed.

The collaboratively developed delivery system mentioned above is composed of three separate components: (1) A 9-Fr internal diameter (ID) peel-away CS access catheter with braided CS cannulation assist catheter (braided core); (2) a 5-Fr vein selector (one of three shapes); and (3), an inner guide. Dividing the delivery system into three parts allows the design of each component to be optimized for its particular function. Although an LV lead can be delivered with a single or two-component system, having all three components provides the best opportunity for success in the least amount of time and with the shortest learning curve.

Coronary Sinus Access Catheter

The role of the CS access catheter is to provide rapid reliable CS cannulation, provide a stable platform of adequate diameter with options for difficult LV lead placement, and be removable without lead displacement (peel-away being less likely to displace than slicing). The “Worley” implant system requires only one shape (two sizes) for successful CS cannulation whereas the device manufacturers provide multiple shapes that are chosen based on CS anatomy. Further details are provided in the CS cannulation section.

Telescoping Assist Catheter

This is a catheter to assist insertion of catheter and/or cannulate the CS ( Fig. 30-18 ). Further details are provided in the CS cannulation section.

Figure 30-18, Telescoping Cannulation Assist for Coronary Sinus (CS) Access Catheters.

Vein Selector

This is a braided catheter with a soft tapered tip designed to (1) locate the target vein with contrast injection; (2) deliver a guidewire(s) into the vein; and (3) serve as a rail (with the wires) over which to advance the delivery guide into the target vein. Over the last 10 years we have used a variety of shapes to locate and cannulate target veins (see Fig. 30-2 ). Through the process of elimination we have arrived at the three shapes shown in Figure 30-3 . These vein selectors can also be used with the delivery guides of other manufacturers. The “standard” is included with Merit Medical (San Pedro, CA) and Pressure Products (San Pedro, CA) delivery guides.

Inner Guide

This is a braided catheter designed to provide support for inserting the LV lead directly into the target vein (not for CS access). Boston Scientific (Marlborough, MA), Medtronic (Minneapolis, MN), St. Jude Medical (St. Paul, MN) and Biotronik (Berlin, Germany) now offer sliceable delivery guides for 5-Fr and smaller leads. In addition, the hemostatic hubs are integrated into the catheter. Pressure Products and Merit Medical offer two size sliceable delivery guides, a 9-Fr outer diameter (OD) for 7-Fr and smaller leads and a 7-Fr OD for leads 5 Fr and smaller. (See the section on commercially available delivery systems.)

Previous Approach to the Shape and Use of Inner Guides

The third edition emphasized matching delivery guide shape to the target vein anatomy for several reasons. First, at that time we used either interventional guides from radiology or the first generation Pressure Products delivery guide ( Fig. 30-19A ), both with very firm tip sections. The firm tip sections could not be advanced into the target vein or did not remain stable once advanced ( Fig. 30-20 ). However, with the new soft tip design (see Fig. 30-19B ), the Merit Medical/Pressure Products delivery guide can be advanced deep into the target vein and remains stable. Second, it initially appeared that the delivery guide could be used to reliably locate the vein, advance a guide wire into the vein, and then advance the lead over the wire into the vein. Although effective in some cases, we found that the delivery guides were not optimal for small or off-axis target veins (see Fig. 30-1A ), necessitating the addition of a small diagnostic catheter telescoped through the delivery guide (see Fig. 30-1B ). Thus it became clear that a small diagnostic catheter (vein selector) was an essential component of a guide-support based delivery system and needed to be included with the delivery guide (see Fig. 30-3 ).

Figure 30-19, Comparison of Tip Section of Original and Current Delivery Guides.

Figure 30-20, Stiff Tip Prevents Secure Advancement of Interventional and Delivery Guides Into Target Vein.

New Approach to the Shape and Use of Delivery Guides

Recognizing that a vein selector will be needed to locate and cannulate the target vein in at least some cases and that the soft tip of the new Merit Medical/Pressure Products delivery guides can be advanced to a stable position deep in the vein if needed, we now rely on the shape of the vein selector for off-axis and difficult veins and use a single shape delivery guide. Using the included vein selector and wire(s) as a rail, the “Renal” delivery guides ( Fig. 30-21 ) can be inserted into the vast majority of target veins regardless of takeoff. Now that we have the vein selectors, rarely is one of the other shape delivery guides required (Hook, Hockey Stick, or Multipurpose).

Figure 30-21, Renal-Shaped Delivery Guides With Vein Selector.

Left Ventricular Lead Implantation Using the Author-Designed Delivery System

Step-by-Step Summary

Start a free flowing IV in a proximal vein on the side of the implant or both sides if there is a previously implanted system.

Prepare the patient for contrast. Start normal saline 3 mL/kg/hr for 1 hour starting 1 hour before the procedure then 1 mL/kg/hr during and continuing for 6 hours following the procedure.

Prepare the room. In addition to the guides and sheaths that will be used for every case, the following must be readily available in the room: (1) Hydrophilic wires 0.035 in and 0.018 in angled tip wires; (2) Torque devices for 0.014-0.025 in wires and 0.025-0.038 in wires; (3) Extra stiff 035 in extra-support guide wire; (4) Vert, that is, a 5-Fr hydrophilic left vertebral-shaped angiographic catheter; (5) Subclavian venoplasty balloon 6 mm × 4 cm 30-60 cm; (6) Vein selectors (three shapes Merit Medical); (7) Coronary Balloon rapid exchange 2.5 mm × 14-16 mm and a 3.0 mm × 14-16 mm; (8) Balloon inflation device.

  • A.

    Prepare the implant table. In addition to the usual implant equipment

    • 1.

      Assembled contrast injection system

    • 2.

      50 mL of undiluted contrast

  • B.

    Elevate the legs to increase central pressure

  • C.

    Get venous access using contrast

    • 1.

      Position the implanting physician, scrubbed and ready to stick.

    • 2.

      Inject 10-30 mL of contrast and flush with 30 to 50 mL of saline

    • 3.

      Stick the vein with the contrast flowing

  • D.

    Get three separate axillary vein access

    • 1.

      Two short wires

    • 2.

      One long wire

    • 3.

      Coil the long wire and clip it to the drapes

  • E.

    Insert the RV and right atrium (RA) leads

  • F.

    Turn the implant table perpendicular to patient

  • G.

    Position fluoroscopy in a close and comfortable position

  • H.

    Unclip the long wire and insert the long peel-away sheath

  • I.

    Attach the braided core to the injection system and insert into the sheath

  • J.

    Torque the catheter with BOTH hands and have the assistant inject

  • K.

    Locate the CS and cannulate the CS with the braided core and sheath

  • L.

    Perform an occlusive CS venogram

  • M.

    Select the vein and decide on lead shape and size

  • N.

    Choose the appropriate SHAPE vein selector (three choices)

  • O.

    Choose the appropriate SIZE “Renal” shape lateral vein introducer (LVI) delivery guide

    • 1.

      7-Fr ID for leads ≤5 Fr

    • 2.

      9-Fr ID for leads ≤7 Fr

  • P.

    Load the vein selector into the delivery guide

  • Q.

    Attach the injection system to the vein selector

  • R.

    Insert the guide/vein selector into the CS access catheter (Worley-STD)

  • S.

    Advance until the delivery guide reaches the tip of the Worley-STD

  • T.

    Advance the vein selector out of the delivery guide into the CS

  • U.

    Put BOTH HANDS on the vein selector

  • V.

    Rotate the vein selector laterally just above the target (based on CS venogram)

  • W.

    Slide the vein selector up and down the lateral wall of the CS

  • X.

    Have an assistant inject contrast when either of the events below occur

    • 1.

      The tip drops outside the curve of the CS; or

    • 2.

      The tip stops moving freely

  • Y.

    Insert a floppy 0.014-inch hydrophilic angioplasty wire into the vein

  • Z.

    Advance the vein selector slightly into the vein

  • AA.

    Insert an extra-support 0.014-inch hydrophilic angioplasty wire into the vein

  • AB.

    Advance the vein selector further over the two wires to a stable position in the vein

  • AC.

    Hold the wires and vein selector stable and advance the delivery guide

  • AD.

    Rotate the vein selector gently as it approaches the ostium of the vein

  • AE.

    With the delivery guide at the ostium advance/withdraw the vein selector as needed

  • AF.

    Make certain the equipment table is perpendicular to the patient (T-bone)

  • AG.

    Remove the vein selector retaining the wires

  • AH.

    Advance the lead into the vein, remove the wires and test

  • AI.

    Advance a soft curved stylet to the tip of the lead

  • AJ.

    Position the tip of the access catheter in the proximal CS

  • AK.

    Position the patient under anterior-posterior (AP) fluoroscopy, such that

    • 1.

      The tip of the lead is at the right edge of the screen (not in the middle)

    • 2.

      Or the CS ostium is in the middle of the screen

  • AL.

    Slice the delivery guide

  • AM.

    Remove the peel-away CS access catheter from the CS, without displacing the lead

    • 1.

      DO NOT crack the hub

    • 2.

      While watching the lead tip under fluoroscopy, withdraw the sheath

    • 3.

      Add slack to the lead as needed

  • AN.

    When the hemostatic hub of the sheath reaches the IS-1 connector

    • 1.

      Have the assistant compress the walls of the sheath against the lead

    • 2.

      And crack the hub and peel down to the assistant's fingers

  • AO.

    Slide the remaining sheath back until it clears the lead

    • 1.

      Have the assistant secure the lead

    • 2.

      Finish peeling the sheath

  • AP.

    Adjust lead slack in the LAO projection

  • AQ.

    Remove the stylet quickly

  • AR.

    Secure the lead

Left Ventricular Lead Implantation with the Worley Delivery System and Interventional Techniques

Details and Rationale

This section describes the recommended tools and techniques for implanting LV leads and the rationale for this process.

When a CRT implantation is begun, there is no way to predict what lies ahead. For example, it may be difficult to find the vein, the subclavian vein may be stenotic or occluded, the CS ostium may be difficult to locate, and the main CS may be tortuous. The CS venogram may reveal a range of target veins from very easy to extremely difficult to cannulate. Once the lead is in the target vein, the implanter must be prepared to deal with phrenic nerve pacing or high pacing thresholds. Once the lead is in a satisfactory location, the implanter must anticipate and prevent the lead from being displaced either spontaneously or as the final catheter or stylet is removed. A CRT implantation ultimately fails as a result of patient anatomy for which the implanter is not prepared. To succeed, the implanter must be prepared to deal with whatever anatomy is encountered, starting with venous access and ending with the final removal of the stylet.

Prepare the Patient for the Use of Iodinated Contrast Material

The safe use of contrast improves safety, reduces implant time, and is essential to efficient effective LV lead delivery ( Fig. 30-22 ). Rather than just trying to limit contrast, it is better to take steps to prevent nephropathy. Use of contrast can then be individualized; many will be at relatively low risk, whereas others (diabetics with increased creatinine) remain at high risk. Because the serum creatinine can vary substantially in CRT patients depending on volume status, we recommend hydration for all patients. Hydration: Normal saline or sodium bicarbonate 3 mL/kg/hr starting 1 hour before the procedure continued during the procedures and continuing 6 hours after the procedure. This hydration protocol is as effective as giving 1 mL/kg/hr of normal saline 12 hours before, during the procedure, and for 12 hours after the procedure, and the patient receives less volume. Although volume overload is possible, it is rare and offset by the advantage of preventing nephropathy. Caution: hydration should not be started until the patient is on the way to the room. Ideally the 3 mL/kg normal saline loading bolus is completed just as the procedure starts. If hydration is started in anticipation and the procedure must be delayed for several hours, the patient will not benefit from the bolus and will receive excess saline increasing the risk of CHF.

Figure 30-22, Simplified System to Allow Assistant to Inject Contrast While Operator Manipulates Catheter With Both Hands.

Equipping and Setting up the Room

Four of the most important and most easily overlooked parts of LV lead implantation are mechanical issues that can be easily resolved before the procedure starts. Careful attention to these issues can make the difference between an agonizing unsuccessful attempt and a 15-minute LV lead placement. Actions to avoid these issues are discussed here.

Collect Available Left Ventricular Lead Implantation Equipment and Review Its Use

Possibly the worst mistake that can be made is to assume that the equipment required for a successful efficient LV lead implantation either is in the room or has been provided by the manufacturer. Some of the equipment is readily available in the hospital but is not part of the usual repertoire of many implanting physicians. Knowledge of the equipment used in interventional radiology and interventional cardiology can be extremely useful during an LV lead implantation (see Interventional Implant Equipment List). The technical staff and physicians from interventional cardiology and radiology commonly have helpful ideas for solving the mechanical problems posed by an LV lead implantation, and equipment specifically tailored to LV lead placement is slowly making its way into the world of electrophysiology. Access to these new tools can make the difference between an easy success and a painful, demoralizing failure with a bad outcome for the patient.

Organize the Equipment to Be Readily Available in the Room

It is important to remember that the equipment one needs is not commonly available in a room that is used for either pacemaker implantation or an electrophysiology study. To avoid spending more time looking around in the interventional cardiology and radiology laboratories than actually working on the patient, one should make certain of having the most basic equipment in the room. These tools are additional to the device manufacturer's equipment and sheaths used for pacemaker implantation. To be certain, the proper tools, regardless of the room, are included in our “BiV Cart.” This cart also contains equipment for performing subclavian and coronary vein venoplasty ( Fig. 30-23A and B ).

Figure 30-23, Biventricular (BiV) Cart.

Assemble the “Always Used” Equipment on the Table before Starting

Having a routine and setting the table with the equipment needed for the procedure gives the operator the freedom to concentrate on the procedure and help avoid “rethinking” the tools for each implantation ( Fig. 30-24 ).

Figure 30-24, Instrument Table Position During Left Ventricular Lead Implantation.

Pay Careful Attention to the Orientation of the Instrument Table during Various Stages of the Procedure

It is truly remarkable how important the position of the instrument table can be to a successful implantation. Figure 30-24A demonstrates the usual “backfield” position of the instrument table. The table in this position until CS access is achieved, at which point the table is turned perpendicular to the patient (see Fig. 30-24B ). Once the LV lead is in place and it is time to start removing the guide and/or sheath, the table is returned to the “backfield” position so the assistant can support the sheath and lead during sheath and guide removal. Despite the logic of having the implant table on the same side as the implanting physician, centers can be resistant or even hostile when advised to move the table to the other side. The hostile reaction may be more likely when the operating room sends a scrub team to the electrophysiology (EP) laboratory to assist. It is important that the team who assists the implanting physician is dedicated to patient outcome, the EP lab, and CRT implantation.

The perpendicular position of the table from the start of CS cannulation until removal of the guide and or sheath can be cumbersome with standard tables, for the following reasons:

  • The legs of the table closer to the patient interfere with the position of the operator's feet and the fluoroscopy pedals.

  • The legs of the table interfere with rotation of the fluoroscopy unit, particularly in the right anterior oblique (RAO) position.

  • The height of the standard instrument table is lower than the height of the patient, as shown in Figure 30-24B . As a result, wires and catheters do not make a smooth transition from the patient to the table.

The custom-built table shown in Figure 30-25A and B addresses all three issues. The legs are recessed to provide room for the fluoroscopy unit, the operator's feet, and fluoroscopy pedals. The height is adjustable so that the top of the table can be raised to reduce the vertical step off between the patient and the table. Interventional principles teach that when working with catheter, it is important that the implant table is turned perpendicular to the patient table (T-bone position) so the wires and catheters exit the body falling naturally onto the table (see Fig. 30-24B ). Further, the assistant is in the optimal position to assist with the catheter manipulation, contrast injection, and wire exchanges required for LV lead implantation and the use of balloons. Application of torque to the catheters is not lost in a right angle and the open-lumen catheters are not prone to kink. Testing the LV and RV simultaneously for pacing thresholds can be very difficult with standard testing cables. Simply attaching an additional alligator clip eliminates this problem ( Fig. 30-26 ).

Figure 30-25, Custom-Made Table to Facilitate Left Ventricular Lead Implantation.

Figure 30-26, Biventricular Pacing Cables.

Approach to Contrast

An important point that is frequently overlooked is the approach to contrast injection. EP physicians accustomed to working alone with solid catheters naturally try to inject contrast and control the catheter. However, it is clear from interventional principles that catheter control is degraded when one hand is removed from the catheter and attention is turned to contrast injection. Suboptimal catheter control will result in increased use of contrast and a greater chance of misadventure. For optimal catheter control the operator keeps both hands on the catheter and attention focused on tip position ( Fig. 30-27 ).

Figure 30-27, Contrast Injection by Operator and Assistant.

Venous Access for Left Ventricular Lead Implantation

At first, venous access may seem like a minor issue, but keep in mind the cascade of events that follows a difficult venous access. If compression between the clavicle and first rib, friction between the leads, or subclavian stenosis restricts manipulation of the leads or sheath, the operator is handicapped for every subsequent step. The operator is not prepared for difficult anatomy in subsequent steps if the result of the first step is limiting. A poorly considered initial venous access will be problematic throughout the procedure.

Preventing Restricted Catheter/Lead Movement

Separate Access for Each Lead

It is valuable to have separate access sites for each lead to reduce the interaction among the three leads. If it is possible to obtain only two access sites, the RV and RA leads should be placed through the same access site to minimize the potential for movement of either lead to displace the LV lead. When leads share the same access, friction between the two may result in the stable lead being inadvertently withdrawn by manipulation of the other lead. To help prevent the lead from being withdrawn, one should keep the stylet of the stable lead at the junction between the RA and superior vena cava (SVC) until manipulation of both leads is complete, even after the stable lead is tied down. Without a stylet, the stable lead can withdraw, even when tied to the muscle, by forming an “S” configuration within the subclavian distal to the tie-down, as shown in Figure 30-28 .

Figure 30-28, Friction Between Lead and Guide Pulls Back Lead, Even Though Sewn Down.

Axillary versus Subclavian Venous Access

With subclavian vein access, compression between the first rib and clavicle can restrict lead manipulation. In a nonbiventricular (BiV) or an easy BiV implantation, restricted manipulation of the leads may be only a mild annoyance. However, precise manipulation is required, and the friction may make it impossible to place the LV lead. Axillary vein access ensures that lead manipulation will be unrestricted by compression between the clavicle and first rib. Standard axillary vein access (entry into the axillary vein at or central to the cephalic vein) also minimizes the risk of lead fractures and/or pneumothorax ( Fig. 30-29 ). In some centers the “extra thoracic” axillary vein access (lateral to the cephalic vein) is employed, which may reduce the risk of pneumothorax but creates an acute angle at the entry site making catheter manipulation difficult and probably increases the risk of lead fracture.

Figure 30-29, Axillary Vein Venogram Before and After Insertion of Retention Wire.

Response to Subclavian Obstruction in Patient with Preexisting Leads

Approximately 20% to 30% of patients with previously implanted leads will have one or more stenotic areas between the site of venous insertion and the RA ( Figs. 30-29 to 30-32 ). Before the advent of LV lead placement, the response of the implanting physician to a subclavian stenosis was to either go to the other side or advance progressively larger dilators until the sheath could be advanced. Dilator opening of a stenotic area, if possible, is always incomplete. The stenotic area continues to restrict manipulation of both wires and catheters making LV lead placement far more difficult if not impossible. Furthermore, distal stenotic areas cannot be addressed by the use of dilators. Venoplasty safely creates a far less restricted access than progressively larger dilators and can also address more central stenoses (see Figs. 30-31 and 30-32 ). A recent survey of 30 implanting physicians using this approach revealed that none have had a complication related to performing subclavian venoplasty for access in the setting of chronic leads.

Figure 30-30, Contrast Injection Demonstrates Typical High Grade Stenosis.

Figure 30-31, Dilation of Peripheral Subclavian Vein Occlusion.

Figure 30-32, Dilation of Proximal and Distal Subtotal Venous Occlusions in Same Patient.

The Platform for Left Ventricular Lead Placement

The lumen size, catheter shape, and method of removal (cutting vs. peeling) influence the suitability of a CS access catheter as a platform for LV lead placement.

Lumen Size

The platform available for LV lead placements starts with the choice of venous access for the LV lead. Many physicians have used a short peel-away sheath to access the venous circulation for insertion of leads in the RA and RV ( Fig. 30-33A ). When using a catheter supplied by device manufacturers for CS access, one typically starts with a short 9-Fr sheath for venous access. The internal diameter of the CS access catheter is thus only 6 to 7 Fr. The small-caliber CS access sheath limits the implanting physician in several ways. For example, a small-caliber CS access sheath allows for an inner guide that only can deliver 5 Fr or smaller leads without a buddy wire. By comparison, when the sheath shown in Figure 30-33B is used for venous access, it also serves as the CS access catheter such that a 9-Fr internal diameter lumen is available in the CS. The larger-caliber CS access sheath alloys the use of a larger inner guide that can deliver up to 7-Fr lead with a buddy wire, as well as the single catheter snare technique and support wires. Long peel-away sheaths used for both venous and CS access are shown in Figures 30-33B and 30-34 .

Figure 30-33, Venous Access Sheaths for Left Ventricular Lead Placement.

Figure 30-34, Properly Curved Coronary Sinus Sheath.

Catheter Shape

Catheter shape influences ease of CS access, reduces the propensity for kinking, improves stability during the procedure, and reduces the propensity to displace the lead when the sheath is removed. A catheter that is curved to fit the anatomy of the coronary venous system is optimal. There are several considerations when selecting a CS access catheter. First, the shape of the CS access catheter determines how easy it is to cannulate the CS. An anatomically optimized CS access catheter is easier to place in the CS than other shapes (see below). Second, the shape of the CS access catheter determines whether it is prone to kinking. Catheters tend to kink when bent. Thus, if the manufactured shape of the catheter matches the anatomy, it is less likely to bend and kink.

Third, the shape and size of the CS access sheath determines the amount of support that it provides. If the CS access catheter is not anatomically shaped it must be deformed from its original shapes to fit the cardiac anatomy. The deformed catheter is under tension and prone to dislodge from the CS. An anatomically curved catheter is not only stable in the CS but provides support during LV lead placement as it contacts the lateral wall and floor of the RA and the eustachian ridge as illustrated in Figure 30-34 . Finally, the shape of the CS access catheter determines whether it is likely to displace the lead when it is removed from the CS. A deformed CS access catheter that is under tension in the CS loses its support as it is withdrawn and suddenly resumes the original shape, thereby directing its tip to the floor of the RA. This sudden movement may pull the lead out of the target vein ( Fig. 30-35 ). By comparison, an anatomically shaped catheter is not under tension as it rests in the CS. When removed, the tip of such a guide rises above the CS as illustrated in Figure 30-36 .

Figure 30-35, Removal of Nonanatomic Catheter.

Figure 30-36, Removal of Anatomically Shaped Catheter.

Cutting versus Peeling to Remove the Coronary Sinus Access Sheath

There are two major ways that the CS access sheaths are designed to be removed: by a peel-away design or by being cut (slit) with a sharp tool. Peeling is a familiar, easy procedure that can be performed in a stable, controlled manner. When both venous and CS access are the same peel-away sheath, the last step of lead placement is to peel the sheath away once the lead is positioned. If the CS access catheter is braided and placed through a short sheath, the last step of lead placement is to slice the steel mesh in the wall of the guide. Many implanting physicians find it clumsy and difficult to cut the sheath in this manner, and many leads have been displaced while cutting. This unfortunate outcome requires that the coronary venous lead implant procedure be restarted from the beginning. In contrast, if one starts with a long peel-away sheath for both venous and CS access, the risk of lead displacement at the end is decreased. This issue is covered in detail in the section on removing the guide sheath.

When CRT implantation first began, the device manufacturers initially offered long peel-away sheaths but quickly switched to braided, sliceable catheters for several reasons. First, the initial generation of peel-away sheaths did not have the torque control required for reliable CS cannulation. And second, the shape of the initial peel-away sheaths as shown in Figure 30-37 were not anatomically shaped and thus had to be bent to reach the CS. This resulted in kinks with collapse of the lumen as illustrated in Figure 30-38 . To maintain the advantages of peel-away CS access catheters, several improvements were made. First, torque control was provided through the use of a temporary metal braid inside a long peel-away sheath (the braided core). The braided core also functions as a telescoping catheter to assist in cannulation of the CS. Once the sheath is in the CS, the braided catheter (core) is removed, leaving the peel-away sheath in place. Second, kinking was greatly reduced by manufacturing the sheath to an anatomic shape that better fits the anatomy of the CS.

Figure 30-37, Original Long, Peel-Away Sheath Designed for Both Venous Access and Coronary Sinus Cannulation/Access.

Figure 30-38, Peel-Away Sheaths Kink at Sharp Bends Unless Curved at Manufacture.

Coronary Sinus Access for Left Ventricular Lead Implantation

The first step in placing a coronary venous lead is to create a stable platform in the CS with the access catheter ( and ). Al-Khadra has pointed out that failure to cannulate the CS continues to contribute significantly to failure of LV lead implantation. Factors that influence the success of CS cannulation, in addition to experience and patient anatomy, include (1) positioning the table perpendicular to the patient; (2) using a contrast injection system with a Y-adapter and rotating hemostatic valve; (3) using both hands for catheter manipulation; (4) use of full-strength contrast; (5) catheter shape; and (6) a telescoping CS cannulation assist catheter.

Contrast or Not for Coronary Sinus Cannulation?

Several observations and recommendations can be made regarding the use of contrast to cannulate the CS.

Limitations of the Noncontrast Method

Using an EP catheter or probing with a wire are two noncontrast approaches to CS cannulation. When EP catheter CS cannulation is difficult or fails, many times the actual problem is not finding the CS ostium but advancing the catheter into the CS. Without contrast, the operator cannot determine whether the tip of the wire or catheter are in the ostium of the CS until the wire/catheter actually advances into the CS ( Fig. 30-39 ). In addition, noncontrast CS cannulation requires working with the fluoroscopy in the uncomfortable LAO projection, which increases radiation exposure. Although the CS can be cannulated by probing with a wire or EP catheter and then advancing once the wire or catheter enters the CS, this approach often takes more time than is necessary. More importantly, the operator does not develop the catheter manipulation skills required for successful cannulation of a more challenging CS.

Figure 30-39, Difficulty Advancing Guide Beyond Coronary Sinus (CS) Ostium, Sigmoid CS, and Large Proximal Vein.

Limitation of the Contrast Method

Transient renal insufficiency may result from administration of contrast agents, though this risk can be minimized by identifying patients who are at risk for contrast-induced nephropathy and by using intravenous saline or sodium bicarbonate as discussed above.

Turning Failure Into Success With the Use of Contrast

Figure 30-39 demonstrates two cases where CS cannulation failed without the use of contrast because the operator did not recognize that the tip of the catheter was in the ostium. With contrast it was easy to find the ostium but difficult to advance the catheter beyond this point. CS cannulation with contrast allows for a two-step process: (1) locating the CS ostium and (2) advancing the sheath or guide into the CS. The combination of contrast, an injection system, an appropriately shaped catheter, table position, and proper catheter manipulation may greatly improve the success of CS access.

Catheter Shape for Coronary Sinus Cannulation

As mentioned above, the shape of the CS access catheter has an important impact on the ease of CS access. How catheter shape influences cannulation success is described in detail below.

Catheter Shape and the Anatomy Surrounding the Coronary Sinus Ostium ( Case Study 30-1 )

Successful location of the CS ostium is facilitated by a complete understanding of the anatomy. Figure 30-40 illustrates the structures that affect locating the ostium. In Figure 30-41A , it is clear that a catheter approaching the CS ostium along the posterior wall of the RA will be deflected away from the ostium by the eustachian ridge. When one approaches the CS from below (see Fig. 30-41B ), catheter entrance is blocked by the thebesian valve. The key to easy and rapid location of the CS ostium is for the catheter tip to approach this opening from the posterior-superior tricuspid annulus ( Fig. 30-42B ), using the eustachian ridge and thebesian valve to direct the catheter toward (not away from) the ostium as seen with the femoral approach where the catheter reaches over the eustachian ridge, approaching the ostium from above as illustrated in Figure 30-42A . With the table perpendicular to the patient, a contrast injection system, and the application of counterclockwise torque on the catheter with both hands, a properly shaped catheter can be directed toward the CS ostium from the posterior-superior tricuspid annulus. This technique uses the eustachian ridge and thebesian valve to guide the tip of the catheter toward the ostium. Figure 30-43 demonstrates the effect of counterclockwise torque. Initially, the tip is directed posteriorly where it contacts the heart. With additional torque the tip moves inferiorly and toward the RA. To approach the CS from above, the catheter tip must start superior and on the RV side of the ostium. If the guide starts at or below the CS ostium, counterclockwise torque directs the tip posteriorly and inferiorly away from the ostium into the RA ( Fig. 30-44 ).

Figure 30-40, Anatomic Structures Surrounding Coronary Sinus Ostium.

Figure 30-41, Eustachian Ridge and Thebesian Valve Inhibit Coronary Sinus Cannulation.

Figure 30-42, Thebesian Valve and Eustachian Ridge Assist Coronary Sinus Cannulation.

Figure 30-43, Effect of Counterclockwise Torque When Catheter Tip Starts Above Coronary Sinus.

Figure 30-44, Effect of Counterclockwise Torque When Catheter Tip Starts Below Coronary Sinus.

Changing the shape of a traditional catheter by adding a “proximal curve” ( Fig. 30-45 ) places the tip above the CS on the tricuspid annulus or in the RV so that torque will direct the tip into the CS. Currently, all the device manufacturers provide a braided catheter with an anatomic-shaped proximal curve ( Fig. 30-46 ). To provide the torque control required for CS cannulation and still retain a peel-away sheath, the “Worley Sheath” uses a temporary metal braided core ( Fig. 30-47A -C). The extra length of the braided core also serves as a telescoping cannulation assist catheter ( Fig. 30-48 ). By extending the braided core, the implanter can change the trajectory and shape of the CS access catheter (see Figs. 30-47B and C, and 30-48B ). St. Jude Medical offers cannulation assist catheters (see Fig. 30-18 ) as additional tools with their new delivery system (CPS AIM SL CSL and CPS AIM SL AL2).

Figure 30-45, Starting Position of Catheter With “Proximal Curve.”

Figure 30-46, Three Coronary Sinus Access Catheters.

Figure 30-47, Braided Guide for Torque Control and Shape Modification.

Figure 30-48, Demonstration of Torque Control and Change in Shape and Trajectory.

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