Invasive Hemodynamic Diagnosis of Cardiac Disease

Percutaneous Radial Artery Technique

Radial artery access has become the default approach for many labs ( Fig. 22.1 ). Compared with femoral artery access, transradial procedures have a lower risk of bleeding and vascular complications, superior patient comfort, and improved efficiency in postprocedural care. Documentation of adequate dual blood supply to the hand by either the Allen or the Barbeau test is no longer required in most patients.

In preparation for radial access, the arm should be placed on an appropriate board, abducted at a 30- to 45-degree angle, and the wrist should be hyperextended over a gauze roll. Unless prompted by anatomy or demand (e.g., left internal mammary artery injection), the right radial artery is used. Its distal course can be mapped by palpation or ultrasound; the latter reduces the difficulty of access and can be used to screen for small radial arteries or anatomical challenges before radial sheath insertion. Only a small amount of 1% lidocaine (up to 1 mL) is injected at the skin entry site, which should be 1 to 2 cm cranial to the bony prominence of the distal radius. The radial artery is accessed by either a micropuncture needle (anterior wall technique) or a 20-gauge angiocatheter needle (posterior wall technique) at a 30- to 45-degree angle. With pulsatile blood return, a 0.018-inch guidewire is advanced into the artery, and there should be little or no resistance to wire advancement. If this were to be noted, access should be reexamined before proceeding. Otherwise, the needle is removed and the sheath is advanced over the wire into the artery. Once the sheath is in place, typically, 5000 units of unfractionated heparin are given as a bolus, or weight-adjusted (50 units per kg), to prevent postprocedural radial artery occlusion. Practices differ but one should consider smaller sizes for women (4 to 5F) yet larger sizes (6F, maximum 7F in men) if coronary intervention is likely. Overstretching of the artery is to be avoided as it leads to higher postprocedural occlusion rates. A longer sheath (up to 16 cm) has been considered to protect more against vasospasm at the level of the forearm. However, other studies suggest that it is the hydrophilic coating rather than the length of the sheath that reduces spasms. Arterial vasospasm is a complicating factor and prevented by adequate sedation, avoidance of limb cooling, and administration of vasodilators. Most commonly, nitroglycerin (100 to 200 mcg) and verapamil (2.5 mg) are given. Other approaches are sublingual nitroglycerin, and/or intra-arterial (local) administration of diltiazem or nicardipine. With these preparations, coronary angiographic catheters are advanced over a 0.035-inch floppy or small J-tipped guidewire into the ascending aorta and then manipulated to engage the coronary artery ostia. Some operators note catheter instability or poor coronary ostial engagement from the radial approach. Larger (>7F) sheath sizes that may be required for complex PCI also present a challenge for radial access.

After the procedure is completed, arterial puncture hemostasis is most often obtained with air-bladder compression bands or other similar closure devices ( Fig. 22.2 ). In addition to adequate initial anticoagulation, the use of “patent hemostasis” (occlusion to the point of bleeding control but not complete vessel occlusion) minimizes the risk of radial artery occlusion. Hematomas, while uncommon, can lead to pseudoaneurysms and very rarely compartment syndrome ( eFig. 22.1 ). Other risks include radial artery vasospasm, dissections, transient hand dysfunction, and potentially a higher risk of future coronary artery bypass graft (CABG) radial graft dysfunction.

Percutaneous Femoral Artery Technique

Femoral artery access was the standard access over the last four decades. Femoral artery access uses the Seldinger needle puncture technique with the insertion of a valved sheath (6 to 8F or larger) and use of preshaped “Judkins” catheters. The optimal puncture location is the common femoral artery (CFA). Familiarity with the anatomy will assist in identifying the point of needle entry, usually 1 to 3 cm below the inguinal ligament, in line with the palpable course of the CFA ( Figs. 22.3 and 22.4 ). Superficial anatomic landmarks such as the inguinal crease can be misleading in obese as well as very thin individuals. Identifying the inferior edge of the femoral head by fluoroscopy using a hemostatic clamp is used to begin the puncture. Ultrasound imaging provides the best visualization and definition of the vascular location ( Fig. 22.5 ) and has been shown to improve first-pass success rates and reduce vascular complications in general. Correct placement of the sheath in the CFA will reduce the chance of retroperitoneal hematoma (as occurs with puncture that are above the inferior epigastric artery) or pseudoaneurysm and arteriovenous fistula formation (as occurs with punctures below the profunda and superficial femoral artery bifurcation). Accidental cannulation of the superficial or profunda femoral artery may result in limb ischemia or inability to accommodate vascular closure devices.

Once localization of the vessel is completed, local anesthesia with 1% lidocaine is given and a small incision is performed followed by insertion of an 18- to 21-gauge needle into the CFA in a modified Seldinger technique ( Fig. 22.6 ). Upon pulsatile blood return, a 0.038-inch guidewire is advanced and should pass freely through the vessel. Symptoms of pain or excessive resistance on wire advancement may indicate vascular trauma, such as dissections or perforations, and should be recognized immediately. The advantages of the Judkins technique are the relative ease, speed, and reliability, and yet vigilance is still required to ensure quality and safety.

After the procedure, femoral hemostasis can be achieved with a vascular closure device or with manual compression. Despite their perceived benefit, vascular closure devices are not superior to manual compression in general and may in fact be inferior in patients who have had multiple vascular access needle attempts. Vascular closure devices do play an important role in cases of large-bore (>10F) access which are now common in the era of TAVR with sheath sizes of 18F to 24F. Femoral sheaths should not be removed until the activated clotting time (ACT) is less than 160 to 180 seconds unless a vascular closure device is being used.

Patients with a history of peripheral arterial disease (PAD) require particular attention. Before the procedure, one should carefully review what types of interventions were performed in the past (e.g., balloon angioplasty, patch endarterectomy, arterial conduits, and prosthetic grafts). The vascular anatomy should be defined for location and size such that large devices may be accommodated. Prosthetic peripheral vascular grafts are the most problematic vascular challenges, not because they cannot be cannulated but rather because of the lack of adequate closure and potential for thrombotic occlusion. For these reasons, these grafts are usually avoided. Complications arising from femoral access are outlined in eTable 22.3 .

Percutaneous Femoral Vein Access

Using the femoral arterial pulse as a landmark, the femoral vein sits approximately 1 cm medial to the femoral artery. If a combined arterial and venous access is needed, the entry skin area is infiltrated by lidocaine sufficient to cover both puncture sites. The venous puncture site is 0.5 to 1 cm medial and 0.5 to 1 cm caudal to the planned arterial entry site. Because venous pressure is low, a 10- or 20-mL syringe is attached to the Seldinger needle and gently aspirated during needle advancement. The operator inserts the needle through the skin at a 30- to 45-degree angle to the horizontal plane while palpating the femoral arterial pulse with light pressure so as to not occlude the vein. If arterial pulsations are felt at the tip of the needle, the needle is withdrawn and redirected at a slightly more medial angle. Ultrasound imaging guidance can improve successful cannulation and reduce accidental arterial puncture. Upon entry of the vein, venous (nonpulsatile) dark blood should flow easily into the syringe. If the vein has not been entered, the needle is withdrawn, flushed, and reintroduced in a slightly more lateral or medial direction. The remainder of the venous sheath placement is completed in the same fashion as described for the femoral arterial sheath insertion.

A vein that has been entered mistakenly during a femoral artery puncture attempt should be used only if the needle tip did not puncture both walls of the artery and go into the vein behind it. Placing a sheath through the artery into the vein may create an arteriovenous (AV) fistula or cause uncontrolled bleeding from a large hole in the posterior wall of the femoral artery.

After the procedure is completed, venous hemostasis can be achieved with light finger pressure applied over the vein as described for femoral artery sheath removal. Usually only 5 to 10 minutes of compression is needed to obtain adequate hemostasis.

Percutaneous Brachial Vein Access

In conjunction with radial artery catheterization, the brachial or antecubital vein may be considered for venous access for right-heart catheterization. Access to the antecubital vein can be obtained using a 20-gauge IV or ultrasound-guided needle puncture. Application of a tourniquet above the elbow will facilitate the identification of a suitable vein. A medial antecubital vein is preferable over a lateral antecubital vein to avoid the acute angulation of the cephalic vein system as it joins with the axillary vein in the shoulder. Before sheath insertion, administration of 1% lidocaine over the puncture site will reduce discomfort. The arm vein sheath size is usually 5F sheath but can be as large as 7F with a suitably sized balloon-tipped pulmonary artery (PA) catheter. Advancing the PA catheter is often straightforward, but if venous tortuosity or valve obstruction is present, the operator can facilitate advancement with an angioplasty guidewire or use an injection of saline to straighten and stiffen the catheter and expand the vein. The balloon should not be expanded until the catheter is in the subclavian system.

Percutaneous Internal Jugular Vein Access

The internal jugular (IJ) vein, especially the right IJ, is the preferred venous access given the anatomic ease and for prolonged placement of sheath or PA catheter ( Video 22.1 ). The IJ approach allows for greater patient comfort and lower infectious risk than a femoral approach, and is preferred over the subclavian approach because of reduced risk of pneumothorax. Use of a micropuncture kit with a 21-gauge needle and introducer will minimize inadvertent puncture of the carotid artery or lung. After entering the jugular vein, the micropuncture assembly can be exchanged for any larger sheath (e.g., 7F) for right-heart catheterization or right ventricular biopsy.

The internal jugular vein is located lateral to the carotid artery in the anatomic triangle of the two heads of the sternocleidomastoid muscle and the clavicle. For access, the patient is instructed to lie supine with the head turned 30 degrees to the contralateral side. Patients with low venous pressure may require leg elevation to increase venous filling volume. Routine use of ultrasound imaging facilitates localization of the IJ and can verify its patency. The use of ultrasound is recommended by national guidelines and reduces the overall risk of complications (carotid artery puncture, in particular) by 70%.