Chronic total occlusions

21.1

Planning

Planning is key for the success and safety of CTO PCI. The key indication for CTO PCI is symptom improvement . To allow adequate time for procedural planning and preparation and for proper counseling of patients, ad hoc CTO PCI is discouraged in most cases . CTO PCI preplanning can also help minimize contrast and radiation dose, reduce patient and operator fatigue, allow additional evaluation (such as myocardial viability) to be performed, and enable detailed discussion with the patient about all aspects of the CTO PCI procedure.

Coronary computed tomography angiography (CCTA) can be useful for evaluating the CTO segment and planning PCI. Several CCTA-based scores have been developed, such as the CT-RECTOR multicenter registry (Computed Tomography Registry of CTO revascularization) score and the Korean Multicenter CTO CT Registry score . CCTA can also help identify the optimal fluoroscopic projection angles with the least foreshortening to use during CTO crossing attempts ( Fig. 21.1 ).

In selected cases, however, ad hoc PCI may be the best option, such as in patients who present with an acute coronary syndrome due to failure of a highly diseased saphenous vein graft. In such patients treatment of the native coronary artery CTO is preferred, if feasible ( Section 18.7 ) . Another possible scenario is patients in whom obtaining arterial access is very challenging.

21.2

Monitoring

CTO PCI can be technically challenging and time consuming, and may require high radiation and contrast doses. Careful attention to the patient’s ECG and hemodynamics, as well as radiation and contrast use, is needed throughout the case. Moreover, the operators should be ready to manage any complication that may occur, such as perforation.

21.3

Medications

• Unfractionated heparin is the preferred agent, because it can be reversed in case of severe perforation. The recommended activated clotting times (ACT) are:

  • >300 seconds (Hemochron) for antegrade CTO PCI (some operators use >250 s).

  • >350 seconds (Hemochron) for retrograde CTO PCI (some operators use >300 s but check ACT very frequently if it is in the low 300s range).

• The ACT should be checked every 20–30 minutes once therapeutic.

• Bivalirudin is best avoided because its anticoagulant effect cannot be reversed. Moreover, there are unpublished cases in which guide thrombosis occurred during long procedures.

• Glycoprotein IIb/IIIa inhibitors and cangrelor should NOT be given, even after successful crossing and stenting of the CTO, because minor wire perforations could reopen and cause delayed pericardial effusion and tamponade.

21.4

Arterial access

CTO PCI is unique in that dual (or sometimes triple) arterial access is commonly required to allow dual angiography (see angiography section below). Both femoral and wrist access (proximal radial, distal radial , and ulnar) can be used, with use of radial access, including biradial access , significantly increasing in recent years . Use of distal radial access ( Section 4.3.2 ) or use of long radial artery sheaths may facilitate use of the left radial artery for CTO PCI. However, many operators still utilize at least one femoral access (often with 45 cm long sheaths) to increase guide catheter support.

21.5

Engagement

Vessel engagement is performed as outlined in Chapter 5: Coronary and Graft Engagement . Use of large (7 or 8 French) guide catheters with supportive shapes (AL for the right coronary artery and EBU or XB for the left main) are particularly important in CTO PCI, since strong support is often required to cross the CTO. Using 6 French guide catheters may limit the option of using IVUS-guided cap penetration or management of subsequent complications.

21.6

Angiography

A key difference of CTO PCI compared with non-CTO PCI is that in most cases it requires dual injection for better understanding of the CTO anatomy and guiding CTO crossing attempts. Dual injection angiography is the simplest and most effective technique for increasing CTO PCI success rates and should be performed in all patients with contralateral collaterals . It also improves procedural safety by elucidating the guidewire location during crossing attempts and facilitating management of periprocedural complications, such as perforation .

The following four characteristics need to be assessed for every CTO: (1) proximal cap morphology, (2) occlusion length, course, and composition (e.g., calcium), (3) quality of the distal vessel, and (4) characteristics of the collateral circulation ( Fig. 21.2 ).