9 Difficult Subsets for Percutaneous Coronary Interventions Calcific Vessels, Coronary Bypass Conduits, Elderly Patients, and Cardiac Transplantation

Nauman Siddiqi, William H. Suh, Barry F. Uretsky, Ahmad Edris, Mohammad Marashdeh, Todd K. Zynda, Morton J. Kern

Specific anatomic subsets require preparation and a game plan to deal with the potential problems resulting in a suboptimal result or failed procedure. A complication, even during the most straightforward procedure, should always be anticipated. The key to overcoming difficult percutaneous coronary intervention (PCI) is planning and anticipation of problems. No operator should begin a procedure without having mentally performed all the necessary steps and having visualized the optimal result.

As the first step, the operator should assess the need for “support” for guide catheter seating. Reviewing the diagnostic images will provide an estimate of the degree of difficulty in both seating and stabilizing the guide catheter. Guide catheter diameter selection is also important as certain cases, for example, bifurcation stenting, require a larger guide, typically 7 F or 8 F. Appreciation of the tortuosity, calcification, and angulation of the target lesion origin will also contribute to the shape and diameter of the guide catheter.

Second, a working knowledge of multiple guidewires and their capabilities in different circumstances is an important prerequisite in performing a smooth procedure. It is not unusual to use multiple PCI guidewires in a trial-and-error fashion before achieving the final result. However, a clear guidewire plan should be developed before starting the procedure. Difficulties in guidewire, balloon, and stent advancement may dictate the use of a second or “buddy” wire of some stiffness, or the use of a deep-seated guide position, to accomplish the task.

Finally, concern about the patient’s tolerance for ischemia and hemodynamic stability must be included in planning. The operator may opt for an additional arterial and/or venous access for possible intra-aortic balloon pumping or left ventricular assist support (e.g., Impella catheter) or temporary pacemaker placement.

This chapter will review common approaches to several difficult PCI situations. Because many cases of difficult PCI also involve situations of high or extreme risk, further discussion of these patients is provided in more detail in the following chapters. Chronic total occlusion PCI, ostial, and unprotected left main stenting are addressed in subsequent chapters.

Severely Calcified Stenoses

Balloon angioplasty of heavily calcified stenoses stretches the noncalcified vessel wall, promoting dissection (or [rarely] rupture) originating at the border region of the calcified and elastic regions of the stenosis. Severe calcification is associated with reduced primary success rates and increased complications. Because PCI of calcified lesions often requires high-pressure inflations (>15 atm), noncompliant balloon catheters are preferred. However, heavily calcified lesions may puncture polyethylene terephthalate balloon material. Removal of a ruptured and entrapped balloon can be difficult. In calcific lesions, direct stenting without balloon dilation is not recommended since it may result in incomplete stent deployment and a potentially ruptured and entrapped balloon catheter.

Rotational atherectomy (Rotablator, see Chapter 6) may be used primarily in this type of lesion, particularly in view of the increased complications and dissection rates from balloon angioplasty. The value of the Flextome Cutting Balloon (Boston Scientific Corporation, Natick, MA) or the AngioSculpt Balloon (Vascular Solutions, Minneapolis, MN) is less certain in this setting.