The American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions (ACC/AHA/SCAI) task force provides broad guidelines and recommendations for appropriate application of PCI technology based on scientific evidence for revascularization. Recommendations for revascularization with PCI include patients presenting with significant ischemia on noninvasive testing, unstable angina, and acute coronary syndrome (ACS). When the patient is considered for revascularization with PCI, the potential risks and benefits should be discussed in detail with the patient and family and be weighed against alternative therapies such as medical therapy or coronary artery bypass graft (CABG) surgery. Patients should understand the possible complications associated with the procedure, the possibility of restenosis, stent thrombosis (see complications) postprocedure, and the potential for incomplete revascularization in patients with diffuse coronary artery disease (CAD). The clinical and angiographic variables associated with increased mortality include advanced age, female sex, diabetes mellitus, prior myocardial infarction (MI), multivessel disease, left main disease or equivalent (severe stenosis of the left anterior descending artery and circumflex arteries proximal to any major branch), a large area of myocardium at risk, pre-existing impairment of left ventricular (LV) function or renal function, and collateral vessels supplying significant areas of myocardium that originate distal to the segment to be treated.³

ACC/AHA/SCAI⁴ recommends an early invasive strategy with PCI in patients with unstable angina/non-ST-elevation MI (NSTEMI) who exhibit the following:

In patients with stable CAD optimal medical therapy alone can be considered versus PCI with optimal medical therapy. PCI when added to optimal medical therapy in stable angina has been shown to reduce the prevalence of angina symptoms but not to reduce long-term rates of death, MI, or hospitalization for ACS.⁵

Dotter and Judkins first proposed the concept of transluminal angioplasty in 1964.¹⁵ Gruentzig initially applied the technique of percutaneous transluminal coronary angioplasty (PTCA) to human coronary arteries in 1977.¹ Since the first PTCA, advances in catheter and balloon techniques have improved immediate and long-term success. Although conventional balloon angioplasty is a core procedure in the catheterization laboratory, it is usually not a stand-alone procedure but is now augmented by adjunctive stenting, which greatly improves procedural success and reduces complication rates.

The desired therapeutic effect of balloon angioplasty is the enlargement of the internal luminal diameter of the diseased artery. Application of balloon pressure to an atherosclerotic lesion results in plaque rupture, disruption of the endothelium, and stretching of the vessel segment, which enlarges the vessel lumen size (Fig. 23-1).

Guiding catheters are used to cannulate the coronary artery and to provide support for delivery of guidewires and interventional devices. In the catheterization laboratory, after the guide catheter is placed and the wire crosses the lesion, a balloon catheter is selected that most closely approximates the diameter of the nondiseased reference segment adjacent to the site to be treated. The prepared and flushed balloon is loaded onto the free end of the guidewire. The balloon is passed into the guide catheter, down the proximal vessel, and across the lesion. Once the balloon catheter is positioned across the lesion, the balloon is inflated using a handheld inflation device equipped with a pressure dial. Multiple balloon inflations of variable pressure and duration are used depending on the type of lesion and the physician preference. The response of the lesion to dilatation is assessed by contrast injection and repeat angiography through the guiding catheter with the guidewire in place. When the lesion in successfully dilated, the balloon apparatus is removed and multiple angiographic projections are reviewed. The guidewire and guiding catheter are removed after an adequate result is obtained.

Coronary atherectomy (directional and rotational) and excimer laser coronary angioplasty (ELCA) were developed and approved by the FDA for coronary artery use in the late 1980 to 1990s, with hopes of resolving the limitations of PTCA. Atherectomy device technique involves reduction of the severity of coronary blockage by removal of atheromatous plaque rather than compressing and/or fracturing the plaque, or stretching the arterial wall. In theory, this approach was developed to permit a more controlled vascular injury, minimize the degree of arterial mural stretch, create a smoother surface by debulking the vessel, and removal of atherosclerotic plaque that is frequently resistant to balloon dilatation.

Atherectomy devices have been used successfully to remove atherosclerotic plaque but were associated with increased complication rates and restenosis rates similar to PTCA from neointimal hyperplasia. Atherectomy devices now account for less than 3% of current PCI and are being used in very specific subsets of patients. Clinical trials have shown no improvement in long-term results with these devices; many atherectomy devices no longer are used.¹⁸,¹⁹

The majority of current PCI involve coronary stenting as a primary procedure or as an adjunct to balloon angioplasty. When PTCA was first introduced, it was plagued by two major limitations: acute or subacute closure, and restenosis. Subsequently, improved intracoronary stent design, techniques, and pharmacological management have contributed to the success of catheter-based revascularization with stents, reducing the incidence of these two major complications
of PCI. The optimal stent should be easily and safely deliverable to various locations in coronary arteries and have the following properties: are flexible, low profile, radiopaque, smooth contour, sufficient radial strength, and tissue and blood compatible.²⁷

Dotter first demonstrated the concept of stenting an injured vessel in 1960s. In 1986, Sigwart et al.28 reported use of a percutaneous, self-expanding metallic stent in coronary vessels in humans. The development of intracoronary stents was initiated to provide structural support to an artery opposing elastic recoil preventing vasoconstriction, and preventing or treating dissections of the arterial wall seen with other coronary devices. The stent procedure is similar in preparation to PTCA with a guide catheter in the ostium of the coronary artery and a guidewire passed across the lesion. The lesion can be predilated with an angioplasty balloon or the stent placed without predilatation (primary stenting).

There are a variety of different types of intracoronary stents, categorized by mechanism of deployment, structure, metals, sizes, and stent coating (including bare-metal, drug-eluting, and covered). Stents are deployed using balloon-expandable or self-expandable mechanisms. The most commonly used stents are balloon-expandable and delivered over a guidewire into the coronary artery in a collapsed state and mounted on a balloon delivery system. Self-mounted stents are available in Europe. Once the balloon is positioned correctly across the lesion, the balloon is inflated, expanding the stent. The balloon delivery system is removed and a high-pressure balloon is frequently used to postdilate the stent to assure its full expansion (Fig. 23-4). Adequate apposition of the stent to the arterial wall has been found to be very important for long-term success and reduction of major cardiac events secondary to thrombotic complications. The self-expanding stents are used less frequently in the coronary arteries and more frequently in the peripheral vasculature. They are placed on the delivery system in a collapsed state with a retaining outer membrane. Retraction of the membrane after the delivery system is across the lesion allows the stent to expand. A high-pressure balloon can be used after deployment to completely expand the stent.