An Evidence Based Analysis of Percutaneous Coronary Intervention (PCI)

Percutaneous coronary intervention (PCI) is a non-surgical, invasive procedure with a goal to relieve the narrowing or occlusion of the coronary artery and improve blood supply to the ischemic tissue. This is usually achieved by different methods, the most common being ballooning the narrow segment or deploying a stent to keep the artery open.

PCI remains the mainstay treatment for acute cardiac ischemia. The indications for PCI include Stable Ischemic Heart Disease, STEMI and NSTEMI. The procedure involves the use of a guided catheter steered to the site of coronary arterial blockage, followed by dilation of the balloon at its end to remove the blockage and placement of a stent to maintain the patency. The choice of stent varies from case to case. Certain alternatives and adjuvant therapies are incorporated in order to adapt to specific scenarios. Complications can arise, which may require operative intervention. Mortality rate associated with the procedure is affected by the age and gender of the patient.

        More than 1.2 million percutaneous coronary interventions (PCIs) are performed annually in the United States. Despite the fact that more women than men die from cardiovascular disease in the United States, and despite the established benefits of PCI in reducing fatal and nonfatal ischemic complications in patients with acute myocardial infarction and high-risk acute coronary syndromes, only an estimated 33% of annual PCIs are performed in women. In addition, women experience greater delays to intervention and are referred for diagnostic catheterization less frequently than are men. Although suggested reasons for referral differences have included women’s older age at presentation, greater risk profile, and increased risk for an adverse procedural outcome, as well as differences in symptoms and pain perception between men and women and lower predictive accuracy of noninvasive testing in women, some evidence suggests a potential sex and race bias. In contrast, once women are referred for cardiac catheterization, revascularization rates and practices are similar to those in men.

The purpose of this statement is to review what is known and not known about PCI in women and to put published data in context with contemporary coronary intervention. It is not the intention of the writing group to give specific treatment recommendations but rather to compile and collate the available sex-specific data on the safety and efficacy of interventional therapies in women.

The adverse outcomes of women undergoing PCI, including the rates of short- and long-term mortality, nonfatal myocardial infarction (MI), and emergency coronary bypass surgery, have decreased significantly over time with contemporary interventional therapies. 

Vascular complications (such as access-site hematomas, bleeding complications requiring transfusion, and retroperitoneal bleeds) have improved over time in women with the development of less aggressive anticoagulation regimens, increasing use of weight-adjusted heparin dosing, and introduction of smaller sheath sizes and early sheath removal. Nevertheless, women still have a 1.5- to 4-times higher risk of vascular complications as compared with men, and female sex is an important contributing factor.

Interventional Treatment of STEMI in Women

The overall superiority of primary PCI over fibrinolytic therapy has been clearly demonstrated for women. A relative risk reduction that is similar for men and women translates to a larger absolute benefit for women because they have higher risk profiles. An estimated 56 deaths could be prevented for every 1000 women treated with primary PCI rather than fibrinolytic therapy, as compared with 42 fewer deaths per 1000 men.

Shock

Female sex is an independent risk factor for the development of cardiogenic shock complicating acute MI. Age is an additional risk factor for the development of these complications, such that older women are at substantial risk of cardiogenic shock. Once shock develops, however, female sex is not independently related to outcome.

There remain significant challenges of fine tuning these bioabsorbable scaffolds to match the initial performance and handling characteristics of conventional metallic stents, with scaffold deliverability in tortuous and calcified vessels potentially presenting a major concern. Furthermore, It remains to be demonstrated whether bioabsorbable scaffolds can truly restore vascular integrity and function and the results of ongoing trials are eagerly awaited.

PCI is a common invasive procedure with a relatively low complication rate. However, when complications do occur, operators may be unprepared to manage them. Uncertainty about complication management could contribute to the undertreatment of patients with high-complexity, high-risk coronary disease. Complication management requires preparation, early recognition and broad differential diagnosis, knowledge of effective techniques, team-based communication strategies, and multi-disciplinary collaboration.