Persistent Angina

Abstract

Percutaneous coronary intervention (PCI) has not been shown to reduce mortality in patients with stable coronary artery disease (CAD). The long-term clinical success of PCI is defined as the persistent relief of signs and symptoms of myocardial ischemia for more than 6 months after the index procedure. Data from large trials investigating the use of PCI in patients with stable CAD show that angina is still experienced in a large number of patients one year after the procedure and that this proportion increases over time. These data are, however, largely from post-hoc analyses of studies powered to measure other end points. We conducted the first prospective study investigating the incidence of persistent angina and inducible ischemia in patients with stable CAD undergoing PCI rated as 'successful' by the interventional cardiologist, and present an interim analysis of data from 220 patients. The mean age of our patients was 65 years; they were mostly male, mildly obese, hypertensive and dyslipidemic. Most patients had single-vessel disease affecting the left anterior descending artery and received a drug-eluting stent, and all patients had a positive stress test before PCI. At the follow-up visit, which was performed within 4 weeks of the index procedure, 52% of patients still had a positive stress test. Before PCI, 66% of patients reported experiencing angina on exertion. At the follow-up visit, one-third of those patients were still experiencing angina. Patients experiencing persistent angina (21% of the study population) graded their symptoms as improved (66%), unchanged (33%) or worsened (1%) after the procedure. We hypothesize that coronary microvascular dysfunction is a possible cause of persistent angina in this highly select group of patients. Risk factors for microvascular dysfunction include dyslipidemia, smoking and diabetes. It is currently difficult to dissect the relative contributions of coronary artery stenosis and microvascular dysfunction in precipitating myocardial ischemia. A better understanding of these mechanisms could reduce the number of unnecessary PCI procedures. Moreover, treatment options in patients who continue to experience angina despite 'optimal' medical therapy and 'successful' PCI are urgently required.