Clinical characteristics and current management of medically refractory unstable angina

Of 531 patients admitted to the Duke Coronary Care Unit with unstable angina (UA) from June 1981 to September 1982, 100 had persistent angina despite optimal medical therapy of nitrates, propranolol, and nifedipine. At catheterization, 70% of the refractory patients had left main (LM) or three-vessel disease (TVD), 68% had left ventricular end-diastolic pressures of greater than 12 mmHg, and 24% had ejection fractions (EF) of less than 0.40. Twenty-four patients were greater than 65 years of age, and 53 had associated major diseases. Forty-eight patients (Group I) had no evidence of myocardial infarction in the 30 days before catheterization, whereas 52 patients had an infarction precipitating the unstable angina within the preceding 30 days (Group II). Emergent coronary artery bypass grafting was performed in all 100 patients irrespective of ventricular function, hemodynamic status, or coronary anatomy. Management protocols included prompt surgical intervention, preoperative stabilization with the balloon pump in LM or TVD, meticulous myocardial protection, and complete coronary revascularization. An average of 3.6 grafts were placed in each patient. There were two hospital deaths in Group I, and two in Group II. Two-year survival was 90% in Group I and 88% in Group II, and 81% of surviving patients were NYHA Class I or II. Thus, refractory UA denotes particularly severe coronary disease with a high incidence of LM, TVD, and depressed EF. Baseline clinical characteristics, criteria for operation, and expected results in the postinfarction group seem to be similar to the unstable angina group in general. Cardiac anatomic and functional variables no longer constitute operative contraindications. Aggressive operative management is safe, and the current risk may be less dependent on coronary anatomy and ventricular function than previously appreciated.