Efficacy of diltiazem for medically refractory stable angina: long-term follow-up.

To assess the efficacy of long-term diltiazem therapy when added to beta blockers and nitrates, we prospectively studied patients with chronic exertional angina who were determined to have medically refractory angina pectoris which was too severe to enter placebo-controlled studies. The mean follow-up time was 24.6 months (8-47 months) and all patients were seen every 2-4 months. Angina frequency decreased from a prediltiazem frequency of 9.5 episodes per week (1-40 per week) to 3.3 attacks per week (0-21 per week) at 6 months and 3.3 attacks per week (0-40 per week) at the patients's last evaluation. Similar reductions in nitroglycerin consumption were reported. Five patients had an increase in angina frequency during the mean 24.6 months of follow-up, which necessitated coronary bypass surgery, 8, 10, 12, 19, and 23 months after study entry, respectively. Diltiazem daily dosage ranged from 120 to 480 mg/day, the mean daily dose was 298 mg/day. Twenty (65%) patients remained on beta-blocker therapy and 19 (61%) patients on nitrate therapy in an effort to achieve a completely pain-free state. New cardiovascular events were documented in 3 patients during the follow-up period, with one patient having an uncomplicated myocardial infarction at 6 months, one patient hospitalized for prolonged chest pain at 2 months, and one patient dying following cardioversion for unrelated atrial fibrillation at 14 months poststudy entry. Adverse effects were reported during 19 of the 354 patient visits, but no patient had to stop therapy because of these. Sinus bradycardia required reduction of beta-blocker dosage in three patients and prolonged PR interval was observed in two additional patients.(ABSTRACT TRUNCATED AT 250 WORDS)