Relation of therapeutic response to nifedipine to coronary anatomy and motion of S-T segment during unstable angina pectoris

Of 77 patients hospitalized for unstable angina pectoris and failure of oral, dermal, or intravenous nitrates and/or beta blockade, 81 percent with negligible or single-vessel disease and 55 percent with two- or three-vessel disease showed response (p < 0.05) to nifedipine therapy. Patients with either S-T elevation or no change during pain responded better (31 of 45) than those with any S-T depression (16 of 32; p < 0.05). Patients with negligible or singlevessel disease had a higher prevalence of S-T elevation ( 13 of 16) than patients with two- or three-vessel disease (15 of 31; p = 0.004). S-T motion did not predict response in patients with two- or three-vessel disease, but did predict response in patients with negligible or single-vessel disease. On follow-up study at 9 ± 8 (range one to 33) months, 39 of 42 who had shown response were free from pain. Three died from infarction without unstable angina. Five who showed response had elective bypass surgery. The addition of nifedipine abolished or reduced pain episodes by more than 50 percent in 61 percent of patients with refractory unstable angina pectoris. Patients with negligible or single-vessel disease with S-T elevation benefit most. In patients with two- or three-vessel disease, the type of S-T motion did not predict response. Follow-up of all those with response indicated sustained amelioration by nifedipine therapy. Failure of nifedipine therapy should not be accepted until a dose of 120 mg per day has been achieved, or until intolerable side effects appear.