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A randomized study comparing propranolol and diltiazem in the treatment of unstable angina
Insights
Diltiazem and propranolol effectively reduced chest pain in unstable angina patients. This suggests diltiazem is a viable alternative to beta-blockers, and coronary spasm may not be the primary cause of unstable angina.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Unstable angina is a critical condition requiring effective treatment.
- Identifying alternative therapies to beta-receptor blocking agents is important for patient management.
Purpose of the Study:
- To compare the efficacy of diltiazem and propranolol in treating unstable angina.
- To investigate the role of coronary artery spasm in unstable angina.
Main Methods:
- 100 unstable angina patients (excluding Prinzmetal's variant angina) were randomized to diltiazem or propranolol.
- Chest pain episodes, left ventricular function, and coronary artery disease extent were assessed.
- Outcomes including symptom-free status, death, myocardial infarction, and need for bypass surgery were monitored.
Main Results:
- Both diltiazem and propranolol significantly reduced daily chest pain episodes.
- Symptom relief and long-term outcomes (death, myocardial infarction, bypass surgery) were similar between the two groups.
- Only 15 patients were symptom-free at mean 5.1-month follow-up.
Conclusions:
- Diltiazem is a potential alternative to beta-receptor blocking drugs for unstable angina.
- Coronary artery spasm may not be the primary driver of unstable angina when Prinzmetal's variant is excluded.
Abstract:
One hundred consecutive patients hospitalized in the coronary care unit for unstable angina, excluding patients with Prinzmetal's variant angina, were randomized within 24 hours of admission to treatment with diltiazem (50 patients) or propranolol (50 patients). Also excluded were patients with previous coronary artery bypass surgery and those receiving a beta-receptor blocking agent at the time of hospital admission. Left ventricular function and the extent of coronary artery disease were similar in the two groups. During the hospital stay, the number of chest pain episodes decreased from a mean (+/- SD) of 0.75 +/- 0.1 per patient per day to 0.26 +/- 0.07 (p less than 0.05) with diltiazem and 0.29 +/- 0.1 (p less than 0.05) with propranolol therapy. The circadian distribution of chest pain episodes was affected similarly. After 1 month, 14 of the patients treated with diltiazem were symptom-free compared with 13 treated with propranolol. At a mean follow-up time of 5.1 months (range 1 to 15), death had occurred in two patients in each group and myocardial infarction in five diltiazem- and four propranolol-treated patients (difference not significant). Coronary artery bypass surgery had been performed in 21 diltiazem- and 19 propranolol-treated patients (difference not significant). Only 15 patients were symptom-free, 9 treated with diltiazem and 6 with propranolol. This similar result observed with the two forms of treatment suggests that coronary artery spasm may not be the main factor involved in unstable angina when Prinzmetal's variant angina is excluded. It also suggests that diltiazem can be used as an alternative to the usual treatment with beta-receptor blocking drugs.