Effect of Long-Term Nitrate Treatment on Cardiac Events in Patients With Vasospastic Angina

Abstract

Nitrates have been widely used as anti-ischemic drugs in patients with vasospastic angina (VSA). However, the effect of long-term nitrate treatment on cardiac events in VSA patients remains unclear. Two-hundred and thirty-one patients with VSA who had not been receiving any antiischemic drugs, including calcium channel blockers (CCBs), nitrates, nicorandil, or any combination of these medications were prospectively enrolled in the present study. All patients had a positive acetylcholine provocation test with normal coronary angiograms, and they received CCBs after enrollment. They were divided into 2 groups based on whether nitrates were included in the treatment: a nitrate group (n=86) and a without nitrate group (n=145). The baseline clinical characteristics and frequency of anginal attacks within 48h before enrollment were similar between the 2 groups. With a median follow-up period of 70.5 months, 29 patients developed cardiac events, including 7 sudden cardiac deaths and 22 re-admissions for acute coronary syndrome. Cardiac events occurred in 19.8% of the nitrate group and in only 8.3% of the patients who were not taking nitrates (P=0.015). In a multivariate analysis, long-term nitrate treatment (hazard ratio 5.18, 95% confidence interval: 1.69-15.89, P=0.004) was an independent predictor of cardiac events. These data indicate that long-term nitrate treatment in addition to CCBs might not reduce cardiac events in VSA patients.