Prognostic effects of calcium channel blockers in patients with vasospastic angina: A meta-analysis

Background: Although calcium channel blockers (CCB) are highly effective for suppression of vasospastic angina (VSA) attacks, their prognostic effects in VSA patients remain to be examined in a large number of patients. Methods and Results: Databases for related papers were searched and then a meta-analysis regarding the effects of CCB on major adverse cardiovascular events (MACE) in Japanese VSA patients with the 4 previous studies was performed. A total of 1,997 patients with positive coronary spasm provocation tests were evaluated. They were treated with either alone or combination of benidipine (n=320), amlodipine (n=308), nifedipine (n=182) or diltiazem (n=960). MACE were observed in 143 patients (cardiac death: 36, myocardial infarction: 51, heart failure: 26, stroke: 65, and aortic aneurysm: 11). The hazard ratio for the occurrence of MACE was significantly lower in patients treated with benidipine than in those with diltiazem. There was no significant difference in the clinical characteristics affecting the occurrence of MACE among the 4 CCB groups. Furthermore, the hazard ratio for the occurrence of MACE was significantly lower in those treated with benidipine, even after correction for patient characteristics that could have affected the occurrence of MACE (hazard ratio 0.41, P=0.016). Conclusions: These results suggest that among the 4 major CCB that effectively suppress VSA attacks in general, benidipine showed significantly more beneficial prognostic effects than others.