Prognostic Impact of Chronic Vasodilator Therapy in Patients With Vasospastic Angina

BACKGROUND: Chronic vasodilator therapy with long-acting nitrate is frequently used to treat vasospastic angina. However, the clinical benefits of this approach are controversial. We investigated the prognostic impact of vasodilator therapy in patients with vasospastic angina from the multicenter, prospective VA-KOREA (Vasospastic Angina in KOREA) registry. METHODS AND RESULTS: We analyzed data from 1895 patients with positive intracoronary ergonovine provocation test results. The patients were divided into 4 groups: no vasodilator (n=359), nonnitrate vasodilator (n=1187), conventional nitrate (n=209), and a combination of conventional nitrate and other vasodilators (n=140). The primary end point was a composite of cardiac death, acute coronary syndrome, and new-onset arrhythmia at 2 years. Secondary end points were the individual components of the primary end point, all-cause death, and rehospitalization due to recurrent angina. The groups did not differ in terms of the risk of the primary end point. However, the acute coronary syndrome risk was significantly higher in the conventional nitrate (hazard ratio [HR], 2.49; 95% CI, 1.01–6.14; P=0.047) and combination groups (HR, 3.34; 95% CI, 1.15–9.75, P=0.027) compared with the no-vasodilator group, as assessed using the inverse probability of treatment weights. Subgroup analyses revealed prominent adverse effects of nitrate in patients with an intermediate positive ergonovine provocation test result and in those with low Japanese Coronary Spasm Association scores. CONCLUSIONS: Long-acting nitrate-based chronic vasodilator therapy was associated with an increased 2-year risk of acute coronary syndrome in patients with vasospastic angina, especially in low-risk patients.