Additive effects of nicorandil on coronary blood flow during continuous administration of nitroglycerin

OBJECTIVES We examined whether patients with ischemic heart disease (IHD) s hould be treated with nicorandil, an adenosine triphosphate-sensitive potas sium channel opener, in addition to the regular use of nitrates. BACKGROUND It has been reported that nicorandil possibly has additive effec ts on nitroglycerin (NTG) treatment for angina, but the mechanism is not cl ear. METHODS We directly measured anterograde coronary blood flow (CBF) with a D oppler guide wire to examine the effects of intravenous administration of N TG (0.3 mg) and nicorandil (6 mg) during continuous administration of NTG a t a sufficient dose (25 mug/min) in subjects with normal and stenotic coron ary arteries. RESULTS Additional systemic administration of NTG decreased anterograde CBF (normal -19.7%; stenotic -21.2%). In contrast, nicorandil increased antero grade CBF in both normal (54.6%) and stenotic (89.6%) coronary arteries, wi thout the coronary steal phenomenon. There was a tendency toward nicorandil -dilated diameters in the patients with stenotic arteries (P = 0.06). There were no effects of additional administration on pulmonary artery wedge pre ssure. There was no difference in changes in heart rate and mean aortic blo od pressure between NTG and nicorandil therapy. CONCLUSIONS These results suggest that in patients treated with nitrates, a dditional administration of nicorandil is more useful, in terms of increasi ng CBF, than additional administration of nitrates. Adjunctive use of nicor andil with nitrates may provide the further benefit of myocardial protectio n and may improve the prognosis of patients with IHD. (J Am Coil Cardiol 20 01,37:719 -25) (C) 2001 by the American College of Cardiology.