Effect of nitroglycerin and nicorandil on regional poststenotic quantitative coronary blood flow in coronary artery disease: A combined digital quantitative angiographic and intracoronary Doppler study

Little information is available concerning the effects of nitrates and pota ssium channel openers on local poststenotic blood flow in coronary artery d isease (CAD). Combined quantitative digital angiography (QCA) and intracoro nary Doppler (IVADO) velocity measurements were used to determine changes i n absolute poststenotic blood flow after intracoronary injection of 0.2 mg nitroglycerin and 0.5 mg nicorandil. Quantitative blood now (QBF) was calcu lated from average peak-flow velocity (APV) and angiographic cross-sectiona l area (CSA): QBF (ml/min) = CSA x APV x 0.5. In group 1 (n = 9), 0.5 mg ni corandil i.c. was identified as optimal to achieve maximal vasodilatation. In patients with CAD (group II, n = 12), i.c. injection of 0.5 mg nicorandi l induced a significant increase in poststenotic CSA (+38%) and QBF (+50%). In contrast, 0.2 mg nitroglycerin (group III, n = 12) increases poststenot ic CSA (+38%) without a significant change in QBF (+23%). Additional applic ation of nicorandil in these patients induced further significant increases in CSA (+55%) and QBF (+48%) compared with baseline. There were no signifi cant changes in stenosis area, Poststenotic blood flow can be increased by nicorandil after application of nitroglycerin. This effect is most likely m ediated by the potassium channel-opening effect of nicorandil, Combined use of QCA and IVADO is a unique approach to measure local poststenotic QBF in patients with CAD.