Nicorandil, a hybrid between nitrate and ATP-sensitive potassium channel opener, preconditions human heart to ischemia during percutaneous transluminal coronary angioplasty

The human heart progressively becomes more tolerant to ischemia after repea ted balloon inflations during percutaneous transluminal coronary angioplast y (PTCA). The present study investigated whether nicorandil, a hybrid betwe en nitrate and an ATP-sensitive potassium channel opener, affects this isch emic preconditioning. Sixteen patients with stable angina pectoris caused b y left anterior descending artery lesions were subjected to 2 balloon infla tions of 2-min duration with a 3-min reperfusion period. Seven of these pat ients served as the control group and in the remaining 9 patients, nicorand il was administered intravenously (6 mg/h) throughout the PTCA procedure (n icorandil group). The lactate extraction ratio (LER) was obtained at 30s af ter each ischemic event (LERpost-1 and LERpost-2) in both groups. In the co ntrol group, LERpost-1 was more negative than LERpost-2 (-185.7 +/- 74.2 vs -98 +/- 37.3%, p < 0.01). The ratio of the sum of the ST elevation in the precordial leads during the second inflation (<Sigma>ST-2, 0.94 +/- 0.66 mV ) to that during the first inflation (Sigma ST-1, 1.43 +/- 1.17 mV) was 0.7 2 +/- 0.16 in the control group; which was less than the ratio in the nicor andil group (1.06 +/- 0.13, p < 0.01). Nicorandil abolished the difference between the 2 ischemic events (LERpost-1, -45.1 <plus/minus> 41.6 vs LERpos t-2, -43.5 +/- 51.1%; Sigma ST-1, 1.38 +/- 0.80 vs Sigma ST-2, 1.46 +/- 0.9 0 mV). LER was less negative in the nicorandil group than that in the contr ol group (LERpost-1, -45.1 +/- 41.6 vs -185.7 +/- 74.2%, p < 0.01; LERpost- 2, -43.5 <plus/minus> 51.1 vs -98.0 +/- 37.3%, p < 0.05). Thus, nicorandil improved lactate metabolism during PTCA without significantly influencing S T-elevation In conclusion, intravenous pre-administration of nicorandil app ears to precondition the human heart during PTCA.