Abstract
The human heart progressively becomes more tolerant to ischemia after repeated balloon inflations during percutaneous transluminal coronary angioplasty (PTCA). The present study investigated whether nicorandil, a hybrid between nitrate and an ATP-sensitive potassium channel opener, affects this ischemic preconditioning. Sixteen patients with stable angina pectoris caused by left anterior descending artery lesions were subjected to 2 balloon inflations of 2-min duration with a 3-min reperfusion period. Seven of these patients served as the control group and in the remaining 9 patients, nicorandil was administered intravenously (6 mg/h) throughout the PTCA procedure (nicorandil group). The lactate extraction ratio (LER) was obtained at 30 s after each ischemic event (LERpost-1 and LERpost-2) in both groups. In the control group, LERpost-1 was more negative than LERpost-2 (-185.7±74.2 vs -98.0±37.3%, p<0.01). The ratio of the sum of the ST elevation in the precordial leads during the second inflation (ΣST-2, 0.94±0.66 mV) to that during the first inflation (ΣST-1, 1.43±1.17 mV) was 0.72±0.16 in the control group, which was less than the ratio in the nicorandil group (1.06±0.13, p<0.01). Nicorandil abolished the difference between the 2 ischemic events (LERpost-1, -45.1±41.6 vs LERpost-2, -43.5±51.1%; ΣST-1, 1.38±0.80 vs ΣST-2, 1.46±0.90 mV). LER was less negative in the nicorandil group than that in the control group (LERpost-1, -45.1±41.6 vs -185.7±74.2%, p<0.01; LERpost-2, -43.5±51.1 vs -98.0±37.3%, p<0.05). Thus, nicorandil improved lactate metabolism during PTCA without significantly influencing ST-elevation. In conclusion, intravenous pre-administration of nicorandil appears to precondition the human heart during PTCA. (Jpn Circ J 2001; 65: 526 - 530)
