Pharmacological Modification of Ischemic Preconditioning During Percutaneous Transluminal Coronary Angioplasty

Abstract

In the progression of repetitive balloon inflations during percutaneous transluminal coronary angioplasty (PTCA), the heart becomes more tolerant to ischemia. The study reported here analyzed the effects of theophylline and nicorandil on this intriguing phenomenon. Twenty-one patients with stable angina pectoris due to a significant stenosis at the left anterior descending; artery were subjected to PTCA. The balloon was inflated twice for two minutes each with a three-minute reperfusion period. Theophyylline, an adenosine receptor antagonist, was intravenously administered (0.6mg/kg/hr) to six patients during PTCA (theophylline group). Nicorandil, a hybrid between nitrate and an ATP-sensitive potassium channel opener, was intravenously administered (6 mg/hr) to nine patients during PTCA (nicorandil group). The rest of the patients served as controls (ischemic preconditioning group, n = 6). Cardiac adaptation to the second ischemia was observed in the ischemic preconditioning group, judging from lactate metabolism and electrocardiography. In both the theophylline and nicorandil groups, the difference between the two ischemic events was abolished. In the nicorandil group, the severity of the first ischemia was less than that of the ischemic preconditioning group. In conclusion, signal transduction through the adenosine receptor and opening of the ATP-sensitive potassium channels might play key roles, interactively or independently, in the cardioprotection observed in the process of PTCA.