THE EFFECTS OF INTRACORONARY ADENOSINE ON PRECONDITIONING DURING CORONARY ANGIOPLASTY

There is evidence that the first balloon inflation during coronary ang ioplasty provides a preconditioning stimulus leading to decreased isch emia during subsequent balloon inflations. Endogenous adenosine releas e may play a role in ischemic preconditioning. Therefore, intracoronar y adenosine administration prior to the first balloon inflation during percutaneous transluminal coronary angioplasty (PTCA) might modify th e preconditioning response to the first balloon inflation. Forty-one p atients underwent double-blind randomization to treatment with 100 meg of intracoronary adenosine or placebo prior to coronary angioplasty. Twenty patients (11 adenosine, 9 placebo) had complete resolution of i schemia between inflations allowing comparison between the first and s econd inflation. An angioplasty guidewire was used to obtain an intrac oronary electrocardiogram. The mean reduction in ST elevation during t he second inflation compared with the first was 4.8 mm in the placebo group and -0.8 in the adenosine group (p < 0.05 placebo vs. adenosine) . Seven of 9 placebo patients had a decrease in ischemia during the se cond inflation compared with the first, while only 2 of 11 adenosine p atients showed a reduction. It was concluded that (1) the first inflat ion during PTCA is a preconditioning stimulus leading to a decrease in ischemia during later inflations, and (2) intracoronary adenosine adm inistration prior to PTCA modifies the preconditioning effect of the f irst inflation. These data suggest that adenosine plays a role in isch emic preconditioning in humans.