PRECONDITIONING OF HUMAN MYOCARDIUM WITH ADENOSINE DURING CORONARY ANGIOPLASTY

Background It is unknown whether adenosine can precondition human myoc ardium against ischemia in vivo. Methods and Results Thirty patients w ere randomized to receive a 10-minute intracoronary infusion of adenos ine (2 mg/min) or normal saline; 10 minutes later, they underwent perc utaneous transluminal coronary angioplasty (PTCA; three 2-minute ballo on inflations 5 minutes apart). In control patients, the ST-segment sh ift on the intracoronary ECG was significantly greater during the firs t inflation than during the second and third inflations, consistent wi th ischemic preconditioning. In contrast, in adenosine-treated patient s, there were no differences in ST-segment shift during the three infl ations. The ST-segment shift was significantly smaller in the adenosin e-treated group compared with the control group during all three infla tions. The reduction in ST-segment shift afforded by adenosine during the first inflation (-72% versus first inflation in control subjects) was greater than that afforded by ischemic preconditioning in control subjects (-52% during the third versus first inflation). Measurements of chest pain score paralleled those of ST-segment shift. Adenosine ha d no effect on baseline regional wall motion as determined by quantita tive two-dimensional echocardiography. Thus, intracoronary infusion of adenosine before PTCA rendered the myocardium remarkably resistant to subsequent ischemia. Judging from the intracoronary EGG, the protecti on provided by adenosine was even superior to that provided in control subjects by the ischemia associated with the first two balloon inflat ions. Infusion of adenosine had no major adverse effects in patients u ndergoing PTCA of the left anterior descending or circumflex arteries. Conclusions Adenosine preconditions human myocardium against ischemia in vivo. Pretreatment with adenosine is remarkably effective (even mo re effective than ischemic preconditioning) and could be used prophyla ctically to attenuate ischemia in selected patients undergoing PTCA of the left anterior descending coronary artery. Whether adenosine can b e safely infused into the right or the circumflex coronary artery in t he presence of a temporary pacemaker remains to be established.