923-6 Intravenous Adenosine and Lidocaine to Limit Reperfusion Injury During Acute Myocardial Infarction: Preliminary Data

Abstract

Adenosine (ADO) and lidocaine (LDO) given prior to restoration of blood flow reduces reperfusion injury in animals. We conducted a pilot study of intravenous ADO and LDO in pts undergoing direct angioplasty for acute myocardial infarction (AMI). Pts with ≤ 12 hours of chest pain and electrocardiographic evidence of AMI were given LDO 1 mg/kg iv bolus and 2 mg/min iv infusion beginning at the time of recruitment, and ADO 70 mcg/kg iv infusion beginning when coronary occlusion (TIMI grade 0 – 1 blood flow) was confirmed angiographically. Pts with bronchospasm, blood pressure < 100 mmHg, or < 1° heart block were excluded. ADO and LDO were given for 1 hour after vessel patency was restored. Myocardial area at risk and final infarction area were measured with serial Tc-99m-sestamibi perfusion studies (prior to angioplasty, before hospital discharge and 6 weeks after discharge). A salvage index (S1) was constructed by correcting the change in sestamibi perfusion defect for the mass of myocardium at risk. Analysis of 25 patients completing the protocol revealed a mean ( ± SD) salvage of 20 ± 17% and S1 = 0.55. Salvage and S1 were 25 ± 18% and 0.54 for anterior infarctions, 13 ± 5% and 0.57 for inferior infarctions, respectively. These data were compared to an historical control group consisting of 50 patients undergoing direct angioplasty for AMI without adjunctive ADO/LDO. After adjustment for time to treatment and perfusion nadir, analysis of covariance revealed a similar degree of early salvage in the study and control groups (p = 0.3). However, at 6 weeks, the median infarct size for study pts was 0. Using logistic regression analysis, significantly more study pts had no final measureable infarction at 6 weeks than control pts at hospital discharge (p = 0.007). After adjusting for infarct size, location and time to treatment, this difference persisted (p = 0.04). Adjunctive ADO and LDO during angioplasty for AMI may favorably affect late final infarction size. Randomized studies assessing 6 week final infarction size are needed.