GINKGO-BILOBA EXTRACT (EGB-761) PRETREATMENT LIMITS FREE RADICAL-INDUCED OXIDATIVE STRESS IN PATIENTS UNDERGOING CORONARY-BYPASS SURGERY

A growing body of evidence supports the trigger role of free radicals in the delayed functional and metabolic myocardial recovery following cardiopulmonary bypass (CPB) in humans, thus opening the field to spec ific therapies. This clinical study was designed to evaluate, in 15 pa tients undergoing aortic valve replacement, whether the extent of CPB- and reperfusion-induced Lipid peroxidation, ascorbate depletion, tiss ue necrosis, and cardiac dysfunction is reduced by orally administered EGb 761, a Ginkgo biloba extract with potent in vitro antiradical pro perties. Patients received either EGb 761 (Tanakan, 320 mg/day, n = 8) or a matching placebo (n = 7) for 5 days before surgical intervention . Plasma samples were obtained from the peripheral circulation and the coronary sinus at crucial stages of the operation (i.e., before incis ion, during ischemia, and within the first 30 minutes post-unclamping) , and up to 8 days postoperatively. Upon aortic unclamping, EGb 761 in hibited the transcardiac release of thiobarbituric acid-reactive speci es (p < 0.05), as assessed by high-performance liquid chromatography, and attenuated the early (5-10 minute) decrease in dimethylsulfoxide/a scorbyl free radical levels, an electron spin resonance index of the p lasma ascorbate pool (p < 0.05). EGb 761 also significantly reduced th e more delayed leakage of myoglobin (p = 0.007) and had an almost sign ificant effect on ventricular myosin leakage (p = 0.053, 6 days postop eratively). The clinical outcome of recovery of treated patients was i mproved, but not significantly, compared with untreated patients. Our results demonstrate the usefulness of adjuvant EGb 761 therapy in limi ting oxidative stress in cardiovascular surgery and suggest the possib le role of highly bioavailable terpene constituents of the drug.