THE SAFETY OF SIMULTANEOUS ARTERIAL AND CORONARY SINUS PERFUSION - EXPERIMENTAL BACKGROUND AND INITIAL CLINICAL-RESULTS

Concern over myocardial damage from simultaneous arterial (antegrade) and coronary sinus (retrograde) perfusion has led to alternating betwe en these delivery routes to maximize their individual benefits. Based upon predominant retrograde drainage via Thebesian veins, this study: (1) confirms experimentally the safety of simultaneous arterial and co ronary sinus perfusion; and (2) reports initial clinical application o f this combined strategy in 155 consecutive patients. Experimenal: Fiv e mini-pigs (25 to 30 kg) underwent 1 hour of aortic, clamping with si multaneous aortic and coronary sinus perfusion at 200 mL/min with norm al blood (37 degrees C) before and after 30 minutes of perfusion with either warm (37 degrees C) Or cold (4 degrees C) blood cardioplegia. C oronary sinus pressure was always less than 30 mmHg. There was no righ t or left ventricular edema, lactate production, or lipid peroxidation as transmyocardial and myocardial conjugated dienes were unaltered, a nd postbypass recovered left ventricular end-systolic elastance (condu ctance catheter) and preload recruitable stroke work index 101% +/- 3% and 109% +/- 90%, respectively. Clinical: Simultaneous arterial/coron ary sinus perfusion was used in 155 consecutive high risk patients (Ne w York Heart Association Class III to IV) undergoing isolated coronary . artery bypass grafting (CABG) (n = 109) and CABG + valve replacement /repair or aneurysm (n = 46). Included were 16 patients in cardiogenic shock and 24 undergoing reoperation. Mean aortic clamping time averag ed 90 +/- 4 minutes (range 30 to 207), with 3.5 +/- 0.1 grafts per pat ient; all anastomoses were performed with the aorta clamped. Cold inte rmittent blood cardioplegia was used for distal anastomoses and valve implantation/repair in 123 patients, and warm continuous blood cardiop legia was used in 32 patients. Following a warm cardioplegic reperfusa te, all patients received warm noncardioplegic blood perfusion 'simult aneously via grafts and coronary sinus. Coronary sinus pressure was al ways less than 40 mmHg. Of 18 patients requiring postoperative mechani cal circulatory support (IABP), 16 had IABP placed preoperatively for cardiogenic shock. There were three postoperative myocardial infarctio ns (2%), and six patients died (3:9% mortality). Conclusion: These exp erimental and clinical findings overcome perceived concerns about myoc ardial damage from simultaneous arterial and coronary sinus perfusion, and suggest this approach may add to the armamentarium of cardioprote ctive strategies.