MYOCARDIAL PROTECTION BY PRESSURE-CONTROLLED AND VOLUME-CONTROLLED CONTINUOUS HYPOTHERMIC CORONARY PERFUSION (PVC-CONTHY-CAP) IN COMBINATION WITH ULTRA-SHORT BETA-BLOCKADE AND NITROGLYCERINE

The aim of the study was to validate clinically a new technique of myo cardial protection developed for intra- and extracardiac surgery on th e beating heart. The concept combines the principle of continuous pres sure- and volume-controlled coronary artery perfusion (PVC - CONTHY - CAP) with the specific myocardioprotective effects of hypothermia and nitrates and, on the other hand, with the beta-blocker-mediated reduct ion of chronotropy and inotropy necessary for convenient surgery. Unde r standard ECC conditions after cross-clamping the aorta coronary perf usion with oxygenated blood enriched with nitroglycerine (10 mu g/kg/h ) and esmolol (0.05 mg/ml flow/min) is started via an additional perfu sion cannula placed in the aortic root. The temperature of the perfusa te is maintained at 32 degrees C, the intraaortic pressure at 40-70 mm Hg and the perfusion flow in the range 0.8-1.0 ml/g heart muscle/min. In CABG procedures an additional perfusion catheter is used for perfus ion of distal coronary artery segments. Using this technique 100 conse cutive patients, adults and children, were operated on between 2/96 an d 8/96. In 84 adult patients (age: 45-82yrs), 78 CABG procedures (54 e lective, 13 urgent, 11 acute) with a mean bypass count of 3.7 (range 1 -7), 69 ITA grafts, 72 grafts to CX, and 3 MVRec/MVRpl, and 6 pure MVR ec/MVRpl procedures (1 urgent, 1 emergency) were performed. The mean c oronary perfusion time was 48 min (range 21-88 min). In 5 patients per ioperative infarction (CABG; 1 emergency after PTCA, 4 elective) with significant increase of CK-MB values (57-98 U/L) occurred. In the 4 el ective patients (3 with diabetes mellitus) re-intervention was not pos sible due to small-vessel disease. In one patient with preoperative in farction IABP was necessary. No patient died. There were 16 children ( age: 4weeks-16yrs): VSD, n=6, AV-C, n=2, TOF, n=1, MVRec, n=1, DORV (R astelli), n=2, SV (TCPC), n=3, and PV obstruction, n=1. The mean coron ary perfusion time was 97 min (range: 27-260 min). The mean ICU stay 3 .9 d (range: 1-10d). One child died (TCPC) on the 10th postoperative d ay due to multi-organ failure. In conclusion, PVC-CONTHY-CAP is design ed especially for emergency and urgent procedures, i.e. patients with PTCA-related complications, patients with severely depressed LV functi on, and patients with complex congenital cyanotic heart defects. Using PVC-CONTHY-CAP, coronary artery bypass grafting as well as intracardi ac procedures for congenital and acquired heart defects can be perform ed safely and conveniently, the system is easy to handle for both the cardiac surgeon and perfusionist. Due to its pharmacological propertie s continuous intracoronary application of nitrates in combination with hypothermia seems to be essential as a preventive treatment modality for the ischemic state.