Aortocoronary bypass grafting: a comparison of HTK cardioplegia vs. intermittent aortic cross-clamping

Objective: Intermittend, hypothermic aortic cross-clamping (IAC) with myoca rdial fibrillation and cardioplegic arrest (CA) have been established both as effective methods fur coronary artery bypass surgery (CABG). Nevertheles s, there exists controversy about the more beneficial cardioprotective effe ct of one of these procedures in CABG-patients. Methods: In this prospectiv e study we compared the clinical outcome, ischemic serum-markers (CK, CK-MB , Troponin I), electrocardiogram (ECG)-changes, and hemodynamic data of 103 patients. Randomization in group I (IAC; n = 52) or group TT (CA; n = 51) was done consecutively, all data were compared by Student's t-test or chi ( 2)-test and P < 0.05 was regarded as significant. The Bretschneider-HTK sol ution was used for cardioplegic arrest. Data were collected before operatio n, before ischemic arrest, after 5 and 60 min of reperfusion, 1 and 6 h aft er operation, 1, 2 and 10 days postoperatively. Results: There were no sign ificant differences between both groups regarding general patient data: age (LAC: 64.8 +/- 9.2 vs. CA: 63.8 +/- 9.0 years), left ventricular function (ejection fraction: IAC: 61 +/- 14 va CA: 64 +/- 13%), the amount of bypass ed Vessels (IAC: 3.4 +/- 0.5 vs. CA: 3.6 +/- 0.5), total bypass time (IAC: 113 +/- 31 vs. CA 108 +/- 20 min). The total time of ischemia was significa ntly less in the IAC group with 37 +/- 10 vs. 48 +/- 10 min in the CA group . In the IAC-group, a higher mortality was noticed (7.7 vs. 3.9%; N.S.). Th is was combined with a significantly higher amount of patients with peak se rum-values of CK-MB (>40 U/l) and troponin I (>50 ng/ml), 17 in the IAC-gro up (33%) vs. eight in CA-group (16%). Cerebral strokes were seen in two IAC -patients and none in CA-patients (NS). EGG-changes occurred in 22 IAC pati ents (42%) vs. 16 CA patients (31%); persistent ischemia related EGG-change s in six IAC (11.5%) vs, five CA-patients (9.8%). Conclusions: Both cardiop rotective methods, IAC and HTK-cardioplegia, seem to offer sufficient myoca rdial protection in normal CABG-procedures. Although nt urologic disorders and mortality rates were higher in patients with intermittent aortic cross- clamping, the differences to the cardioplegia group were not significant. A ccording to the analysis of increased EGG-changes, higher CK-MB and troponi n I values, which occurred especially in patients with myocardial ischemia time longer than 40 min, we conclude that cardioplegic arrest with HTK seem s to offer more beneficial effects in procedures with prolonged ischemia. ( C) 2000 Elsevier Science B.V. All rights reserved.