PROSPECTIVE RANDOMIZED TRIAL OF SINGLE CLAMP TECHNIQUE VERSUS INTERMITTENT ISCHEMIC ARREST - MYOCARDIAL AND NEUROLOGICAL OUTCOME

Objective: To explore the hypothesis that intermittent ischaemic arres t (IIA) provides better myocardial preservation but generates a larger number of cerebral microemboli (ME) and consequently a higher inciden ce of post-operative cerebral dysfunction compared with the single cla mp technique (SCT). Methods: Ninety-one patients with stable angina un dergoing elective CABG with no clinical evidence of aortic or cerebro- vascular or neurological disease were prospectively randomized to: IIA (n = 43) or SCT with intermittent anterograde cold blood cardioplegia (n = 48). Myocardial preservation was assessed by measuring serum CK- MB, Troponin-T (TnT) and Troponin-I (TnI) and from pre- and post-opera tive ECGs and left ventricular (LV) function by echocardiography. Intr a-operative cerebral ME were counted by transcranial Doppler of the ri ght middle cerebral artery. All patients completed the Luria Nebraska Neuropsychological Battery (LNNB) tests for motor, visual, reading, me mory and intellectual processes the day before surgery and at 1 week a nd 6 months postoperatively. Serum levels of the neuro-specific protei n S-100 were measured. Results: The two groups were comparable for age , sex, extent of coronary disease, previous myocardial infarction, dia betes, hypertension and number of arterial and venous grafts. The medi an number of ME detected per patient was 34 (range 4-208) and was simi lar in both groups. Protein S-100 levels remained normal and similar i n both groups at all times except in one patient with SCT who had an o perative stroke. LNNB scores were similarly depressed at 1 week and re covered in all cases at 6 months. There was no correlation between the number of ME and LNNB scores. Median peak TnI levels were 0.64 mu g/l with IIA vs. 0.87 mu g/l with SCT (P = NS) and TnT 0.8 mu g/l vs. 1.0 8 mu g/l (P < 0.03). SCT was however associated with longer mean ischa emic (67.6 +/- 16.1 vs. 34.5 +/- 16.5 min, P < 0.001) and mean bypass time (88.5 +/- 18.2 vs. 74.6 +/- 26.3min, P < 0.004) than IIA, Four pa tients with SCT and none with IIA had ECG changes suggestive of MI (P = 0.04). Conclusion: During elective CABG in patients with no clinical evidence of aortic or cerebro-vascular disease the incidence of peri- operative ME and post-operative neuropsychological disturbances are co mparable with both techniques of myocardial preservation. Biochemical analysis suggests that IIA provides more effective myocardial preserva tion. (C) 1998 Elsevier Science B.V. All rights reserved.