MYOCARDIAL DAMAGEq

Abstract

Background: Intermittent antegrade warm blood cardioplegia is routinely usedas a mean of myocardial protection since its introduction. There is a considerable debate onthe longest time off cardioplegia interval during aortic cross clamping. Objective: To see thefrequency and extent of myocardial damage in patients undergoing CABG receiving intermittentantegrade warm blood Cardioplegia at LTOC (longest time off cardioplegia) 11-15 minutes(Group I) and 16-20 minutes (Group II). Patients and Methods: A randomized prospectivestudy involving 94 patients was arranged to see the safe periods of intermittency. There weretwo groups of patients having LTOC of 11-15 minutes (Group I) and 16-20 minutes (GroupII). 20 minutes was the upper limit. The duration of study was from 1-09-2013 to 10-02-2014.Data was analyzed using SPSS Version 16. Independent sample t-test and chi-square wereapplied to see the significance. Results: Mean age was 54.1±9.36 years. There were moremales as compared to females. More than 50% of the patients had Hypertension and Diabetes.There was no urgent surgery. Triple vessel disease (TVD) was present in 48.9% patients and40.4% had Double vessel disease (DVD). Average blood flow during CPB was 2.4±0.14 (L/min.m-2). Average body temperatures were 31.7±2.30C. Cardioplegia temperature was 36-370C.According to Left Ventricular Function Classification, 43.6% of the patients were of LV grade IIand 10.6% of LV grade III. There was no significant increase in the levels of CK-MB in two groups.77.8% patient in Group I and 66.7% in Group II gained spontaneous rhythm (p-value 0.16). IABPwas inserted in 5.4% patients in group I and 5.6% in group II (p-value 0.97). There was no failureto wean off from bypass and no peri-operative mortality. The levels of inotropes viz dopamineand epinephrine on weaning were also almost the same. Perioperative MI occurred only in 7patients (ruled out by biochemical evidence). Conclusions: A reasonable margin of safetyexists with intermittent antegrade warm blood cardioplegia in these two groups. So the LTOC(longest time off cardioplegia) up to 20 minutes is unlikely to lead to adverse clinical outcomesand is clinically acceptable.