The Study Of The Myocardial Protection Effect Of Antegrade Tepid And Cold Blood Cardioplegia In MVR Or/and AVR

Objective: Cold intermittent antegrade cardioplegia has been the benchmark for myocardial protection. Intermittent tepid blood cardioplegia has been reported as a valuable alternative for myocardial protection in cardiac surgery, however, conflicting experimental data have been published. Most of the advantages of blood cardioplegia are temperature dependent: which occur at 37℃ and are probably less effective when the temperature is lowered, on the other hand, myocardial requirements increase as the temperature rises, therefore, the question arise as to what is the best compromise. The purpose of this study is to assess the effectiveness of intermittent tepid cardioplegia in mitral valve replacement (MVR) or/and aortic valve replacement (AVR).Methods: From Aug. 2003 to Dec. 2004, 60 consecutive patients, comprising 29 men and 31 women, were included in this study. Therewere no significant difference in age, gender, weight, heart function class, C/T ratio, LVDs, LVDd, ejection fraction between two groups. We measured the release of cardiac troponin-I (cTn-I), a highly sensitive and specific marker of myocardial damage, and creatine kinase MB isoenzyme (CK-MB), in 30 patients who underwent MVR or /and AVR with antegrade intermittent tepid blood cardioplegia (26 ℃), in comparision with 30 patients who underwent MVR or/and AVR with antegrade intermittent cold blood cardioplegia (6℃), being the cold group. Blood samples were taken to determine the serum concentrations of cTn-I and CK-MB before and after anesthesia, then 6h and 16h after the termination of cardiopulmonary bypass (CPB), meantime clinical data including duration of CPB, aortic cross clamping time, duration of ventilator support, intensive care unit stay, spontaneous beating, electrical defibrillation, dosage of dopamine hydrochloride in first 24 hours post operation.Results: The levels of cTn-I and CK-MB before and after anesthesia are no significant difference between two groups. The serum cTn-I and CK-MB after CPB was significantly lower in the tepid group than in the cold group. The rate of spontaneous beat after declamping in tepid group is higher than in cold group. The maximum dose of dopamine during the first 24 hours post operation is lower in tepid group than in cold group.Conclusion: Intermittent antegrade tepid blood cardioplegia is appropriate and clinically safe .Intermittent antegrade tepid blood cardioplegia show effective myocardial protection in MVR or /and AVR than intermittent antegrade cold blood cardioplegia. Intermittent antegrade tepid blood cardioplegia is an alterative of intermittent antegrade cold blood cardioplegia.