Myocardial Protection in Valve Replacement Procedures: Moderate Systemic Hypothermia versus Cold Cardioplegic Arrest - A 4 1/2 Years' Experience

Summary

To evaluate the efficacy of 2 methods of myocardial protection, hospital mortality and major complications in the early postoperative period were analyzed retrospectively among 286 patients who had undergone aortic valve replacement (AVR = 144), mitral valve replacement (MVR = 116), and double valve replacement (DVR = 26) at our institution between January, 1978 and July, 1982. One hundred eight patients were managed by moderate systemic hypothermia during aortic cross-clamping (AVR, DVR) or periods of ventricular fibrillation (MVR). In another 178 patients cold cardioplegic arrest, introduced in January 1980, was used. Both groups showed similar distribution of age, sex and valvular disease. In the cardioplegia group pure stenosis mainly of the aortic valve was more frequent, the number of patients presenting in class III and IV of the NYHA had increased slightly; out of 15 concomitant procedures 3 patients required composite graft replacement of the ascending aorta and 7 aorto-coronary bypass grafts. A larger percentage of the patients of the cardioplegia group (14.6% versus 12% of the hypothermia group) had aortic cross-clamping times of more than 60 minutes ranging from 61 to 103 minutes (cardioplegia) and 61 to 79 minutes (hypothermia).

Cardiac and non-cardiac complications and hospital mortality decreased over the years. The incidence of low output syndrome in the cardioplegia group was 11.8% versus 15.7% in the hypothermia group. Dysrhythmias decreased from 45.3% (hypothermia group) to 34.8% (cardioplegia group). Hospital mortality caused by cardiac and non-cardiac complications fell from 6.5% to 2.8%. The best results (1.03%) were achieved in AVR patients treated with cardioplegic conditions. In DVR procedures hospital mortality was reduced from 9% to 6.6%. Pneumonia (1), coronary artery embolism (3) and severe tricuspid valve incompetence (1) contributed to the 5 deaths occurring in the cardioplegia group of 178 patients.

Key words

Valve replacement procedure - Fatal and nonfatal complications - Myocardial protection - Hypothermia - Cold cardioplegic arrest