Myocardial protection during surgical ventricular restoration

Abstract

Objective: Ventricular restoration is a novel procedure for treating congestive heart failure (CHF). The two important features include a technically correct procedure and adequate myocardial protection. The two protective techniques include conventional cardioplegia and the beating heart.

Methods: This report reviews a RESTORE clinical registry and summarizes background experimental work related to myocardial protection in failing dilated hearts.

Results: The RESTORE registry is reported, where protection is 55% with cardioplegia and 45% with beating heart. The beating method was used more frequently in patients with ejection fraction <30%, end systolic volume 80 ml/m2, NYHA class >III/IV. Overall survival results favored cardioplegia except for the first 30 days, but after matching patients on age, ejection fraction (EF) and NYHA the beating results and cardioplegic results were comparable. Experimental work evaluated the safety of the beating method in failing dilated ventricles under acute conditions. Supplemental coronary perfusion studies in chronically dilated hearts after tachycardia induced cardiomyopathy were analyzed to show that (a) there was vascular remodeling (less flow at the same pressure in failing hearts with cardioplegic, but not beating delivery; (b) in the open state (used during restoration) subendocardial flow increased in the beating heart, and fell after cardioplegia. These studies were done without ischemia.

Conclusions: Cardioplegic delivery for protection is 'time dependent' (needing ischemic intervals) while beating nourishment is 'procedure dependent,' as continuous perfusion is provided throughout the procedure is suggested. The importance of maintaining high perfusion pressure is emphasized.