Morphological methods for evaluation of myocardial protection.

A review is presented of histological, histochemical, and electron microscopical methods considered useful in the morphological evaluation of intraoperative myocardial protection. Transmural samples of myocardium should be studied since the response of the ventricular walls to ischemic injury is not homogeneous. Collection of samples should be continued until the injury reaches a stable end-point. Emphasis is placed on the fact that ischemic injury is modified considerably by reflow phenomena. Ultrastructural studies are indispensable and histological methods are of limited value in the morphological evaluation of early myocardial injury.