Lesions of myocardial capillary vessels during open-heart surgery.

In a clinical series of patients undergoing open-heart surgery, capillary lesions in the myocardium were common when hypothermic chemical cardioplegia was used for myocardial protection during aortic cross-clamping. It seems obvious that the resulting oedematous swelling of the capillary wall, especially that of the endothelial cells, may constitute an anatomic intraluminal obstacle to myocardial reperfusion, thereby further delaying the recovery. After (mere) topical cooling, only minor capillary changes were observed. In contrast to the oedematous transformation described above for the former group, capillary endothelial cells and pericytes of the latter were diminished in cellular volume.