Correlation of patterns of subendocardial reperfusion and left ventricular performance after ischemia.

Ninety-three dogs were studied with normothermic or hypothermic ischemia for 60 or 90 minutes, with or without potassium cardioplegia. Radioactive-labeled microspheres (9 +/- 1) were injected into the aortic perfusion cannula just prior to aortic cross-clamping and at 2, 6, and 10 minutes after the clamp was released. Left ventricular (LV) function was analyzed with a right heart bypass model before and 45 minutes after the ischemia period. Changes in LV function were defined as the arithmetic difference in the center of mass between preischemia and postischemia computer-drawn Sarnoff curves. Regardless of technique of myocardial protection, increased subendocardial flow 2 minutes after ischemia correlated strongly with preservation of LV function (p less than 0.01). Well-preserved hearts showed a rapid return to normal levels of coronary blood flow (p less than 0.01). In contrast, a delay in the peaking of subendocardial flow to 10 minutes was associated with poor function (p less than 0.01). There was a high correlation between ultrastructural morphology and LV function. While well-preserved hearts showed early preferential subendocardial perfusion, the poorly protected myocardium is unable to restore adequate subendocardial flow early in the reperfusion period.

Tricuspid valve replacement for cardiogenic shock after acute right ventricular infarction.

A 66-year-old man had an acute inferior wall myocardial infarction complicated by hypotension, high-grade atrioventricular block, and distended neck veins, suggesting associated right ventricular infarction. He failed to respond to volume loading, intra-aortic balloon counterpulsation, and pharmacologic afterload reduction. Cardiac catheterization five days after the infarction disclosed severe tricuspid regurgitation and a hemodynamic pattern resembling pericardial constriction. Emergency tricuspid valve replacement was dramatically successful.

Nutritional support in cardiac cachexia.

A nutritional survey of 350 hospital patients reveals 50 with cardiac disease who had clinically significant protein-calorie malnutrition. Assessment criteria of malnutrition (per cent normal) included triceps skin fold (52 per cent), arm muscle circumference (88 per cent), and impaired delayed hypersensitivity skin testing (i.e., deficiency in cell-mediated immunity), the latter frequently observed in patients with concurrent weight loss. The functional category of cardiac status was not precise in predictin the morbidity and mortality of 14 patients undergoing cardiac valvuloplasty. By contrast, a nutritional/metabolic profile using weight loss, triceps skin fold (35 per cent), arm muscle circumference (27 per cent), and cell-mediated immunity (29 per cent) did identify high-risk patients who could be expected to benefit by concurrent nutritional support (4/4). Further studies are indicated to determine if nutritional support for cardiac cachexia can reduce the levels of morbidity and mortality during mitral and tricuspid valve surgery.

Extracorporeal perfusion for acute respiratory failure: recent experience with the spiral coil membrane lung.

Selection criteria, clinical data, and physiological measurements obtained during five extracorporeal membrane lung perfusions for acute respiratory insufficiency are presented. Four patients died and 1 survived. A new technique of femoral artery cannulation to allow aortic arch perfusion is described. When properly monitored, this route provides improved oxygen delivery to the brain during venoarterial (VA) perfusion. The importance of monitoring the equivalent of carotid artery Po2 during VA perfusion is emphasized. Recognition of the effects of high cardiac output in limiting the quality of extracorporeal perfusion, plus the use of hypothermia to reduce output, are stressed. We have confirmed that perfusion can be accomplished with small quantities of heparin, so that bleeding is reduced, but thrombocytopenia and occasional hemorrhage continue to be persistent problems.