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The purpose of these studies was to characterize the rates of fatty acid oxidation in reperfused myocardium and test the influence of excess fatty acids (FA) on mechanical function in the extracorporeally perfused, working swine heart model. Seventeen animals were prepared. Eight were untreated (LOW FA group; serum FA averaged 0.55 +/- 0.07 mumol/ml) and nine received a constant infusion of 10% Intralipid with heparin to raise serum FA to about 1.4 +/- 0.21 mumol/ml (HIGH FA group). Coronary flow in both groups was held at aerobic levels for an equilibrium period of 40 minutes, acutely reduced regionally in the anterior descending circulation by 60% for 45 minutes, and acutely restored to aerobic levels for 60-minute reflow. Appreciable mechanical depression (-47 delta% from aerobic values; p less than 0.01) during reperfusion was noted in both groups. This was associated with modest reductions in myocardial oxygen consumption (p less than 0.05) and losses of total tissue carnitine stores (p at least less than 0.02). Reperfused myocardium showed a strong preference for and aerobic use of FA during reflow such that 14CO2 production from labeled palmitate exceeded preischemic levels (+89 delta% in LOW FA hearts; +111 delta% in HIGH FA hearts). This suggested relative preservation of restoration of certain elements in mitochondrial function during reflow. The findings argue for uncoupling between substrate metabolism and energy production, accelerated but useless energy drainage, or some impairment between energy transfer and function of contractile proteins as possible explanations for the persistent depression of mechanical function (stunning) during reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

To compare angiographically-determined coronary artery disease in diabetic patients with controls, 1,653 patients coming to cardiac catheterization were reviewed retrospectively to find 37 diabetic and 79 control patients matched for sex, age (+/- 3 years), and risk factors (hypertension, hyperlipidemia, and smoking). The severity of coronary artery disease was assessed using an angiographic grading system. The following results were obtained: 16 of 37 diabetic patients (43%) had three-vessel disease compared to 20 of 79 controls (25%). Seventy-six of 111 (68%) diabetic vessels were diseased compared to 110 of 237 control vessels (46%) (P less than 0.005). The total coronary score reflecting total extent of disease for diabetic patients was 371 (mean 10.0 +/- (SEM) compared to 594 for controls (mean 7.5 +/- 0.7, (P less than 0.01). Diabetic patients had a statistically similar number of diffusely diseased vessels as controls (28% vs 22%). There were only three of 76 diabetic vessels (4%) considered inoperable compared to seven of 110 (6%) control vessels. We conclude that diabetic patients with chest pain have more coronary artery disease than nondiabetics, but no more diffuse or inoperable disease.

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Fatty acids in excess impair mechanical function and electrical stability in ischemic hearts. The purpose of the present studies was to test whether oxfenicine, an agent capable of reducing fatty acid metabolism, can prevent these consequences and in so doing improve hemodynamic performance. Two groups of working swine hearts (n = 15), extracorporeally perfused with whole blood, were compared over 90 min of controlled coronary perfusion. An emulsion of triacylglycerols (Intralipid) with heparin were administered systemically to augment serum fatty acids threefold (0.30 to 0.92 mumol/ml). Labeled [U14C]palmitate was administered selectively into the left anterior descending coronary circulation to follow fatty acid oxidation. Coronary flow in this bed was decreased by 50% over the final 30 min of perfusion. Saline (n = 7) or oxfenicine (17-33 mg/kg, n = 8) was administered to placebo or treated animals at 30 min perfusion. 14CO2 production from labeled palmitate was decreased by 55% (P less than 0.025) at normal flows in oxfenicine-treated hearts and was reduced further during ischemia. Tissue levels of acyl carnitine were significantly reduced and acetyl CoA levels significantly increased in oxfenicine-treated hearts both in aerobic and ischemic myocardium. These changes were associated with an improvement in mechanical function. Left ventricular systolic and developed pressures and maximum left ventricular dP/dt were increased by 36 delta %, P less than 0.01; 46 delta %, P less than 0.025; and 41 delta %, P less than 0.025, respectively, at end ischemia as compared with placebo hearts.(ABSTRACT TRUNCATED AT 250 WORDS)