REDUCED PULMONARY MICROVASCULAR PERMEABILITY IN SEVERE CHRONIC LEFT HEART-FAILURE

Pulmonary edema is a serious complication of heart failure, but often patients with chronic heart failure resist pulmonary edeme despite elevated pulmonary venous pressures. This protection might be a result of decreased pulmonary microvascular permeability. Double-isotope scintigraphy with indium-113m-labeled transferrin and technetium-99m-labeled erythrocytes allows noninvasive estimation of pulmonary microvascular permeability; an index of transferrin accumulation is calculated that reflects microvascular permeability. Fourteen patients with severe chronic left ventricular dysfunction were compared with a control group of 15 patients with mild coronary artery disease. In the control group the transferrin accumulation index was 0.35 (range -0.3 to 1.0) X10(-3)/min, and in patients with heart failure the index was 0.0 (range -1.0 to 0.7) X10(-3)/min, which was significantly lower (p < 0.01). The reduction in the transferrin accumulation index correlated weakly with the duration of heart failure (R = -0.5, p < 0.02). These data indicate reduced protein efflux consistent with a decrease in pulmonary microvascular permeability in patients with severe chronic heart failure. Similar changes have been observed in severe mitral stenosis and may reflect a generalized adaptation to chronic pulmonary venous hypertension.