Pulmonary and coronary endothelial effects of acute myocardial ischemia in dogs

Abstract

We measured pulmonary arterial (Ppa) and left atrial (Pla) pressures, lung lymph flow rate (QL), and protein clearance in 23 anesthetized dogs with ligation (MI) dogs or sham ligation (sham-MI dogs) of a coronary artery combined with either large transient increases in Pla or moderate steady-state increases in Pla. In steady-state experiments we also collected cardiac lymph. Plasma and lymph concentrations of several prostanoids including prostacyclin (PGI2) and thromboxane B2 (TXB2) were measured. Lung lymph flow rates and protein clearances were increased in MI dogs compared with those in sham-MI dogs in experiments with transient increases in Pla. Similarly in steady-state experiments lung QL and protein clearance were increased after MI. Cardiac QL increased after MI with no change in lymph protein clearance. Lung and cardiac lymph PGI2 and plasma TXB2 concentrations increased after MI. We suggest that acute MI results in increased lung vascular permeability and that activation of formed elements in blood may be involved in mediating MI-induced vascular injury.