Coronary Flow Supplementation in Experimental Myocardial Infarction with Shock

¹ Division of Artificial Organs, Department of Surgery and Institute for Biomedical Engineering, University of Utah, Salt Lake City

Cardiogenic shock was induced in 12 anesthetized sheep by ligating branches of the left coronary artery. Coronary blood flow (CBF) did not decrease until shock was produced by the serial coronary artery branch ligations. Perfusion of the left coronary artery with arterial blood was performed using a special nonocclusive catheter. Perfusion flow rate (PFR) increments up to an optimal level resulted in improvement of left ventricular (LV) function as expressed by rise in cardiac output, fall in left atrial pressure and increase of systemic blood pressure up to a level approximating the control. Higher PFR resulted in deterioration of these variables. The improvement of LV function was related to the increased CBF. It is concluded that in experimental myocardial infarction with shock, supplementation of the CBF deficit, which resulted from decreased systemic blood pressure and increased CBF requirements, can improve the LV function up to the preligation levels. Beyond an optimal perfusion flow rate, autoregulatory phenomena result in decreased CBF and decline of LV function.