Effects of an Abdominal Left Ventricular Assist Device on Myocardial Oxygen Supply/Demand Ratios in Normally Perfused and Ischemic Bovine Myocardium

The effects of an abdominal left ventricular assist device (ALVAD) on subendocardial oxygen supply/demand ratios as reflected by diastolic pressure-time index/tension-time index (DPTI/TTI) were investigated in calves. Control DPTI/TTI ratios were 1.09 ± 0.12 (mean ± SD). With ALVAD actuation the ratios increased to 5.73 ± 3.2. Following circumflex coronary artery occlusion, control ratios decreased to 0.04 ± 0.05 in the ischemic area and 0.97 ± 0.20 in the nonischemic areas. With ALVAD actuation in the presence of circumflex occlusion, the depressed ratios were increased to 1.37 ± 0.39 in the ischemic zone and 9.71 ± 2.5 in the nonoccluded segments. Subendocardial oxygen supply/demand ratios were significantly improved by ALVAD assistance following induced subendocardial ischemia.