Objective: To show the effect of myocardial support by micropumps during beating heart CABG for triple vessel disease.
Methods: In 12 sheep, three coronary arteries (LAD, intermediate branch and circumflex) were consecutively occluded for 10 min. The animals were divided in two groups: group 1 without support (n=6) and group 2 with biventricular support of intravascular micropumps. The pumps (diameter 6.4 mm) were placed through peripheral access (femoral artery and jugular vein) and advanced under fluoroscopic guidance. The hemodynamic evolution was analyzed during the procedure and 2 h of reperfusion. Myocardial flow was assessed by colored microspheres. Differences between groups were analyzed by ANOVA for repeated measurements and post-hoc testing in case of significance.
Results: All of the pump-supported animals survived the procedure, 1 of the control animals died of resistant ventricular fibrillation. At the end of the reperfusion period, the hemodynamic performance and myocardial contractility was significantly better in the pump-supported group (cardiac output: 2.4+/-0.9 vs. 3.3+/-0.9 l/min, P=0.0192; mean arterial blood pressure: 51+/-23 vs. 73+/-9 mmHg, P=0. 036; first derivative of the left ventricular pressure: 561+/-271 vs. 947+/-316 mmHg/s, P=0.0074). After the procedure, subendocardial blood flow was significantly better in all areas of the left ventricle in group 2 (0.935+/-0.427 ml/min per g vs. 0.409+/-0.183 ml/min per g in group 1; P=0.0366).
Conclusion: The supported heart is more resistant to repetitive local ischemia. Support by microaxial pumps can make beating heart surgery safer and applicable for more complex cases.