Thorac Cardiovasc Surg 2004; 52
DOI: 10.1055/s-2004-816675

Effect of cardiopulmonary bypass, off-pump surgery and beating heart procedure supported by the Impella® elect 100 microaxial blood pump for coronary artery bypass grafting on hemodynamics, left ventricular contractility and regional myocardial perfusion in a porcine model

B Bierbach 1, W Kasper-K�nig 1, T Haist 1, M Meier 2, H Pritzer 2, U Hanenkamp 2, G Horstick 3, O Kempski 2, H Oelert 1
  • 1Klinik und Poliklinik f�r Herz-, Thorax- und Gef��chirurgie, Universit�tsklinik Mainz
  • 2Institut f�r Neurochirurgische Pathophysiologie, Universit�tsklinik Mainz
  • 3II. Medizinische Klinik und Poliklinik, Universit�tsklinik Mainz, Germany

Objectives: Hemodynamics, left ventricular contractility and regional myocardial perfusion following internal mammary artery bypass to left anterior descending coronary artery were investigated in an adult pig model.

Material and Methods: Three surgical techniques were applied: group1 (n=8) standard cardiopulmonary bypass and aortic cross clamping, group2 (n=8) off-pump grafting, group3 (n=8) ImpellaOelect100 assisted circulation during OPCAB grafting and group4 (n=8) served as control. Mean arterial pressure (MAP), cardiac output (CO) and left ventricular pressure's first derivate (LVdp/dt) were recorded. Regional myocardial perfusion (RMP) was assessed in 72 biopsies from both ventricles with 15µm fluorescent microspheres. These variables were analysed 30 minutes before, several times during the procedure and throughout 4 hours of reperfusion.

Results: MAP decreased significantly compared to preoperative values during revascularisation in all groups (p<0,05) and stayed below preoperative values during reperfusion (p<0,05). In group1 norepinephrine was administered to maintain an adequate MAP postoperatively. Only in group2 CO was significantly impaired (p<0,05) but recovered to baseline. LVdp/dt was altered in group2 and 3 (p<0,05), finally reached baseline values. RMP in group1 showed ischemia during crossclamping and reactive hyperemia during early reperfusion in all observed areas. In group2 no disturbance in RMP occured throughout the experiment, whereas in group3 RMP generally decreased most markedly in the left ventricular posterior aspect (p<0,05).

Conclusions: Cardiopulmonary bypass and aortic crossclamping result in hemodynamic impairment, RMP shows ischemia and reactive hyperemia. Off-pump surgery creates hemodynamic depression without adverse effects on RMP. Hemodynamic depression can be reduced by the Impella-pump, however a significant reduction in left ventricular posterior wall perfusion persists.