Efficacy and adverse effects of the coronary active perfusion system--from a viewpoint of perfusional timing

We developed a coronary active perfusion system (CAPS) to avoid myocardial ischemia during off-pump coronary artery bypass (OPCAB). The purpose of this study was to determine the optimal timing of CAPS perfusion, and to investigate any adverse effects when it is driven within the systolic phase. Twenty-four pigs were divided into four groups: (A) systolic, (B) early-diastolic, (C) middle-diastolic, and (D) late-diastolic perfusion. Myocardial blood flow (MBF), hemodynamic and mechanical data were measured during 30 minutes of CAPS perfusion. MBF in group A was lower than in the other groups (p<0.001), but no significant differences were observed among groups B to D. End-systolic pressure-volume relation (Mw) and preload recruitable stroke work relation (Ees) in group A was lower than in groups B to D (p<0.01 and p<0.05, respectively), but no significant differences were observed among groups B to D. CAPS could maintain regional MBF and left ventricular function if it was driven only within the diastolic phase and required no strict adjustment, but CAPS has an adverse effect when it is driven in the systolic phase.