Objective: Continuous antegrade perfusion (AP) may interfere with surgical precision. Continuous retrograde perfusion (RP), on the other hand, cannot sustain the empty-beating hypertrophied hearts. Therefore, alternate antegrade/retrograde perfusion (A(A/R)P) may be a rational technique to preserve the hypertrophied hearts. This study is to determine whether A(A/R)P could maintain myocardial energy metabolism, oxygenation, and contractile function of the empty-beating hypertrophied hearts.
Methods: Sixteen hypertrophied pig hearts were divided into four groups (n=4 per group). Group I and II underwent an 80-min A(A/R)P (four 10-min APs and four 10-min RPs), followed by a 20-min reperfusion. Group III and IV were subjected to an 80-min AP and 20-min reperfusion and used as a control. Energy metabolism was evaluated in group I and III using magnetic resonance spectroscopy. Myocardial oxygenation (MO) was assessed in group II and IV using near infrared spectroscopic imaging.
Results: During 80-min A(A/R)P, four episodes of RP resulted in a significant decrease in myocardial phosphocreatine (PCr) and MO. The subsequent AP, however, resulted in complete recovery of the parameters. Moreover, myocardial adenosine triphosphate (ATP) remained at a normal level throughout the 80-min A(A/R)P. As expected, hearts in groups III and IV showed normal level of myocardial PCr, ATP, and MO throughout protocol. Finally, hearts in all four groups showed similar contractile function during reperfusion.
Conclusions: A(A/R)P with four 10-min intervals of AP and RP sustained normal myocardial energy metabolism, oxygenation, and contractile function of empty-beating hypertrophied hearts. We conclude that A(A/R)P is an effective technique for preservation of empty-beating hypertrophied hearts during valvular surgery.