Effect of Pressure on Myocardial Function After 6-Hour Preservation With Blood Cardioplegia

Abstract Background . This study examined the return of cardiac function in pig hearts after 6 hours' preservation by continuous perfusion with blood cardioplegia at two perfusion pressures compared with preservation with crystalloid solutions. Methods . Isolated pig hearts were randomly divided into five groups (n = 8 per group) according to the following treatments: group 1=fresh hearts (control); group 2=hearts arrested with Queen's cocktail cardioplegia and then immersion in 0°C saline solution (QS group); group 3=hearts arrested with (5°C) and simple immersion in 0°C University of Wisconsin solution (UW group); and groups 4 and 5=hearts arrested with blood cardioplegia at 10°C and then continuously perfused at a pressure of 80 cm H 2 O or 40 cm H 2 O, respectively (groups BC80 and BC40). After preservation for 6 hours, donor hearts were reperfused by a cross-circulation support pig. Thereafter, cardiac function and metabolism were examined every half hour for 2 hours. A three-way mixed general linear model was used to analyze data with repeated measures. Bonferroni test was used to determine differences ( p ≤ 0.05) between groups. Results . Only 4 hearts recovered electric activity in the BC80 group ( p ≤ 0.05 versus other groups). There was poor recovery of left ventricular work in the BC80 group compared with the other groups ( p p p ≤ 0.001). Coronary flow in the QS, UW, and BC40 groups was lower than in the control group ( p p ≤ 0.001). Conclusions . Continuous perfusion with 10°C blood cardioplegia at 40 cm H 2 O pressure for 6 hours provided adequate preservation of systolic function in this model. University of Wisconsin solution provided the best protection of diastolic function.