Blood cardioplegia benefits only patients with a long cross-clamp time

A clear advantage of blood versus crystalloid cardioplegia has not yet been observed in smaller population studies. The purpose of this article was to further investigate the clinical outcomes of blood versus crystalloid cardioplegia in a large propensity-matched cohort of patients who underwent cardiac surgery.

The study was a single-centre study. Data was withdrawn from the Western Denmark Heart Registry, which comprises a perfusion section for each procedure. A total of 4,852 patients were propensity matched into crystalloid (CC) vs blood cardioplegia (BC) groups. The primary end points were creatinine kinase-MB (CKMB) elevation, acute myocardial infarction (AMI), stroke, dialysis, coronary angiography (CAG) and mortality (30 days and 6 months).

We found lower odds ratio in 30-day mortality in the BC group (OR 0.21; CI 0.06-0.68), but no difference in overall 6-month mortality. There was no difference in CKMB elevation, AMI, dialysis or stroke. Several end points were further analysed for different cross-clamp times. In the CC group, ventilation time above 600 minutes was seen more often in almost all cross-clamp time intervals (23.5 % vs 12.2 %; p<0.0001; χ²-test) and 6-month mortality was significantly higher when the cross-clamp time exceeded 210 minutes (64.3 vs 23.8; p=0.018; χ²-test).

We did not find clear evidence of superiority of either type in the uncomplicated patient. When prolonged cross-clamp time or postoperative ventilation is expected, this study indicates that blood cardioplegia might be preferable.