Background: Cardiopulmonary bypass (CPB) time and aortic cross-clamp time are critical intraoperative
factors influencing mortality in cardiac surgery. However, their relative importance
may differ across patient risk categories. This study compares the predictive value
of CPB time and cross-clamp time in low-risk (EuroSCORE II < 8) and high-risk (EuroSCORE
II ≥ 8) patient groups undergoing elective cardiac surgery.
Methods: We analyzed data of 12,395 patients, who underwent elective cardiac surgery in our
clinic from 2004 to 2024. We performed univariate logistic regression analyses to
assess the impact of CPB time and cross-clamp time on 30-day mortality in both low-risk
and high-risk patients. Separate models were constructed for each variable, with mortality
as the dependent outcome. Predictive strength was evaluated using pseudo R-squared
values and regression coefficients.
Results: For low-risk patients, the odds of mortality increased by 1.48% per minute of CPB
time (OR = 1.0148, p < 0.001), while cross-clamp time increased mortality odds similarly by 1.48% per
minute (OR = 1.0148, p < 0.001). The pseudo R-squared values were higher for CPB time (0.0875) compared
with cross-clamp time (0.051), indicating that CPB time had a stronger impact. In
high-risk patients, the odds of mortality rose by 1.02% per minute of CPB time (OR = 1.0122,
p < 0.001), compared with 1.10% for cross-clamp time (OR = 1.0110, p < 0.001). CPB time also had a higher predictive value (pseudo R-squared = 0.077)
than cross-clamp time (pseudo R-squared = 0.053) in this group.
Conclusion: CPB time is a stronger predictor of mortality than aortic cross-clamp time in both
low- and high-risk patients. However, the impact of both factors on mortality is reduced
in high-risk patients, suggesting that other factors, likely related to preoperative
condition and comorbidities, contribute more significantly to mortality in this group.
These findings highlight the complexity of predicting outcomes in high-risk patients
and suggest a need for further investigation into additional risk factors.