Association Between Post-Cardiopulmonary Bypass Hemodynamics and 30-Day Mortality After Aortic Surgery: A Single-Center, Retrospective Study

Abstract

Background: We evaluated phase-specific associations between perioperative hemodynamic variables and 30-day mortality following aortic surgery requiring cardiopulmonary bypass (CPB) and to assess the utility of post-CPB variables in risk stratification. Methods: We analyzed 691 patients who underwent aortic surgery requiring CPB. Hemodynamic variables were assessed during the preoperative, pre-incision, pre-CPB, and post-CPB phases and included heart rate (HR), systolic blood pressure (SBP), mean blood pressure (MBP), diastolic blood pressure (DBP), shock index (SI; HR/SBP), and modified shock index (MSI; HR/MBP). The primary outcome was 30-day mortality. Holm correction was applied to the between-group comparisons of hemodynamic variables. Adjusted Cox models used ridge penalization and included surgery group, CPB time, and mean post-CPB vasoactive-inotropic score. Results: Thirty patients (4.3%) died within 30 days. After Holm correction, significant differences between survivors and non-survivors remained only for post-CPB SBP, MBP, SI, and MSI. In adjusted Cox models, 30-day mortality was associated with higher post-CPB SI (hazard ratio [95% CI], 1.38 [1.17 to 1.64] per 0.1-unit increase; p < 0.001) and MSI (1.29 [1.12 to 1.47] per 0.1-unit increase; p < 0.001), as well as lower SBP (1.60 [1.24 to 2.05] per 10-mmHg decrease; p < 0.001) and MBP (2.00 [1.32 to 3.03] per 10-mmHg decrease; p = 0.001); in contrast, HR and DBP did not show a significant association with 30-day mortality. Kaplan–Meier analyses confirmed poorer survival across ROC-derived post-CPB thresholds for HR, SBP, MBP, SI, and MSI (all log-rank p ≤ 0.013). Conclusions: Post-CPB SBP, MBP, SI, and MSI showed significant adjusted associations with 30-day mortality and may assist in early postoperative risk stratification. These exploratory findings require external validation, and the identified thresholds should not be interpreted as treatment targets.