Intraoperative hemodynamic imbalance quantification: clinical validation of heart rate to mean blood pressure ratio in predicting myocardial injury after noncardiac surgery

Background The effects of isolated heart rate (HR) and mean blood pressure (MBP) on myocardial injury after noncardiac surgery (MINS) have been investigated, but the combined impact of intraoperative HR and MBP remains unclear. This study aimed to assess the influence of the heart rate-mean arterial pressure ratio (HMR) on MINS to optimize hemodynamic management. Methods This retrospective cohort study included adult patients who underwent general anesthesia and postoperative troponin measurements at Meizhou People's Hospital. The primary exposure was the time-weighted area above the HMR threshold (1.0) (TWAAT-HMR > 1.0), and the primary outcome was MINS within one postoperative day. The diagnostic performance of TWAAT-HMR > 1.0, the time-weighted area under MBP < 60 mmHg, and the time-weighted area above HR > 100 bpm was evaluated using Receiver Operating Characteristic (ROC) analysis. Logistic regression and restricted cubic splines (RCS) were used to assess the association between HMR and MINS. Sensitivity analyses were conducted to confirm the robustness of the findings, and subgroup analyses examined potential interactions with age, sex, and body mass index. Results Among 699 patients, the incidence of MINS was 9.4%. TWAAT-HMR > 1.0 demonstrated superior predictive accuracy for MINS compared to time-weighted areas under/above MBP and HR (AUC: 0.708 vs. 0.646 and 0.640, respectively). TWAAT-HMR > 1.0 was identified as an independent risk factor for MINS (odds ratio [OR] = 1.71, 95% confidence interval [CI] 1.35-2.17, p < 0.001). RCS analysis showed a linear increase in MINS risk with rising HMR (p for non-linearity = 0.507). Sensitivity and subgroup analyses supported the primary findings. Conclusion Elevated HMR is associated with a higher risk of MINS in adults undergoing general anesthesia. HMR monitoring may serve as a valuable parameter for optimizing perioperative hemodynamic management.