Response to “Clinical Interpretation of Markedly Elevated First Intraoperative Systolic Blood Pressure in Non‐Cardiac Surgery”

Dear editor: We thank Drs. Yetim and Kalçik for their interest in our article “Relationship Between First Systolic Blood Pressure in the Operating Room and Perioperative Ischemic Stroke in Non-Brain Non-Cardiac Surgical Patients” and for their thoughtful comments. We appreciate the opportunity to address their methodological and interpretative concerns, which we respond to point-by-point below. Regarding the use of a single, non-invasive blood pressure measurement: We acknowledge that the first systolic blood pressure measured in the operating room (first-OR-SBP) may be influenced by situational factors such as anxiety, stress, or white-coat effect. However, our aim was to evaluate a pragmatic, routinely recorded clinical parameter that is immediately available to anesthesiologists and surgeons. While sustained hypertension and blood pressure trajectories are important, first-OR-SBP may serve as an early indicator of hemodynamic vulnerability. We agree that future studies incorporating repeated or continuous measurements would further clarify its role. Concerning the statistical determination of the 186 mmHg threshold: We agree that data-driven cutoffs carry a risk of overfitting. To mitigate this, we first used a cubic spline analysis to identify a non-linear relationship, followed by the minimum p-value approach within a pre-specified risk interval. The consistency of this threshold across multivariable and propensity score-matched models supports its robustness. While current guidelines suggest postponing surgery at SBP >180 mm Hg, our threshold of 186 mmHg may represent a more specific risk marker for perioperative ischemic stroke in this surgical population, and could prompt closer intraoperative monitoring. Regarding residual confounding and unmeasured factors such as blood pressure variability: We recognize that perioperative blood pressure variability (BPV) is an important contributor to stroke risk. Although our study adjusted for several intraoperative hemodynamic parameters, detailed BPV metrics were not available in our retrospective dataset—a limitation we explicitly acknowledged. We encourage future prospective studies to integrate BPV analysis to better understand its interaction with first-OR-SBP. Concerning potential under-ascertainment of stroke events: We agree that our observed incidence of perioperative ischemic stroke (0.19%) may be an underestimate due to the lack of systematic post-discharge neurological follow-up, a common limitation in retrospective studies. Nevertheless, the significant association we identified suggests that the true relationship may be even stronger. We support the call for prospective studies with structured neurological assessment to capture transient or subclinical events. General interpretation and clinical translation: We agree that our findings should be interpreted with caution and not used in isolation for clinical decision-making. Rather, they highlight first-OR-SBP as a potential risk marker that may help identify patients who could benefit from enhanced perioperative monitoring. We fully endorse the need for multicenter prospective studies with repeated blood pressure measurements, systematic neurological follow-up, and detailed hemodynamic profiling to validate and extend our results. Thank you again for engaging with our work and for contributing to this important discussion. Sincerely, Yan Zhou, Liqing Xu, Lin Liu, and Hongzhou Duan Peking University First Hospital, Beijing, China All of the authors contributed planning, writing, and revision. This research was supported by Peking University First Hospital Cross disciplinary Research Project (No. 2023IR15) and Peking University Clinical Scientist Training Program (BMU2025PYJH003). The authors declare no conflicts of interest. No new data was generated or analyzed in support of this letter to the editor.