Hypertension and Postoperative Outcomes: A Retrospective Cohort Study.

Background: The prevalence of hypertension is high. However, hypertensive patients often remain undiagnosed or poorly controlled, posing challenges for anesthesiologists before surgery. Although well-established guidelines have been proposed, some uncertainties remain. This study aimed to test the hypothesis that the closer the preoperative blood pressure (BP) is to normal, the lower the incidence of unfavorable postoperative outcomes in hypertensive patients using data from 2016 onward. Methods: Medical records of adult patients under general anesthesia for surgery at 68 hospitals in Japan between 2016 and 2021 were reviewed. In accordance with World Health Organization criteria, patients were categorized based on their maximum BP recorded the day before surgery into five groups: true normotension, controlled hypertension (patients with prior diagnosis and/or treatment of hypertension), and Stages 1, 2, and 3 hypertension groups. Postoperative mortality rates and incidence of unfavorable outcomes, including ischemic heart disease, cerebrovascular disease, aortic dissection, and acute renal failure, were compared using multivariable logistic regression analysis. Results: Data from 272,594 patients (either sex, aged between 20 and 106 years) were analyzed, excluding those undergoing cardiac, brain, and obstetric surgery. Mortality did not differ significantly between the four hypertension groups and the true normotension group. Compared with the true normotension group, the odds of ischemic heart disease were higher in the controlled, Stage 2, and Stage 3 hypertension groups. The odds of cerebrovascular disease and acute renal failure increased with hypertension stage, whereas the odds of aortic dissection were elevated only in Stage 3 hypertension. Conclusions: Our results showed that the closer preoperative BP was to normal, the better the postoperative outcomes for cerebrovascular disease and acute renal failure, but not for mortality, ischemic heart disease, or aortic dissection. Since the risk in the controlled hypertension group was higher than initially expected, our hypothesis was rejected.