Intensive vs Conventional Intraoperative Blood Pressure Management on Cardiovascular Events After Major Abdominal Surgery: The BP-CARES Randomized Trial

Abstract

Background: Intraoperative hypotension is associated with cardiovascular complications after major noncardiac surgery, but randomized trials assessing whether intensive blood pressure management during surgery can reduce these complications have shown inconsistent results.

Objectives: The purpose of this study was to determine whether intensive intraoperative blood pressure management reduces the incidence of a composite of cardiovascular complications within 30 days after major abdominal surgery.

Methods: In this investigator-initiated parallel-group trial, patients at 3 Chinese sites were randomly assigned (1:1) to intensive blood pressure management targeting intraoperative MAP ≥80 mm Hg (intensive strategy group) or conventional management targeting intraoperative MAP ≥ the higher of 65 mm Hg or 60% of preoperative baseline pressure (conventional strategy group). We included patients aged ≥45 years who had known cardiovascular disease or cardiovascular risk factors and were scheduled for inpatient abdominal surgery expected to last at least 2 hours. The primary outcome was a composite of myocardial injury or infarction, new-onset clinically important arrhythmias, acute heart failure, stroke, cardiac arrest, and all-cause death within 30 days of surgery.

Results: Between June 30, 2020, and September 23, 2022, 1,500 patients were enrolled, of whom 1,477 were included in the modified intention-to-treat population (739 in the intensive strategy group and 738 in the conventional strategy group). Patients assigned to intensive intraoperative blood pressure management experienced a lower burden of hypotension exposure, as assessed by several measures. For example, the median cumulative duration of MAP <65 mm Hg was 1 minute (Q1-Q3: 0-7 minutes) in the intensive strategy group, compared with 8 minutes (Q1-Q3: 0-20 minutes) in the conventional strategy group. The primary composite outcome occurred in 107 of 739 patients (14.5%) in the intensive strategy group and 100 of 738 patients (13.6%) in the conventional strategy group (relative risk: 1.07; 95% CI: 0.83-1.38; P = 0.61).

Conclusions: In high-risk patients having major abdominal inpatient surgery, intensive intraoperative blood pressure management targeting a mean arterial pressure ≥80 mm Hg did not reduce the incidence of cardiovascular events compared with the conventional target of ≥65 mm Hg and 60% of the preoperative baseline.

Keywords: anesthesia; blood pressure; cardiovascular events; noncardiac surgery; randomized trial.