Individualized Cardiac Index–Guided Hemodynamic Therapy in High-Risk Patients Undergoing Elective Major Abdominal Surgery

Importance It remains unclear if intraoperative hemodynamic therapy should be guided by cardiac index. Objective To evaluate whether individualized cardiac index–guided hemodynamic therapy vs routine hemodynamic therapy improves outcomes in high-risk patients undergoing elective major abdominal surgery. Design, Setting, and Participants This multicenter, single-blind, superiority randomized clinical trial enrolled high-risk patients undergoing elective major abdominal surgery between October 8, 2023, and October 25, 2025, at 12 university medical centers in Austria, the Czech Republic, Denmark, Germany, and Spain. The date of last follow-up was January 15, 2026. Interventions Patients were randomized to individualized cardiac index–guided hemodynamic therapy targeting the patient’s preoperative resting cardiac index vs routine hemodynamic therapy (with blinded cardiac index monitoring). Main Outcomes and Measures The primary outcome was a composite of acute kidney injury, acute myocardial injury, severe infectious complications, nonfatal cardiac arrest, or death within the first 7 postoperative days. Secondary outcomes included the individual components of the primary outcome within the first 7 postoperative days. Results Of the 1128 patients enrolled, 1111 were randomized and 1095 were included in the primary analysis (median age, 67 years [IQR, 59-74 years]; 49.4% were female). The primary outcome occurred in 243 of 549 patients (44.3%) in the individualized cardiac index–guided hemodynamic therapy group vs 256 of 546 patients (46.9%) in the routine hemodynamic therapy group (relative risk, 0.94 [95.1% CI, 0.83-1.08]; P = .38). There were no between-group differences for the incidence of the individual components of the primary outcome within the first 7 postoperative days. Conclusions and Relevance Among high-risk patients undergoing elective major abdominal surgery, individualized cardiac index–guided hemodynamic therapy targeting the patient’s preoperative resting cardiac index did not reduce the incidence of a composite outcome of acute kidney injury, acute myocardial injury, severe infectious complications, nonfatal cardiac arrest, or death within the first 7 postoperative days compared with routine hemodynamic therapy. Trial Registration ClinicalTrials.gov Identifier: NCT05648279