A Novel Clinical Risk Score to Predict Vasoplegia After Adult Cardiac Surgery

Vasoplegia is a morbid complication after cardiopulmonary bypass. Identifying patients at risk for vasoplegia may improve outcomes, but current assessment tools are limited by highly heterogeneous and static criteria for defining vasoplegia. Using a more rigorous definition, the study investigators developed a risk score that stratifies risk for vasoplegia after cardiopulmonary bypass.

Postoperative data were extracted from electronic health records of adult patients who underwent surgery with cardiopulmonary bypass at Baylor St. Luke's Medical Center (Houston, TX) from 2017 to 2022. Vasoplegia was defined as an hourly average mean arterial pressure ≤65 mm Hg, cardiac index ≥2.2 L/min/m², norepinephrine equivalents ≥0.1 μg/kg/min, and central venous pressure ≤15 mm Hg for at least 1 hour postoperatively. After merging electronic health record data with institutional elements of The Society of Thoracic Surgery registry, regression coefficients of significant variables were used to assign integer points to a risk score that was then internally validated.

The overall incidence of postoperative vasoplegia was 16.7%. Vasoplegic patients had higher rates of in-hospital mortality (6.4% vs. 3.0%, p<0.001) and major morbidity (51.5% vs. 23.4%, p<0.001) compared to non-vasoplegic patients. We developed a risk score comprising the independent predictors of vasoplegia. Patients were divided into risk categories according to total score. The probability of vasoplegia was 3.9%, 14.8%, and 34.2% in patients with low, moderate, and high scores, respectively. The risk score performed well on internal validation (C-index: 0.68 [95% CI: 0.64-0.72]).

This clinical risk score has the potential to inform clinical decision-making by identifying high-risk patients and enabling timely intervention.