Predictive value of ventriculo-arterial coupling for hypotension after induction of anaesthesia: a prospective observational cohort study

BACKGROUND: Post-induction hypotension (PIH) is associated with acute perioperative organ injury. We quantified the added value of echocardiographic parameters and ventriculo-arterial coupling (VAC)-related variables for the prediction of PIH. METHODS: ) was derived pre-operatively using transthoracic echocardiography combined with non-invasive blood pressure measurements. PIH was defined as the first occurrence of mean arterial pressure < 65 mmHg between anaesthesia induction and surgical incision. Predictors were analysed using a generalised additive model to account for potential non-linear associations. Incremental prognostic value was assessed using the fraction of new information (FNI), a reclassification-based metric, and changes in the area under the receiver operating characteristic curve (AUC). RESULTS: ratio > 1 was associated with PIH (OR 2.95; 95% CI 1.08-8.03; p = 0.034). The clinical model showed an AUC of 0.720 (95% CI 0.669-0.771). The addition of echocardiographic parameters increased the AUC to 0.768 (95% CI 0.720-0.816; Holm-adjusted p = 0.018) and provided 37% FNI (Holm-adjusted p = 0.199). The incorporation of VAC-related variables further increased the AUC to 0.785 (95% CI 0.739-0.831; Holm-adjusted p = 0.002) and yielded 46% FNI (Holm-adjusted p = 0.030). Compared with the clinical-echocardiographic model, incorporation of VAC-related variables provided an additional 14% FNI (Holm-adjusted p = 0.018) without a statistically significant AUC increase (0.017; 95% CI -0.004-0.039; Holm-adjusted p = 0.199). CONCLUSION: ratio > 1. Incorporation of echocardiographic parameters improved the discriminatory performance of a clinical prediction model, and the further addition of VAC-related variables provided meaningful improvement in risk reclassification, despite only modest gains in overall discrimination.