Prospective validation and refinement of the APPROACH cardiovascular surgical intensive care unit readmission score

Abstract

PurposeThe APPROACH cardiovascular surgical intensive care unit (CVICU) readmission score has excellent discrimination and calibration for CVICU readmission after discharge to a surgical ward; however, it has not been prospectively validated. Material and methodsIn a prospective consecutive cohort of 805 patients ≥18 years admitted to the CVICU after coronary artery bypass and/or valvular surgery, the APPROACH CVICU readmission score was calculated at the time of discharge to a surgical ward. The study compared observed versus predicted CVICU readmission and the model discrimination was evaluated using AUC c-index. The incremental prognostic utility of 6 pre-specified prospectively collected respiratory (re-intubation, tracheostomy, oxygen at discharge) and hemodynamic variables (heart rate, systolic blood pressure, inotropes at discharge) were tested using net reclassification index (NRI) and integrated discrimination improvement (IDI). ResultsA total of 37 (4.6%) patients were readmitted to the CVICU. The median CVICU length of stay (9.0 vs 2.0 days, p < .001) and all-cause in-hospital mortality (8.1% vs 0.4%, p < .001) was higher among readmitted patients. The model had good discrimination (c-index = 0.748). Systolic blood pressure at discharge yielded the largest improvement in model discrimination (c-index = 0.782; Hosmer-Lemshow p = .749). ConclusionsIn a prospective validation cohort, the APPROACH CVICU readmission risk score had good discrimination and could be operationalized in future research and clinical practice.