Addition of albumin to Traditional Risk Score Improved Prediction of Mortality in Individuals Undergoing Transcatheter Aortic Valve Replacement

Objectives: The ability of the Society of Thoracic Surgeons (STS) and European System for Cardiac Operative Risk Evaluation (EuroSCORE)-2 scores to predict outcomes after transcatheter aortic valve replacement (TAVR) is insufficient. Frailty and serum albumin as a frailty marker were shown to correlate with prognosis after TAVR. We sought to evaluate the additive value of serum albumin to STS and EuroSCORE-2 scores to predict mortality in individuals undergoing TAVR.

Design: Retrospective analysis.

Setting: Tertiary-care hospital prospective registry.

Participants: Individuals who underwent TAVR (N = 426).

Measurements: We compared survival rates according to median baseline albumin levels (4 g/dL), STS score (4.5%), and EuroSCORE-2 (3.45%). Participants were divided into four groups according to median serum albumin and median STS and EuroSCORE-2 scores (high vs low), and 1-year survival rates were compared. A category-free net reclassification index (NRI) was calculated to compare the ability of a model of STS or EuroSCORE-2 alone to classify mortality risk with and without the addition of baseline serum albumin.

Results: Participants with low albumin levels had higher mortality (hazard ratio (HR) = 3.03, 95% confidence interval (CI) = 1.66-5.26, P < .001). Participants with low serum albumin and a high STS (HR = 4.55, 95% CI = 2.21-9.38, P < .001) or EuroSCORE-2 (HR = 2.72, 95% CI = 1.48-5.06, P = .001) score had higher mortality. Using NRI analysis, a model that included albumin in addition to STS correctly reclassified 42% of events (NRI = 0.58) and a model that included albumin in addition to EuroSCORE-2 correctly reclassified 44% of events (NRI = 0.64).

Conclusion: Serum albumin, as a marker of frailty, can significantly improve the ability of STS and EuroSCORE-2 scores to predict TAVR-related mortality.