Early Postoperative Hypoalbuminemia Predicts Mortality and “Days Alive and Out of Hospital” after Orthotopic Heart Transplantation

Background: Postoperative hypoalbuminemia is frequent after cardiac surgery and results from blood loss, dilution or capillary leak amongst others. In patients undergoing heart transplantation (HTX) preoperative liver impairment and consequent hypoalbuminemia is associated with increased mortality, but the role of early postoperative hypoalbuminemia is unclear. This study investigated associations between early postoperative hypoalbuminemia and 1-year mortality as well as “days alive and out of hospital” (DAOH) after HTX.

Methods: This retrospective cohort study included patients who underwent HTX at the University Hospital Duesseldorf, Germany between 2011 and 2021. The main exposure was serum albumin concentration at ICU. The primary endpoints were mortality and DAOH within one year after surgery. Albumin levels were compared between survivors and nonsurvivors using unpaired t-tests. Receiver Operating Characteristic (ROC) curve analysis, logistic regression model and linear regression with adjustment for the “Model for End-stage Liver Disease” (MELD) score were performed.

Results: Out of 231 patients screened, 212 were included into analysis (mean age 55 ± 11 years, 73% male). One-year mortality was 19.7% (40 patients) and median DAOH were 298 (229–322). Postoperative serum albumin was higher in survivors as compared with nonsurvivors (3.3 ± 0.5 g/dl vs. 2.8 ± 0.6 g/dL; p < 0.0001). ROC analysis showed good discrimination for mortality by postoperative serum albumin after HTX [AUC = 0.74 95% CI: 0.66–0.83]. According to Youden Index, the cut-off for serum albumin at arrival ICU and mortality was 3.0 g/dl. In univariate analysis DAOH were lower in patients with albumin below cutoff [albumin >3.0 g/dL: 310 (268–326) days versus albumin < 3.0 g/dl: 253 (0–305) days]. After adjustment for MELD-score multivariate logistic and linear regression showed independent associations between hypoalbuminemia and mortality/DAOH with odds ratio of 4.57 [95% CI 2.23–9.35] and unstandardized regression coefficient of −73.47 [95% CI −101.23 to −45.70], respectively.

Conclusion: Postoperative hypoalbuminemia <3.0 g/dL is associated with 1-year mortality and poor DAOH after HTX. The role of early postoperative albumin substitution as therapeutic approach needs further investigation.

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Artikel online veröffentlicht:
13. Februar 2024