Hypoalbuminemia and Albumin Replacement during Extracorporeal Membrane Oxygenation in Patients with Cardiogenic Shock

Abstract

Background: Extracorporeal membrane oxygenation (ECMO) has been widely used in patients with cardiorespiratory failure. The serum albumin level is an important prognostic marker in critically ill patients. We evaluated the efficacy of using pre-ECMO serum albumin levels to predict 30-day mortality in patients with cardiogenic shock (CS) who underwent venoarterial (VA) ECMO.

Methods: We reviewed the medical records of 114 adult patients who underwent VA-ECMO between March 2021 and September 2022. The patients were divided into survivors and non-survivors. Clinical data before and during ECMO were compared.

Results: Patients' mean age was 67.8±13.6 years, and 36 (31.6%) were female. The proportion of survival to discharge was 48.6% (n=56). Cox regression analysis showed that the pre-ECMO albumin level independently predicted 30-day mortality (hazard ratio, 0.25; 95% confidence interval [CI], 0.11-0.59; p=0.002). The area under the receiver operating characteristic curve of albumin levels (pre-ECMO) was 0.73 (standard error [SE], 0.05; 95% CI, 0.63-0.81; p<0.001; cut-off value=3.4 g/dL). Kaplan-Meier survival analysis showed that the cumulative 30-day mortality was significantly higher in patients with a pre-ECMO albumin level ≤3.4 g/dL than in those with a level >3.4 g/dL (68.9% vs. 23.8%, p<0.001). As the adjusted amount of albumin infused increased, the possibility of 30-day mortality also increased (coefficient=0.140; SE, 0.037; p<0.001).

Conclusion: Hypoalbuminemia during ECMO was associated with higher mortality, even with higher amounts of albumin replacement, in patients with CS who underwent VA-ECMO. Further studies are needed to predict the timing of albumin replacement during ECMO.

Keywords: Albumin; Cardiogenic shock; Extracorporeal membrane oxygenation.

Fig. 1

Cox proportional hazard regression for pre-extracorporeal membrane oxygenation (ECMO) risk factors associated with 30-day mortality in patients with cardiogenic shock during ECMO support. SAVE, Survival After Venoarterial Extracorporeal Membrane Oxygenation; HCO₃-, bicarbonate; Hgb, hemoglobin; K, potassium; HR, hazard ratio; CI, confidence interval. **p<0.01.

Fig. 2

Comparison of receiver operating characteristic (ROC) curves among albumin-related parameters for the prediction of 30-day mortality. The area under the ROC curve of albumin (pre- extracorporeal membrane oxygenation [ECMO]) levels was 0.73 (standard error [SE], 0.05; 95% confidence interval [CI], 0.63–0.81; p<0.001; cut-off value=3.4 g/dL). The area under the ROC curve of albumin (mean value within initial 48 hours of ECMO) levels was 0.62 (SE, 0.05; 95% CI, 0.53–0.71; p=0.02; cut-off value=3.1). The area under the ROC curve of albumin levels (mean value during intra-ECMO) was 0.62 (SE, 0.05; 95% CI, 0.53–0.71; p=0.021; cut-off value=3.2). The area under the ROC curve of the amount of albumin infused (adjusted levels) was 0.74 (SE, 0.05; 95% CI, 0.65–0.81; p<0.001; cut-off value=4.8).

Fig. 3

Cumulative incidence of 30- day mortality from the time of extracorporeal membrane oxygenation (ECMO) initiation. Survival analysis with cumulative 30-day mortality incidence from the time of ECMO initiation. Patients with pre-ECMO albumin levels of less than 3.4 g/dL had a lower survival probability (p<0.001) than patients with pre- ECMO albumin levels of more than 3.4 g/dL.

Fig. 4

Probability regression between albumin infusion and 30-day mortality. This figure showed a correspondence between the adjusted amount of albumin infused and the possibility of 30-day mortality. As the adjusted amount of albumin infused increased, the possibility of 30-day mortality also increased (coefficient=0.140; standard error, 0.037; p<0.001).