Advanced Age as a Predictor of Survival and Weaning in Venoarterial Extracorporeal Oxygenation: A Retrospective Observational Study

Abstract

Background. In most reports on ECMO treatment, advanced age is classified as a contraindication to VA ECMO. We attempted to investigate whether advanced age would be a main risk factor deciding VA ECMO application and performing VA ECMO support. We determined whether advanced age should be regarded as an absolute or relative contraindication to VA ECMO and could affect weaning and survival rates of VA ECMO patients. Methods. VA ECMO was performed on 135 adult patients with primary cardiogenic shock between January 2010 and December 2014. Successful weaning was defined as weaning from ECMO followed by survival for more than 48 hours. Results. Among the 135 patients, 35 survived and were discharged uneventfully, and the remaining 100 did not survive. There were significant differences in survival between age groups, and older age showed a lower survival rate with statistical significance (P = .01). By multivariate logistic regression analysis, age was not significantly associated with in-hospital mortality (P = .83) and was not significantly associated with VA ECMO weaning (P = .11). Conclusions. Advanced age is an undeniable risk factor for VA ECMO; however, patients of advanced age should not be excluded from the chance of recovery after VA ECMO treatment.

Figure 1

Kaplan-Meier curves for the cumulative survival probability of a pre-ECMO age. To predict in-hospital mortality according to age, patients were divided into 4 groups according to age: group I (age < 50, n = 31), group II (50 ≤ age < 60, n = 27), group III (60 ≤ age < 70, n = 31), and group IV (70 ≤ age, n = 46). Comparison of survival curves with the log-rank test: chi-square test x² = 11.2779, df = 3, P = .0103. Mean, standard error, and 95% confidence intervals for the mean are summarized in Table 2. Comparison of survival probabilities at 6, 10, and 30 days after ECMO initiation with the log-rank test and hazard ratios with 95% confidence intervals is also summarized in Tables 2 and 4. Overall mean survival rate was 25.9%, 6-day survival rate was 50%, 10-day survival rate was 40.7%, and 30-day survival rate was 27.3%.

Figure 2

Kaplan-Meier curves for the cumulative ECMO weaning probability of a pre-ECMO age. To predict in-hospital mortality according to age, patients were divided into 4 groups: group I (age < 50, n = 31), group II (50 ≤ age < 60, n = 27), group III (60 ≤ age < 70, n = 31), and group IV (70 ≤ age, n = 46). Comparison of survival curves with the log-rank test: chi-square test x² = 5.9915, df = 3, P = .1120. Mean, standard error, and 95% confidence intervals for the mean are summarized in Table 2. Comparison of ECMO weaning probabilities at 48, 72, and 192 hours after ECMO initiation with the log-rank test and hazard ratios with 95% confidence intervals is also summarized in Tables 2 and 4. Overall mean ECMO weaning rate was 39.20%, 8-day mean ECMO weaning rate was 50%, 10-day mean ECMO weaning rate was 45.8%, and 30-day mean ECMO weaning rate was 37.4%.