Results
Among the 781 patients of the PC-ECMO registry, 56 patients (7.2%) were excluded from the present analysis because of lack of data on arterial lactate levels before starting VA-ECMO support. A total of 725 patients over 2378 days of VA-ECMO were included in the final analysis. Their mean age was 62.9 ± 12.9 years (range: 18.4-86.7 years), and 232 (32.0%) were female. The mean duration of VA-ECMO was 7.1 ± 6.3 days (median: 5.0 days; range: 0-39 days), and 39.4% patients were supported for ≤3 days, 29.1% for 4-7 days, 15.3% for 8-10 days, and 20.7% for > 10 days (Figure 1). The different groups of VA-ECMO duration exhibited similar baseline, demographic and operative characteristics (Table 1). However, VA-ECMO duration ≤3 days was associated with a higher metabolic derangement, as expressed by the arterial lactate level before VA-ECMO institution (8.2±5.4 vs 6.5±4.3 vs 6.1±4.0 vs 6.1±4.0, P < .0001) (Figure 2).
A total of 391 (53.9%) patients were successfully weaned from VA-ECMO and, among those, 134 (34.3%) died prior to discharge. Hospital survival increased from 8.1% on day 1 to 55% on day 5. Multivariable logistic regression adjusted for the PC-ECMO score and participating centers showed that prolonged duration of VA-ECMO therapy (4-7 days, adjusted rate 53.6%, odds ratio [OR] 0.28, 95% confidence interval [CI] 0.18-0.44; 8-10 days, adjusted rate 61.3%, OR 0.51, 95% CI 0.29-0.87; and >10 days, adjusted rate 59.3%, OR 0.49, 95% CI 0.31-0.81) was associated with a lower risk of mortality compared with VA-ECMO lasting ≤3 days (adjusted rate 78.3%) (Figure 3).
However, patients requiring VA-ECMO therapy for 8-10 days (adjusted OR 1.955, 95% CI 1.149-3.326) and >10 days (adjusted OR 1.854, 95%CI 1.139-3.020) had a significantly increased risk of hospital mortality compared to those who were on VA-ECMO therapy for 4-7 days. In addition, VA-ECMO support longer than 7 days was associated with a significantly increased risk of re-exploration for bleeding, blood transfusion requirements, renal failure requiring renal replacement therapy, deep sternal wound infection, bloodstream infection and pneumonia (Table 2).