[Extracorporeal membrane oxygenation as a bridge to lung transplantation]

To evaluate the effect of extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (LTx).

The clinical data of 18 patients with end-stage lung diseases was retrospectively reviewed, using ECMO as a bridge to LTx in intensive care unit of Affiliated Wuxi People's Hospital from January 2015 to December 2017. Clinical parameters were obtained from these patients, including gender, age, primary disease, preoperative lactate level, preoperative leukocyte, operation modality (unilateral or bilateral), type of ECMO, ECMO support time as a bridge to LTx, ECMO support time after operation, total usage time of ECMO, ECMO associated complications, primary graft dysfunction (PGD), successful ECMO weaning, and survival. Patients were divided according to type of ECMO, whether successfully weaned from ECMO or not, and primary disease. Clinical data was compared, and the Kaplan-Meier survival of 180-day was studied.

(1) The overall situation showed: A total of 18 patients were enrolled, with 14 males and 4 females, age ranged from 23 to 78 years old. Primary disease included 6 cases of idiopathic pulmonary fibrosis (IPF), 3 cases of idiopathic pulmonary hypertension (IPAH), 8 cases of interstitial pneumonia and 1 case of silicosis. Nine patients received venous-venous (V-V) ECMO and 9 venous-artery (V-A) ECMO as a bridge to LTx; 15 patients received LTx successfully, and failed in 3 cases. The average bridge time was 57.5 (14.5, 116.5) hours. ECMO associated complications included 6 cases with bleeding, 12 cases with renal failure, 2 cases with thrombosis, 2 cases with oxygenator leak, and 1 case with leg ischemia. There were 7 unilateral (5 right lungs and 2 left lungs) and 8 bilateral LTx. Three patients died before LTx due to septic shock. Nine patients died after LTx, 4 for septic shock, 4 for multiple organ failure, and 1 for sudden cardiac death. Six patients survived after LTx. (2) Group comparison showed: There was no significant difference in gender, age, ECMO support time as a bridge to LTx, ECMO support time after operation, total ECMO usage time, incidence of PGD, successful weaning from ECMO, and 180-day survival rate between V-V ECMO group (n = 7) and V-A ECMO group (n = 8). There was no significant difference in gender, age, primary disease, type of ECMO, operation modality, preoperative leukocyte count between groups of successfully weaned from ECMO (n = 11) and the failed (n = 7). Lower level of preoperative lactate acid (mmol/L: 3.01±1.51 vs. 8.27±3.49, t = -3.770, P = 0.006), shorter total ECMO usage time (hours: 72.82±40.53 vs. 210.71±107.10, t = -3.907, P = 0.001), and higher 180-day survival rate (54.5% vs. 0, P = 0.038) were found in the group of successfully weaned from ECMO, when compared with the failed group. (3) Kaplan-Meier survival analysis showed that postoperative survival rates of 7, 30, 60, and 180 days of 18 patients was 72.2%, 38.9%, 33.3%, and 33.3%, respectively. Among them, the postoperative survival rates of 7, 30, 60, and 180 days in the group of successfully weaned from ECMO (n = 11) were higher than those in group of failed (n = 7; 81.8% vs. 57.1%, 63.6 % vs. 0, 54.5% vs. 0, 54.5% vs. 0, respectively; log-rank test: χ² = 8.009, P = 0.005). The postoperative survival rates of 7, 30, 60, and 180 days in IPF group (n = 6) were lower than those in non-IPF group (n = 12; 33.3% vs. 83.3%, 16.7% vs. 50.0%, 16.7% vs. 41.7%, 16.7% vs. 41.7%; log-rank test: χ² = 4.161, P = 0.041).

The use of ECMO as a bridge to LTx may provide survival benefit for LTx recipients. V-V ECMO provides effective life support for patients without severe heart failure, and V-A ECMO for patients with unstable hemodynamics. Preoperative lactate level and total ECMO duration time were closely related to ECMO weaning rate. Primary diagnosis may affect prognosis.