Extracorporeal membrane oxygenation as a bridge to transplant in severe pulmonary hypertension

Severe pulmonary hypertension (PH) is the leading indication for a lung transplant in younger patients. Despite the availability of validated risk scores, their influence on lung allocation has been negligible, with continued reliance on decompensation and bridging with extracorporeal membrane oxygenation (ECMO).This single-centre, retrospective study assessed outcome of ECMO bridging in lung transplant for PH and evaluated short-term predictability of ECMO bridging.

Patients with PH listed for a lung transplant between January 2010 and March 2023 were included. Peri- and postoperative courses were compared dependent upon ECMO bridging status. Bridging risk analysis within 90 days of re-evaluation included patients not requiring ECMO at listing, with listing parameters evaluated using a univariate Cox proportional hazard regression.

A total of 114/123 patients listed underwent lung transplant. Twenty-eight required ECMO bridging. No differences in primary graft dysfunction grade 3 at 72 h (30 vs 20%; P = 0.28) or graft survival (1 year: 82 vs 88%; 5 years: 54 vs 59%; P = 0.84) were evident. ECMO bridging resulted in longer intensive care unit stays post-transplant (P = 0.002) and higher rates of both re-thoracotomy (P = 0.049) and vascular complications (P = 0.031). Factors increasing 90-day ECMO risk included N-terminal pro-B-type natriuretic peptide (P < 0.001), 6-min walk distance (P = 0.03) and O2 requirement at rest (P = 0.006).

Lung transplant survival outcomes are not affected by ECMO bridging in patients with severe PH. It does, however, expose patients to additional risk, and efforts such as easy-to-measure parameters to pre-emptively identify patients requiring bridging to assist with effective allocation should be encouraged.