Extracorporeal membrane oxygenation as a bridge to pulmonary transplantation

Acute clinical deterioration preceding death is a common observation in patients with advanced interstitial lung disease and secondary pulmonary hypertension. Patients with pulmonary arterial hypertension refractory to medical therapy are also at risk of sudden cardiac death (cor pulmonale). The treatment of these patients remains complex, and the findings from retrospective studies have suggested that intubation and mechanical ventilation are inappropriate given the universally poor outcomes. Extracorporeal support technologies have received limited attention because of the presumed inability to either recover cardiopulmonary function in the patient with end-stage disease or the presumed inability to proceed to definitive therapy with transplantation.

A retrospective review was performed of 31 patients from 2 institutions placed on extracorporeal membrane oxygenation as a bridge to lung transplantation compared with similar patients without extracorporeal membrane oxygenation at the same institutions and comparison groups queried from the United Network for Organ Sharing database.

We have transplanted 31 patients with refractory lung disease from mechanical artificial lung support. Of the 31 patients, 19 were ambulatory at transplantation. Pulmonary fibrosis (42%), cystic fibrosis (20%), and pulmonary hypertension (16%) were the most common diagnostic codes and acute cor pulmonale (48%) and hypoxia (39%) were the most common indications for device deployment. The average duration of extracorporeal membrane oxygenation support was 13.7 days (range, 2-53 days), and the mean survival of all patients bridged to pulmonary transplantation was 26 months (range, 54 days to 95 months). The 1-, 3-, and 5-year survival was 93%, 80%, and 66%, respectively. The duration of in-house postoperative transplant care ranged from 12 to 86 days (mean, 31 days). Patients requiring an extracorporeal membrane oxygenation bridge had comparable survival to that of the high acuity patients transplanted without extracorporeal membrane oxygenation support in the Scientific Registry of Transplant Recipients database but were at a survival disadvantage compared with the high-acuity patients (lung allocation score, >50) transplanted at the same center who did not require mechanical support (P < .001).

These observations challenge current assumptions about the treatment of selected patients with end-stage lung disease and suggest that "salvage transplant" is both technically feasible and logistically viable. Widespread adoption of artificial lung technology in lung transplant will require the design of clinical trials that establish the most effective circumstances in which to use these technologies. A discussion of a clinical trial and reconsideration of current allocation policy is warranted.