Extracorporeal life support as a bridge to lung transplantation

Outcomes and temporal trends among high-risk patients after lung transplantation in the United States

INTRODUCTION

Although several studies have evaluated risk factors for death after lung transplantation (LTx), few studies have focused on the highest-risk recipients. We undertook this study to evaluate the effect of high lung allocation scores (LAS), ventilator support, and extracorporeal membrane oxygenation (ECMO) support on outcomes after LTx.

METHODS

We retrospectively reviewed all LTx recipients in the United Network for Organ Sharing database. Primary stratification was by recipient acuity at the time of LTx. The 3 strata consisted of (1) recipients in the highest LAS quartile (LAS ≥ 48.4), (2) those requiring ventilator support, and (3) those requiring ECMO support. The primary outcome was 1-year mortality. Sub-group analysis focused on temporal trends.

RESULTS

From May 2005 to June 2011, 9,267 adults underwent LTx. Before LTx, 1,874 (20.2%) were in the highest LAS quartile, 526 (5.7%) required ventilator support, and 122 (1.3%) required ECMO support. Unadjusted analysis showed decreased 1-year survival associated with ventilator (67.7%) and ECMO support (57.6%) compared with the highest LAS quartile (81.0%; p < 0.001 for each comparison). These differences persisted on adjusted analysis for ventilator support (hazard ratio, 1.99, p < 0.001) and ECMO support (hazard ratio, 3.03; p < 0.001). Increasing annual center volume was associated with decreased mortality. In patients bridged to LTx with ECMO support, 1-year survival improved over time (coefficient, 8.03% per year; p = 0.06).

CONCLUSIONS

High-acuity LTx recipients, particularly those bridged with ventilator or ECMO support, have increased short-term mortality after LTx. However, since the introduction of the LAS, high-risk patients have demonstrated improving outcomes, particularly at high-volume centers.