Acute Lung Injury after Mechanical Circulatory Support Implantation in Patients on Extracorporeal Life Support: An Unrecognized Problem

OBJECTIVES:

We observed early acute lung injury (ALI) after a switch from veno-arterial extracorporeal life support (VA-ECLS) to long-term mechanical circulatory support (MCS). The aim of our study was to analyse the frequency, impact on mortality and characteristics of patients presenting ALI after MCS implantation in the bridge-to-bridge (BTB) strategy.

METHODS:

We retrospectively analysed data from 55 consecutive cardiogenic shock patients who underwent a BTB strategy between January 2004 and March 2012 in our centre. ALI was defined as severe acute respiratory failure (PaO2/FiO2 <200) with or without need for iterative VA-ECLS or veno-venous (VV)-exracorporeal membrane oxygenation (ECMO) occurring within 48 h of MCS implantation.

RESULTS:

ALI was observed in 15 of 55 (27%) patients. Eleven patients required VV-ECMO or VA-ECLS and 4 were treated medically. The median (interquartile range) duration of support under a long-term device was 47.5 (168.8) days. Mortality while on long-term support was significantly higher in patients who developed ALI (13 of 15, 87%) than in those who did not (21 of 40, 53%; P = 0.03). Hazard ratio for death while on support in patients who developed ALI when compared with those who did not was 3.390 (95% confidence interval, 1.636-7.026, P = 0.001). Univariate risk factors for postimplant ALI included: signs of pulmonary oedema while under extracorporeal life support (ECLS) during the week preceding long-term device implantation; mechanical ventilation, the incomplete recovery of renal and hepatic functions and the number of red blood cell units transfused at the time of long-term device implantation, and use of pulsatile, biventricular support.

CONCLUSIONS:

Implantation of a long-term MCS device in patients on ECLS can result in severe ALI, which is associated with ominous outcomes. Various preimplant risk factors for ALI have been identified and might allow devising strategies to prevent this complication.