Echocardiographic Predictors of Successful Extracorporeal Membrane Oxygenation Weaning After Refractory Cardiogenic Shock

Background: Limited data are available regarding echocardiographic predictors for successful weaning from venoarterial (VA) extracorporeal membrane oxygenation (ECMO). We sought to determine whether echocardiographic parameters during ECMO flow study could predict successful weaning from ECMO.

Methods: A total of 92 ECMO patients from a multicenter ECMO registry underwent VA-ECMO flow study with transthoracic echocardiography before a weaning trial. During VA-ECMO flow study, flow was decreased by 30%-50% of the initial flow for 15 minutes, and echocardiography was performed both at baseline and after flow reduction. Changes of echocardiographic parameters were compared between the successful and failed weaning group.

Results: Sixty-four of the 92 patients were able to be weaned from VA-ECMO successfully. During VA-ECMO flow study, both lateral e' and tricuspid annular S' velocity improved significantly in the successful weaning group, while such findings were not observed in the failed weaning group. From univariable analysis, left heart decompression, improvement of lateral e' velocity, and improvement of tricuspid annular S' velocity showed significant association with successful VA-ECMO weaning. Predictability of the model with the change of lateral e' and tricuspid annular S' according to the reduction of ECMO flow for successful weaning from VA-ECMO is much higher than that of the model with conventional echocardiographic predictors from previous studies (left ventricular ejection fraction > 20%-25%, left ventricular time-velocity integral ≥ 10 cm, mitral annulus S' ≥ 6 cm/sec).

Conclusions: Improvement of lateral e' velocity and tricuspid annular S' velocity during VA-ECMO flow study may better represent cardiac reserve from a recovering heart than conventional echocardiographic parameters at minimal flow. Assessment of tissue Doppler parameters during ECMO flow study is a simple and feasible method to guide physicians on the optimal time to wean from ECMO.