Purpose: Detailed extracorporeal membrane oxygenation (ECMO) weaning strategies and specific predictors of ECMO weaning success are lacking. This study evaluated a weaning strategy following support for refractory cardiogenic shock to identify clinical, hemodynamic, and Doppler echocardiography parameters associated with successful ECMO removal.
Methods: Hemodynamically stable patients underwent ECMO flow reduction trials to <1.5 L/min under clinical and Doppler echocardiography monitoring. When a patient had partially or fully recovered from severe cardiac dysfunction, tolerated the weaning trial, and had left ventricular ejection fraction (LVEF) >20-25% and aortic time-velocity integral (VTI) >10 cm under minimal ECMO support, device removal was considered.
Results: Among the 51 patients (34 males, aged 54 ± 14 years) who received ECMO for medical (n = 27), postcardiotomy (n = 11), or posttransplantation (n = 5) cardiogenic shock, 38 tolerated at least one ECMO flow reduction trial and 20 were ultimately weaned. Compared with the 13 patients who tolerated the trial but were not deemed weanable, those successfully weaned had, at each ECMO flow level, higher arterial systolic and pulse pressures, VTI, LVEF, and lateral mitral annulus peak systolic velocity (TDSa). All weaned patients had aortic VTI ≥10 cm, LVEF >20-25%, and TDSa ≥6 cm/s at minimal ECMO flow support. These Doppler echocardiography parameters better separated weaned and nonweaned patients than any other parameters tested.
Conclusions: Patients who tolerated a full ECMO weaning trial and had aortic VTI ≥10 cm, LVEF >20-25%, and TDSa ≥6 cm/s at minimal ECMO flow were all successfully weaned. However, further studies are needed to validate these simple and easy-to-acquire Doppler echocardiography parameters as predictors of subsequent ECMO weaning success in patients recovering from severe cardiogenic shock.