Echocardiographic Prediction of Successful Weaning From Venoarterial Extracorporeal Membrane Oxygenation

Echocardiographic parameters for weaning from extracorporeal membrane oxygenation-the role of longitudinal function and cardiac time intervals

AIMS

Limited data exist on echocardiographic predictors of weaning from veno-arterial extracorporeal membrane oxygenation (V-A ECMO). We aimed to test the performance of different echocardiographic indices to predict weaning from V-A ECMO and free survival after weaning.

METHODS AND RESULTS

Observational study including patients with cardiogenic shock submitted to V-AECMO. Echocardiography was performed after V-AECMO placement and daily during the weaning trial to assess cardiac recovery. Echocardiography data after V-A ECMO implantation and during the last weaning trial before V-A ECMO removal were analysed. Besides traditional parameters, total isovolumic time (t-IVT, a left ventricular performance index) and mitral annular plane systolic excursion (MAPSE) were also tested. Seventy-six patients were included. A greater ventricular velocity time integral (LVOT VTI) at baseline was associated with a five-fold increase in weaning success (P < 0.001) as MAPSE lateral >6.15 mm (P = 0.001) did. TAPSE and S' at tricuspid annulus showed an analogous association. During the weaning trial t-IVT, LVEF, MAPSE, LVOT VTI, and TAPSE all improved significantly (P < 0.001 for all). At regression analysis t-IVT <14.4 s/min (<0.001), LVOT VTI >12.3 cm (P < 0.001), MAPSE > 8.9 mm (P < 0.001), TAPSE > 16 mm (<0.001), and E/e' < 15.5 (P = 0.001) were associated with weaning success and free survival after weaning. LVEF did not predict the weaning success and survival at any time-point (P = 0.230).

CONCLUSION

Longitudinal function, t-IVT and native ejection, measured with LVOT VTI, are reliable parameters to predict weaning success in V-A ECMO whereas the LVEF, although dynamically changing during weaning trial, it is not.

Aortic arch blood flow measurements as a predictor of successful ECMO weaning in cardiogenic shock

Objective

Acute cardiogenic shock is a life-threatening condition with mortality rates of up to 50%. If conventional therapy fails, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) therapy has emerged to a promising alternative for temporary cardiac and respiratory support in specialized centers. However, it is only a bridge to recovery, final decision, heart transplantation or the permanent implantation of a left ventricular assist device. Therefore, the identification of the optimum weaning time point is challenging, and standardized weaning protocols are rare.

Methods

In this explorative pilot study, we evaluated the potential benefit of blood flow measurements in the aortic arch using an ultrasonic cardiac output monitor (USCOM) for the primary endpoint of successful VA-ECMO weaning. 12 patients under VA-ECMO therapy for acute cardiogenic shock and a hemodynamic condition which qualified for a stepwise weaning process were included in this study. Main exclusion criterion was the presence of additional venting therapy for left ventricular unloading, e.g. Impella. Statistical comparisons were performed using the Mann-Whitney test and corrected for multiple testing by the Holm-Sidak method.

Results

Peak velocity of flow in the aortic arch showed a positive correlation with weaning success independent of ECMO flow (weaning success vs. failure: 0.75 vs. 0.35 m/s (low ECMO support), p = 0.049), whereas we identified only a trend for mean pressure gradient, minute distance and stroke volume index.

Conclusion

We hypothesize, that USCOM might provide an additive benefit to conventional strategies in its ability to predict successful VA-ECMO weaning and prevent pulmonary congestion. Larger upcoming trials are required to address this relevant topic and provide standardized treatment protocols for optimized weaning in the future.