Echocardiographic evaluation of ventricular performance in VA-ECMO weaning: results from a observational monocentric prospective study
Authors: Tavazzi G , Colombo C N J , Erba M , Dammassa V , Perotti L , Klersy C , Pellegrini C , Civardi L , Camporotondo R , Price S 
Published: October 2024

Abstract

Background
Although temporary mechanical circulatory support (MCS) devices are increasingly used in the management of cardiogenic shock (CS), several open question regarding the kind of support and timing of institution/weaning remains open. Echocardiography is widely applied to drive the weaning process and decision although there are no standardized protocols for the trial nor accordance on the parameters to apply.

Purpose
We sought to evaluate the overall accuracy of echocardiographic indices in predicting successful weaning from VA ECMO in patients with CS. Specifically, we tested total isovolumic time (tIVT), an index of ventricular performance, and longitudinal function (MAPSE) on top of the commonly used parameters (left ventricular ejection fraction, LVEF; left ventricular velocity time integral, LV VTI; TAPSE; right ventricular S’ at tissue Doppler imaging, RV S’).

Methods
Monocentric prospective study on adults receiving VA-ECMO due to refractory CS and/or cardiac arrest (CA) from 2012 to 2020. Echocardiography was performed at VA-ECMO placement and during the weaning trials. Weaning trials were performed daily, starting 48 hours after VA-ECMO institution, when patients were hemodynamically stable: mean arterial pressure &gt;65 mmHg, no or minimum adrenergic support (vasoactive inotropic score &lt;10), heart rate &lt;110 bpm, lactate &lt;2 mmol/L, and no signs of respiratory distress. Weaning trials were performed with a stepwise decrease of VA-ECMO blood flow until reaching 1 or 1.5 L/min under adequate anticoagulation. Successful weaning was defined as removal of VA-ECMO with no requirement for further MCS in the following 30 days.

Results
76 patients were enrolled (23.8% female, 54.2±10.6 years-old), 52.6% due to CA. Median duration of VA-ECMO was 58 hours; 47 (61.8%) had intra-aortic balloon pump (IABP) inserted upfront. In-hospital mortality was 62.4% overall, 40% for CS without CA. 6 of the 32 weaned patients died for multiorgan failure due to septic shock. The baseline echocardiographic parameters associated with successful weaning were (table): stroke volume &gt;13.9 mL (p 0.002), tIVT &gt;23.6 min/sec (p 0.053), LV VTI &gt;6.6 cm (p&lt;0.001), MAPSE &gt;6.15 mm (p 0.001), TAPSE &gt;11 mm (p 0.023), RV S’ &gt;10 cm/s (p 0.012). LVEF did not reach the statistical significance. Figure shows Kaplan-Meier analysis on echocardiographic indices collected at time of cannulation (panel A) and during the last weaning trial (panel B).

Conclusions
Echocardiography is pivotal in defining cardiac recovery and monitoring the weaning trial. Indices reflecting ventricular performance and delivered flow from LV were associated with weaning success both at VA-ECMO institution and throughout the weaning trials. Considering the known limitations of LVEF (heart rate, loading and left ventricular dyssynchrony dependence), tIVT and MAPSE should be introduced in the standard evaluation of patients in the acute setting.TableFigure