Patients supported with peripheral femoral venoarterial extracorporeal membrane oxygenation (VA-ECMO) frequently face the challenge of determining the optimal timing for weaning trials, as no universally standardized bedside method is currently available for real-time assessment of native cardiac recovery. According to the Extracorporeal Life Support Organization (ELSO) guidelines, weaning decisions rely heavily on bedside echocardiography to evaluate cardiac function, particularly left ventricular outflow tract velocity-time integral (LVOT VTI). However, echocardiography is inherently intermittent, operator-dependent, and may lack the consistency required for continuous monitoring in the dynamic ICU setting [1, 2].

In our clinical observations, we identified a simple hemodynamic signal during native cardiac recovery in patients receiving peripheral femoral VA-ECMO: the left radial arterial pressure waveform gradually recovered in both amplitude and morphology and became nearly concordant with the right radial arterial waveform, accompanied by concordant arterial blood gas (ABG) values from both sites. In these patients, subsequent echocardiographic assessment frequently demonstrated LVOT VTI values that met or exceeded commonly used thresholds for VA-ECMO weaning assessment, typically ≥ 10–12 cm. We therefore propose that bilateral radial arterial pressure monitoring, combined with bilateral ABG comparison, may serve as a low-invasive, real-time bedside signal to facilitate early recognition of native cardiac recovery and to prompt formal echocardiographic weaning evaluation.

Physiologically, in femoral VA-ECMO, oxygenated blood is delivered retrogradely into the descending aorta, whereas recovering native left ventricular ejection generates antegrade pulsatile flow from the ascending aorta. During early support, native left ventricular ejection is often minimal, resulting in asymmetric arterial pressure transmission across the aortic arch. The right radial artery, supplied through the brachiocephalic trunk, is commonly used to monitor upper-body perfusion, whereas the left radial artery may better reflect propagation of native pulsatile pressure. As left ventricular function recovers, antegrade output progressively overcomes retrograde ECMO flow, leading to bilateral radial arterial pressure and waveform concordance. When confirmed by concordant bilateral ABG values, this signal may indicate clinically meaningful native cardiac output and correlate with ELSO-recommended echocardiographic readiness for weaning (Fig. 1A).