How can we wean a patient from Impella (percutaneous left ventricular assist device) and veno‑arterial extracorporeal membrane oxygenation (VA ECMO)?

Weaning Impella + VA ECMO (ECPELLA Configuration)

General Weaning Strategy

The standard approach is to wean VA ECMO first while maintaining Impella support during the early stages of ECMO removal, followed by subsequent Impella weaning once cardiac function demonstrates adequate recovery. 1

Step-by-Step Weaning Protocol

1. Assessment for Readiness to Wean

Patients on nondurable mechanical circulatory support should always be evaluated for ventricular recovery, particularly in postcardiotomy shock, myocardial infarction, or myocarditis. 1

Assess the following clinical parameters before initiating weaning:

• Hemodynamic stability: Mean arterial pressure >65 mmHg, cardiac index >2.2 L/min/m², central venous pressure <12 mmHg 1
• Echocardiographic left ventricular function: Left ventricular ejection fraction improvement, reduced left ventricular end-diastolic pressure, adequate wall motion 1, 2
• Metabolic parameters: Normalized lactate levels, adequate mixed venous oxygen saturation 2
• End-organ function: Stable renal function (though note that ECPELLA patients have higher rates of renal replacement therapy requirement) 3, 4
• Minimal vasopressor requirements: Ideally weaned off inotropes before attempting device removal 5

2. ECMO Weaning (First Device to Remove)

The practice is to wean the patient off ECMO first while ensuring continued support with the Impella device during early stages of ECMO removal. 6

ECMO Weaning Trial Process:

• Gradually reduce ECMO flow while monitoring hemodynamics and arterial blood gases 6
• Maintain Impella at full support during ECMO flow reduction to provide left ventricular unloading and forward flow 5
• Monitor for adequate native cardiac output with serial echocardiography 1
• Typical ECMO duration: Median 7-8 days before successful weaning when combined with Impella 6, 5
• Time to ECMO removal after Impella placement: Approximately 22 hours median in one series 5

ECMO decannulation is significantly more feasible in patients with concomitant Impella support (72% vs 32% in ECMO-only patients). 3

3. Post-ECMO Period with Continued Impella Support

After ECMO removal, maintain Impella support for a period to allow further cardiac recovery and optimization. 5

• Duration of Impella support after ECMO removal: Median 17 days in bridge-to-LVAD patients, or 8 days total duration in recovery patients 6, 5
• During this period, patients can be mobilized and orally fed (88.9% of patients in one series), which is a major advantage over ECMO-only support 5
• This period allows for right ventricular function optimization before considering further interventions 5

4. Impella Weaning (Second Device to Remove)

Once adequate cardiac recovery is demonstrated, begin Impella weaning by gradually reducing pump speed (P-levels). 1

Impella Weaning Trial Process:

• Reduce Impella performance level (e.g., from P-8 to P-6 to P-4) while monitoring hemodynamics 1
• Assess hemodynamic parameters at each reduction: blood pressure, cardiac output, pulmonary capillary wedge pressure 1
• Perform serial echocardiography to evaluate left ventricular function during reduced support 1
• If hemodynamics remain stable at minimal support (P-2 or P-0) for several hours, proceed with device removal 1

Critical Considerations and Pitfalls

Complications to Monitor

Patients with ECPELLA configuration have higher rates of certain complications compared to ECMO alone:

• Hemolysis occurs at significantly higher rates (RR 1.70) with combined support 4
• Acute kidney injury requiring dialysis is more common (72% vs 18% in ECMO-only; RR 1.86) 3, 4
• Major bleeding and cerebrovascular accidents do not differ between ECPELLA and ECMO-only groups 4
• Limb ischemia, thrombosis, and bleeding remain concerns with Impella devices 1, 2

Oxygenation Considerations

In patients with severe lung injury, be aware of the "mixing zone" problem where deoxygenated blood from the Impella (antegrade flow) may compete with oxygenated blood from ECMO (retrograde flow). 7

• Monitor right radial artery oxygen saturation to detect inadequate coronary and cerebral oxygenation 7
• Consider veno-venous and arterial ECMO (V-VA ECMO) configuration if severe lung injury persists, allowing oxygenated blood return to both the inferior vena cava and femoral artery 7

Timing Considerations

Do not unnecessarily delay definitive therapy (durable LVAD or transplant) with prolonged attempts at optimization. 2

• 1 to 3 days is typically sufficient for initial hemodynamic optimization 2
• If improvements are not seen despite escalation, reconsider the patient's appropriateness for permanent support or proceed with surgical options 2

Outcomes

Concomitant Impella support during VA ECMO is associated with improved survival (RR 0.86 for mortality reduction) and significantly better ECMO weaning success. 3, 4

• All-cause mortality is significantly lower with ECPELLA (56% vs 82% in ECMO-only) 3
• Successful myocardial recovery and weaning from all mechanical support occurred in the majority of appropriate candidates (e.g., 5 of 8 adolescent patients in one series) 6
• Bridge to transplant or durable LVAD remains an option for those without adequate recovery 6, 5