1. Data to Delivery: The Evidence Base for VA-ECMO

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In this episode, CathMasters hosts Drs. Nazli Okumus and Daniel Ambinder, joined by expert faculty Drs. Ann Gage and Marwan Jumean, examine the foundational principles of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Utilizing a case study of a 36-year-old patient with fulminant myocarditis and biventricular failure, the panel analyzes the VA-ECMO circuit’s anatomy, clinical indications and contraindications, and the supporting evidence across various shock etiologies. The discussion also covers the debate over left ventricular (LV) unloading, the vital function of multidisciplinary shock teams, and strategies for informed consent and family counseling. This episode serves as an introduction to future discussions on cannulation techniques and complication management. Audio editing for this episode was performed by CardioNerds Intern, Dr. Julia Marques Fernandes. 

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Pearls

  1. “ECMO is an egotistical machine.” Inflow and outflow are referenced from the perspective of the ECMO circuit — inflow = blood entering the machine (venous/drainage cannula); outflow = blood leaving the machine (arterial/return cannula).
  2. VA-ECMO is the only temporary mechanical circulatory support (MCS) device that provides both full circulatory and respiratory support — making it uniquely suited for biventricular failure with concomitant hypoxemia, as in fulminant myocarditis.
  3. “VA-ECMO increases LV afterload” — but the hemodynamic story is more nuanced. The venous drainage cannula reduces right-sided preload, which may decrease LV filling and partially counterbalance the increase in afterload. Not every patient requires mechanical LV unloading; the loading conditions and contractility of both ventricles must be considered.
  4. Randomized controlled trial data for VA-ECMO in cardiogenic shock (ECLS-SHOCK, ECMO-CS) have been neutral. However, underlying diagnosis matters: survival is highest in fulminant myocarditis (~65%) and primary graft failure, and lowest in postcardiotomy shock (mortality ~65–75%).
  5. Shock teams improve outcomes. Multicenter data demonstrate that centers with shock teams have ~28% lower adjusted odds of cardiac ICU (CICU) mortality (adjusted OR 0.72), driven by earlier recognition, increased pulmonary artery catheter (PAC) use, and more appropriate deployment of MCS.

Notes

  1. Anatomy of the VA-ECMO Circuit
  • ECMO = Extracorporeal Membrane Oxygenation. VA-ECMO does the work of both the heart and the lungs — it provides full circulatory support and gas exchange, normalizing pCO2, pO2, and pH.
  • The circuit is the complete path blood travels from venous drainage to arterial return. Deoxygenated blood is drained via a large-bore venous cannula → centrifugal pump → membrane oxygenator (gas exchange) → oxygenated blood returned via a large-bore arterial cannula.
  • The two cannulas have three interchangeable naming conventions: Venous/Arterial, Inflow/Outflow (relative to the machine), or Drainage/Return (relative to the patient).
  • Peripheral VA-ECMO is placed percutaneously (Seldinger technique), often by an interventional cardiologist, surgeon, or critical care physician. The most common configuration is femoro-femoral: venous cannula tip at the SVC-RA junction, arterial cannula tip in the descending aorta. Alternatives include IJ venous/axillary arterial, or percutaneous left atrial VA-ECMO via transseptal cannulation (e.g., TandemHeart system or multi-stage cannula).
  • Central VA-ECMO requires surgical anastomosis to intrathoracic vessels; most commonly used in postcardiotomy patients.
  • A distal perfusion cannula (typically 5F–8F) is placed in the superficial femoral artery (SFA) to prevent limb ischemia.
  1. Indications and Contraindications for VA-ECMO
  • VA-ECMO is indicated for acute, potentially reversible cardiac or cardiopulmonary failure when conventional therapies have failed. It serves as a bridge to recovery, a bridge to decision, or a bridge to advanced therapies (durable VAD or heart transplant).
  • Indications:
    • Cardiogenic shock (CS): AMI, fulminant myocarditis, acute decompensated biventricular HF, postcardiotomy shock, cardiac transplant primary graft failure, arrhythmic storm, drug overdose/cardiotoxicity
    • Massive pulmonary embolism (PE): Bridge to thrombectomy or thrombolysis
    • Extracorporeal cardiopulmonary resuscitation (ECPR): Refractory cardiac arrest
    • Procedural support: High-risk PCI or structural procedures
  • Contraindications:
    • Relative: Contraindication to systemic anticoagulation, severe PAD limiting peripheral access (central cannulation may be considered), aortic dissection, significant aortic insufficiency
    • Absolute: Comfort-focused goals of care, irreversible neurological catastrophe, conditions incompatible with recovery, limited life expectancy (e.g., end-stage malignancy), established irreversible multi-organ failure
  1. Data for VA-ECMO Across Different Indications
  • The Extracorporeal Life Support Organization (ELSO) registry is the largest source of VA-ECMO outcomes data. Overall survival to hospital discharge for adult cardiac VA-ECMO is approximately 42% (Combes et al., Lancet 2020; 19,627 patients). Survival has remained relatively stable despite increasing utilization.
  • Survival varies significantly by underlying diagnosis (Danial et al., JACC 2023; Guglin et al., JACC 2019):
    • Fulminant myocarditis: ~65% survival (highest)
    • Primary graft failure after heart transplant: >50%
    • Drug overdose/cardiotoxicity: >50%
    • AMI-related CS: ~35–47%
    • Postcardiotomy shock: ~25–35% survival (poorest outcomes)
    • ECPR in adults: ~29.5% survival (ELSO 2022 report)
  • Pre-ECMO risk factors for poor outcomes: older age, higher BMI, renal/hepatic/CNS dysfunction, longer pre-ECMO mechanical ventilation, elevated lactate, reduced prothrombin activity, and pre-ECMO cardiac arrest.
  • The SAVE (Survival After Veno-Arterial ECMO) score is the most widely cited risk prediction tool, incorporating diagnosis, age, weight, organ function, and pre-ECMO intubation duration. AUROC 0.68 in derivation, 0.90 in external validation (Schmidt et al., Eur Heart J 2015).
  • Key RCT data:
    • ECLS-SHOCK (NEJM 2023): Largest RCT; AMI-CS patients randomized to early VA-ECMO vs. standard care. No difference in 30-day mortality (47.8% vs. 49.0%; RR 0.98; p=0.81). More bleeding/vascular complications with ECMO.
    • ECMO-CS (Circulation 2023): 117 patients with rapidly deteriorating/severe CS (multiple etiologies) randomized to immediate VA-ECMO vs. early conservative strategy. No difference in composite primary endpoint at 30 days (63.8% vs. 71.2%; HR 0.72; p=0.21). Post-hoc analyses suggest potential benefit in patients with CI <2.2 L/min/m², SvO2 <60%, or elevated pCO2 gap (Ostadal et al., Crit Care 2025).
    • IPD meta-analysis of four RCTs (Zeymer et al., Lancet 2023): No mortality benefit with routine VA-ECMO in AMI-CS; more complications in the device group.
  • ECPR data:
    • ARREST (Lancet 2020): Refractory OHCA with VF; stopped early for superiority — 43% vs. 7% survival to discharge.
    • Prague OHCA (JAMA 2022): Shockable and non-shockable rhythms; 180-day neurologically favorable survival 31.5% vs. 22.0% (p=0.09); 30-day neurologic recovery significantly better (30.6% vs. 18.2%; p=0.02).
    • INCEPTION (NEJM 2023): Multicenter; refractory OHCA with ventricular arrhythmias; 30-day favorable neurologic outcome 20% vs. 16% (OR 1.4; p=0.52). Longer cannulation times and lower-volume centers may have contributed to neutral results.
    • Pooled analysis of ARREST + Prague OHCA (Belohlavek et al., EClinicalMedicine 2023): Significant benefit for ECPR in shockable rhythms — 47.1% vs. 28.3% neurologically favorable survival at 180 days (NNT = 5).
    • The 2023 AHA Focused Update on Adult ACLS (Circulation 2024) gives a Class 2b (conditional) recommendation for ECPR in select patients with refractory OHCA at experienced, high-volume centers.
  1. LV Unloading on VA-ECMO
  • VA-ECMO increases LV afterload via retrograde aortic flow. The concern: increased afterload → elevated LVEDP/volume → increased myocardial O2 demand → worsened LV function → pulmonary congestion and LV stasis.
  • The nuance: The venous drainage cannula directly drains the right heart, reducing RA preload and RV stroke volume. On the ascending limb of the Frank-Starling curve, decreased RV preload → less LV filling, partially counterbalancing the afterload increase. The hemodynamic response depends on loading conditions and contractility of both ventricles (University of Minnesota group, in vivo data).
  • LV unloading strategies: IABP (reduces afterload, improves coronary perfusion), micro-axial flow pump/Impella (directly unloads LV), transseptal LA cannulation, atrial septostomy, surgical LV apical drainage.
  • Observational data (Schrage et al., Circulation 2020): LV unloading associated with lower mortality in a multicenter cohort.
  • RCTs have not confirmed the benefit of routine unloading:
    • EARLY-UNLOAD (Circulation 2023): Early LV unloading vs. conventional approach — no mortality difference (46.6% vs. 44.8%; p=0.94).
    • EVOLVE-ECMO (Eur J Heart Fail 2023): Early LA venting vs. conventional — no difference in ECMO weaning or survival.
  • Practical consideration: Many operators deploy upfront unloading because the patient is already in the cath lab, avoiding repeated transport on ECMO. The decision should also factor in the goal of ECMO (LV recovery vs. bridge to replacement therapy).
  1. The Role of the Shock Team
  • Shock teams are multidisciplinary groups (interventional cardiology, heart failure/transplant, cardiac surgery, critical care, and anesthesiology) that facilitate early recognition, evaluation, and management of CS.
  • Multicenter data (Papolos et al., JACC 2021; >1,200 CS admissions): Centers with shock teams had ~28% lower adjusted odds of CICU mortality (adjusted OR 0.72; 95% CI 0.55–0.95; p=0.019).
  • Mechanisms of benefit: earlier identification before multi-organ dysfunction, increased PAC use for hemodynamic phenotyping, more appropriate/timely MCS deployment, streamlined care delivery.
  • The 2025 ACC Expert Consensus Statement on Cardiogenic Shock (Sinha et al., JACC 2025) strongly recommends a standardized, interdisciplinary, team-based approach and early contact with regional Level 1 CS centers.
  1. Consent for VA-ECMO: Risks, Benefits, Alternatives
  • Consent is frequently obtained from a surrogate (POA/next of kin) because patients are often too ill to participate.
  • Key elements:
    • Simple description: VA-ECMO is full life support that does the work of the heart and lungs for days to weeks.
    • Indication: Support the heart and maintain organ function while treating the underlying cause.
    • Procedure: Large cannulas placed in the groin vessels, connected to an external machine.
    • Risks: Life-threatening bleeding, stroke, limb ischemia, infection. Overall survival <50%, though individual prognosis varies by underlying condition.
    • Benefits: Time for the heart to recover, for additional treatments, and for organ preservation. If no recovery, may bridge to durable VAD or transplant.
    • Alternatives: Continued medical therapy with vasoactive medications.
    • Expectations: Period of attempted stabilization → best case: recovery. If not, ECMO maintained days to weeks while evaluating advanced therapies. Typical course: 1–3 weeks in cardiac ICU, potentially extended rehabilitation.
  • Understanding the patient’s premorbid condition and wishes is imperative. An ECMO coordinator can serve as an early information gatherer, contacting the POA to learn about baseline condition and preferences before the physician seeks formal consent.
  • Discontinuation should be discussed upfront. The “bridge to nowhere” scenario raises profound ethical challenges; early palliative care and ethics consultation involvement is recommended.

References

  1. ★ Combes A, Price S, Slutsky AS, Brodie D. Temporary circulatory support for cardiogenic shock. Lancet. 2020;396(10245):199-212. doi:10.1016/S0140-6736(20)31047-3
  2. ★ Tonna JE, Boonstra PS, MacLaren G, et al. Extracorporeal Life Support Organization Registry International Report 2022: 100,000 survivors. ASAIO J. 2024;70(2):131-143. doi:10.1097/MAT.0000000000002128
  3. ★ Thiele H, Zeymer U, Akin I, et al. Extracorporeal life support in infarct-related cardiogenic shock. N Engl J Med. 2023;389(14):1286-1297. doi:10.1056/NEJMoa2307227
  4. ★ Ostadal P, Rokyta R, Karasek J, et al. Extracorporeal membrane oxygenation in the therapy of cardiogenic shock: results of the ECMO-CS randomized clinical trial. Circulation. 2023;147(6):454-464. doi:10.1161/CIRCULATIONAHA.122.062949
  5. Ostadal P, Rokyta R, Karasek J, et al. Extracorporeal membrane oxygenation in the therapy of cardiogenic shock: 1-year outcomes of the ECMO-CS trial. Eur J Heart Fail. 2025;27(1):30-36. doi:10.1002/ejhf.3398
  6. Ostadal P, Vondrakova D, Rokyta R, et al. Cardiac index, SvO2 or pCO2 gap may determine benefit from ECMO in cardiogenic shock: post-hoc analysis of the ECMO-CS trial. Crit Care. 2025;29(1):303. doi:10.1186/s13054-025-05513-5
  7. ★ Zeymer U, Freund A, Hochadel M, et al. Venoarterial extracorporeal membrane oxygenation in patients with infarct-related cardiogenic shock: an individual patient data meta-analysis of randomised trials. Lancet. 2023;402(10410):1338-1346. doi:10.1016/S0140-6736(23)01607-0
  8. ★ Yannopoulos D, Bartos J, Raveendran G, et al. Advanced reperfusion strategies for patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (ARREST). Lancet. 2020;396(10265):1807-1816. doi:10.1016/S0140-6736(20)32338-2
  9. ★ Belohlavek J, Smalcova J, Rob D, et al. Effect of intra-arrest transport, extracorporeal cardiopulmonary resuscitation, and immediate invasive assessment and treatment on functional neurologic outcome in refractory out-of-hospital cardiac arrest (Prague OHCA). JAMA. 2022;327(8):737-747. doi:10.1001/jama.2022.1025
  10. ★ Suverein MM, Delnoij TSR, Lorusso R, et al. Early extracorporeal CPR for refractory out-of-hospital cardiac arrest (INCEPTION). N Engl J Med. 2023;388(4):299-309. doi:10.1056/NEJMoa2204511
  11. Belohlavek J, Yannopoulos D, Smalcova J, et al. Intraarrest transport, extracorporeal cardiopulmonary resuscitation, and early invasive management in refractory out-of-hospital cardiac arrest: an individual patient data pooled analysis of two randomised trials. EClinicalMedicine. 2023;59:101988. doi:10.1016/j.eclinm.2023.101988
  12. Supady A, Bělohlávek J, Combes A, et al. Extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest. Lancet Respir Med. 2025;13(9):843-856. doi:10.1016/S2213-2600(25)00122-5
  13. ★ Schmidt M, Burrell A, Roberts L, et al. Predicting survival after ECMO for refractory cardiogenic shock: the Survival After Veno-Arterial-ECMO (SAVE)-score. Eur Heart J. 2015;36(33):2246-2256. doi:10.1093/eurheartj/ehv194
  14. ★ Danial P, Olivier ME, Bréchot N, et al. Association between shock etiology and 5-year outcomes after venoarterial extracorporeal membrane oxygenation. J Am Coll Cardiol. 2023;81(9):897-909. doi:10.1016/j.jacc.2022.12.018
  15. ★ Guglin M, Zucker MJ, Bazan VM, et al. Venoarterial ECMO for adults: JACC Scientific Expert Panel. J Am Coll Cardiol. 2019;73(6):698-716. doi:10.1016/j.jacc.2018.11.038
  16. ★ Papolos AI, Kenigsberg BB, Berg DD, et al. Management and outcomes of cardiogenic shock in cardiac ICUs with versus without shock teams. J Am Coll Cardiol. 2021;78(13):1309-1317. doi:10.1016/j.jacc.2021.07.044
  17. ★ Sinha SS, Morrow DA, Kapur NK, Kataria R, Roswell RO. 2025 Concise clinical guidance: an ACC expert consensus statement on the evaluation and management of cardiogenic shock. J Am Coll Cardiol. 2025;85(16):1618-1641. doi:10.1016/j.jacc.2025.02.018
  18. ★ Schrage B, Becher PM, Bernhardt A, et al. Left ventricular unloading is associated with lower mortality in patients with cardiogenic shock treated with venoarterial extracorporeal membrane oxygenation. Circulation. 2020;142(22):2095-2106. doi:10.1161/CIRCULATIONAHA.120.048792
  19. Kim MC, Lim Y, Lee SH, et al. Early left ventricular unloading or conventional approach after venoarterial extracorporeal membrane oxygenation: the EARLY-UNLOAD randomized clinical trial. Circulation. 2023;148(20):1570-1581. doi:10.1161/CIRCULATIONAHA.123.066179
  20. Park H, Yang JH, Ahn JM, et al. Early left atrial venting versus conventional treatment for left ventricular decompression during venoarterial extracorporeal membrane oxygenation support: the EVOLVE-ECMO randomized clinical trial. Eur J Heart Fail. 2023;25(11):2037-2046. doi:10.1002/ejhf.3014
  21. Russo JJ, Aleksova N, Pitcher I, et al. Left ventricular unloading during extracorporeal membrane oxygenation in patients with cardiogenic shock. J Am Coll Cardiol. 2019;73(6):654-662. doi:10.1016/j.jacc.2018.10.085
  22. Perman SM, Elmer J, Maciel CB, et al. 2023 American Heart Association focused update on adult advanced cardiovascular life support. Circulation. 2024;149(5):e254-e273. doi:10.1161/CIR.0000000000001194
  23. Thiele H, Hassager C. Cardiogenic shock. N Engl J Med. 2026;394(1):62-77. doi:10.1056/NEJMra2312086
  24. Lüsebrink E, Binzenhöfer L, Adamo M, et al. Cardiogenic shock. Lancet. 2024;404(10466):2006-2020. doi:10.1016/S0140-6736(24)01818-X
  25. Enumah ZO, Carrese J, Choi CW. The ethics of extracorporeal membrane oxygenation: revisiting the principles of clinical bioethics. Ann Thorac Surg. 2021;112(1):61-66. doi:10.1016/j.athoracsur.2020.08.045
  26. Bernhardt AM, Copeland H, Deswal A, Gluck J, Givertz MM. The International Society for Heart and Lung Transplantation/Heart Failure Society of America guideline on acute mechanical circulatory support. J Card Fail. 2023;29(3):304-374. doi:10.1016/j.cardfail.2022.11.003