2. Proctor’s Playbook: VA-ECMO

CathMasters Drs. Nazli Okumus and Daniel Ambinder, along with expert faculty Drs. Ann Gage and Marwan Jumean, walk through the step-by-step procedural approach to VA-ECMO (veno-arterial extracorporeal membrane oxygenation) cannulation. Building on the Data to Delivery episode, this Proctor Playbook episode covers pre-procedural planning, cannula selection, team composition and equipment, the role of the distal perfusion cannula (DPC), decision-making on mechanical left ventricular (LV) unloading, anticoagulation dosing and timing, the cannulation procedure itself, and vascular closure strategies during decannulation. The hypothetical case continues with the 36-year-old man with fulminant myocarditis, biventricular failure, and cardiogenic shock. Audio editing for this episode was performed by CardioNerds Intern, Dr. Julia Marques Fernandes. CathMasters is for educational purposes only. CathMasters is for educational purposes only. Music by Elijah K from Pixabay Pearls "Cannulation for VA-ECMO is a team sport." Success begins with pre-procedural planning: review the patient's history, prior vascular imaging, echocardiography, invasive hemodynamics, labs, and EKG to phenotype the shock (left, right, or biventricular) and select the appropriate support configuration and cannula sizes. The distal perfusion cannula (DPC) should be the standard of care. Meta-analyses demonstrate that prophylactic DPC placement reduces limb ischemia by ~60% (OR 0.31–0.41). A practical tip from Dr. Gage: perform the antegrade SFA stick for the DPC simultaneously with the retrograde CFA stick before upsizing — this avoids the difficulty of obtaining antegrade access after a large arterial cannula is already in place. Heparin dosing at cannulation: administer an initial bolus of 50–100 U/kg of unfractionated heparin (UFH) after access but before dilation. For a 70 kg patient, this is approximately 5,000 units. Maintain anticoagulation with a UFH infusion targeting ACT 180–220 seconds, aPTT 1.5–2.5× baseline, or anti-Xa 0.3–0.7 IU/mL. Consider upsizing the dilator 1–2 French above the intended cannula size (e.g., dilate to 27F for a 25F venous cannula) to facilitate smooth cannula insertion. Dr. Jumean’s pro tip: after removing the dilator, check wire movement before advancing the cannula — a kinked wire during dilation is a preventable but dangerous complication. Percutaneous decannulation is an evolving and viable alternative to surgical cutdown. Pre-closing at the time of cannulation (two Perclose ProGlide devices per site) enables percutaneous explantation with technical success rates of 91–95% and lower groin infection rates compared with surgical cutdown. Notes Pre-Procedural Planning VA-ECMO cannulation requires significant pre-planning and coordination, even when time is limited. The operator should review all primary data with the team before proceeding. Key data to review: Echocardiography: Biventricular function, valvular disease (especially aortic insufficiency and mitral regurgitation), wall motion abnormalities, and chamber sizes. Echo also helps refine the differential diagnosis (e.g., regional wall motion abnormalities suggest CAD; flail mitral leaflet suggests delayed MI complication). Invasive hemodynamics (PA catheter): Phenotype the shock as left-dominant, right-dominant, or biventricular. This determines the support configuration (VA-ECMO alone vs. VA-ECMO + LV unloading vs. VAV-ECMO for additional oxygenation). Prior vascular imaging: Review prior angiograms or CT scans of the femoral/iliac vessels to assess vessel size, tortuosity, calcification, and PAD. This informs cannula sizing and access strategy. EKG and labs: Confirm diagnosis, assess for arrhythmias, and evaluate organ function (renal, hepatic, coagulation). Dr. Gage’s program uses a formal ECMO timeout before cannulation — a checklist that reviews indications, contraindications, equipment, and team roles. Equipment and Team Team composition: Cannulating operator (interventional cardiologist, cardiac surgeon, or critical care physician), assistant (fellow or second operator), perfusionist (to prime and manage the circuit), ICU or cath lab nurse, and a cardiac surgeon aware and available as backup. The equipment cart should include: Vascular access kit with micropuncture needles and sheaths A stiff guidewire Sequential dilators Venous cannula: 23–25F multi-stage (most common); 21F may be used in smaller patients. Flow through the circuit is primarily determined by the venous drainage cannula size. Arterial cannula: 15–20F single-stage, selected based on patient body size and vessel diameter. There is a trend toward smaller arterial cannulas (15–17F) to minimize bleeding and ischemic complications and facilitate percutaneous removal. The vessel should ideally be 1–2 mm larger than the cannula to reduce limb ischemia risk. Distal perfusion cannula: 5–8F antegrade sheath for the SFA or retrograde via the posterior tibial artery Surgical cutdown kit (backup) Ultrasound for vascular access guidance Pre-close devices (Perclose ProGlide) if percutaneous decannulation is planned ECMO cannulations may occur in the cath lab, ICU, emergency department, or in the field. Having a mobile ECMO cart with all equipment pre-assembled allows rapid deployment to any location. Distal Perfusion Cannula (DPC) The DPC should be considered standard of care for all patients receiving femoral VA-ECMO. Limb ischemia historically occurred in ~17% of peripheral VA-ECMO patients, with 10% requiring fasciotomy and ~5% requiring amputation. A meta-analysis by Juo et al. (2017) demonstrated that prophylactic DPC placement reduced the incidence of limb ischemia from 25.4% to 9.7% (RR, 0.41; 95% CI, 0.26–0.65). A subsequent meta-analysis by Marbach et al. (2022) confirmed this finding (OR 0.31; 95% CI 0.21–0.47; p<0.001). A multicenter registry study (Lee et al., 2023) further showed that prophylactic DPC was associated with lower 30-day mortality (33.1% vs. 53.2%; RR 0.68). Technique: A 6–8F antegrade sheath is placed in the ipsilateral SFA and connected to the arterial limb of the ECMO circuit via a Y-connector (using a male-to-male connection), diverting a portion of oxygenated blood to the distal limb. Dr. Gage's tip: Perform the antegrade SFA stick at the same time as the retrograde CFA stick, before any cannulas are placed. Using ultrasound, obtain retrograde CFA access with the right hand, leave the micropuncture wire, then quickly scan distally to the SFA and obtain antegrade access with the left hand. Place 6F sheaths over both wires. This provides the best ultrasound view (no large cannula obstructing), preserves SFA flow for the antegrade stick. Exception: do not do this during active ECPR — proceed directly to cannulation and obtain the DPC later once the patient is stabilized. Monitoring: Hourly Doppler checks of distal pulses, near-infrared spectroscopy (NIRS) of the cannulated vs. non-cannulated leg, and clinical assessment (pallor, temperature, capillary refill). Elevated CPK or lactate are late and concerning findings. Decision-Making on Mechanical LV Unloading VA-ECMO increases LV afterload via retrograde aortic flow. The decision to add an unloading device depends on the underlying etiology, expected recovery timeframe, and real-time hemodynamic assessment. Key assessment parameters: Arterial pulsatility: A pulse pressure ≥20 mmHg suggests some native cardiac output and aortic valve opening. If pulsatility is absent or minimal, LV distension and stasis are more likely. Echocardiographic assessment: Aortic valve opening with each cardiac cycle, LV cavity size, presence of spontaneous echo contrast or thrombus, and degree of mitral regurgitation. In practice, most patients do not meet the 20 mmHg pulse pressure threshold immediately after cannulation, so many operators deploy an upfront unloading strategy (IABP or Impella) when the patient is already in the cath lab — avoiding the need for repeated transport on ECMO. The goal of ECMO support also matters: if the goal is LV recovery (e.g., myocarditis), aggressive unloading to rest the myocardium may be more important than if the goal is bridge to transplant or durable VAD. Unloading options: IABP (reduces afterload, improves coronary perfusion), Impella (directly unloads LV), transseptal LA cannulation, or atrial septostomy. Anticoagulation Unfractionated heparin (UFH) is the standard anticoagulant for VA-ECMO. The ELSO guidelines (2017) and ISHLT/HFSA guideline (2023) recommend an initial bolus of 50–100 U/kg at the time of cannulation. Timing: Administer heparin after vascular access is obtained but before dilation and cannula insertion. In the episode, Dr. Gage's protocol uses 70 U/kg (e.g., 70 kg × 70 U/kg = ~5,000 U). Maintenance anticoagulation targets (significant institutional variability exists): ACT: 180–220 seconds (ELSO recommendation) aPTT: 1.5–2.5× baseline (approximately 50–75 seconds) Anti-Xa: 0.3–0.7 IU/mL Alternatives for heparin-induced thrombocytopenia (HIT): Bivalirudin or argatroban, monitored by aPTT 50–60 seconds. The balance between thrombotic and hemorrhagic complications is critical. The ECMO circuit's nonendothelial surface triggers an inflammatory and prothrombotic response with consumptive coagulopathy, while simultaneously causing platelet dysfunction and von Willebrand factor proteolysis, creating a pro-hemorrhagic phenotype. Cannulation Procedure: Step-by-Step Step 1 — Access: Using ultrasound guidance, obtain femoral arterial and venous access with micropuncture needles. Ultrasound-guided access is strongly preferred to reduce vascular complications, though in emergencies (ECPR) it may not always be feasible. Step 2 — Wire exchange: Exchange the micropuncture wire for a supportive guidewire through the micropun