The goal of this clinical trial is to evaluate the feasibility, effectiveness, and safety of pre-emptive left atrial veno-arterial extracorporeal membrane oxygenation (LAVA-ECMO) in patients undergoing complex and high-risk transcatheter aortic valve replacement (TAVR). These patients include adults with severe aortic stenosis who are hemodynamically unstable or at risk of instability due to anatomical complexity. The main questions it aims to answer are:

1. Does pre-emptive LAVA-ECMO reduce the incidence of in-hospital death, intraprocedural cardiac arrest, or emergent cardiac surgery?
2. What are the safety outcomes related to LAVA-ECMO, including major vascular, bleeding, or cardiac structural complications? -This is a single-arm, prospective, multi-center study with no comparison group.

Participants will:

• Be screened for eligibility based on hemodynamic status and anatomical complexity
• Undergo pre-emptive LAVA-ECMO cannulation prior to or during TAVR
• Receive follow-up assessments at 30 days and 1 year, including clinical evaluation and echocardiography

Inclusion Criteria:

- Patients are required to have either a Class III hemodynamic status OR type B or type C anatomical complexity with Class II (at risk) hemodynamics (Figure 2).

• Hemodynamic Criteria

  • Major Criteria (Class III)

    • Systolic blood pressure <90 mmHg or MAP<60 mmHg
    • Need for vasopressors or inotropes to maintain MAP>60 mmHg
    • Evidence of end-organ damage including: acute kidney injury, liver dysfunction, elevated lactate or altered mentation

  • Minor Criteria (Class II)

    • Left ventricular ejection fraction <35%
    • Pulmonary hypertension (pulmonary artery systolic pressure >60 mmHg) with right ventricular dysfunction
    • Pulmonary capillary wedge pressure >30 mmHg

• Anatomic criteria

  • Major Criteria (Type C)

    • Native or valve-in-valve TAVR requiring single-leaflet modification for a large area of myocardium at risk (e.g. patients with large or dominant left circulation)
    • Native or valve-in-valve TAVR requiring dual-leaflet modification
    • Severe bioprosthetic aortic regurgitation
    • Severe 3-vessel coronary artery disease not amenable to revascularization (SYNTAX score >33)

  • Minor Criteria (Type B)

    • Native or valve-in-valve TAVR requiring single-leaflet modification
    • Severe commissural misalignment requiring leaflet modification
    • High-risk for coronary occlusion not amenable to leaflet modification
    • Critical low-flow low-gradient aortic stenosis (defined as an estimated aortic valve area ≤0.5 cm2)

Exclusion Criteria:

• Age <18 or pregnant

  • General absolute contraindications to TAVR
  • Severe peripheral artery disease with infeasibility for veno-arterial extracorporeal membrane oxygenation implantation.
  • Contraindications to transeptal cannulation (e.g. pre-existing interatrial septum occluder device).
  • Pre-existing Impella treatment.
  • Onset of shock >12 hours.
  • Preceding cardiac arrest with prolonged resuscitation (>40 minutes).
  • Other severe concomitant disease with life expectancy <6 months.
  • Participation in another trial with an intervention.
  • Any class I hemodynamic status
  • Type A anatomical complexity with class I or II hemodynamic status

Study participants will be recruited from Atlantic Health System hospitals and affiliated centers. Eligible individuals are adult patients diagnosed with severe native aortic stenosis or degenerated bioprosthetic aortic valves who are scheduled for transcatheter aortic valve replacement (TAVR). Patients are identified through institutional clinical practices and referrals, including those admitted to the cardiac care unit with signs of hemodynamic instability or anatomical complexity. Recruitment may include critically ill patients who are sedated or intubated, with consent obtained from legally authorized representatives when necessary.