Steps of Transcatheter Aortic Valve Implantation (TAVI)
TAVI is performed through a systematic sequence involving patient preparation, vascular access establishment, valve positioning under rapid pacing, deployment, and post-deployment assessment, with the specific procedural steps varying based on the chosen access route (transfemoral, transapical, transaortic, or transsubclavian). 1, 2
Pre-Procedural Preparation
Before entering the procedural suite, several critical steps must be completed:
- Vascular access planning: Place femoral arterial and venous access wires for hemodynamic monitoring and temporary pacing 3
- Anesthesia: General anesthesia capability must be available, though conscious sedation may be used in selected cases 2
- Imaging setup: Position fixed fluoroscopy equipment and ensure transesophageal echocardiography (TEE) or intracardiac echo is ready for real-time guidance 2, 4
- Temporary pacing: Establish ventricular pacing capability, typically through femoral venous access with pacing wire positioned in right ventricle 3
Access Route Selection and Establishment
The procedure diverges based on the chosen access route 4, 5:
Transfemoral Approach (Retrograde)
- Percutaneous access to femoral artery (requires vessel diameter ≥6-9 mm depending on device) 1
- Advance large-bore sheath retrograde through iliac vessels and descending aorta
- Navigate aortic arch to reach ascending aorta 4
Transapical Approach (Antegrade)
- Perform anterolateral mini-thoracotomy (typically 5th or 6th intercostal space) 6, 3
- Expose left ventricular apex
- Place epicardial pacing wires directly on heart 3
- Create apical pursestring suture for valve delivery system insertion 6, 3
- Puncture apex and introduce delivery system antegrade across native aortic valve 6
Transaortic Approach
- Upper mini-sternotomy or right anterior thoracotomy 7
- Direct puncture of ascending aorta
- Antegrade access to aortic valve 7
Transsubclavian Approach
- Access via left subclavian artery (most common) 4
- Retrograde passage similar to transfemoral but through upper extremity vasculature 4
Crossing the Native Valve
- Advance guidewire across stenotic native aortic valve under fluoroscopic guidance 4
- Position stiff guidewire in left ventricle (for retrograde approaches) or ascending aorta (for antegrade approaches)
- This wire serves as the rail for all subsequent equipment 4
Balloon Aortic Valvuloplasty (BAV)
- Advance valvuloplasty balloon across native valve over guidewire 1
- Initiate rapid ventricular pacing (typically 180-220 beats per minute) to reduce cardiac output and stabilize balloon position 3
- Inflate balloon to pre-dilate stenotic valve and assess:
- Deflate balloon and remove while maintaining wire position
Valve Positioning
This is the most critical phase requiring precise technique:
- Load and advance prosthesis: Crimped valve on delivery catheter advanced over guidewire to aortic annulus 4
- Positioning under dual guidance: Use both fluoroscopy and echocardiography (TEE) to align valve 2, 3
- Fluoroscopic landmarks: Calcification of native leaflets, coronary ostia
- Echo confirmation: Valve position relative to annulus and left ventricular outflow tract
- Rapid pacing: Reinitiate rapid ventricular pacing to reduce cardiac motion and prevent valve migration during deployment 3
Valve Deployment
Technique differs by valve type:
Balloon-Expandable Valves
- Inflate deployment balloon during rapid pacing 4
- Valve expands to predetermined size based on balloon inflation
- Immediate fixation upon full expansion
- Deflate balloon and remove delivery system
Self-Expanding Valves
- Gradually unsheath valve frame 4
- Nitinol frame expands to body temperature, conforming to annulus 8
- Allows repositioning before full deployment in some systems
- Complete unsheathing for final deployment
Immediate Post-Deployment Assessment
- Cease rapid pacing and allow heart to resume normal rhythm
- Hemodynamic evaluation: Measure transvalvular gradients via catheter pullback
- Echocardiographic assessment 2:
- Valve position and stability
- Paravalvular regurgitation severity and location
- Coronary flow (ensure no ostial obstruction)
- Left ventricular function
- New wall motion abnormalities
- Aortography: Assess for aortic regurgitation and vascular complications 1
Access Site Closure
- Transfemoral: Percutaneous closure devices or surgical repair of arteriotomy
- Transapical: Secure apical pursestring sutures, close thoracotomy in layers 6, 3
- Transaortic/transsubclavian: Direct surgical repair of arteriotomy 7
Critical Procedural Considerations
Common pitfalls to avoid:
- Valve migration: Occurs with undersizing or inadequate anchoring—prevented by accurate annular measurement (TEE preferred over TTE as it shows larger values) 1
- Coronary obstruction: Risk highest with asymmetric heavy calcification—assess during BAV and maintain high index of suspicion 1
- Paravalvular leak: Minimized by correct sizing and use of devices with pericardial skirts 8
- Conduction abnormalities: High risk of AV block requiring permanent pacemaker, particularly with self-expanding valves 1
- Vascular complications: More common with transfemoral approach—careful pre-procedural CT assessment of iliofemoral vessels mandatory 1, 2
- Stroke: Risk elevated with transfemoral approach due to arch manipulation—embolic protection devices may be considered 1
Equipment requirements 2:
- Cardiopulmonary bypass capability must be immediately available for emergency conversion
- Peripheral and coronary intervention equipment on standby for complication management
- High-quality fixed imaging with capability for multiple angulations
- Hybrid operating room or specially modified large catheterization laboratory preferred 1, 2
The procedure requires a multidisciplinary heart team including interventional cardiologists, cardiac surgeons, imaging specialists, and cardiac anesthesiologists present throughout 1, 2. The entire team must be experienced in structural heart disease, with surgical backup immediately available for conversion to open surgery if complications arise 2.