What are the criteria for a successful Transcatheter Aortic Valve Implantation (TAVI) procedure?

Criteria for Successful TAVI

A successful TAVI procedure requires meeting four critical domains: appropriate patient selection with confirmed severe symptomatic aortic stenosis, anatomically suitable valve and vascular dimensions, absence of absolute contraindications, and achievement of procedural success defined by proper valve deployment with minimal paravalvular regurgitation.

Patient Selection Criteria

Disease Severity Confirmation

• Severe aortic stenosis must be documented by echocardiography using combined measurements of valve area and flow-dependent indices 1
• Low-dose dobutamine echocardiography should be performed in patients with low LV ejection fraction and low gradient to differentiate true severe stenosis from pseudo-severe stenosis 1
• Only symptomatic patients should undergo TAVI due to ongoing questions about safety and valve durability 1

Risk Assessment

• High surgical risk is defined by logistic EuroSCORE ≥15-20% or STS mortality risk score ≥10% 2
• Risk scores (EuroScore, STS, Ambler) provide guidance but have reduced predictive ability in this heterogeneous high-risk population 1
• Patient characteristics favoring TAVI include prior cardiac surgery with grafts/adhesions, previous chest radiation, porcelain aorta, liver cirrhosis, pulmonary hypertension, right ventricular failure, and marked frailty 2

Anatomical Feasibility Requirements

Aortic Annulus Sizing

• Correct valve sizing is critical to minimize paravalvular leakage and prevent prosthesis migration 1
• Acceptable annulus dimensions: 18-25 mm for balloon-expandable devices and 20-27 mm for self-expandable devices 1
• TEE should be performed when borderline values create doubt, as it shows larger values than transthoracic echocardiography 1
• Multislice CT or MRI can supplement measurements; aortography during balloon aortic valvuloplasty is also useful 1

Aortic Root Assessment

• Aortic root dimension must be ≥45 mm at the aorto-tubular junction for self-expandable prostheses 1
• Echocardiography is the preferred tool for assessing LV outflow tract morphology and aortic root dimensions 1

Vascular Access Evaluation

• Angiography is the reference standard for evaluating peripheral artery size, tortuosity, and calcification 1
• Multislice CT can also be used; MRI is helpful in patients with renal insufficiency 1

Absolute Contraindications

General Contraindications

• Bicuspid valves (risk of incomplete prosthesis deployment) 1
• Asymmetric heavy valvular calcification that may compress coronary arteries during TAVI 1
• Presence of apical LV thrombus 1
• Life expectancy <1 year 2
• Unlikely improvement in quality of life due to comorbidities 2
• Active endocarditis 2
• Severe primary disease of other valves requiring surgical treatment 2

Coronary Considerations

• Coronary angiography must be performed to assess coronary anatomy 1
• TAVI is probably not recommended in patients with severe proximal coronary stenoses not amenable to percutaneous coronary intervention 1
• The risk of coronary compression can be anticipated during balloon aortic valvuloplasty 1

Transfemoral Approach Contraindications

• Iliac arteries with severe calcification, tortuosity, diameter <6-9 mm (device-dependent), or previous aorto-femoral bypass 1
• Severe aortic angulation, severe atheroma of the arch, coarctation, or abdominal aortic aneurysm with protruding mural thrombus 1
• Bulky atherosclerosis of ascending aorta and arch detected by TEE 1
• Transverse ascending aorta (for balloon-expandable devices) 1

Transapical Approach Contraindications

• Previous LV surgery using a patch (e.g., Dor procedure) 1
• Calcified pericardium 1
• Severe respiratory insufficiency 1
• Non-reachable LV apex 1

Procedural Success Criteria

Technical Success Markers

• Procedural success rates reach approximately 93.8% in experienced centers with proper patient selection 2
• Successful valve implantation is achieved in 96% of appropriately selected patients 3
• Final valve area should be 1.5-1.8 cm², representing effective resolution of valvular obstruction 4
• Post-procedural mean transvalvular gradient should be significantly reduced (typically to <25 mm Hg) 5, 3

Acceptable Complications Profile

• Paravalvular regurgitation occurs in 50% of cases, but severe regurgitation (>grade 3) should be <5% with proper sizing 4
• 30-day mortality should be 0-6.3% for transfemoral approach 2
• Vascular complications occur in 10-15% with transfemoral approach 2, 4
• Stroke risk is 3-9% 2, 4
• Atrioventricular block requiring pacemaker occurs in 4-8% (up to 24% with self-expandable devices) 2, 4

Common Pitfalls to Avoid

• Undersizing or oversizing the valve leads to paravalvular leaks or coronary obstruction—use multiple imaging modalities for accurate annulus measurement 1
• Proceeding with TAVI in patients with bicuspid valves risks incomplete deployment 1
• Ignoring severe coronary disease that cannot be revascularized percutaneously increases procedural risk 1
• Inadequate assessment of peripheral vascular anatomy leads to access site complications 1
• Treating patients with life expectancy <1 year or those unlikely to benefit from quality of life improvement wastes resources and exposes patients to unnecessary risk 2