Is the Accura balloon (Balloon Mitral Valvuloplasty (BMV)) a suitable treatment option for a patient with mitral stenosis?

Accura Balloon for Balloon Mitral Valvuloplasty (BMV)

Balloon mitral valvuloplasty is the first-line treatment for symptomatic patients with moderate to severe rheumatic mitral stenosis who have favorable valve morphology (thickened leaflets with fused commissures), and it is equally indicated for asymptomatic patients with pulmonary hypertension. 1

When BMV is Definitively Indicated

Class I indications for balloon valvuloplasty include:

• Symptomatic patients (NYHA class II-IV) with moderate to severe rheumatic mitral stenosis (mitral valve area ≤1.5 cm²) who have favorable valve morphology, specifically thickened leaflets with fused commissures, in the absence of left atrial thrombus or moderate to severe mitral regurgitation 1

• Asymptomatic patients with moderate to severe rheumatic mitral stenosis who have pulmonary hypertension (pulmonary artery systolic pressure >50 mm Hg at rest or >60 mm Hg with exercise) and favorable valve morphology, without left atrial thrombus or significant mitral regurgitation 1

• Patients with rheumatic mitral valve restenosis after previous intervention who meet the above criteria 1

• Children >5 years of age with symptomatic congenital mitral stenosis or restenosis who have favorable mitral valve morphology (thickened leaflets and fused commissure) 2

Defining Favorable Valve Morphology

Favorable anatomy for balloon valvuloplasty includes commissural fusion with relatively pliable leaflets, balanced chordal attachments, and minimal calcification, as assessed by the Wilkins echocardiographic score. 1 The presence of highly calcified and fibrotic mitral valve leaflets increases procedural risks and yields suboptimal results. 3

Absolute Contraindications

• Left atrial thrombus (must be excluded by transesophageal echocardiography) 1
• Moderate to severe mitral regurgitation at baseline 1
• Mild mitral stenosis (mitral valve area >1.5 cm²) without hemodynamically significant features 1

Clinical Algorithm for Decision-Making

The American College of Cardiology recommends a stepwise approach:

1. Confirm rheumatic etiology of mitral stenosis 1
2. Assess severity (mitral valve area ≤1.5 cm²) 1
3. Evaluate symptoms (NYHA class) or measure pulmonary artery pressures in asymptomatic patients 1
4. Perform transesophageal echocardiography to exclude left atrial thrombus 1
5. Calculate Wilkins score to assess valve morphology 1
6. Exclude moderate-severe mitral regurgitation 1
7. Proceed with balloon valvuloplasty if all criteria are met 1

Expected Outcomes

Short-term results demonstrate significant hemodynamic improvement. In clinical series, mean mitral valve area increased from 1.0-1.06 cm² to 1.9-2.64 cm², transmitral gradient decreased from 15.7-23.1 mm Hg to 7.5-7.6 mm Hg, and cardiac index improved from 2.5-3.4 L/min/m² to 2.9-4.26 L/min/m². 4, 5 Clinical success rates range from 71-87% in experienced centers. 4

Critical Pitfalls to Avoid

• Do not perform balloon dilation in parachute mitral valves or other congenital variants with unfavorable anatomy (shortened chordae, decreased interchordal spaces, single papillary muscle), as outcomes are poor and surgical repair is preferred. 6, 2

• Operator experience matters significantly. Success rates improve from 60% in the first 20 cases to 80% with increased experience, reflecting a learning curve related to patient selection, balloon sizing, and technical refinements. 4, 7

• Patients with thick, calcified valve leaflets with extensive subvalvular involvement have unfavorable outcomes and increased procedural risks. 7

• Complications include severe mitral regurgitation (requiring emergency valve replacement), cardiac tamponade, and atrial septal defect creation. 4, 7

Special Populations

• Pregnant patients with symptomatic mitral stenosis are candidates for BMV when medical management fails. 8

• Patients with multivalvular disease require individualized assessment, though when severe aortic stenosis coexists with rheumatic mitral stenosis, catheter-based intervention for mitral stenosis is appropriate. 9

• Perioperative patients with severe mitral stenosis may benefit from balloon mitral valvuloplasty before high-risk noncardiac surgery. 2