What is the treatment for pulmonary artery stenosis in children?

Treatment of Pulmonary Artery Stenosis in Children

Primary intravascular stent implantation is the definitive treatment for significant pulmonary artery stenosis in children when the vessel is large enough to accommodate a stent capable of expansion to adult diameter, while balloon angioplasty alone should be reserved for very small patients, distal stenoses, or as initial therapy where stenting is not feasible. 1

Treatment Algorithm Based on Patient Size and Lesion Location

For Larger Children with Proximal/Branch Stenosis

• Stent implantation is indicated as first-line therapy when the patient/vessel can accommodate a stent expandable to adult size (Class I recommendation) 1
• Stents achieve >90% success rates compared to 67% for balloon angioplasty alone 2
• This approach provides durable results and avoids the high restenosis rates (25%) seen with balloon angioplasty 2

For Very Small Patients or Distal Stenoses

• Balloon angioplasty is indicated when primary stent implantation is not viable due to patient size or complex anatomy (Class I recommendation) 1
• While balloon dilation produces up to 50% improvement in vessel diameter and gradient reduction, long-term durability is poor with frequent restenosis 1
• Cutting balloon angioplasty may be considered for dilation-resistant vessels 3

For Critically Ill Postoperative Patients

• Stent implantation is reasonable when significant branch pulmonary artery stenosis causes definite hemodynamic compromise, regardless of vessel size, particularly if balloon dilation fails (Class IIa recommendation) 1

Defining "Significant" Stenosis Requiring Intervention

Intervention is warranted when any of the following criteria are met 1:

• Measurable gradients of 20-30 mm Hg across the stenosis
• Right ventricular or proximal pulmonary artery pressure elevated to >50-67% of systemic pressure
• Relative flow discrepancy between lungs of 35%/65% or worse
• Subjective angiographic appearance of significant narrowing with discrepant blood flow

Important caveat: In low-flow situations (Glenn shunts, Fontan circulations), gradients are unreliable—anatomic appearance and flow distribution become primary determinants 1

Special Considerations for Small Children

For infants and small children where adult-sized stents cannot be placed 1:

• Small stents lacking adult-size potential may be implanted as part of a cooperative surgical strategy (Class IIb recommendation)
• These stents require surgical enlargement or removal during future planned operations (conduit replacement, Fontan completion)
• This approach should only be undertaken with explicit surgical team commitment for future intervention

Main Pulmonary Artery Stenosis

Primary stent implantation is reasonable for significant main pulmonary artery stenosis causing RV pressure elevation, provided the stent will not compromise the pulmonary valve or impinge on the bifurcation (Class IIa recommendation) 1

Balloon angioplasty may be considered for main pulmonary artery stenosis with pressure >67% of systemic, though this supravalvar-type stenosis responds poorly to balloon dilation alone (Class IIb recommendation) 1

Critical Technical Points

Predilation Strategy

• Routine predilation is NOT recommended due to vessel rupture risk 1
• Predilation is indicated only when:
  • Previous balloon dilation failed to achieve desired diameter
  • Stenosis is so tight (2-3 mm) that delivery sheath cannot advance without predilation 1

Risks and Complications

• Vessel rupture with massive hemothorax and potential death remains the most serious complication 1
• Successful dilation requires overdistension causing at least intimal tears—stenotic tissue has lower compliance than normal pulmonary artery, increasing rupture risk 1
• Stent migration requiring re-implantation occurs but is manageable 2

Long-term Outcomes and Follow-up

• Stent implantation maintains vessel diameter better than balloon angioplasty, though pressure gradients may increase over time due to intimal proliferation 2
• Balloon angioplasty shows no significant change in diameter or gradient at mean 28-month follow-up, but 25% restenosis rate in initial successes 2
• Multiple re-interventions for serial stent dilations are typically required as children grow 3, 4

When Surgery is Preferred

Surgical intervention should be considered for 5:

• Supravalvar pulmonary stenosis
• Stenosis at the pulmonary artery bifurcation
• Complex situations requiring combined transcatheter and surgical approaches