Subaortic Stenosis in Single-Ventricle Physiology (#4) — Surgical Strategy: Aortic Arch Repair + Pulmonary Artery Banding

In several single-ventricle substrates—classically tricuspid atresia (TA) with TGA and double-inlet left ventricle (DILV) with TGA—systemic output depends on a limited “outlet pathway” (often the bulboventricular foramen / interventricular connection) that can become progressively restrictive, producing systemic ventricular outflow tract obstruction (SVOTO) or subaortic stenosis (SAS). After PAB, the systemic ventricle faces altered loading conditions, and in SVOTO-prone anatomy, SAS may progress over time—sometimes before overt clinical decompensation is evident. [1]

1) Why choose Arch repair + PAB when SAS is not yet significant?

This strategy is designed around two immediate priorities:

1. Restore systemic pathway continuity
• Repair of coarctation/arch hypoplasia/interrupted arch removes ductal dependence and stabilizes systemic perfusion.
2. Control pulmonary overcirculation (“band physiology”)
• PAB limits pulmonary runoff, protects the pulmonary vascular bed, and improves the balance between systemic and pulmonary circulations—supporting a staged pathway toward cavopulmonary palliation. [2]

Key limitation (the “SAS risk”):

Even when baseline SVOTO is mild, historical experience shows that a substantial proportion of single-ventricle TGA–type physiologies develop progressive SAS/SVOTO after PAB, often prompting later intervention. [1,2]

2) Patient selection: when this is most reasonable

Best-fit scenario

• Significant arch obstruction requiring repair AND
• No or mild SAS/SVOTO at baseline (i.e., the subaortic pathway is acceptable enough that immediate DKS/BVF enlargement is not mandatory). [3]

Why not “DKS for everyone” up front?

A primary DKS strategy can be highly effective in protecting systemic outflow, but it commits early to semilunar valve–to–great vessel reconstruction and its downstream reintervention profile. Many contemporary approaches therefore emphasize anatomic individualization and trajectory prediction of SVOTO. [3]

3) Operative priorities and “must-not-miss” technical points

A. Arch repair

• Aim for a nonrestrictive reconstruction with durability and growth potential.
• Residual arch gradient increases ventricular work and can unmask or accelerate SVOTO physiology postoperatively—so “arch adequacy” is not optional.

B. Pulmonary artery banding

PAB is not simply “flow control.” In SVOTO-prone anatomy, it can reshape the hemodynamic environment that determines whether the subaortic pathway remains stable or becomes restrictive. [1,4]

Conceptual targets (avoid strict numbers here):

• Adequate systemic perfusion without excessive pulmonary runoff
• Acceptable oxygen delivery
• Controlled ventricular filling pressures (avoid too tight → low output; too loose → pulmonary overcirculation)

Anatomic stewardship

• Preserve branch PA geometry (avoid distortion/stenosis), because future Glenn/Fontan success depends on accessible, symmetric pulmonary arteries.

4) The essential follow-up mindset: “SAS can be progressive.”

After arch repair + PAB, follow-up is not passive. The interstage question is:

Is the systemic outflow pathway becoming progressively restrictive?

Surveillance focus (echo-centered)

• Trend subaortic/BVF Doppler gradients and flow profiles
• Ventricular hypertrophy, diastolic filling, AV valve regurgitation
• Clinical signs of systemic output limitation (feeding intolerance, poor growth, rising lactate, escalating support)

Large series underscore that patients with single-ventricle physiology plus arch obstruction have meaningful early risk, and later reinterventions for systemic outflow protection are common—supporting a proactive surveillance posture. [5,6]

5) If SAS progresses: what are the next-step operations?

Escalation is typically aligned with the staged pathway and often timed with bidirectional Glenn (BDG) when feasible.

Option 1: Direct subaortic relief

• Subaortic muscle resection ± BVF (VSD) enlargement
• Strength: anatomically direct relief of the bottleneck
• Caution: reobstruction and patch-related issues are described in clinical series. [4,6]

Option 2: Damus–Kaye–Stansel (DKS) ± BDG

• Concept: bypass the vulnerable subaortic pathway by routing systemic ventricular output through a DKS connection, eliminating the “bottleneck.”
• Often favored when anatomy predicts high likelihood of recurrent SVOTO, or when BVF enlargement is unattractive/high risk. [5,6]

Practical algorithm (text version of your slide)

• Arch obstruction + SAS not significant → Arch repair + PAB (early)
• During follow-up:
• SAS remains mild → proceed along staged pathway (BDG when appropriate)
• SAS progresses → consider muscle resection ± BVF enlargement or DKS, often combined with BDG depending on timing and physiology [5–7]

6) Evidence snapshot: outcomes and how this fits among modern strategies

• Historical series in SVOTO-prone single-ventricle physiology show that post-banding development/progression of SAS is frequent, often driving later interventions (including DKS and/or BVF enlargement). [1,2]
• In a contemporary cohort including patients with concomitant arch obstruction, initial PAB had low early mortality and supported progression through staged palliation, with ~86% survival at 5 years after PAB and substantial transition to Glenn/Fontan; outcomes diverged with higher-risk morphologies and extracardiac/genetic anomalies. [7]
• Long-term institutional experience in single-ventricle patients with arch obstruction highlights both the early attrition risk and the principle that outcomes can be excellent once Fontan status is achieved—reinforcing the importance of early-life strategies that avoid or address systemic outflow obstruction. [6]

Contextual upgrade (adjacent decision space):

In neonatal single-ventricle palliation more broadly, comparisons of strategy bundles (including hybrid-type pathways) emphasize the same unifying principle: secure unobstructed systemic output and preserve PA accessibility for the Fontan trajectory—while anticipating the reintervention burden. [8–10]

References

[1] Jensen RA Jr, Williams RG, Laks H, Drinkwater D, Kaplan S. Usefulness of banding of the pulmonary trunk with single ventricle physiology at risk for subaortic obstruction. Am J Cardiol. 1996;77(12):1089-1093.

[2] Webber SA, LeBlanc JG, Keeton BR, Salmon AP, Sandor GG, Lamb RK, Monro JL. Pulmonary artery banding is not contraindicated in double inlet left ventricle with transposition and aortic arch obstruction. Eur J Cardiothorac Surg. 1995;9(9):515-520.

[3] Jacobs ML, Rychik J, Donofrio MT, Steven JM, Nicolson SC, Murphy JD, Norwood WI Jr. Avoidance of subaortic obstruction in staged management of single ventricle. Ann Thorac Surg. 1995;60(6 Suppl):S543-S545.

[4] Hess SL, Bricker JT, Garson A Jr, Ott DA, Reul GJ, Cooley DA. Pulmonary artery banding and subaortic stenosis in patients with single ventricle: surgical alternatives and clinical outcome. Tex Heart Inst J. 1992;19(1):15-20.

[5] Odim JN, Laks H, Drinkwater DC Jr, George BL, Yun J, Salem M, Allada V. Staged surgical approach to neonates with aortic obstruction and single-ventricle physiology. Ann Thorac Surg. 1999;68(3):962-967.

[6] Lee MGY, Brizard CP, Galati JC, Iyengar AJ, Rakhra SS, Konstantinov IE, Pflaumer A, d'Udekem Y. Outcomes of patients born with single-ventricle physiology and aortic arch obstruction: the 26-year Melbourne experience. J Thorac Cardiovasc Surg. 2014;148(1):194-201.

[7] Alsoufi B, Manlhiot C, Ehrlich A, Oster M, Kogon B, Mahle WT, Maher K, McCrindle BW, Kanter K. Results of palliation with an initial pulmonary artery band in patients with single ventricle associated with unrestricted pulmonary blood flow. J Thorac Cardiovasc Surg. 2015;149(1):213-220.

[8] Rodefeld MD, Ruzmetov M, Schamberger MS, Girod DA, Turrentine MW, Brown JW. Staged surgical repair of functional single ventricle in infants with unobstructed pulmonary blood flow. Eur J Cardiothorac Surg. 2005;27(6):949-955.

[9] Baba K, Kotani Y, Honjo O, Caldarone CA, et al. Hybrid versus Norwood strategies for single-ventricle palliation. Circulation. 2012;126(11 Suppl 1):S123-S131.

[10] Rahkonen O, Chaturvedi RR, Benson L, Honjo O, Caldarone CA, Lee KJ. Pulmonary artery stenosis in hybrid single-ventricle palliation: High incidence of left pulmonary artery intervention. J Thorac Cardiovasc Surg. 2015;149(4):1102-1110.e2.