Interrupted Aortic Arch — #6 Single Ventricle Pathway

Date
November 12, 2025
URL
https://x.com/WithAScalpel/status/1988592305381491110?s=20
Categories
Interrupted Aortic ArchCardiac Surgery

Interrupted Aortic Arch — #6 Single Ventricle Pathway

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When and why this pathway is chosen

A single-ventricle strategy is selected when the left-sided structures are too small or dysfunctional to support a durable biventricular repair—e.g., a diminutive LV, hypoplastic mitral/aortic valves, a tiny ascending aorta, and an obligate VSD that cannot be recruited to a reliable LVOT. Contemporary multi-institutional data show that among neonates with IAA+VSD and severe LVOTO, both primary and staged biventricular solutions are feasible with low operative mortality, but the single-ventricle pathway remains appropriate when LV/valvar dimensions and LVOT geometry are prohibitive [1]. In population-level follow-up after IAA repair, staged approaches and type B anatomy carry higher long-term mortality risk, underscoring the value of avoiding staged systemic repairs when biventricular adequacy is clearly absent yet neo-aortic reconstruction can be done safely within a Norwood-type plan [5]. PubMed+1

Stage I (Norwood-type operation)

Physiologic objectives

  • Convert the RV into the systemic pump and supply unobstructed coronary and head/neck perfusion.
  • Eliminate ductal dependency and re-establish arch continuity.
  • Provide a controlled source of pulmonary blood flow (PBF).

Key components

  • Damus–Kaye–Stansel (DKS) anastomosis. Main PA to diminutive ascending aorta/neo-aorta, routing RV output to the systemic tree and coronaries.
  • Comprehensive arch reconstruction. Wide ductal resection and generous patch augmentation from ascending to descending aorta to prevent shelf/torsion.
  • Pulmonary blood flow source. Either an RV–PA conduit (Sano) or a modified BT shunt, sized to balance Qp:Qs and minimize diastolic runoff/coronary steal.
  • VSD management. The VSD is left open; it is not a systemic outflow route in this pathway, and premature closure risks inadequate ventricular decompression.

Technical pearls

  • Construct a straight, non-kinked neo-aorta; prioritize a smooth inner curvature in the distal arch to reduce gradients and late recoarctation.
  • With an RV–PA conduit, avoid RV free-wall distortion and preserve branch PA geometry for Glenn candidacy.
  • Size shunt/conduit to patient size, PVR, and ventricular performance; oversizing risks heart failure and coronary ischemia from runoff, undersizing risks hypoxemia.

(Technical points above reflect widely adopted Norwood principles; selection of conduit vs mBT is often individualized and center-specific.)

Interstage priorities (Stage I → Glenn)

  • Perfusion balance. Target stable saturations (mid-70s to mid-80s), appropriate weight gain, and no persistent acidosis.
  • Surveillance of failure points: neo-aortic arch (recoarctation), RV–PA conduit or BT shunt stenosis, branch PA distortion, AV valve regurgitation, and RV dysfunction.
  • Medication/anticoagulation per institutional protocol to protect shunt/conduit and optimize loading conditions.

Longitudinal registry data reinforce vigilance: recurrent arch obstruction and shunt/conduit issues are common “tune-up” targets across the interstage period and beyond [5]. PubMed

Stage II and III

  • Bidirectional Glenn. When PVR is low and branch PAs are adequate, routing SVC flow directly to the PAs unloads the RV and improves systemic efficiency.
  • Fontan completion. Routing IVC flow to the PAs completes a ventricle-less pulmonary circuit. Durable success depends on low PVR, unobstructed PAs, competent AV valve(s), and preserved ventricular/hepatic function.

Potential for later transition to biventricular repair

A minority will demonstrate sufficient somatic and left-heart growth to pursue a biventricular conversion, most often a Yasui (Norwood arch with intraventricular baffle to the neo-aorta) when LV size and VSD position allow. Modern series of Yasui (primary or staged after a Norwood/hybrid) show low operative mortality with frequent reintervention, largely expected conduit exchanges; these data support cautious optimism when anatomy is favorable but should not be promised a priori [1–3]. Tailored algorithms that mitigate LVOTO risk during IAA/VSD repairs further clarify who can be steered toward biventricular strategies and who is best served by single-ventricle palliation [4]. PubMed+3PubMed+3PubMed+3

Expected reinterventions and long-term considerations

  • Arch reintervention (balloon or surgical) for recurrent obstruction.
  • Conduit/shunt revisions and PA angioplasty/stenting across stages.
  • Lifelong surveillance for AV valve regurgitation, neo-aortic insufficiency, arrhythmia, ventricular dysfunction, protein-losing enteropathy, and thromboembolism typical of Fontan physiology.
  • Emphasize nutrition, growth, and infection prevention through the interstage period; any desaturation or low-output signal warrants urgent evaluation for shunt/conduit compromise.

    • These expectations align with registry-level observations that long-term outcomes depend on anatomy (e.g., type B IAA), avoidance of staged systemic repairs when feasible, and careful management of LVOTO-related issues [5]. PubMed

References

[1] Nellis JR, Scherba JC, Meza JM, Turek JW, Andersen ND. Primary vs staged biventricular repair for neonatal interrupted aortic arch with ventricular septal defect and left ventricular outflow tract obstruction. Ann Thorac Surg Short Rep. 2024;2(4):815-819. PubMed

[2] Carrillo SA, Mainwaring RD, Schaffer JM, Wright G, Maeda K, Hanley FL, Reddy VM. Contemporaneous comparison of the Yasui and Norwood procedures at a single institution. J Thorac Cardiovasc Surg. 2015;149(2):508-513. PubMed

[3] Kanter KR, Kirshbom PM, Kogon BE. Biventricular repair with the Yasui operation (Norwood/Rastelli) for systemic outflow tract obstruction with two adequate ventricles. Ann Thorac Surg. 2012;93(6):1999-2005. PubMed

[4] Alsoufi B, Schlosser B, McCracken C, Sachdeva R, Kogon B, Border W, Mahle WT, Kanter K. Selective management strategy of interrupted aortic arch mitigates left ventricular outflow tract obstruction risk. J Thorac Cardiovasc Surg. 2016;151(2):412-420. PubMed

[5] Miller JC, Velani RN, Miller WD, Thomas AS, Shaw FR, Kochilas L. Long-term outcomes after interrupted aortic arch repair. Ann Thorac Surg. 2024;118(2):469-477. PubMed

[6] Mallios DN, Gray WH, Cheng AL, et al. Biventricular repair in interrupted aortic arch and ventricular septal defect with a small left ventricular outflow tract. Ann Thorac Surg. 2021;111(2):637-644. PubMed