Norwood Operation — Aortic Arch Reconstruction Operative purpose

In hypoplastic left heart syndrome (HLHS) and related variants, the Norwood operation establishes unobstructed systemic outflow from the right ventricle by creating a neo-aorta and a controlled source of pulmonary blood flow. The arch reconstruction phase converts a diminutive ascending aorta and ductal arch into a single, low-resistance conduit from the neo-aortic root to the descending thoracic aorta, while preserving head-vessel perfusion and minimizing the risk of future recoarctation.

Perfusion strategy and myocardial–cerebral protection

After institution of cardiopulmonary bypass (CPB) via innominate arterial cannulation with bicaval or single right-atrial venous drainage, the patent ductus arteriosus is secured to prevent competitive runoff. Cooling proceeds to the institutional target for selective antegrade cerebral perfusion (ACP). Compared with deep hypothermic circulatory arrest (DHCA), ACP—particularly under moderate hypothermia—has been associated with lower neurologic complications in infant arch reconstruction cohorts and meta-analyses [1, 2]. Near-infrared spectroscopy (NIRS) and perfusion pressure guide ACP flows; classic physiologic work demonstrates that ~20 mL/kg/min can re-establish baseline cerebral blood volume/oxygenation under ACP during neonatal arch work [3]. Teams should explicitly set guardrails for temperature, pH strategy, hematocrit, and ACP pressure/flow, then maintain stable cerebral saturations throughout rewarming to avoid reperfusion injury [1–3].

Incision and exposure

A longitudinal aortotomy is made in the descending thoracic aorta and extended cephalad across the transverse arch toward the diminutive ascending aorta. This “unrolls” the coarctation/ductal shelf and approaches the aorta–pulmonary artery (Ao–PA) kissing point to ensure anterior working length for root creation. Diseased ductal tissue and thick posterior ridges are conservatively debrided to eliminate a residual shelf while preserving healthy margins for patch purchase.

Patch selection and geometry

Patch choice is a major determinant of late arch behavior. Contemporary series show homograft and autologous pericardium yield substantially higher 2-year freedom from recoarctation than equine pericardium (≈85–86% vs ≈30%) after Norwood I arch reconstruction [4]. Earlier risk analyses also implicated patch material in reintervention hazards over long-term follow-up [5]. Practical selection therefore favors a pulmonary homograft for its pliability, low thrombogenicity, and physiologic compliance in infancy. Orient the patch so its natural curvature recreates the outer radius; size generously to achieve an “adult-like” arch curve and a wide isthmus, reducing energy loss and growth-related restenosis.

Posterior wall first: building the arch scaffold

Suturing begins distally and proceeds proximally along the posterior wall of the opened aorta. Evenly spaced, shallow bites in healthy, non-ductal tissue establish a hemostatic posterior scaffold from the proximal descending aorta across the isthmus into the transverse arch. Use continuous fine polypropylene or interrupted 7-0/8-0 sutures according to preference, but complete posterior hemostasis before progressing anteriorly—posterior bleeding is difficult to control once the root is closed.

Creating the neo-aortic root

Carry the patch onto the anterior aspect of the diminutive ascending aorta and the native main pulmonary artery (MPA) tissue that will form the neo-aortic root after the Damus–Kaye–Stansel (DKS) anastomosis. Aim for:

A proportionate sinotubular junction (avoid a long, conical root).
A smooth root-to-arch transition without a ridge at the former ductal segment.
Incremental trimming to prevent redundancy/kink; target a broad curve and generous isthmus.

If the DKS is constructed prior to arch work, integrate the anterior patch line seamlessly into the neo-root. If the DKS is deferred, preserve adequate anterior patch length to reach the pulmonary root without tension.

Completing the arch and hemostasis

After closing the anterior wall to the distal anastomosis, inspect for symmetry, caliber, and a flat posterior plane—especially across the prior ductal/isthmus region—to exclude a “hidden” shelf. Seal isolated needle holes judiciously; avoid over-sewing that narrows the neonatal arch.

Transition off ACP and rewarming

Once hemostasis is secured, discontinue ACP, resume full CPB, and rewarm. Many surgeons complete the distal anastomosis of the right-ventricle–to–pulmonary artery (RV–PA) conduit during rewarming (e.g., a “distal dunk” technique), then construct the proximal RV outflow anastomosis; the dunk approach can mitigate distal stenosis and bleeding at the pulmonary artery insertion [8]. Compared with a modified Blalock–Taussig shunt, an RV–PA conduit typically provides higher diastolic aortic/coronary perfusion pressures and early survival advantages in randomized and modeling studies, supporting its physiologic rationale for Stage I [6, 7].

Intraoperative assessment

Before separation from bypass, ensure:

An undamped arterial tracing and no upper–lower extremity gradient.
Cerebral/somatic NIRS recovery to baseline.
Echocardiography confirming unobstructed flow from neo-root to descending aorta, a smooth DKS geometry without neoaortic insufficiency, and no patch billow/kinking.
An appropriately sized, unobstructed RV–PA conduit with preserved branch PA caliber.

Technical pearls and pitfalls

Generosity beats symmetry. A slightly larger outer curve is safer than a tight arch that will re-obstruct as somatic growth outpaces patch compliance.
Eliminate the ductal shelf. Incorporate the posterior ridge fully to avoid a nidus for recoarctation [4, 5, 9–11].
Respect root proportion. Over-long, narrow roots predispose to neoaortic insufficiency and energy loss.
Use the patch’s natural curvature. Forcing a flat course increases wall stress/turbulence.
Secure posterior hemostasis early. Re-exposure under renewed ACP or DHCA is avoidable with a disciplined posterior-first plan.
RV–PA timing matters. A distal dunk during rewarming keeps the ACP field uncluttered and may reduce distal conduit issues [8].

Early postoperative priorities

Vigilant surveillance for arch obstruction (upper–lower extremity pressure/saturation differential) with prompt imaging if suspected; most reinterventions cluster in the first six months after Norwood [5].
Deliberate systemic–pulmonary flow balance (ventilation to temper PBF; nuanced inotropy/afterload).
Antithrombotic therapy per institutional protocol for homograft/conduit.
Pre-discharge echocardiography documenting arch gradients, neo-aortic valve function, and RV–PA conduit patency.

Evidence highlights (from the literature synthesized into the text above)

Neuroprotection. In infant arch reconstruction, ACP (often at moderate hypothermia) is associated with fewer neurologic complications than DHCA; classic physiologic data support ACP flows around 20 mL/kg/min with NIRS-guided titration [1–3].
Patch choice. Homograft/autologous pericardium outperform equine pericardium for 2-year freedom from recoarctation after Norwood I [4], and patch material remains a long-term risk signal [5].
Recoarctation. Reintervention rates after Norwood I vary widely across centers; risk is concentrated early and relates to arch geometry, ductal tissue handling, and baseline ascending aorta size—with the smallest diameters (≤1.5 mm) experiencing the greatest early morbidity/mortality and higher reintervention rates [5, 9–11].
Pulmonary blood-flow source. RV–PA conduits provide higher diastolic/aortic and coronary perfusion and showed early survival benefit vs MBTS in the SVR trial; computational studies corroborate the hemodynamic advantages [6, 7].
Technique refinements. A distal dunk RV–PA insertion can decrease distal conduit stenosis and bleeding [8].

References

[1] Kornilov IA, Sinelnikov YS, Merzlyakov VY, et al. Outcomes after aortic arch reconstruction for infants: deep hypothermic circulatory arrest versus moderate hypothermia with selective antegrade cerebral perfusion. Eur J Cardiothorac Surg. 2015;48(3):e45–e52.

[2] Tian DH, Wan B, Bannon PG, Misfeld M, LeMaire SA, Kazui T. A meta-analysis of deep hypothermic circulatory arrest versus moderate hypothermia with selective antegrade cerebral perfusion in aortic arch surgery. Ann Cardiothorac Surg. 2013;2(2):148-158.

[3] Pigula FA, Nemoto EM, Griffith BP, Siewers RD. Regional low-flow perfusion provides cerebral circulatory support during neonatal aortic arch reconstruction. J Thorac Cardiovasc Surg. 2000;119(2):331-339.

[4] Vitanova K, Cleuziou J, Hörer J, et al. Recoarctation after Norwood I procedure for hypoplastic left heart syndrome: impact of patch material. Ann Thorac Surg. 2017;103(2):617-623.

[5] Ashcraft TM, Jones K, Border WL, et al. Factors affecting long-term risk of aortic arch recoarctation after the Norwood procedure. Ann Thorac Surg. 2008;85(4):1397-1401.

[6] Ohye RG, Sleeper LA, Mahony L, et al.; Pediatric Heart Network Investigators. Comparison of shunt types in the Norwood procedure for single-ventricle lesions. N Engl J Med. 2010;362(21):1980-1992.

[7] Mroczek T, Kurpesa M, Janas J, et al. Norwood with right ventricle-to-pulmonary artery conduit is more effective than Norwood with Blalock-Taussig shunt for hypoplastic left heart syndrome: mathematic modeling of hemodynamics. Thorac Cardiovasc Surg. 2011;59(4):236-244.

[8] Mascio CE, Pasquali SK, Wallace A, et al. Distal dunk for right ventricle to pulmonary artery shunt in stage 1 palliation. Ann Thorac Surg. 2015;101(1):381-383.

[9] Cleuziou J, Vitanova K, Hörer J, et al. Recoarctation after the Norwood I procedure for hypoplastic left heart syndrome: incidence, risk factors and treatment. Interact Cardiovasc Thorac Surg. 2013;16(3):290-295.

[10] Kobayashi Y, et al. Does the size of pulmonary artery impact on recoarctation after the Norwood procedure? J Thorac Dis. 2021;13(3):1606-1615.

[11] Carvajal HG, Ohye RG, Donohue JE, et al. Does ascending aorta size affect Norwood outcomes in hypoplastic left heart with aortic atresia? World J Pediatr Congenit Heart Surg. 2020;11(3):305-314.