Modified Norwood/Sano Stage I Palliation for Hypoplastic Left Heart Syndrome Without Circulatory Arrest

We present to you a stage-I palliation of hypoplastic left heart syndrome (HLHS) via a modified Norwood/Sano procedure in a 3.9 kg, 6-day-old neonate with aortic and mitral valves atresia. The neonate had unrestricted atrial septum and was placed on prostaglandin infusion after birth to maintain ductal patency.

Our preference is to modify the Sano conduit prior to sternotomy by suturing the end of a 5-mm ringed Gore-Tex graft to a 7-mm aortic/pulmonary homograft valve. We believe this minimizes, if not eliminates any additional volume overload as a result of free pulmonary regurgitation compared to the typical non-valved Sano conduits.

Cardiopulmonary bypass was maintained via dual arterial (3.5-mm Gore-Tex graft to the innominate artery and descending aortic cannulation), and single right atrial cannulation.

On the beating heart, the ductus arteriosus is doubly ligated and divided. Atrial septectomy is then performed, followed by constructing the distal Sano anastomosis to the pulmonary artery bifurcation using the valved segment of the Sano conduit. The proximal Sano was completed as well using the ringed Gore-tex segment. Arch vessels are then controlled, a side biting clamp is applied on the proximal descending aorta. On beating heart, the coarctation segment is resected and the descending aortic-to-distal arch anastomosis is constructed using a running 7/0 prolene suture along the back wall. The arch is opened all the way to the distal ascendign aorta. Once the distal ascending aorta is reached, cross clamp was applied and cardioplegia is administered. This is performed at 34 degrees Celsius with both the head and the body perfused. Modified Damus-Kaye-Stansel (DKS) aortopulmonary anastomosis is then created. A decellularized pulmonary homograft patch is then used in a Norwood type fashion to augment the aortic anastomosis, arch, ascending aorta and the DKS anteriorly. We trim the patch as we go thus creating an adequate size neoaorta. This is followed by de-airing and removal of clamps.

The Sano conduit is then completed by sewing the valved homograft segment to the ringed Gore-Tex segment. The patient is weaned off cardiopulmonary bypass without difficulty.

Postbypass transesophageal echocardiography confirmed the patency of the aortic arch and the unobstructed flow in the Sano conduit with good ventricular function. The patient is decannulated.

We performed intraoperative fluorescent angiography using indocyanine green (ICG) which confirmed good myocardial perfusion and good visualization of epicardial coronary arteries.

The patient tolerated the procedure well and the chest was closed in a delayed fashion 2 days later. He was extubated on the 9th postoperative day with excellent hemodynamics.

References

1. Reinhartz O, Reddy VM, Petrossian E, MacDonald M, Lamberti JJ, Roth SJ, Wright GE, Perry SB, Suleman S, Hanley FL. Homograft valved right ventricle to pulmonary artery conduit as a modification of the Norwood procedure. Circulation. 2006 Jul 4;114(1 Suppl):I594-9.
2. Said SM, Dearani JA. Norwood valved Sano shunt: Early reward versus late penalty? J Thorac Cardiovasc Surg. 2018 Apr;155(4):7
3. Mascio CE, Spray TL. Distal Dunk for Right Ventricle to Pulmonary Artery Shunt in Stage 1 Palliation. Ann Thorac Surg. 2015 Dec;100(6):2381-2
4. Supplemental Perfusion Techniques for Aortic Arch Reconstruction, With Emphasis on Direct Cannulation of the Descending Aorta.
5. Hammel JM. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2019;22:14-20

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