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The Norwood Procedure With Coronary Transfer to the Pulmonary Root: A Modification Proposed by Me or by God?

Monday, June 18, 2018

Al-Jughiman M. The Norwood Procedure With Coronary Transfer to the Pulmonary Root: A Modification Proposed by Me or by God?. June 2018. doi:10.25373/ctsnet.6492590.

In 2014, I was a third year resident in a cardiac surgery residency program pursuing my academic enrichment year. By that time, I had already read several publications confirming and discussing the suboptimal coronary perfusion after the Norwood procedure [1-5]. Thus, in my academic year I started to think of a new modification that could address this concern. I had the opportunity to attend the pathology museum and examine some specimens of hypoplastic left heart syndrome. The first idea that came to my mind was to incorporate the native hypoplastic aortic root with the amalgamation of the ascending aorta and pulmonary artery, creating a common arterial trunk with a common arterial valve. It sounded too complicated and unfeasible for me! One day, I was in the pathology museum examining a heart specimen after a Norwood procedure. I was focusing on the coronary buttons arising from very hypoplastic aortic sinuses and appreciating the amalgamation of the ascending aorta with the pulmonary artery being above the hypoplastic aortic root. The idea of coronary transfer to the pulmonary root immediately came to my mind.

As we know, the aortic sinuses have an important function in the normal physiology of coronary blood flow.  In the modern era, surgical innovation requires extensive investigation and assessment before clinical implementation. The days when surgeons can experiment with new and unproven surgical techniques are gone. As such, given the advancements in the facilities and technologies we currently have, I strongly believe that we are in an era where “we should always simulate before we innovate.”

Computational fluid dynamics (CFD) and other advanced mathematical methods provide a unique and novel platform to test the feasibility and potential benefits or risks of surgical innovation. However, one must start with an identifiable and existing problem, for which we all recognize and understand the pathogenesis. Based on this, I decided to pursue a CFD study to evaluate the hemodynamic effect of our proposed modification compared to the original Norwood [6]. In the midst of our work, Saiki and colleagues from Japan published their study [7]. This study makes me more convinced of the necessity to address this problem, as it confirms the coronary malperfusion after the Norwood procedure even with the use of a Sano shunt.

While reviewing the literature to determine if this modification was ever proposed, I found an article published in the Journal of the American College of Cardiology in 1984 by Bharati and colleagues and entitled “Origin of Both Coronary Arteries From the Pulmonary Trunk Associated With Hypoplasia of the Aortic Tract Complex: A New Entity” [8]. Interestingly, the authors reported a baby who was born with hypoplastic left heart syndrome, with both of the coronary arteries arising from the pulmonary trunk. The patient was seen by a cardiac surgeon who considered the defect inoperable, and the patient died on the third hospital day. Although the defect had been deemed inoperable, the authors discussed the surgical options available at that time including the Norwood procedure, which had been very recently introduced when this child's heart defect was reported [9-10]. Had the Norwood procedure been performed in this patient, the main pulmonary trunk with the coronary arteries and the right ventricle would have been rendered the systemic circuit.

Honestly, I felt that I was proposing a modification that almighty God himself had already proposed 35 years ago, concomitant with the introduction of Dr Norwood’s procedure.


  1. Donnelly JP, Raffel DM, Shulkin BL, et al. Resting coronary flow and coronary flow reserve in human infants after repair or palliation of congenital heart defects as measured by positron emission tomography. J Thorac Cardiovasc Surg. 1998;115(1):103-110.
  2. Voges I, Jerosch-Herold M, Hedderich J, et al. Maladaptive aortic properties in children after palliation of hypoplastic left heart syndrome assessed by cardiovascular magnetic resonance imaging. Circulation. 2010;122(11):1068-1076.
  3. De Oliveira NC, Ashburn DA, Khalid F, et al. Prevention of early sudden circulatory collapse after the Norwood operation. Circulation. 2004;110(11 Suppl 1):II133–138.
  4. Furck AK, Hansen JH, Uebing A, Scheewe J, Jung O, Kramer HH. The impact of afterload reduction on the early postoperative course after the Norwood operation - a 12-year single-centre experience. Eur J Cardiothorac Surg. 2010;37(2):289-295.
  5. Feinstein JA, Benson DW, Dubin AM, et al. Hypoplastic left heart syndrome: current considerations and expectations. J Am Coll Cardiol. 2012;59(1 Suppl):S1-42.
  6. Al-Jughiman MK, Al-Omair MA. Modelling coronary flow after the Norwood operation: influence of a suggested novel technique for coronary transfer. Glob Cardiol Sci Pract. 2018;2018(1):7.
  7. Saiki H, Kuwata S, Kurishima C, Masutani S, Senzaki H. Vulnerability of coronary circulation after Norwood operation. Ann Thorac Surg. 2016;101(4):1544-1551.
  8. Bharati S, Szarnicki RJ, Popper R, Fryer A, Lev M. Origin of both coronary arteries from the pulmonary trunk associated with hypoplasia of the aortic tract complex: a new entity. J Am Coll Cardiol. 1984;3(2 Pt 1):437-441.
  9. Norwood WI, Lang P, Castaneda AR, Campbell DN. Experience with operations for hypoplastic left heart syndrome. J Thorac Cardiovasc Surg. 1981;82(4):511-519.
  10. Norwood WI, Lang P, Hansen DD. Physiologic repair of aortic atresia-hypoplastic left heart syndrome. N Engl J Med. 1983;308(1):23-26.


Donnelly and colleagues studied the rest and reserve myocardial perfusion using positron emission tomography in patients after anatomic repair of a congenital heart lesion, and after Norwood procedure for HLHS. Notably, all patients with the Norwood procedure in this study had Blalock-Taussig shunt. It is well perceived that there is a diastolic runoff through the BT shunt, creating a diminished diastolic perfusion pressure for the coronary circulation. In this study, the resting coronary flow was significantly less in the Norwood group. Although the coronary flow reserve was not significantly different between the two groups, oxygen delivery to the systemic ventricle was significantly less in the Norwood group at both rest and during adenosine hyperemia. Saiki and colleagues measured the sub-endocardial viability ratio in 29 patients with HLHS post Norwood procedure, in 27 patients with pulmonary atresia with aorto-pulmonary shunt, and in 30 control patients who had normal biventricular circulation. They selected patients with PA and AP shunt as disease controls, because the AP shunt produces diastolic runoff, which could potentially jeopardize coronary perfusion. In this study, all patients with the Norwood procedure had right ventricle to pulmonary artery shunt or the Sano shunt. In this study, the sub-endocardial viability ratio in the Norwood patients was significantly lower than the control group, and significantly lower than patients with PA and AP shunt which is the disease control group. Importantly, the authors of this study found that the stiffness index of the aorta was significantly higher in the Norwood group than in the control and disease control groups. In multivariate analysis, they identified the stiffness index of the aorta and aortic size discrepancy as independent determinants of the sub-endocardial viability ratio. This study indicated that patients post Norwood procedure even if they received Sano shunt would have a suboptimal coronary perfusion compared to normal, and compared to other congenital heart lesions even with aorto-pulmonary shunt. In other words, coronary mal-perfusion is an intrinsic to the Norwood circulation, and the diastolic runoff associated with BT shunt is only one factor influencing the coronary perfusion after the Norwood procedure. According to the authors of this study, increased aortic stiffness and aortic size discrepancy seemed to be more important patho-physiologies of the reduced sub-endocardial viability ratio post Norwood procedure. From these two and several other studies, we can conclude that coronary perfusion after the Norwood procedure is suboptimal whether BT shunt or Sano shunt was used. We believe that this makes it necessary to think of a new modification that would address this concern. As we discussed, the general goal of our study was to evaluate the hemodynamic effect of our proposed modification, the coronary transfer to the pulmonary root during the Norwood procedure. It is obviously a technically demanding modification. In our study, we could not evaluate the technical feasibility of our modification. The question that would arise, is this modification feasible in all aortic root sizes?, if not, what is the minimum aortic root size with which this modification becomes feasible?, for example is it 3 mm, less or more?. Once we finish evaluating our fourth hypothesis, we are planning to survey congenital heart surgeons’ thoughts and opinions on this modification including its technical feasibility.

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