Letter by Schranz et al Regarding Article, “Comparison of the Profiles of Postoperative Systemic Hemodynamics and Oxygen Transport in Neonates After the Hybrid or the Norwood Procedure: A Pilot Study”
To the Editor:
We appreciate the novel technique applied by Li et al1 to assess continuously the hemodynamics and oxygen transport after the Norwood (n=13) and hybrid (n=6) procedures. The results obtained and the conclusions drawn, however, may be misleading in terms of the hybrid procedure in general. In most centers, the hybrid procedure is usually not performed as described here by Li et al but is instead a minimally invasive alternative to a Norwood stage I or Sano modification.2–4 The hybrid approach performed in our center in Giessen, Germany, consists of an operation in which bilateral pulmonary bands are placed through an open chest approach in the shortest amount of time possible with immediate spontaneous breathing and a short time for intubation, followed by percutaneous duct stenting 1 to 3 days postoperatively with the patient under conscious sedation and by balloon atrioseptostomy if necessary. In the context of the article by Li et al1 and our data concerning hybrid stage I,4 we strongly believe that a newborn with hypoplastic left heart syndrome needs minimal handling comparable to that given to premature babies. In contrast to what was seen in the study by Li et al, our hybrid approach is life-saving in many compromised newborns, even those admitted because of cardiogenic shock. Bilateral pulmonary banding is used to treat congestive heart failure caused by a postnatal pulmonary run-off. Percutaneous duct stenting is the treatment of choice to reopen a narrowed duct despite prostaglandin infusion, and balloon atrioseptostomy is preferred to treat severe hypoxemia due to a highly restricted interatrial septum, usually through a staged approach. Therefore, the hybrid procedure is particularly useful in newborns with an Aristotle score above 19.5
The hybrid approach performed in Toronto1 consists of surgically placed bilateral pulmonary bands followed by placement of a modified 3.5-mm Blalock-Taussig shunt and then by transpulmonary duct stenting. Patients with a restrictive interatrial septum undergo percutaneous balloon atrioseptostomy or interatrial stenting. Additionally, in the current study, a pulmonary vein catheter was placed. Therefore, it would be very informative to know the total open chest and surgical times necessary for this hybrid approach. Considering the more favorable hemodynamic data for the Toronto hybrid after 72 hours, the results can also be interpreted to mean that the surgical interventional manipulation of the Toronto hybrid procedure is too demanding. This approach should not be considered as a prophylactic tool to avoid a coronary or cerebral perfusion problem. The approach might have a place in selected patients. The data demonstrate clearly that survival after such extensive manipulation is dependent upon effectively performed bilateral pulmonary banding combined with an unrestricted duct and upon a competent pulmonary valve. Considering latter circumstances, the higher rate-pressure product and Qp:Qs in the hybrid procedure group after 72 hours should be also interpreted as a windkessel phenomenon responsible for diastolic run-off through a wide stented duct and the additional 3.5-mm modified Blalock-Taussig shunt. Seeing such a comparable hemodynamic profile in some newborns in whom 9- to 10-mm ductal stents were used indicates that a β-blocker (atenolol 0.5 to 1 mg · kg−1 · d−1) can improve hemodynamics by reducing heart rate and systemic vascular resistance without decreasing the blood pressure.
In conclusion, Li and colleagues have studied an important area of postoperative hemodynamics and oxygen transport in neonates after hybrid and Norwood procedures, but it must be emphasized that the results cannot be translated to other, more minimally invasive hybrid approaches.
Li J, Zhang G, Benson L, Holtby H, Cai S, Humpl T, Van Arsdell GS, Redington AN, Caldarone CA. Comparison of the profiles of postoperative systemic hemodynamics and oxygen transport in neonates after the hybrid or the Norwood procedure: a pilot study. Circulation. 2007; 116 (suppl I): I-179–I-187.
Akintuerk H, Michel-Behnke I, Valeske K, Mueller M, Thul J, Bauer J, Hagel KJ, Kreuder J, Schranz D. Stenting of the arterial duct and banding of the pulmonary arteries: basis for combined Norwood stage I and II repair in hypoplastic left heart. Circulation. 2002; 105: 1099–1103.
Lacour-Gayet F, Clarke D, jacobs J, Daebritz S, Daenen W, Gaynor W, Hamilton L, Jacobs M, Maruszewski B, Pozzi M, Spray T, Stellin G, Tchervenkov C, Marvroudis A; Aristotle Committee. The Aristotle score: a complexity-adjusted method to evaluate surgical results. Eur J Cardiothorac Surg. 2004: 911–924.