eComment: Re: In hypoplastic left heart patients is Sano shunt compared with modified Blalock–Taussig shunt associated with deleterious effects on ventricular performance?

We have read this article with interest [1]. However, when studying the influence of small ventriculotomy on ventricular performance, all effects of each Norwood modification must be taken into account.

We analyzed hypoplastic left heart patients with Sano shunt and modified Blalock–Taussig (mBT) shunt. We would like to note some points on the immediate postoperative outcome of these patients. Potential advantage of mBT shunt is the absence of myocardial injury but the persistent systolediastolic pulmonary blood flow is not good. To avoid intense diastolic runoff, it is necessary to support adequate diastolic blood pressure. The next significant point of early and late postoperative outcomes of these patients is the risk of coronary steal syndrome. In patients with RV-PA shunt the single ventricle would ensure an adequate cardiac output in both systemic and pulmonary beds. Systolic pulmonary blood flow with a partial return to the ventricle during the diastole phase requires an increase in preload and may cause edema (this problem could be solved by the obturative element in RV-PA conduit).

Hemodynamic changes after RV-PA shunt provide better conditions for bidirectional Glenn shunt. Nakata index in patients with RV-PA is higher than in patients with mBT; pressure in the superior vena cava patients with RVPA is lower than in patients with mBT [2]. We found no significant differences in right ventricle size, shape, or estimates of systolic and diastolic function between groups, and no risks of arrhythmias.

We think that the final choice between the Norwood operation and modifications depends on the preferences of the surgeon or clinic. The main purpose of comparing the two modifications should involve two main points: the initial survival and the preparation for bidirectional Glenn shunt. Therefore, we believe it is possible to consider a third group of patients undergoing bidirectional Glenn shunt and reconstruction of systemic blood flow performed after a hybrid approach for hypoplastic left heart (stenting an open arterial duct, bilateral banding pulmonary artery) [3]. In this case, the role of the ventriculotomy ceases to be meaningful and becomes the main choice between Norwood operation with cardiopulmonary bypass and a hybrid approach for hypoplastic left heart.

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