Unifocalization and complete cardiac repair of tetralogy of Fallot with pulmonary atresia and collaterals

Professor of Cardiothoracic Surgery, Director of Pediatric Heart Center, Lucile Packard Children's Hospital, Stanford University, Palo Alto, California, USA
Frank L. Hanley

Tetralogy of Fallot with pulmonary atresia and major aorto-pulmonary collaterals remains a challenging cardiac lesion. The goal of surgical therapy for this lesion is to create separated ﾒin seriesﾓ pulmonary and systemic circulations with the lowest possible right ventricular pressure. Since the collateral circulation can be extremely complex and extremely variable, an independent approach to each individual patient is warranted. The traditional approaches have been (1) staged unifocalization using sequential left and right thoracotomies followed ultimately by a median sternotomy with VSD closure and connection of the right ventricle to the reconstructed central pulmonary arteries; or (2) various surgical palliations to encourage growth of hypoplastic central pulmonary arteries, followed by further unifocalization procedures, and finally intracardiac repair.
The limited outcome achieved with the traditional approach has stimulated us to pursue an alternative management approach, one stage unifocalization and complete repair. The advantages of this approach will be reviewed. This approach achieves a complete unifocalization early in life, when the various lung segments are still in a relatively healthy state. Additionally, it avoids the iatrogenic stenosis and fibrosis of the pulmonary arteries seen with multiple procedures, a process which often does not allow subsequent mobilization of collaterals and primary tissue to tissue anastomoses. The one stage approach also minimizes the use of nonviable material emphasizing tissue to tissue anastomoses in all cases.
We believe that this approach minimizes the time related loss of lung segments which otherwise would occur with longer delays. These losses can be due to either occlusion of collaterals, or to development of pulmonary vascular obstructive disease. It also limits the total number of operations that an individual will undergo.
Our current management protocol involves midline sternotomy one stage unifocalization and cardiac repair at about 3-4 months of life as the procedure of choice. Although closure of the ventricular septal defect and right ventricular outflow reconstruction is preferred at the time of the complete unifocalization, in some cases (about 30%) VSD closure is not advisable. Based on objective criteria the VSD closure may not be performed at the time of the complete unifocalization, but is deferred to a later date. In order to make this difficult intraoperative decision, we have developed and formalized an intraoperative pulmonary flow study, which allows us to objectively measure pulmonary vascular resistance after the unifocalization component of the operation is completed, but before the intracardiac component of the operation is undertaken. The criteria used for determining VSD closure based on the intraoperative flow study will be discussed.
In a small subgroup of patients (less than 10%) who fit a very specific set of anatomic criteria, initial midline complete unifocalization is not the procedure of choice. Either a central surgical aorto-pulmonary window is created (if confluent hypoplastic true pulmonary arteries are present), or a lateral thoracotomy with single lung unifocalization is performed.
During the past 10 years we have evolved this approach for patients with major aorto-pulmonary collaterals. Our present experience includes over 200 patients. No patients have been refused surgical correction. Representative case studies will be illustrated and overall results will be reviewed, including early surgical mortality and morbidity, and midterm follow up survival and reinterventional rate. A number of important observations which have grown out of this experience will be reviewed. Speculation about the future role of surgery in this complex condition will be discussed.