Severe airflow limitation after the unifocalization procedure - Clinical and morphological correlates

Background-While unifocalization techniques have improved the treatment opt ions in patients with pulmonary atresia, ventricular septal defect (PA-VSD) , and major aortopulmonary collaterals (MAPCAs), severe airflow limitation contributes to significant early postoperative morbidity and mortality. Alt hough this has been attributed to bronchospasm, characteristically it is re fractory to bronchodilators, suggesting that other mechanisms may play a ro le. Methods and Results-The clinical course and preoperative angiograms of pati ents who underwent unifocalization were reviewed. Patients who developed ai rflow limitation early after surgery underwent Fiberoptic bronchoscopy. In addition, the anatomy of the MAPCAs was examined in 14 heart-lung blocks fr om patients with PA-VSD, Twenty-two procedures were performed in 16 childre n. Three developed marked airflow limitation early after surgery, necessita ting prolonged high-pressure ventilation. Bronchoscopy demonstrated tracheo bronchial epithelial necrosis in 2 and signs of tracheobronchial ischemia i n the third. Two were successfully extubated after 15 and 16 days, but the third died after 57 days of ventilatory support. Review of the preoperative angiograms demonstrated an extensive peribronchial arterial supply arising from a MAPCA in 1 of the patients who developed severe airway necrosis aft er unifocalization. This was also obvious in a second patient, but the MAPC A was not included in the unifocalization. In 7 autopsy specimens, MAPCAs c ontributed to a peribronchial or peritracheal vascular network. Dissection of the distribution of these branches in 2 specimens revealed extensive int rapulmonary peribronchial anastomoses, Conclusions-Airflow limitation early after unifocalization is related to ai rway ischemia resulting from interruption of the tracheobronchial blood sup ply during mobilization of MAPCAs.