Pulmonary Arterial Hypertension After Busulfan Administration During Conditioning Regimen in Neuroblastoma: Key Role of Rescue Treatment

Background: Pulmonary arterial hypertension (PH) is a rare and life-threatening complication of high-dose chemotherapy with busulfan (Bu) used for hematopoietic stem cell transplantation. Case Summary: A 5-year-old male patient with retroperitoneal neuroblastoma developed PH and acute right-sided heart failure 2 months after conditioning regimen that included Bu and melphalan before autologous hematopoietic stem cell transplantation. Once pulmonary embolism and veno-occlusive disease were excluded by computed tomography, rescue treatment, including epoprostenol, bosentan, and sildenafil, was started, with complete regression of acute right-sided heart failure and normalization of pulmonary pressure. Discussion: Bu can cause PH through different pathophysiological mechanisms. The prompt start of rescue treatment is a cornerstone for a good outcome. In our patient, considering the absence of signs of pulmonary veno-occlusive disease on computed tomography, a triple pulmonary vasodilator therapy was started and a rapid recovery was noted. Take-Home Message: Early work-up for PH in children after Bu administration is essential to recognize a life-threatening condition requiring a rescue treatment.