Successful Pediatric Cardiac Transplant From a Donor Heart With an Unexpected Myocardial Tumor Found Post-CPB by Intraoperative Transesophageal Echocardiogram

Abstract

We report the first known successful pediatric cardiac transplant from a donor with tuberous sclerosis. During the transplant, an intraoperative transesophageal echocardiogram (TEE) revealed a left ventricle outflow tract (LVOT) mass—cardiac rhabdomyoma by histopathology. CASE REPORT A 6-year-old boy presented with congestive heart failure. Transthoracic echocardiogram (TTE) revealed severe biventricular dysfunction with an ejection fraction of 10%. Ventricular function did not improve despite aggressive medical therapy, and the patient was listed for a heart transplant. The donor was a 7-year-old girl, with a medical history of tuberous sclerosis. She developed irreversible acute intracranial hypertension after a craniotomy, and the diagnosis of brain death was confirmed by angiography. TTE was technically difficult because of poor acoustic windows but showed normal right and left atrial size; intact atrial and ventricular septums; moderate left ventricular hypertrophy with cavity obliteration during systole; mild right ventricular enlargement; and normal tricuspid, mitral, and aortic valve function. Because of the severity of the recipient patient's status, the heart was accepted without further anatomic assessment, and an orthotopic heart transplant was performed. After weaning off cardiopulmonary bypass (CPB), a TEE revealed a 7-×8-mm outgrowth beneath the aortic valve in the LVOT with no obstruction; normal biventricular function; and trivial aortic regurgitation (Fig. 1). The decision was made to return to CPB, and the portion of mass protruding into the subaortic region was excised. Histopathology revealed a cardiac rhabdomyoma. After the second CPB run, TEE revealed no LVOT mass or obstruction, no other cardiac masses, normal biventricular function, and no aortic valve dysfunction.FIGURE 1.: Intraoperative transesophageal echocardiogram. Midesophageal aortic long-axis view demonstrating a 7.1-mm mass in the LVOT. LVOT, left ventricular outflow tract; LA, left atrium; ASC AO, ascending aorta; MV, mitral valve; LV, left ventricle; RV, right ventricle.Several monthly follow-up TTEs have demonstrated well-preserved allograft function with normal biventricular size and systolic function and an ejection fraction of 70%. There is no evidence of LVOT obstruction, valvular dysfunction, or mass growth. Thirty months after heart transplant, the patient is active and healthy with no signs or symptoms of cardiovascular compromise. Tuberous sclerosis is a neurocutaneous syndrome with an incidence of 1:10000. Approximately 80% of children with cardiac rhabdomyoma have a diagnosis of tuberous sclerosis (1). Large tumors may present with arrhythmias, dysfunction of cardiac valves, congestive heart failure, embolization, and inflow/outflow obstruction, (2) with LVOT obstruction being one of the rarer presentations of cardiac rhabdomyomas (3). Rhabdomyomas have a natural history of spontaneous regression; however, symptomatic impairment from outflow tract obstruction or recurrent arrhythmias is an indication for surgical resection (1). TTE of the donor had not revealed any cardiac tumors but showed moderate left ventricular hypertrophy with cavity obliteration during systole. Despite the simplicity and noninvasive technique of TTE for imaging cardiac structures, low-quality images are obtained by TTE examinations in approximately 50% of patients on mechanical ventilation such as the organ donor population (4). TEE has been widely used to assess left ventricular function and could also be a useful tool to assess cardiac anatomy during procurement of organ donors (5). TEE provides images of better resolution than TTE, providing unexpected diagnoses that are missed by TTE in up to 50% of the cases (6). This case highlights the role of TEE in the workup of the donor heart especially when the medical history is suggestive of a potential intracardiac tumor. This information could be helpful in the surgical preparation of the donor heart before transplantation. This case brings to question the practice of using only TTE to rule out cardiac pathology in heart transplant donor candidates, specifically in patients with increase risk for cardiac pathology such as tuberous sclerosis. However, this case also illustrates that donors with heart tumors should not necessarily be rejected without assessing the possibility of treatment before transplant especially in the pediatric population where donor organs are less readily available. Gracie M. Almeida-Chen1 Silvia E. Perez-Protto2 Julie Niezgoda2 Pablo Motta3 1Division of Pediatric Anesthesia Department of Anesthesiology Columbia University New York, NY 2Department of Pediatric and Congenital Heart Anesthesiology Anesthesiology Institute Cleveland Clinic Cleveland, OH 3Department of Pediatric Cardiovascular Anesthesiology Texas Children's Hospital Baylor College of Medicine Houston, TX