Pophal, Stephen

Abstract Background Listed pediatric heart transplant patients have the highest solid‐organ waitlist mortality rate. The donor‐recipient body weight ( DRBW ) ratio is the clinical standard for allograft size matching but may unnecessarily limit a patient's donor pool. To overcome DRBW ratio limitations, two methods of performing virtual heart transplant fit assessments were developed that account for patient‐specific nuances. Method 1 uses an allograft total cardiac volume ( TCV ) prediction model informed by patient data wherein a matched allograft 3‐D reconstruction is selected from a virtual library for assessment. Method 2 uses donor images for a direct virtual transplant assessment. Methods Assessments were performed in medical image reconstruction software. The allograft model was developed using allometric/isometric scaling assumptions and cross‐validation. Results The final predictive model included gender, height, and weight. The 25th‐, 50th‐, and 75th‐percentiles for TCV percentage errors were −13% (over‐prediction), −1%, and 8% (under‐prediction), respectively. Two examples illustrating the potential of virtual assessments are presented. Conclusion Transplant centers can apply these methods to perform their virtual assessments using existing technology. These techniques have potential to improve organ allocation. With additional experience and refinement, virtual transplants may become standard of care for determining suitability of donor organ size for an identified recipient.

Neonatal critical aortic stenosis is life threatening and requires intervention shortly after birth. Early percutaneous aortic valvuloplasty is generally considered to be an effective way to obtain reliable prograde flow. We describe the integrated use of hybrid, open surgical, and single ventricle rehabilitation techniques to successfully treat a neonate with borderline left-sided cardiac structures, who sustained a complication from balloon aortic valvuloplasty.

Mechanical circulatory support emerged for the pediatric population in the late 1980s as a bridge to cardiac transplantation. The Total Artificial Heart (TAH-t) (SynCardia Systems Inc., Tuscon, AZ) has been approved for compassionate use by the Food and Drug Administration for patients with end-stage biventricular heart failure as a bridge to heart transplantation since 1985 and has had FDA approval since 2004. However, of the 1,061 patients placed on the TAH-t, only 21 (2%) were under the age 18. SynCardia Systems, Inc. recommends a minimum patient body surface area (BSA) of 1.7 m 2 , thus, limiting pediatric application of this device. This unique case report shares this pediatric institution’s first experience with the TAH-t. A 14-year-old male was admitted with dilated cardiomyopathy and severe biventricular heart failure. The patient rapidly decompensated, requiring extracorporeal life support. An echocardiogram revealed severe biventricular dysfunction and diffuse clot formation in the left ventricle and outflow tract. The decision was made to transition to biventricular assist device. The biventricular failure and clot formation helped guide the team to the TAH-t, in spite of a BSA (1.5 m 2 ) below the recommendation of 1.7m 2 . A computed tomography (CT) scan of the thorax, in conjunction with a novel three-dimensional (3D) modeling system and team, assisted in determining appropriate fit. Chest CT and 3D modeling following implantation were utilized to determine all major vascular structures were unobstructed and the bronchi were open. The virtual 3D model confirmed appropriate device fit with no evidence of compression to the left pulmonary veins. The postoperative course was complicated by a left lung opacification. The left lung anomalies proved to be atelectasis and improved with aggressive recruitment maneuvers. The patient was supported for 11 days prior to transplantation. Chest CT and 3D modeling were crucial in assessing whether the device would fit, as well as postoperative complications in this smaller pediatric patient.

The Fontan procedure represents the final stage of the transition to single ventricle physiology. Conversion of very complex congenital heart anatomy, such as hypoplastic left heart syndrome, double-outlet right ventricle or double-inlet left ventricle, to a single ventricle has grown in popularity as morbidity and mortality have improved. As these patients grow, survivors are at risk for impaired ventricular dysfunction, plastic bronchitis, protein-losing enteropathy and late failure. Late failing Fontan patients represent a particularly vexing scenario for clinicians, as the only durable treatment option is cardiac transplantation. However, in the short-term, some of these patients require support beyond medical management, with mechanical circulatory support via extracorporeal life support or a ventricular assist device. We report the successful bridge of an adolescent female post-Fontan conversion with late severe cardiac failure. The patient was initially resuscitated with extracorporeal life support, transitioned to a single Berlin Heart EXCOR® ventricular assist device and, subsequently, underwent successful cardiac transplantation.