Total artificial heart in the pediatric patient with biventricular heart failure

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 1.7 m(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 failing Fontan: what’s NEXT…?

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.

Case-control study of risk factors for the development of post-transplant lymphoproliferative disease in a pediatric heart transplant cohort

PTLD is an important complication following heart transplantation. To better define the risk factors of PTLD in children, we performed a case-control study. All pediatric cardiac transplant recipients who developed their first episode of PTLD were matched by age (+/-1 yr) and time since transplant (+/-1 yr) with those who did not. PTLD occurred in nine of 95 cardiac transplant recipients (9%), 0.3-7.8 yr following cardiac transplantation (median = 2.5 yr). Patients were 0.1-16.4 yr (median = 3.7) at transplantation. Biopsies revealed polymorphic B cell hyperplasia (three), polymorphic B cell lymphoma (one), monomorphic diffuse large cell B cell lymphoma (three) and monomorphic Burkitt's-like lymphoma (two). Patients who developed PTLD were at no greater risk of death (p = 0.31). Recipient EBV seronegativity at time of transplant (p = 0.08), EBV seroconversion (p = 0.013) and recipient CMV seronegativity (p = 0.015) were associated with the development of PTLD by conditional logistic regression; sex, race, donor age, recipient diagnosis, donor CMV seropositivity, recipient treatment for CMV infection, EBV seropositivity at the time of PTLD diagnosis, and number of rejection episodes, treated rejection episodes, and lympholytics used were not. There was no significant association between PTLD and death in our recipients. EBV seroconversion and recipient CMV seronegativity were associated with the development of PTLD.

Nutrição Pós-Eclosão de Frangos de Corte

A emergência da casca marca o final do período de incubação das aves. Esse período pode ter extremos que vão de 480 a 510 horas em galinhas domésticas. As aves precociais nascem com reservas nutricionais provenientes do albúmen e gema residuais contidos no saco vitelino, que são importantes nas primeiras horas de vida enquanto ocorre a adaptação à alimentação independente, com recursos obtidos no meio ambiente. Aparentemente, os pintainhos de corte não apresentam restrições significativas com relação à utilização dos nutrientes obtidos externamente. Uma exceção, de importância questionável, pode ser a possível redução na capacidade de emulsificação das gorduras devido a uma menor concentração de sais biliares momentaneamente disponíveis. Entretanto, o imediato alojamento com disponibilização de alimento e água acelera a adaptação das aves à vida independente e tem reflexos positivos no desempenho posterior. Atrasos no alojamento, seja ainda na câmara de eclosão, transporte ou manejo dos pintinhos, reduzem o potencial de síntese protéica muscular, especialmente na musculatura do peito. Por muitos anos, os produtores de frangos de corte têm usado programas nutricionais que incluem uma mesma dieta da eclosão até as 3 semanas de idade. Recentemente, tem havido um aumento no interesse comercial por uma dieta especializada que contemple as diferenças de adaptação dos primeiros dias de vida das aves. A existência de diferenças entre exigências nutricionais das aves nessa situação com relação a animais mais maduros é ainda uma incógnita, tendo em vista o volume pequeno de informações disponíveis.

Complications of endomyocardial biopsy in children

OBJECTIVES

To evaluate the incidence of, and risk factors for, complications of endomyocardial biopsy in children.

BACKGROUND

Endomyocardial biopsy (EMB) is a low risk procedure in adults, but there is a paucity of data with regard to performing this procedure in children.

METHODS

Retrospective review of the morbidity and mortality of 1,000 consecutive EMB procedures.

RESULTS

One thousand EMB procedures (right ventricle 986, left ventricle 14) were performed on 194 patients from July 1987 through March 1996. Indications for EMB included heart transplant rejection surveillance (846) and the evaluation of cardiomyopathy or arrhythmia for possible myocarditis (154). Thirty-seven (4%) procedures were performed on patients receiving intravenous inotropic support. There was one biopsy related death, secondary to cardiac perforation, in a two-week-old infant with dilated cardiomyopathy. There were nine perforations of the right ventricle, eight occurring in patients with dilated cardiomyopathy and one in a transplant recipient. The transplant patient did not require immediate intervention; two patients required pericardiocentesis alone, and six underwent pericardiocentesis and surgical intervention. All nine perforations were from the femoral venous approach (p < 0.01). Multivariate analysis demonstrated that the greatest risk of perforation occurred in children being evaluated for possible myocarditis (p = 0.01) and in those requiring inotropic support (p < 0.01). Other complications included arrhythmia (5) and single cases of coronary-cardiac fistula, flail tricuspid leaflet, pneumothorax, hemothorax, endocardial stripping and seizure.

CONCLUSIONS

Risk of endomyocardial biopsy is highest in sick children with suspected myocarditis on inotropic support. However, EMB can be performed safely with very low morbidity in pediatric heart transplant recipients.

Initial mechanical stability of acetabular prostheses

Secure initial stability is crucial for prostheses designed for biological ingrowth; without it, subsequent tissue ingrowth is impossible. Mechanical testing was performed in vitro to measure the interface shear stability of acetabular cup prostheses. Cemented, threaded, fined, and press-fit cups, both with and without supplemental screw fixation, were tested. A mechanically consistent polyethylene foam was used as a substrate to obviate the variations inherent in cadaver bones. Ramped, eccentric rim loads were applied using a servohydraulic materials testing system. Reaming, insertion, and loading variables were carefully controlled. Cups with external threads were significantly more stable than those fixed by fins or screws. Press-fit cups were significantly looser than all other tested designs. None of the uncemented prostheses approached the initial stability of cups secured with acrylic bone cement.