Faculty Bibliography

The number of children needing heart transplantation continues to rise. Although improvements in heart failure therapy, particularly durable mechanical support, have reduced waitlist mortality, the number of children who die while waiting for a suitable donor organ remains unacceptably high. Roughly, 13% of children and 25% of infants on the heart transplant waitlist will not survive to transplantation. With this in mind, the Advanced Cardiac Therapies Improving Outcomes Collaborative Learning Network (ACTION), through its Waitlist Outcomes Committee, convened a 2-day symposium in Ann Arbor, Michigan, from 2-3 November 2019, to better understand the factors that contribute to pediatric heart transplant waitlist mortality and to focus future efforts on improving the organ allocation rates for children needing heart transplantation. Using improvement science methodology, the heart failure-transplant trajectory was broken down into six key steps, after which modes of failure and opportunities for improvement at each step were discussed. As a result, several projects aimed at reducing waitlist mortality were initiated.

Aneurysm formation around the site of coarctation of aortic arch is a well-recognised complication of untreated coarctation and is associated with an increased risk of aortic rupture and mortality. We present a rare case in a teenage girl with the combination of significant aortic arch coarctation, a "cauliflower-like" saccular aneurysm, and stenosis at the origin of the left subclavian artery. She was successfully managed with a hybrid approach, which is a combination of an endovascular surgical repair (a bypass graft placement from left carotid artery to subclavian artery by a vascular surgeon) and a transcatheter covered stent placement across the stenosis and aneurysm. This case highlights the successful role of a hybrid approach in patient's who present with a combination of coarctation of the aorta and aortic arch aneurysms. This approach avoids the conventional surgical aortoplasty, which carries a higher mortality and morbidity risk in teenage patients.

We describe our experience of bivalirudin use, a newer direct thrombin inhibitor, in an infant who was supported with Berlin Heart EXCOR VAD (Berlin VAD) as bridge to transplant for 122 days without complications and without need for pump exchange. An 11-month-old girl with dilated cardiomyopathy with acute heart failure was awaiting cardiac transplant. Lack of improvement despite maximizing medical therapy and anticipating a prolonged waitlist time, she was supported with Berlin LVAD as a bridge to transplant. Anticoagulation with bivalirudin was started and titrated with a goal partial thromboplastin time of 60-90 seconds. Therapeutic anticoagulation was achieved with bivalirudin for 50% of the days (61/122 days) on a dose of 2.1 mg/kg/hour and in a narrow dose range of 1.9 to 2.3 mg/kg/hour for 80% of the days (98/122 days). Antiplatelet regimen was started initially with aspirin and clopidogrel added later. She was supported for 122 days on a single pump without any evidence of thrombus or need for pump change. Berlin VAD explant and orthotopic heart transplant with biatrial anastomosis were performed uneventfully. Explanted Berlin VAD had no evidence of clot/fibrin or thrombus formation. The child was discharged to home uneventfully 15 days after cardiac transplant.

Cancer diagnostics and therapies have improved steadily over the last few decades, markedly increasing life expectancy for patients at all ages. However, conventional and newer anti-neoplastic therapies can cause short- and long-term cardiotoxicity. The clinical implications of this cardiotoxicity become more important with the increasing use of cardiotoxic drugs. The implications are especially serious among patients predisposed to adverse cardiac effects, such as youth, the elderly, those with cardiovascular comorbidities, and those receiving additional chemotherapies or thoracic radiation. However, the optimal strategy for preventing and managing chemotherapy-induced cardiotoxicity remains unknown. The routine use of neurohormonal antagonists for cardioprotection is not currently justified, given the marginal benefits and associated adverse events, particularly with long-term use. The only United States Food and Drug Administration and European Medicines Agency approved treatment for preventing anthracycline-related cardiomyopathy is dexrazoxane. We advocate administering dexrazoxane during cancer treatment to limit the cardiotoxic effects of anthracycline chemotherapy.

BACKGROUND:In patients with repaired Tetralogy of Fallot (rTOF), pulmonary regurgitation (PR) leads to significant morbidity. Cardiac magnetic resonance imaging (CMR) is the gold standard to assess severity of PR in rTOF patients. We compared Doppler echocardiography derived indices of PR with CMR to find the best predictive parameter for hemodynamically significant (hs) PR. METHODS:This is a retrospective analysis of echocardiogram and CMR measurements. Doppler indices obtained included: PR deceleration slope, pressure half time (PHT) and PR index. Receiver operating characteristic curve analysis was used to optimize the sensitivity and specificity of selected variables in predicting hsPR. Inter-observer variability of the Doppler parameters was assessed in a random sample of 25 Doppler spectral recordings. RESULTS:and a PHT < 130 ms, demonstrated high sensitivity (93%) and high negative predictive values (98-99%). All the Doppler indices demonstrated minimal inter-observer variability (PHT = 0.9, 95% CI 0.69-0.97; PRi = 0.95, 95%CI 0.83-0.98). CONCLUSION/CONCLUSIONS:Our data, with its high negative predictive values, show that Doppler derived echocardiography indices have an ability to rule out hsPR, as measured by CMR. PHT, PR index and deceleration slope correlate with hsPR and can be used as screening tools for further testing.

Congenital complete tracheal rings are usually associated with pulmonary slings. We report a rare association of congenital complete tracheal rings with hypoplastic left heart variant. A term infant with diagnosis of a mildly hypoplastic mitral valve, unicuspid aortic valve, and moderately hypoplastic aortic arch with severe coarctation underwent a hybrid procedure initially. Upon failing extubation attempts, complete tracheal rings were seen on direct laryngoscopy. The combination of the lesions resulted in a poor outcome. In patients with failure of extubation post-cardiac surgery, a diagnosis of complete tracheal rings should be included in the differential and a direct laryngoscopy should be considered.

With 5-year survival of children with cancer exceeding 80% in developed countries, premature cardiovascular disease is now a major cause of early morbidity and mortality. In addition to the acute and chronic cardiotoxic effects of anthracyclines, related chemotherapeutics, and radiation, a growing number of new molecular targeted agents may also have detrimental effects on the cardiovascular system. Survivors of childhood cancer also may have earlier development of conventional cardiovascular risk factors such as hypertension, dyslipidaemia, and diabetes, which further increase their risk of serious cardiovascular disease. This review will examine the epidemiology of acute and chronic cardiotoxicity relevant to paediatric cancer patients, including genetic risk factors. We will also provide an overview of current screening recommendations, including the evidence regarding both imaging (e.g. echocardiography and magnetic resonance imaging) and blood-based biomarkers. Various primary and secondary prevention strategies will also be discussed, primarily in relation to anthracycline-related cardiomyopathy. Finally, we review the available evidence related to the management of systolic and diastolic dysfunction in paediatric cancer patients and childhood cancer survivors.

OBJECTIVES:To describe characteristics of liver transplant patients with severe sepsis in the PICU. DESIGN:Retrospective descriptive analysis. SETTING:Tertiary children's hospital PICU. PATIENTS:Liver transplant recipients admitted January 2010 to July 2016 for pediatric severe sepsis. INTERVENTIONS:None. MEASUREMENTS AND MAIN RESULTS:Between January 2010 and July 2016, 173 liver transplants were performed, and 36 of these patients (21%) were admitted with severe sepsis (54 episodes total). Median age at admission was 2 years (1-6.5 yr), 47.2% were male. Bacterial infections were the most common (77.8%), followed by culture negative (12.9%) and viral infections (7.4%). Fungal infections accounted for only 1.9%. Median time from transplant for viral and culture negative infections was 18 days (8.25-39.75 d) and 25 days (9-41 d), whereas 54.5 days (17-131.25 d) for bacterial infections. Bloodstream and intra-abdominal were the most common bacterial sites (45% and 22.5%, respectively). Multidrug-resistant organisms accounted for 47.6% of bacterial sepsis. Vancomycin-resistant Enterococcus and extended-spectrum beta-lactamase producers were the most frequently identified multidrug-resistant organisms. Patients with multidrug-resistant organism sepsis demonstrated higher admission Pediatric Logistic Organ Dysfunction scores (p = 0.043) and were noted to have an odds ratio of 3.8 and 3.6 for mechanical ventilation and multiple organ dysfunction syndrome, respectively (p = 0.047 and p = 0.044). Overall mortality was 5.5% (n = 2 patients), with both deaths occurring in multidrug-resistant organism episodes. CONCLUSIONS:We report that multidrug-resistant organisms are increasingly being identified as causative pathogens for sepsis in pediatric liver transplant recipients and are associated with significantly higher odds for mechanical ventilation and higher organ failure. The emergence of multidrug-resistant organism infections in pediatric liver transplant patients has implications for patient outcomes, antibiotic stewardship, and infection prevention strategies.