Sujata Chakravarti

Antithrombotic strategies in children receiving long-term Berlin Heart EXCOR ventricular assist device therapy

BACKGROUND Thromboembolic events while receiving ventricular assist device (VAD) support remain a significant cause of morbidity and mortality despite standard anti-coagulation and anti-platelet therapies. The use of bivalirudin and epoprostenol infusions as an alternate anti-thrombotic (AT) regimen in pediatric VAD patients was reviewed. METHODS This was a retrospective record review of 6 pediatric patients (aged ≤17 years) at 2 institutions treated with bivalirudin and epoprostenol infusions while being supported with the Berlin Heart EXCOR (Berlin Heart GmbH, Berlin, Germany) VAD. RESULTS Six patients (age, 0.8-14 years; weight, 6.7-29.7 kg) were treated. Diagnoses included cardiomyopathy in 2 and congenital heart disease in 4. VAD support was left VAD in 2 and bi-VAD in 4, with duration of support of 21 to 155 days. Three patients required extracorporeal membrane oxygenation before VAD support. Bivalirudin/epoprostenol was used after recurrent thromboses on conventional medication in 3 patients, heparin-induced thrombocytopenia in 2, and in 1 patient considered high risk with a prosthetic mitral valve. The bivalirudin dose was titrated to partial thromboplastin time (PTT) of 1.5- to 2-times baseline (0.1-0.8 mg/kg/hour); the epoprostenol dose was 2 to 10 ng/kg/min. Additional anti-platelet agents included acetylsalicylic acid, dipyridamole, and clopidogrel in 5 patients each. No bleeding complications occurred. One patient sustained a cerebrovascular infarct on therapy, with subsequent complete recovery. No other complications occurred. Five patients underwent successful transplantation, and 1 patient died of multisystem organ failure. CONCLUSIONS This report provides data on estimated safety and efficacy of bivalirudin and epoprostenol as an AT strategy in pediatric patients on extended VAD support. The short drug half-life and predictable AT response facilitated conversion to standard AT regimens at the time of transplantation (heparin-induced thrombocytopenia-negative patients). These agents should be considered for management of pediatric VAD patients when standard regimens fail.

Utility and Scope of Rapid Prototyping in Patients with Complex Muscular Ventricular Septal Defects or Double-Outlet Right Ventricle: Does it Alter Management Decisions?

Rapid prototyping facilitates comprehension of complex cardiac anatomy. However, determining when this additional information proves instrumental in patient management remains a challenge. We describe our experience with patient-specific anatomic models created using rapid prototyping from various imaging modalities, suggesting their utility in surgical and interventional planning in congenital heart disease (CHD). Virtual and physical 3-dimensional (3D) models were generated from CT or MRI data, using commercially available software for patients with complex muscular ventricular septal defects (CMVSD) and double-outlet right ventricle (DORV). Six patients with complex anatomy and uncertainty of the optimal management strategy were included in this study. The models were subsequently used to guide management decisions, and the outcomes reviewed. 3D models clearly demonstrated the complex intra-cardiac anatomy in all six patients and were utilized to guide management decisions. In the three patients with CMVSD, one underwent successful endovascular device closure following a prior failed attempt at transcatheter closure, and the other two underwent successful primary surgical closure with the aid of 3D models. In all three cases of DORV, the models provided better anatomic delineation and additional information that altered or confirmed the surgical plan. Patient-specific 3D heart models show promise in accurately defining intra-cardiac anatomy in CHD, specifically CMVSD and DORV. We believe these models improve understanding of the complex anatomical spatial relationships in these defects and provide additional insight for pre/intra-interventional management and surgical planning.

Surgical planning for a complex double-outlet right ventricle using 3D printing

Rapid prototyping may be beneficial in properly selected cases of complex congenital heart disease, providing detailed anatomical understanding that helps to guide potential surgical and cardiac catheterization interventions. We present a case of double‐outlet right ventricle, where the decision to obtain a three‐dimensional printed model helped for better understanding of the anatomy, with the additional advantage of surgical simulation in planning the surgical approach and type of surgical repair.

Virtual radiology rounds: adding value in the digital era

BackgroundTo preserve radiology rounds in the changing health care environment, we have introduced virtual radiology rounds, an initiative enabling clinicians to remotely review imaging studies with the radiologist.ObjectiveWe describe our initial experience with virtual radiology rounds and referring provider impressions.Materials and methodsVirtual radiology rounds, a web-based conference, use remote sharing of radiology workstations. Participants discuss imaging studies by speakerphone. Virtual radiology rounds were piloted with the Neonatal Intensive Care Unit (NICU) and the Congenital Cardiovascular Care Unit (CCVCU). Providers completed a survey assessing the perceived impact and overall value of virtual radiology rounds on patient care using a 10-point scale. Pediatric radiologists participating in virtual radiology rounds completed a survey assessing technical, educational and clinical aspects of this methodology.ResultsSixteen providers responded to the survey; 9 NICU and 7 CCVCU staff (physicians, nurse practitioners and fellows). Virtual radiology rounds occurred 4–5 sessions/week with an average of 6.4 studies. Clinicians rated confidence in their own image interpretation with a 7.4 average rating for NICU and 7.5 average rating for CCVCU. Clinicians unanimously rated virtual radiology rounds as adding value. NICU staff preferred virtual radiology rounds to traditional rounds and CCVCU staff supported their new participation in virtual radiology rounds. Four of the five pediatric radiologists participating in virtual radiology rounds responded to the survey reporting virtual radiology rounds to be easy to facilitate (average rating: 9.3), to moderately impact interpretation of imaging studies (average rating: 6), and to provide substantial educational value for radiologists (average rating: 8.3). All pediatric radiologists felt strongly that virtual radiology rounds enable increased integration of the radiologist into the clinical care team (average rating: 8.8).ConclusionVirtual radiology rounds are a viable alternative to radiology rounds enabling improved patient care and education of providers.

Prenatal Diagnosis of a Persistent Fifth Aortic Arch, Pulmonary-to-Systemic type: An Unusual Association with Evolving Aortic Coarctation

Persistent fifth arch (PFA) is a rare anomaly that is often underdiagnosed and missed. Different PFA types that have been reported in the literature are systemic‐to‐systemic type (most common), systemic‐to‐pulmonary artery (PA), and PA‐to‐systemic types. The designations of systemic‐to‐PA or PA‐to‐systemic are based on if the PFA is a source of PA or systemic blood flow, respectively, in the setting of critical proximal obstruction (pulmonary atresia or aortic atresia). This case describes an unusual PFA, which connects the distal PA to distal ascending aorta; however, it is not associated with critical proximal obstruction, and while it appeared to be an incidental finding in early gestation, progressive serial distal obstruction of the left fourth arch was seen to develop. This case highlights that prenatal diagnosis of PFA is possible and that once a diagnosis is made, serial fetal echocardiograms should be performed to evaluate for evolving lesions.

CANDIDACY FOR DEVICE CLOSURE OF COMPLEX MUSCULAR VENTRICULAR SEPTAL DEFECTS: NOVEL APPLICATION OF RAPID PROTOTYPING AND VIRTUAL 3D MODELS DERIVED FCARDIAC CT AND MRI

methods: Virtual and physical 3D models on 3 patients with CMVSD were generated from CT or MRI data, using Mimics, and 3-Matic software. The first patient had history of complicated and unsuccessful prior device closures, with residual shunt. Two physical models, with and without devices in situ were printed (Figure 1A) for this patient. Two virtual models were generated in the other two patients.

Use of Tolvaptan in a Patient With Palliated Congenital Heart Disease.

Heart failure is a common problem in the ever growing population of patients with palliated congenital heart disease. It is frequently complicated by hyponatremia that has been associated with increased morbidity and mortality. Tolvaptan is a vasopressin receptor antagonist that has been effective in improving hyponatremia and congestive symptoms in adults with chronic heart failure. We describe the short-term use of tolvaptan to treat hyponatremic hypervolemia in an adolescent patient with chronic heart failure in the setting of palliated congenital heart disease prior to definitive surgical intervention. In this case, the patient had improvement in hyponatremia and a decrease in body weight, without any adverse effects.

Ubiquitin C-Terminal Hydrolase 1 and Phosphorylated Axonal Neurofilament Heavy Chain in Infants Undergoing Cardiac Surgery: Preliminary Assessment as Potential Biomarkers of Brain Injury

Background: There are no reliable markers to assess brain injury in neonates following cardiac surgery. We examine ubiquitin C-terminal hydrolase 1 (UCHL1) and phosphorylated axonal neurofilament heavy chain (pNF-H), neuronal-specific biomarkers released following axonal and cortical injury, in neonates undergoing cardiac surgery involving cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). Methods: Twenty-six patients younger than three months were prospectively enrolled (CPB only, n = 12 and DHCA, n = 14). Healthy newborns (n = 22) served as the control. Blood samples were collected preoperatively and postoperatively upon intensive care unit admission (hour 0) and subsequently at 12, 24, 36, and 48 hours. Serum was tested for UCHL1 and pNF-H using enzyme-linked immunosorbent assay. Concomitant arterial blood gas, lactate, and cerebral near-infrared spectroscopy (NIRS) monitoring were performed. Results: Ubiquitin C-terminal hydrolase 1 showed a significant rise at 0 hours in the DHCA group compared to baseline (74.9 ± 13.7 pg/mL vs 33.9 ± 37.3 pg/mL, P < .0001). Levels returned to baseline at 12 hours. There was an early rise in UCHL1 at 0 hours in the CPB group, P = .09. Phosphorylated axonal neurofilament heavy chain was decreased at 0 hours in both the CPB and DHCA groups compared to baseline, P = .06. There was no difference between control and baseline levels of UCHL1 (P = .9) or pNF-H (P = .77). Decreased NIRS was observed in the DHCA group at 0 hours (57.3 ± 10.5) versus baseline (64.2 ± 12.3), but not significant (P = .21). There was no correlation between biomarkers and NIRS at 0 hours. Conclusion: A rapid rise in UCHL1 levels was observed in the DHCA group, suggesting that it may be a marker for acute brain injury. Follow-up with neurodevelopmental studies is ongoing.

Complexity of ranolazine and phenytoin use in an infant with long QT syndrome type 3

Introduction Long QT syndrome type 3 (LQT3) results from gain-offunction mutations in the SCN5A gene, which encodes the major cardiac sodium channel, voltage-gated type V alpha subunit (NaV 1.5). Those mutations result in an increase in late sodium channel current, which leads to delayed ventricular repolarization, torsades de pointes (TdP), and sudden death. Traditionally, beta-blockers mexiletine and phenytoin have been the agents of choice in the management of LQT3. Ranolazine is a novel antianginal drug that has been shown to have multichannel blocking effects, including the late sodium channel current (INa,L) and the rapid delayedrectifier potassium current (IKr). The extended-release formulation of ranolazine has a half-life of 7 hours. It has been used in adults with LQT3 ; however, there are currently no published data on its use in the pediatric population. Data have shown that ranolazine is more effective in inhibiting the late vs the peak Naþ current in LQT3 caused by SCN5A mutations. We theorize that use of ranolazine in an infant with LQT3 and persistent TdP refractory to multiple medications would be effective. We report that ranolazine use in infants is very difficult and found that phenytoin was the most effective agent in our patient.

Novel use of an ultrafiltration device as an alternative method for fluid removal in critically ill pediatric patients with cardiac disease: a case series

Fluid overload (FO) is a common complication for pediatric patients in the intensive care unit. When conventional therapy fails, hemodialysis or peritoneal dialysis is classically used for fluid removal. Unfortunately, these therapies are often associated with cardiovascular or respiratory instability. Ultrafiltration, using devices such as the Aquadex™ system (Baxter Healthcare, Deerfield, IL, USA), is an effective tool for fluid removal in adult patients with congestive heart failure. As compared to hemodialysis, ultrafiltration can be performed using smaller catheters, and the extracorporeal volume and minimal blood flow rates are lower. In addition, there is no associated abdominal distension as is seen in peritoneal dialysis. Consequently, ultrafiltration may be better tolerated in critically ill pediatric patients. We present three cases of challenging pediatric patients with FO in the setting of congenital heart disease in whom ultrafiltration using the Aquadex™ system was successfully utilized for fluid removal while cardiorespiratory stability was maintained.