Aliessa P. Barnes

Management of Single‐Ventricle Patients With Berlin Heart EXCOR Ventricular Assist Device: Single‐Center Experience

There are minimal data regarding chronic management of single-ventricle ventricular assist device (VAD) patients. This study aims to describe our centers multidisciplinary team management of single-ventricle patients supported long term with the Berlin Heart EXCOR Pediatric VAD. Patient #1 was a 4-year-old with double-outlet right ventricle with aortic atresia, L-looped ventricles, and heart block who developed heart failure 1 year after Fontan. She initially required extracorporeal membrane oxygenation support and was transitioned to Berlin Heart systemic VAD. She was supported for 363 days (cardiac intensive care unit [CICU] 335 days, floor 28 days). The postoperative course was complicated by intermittent infection including methicillin-resistant Staphylococcus aureus, intermittent hepatic and renal insufficiencies, and transient antithrombin, protein C, and protein S deficiencies resulting in multiple thrombi. She had a total of five pump changes over 10 months. Long-term medical management included anticoagulation with enoxaparin, platelet inhibition with aspirin and dipyridamole, and antibiotic prophylaxis using trimethoprim/sulfamethoxazole. She developed sepsis of unknown etiology and subsequently died from multiorgan failure. Patient #2 was a 4-year-old with hypoplastic left heart syndrome who developed heart failure 2 years after bidirectional Glenn shunt. At systemic VAD implantation, he was intubated with renal insufficiency. Post-VAD implantation, his renal insufficiency resolved, and he was successfully extubated to daytime nasal cannula and biphasic positive airway pressure at night. He was supported for 270 days (CICU 143 days, floor 127 days). The pump was upsized to a 50-mL pump in May 2011 for increased central venous pressures (29 mm Hg). Long-term medical management included anticoagulation with warfarin and single-agent platelet inhibition using dipyridamole due to aspirin resistance. He developed increased work of breathing requiring intubation, significant anasarca, and bleeding from the endotracheal tube. The family elected to withdraw support. Although both patients died prior to heart transplantation, a consistent specialized multidisciplinary team approach to the medical care of our VAD patients, consisting of cardiothoracic surgeons, heart transplant team, hematologists, pharmacists, infectious disease physicians, psychiatrists, specialty trained bedside nursing, and nurse practitioners, allowed us to manage these patients long term while awaiting heart transplantation.

Lessons Learned from Preparticipation Cardiovascular Screening in a State Funded Program

In 2007, the Texas legislature appropriated money for a pilot study to evaluate cardiovascular screening of student athletes to identify those who might be at risk of sudden death using a questionnaire, physical examination, electrocardiography, and limited echocardiography. We sought to determine (1) the feasibility of a state-wide cardiovascular screening program, (2) the ability to reliably identify at-risk subjects, and (3) problems in implementing screening state wide. The data were analyzed using established pediatric electrocardiographic and echocardiographic criteria. Positive results were confirmed by a blinded reviewer. In 31 venues (2,506 students), the electrocardiographic findings met the criteria for cardiovascular disease in 57 (2.3%), with 33 changes suggestive of hypertrophic cardiomyopathy, 14 with long QT syndrome, 7 with Wolff-Parkinson-White syndrome, and 3 with potential ischemic findings related to a coronary anomaly. Of the 2,051 echocardiograms, 11 had findings concerning for disease (9 with hypertrophic cardiomyopathy and 1 with dilated cardiomyopathy). In patients with electrocardiographic findings consistent with hypertrophic cardiomyopathy, the limited echocardiograms were normal in 24 of 33. Of the 33 who remained at risk of sudden death on the electrocardiogram or echocardiogram, 25 (65.8%) pursued the recommended evaluation, which confirmed long QT syndrome in 4, Wolff-Parkinson-White syndrome in 7, and dilated cardiomyopathy in 1. The interobserver agreement was 100% for electrocardiography and 79% for echocardiography. The questionnaire identified 895 (35% of the total) potentially at-risk students, with disease confirmed in 11 (1.23%). In conclusion, in this large state-funded project, electrocardiographic and echocardiographic screening identified 11 of 2,506 patients potentially at risk of cardiovascular disease. The questionnaire was of limited value and had a large number of false-positive results. Interobserver variation was significant for echocardiography and might create problems with limited echocardiographic screening. Finally, many subjects with abnormal screening results declined a follow-up evaluation.

High-Sensitivity Cardiac Troponin I Assay to Screen for Acute Rejection in Patients With Heart Transplant

Background—A noninvasive biomarker that could accurately diagnose acute rejection (AR) in heart transplant recipients could obviate the need for surveillance endomyocardial biopsies. We assessed the performance metrics of a novel high-sensitivity cardiac troponin I (cTnI) assay for this purpose. Methods and Results—Stored serum samples were retrospectively matched to endomyocardial biopsies in 98 cardiac transplant recipients, who survived ≥3 months after transplant. AR was defined as International Society for Heart and Lung Transplantation grade 2R or higher cellular rejection, acellular rejection, or allograft dysfunction of uncertain pathogenesis, leading to treatment for presumed rejection. cTnI was measured with a high-sensitivity assay (Abbott Diagnostics, Abbott Park, IL). Cross-sectional analyses determined the association of cTnI concentrations with rejection and International Society for Heart and Lung Transplantation grade and the performance metrics of cTnI for the detection of AR. Among 98 subjects, 37% had ≥1 rejection episode. cTnI was measured in 418 serum samples, including 35 paired to a rejection episode. cTnI concentrations were significantly higher in rejection versus nonrejection samples (median, 57.1 versus 10.2 ng/L; P<0.0001) and increased in a graded manner with higher biopsy scores (Ptrend<0.0001). The c-statistic to discriminate AR was 0.82 (95% confidence interval, 0.76–0.88). Using a cut point of 15 ng/L, sensitivity was 94%, specificity 60%, positive predictive value 18%, and negative predictive value 99%. Conclusions—A high-sensitivity cTnI assay seems useful to rule out AR in cardiac transplant recipients. If validated in prospective studies, a strategy of serial monitoring with a high-sensitivity cTnI assay may offer a low-cost noninvasive strategy for rejection surveillance.

A Sensitive Cardiac Troponin I Assay to Screen for Acute Rejection in Heart Transplant Patients

Background—A noninvasive biomarker that could accurately diagnose acute rejection (AR) in heart transplant recipients could obviate the need for surveillance endomyocardial biopsies. We assessed the performance metrics of a novel high-sensitivity cardiac troponin I (cTnI) assay for this purpose. Methods and Results—Stored serum samples were retrospectively matched to endomyocardial biopsies in 98 cardiac transplant recipients, who survived ≥3 months after transplant. AR was defined as International Society for Heart and Lung Transplantation grade 2R or higher cellular rejection, acellular rejection, or allograft dysfunction of uncertain pathogenesis, leading to treatment for presumed rejection. cTnI was measured with a high-sensitivity assay (Abbott Diagnostics, Abbott Park, IL). Cross-sectional analyses determined the association of cTnI concentrations with rejection and International Society for Heart and Lung Transplantation grade and the performance metrics of cTnI for the detection of AR. Among 98 subjects, 37% had ≥1 rejection episode. cTnI was measured in 418 serum samples, including 35 paired to a rejection episode. cTnI concentrations were significantly higher in rejection versus nonrejection samples (median, 57.1 versus 10.2 ng/L; P<0.0001) and increased in a graded manner with higher biopsy scores (Ptrend<0.0001). The c-statistic to discriminate AR was 0.82 (95% confidence interval, 0.76–0.88). Using a cut point of 15 ng/L, sensitivity was 94%, specificity 60%, positive predictive value 18%, and negative predictive value 99%. Conclusions—A high-sensitivity cTnI assay seems useful to rule out AR in cardiac transplant recipients. If validated in prospective studies, a strategy of serial monitoring with a high-sensitivity cTnI assay may offer a low-cost noninvasive strategy for rejection surveillance.

Use of a highly sensitive assay for cardiac troponin T and N-terminal pro-brain natriuretic peptide to diagnose acute rejection in pediatric cardiac transplant recipients.

BACKGROUND Biomarkers have been proposed to augment or replace endomyocardial biopsy (EMB) to diagnose acute transplant rejection (AR). A new, highly sensitive assay for troponin T detects levels of cardiac troponin T (cTnT) 10- to 100-fold lower than standard assays but has not been investigated in transplant patients. N-terminal pro-brain natriuretic peptide (NT-proBNP) has not been evaluated in pediatric transplant patients. The purpose of this pilot study was to evaluate the association of cTnT and NT-proBNP with AR in pediatric cardiac transplant patients. METHODS Plasma was obtained at the time of EMB from pediatric patients ≥ 1 year old. N-terminal pro-brain natriuretic peptide was measured in fresh plasma at the time of biopsy, and cTnT was measured from frozen, stored samples using the highly sensitive assay for troponin T. Biomarker data were correlated with EMB results. Cellular AR was defined as an International Society for Heart and Lung Transplantation biopsy score of grade ≥ 2R. RESULTS Fifty-three blood samples were obtained from 42 patients (mean age 11 years). Seven episodes of AR occurred in 5 patients. Biopsies with vs without AR were associated with higher cTnT (median [interquartile range {IQR}] 66 [45-139] vs 7 [2-13] pg/mL, P = .001) and NT-proBNP (median [IQR] 11,169 [280-23,317] vs 334 [160-650] pg/mL, P < .01). After successful treatment of AR in 5 patients, cTnT fell markedly (median [IQR] 53.5 [44.8-66.5] to 10.7 [1.5-16.4], P = .05). CONCLUSION In this pilot study, we found marked elevation of cTnT and NT-proBNP among children with AR. Moreover, reduction in cTnT levels after treatment paralleled improvement in EMB results. If these findings are confirmed in larger prospective studies, monitoring with these biomarkers may obviate surveillance EMB.

Partial anomalous pulmonary venous return in a patient with turner syndrome

A 2-year old with a history of Turner Syndrome (XO), hypoplastic kidneys, hydronephrosis and gonadal dysgenesis had an abnormal screening echocardiogram which showed the following: bicuspid aortic valve, bilateral superior vena cava (SVC), dilated right atrium and ventricle, intact atrial septum and partial anomalous pulmonary venous return (PAPVR). By echocardiogram, the lower right and left pulmonary veins drained normally to the left atrium, the right upper pulmonary vein to the right SVC and the left upper pulmonary vein could not be identified. By cardiac magnetic resonance imaging (MRI), the findings agreed with echocardiogram with the exception that both the right upper and middle veins connected and drained anomalously to the right SVC (above the right pulmonary artery) and the unique finding of a left upper and lingular pulmonary veins draining directly to the left SVC to the coronary sinus. Of note a tiny bridging vein was present and a left azygous vein was not identified on MRI. In addition, an aortopulmonary collateral from the abdominal aorta to the right lung was identified by cardiac MRI. By cardiac catheterization, she underwent successful embolization of her aortopulmonary collateral and her pulmonary venous anatomy was confirmed. She underwent successful surgical repair of her defect and all findings were confirmed at the time of surgery. The PAPVR involving both the right and left sided pulmonary veins have been described, but the left sided veins usually drain into the innominate vein directly or via a vertical vein [1, 2]. This is the only report, to our knowledge, that has direct connection of the pulmonary veins to the left SVC draining inferiorly to the coronary sinus (Figs. 1, 2). Although bicuspid aortic valve and coarctation of the aorta are common cardiac lesions in patients with Turner Syndrome, there are multiple reports of anomalous pulmonary venous return with intact atrial septum [3, 4]. An adult study using cardiac MRI in Turner syndrome showed