Acute Vasoreactivity Testing during Cardiac Catheterization of Neonates with Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension.

OBJECTIVES: To assess whether better baseline pulmonary hemodynamics or positive acute vasoreactivity testing (AVT) during cardiac catheterization are associated with improved outcomes in infants with bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH). STUDY DESIGN: This retrospective, single-center study included 26 premature neonates with BPD who underwent catheterization to evaluate PH. AVT was assessed with exposure to 100% fractional inspired oxygen with or without inhaled nitric oxide. AVT was positive if the patient met the Barst criteria or increased shunt volume and decreased pulmonary vascular resistance index by >50%. RESULTS: At baseline, the median pulmonary artery mean pressure was 29 mm Hg (IQR, 24-35) and the pulmonary vascular resistance index was 5.3 units*m2 (IQR, 3.5-6.9). Nine patients (35%) had a positive AVT response, which was associated with a decreased risk of death or tracheostomy by 2-year follow-up (hazard ratio, 0.15; P = .02). Baseline pulmonary hemodynamics and the presence of left ventricular diastolic dysfunction were not associated with late outcomes in this cohort. CONCLUSIONS: We found that 35% of infants with BPD who underwent catheterization had positive AVT and that a positive response was associated with better long-term outcomes than nonresponders. AVT better distinguishes higher from lower risk PH in infants with BPD than baseline pulmonary hemodynamics. AVT may aid in the assessment of disease severity and management of BPD-associated PH.

Hemodynamic response to ketamine in children with pulmonary hypertension.

BACKGROUND: The safety of ketamine in children with pulmonary hypertension has been debated because of conflicting results of prior studies in which changes in mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) have been widely variable. The goal of this prospective study was to quantitate the effects of ketamine on pulmonary hemodynamics in a cohort of children with pulmonary hypertension under conditions in which variables such as airway/ventilatory management, FiO(2), and use of vasodilating anesthetics were controlled. METHODS: The IRB approved this study of 34 children undergoing cardiac catheterization for pulmonary hypertension studies. Following anesthetic induction with sevoflurane and tracheal intubation facilitated by the administration of rocuronium 0.7-1 mg·kg(-1) iv, sevoflurane was discontinued and anesthesia was maintained with midazolam 0.1 mg·kg(-1) iv (or 0.5 mg·kg(-1) po preoperatively) and remifentanil iv infusion 0.5-0.7 mcg·kg(-1) ·min(-1). Ventilation was mechanically controlled to maintain PaCO(2) 35-40 mmHg. When endtidal sevoflurane was 0% and FiO(2) was 0.21, baseline heart rate (HR), mean arterial pressure (MAP), mPAP, right atrial pressure (RAP), pulmonary artery occlusion pressure (PAOP), right ventricular end-diastolic pressure (RVEDP), cardiac output, and arterial blood gases were measured, and indexed systemic vascular resistance (SVRI), indexed pulmonary vascular resistance (PVRI), and cardiac index (CI) were calculated. Each child then received a bolus of ketamine 2 mg·kg(-1) infused over 2 min. Measurements and calculations were repeated 2 min after the conclusion of the infusion. RESULTS: The mean (95% CI) increase in mPAP following ketamine was 2 mmHg (0.2, 3.7), which was statistically significant but clinically insignificant. PVRI and PVRI/SVRI did not change significantly. Hemodynamic changes did not differ among subjects with differing severity of pulmonary hypertension or between subjects chronically treated with pulmonary vasodilators or not. CONCLUSION: Ketamine is associated with minimal, clinically insignificant hemodynamic changes in sedated, mechanically ventilated children with pulmonary hypertension.

Diagnostic Utility of Three-Dimensional Rotational Angiography in Congenital Cardiac Catheterization.

We evaluated the diagnostic utility of the three modalities of three-dimensional rotational angiography (3DRA): rotational angiography (RA), multiplanar reformat (MPR) and three-dimensional angiographic reconstruction (3D-R) in pediatric cardiac catheterization. The 3DRA studies were classified by anatomy of interest based on our injection protocol: pulmonary arteries (PA), aorta, cavopulmonary connection (CPC), and others. Retrospective review of 3DRA images by two reviewers for each modality was conducted with grading as inferior, similar, or superior in comparison with the diagnostic quality of fixed-plane angiography (FPA). The percentages of grades for each modality were averaged. Weighted kappa statistic was used to evaluate inter-rater reliability. In total, 114 3DRA studies were performed on 87 patients between August 2010 and March 2012. Median age was 2.7 years (1 day-48.4 years) and median weight 12.1 kg (3.6-106.5 kg). For RA: 79.4 % of the studies were of diagnostic quality and 52.2 % were superior; 3D-R: 82 % were of diagnostic quality and 65.8 % were superior; and MPR: 83.5 % were of diagnostic quality and 63 % were superior. Overall 3DRA technologies (RA, 3D-R, MPR) were of diagnostic quality or better in 111/114 (97.4 %) studies and 103/114 (90.4 %) were judged superior. Most common reasons for inferior grading were limited opacification and metallic artifact. In pediatric cardiac catheterization, 3DRA imaging was of diagnostic quality and frequently provided additional clinically relevant data when compared to FPA.

Percutaneous left atrial decompression in patients supported with extracorporeal membrane oxygenation for cardiac disease.

OBJECTIVES: Left atrial decompression using cardiac catheterization techniques has been described at centers with extracorporeal membrane oxygenation programs. Left atrial decompression can decrease cardiogenic edema, minimize ventricular distension, and allow myocardial recovery. We describe Boston Children's Hospital's experience with percutaneous left atrial decompression techniques, acute outcomes, and clinical impact of left atrial decompression in extracorporeal membrane oxygenation patients. SUBJECTS: Patients supported with extracorporeal membrane oxygenation undergoing percutaneous left atrial decompression were identified and assigned to two groups 1) myocarditis/suspected myocarditis or 2) nonmyocarditis cardiac disease. INTERVENTIONS: Three techniques including vent placement, static balloon dilation, and stent implantation were used. MEASUREMENTS AND MAIN RESULTS: Change in left atrial pressure and severity of pulmonary edema on chest radiography pre and post procedure, impact of timing and technique of left atrial decompression on resolution of left atrial hypertension, and extracorporeal membrane oxygenation survival were evaluated. Furthermore, we evaluated the presence of residual atrial septal defect during follow-up. Percutaneous left atrial decompression was performed in 44 of 419 extracorporeal membrane oxygenation cases (10.5%) and was frequently used for myocarditis (22 of 44 patients; 50%). Techniques included 25 vents, 17 static balloon dilations, and two stents. All techniques were equally successful and significantly reduced left atrial pressure and pulmonary edema. Survival to hospital discharge was not associated with extracorporeal membrane oxygenation duration prior to left atrial decompression, change in left atrial pressure, or technique used. Persistent atrial septal defect was noted in five surviving patients (excluding transplant recipients and deceased), two required closure. CONCLUSIONS: Left atrial decompression can be performed effectively in children on extracorporeal membrane oxygenation using various percutaneous techniques. Reduction in pulmonary venous congestion is usually evident by chest radiography within 48 hours of intervention. Persistent atrial septal defect may require closure at the time of extracorporeal membrane oxygenation decannulation or during long-term follow-up.

The hemodynamic response to dexmedetomidine loading dose in children with and without pulmonary hypertension.

BACKGROUND: Dexmedetomidine, an α-2 receptor agonist, is widely used in children with cardiac disease. Significant hemodynamic responses, including systemic and pulmonary vasoconstriction, have been reported after dexmedetomidine administration. Our primary goal of this prospective, observational study was to quantify the effects of dexmedetomidine initial loading doses on mean pulmonary artery pressure (PAP) in children with and without pulmonary hypertension. METHODS: Subjects were children undergoing cardiac catheterization for either routine surveillance after cardiac transplantation (n = 21) or pulmonary hypertension studies (n = 21). After anesthetic induction with sevoflurane and tracheal intubation, sevoflurane was discontinued and anesthesia was maintained with midazolam 0.1 mg/kg i.v. (or 0.5 mg/kg orally preoperatively) and remifentanil i.v. infusion 0.5 to 0.8 µg/kg/min. Ventilation was mechanically controlled to maintain PCO2 35 to 40 mm Hg. When end-tidal sevoflurane was 0% and fraction of inspired oxygen (FIO2) was 0.21, baseline heart rate, mean arterial blood pressure, PAP, right atrial pressure, pulmonary artery occlusion pressure, right ventricular end-diastolic pressure, cardiac output, and arterial blood gases were measured, and indexed systemic vascular resistance, indexed pulmonary vascular resistance, and cardiac index were calculated. Each subject then received a 10-minute infusion of dexmedetomidine of 1 µg/kg, 0.75 µg/kg, or 0.5 µg/kg. Measurements and calculations were repeated at the conclusion of the infusion. RESULTS: Most hemodynamic responses were similar in children with and without pulmonary hypertension. Heart rate decreased significantly, and mean arterial blood pressure and indexed systemic vascular resistance increased significantly. Cardiac index did not change. A small, statistically significant increase in PAP was observed in transplant patients but not in subjects with pulmonary hypertension. Changes in indexed pulmonary vascular resistance were not significant. CONCLUSION: Dexmedetomidine initial loading doses were associated with significant systemic vasoconstriction and hypertension, but a similar response was not observed in the pulmonary vasculature, even in children with pulmonary hypertension. Dexmedetomidine does not appear to be contraindicated in children with pulmonary hypertension.

Cryo-balloon angioplasty for pulmonary vein stenosis in pediatric patients.

This study sought to determine the safety and effectiveness of cryo-balloon angioplasty (CbA) for pulmonary vein stenosis (PVS) in pediatric patients. Current therapy options for PVS are less than satisfactory due to recurrent progressive restenosis and neointimal proliferation. Catheterization database, hospital records, imaging studies, and pathologic specimens were reviewed for procedural-related and outcomes data in all patients who underwent pulmonary vein (PV) CbA using the Boston Scientific PolarCath Peripheral Dilation System between August 2006 and June 2009. Thirteen patients (19 PVs; median age 13 months [range 3.5 months to 18.5 years] and weight 7.9 kg [range 3.8 to 47.7]) underwent CbA. Mean PVS diameter after CbA increased from 2.19 (± 0.6) to 3.77 (± 1.1) mm (p < 0.001). Mean gradient decreased from 14 (± 7.4) to 4.89 (± 3.2) mm Hg (p < 0.001). Mean stenosis-to-normal vein diameter ratio increased from 0.52 (± 0.15) to 0.89 (± 0.33) (p < 0.001). Eight patients underwent repeat catheterization a mean of 5.6 months (± 3.66) later. Improved PVS diameter was maintained in 2 PVs. Four veins had restenosis but maintained diameters greater than that before initial CbA. In 11 PVs, the diameter decreased from 4.28 (± 1.14) to 2.53 (± 0.9) mm (p = 0.001). Mean gradient increased from 3.55 (± 3.0) to 14.63 (± 9.6) mm Hg (p = 0.011). All vessels underwent repeat intervention with acute relief of PVS. Stroke occurred within 24 h of CbA in 1 patient. CbA of PVS is safe and results in acute relief of stenosis. However, CbA appears minimally effective as the sole therapy in maintaining long-term relief of PVS.

Clinical manifestations and long-term follow-up in pediatric patients living at altitude with isolated pulmonary artery of ductal origin.

This study's aim was to define the clinical manifestations and long-term outcome of pediatric patients living at altitude with isolated pulmonary artery (PA) of ductal origin (IPADO). This was a retrospective cohort study of 17 consecutive cases of IPADO at a single center. All patients lived at modest altitude (median 2050 m [range 1700 m to 3050 m]). Fifteen children (88%) were symptomatic at presentation. High-altitude pulmonary edema was present in 2 patients (12%) at diagnosis, and only 1 patient had episodes of hemoptysis during follow-up. Fourteen patients (82%) demonstrated evidence of pulmonary arterial hypertension (PAH). Among 14 patients with PAH, 11 patients had surgical interventions. PAH resolved in 5 of 11 patients (45%) undergoing surgical rehabilitation. One patient died during follow-up, and 7 patients are receiving oral vasodilator therapies due to residual PAH; 14 patients remained asymptomatic. Our study showed that early intervention in patients with IPADO at modest altitude can potentially rehabilitate the isolated PA and reverse PAH. Whether surgery is indicated for patients with this disorder in the absence of PAH is unknown.

Living at an altitude adversely affects exercise capacity in Fontan patients.

BACKGROUND: Data assessing the effect of altitude on Fontan haemodynamics are limited to experimental models and case reports. Both suggest a detrimental impact. This study describes exercise performance in patients with Fontan circulation and matched controls at a low altitude versus at sea level. We sought to assess the impact of increasing altitude on functional capacity in patients with Fontan palliation. METHODS: A retrospective review of 22 patients at low altitude (1602 metres) and 119 patients at sea level with Fontan circulation, as well as age-, gender-, and altitude-matched controls, underwent maximal cardiopulmonary exercise testing. Linear regression models were created to determine the influence of altitude on differences in exercise variables between Fontan patients and their matched controls. RESULTS: Peak oxygen consumption was 28.4 millilitres per kilogram per minute (72% predicted) for the sea-level cohort and 24.2 millilitres per kilogram per minute (63% predicted) for the moderate altitude cohort. The matched case-control differences for patients at moderate altitude were greater for peak oxygen consumption (-29% against -13%, p = 0.04), anaerobic threshold (-36% against -5%, p = 0.001), and oxygen pulse (-35% against -18%, p = 0.007) when compared with patients living at sea level. When compared to institution-matched controls, the same parameters fell by 3%, 8.9%, and 4.2%, respectively, for each increase of 1000 feet in residential altitude (p = 0.03, p = 0.001, and p = 0.05, respectively). CONCLUSIONS: Patients with Fontan circulation at a higher altitude have impairment in aerobic capacity when compared with patients at sea level. Reduction in exercise capacity is associated with a reduction in stroke volume, likely related to increased pulmonary vascular resistance.

A case of Henoch-Schonlein Purpura with dilated coronary arteries.

BACKGROUND: Henoch-Schonlein Purpura (HSP) is one of the most common vasculitides of childhood, with 10-20 cases per 100,000 children. It frequently occurs following an infectious trigger and involves IgA and C3 deposition in small vessel walls. HSP is characterized by palpable purpura plus IgA deposition on biopsy, arthritis/arthralgia, renal involvement (hematuria and/or proteinuria), and/or abdominal pain. It is not generally recognized as a cause of dilated coronary arteries. CASE PRESENTATION: We describe the first reported case of HSP presenting with dilated coronary arteries. This patient is a nine-year-old previously healthy Caucasian male who presented with 1 week of petechiae on his lower legs, knee and ankle arthritis, and abdominal pain without fever, consistent with HSP. An echocardiogram revealed coronary dilation, including the left main (5.32 mm, Z score + 4.25) and left anterior descending (LAD) (3.51 mm, Z score + 2.64) coronary arteries. He received high dose aspirin, IVIG, and infliximab with normalization of the LAD. Skin biopsy revealed leukocytoclastic vasculitis with positive IgA staining. He was Rhinovirus/Enterovirus positive with Group A Streptococcus on throat culture. CONCLUSION: Cardiac findings, while rare, can exist in HSP. Coronary dilation appeared to respond to our hospital protocol's Kawasaki Disease (KD) therapy, possibly indicating an overlap in HSP and KD pathophysiology. This case, along with prior reports of dilated coronaries in systemic juvenile idiopathic arthritis (SJIA), highlights the importance of considering other sources of systemic inflammation, in addition to KD, when coronary dilation is identified. The appropriate therapy, follow-up, and prognosis for our patient are not clear, as further studies are needed to determine the natural course of these findings.

Pulmonary interstitial glycogenosis: Diagnostic evaluation and clinical course.

OBJECTIVES: We sought to describe the phenotype for patients with P.I.G. including presentation, evaluation, cardiac co-morbidities, high resolution computed tomography findings, and outcomes. METHODS: With institutional review board approval, we performed a retrospective review of patients with biopsy-proven P.I.G. Biopsies, high resolution chest computed tomography, and cardiac evaluations were reviewed and characterized by experts in each field. RESULTS: Sixty-two percent of the patients were male. The median gestational age was 37 weeks (range 27-40). The median age at biopsy was 1.6 months (range 0.3-6 months). Structural heart disease was present in 63% of patients. Pulmonary hypertension (diagnosed by echocardiogram and/or cardiac catheterization) was noted in 38% of patients. Alveolar simplification was present in 79% of patients. Fifty percent of available biopsies revealed patchy disease. An increase in age at biopsy was associated with patchy (vs diffuse) disease. Ninety-two percent of patients were treated with systemic corticosteroids. Median age at last follow-up was 1234 days with a range of 37 days to 15 years. At the time of last follow-up, 12 patients were off all support, eight were on supplemental oxygen, two were mechanically ventilated, one underwent lung transplantation, and one died. CT findings commonly included ground glass opacities (86%) and cystic change (50%). CONCLUSIONS: The P.I.G. phenotype has not been comprehensively described, and poor recognition and misconceptions about P.I.G. persist. P.I.G. is a disease that presents in early infancy, requires significant medical intervention, and frequently is seen in association with alveolar simplification and/or cardiovascular disease. CT findings include ground glass opacities and cysts. Patients should be monitored for pulmonary hypertension. Without life-threatening comorbidities, many patients do well over time, although respiratory symptoms may persist into adolescence.

Device closure of secundum atrial septal defects in children <15 kg: complication rates and indications for referral.

OBJECTIVES: This study sought to determine institutional complication rates in a previously underreported patient population and discuss referral indications. BACKGROUND: There has been a trend over the years for referral of younger and smaller patients for "elective" closure of atrial septal defects (ASD). In general, the risks associated with ASD device closure are believed and reported to be relatively low. Complication rates in this group of smaller patients are not well described in the literature for either percutaneous or surgical approaches. METHODS: Retrospective review of all patients who underwent elective transcatheter closure of secundum ASD between March 2000 and April 2010. We excluded all children >15 kg, as well as those with complex congenital heart defects. Major and minor complications were predefined and indications for referral were evaluated. RESULTS: We identified 128 patients meeting criteria with a median procedural age of 1.92 years (3 months to 4.92 years), and median weight of 10.8 kg (4.3 to 14.9 kb). There were 7 major (5.5%) and 12 minor (9.4%) complications. Nearly two-thirds of referrals were for right heart enlargement or poor growth. Rate of resolution of residual shunt was 99%. When compared with age, there was no difference in the rate of resolution of right heart enlargement. No clinically significant improvement in growth was observed. CONCLUSIONS: Transcatheter ASD closure in small children is highly successful, but with an increase in previously perceived complication rates. In small, asymptomatic patients, deferral of closure until the historically established timeline of around 4 to 5 years of age should be strongly considered.

Deciding without data.

INTRODUCTION: Physician decisions drive most of the increases in health care expenditures, yet virtually no published literature has sought to understand the types of evidence used by physicians as they make decisions in real time. METHODS: Ten pediatric cardiologists recorded every clinically significant decision made during procedures, test interpretation, or delivery of inpatient and outpatient care during 5 full days and 5 half days of care delivery. The basis for each decision was assigned to one of 10 predetermined categories, ranging from arbitrary and anecdotal, to various qualities of published studies, to parental preference and avoiding a lawsuit. RESULTS: During the 7.5 days, 1188 decisions (158/day) were made. Almost 80% of decisions were deemed by the physicians to have no basis in any prior published data and fewer than 3% of decisions were based on a study specific to the question at hand. CONCLUSIONS: In this pilot study, physicians were unable to cite a formal evidence source for most of their real-time clinical decision making, including those that consumed medical resources. Novel approaches to building an evidence base produced from real-time clinical decisions may be essential for health care reform based on data.

Predicting recovery: successful explant of a ventricular assist device in a child with dilated cardiomyopathy.

A previously healthy, 13-year-old girl presented with new-onset dilated cardiomyopathy, and is placed on a left ventricular assist device (VAD). Herein we describe a unique VAD weaning protocol used to determine the timing and feasibility of a VAD explant.

Case report: an infant with congenital junctional ectopic tachycardia requiring extracorporeal mechanical oxygenation.

PURPOSE OF REVIEW: A case report of an infant with hemodynamic compromise and impending collapse due to congenital junctional ectopic tachycardia. Medical therapy was maximized and he required the rapid initiation of extracorporeal life support, in order to achieve hemodynamic stability. RECENT FINDINGS: This case report briefly reviews the presentation and treatment options for congenital junctional ectopic tachycardia, as well as the indications for initiation of mechanical support for this potentially lethal condition. SUMMARY: Congenital junctional ectopic tachycardia is a rare though often fatal arrhythmia of the newborn or infant. Medical treatment options may be limited, or may require time to attain efficacy. Despite aggressive escalation of antiarrhythmic therapy, mechanical support in the form of extracorporeal mechanical oxygenation is a viable option, until the arrhythmia is well controlled and the myocardium recovers function.