Angiographic tool to detect pulmonary arteriovenous malformations in single ventricle physiology.

OBJECTIVE: Individuals with single ventricle physiology who are palliated with superior cavopulmonary anastomosis (Glenn surgery) may develop pulmonary arteriovenous malformations. The traditional tools for pulmonary arteriovenous malformation diagnosis are often of limited diagnostic utility in this patient population. We sought to measure the pulmonary capillary transit time to determine its value as a tool to identify pulmonary arteriovenous malformations in patients with single ventricle physiology. METHODS: We defined the angiographic pulmonary capillary transit time as the number of cardiac cycles required for transit of contrast from the distal pulmonary arteries to the pulmonary veins. Patients were retrospectively recruited from a single quaternary North American paediatric centre, and angiographic and clinical data were reviewed. Pulmonary capillary transit time was calculated in 20 control patients and compared to 20 single ventricle patients at the pre-Glenn, Glenn, and Fontan surgical stages (which were compared with a linear-mixed model). Correlation (Pearson) between pulmonary capillary transit time and haemodynamic and injection parameters was assessed using angiograms from 84 Glenn patients. Five independent observers calculated pulmonary capillary transit time to measure reproducibility (intraclass correlation coefficient). RESULTS: Mean pulmonary capillary transit time was 3.3 cardiac cycles in the control population, and 3.5, 2.4, and 3.5 in the pre-Glenn, Glenn, and Fontan stages, respectively. Pulmonary capillary transit time in the Glenn population did not correlate with injection conditions. Intraclass correlation coefficient was 0.87. CONCLUSIONS: Pulmonary angiography can be used to calculate the pulmonary capillary transit time, which is reproducible between observers. Pulmonary capillary transit time accelerates in the Glenn stage, correlating with absence of direct hepatopulmonary venous flow.

Angiographic Tool to Detect Pulmonary Arteriovenous Malformations in Single Ventricle Physiology.

Background: Individuals with single ventricle physiology who are palliated with superior cavopulmonary anastomosis (Glenn surgery) may develop pulmonary arteriovenous malformations (PAVMs). The traditional tools for PAVM diagnosis are often of limited diagnostic utility in this patient population. We sought to measure the pulmonary capillary transit time (PCTT) to determine its value as a tool to identify PAVMs in patients with single ventricle physiology. Methods: We defined the angiographic PCTT as the number of cardiac cycles required for transit of contrast from the distal pulmonary arteries to the pulmonary veins. Patients were retrospectively recruited from a single quaternary North American pediatric center, and angiographic and clinical data was reviewed. PCTT was calculated in 20 control patients and compared to 20 single ventricle patients at the pre-Glenn, Glenn, and Fontan surgical stages (which were compared with a linear-mixed model). Correlation (Pearson) between PCTT and hemodynamic and injection parameters was assessed using 84 Glenn angiograms. Five independent observers calculated PCTT to measure reproducibility (intra-class correlation coefficient). Results: Mean PCTT was 3.3 cardiac cycles in the control population, and 3.5, 2.4, and 3.5 in the pre-Glenn, Glenn, and Fontan stages, respectively. PCTT in the Glenn population did not correlate with injection conditions. Intraclass correlation coefficient was 0.87. Conclusions: Pulmonary angiography can be used to calculate the pulmonary capillary transit time, which is reproducible between observers. PCTT accelerates in the Glenn stage, correlating with absence of direct hepatopulmonary venous flow.

Diagnosis and Management of Congenital Coronary Artery Fistulas in Infants and Children.

PURPOSE OF REVIEW: Coronary artery fistulas (CAFs) are rare coronary anomalies that most often occur as congenital malformations in children. Although most children with CAFs are asymptomatic at the time of diagnosis, some present with symptoms of congestive heart failure in the setting of large left-to-right shunts. Others may develop additional complications including coronary artery ectasia and coronary thrombosis. Surgical and transcatheter closure techniques have been previously described. This review presents the classifications of CAFs in children and the short and long-term outcomes of CAF closure in children in the reported literature. We also summarize previously-reported angiographic findings and post-treatment remodeling characteristics in pediatric patients. RECENT FINDINGS: With advancements in cross-sectional imaging technologies, anatomic delineation of CAFs via these modalities has become crucial in procedural planning. Recent reports of surgical and transcatheter closure of CAFs in children have reported good procedural success and low rates of short-term morbidity and mortality. Distal-type CAFs have elevated risk for long-term sequelae post-closure compared to proximal-type CAFs. A recent report of a multi-institutional cohort also describes post-closure remodeling classifications which may predict long-term outcomes in these patients as well as guide individualized anticoagulation management. Invasive closure of significant CAFs via surgical or transcatheter techniques is feasible and safe in most children with good short and intermediate-term outcomes. However, close clinical and imaging follow-up is required to monitor for late complications even after successful closure. Antiplatelet and anticoagulation regimens remain important aspects of post-closure management, but the necessary intensity and duration of such therapy remains unknown.

Transcatheter Device Therapy and the Integration of Advanced Imaging in Congenital Heart Disease.

Transcatheter device intervention is now offered as first line therapy for many congenital heart defects (CHD) which were traditionally treated with cardiac surgery. While off-label use of devices is common and appropriate, a growing number of devices are now specifically designed and approved for use in CHD. Advanced imaging is now an integral part of interventional procedures including pre-procedure planning, intra-procedural guidance, and post-procedure monitoring. There is robust societal and industrial support for research and development of CHD-specific devices, and the regulatory framework at the national and international level is patient friendly. It is against this backdrop that we review transcatheter implantable devices for CHD, the role and integration of advanced imaging, and explore the current regulatory framework for device approval.

Role of Cross-Sectional Imaging in Pediatric Interventional Cardiac Catheterization.

Management of congenital heart disease (CHD) has recently increased utilization of cross-sectional imaging to plan percutaneous interventions. Cardiac computed tomography (CT) and cardiac magnetic resonance (CMR) imaging have become indispensable tools for pre-procedural planning prior to intervention in the pediatric cardiac catheterization lab. In this article, we review several common indications for referral and the impact of cross-sectional imaging on procedural planning, success, and patient surveillance.

Pre-procedural CT imaging aids neonatal PDA stenting for ductal-dependent pulmonary blood flow with reduction in overall procedural morbidity.

Patent ductus arteriosus stenting for ductal-dependent pulmonary blood flow is a technically challenging neonatal procedure to maintain a stable pulmonary circulation. Pre-procedural computed tomography imaging aids in outlining ductal origin, insertion, size, course and curvature. Computed tomography imaging may add value to procedural outcomes and reduce overall procedural morbidity in neonatal patent ductus arteriosus stenting. We conducted a single centre retrospective chart review of neonates with ductal-dependent pulmonary blood flow who underwent patent ductus arteriosus stenting between January 1, 2014 and June 31, 2020. We compared patients variables between patients who underwent pre-procedural computed tomography imaging to those who did not. A total of 64 patients were referred for patent ductus arteriosus stenting with 33 (52%) obtaining pre-procedural computed tomography imaging. Average age [19 days; range 1-242 days (p = 0.85)] and weight [3.3 kg (range 2.2-6.0 kg; p = 0.19)] was not significantly different between the groups. A diagnosis of pulmonary atresia was made in 42 out of 64 (66%) patients prior to patent ductus arteriosus stenting. The cohort with pre-intervention computed tomography imaging had a significant reduction in the total number of access sites (1.2 versus 1.5; p = 0.03), contrast needed (5.9 versus 8.2 ml/kg; p = 0.008), fluoroscopy (20.7 versus 38.8 minutes; p = 0.02) and procedural time (83.4-128.4 minutes; p = 0.002) for the intervention. There was no significant difference in radiation burden between the groups (p = 0.35). Pre-procedural computed tomography imaging adds value by aiding interventional planning for neonatal patent ductus arteriosus stenting. A statistically significant reduction in the number of access sites, contrast exposure, as well as fluoroscopic and procedural time was noted without significantly increasing the cumulative radiation burden.

Comparison of the investigational device exemption and post-approval trials of the Melody transcatheter pulmonary valve.

OBJECTIVE: We compared 5-year outcomes of transcatheter pulmonary valve (TPV) replacement with the Melody TPV in the post-approval study (PAS) and the investigational device exemption (IDE) trial. BACKGROUND: As a condition of approval of the Melody TPV after the IDE trial, the Food and Drug Administration required that a PAS be conducted to evaluate outcomes of TPV replacement in a "real-world" environment. The 5-year outcomes of the PAS have not been published, and the IDE and PAS trials have not been compared. METHODS: The cohorts comprised all patients catheterized and implanted at 5 IDE sites and 10 PAS sites. Differences in trial protocols were detailed. Time-related outcomes and valve-related adverse events were compared between the two trials with Kaplan-Meier curves and log-rank testing. RESULTS: 167 patients (median age, 19 years) were catheterized and 150 underwent TPV replacement in the IDE trial; 121 were catheterized (median age, 17 years) and 100 implanted in the PAS. Freedom from hemodynamic dysfunction (p = .61) or any reintervention (p = .74) over time did not differ between trials. Freedom from stent fracture (p = .003) and transcatheter reintervention (p = .010) were longer in PAS, whereas freedom from explant (p = .020) and TPV endocarditis (p = .007) were shorter. Clinically important adverse events (AEs) were reported in 14% of PAS and 7.2% of IDE patients (p = .056); the incidence of any particular event was low in both. CONCLUSIONS: Hemodynamic and time-related outcomes in the PAS and IDE trials were generally similar, confirming the effectiveness of the Melody TPV with real-world providers. There were few significant complications and limited power to identify important differences in AEs. The lack of major differences in outcomes between the two studies questions the usefulness of mandated costly post-approval studies as part of the regulatory process for Class III medical devices.

ACCAPA: anomalous circumflex coronary artery origin from pulmonary artery.

Anomalous circumflex coronary artery origin from pulmonary artery is a very rare congenital heart disease. Misdiagnosis of this condition may lead to inadequate myocardial protection during cardiopulmonary bypass surgery.

3D advanced imaging overlay with rapid registration in CHD to reduce radiation and assist cardiac catheterisation interventions.

Novel commercially available software has enabled registration of both CT and MRI images to rapidly fuse with X-ray fluoroscopic imaging. We describe our initial experience performing cardiac catheterisations with the guidance of 3D imaging overlay using the VesselNavigator system (Philips Healthcare, Best, NL). A total of 33 patients with CHD were included in our study. Demographic, advanced imaging, and catheterisation data were collected between 1 December, 2016 and 31 January, 2019. We report successful use of this technology in both diagnostic and interventional cases such as placing stents and percutaneous valves, performing angioplasties, occlusion of collaterals, and guidance for lymphatic interventions. In addition, radiation exposure was markedly decreased when comparing our 10-15-year-old coarctation of the aorta stent angioplasty cohort to cases without the use of overlay technology and the most recently published national radiation dose benchmarks. No complications were encountered due to the application of overlay technology. 3D CT or MRI overlay for CHD intervention with rapid registration is feasible and aids decisions regarding access and planned angiographic angles. Operators found intraprocedural overlay fusion registration using placed vessel guidewires to be more accurate than attempts using bony structures.

Invasive Hemodynamics of Adult Congenital Heart Disease: From Shunts to Coarctation.

Adults with congenital heart disease are a growing population with increasingly more complex disease, in large part due to improvements in delivery of care to the pediatric population. Cardiac catheterization is an integral component of diagnosis and management in these patients. Careful attention to detail and a thorough understanding of intracardiac hemodynamics are critical to performing complete diagnostic evaluations. This article outlines the most commonly encountered lesions with guidelines for invasive assessment to help guide further therapy.

Initial Experience With the Pediatric Impella Device: A Feasibility Study in a Porcine Model.

OBJECTIVE: This study's objective was to evaluate insertion techniques and device fit of the pediatric version of the Impella ventricular assist device in swine which had similar sized carotids and left ventricles (LVs) as children weighing 10-20 kg. BACKGROUND: Options for minimally invasive circulatory support in children are limited. A modified device based on the current Impella 2.5 platform was created in an effort to provide minimally invasive circulatory support for children. METHODS: Animal studies (n = 10) were performed to determine technical feasibility of device implant via the right common carotid artery (RCCA) in swine with a carotid and LV size similar to children with a BSA < 1 m2 and weight 10-20 kg. The RCCA diameter was measured on pre-implant ultrasound and the LV length was measured at necropsy. The animals were supported for 4 hr and the device explanted. Blood samples and post-explant necropsy was performed to evaluate for device related complications. RESULTS: All animals underwent successful device insertion. Mean carotid artery diameter by ultrasound was 3.5 ± 0.3 mm. There was no LV or aortic/mitral valve damage with a minimum LV length of 5.4 cm. CONCLUSIONS: Minimally invasive circulatory support is needed in small children. Limitations are primarily related to vessel and chamber size. The Impella Pediatric catheter was safely and successfully implanted in carotid arteries similar in size to children weighing 10-20 kg with minimal complications. © 2016 Wiley Periodicals, Inc.

One-year follow-up of the Melody transcatheter pulmonary valve multicenter post-approval study.

OBJECTIVES: This study sought to confirm that the short-term hemodynamic effectiveness of the Melody transcatheter pulmonary valve (TPV) (Medtronic, Inc., Minneapolis, Minnesota) achieved by real-world providers is equivalent to the historical results established in the initial 5-center Investigational Device Exemption trial. BACKGROUND: TPV replacement has been used to treat right ventricular outflow tract (RVOT) conduit dysfunction for >10 years. The Melody TPV received U.S. Food and Drug Administration approval in 2010 as a Humanitarian Use Device. METHODS: Patients with dysfunctional RVOT conduits were entered in this prospective, nonrandomized study at 10 centers. The primary endpoint was acceptable hemodynamic function at 6 months post-implantation, defined as a composite of RVOT echocardiographic mean gradient ≤30 mm Hg, pulmonary regurgitation less than moderate as measured by echocardiography, and freedom from conduit reintervention and reoperation. RESULTS: Cardiac catheterization was performed in 120 patients for potential implantation of the Melody TPV; of these, 100 patients were implanted, with a 98.0% procedural success rate. There were no procedure-related deaths. Acceptable hemodynamic function at 6 months was achieved in 96.7% of patients with evaluable data (87.9% of the entire implanted cohort), with results maintained through 1 year. No patient had moderate or severe pulmonary regurgitation after implantation. No patient required catheter reintervention in the first year after implantation, and 2 patients required reoperation for conduit replacement. The rate of freedom from TPV dysfunction was 96.9% at 1 year. CONCLUSIONS: This first prospective, real-world experience with the Melody TPV in the United States demonstrates continued high procedural success, excellent short-term TPV function, and low reintervention and reoperation rates at 1 year. (Melody Transcatheter Pulmonary Valve Post-Approval Study; NCT01186692).

Simultaneous stent implantation to treat bifurcation stenoses in the pulmonary arteries: Initial results and long-term follow up.

BACKGROUND: Balloon angioplasty of bifurcating pulmonary artery (PA) stenoses is often inadequate, and stent treatment often requires simultaneous implantation of two stents. This study evaluates initial results and long-term follow up of transcatheter stent placement in bifurcating PAs. METHODS: This is a retrospective review of patients (pts) who had bifurcating PA stents placed in main and lobar branches from 1993 to 2007. RESULTS: Forty-nine pts had bifurcating PA stents placed at a median age of 10.9 years (range 1-43 years). The mean minimum vessel diameter increased from 5.7 +/- 2.5 mm to 11.0 +/- 3.6 mm (P < 0.001), the mean gradient across the stenoses decreased from 37.0 +/- 26.9 to 9.2 +/- 13 mm Hg (P < 0.001), whereas the mean RV:FA ratio decreased from 0.76 +/- 0.29 to 0.53 +/- 0.24 (P < 0.001). There was one death due to severe pulmonary hemorrhage. F/U data were available in 38 pts (mean duration 6.3 +/- 4.1 years, range 1.2-13.1 years). Thirty pts underwent repeat catheterizations (mean 2.3 +/- 2.2 years poststent), with 26 requiring further interventions: Fifteen had balloon angioplasty alone and 11 had additional stents placed. There were no complications at f/u catheterization. Six pts underwent further palliative surgeries, although none for repair of branch PA stenoses. CONCLUSIONS: Simultaneous transcatheter placement of bifurcating PA stents provides immediate gradient relief of bifurcating stenoses in the proximal or lobar branch PAs and reduces RV systolic pressure. Further interventions can be safely performed in future procedures, and the presence of stents does not complicate future surgeries.

Aspirin resistance in children with heart disease at risk for thromboembolism: prevalence and possible mechanisms.

Aspirin is used to prevent thromboembolism in children with heart disease without evidence supporting its efficacy. Studies in adults report a 5%-51% prevalence of aspirin resistance, yet the mechanisms involved are poorly understood. Our aims were to determine its prevalence in these children and to explore its possible mechanisms. One hundred twenty-three cardiac patients routinely receiving aspirin were prospectively enrolled. Platelet function was measured by Platelet Function Analyzer (PFA)-100 using epinephrine and adenosine diphosphate (ADP) agonists. Aspirin resistance was defined as failure to prolong the epinephrine closure time following aspirin administration. Urine levels of 11-dehydro-thromboxane B(2) (11-dTXB(2)) were measured to determine inhibition of the cyclo-oxygenase pathway. The prevalence of aspirin resistance was 26%. Median ADP closure time was shorter for aspirin-resistant (79.60-115 s) than for aspirin-sensitive (100.60-240 s) patients (p < 0.01). 11-dTXB(2) levels did not correlate with aspirin resistance. Aspirin-resistant patients had higher 11-dTXB(2) levels before (7297 vs. 4160 pg/mg creatinine; p < 0.01) and after (2153 vs. 1412 pg/mg; p = 0.03) aspirin, with a similar percentage decrease in thromboxane (70.5% vs. 66.1%; p = 0.43). Our findings suggest that resistance is not entirely due to lack of inhibition of platelet thromboxane production. Alternative sources of thromboxane and thromboxane-independent mechanisms, such as ADP-induced platelet activation, may contribute to aspirin resistance.

Comprehensive assessment of patent ductus arteriosus by echocardiography before transcatheter closure.

BACKGROUND: Anatomic type and angiographic measurements of patent ductus arteriosus (PDA) are used to determine the suitability of transcatheter closure (TCC). The purpose of this study is to evaluate whether these PDA features can be obtained by 2-dimensional echocardiography (2DE). METHODS: We retrospectively compared PDA measurements and type from 36 patients submitted to TCC between November 1995 and October 2000. RESULTS: The patient age ranged between 2 months to 10.5 years (median = 1.2 years). A significant correlation was found between measurements of PDA minimal diameter (R(2) = 0.88) and diameter at aortic ostium (R(2) = 0.72); whereas a poor correlation existed between measurements of the ampulla length. The 2DE and angiographic PDA classification were concordant in 31 of 36 (86%) patients. CONCLUSION: Our data support the use of 2DE measurements of PDA minimal diameter and PDA diameter at the aortic end to assess suitability for TCC. In the majority of cases, PDA type can be diagnosed by 2DE.

Utility of Exercise Testing to Assess Aortic Recoarctation.

Because it is not known how often and how uniformly exercise testing is used to "unmask" recurrent or persistent coarctation of the aorta, this study was designed to determine (a) the frequency with which exercise testing is used by the clinician to evaluate patients after coarctation repair, and (b) the hemodynamic measures obtained with exercise that are considered to be indicative of significant persistent or recurrent coarctation. Questionnaires were sent to 80 randomly selected pediatric cardiologists; 49 were returned completed. About half of the respondents performed exercise testing (ET) on all of their patients after coarctation repair and 75 % tested at least half. Those who supervised an exercise laboratory used ET for a significantly greater number of their patients. In descending order, rest arm-leg gradient (ALG), maximal exercise systolic blood pressure (MXBP), and postexercise ALG were considered the most important indicators of significant recoarctation. The majority of respondents made decisions based on data from the ET that were consistent with published guidelines.