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.

Usefulness of PREDIC3T Case Type Risk Category in the CRISP Registry

Procedural risk in Congenital Cardiac Catheterization (PREDIC3T) was recently reported as the contemporary procedure-type risk metric by the Congenital Cardiac Catheterization Project on Outcomes (C3PO) registry. The usefulness of this metric has not been evaluated elsewhere. The CRISP registry of Congenital Cardiovascular Interventional Study Consortium (CCISC) data set was analyzed. The study period was 14 years (2009 to 2022). The primary outcome was significant adverse event (SAE). Cases were assigned to the 6 PREDIC3T risk categories. Univariate and multivariable logistic regression models were used to evaluate the association between PREDIC3T and the primary outcome. The model discriminative performance was evaluated by the c-statistic. In a total of 64,419 enrolled cases, PREDIC3T case types were assigned in 59,822 cases (93%). The frequency for PREDIC3T category was 0 = 7,494 (12.5%), 1 = 16,932 (28.3%), 2 = 17,023 (28.5%), 3 = 9,885 (16.5%), 4 = 4,403 (7.4%), and 5 = 4,085 (6.8%). SAE was observed in 2,474 cases (4.1%). The SAE rates for category were 0 = 1.0%, 1 = 2.3%, 2 = 4.0%, 3 = 6.2%, 4 = 8.2%, and 5 = 9.0%. In a multivariable model, PREDIC3T case type risk category (odds ratios for category: 0 = 0.49, 1 = 1.00, 2 = 1.40, 3 = 2.06, 4 = 2.79, and 5 = 3.15; p <0.001) were significantly associated with SAE (c-statistic of 0.707) after adjusting for age, preprocedural inotropic support and systemic illness, low systemic saturation, high pulmonary vascular resistance, and the use of general anesthesia. The PREDIC3T case type risk category was associated with the risk of SAE in the CRISP registry data set and appeared to be a useful procedural risk classification tool.

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.

Improved catheter tracking during cardiovascular magnetic resonance-guided cardiac catheterization using overlay visualization

INTRODUCTION

Cardiovascular magnetic resonance (CMR)-guided cardiac catheterization is becoming more widespread due to the ability to acquire both functional CMR measurements and diagnostic catheterization data without exposing patients to ionizing radiation. However, the real-time imaging sequences used for catheter guidance during these procedures are limited in resolution and the anatomical detail they can provide. In this study, we propose a passive catheter tracking approach which simultaneously improves catheter tracking and visualization of the anatomy.

METHODS

60 patients with congenital heart disease underwent CMR-guided cardiac catheterization on a 1.5T CMR scanner (Ingenia, Philips Healthcare, Best the Netherlands) using the Philips iSuite system. The proposed T1-overlay technique uses a commercially available heavily T1-weighted sequence to image the catheter, and overlays it on a high-resolution 3D dataset within iSuite in real-time. Suppressed tissue in the real-time images enables the use of a thick imaging slab to assist in tracking of the catheter. Improvement in catheter visualization time was compared between T1-overlay and the conventional invasive CMR (iCMR) balanced steady state free precession (bSSFP) sequence. This technique also enabled selective angiography visualization for real-time evaluation of blood flow dynamics (such as pulmonary transit time), similar to direct contrast injection under standard fluoroscopy. Estimates of pulmonary transit time using iCMR were validated using x-ray fluoroscopy in 16 patients.

RESULTS

The T1-overlay approach significantly increased the time that the catheter tip was kept in view by the technologist compared to the bSSFP sequence conventionally used for iCMR. The resulting images received higher ratings for blood/balloon contrast, anatomy visualization, and overall suitability for iCMR guidance by three cardiologists. iCMR selective angiography using T1-overlay also provided accurate estimates of pulmonary transit time that agreed well with x-ray fluoroscopy.

CONCLUSION

We demonstrate a new passive catheter tracking technique using the iSuite platform that improves visualization of the catheter and cardiac anatomy. These improvements significantly increase the time that the catheter tip is seen throughout the procedure. We also demonstrate the feasibility of iCMR selective angiography for the measurement of pulmonary transit time.

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.

Fick versus flow: a real-time invasive cardiovascular magnetic resonance (iCMR) reproducibility study

BACKGROUND

Cardiac catheterization and cardiovascular magnetic resonance (CMR) imaging have distinct diagnostic roles in the congenital heart disease (CHD) population. Invasive CMR (iCMR) allows for a more thorough assessment of cardiac hemodynamics at the same time under the same conditions. It is assumed but not proven that iCMR gives an incremental value by providing more accurate flow quantification.

METHODS

Subjects with CHD underwent real-time 1.5 T iCMR using a passive catheter tracking technique with partial saturation pulse of 40° to visualize the gadolinium-filled balloon, CMR-conditional guidewire, and cardiac structures simultaneously to aid in completion of right (RHC) and left heart catheterization (LHC). Repeat iCMR and catheterization measurements were performed to compare reliability by the Pearson (PCC) and concordance correlation coefficients (CCC).

RESULTS

Thirty CHD (20 single ventricle and 10 bi-ventricular) subjects with a median age and weight of 8.3 years (2-33) and 27.7 kg (9.2-80), respectively,  successfully underwent iCMR RHC and LHC. No catheter related complications were encountered. Time taken for first pass RHC and LHC/aortic pull back was 5.1, and 2.9 min, respectively. Total success rate to obtain required data points to complete Fick principle calculations for all patients was 321/328 (98%). One patient with multiple shunts was an outlier and excluded from further analysis. The PCC for catheter-derived pulmonary blood flow (Qp) (0.89, p < 0.001) is slightly lower than iCMR-derived Qp (0.96, p < 0.001), whereas catheter-derived systemic blood flow (Qs) (0.62, p = < 0.001) was considerably lower than iCMR-derived Qs (0.94, p < 0.001). CCC agreement for Qp at baseline (C1-CCC = 0.65, 95% CI 0.41-0.81) and retested conditions (C2-CCC = 0.78, 95% CI 0.58-0.89) were better than for Qs at baseline (C1-CCC = 0.22, 95% CI - 0.15-0.53) and retested conditions (C2-CCC = 0.52, 95% CI 0.17-0.76).

CONCLUSION

This study further validates hemodynamic measurements obtained via iCMR. iCMR-derived flows have considerably higher test-retest reliability for Qs. iCMR evaluations allow for more reproducible hemodynamic assessments in the CHD population.

Bioresorbable Stent to Manage Congenital Heart Defects in Children

Intravascular stents for pediatric patients that degrade without inhibiting vessel growth remain a clinical challenge. Here, poly(L-lactide) fibers (DH-BDS) at two thicknesses, 250 μm and 300 μm, were assembled into large, pediatric-sized stents (Ø10 - Ø20 mm). Fibers were characterized mechanically and thermally, then stent mechanical properties were compared to metal controls, while mass loss and degradation kinetics modeling estimated total stent degradation time. Thicker fibers displayed lower stiffness (1969 ± 44 vs 2126 ± 37 MPa) and yield stress (117 ± 12 vs 137 ± 5 MPa) than thinner counterparts, but exhibited similar fail strength (478 ± 28 vs 476 ± 16 MPa) at higher strains (47 ± 2 vs 44 ± 2%). Stents all exhibited crystallinity between 51.3 - 54.4% and fiber glass transition temperatures of 88.6 ± 0.5 °C and 84.6 ± 0.5 °C were well above physiological ranges. Radial strength (0.31 ± 0.01 - 0.34 ± 0.02 N/mm) in thinner stents was similar to metal stents (0.24 - 0.41 N/mm) up to Ø14 mm with no foreshortening and thicker coils granted comparable radial strength (0.32 ± 0.02 - 0.34 ± 0.02 N/mm) in stents larger than Ø14 mm. Both 10 mm (1.17 ± 0.02 % and 0.86 ± 0.1 %) and 12 mm (1.1 ± 0.03% and 0.89 ± 0.1%) stents exhibited minimal weight loss over one year. Degradation kinetics models predicted full stent degradation within 2.8 - 4.5 years depending on thickness. DH-BDS exhibiting hoop strength similar to metal stents and demonstrating minimal degradation and strength loss over the first year before completely disappearing within 3 to 4.5 years show promise as a pediatric interventional alternative to current strategies.

MRI for Guided Right and Left Heart Cardiac Catheterization: A Prospective Study in Congenital Heart Disease

BACKGROUND

Improvements in outcomes for patients with congenital heart disease (CHD) have increased the need for diagnostic and interventional procedures. Cumulative radiation risk is a growing concern. MRI-guided interventions are a promising ionizing radiation-free, alternative approach.

PURPOSE

To assess the feasibility of MRI-guided catheterization in young patients with CHD using advanced visualization passive tracking techniques.

STUDY TYPE

Prospective.

POPULATION

A total of 30 patients with CHD referred for MRI-guided catheterization and pulmonary vascular resistance analysis (median age/weight: 4 years / 15 kg).

FIELD STRENGTH/SEQUENCE

1.5T; partially saturated (pSAT) real-time single-shot balanced steady-state free-precession (bSSFP) sequence.

ASSESSMENT

Images were visualized by a single viewer on the scanner console (interactive mode) or using a commercially available advanced visualization platform (iSuite, Philips). Image quality for anatomy and catheter visualization was evaluated by three cardiologists with >5 years' experience in MRI-catheterization using a 1-5 scale (1, poor, 5, excellent). Catheter balloon signal-to-noise ratio (SNR), blood and myocardium SNR, catheter balloon/blood contrast-to-noise ratio (CNR), balloon/myocardium CNR, and blood/myocardium CNR were measured. Procedure findings, feasibility, and adverse events were recorded. A fraction of time in which the catheter was visible was compared between iSuite and the interactive mode.

STATISTICAL TESTS

T-test for numerical variables. Wilcoxon signed rank test for categorical variables.

RESULTS

Nine patients had right heart catheterization, 11 had both left and right heart catheterization, and 10 had single ventricle circulation. Nine patients underwent solely MRI-guided catheterization. The mean score for anatomical visualization and contrast between balloon tip and soft tissue was 3.9 ± 0.9 and 4.5 ± 0.7, respectively. iSuite provided a significant improvement in the time during which the balloon was visible in relation to interactive imaging mode (66 ± 17% vs. 46 ± 14%, P < 0.05).

DATA CONCLUSION

MRI-guided catheterizations were carried out safely and is feasible in children and adults with CHD. The pSAT sequence offered robust and simultaneous high contrast visualization of the catheter and cardiac anatomy.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 1.

Lymphatic pathway evaluation in congenital heart disease using 3D whole-heart balanced steady state free precession and T2-weighted cardiovascular magnetic resonance

BACKGROUND

Due to passive blood flow in palliated single ventricle, central venous pressure increases chronically, ultimately impeding lymphatic drainage. Early visualization and treatment of these malformations is essential to reduce morbidity and mortality. Cardiovascular magnetic resonance (CMR) T2-weighted lymphangiography (T2w) is used for lymphatic assessment, but its low signal-to-noise ratio may result in incomplete visualization of thoracic duct pathway. 3D-balanced steady state free precession (3D-bSSFP) is commonly used to assess congenital cardiac disease anatomy. Here, we aimed to improve diagnostic imaging of thoracic duct pathway using 3D-bSSFP.

METHODS

Patients underwent CMR during single ventricle or central lymphatic system assessment using T2w and 3D-bSSFP. T2w parameters included 3D-turbo spin echo (TSE), TE/TR = 600/2500 ms, resolution = 1 × 1 × 1.8 mm, respiratory triggering with bellows. 3D-bSSFP parameters included electrocardiogram triggering and diaphragm navigator, 1.6 mm isotropic resolution, TE/TR = 1.8/3.6 ms. Thoracic duct was identified independently in T2w and 3D-bSSFP images, tracked completely from cisterna chyli to its drainage site, and classified based on severity of lymphatic abnormalities.

RESULTS

Forty-eight patients underwent CMR, 46 of whom were included in the study. Forty-five had congenital heart disease with single ventricle physiology. Median age at CMR was 4.3 year (range 0.9-35.1 year, IQR 2.4 year), and median weight was 14.4 kg (range, 7.9-112.9 kg, IQR 5.2 kg). Single ventricle with right dominant ventricle was noted in 31 patients. Thirty-eight patients (84%) were status post bidirectional Glenn and 7 (16%) were status post Fontan anastomosis. Thoracic duct visualization was achieved in 45 patients by T2w and 3D-bSSFP. Complete tracking to drainage site was attained in 11 patients (24%) by T2w vs 25 (54%) by 3D-bSSFP and in 28 (61%) by both. Classification of lymphatics was performed in 31 patients.

CONCLUSION

Thoracic duct pathway can be visualized by 3D-bSSFP combined with T2w lymphangiography. Cardiac triggering and respiratory navigation likely help retain lymphatic signal in the retrocardiac area by 3D-bSSFP. Visualizing lymphatic system leaks is challenging on 3D-bSSFP images alone, but 3D-bSSFP offers good visualization of duct anatomy and landmark structures to help plan interventions. Together, these sequences can define abnormal lymphatic pathway following single ventricle palliative surgery, thus guiding lymphatic interventional procedures.

Interventional Cardiovascular Magnetic Resonance Imaging (iCMR) in an Adolescent with Pulmonary Hypertension

The interventional cardiac magnetic resonance imaging (iCMR) catheterization procedure is feasible and safe for children and adults with pulmonary hypertension and congenital heart defects (CHD). With iCMR, the calculation of pulmonary vascular resistance (PVR) in children with complex CHD with multilevel shunt lesions is accurate. In this paper, we describe the role of the MRI-guided right-sided cardiac catheterization procedure to accurately estimate PVR in the setting of multiple shunt lesions (ventricular septal defect and patent ductus arteriosus) and to address the clinical question of operability in an adolescent with trisomy 21 and severe pulmonary hypertension.

Use of institutional criteria for transcatheter device closure of Fontan fenestration - Midterm outcomes

Background:

There are no established criteria to decide suitability for Fontan fenestration closure. Our institution has the following criteria: an unobstructed Fontan pathway with no significant decompressing venovenous collaterals, baseline Fontan pressure ≤15 mmHg, baseline cardiac index ≥2 L/min/m², and a decrease in cardiac index ≤20% with test occlusion of the fenestration.

Objective:

The objective of the study was to review midterm outcomes following device closure of Fontan fenestration using institutional criteria.

Materials and Methods:

A retrospective review was performed of patients who underwent catheterization with prior fenestrated Fontan procedure between May 2005 and January 2015. Patients were classified as those who underwent successful closure (A), had closure deferred due to failure to meet criteria (B), or were not referred for closure (C).

Results:

There were 42 patients in Group A, 10 in Group B, and 150 in Group C. The mean Fontan pressure increased from 13.1 ± 2.1 to 14.5 ± 2.1mmHg in Group A and 14.6 ± 1.5 to 15.7 ± 2.2 mmHg in Group B (P = not significant). With test occlusion, cardiac index fell by 18.12% ± 15.68% in Group A and 33.75% ± 14.98% in Group B (P = 0.019). At a median of 46 month follow-up, oxygen saturation increased significantly from 85.15% ± 6.29% at baseline to 94.6% ± 4.43% (P < 0.001) in Group A but with no statistically significant difference in the rates of plastic bronchitis, protein-losing enteropathy, stroke, or heart transplantation between the three groups.

Conclusions:

Using institutional criteria, transcatheter device closure of Fontan fenestration was followed by significant increase in oxygen saturations and no statistically significant difference in morbidity or mortality between closure and nonclosure groups.

Invasive cardiovascular magnetic resonance (iCMR) for diagnostic right and left heart catheterization using an MR-conditional guidewire and passive visualization in congenital heart disease

BACKGROUND

Today's standard of care, in the congenital heart disease (CHD) population, involves performing cardiac catheterization under x-ray fluoroscopy and cardiac magnetic resonance (CMR) imaging separately. The unique ability of CMR to provide real-time functional imaging in multiple views without ionizing radiation exposure has the potential to be a powerful tool for diagnostic and interventional procedures. Limiting fluoroscopic radiation exposure remains a challenge for pediatric interventional cardiologists. This pilot study's objective is to establish feasibility of right (RHC) and left heart catheterization (LHC) during invasive CMR (iCMR) procedures at our institution in the CHD population. Furthermore, we aim to improve simultaneous visualization of the catheter balloon tip, MR-conditional guidewire, and cardiac/vessel anatomy during iCMR procedures.

METHODS

Subjects with CHD were enrolled in a pilot study for iCMR procedures at 1.5 T with an MR-conditional guidewire. The CMR area is located adjacent to a standard catheterization laboratory. Using the interactive scanning mode for real-time control of the imaging location, a dilute gadolinium-filled balloon-tip catheter was used in combination with an MR-conditional guidewire to obtain cardiac saturations and hemodynamics. A recently developed catheter tracking technique using a real-time single-shot balanced steady-state free precession (bSSFP), flip angle (FA) 35-45°, echo time (TE) 1.3 ms, repetition time (TR) 2.7 ms, 40° partial saturation (pSAT) pre-pulse was used to visualize the gadolinium-filled balloon, MR-conditional guidewire, and cardiac structures simultaneously. MR-conditional guidewire visualization was enabled due to susceptibility artifact created by distal markers. Pre-clinical phantom testing was performed to determine the optimum imaging FA-pSAT combination.

RESULTS

The iCMR procedure was successfully performed to completion in 31/34 (91%) subjects between August 1st, 2017 to December 13th, 2018. Median age and weight were 7.7 years and 25.2 kg (range: 3 months - 33 years and 8 - 80 kg). Twenty-one subjects had single ventricle (SV) anatomy: one subject was referred for pre-Glenn evaluation, 11 were pre-Fontan evaluations and 9 post-Fontan evaluations for protein losing enteropathy (PLE) and/or cyanosis. Thirteen subjects had bi-ventricular (BiV) anatomy, 4 were referred for coarctation of the aorta (CoA) evaluations, 3 underwent vaso-reactivity testing with inhaled nitric oxide, 3 investigated RV volume dimensions, two underwent branch PA stenosis evaluation, and the remaining subject was status post heart transplant. No catheter related complications were encountered. Average time taken for first pass RHC, LHC/aortic pull back, and to cross the Fontan fenestration was 5.2, 3.0, and 6.5 min, respectively. Total success rate to obtain required data points to complete Fick principle calculations for all patients was 331/337 (98%). Subjects were transferred to the x-ray fluoroscopy lab if further intervention was required including Fontan fenestration device closure, balloon angioplasty of pulmonary arteries/conduits, CoA stenting, and/or coiling of aortopulmonary (AP) collaterals. Starting with subject #10, an MR-conditional guidewire was used in all subsequent subjects (15 SV and 10 BiV) with a success rate of 96% (24/25). Real-time CMR-guided RHC (25/25 subjects, 100%), retrograde and prograde LHC/aortic pull back (24/25 subjects, 96%), CoA crossing (3/4 subjects, 75%) and Fontan fenestration test occlusion (2/3 subjects, 67%) were successfully performed in the majority of subjects when an MR-conditional guidewire was utilized.

CONCLUSION

Feasibility for detailed diagnostic RHC, LHC, and Fontan fenestration test occlusion iCMR procedures in SV and BiV pediatric subjects with complex CHD is demonstrated with the aid of an MR-conditional guidewire. A novel real-time pSAT GRE sequence with optimized FA-pSAT angle has facilitated simultaneous visualization of the catheter balloon tip, MR-conditional guidewire, and cardiac/vessel anatomy during iCMR procedures.

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.

Biodegradable Stents for Congenital Heart Disease

The quest for an ideal biodegradable stent for both adult coronary and pediatric congenital heart disease applications continues. Over the past few years, a lot of progress has been made toward development of a dedicated pediatric biodegradable stent that can be used for congenital heart disease applications. At present, there are no biodegradable stents available for use in congenital heart disease. In this article, the authors review the different biodegradable materials and their limitations and provide an overview of the current biodegradable stents being evaluated for congenital heart disease applications.

Hypoplastic left heart syndrome secondary to intrauterine rhabdomyoma necessitating single ventricle palliation

Rhabdomyoma, a benign hamartomatous tumor of the cardiac embryonic myocyte, is the most common intrauterine cardiac tumor and accounts for 0.12% of prenatal fetal studies. Fetal cardiac rhabdomyomas increase in size during second and early third trimester and spontaneously regress postnatally. The clinical presentation is usually benign, however, compromise of the ventricular outflow tract leading to decreased cardiac output and fetal death have been reported. We present a case of large cardiac rhabdomyoma in a fetus that might have caused complete left ventricular outflow tract obstruction and development of hypoplastic left heart syndrome (HLHS) necessitating postnatal single ventricle palliation therapy. The clinical course and outcomes of prenatally diagnosed cardiac rhabdomyoma are reviewed and theories of the development of hypoplastic left heart syndrome are explored.

A novel design biodegradable stent for use in congenital heart disease: mid-term results in rabbit descending aorta

OBJECTIVES

This study evaluates the feasibility of delivery and deployment of low and medium molecular weight (LMW and MMW, respectively) double-opposing helical (DH) poly-l-lactic acid biodegradable stent (BDS) in rabbit descending aorta (DAO). Secondary objectives were to assess patency and inflammation of stented vessels at 9 months and to investigate safety following intentional embolization of stent fragments in DAO.

BACKGROUND

A BDS that will relieve aortic obstruction and disappears as the child grows older allowing for preservation of aortic wall elasticity and natural growth of aorta will be ideal to treat Coarctation (CoA). BDS have never been evaluated in the DAO.

METHODS

Seven New Zealand white rabbits underwent implantation of DH-LMW (n = 7), DH-MMW (n = 3), and metal stents (n = 7) in DAO. BDS fragments were intentionally embolized into DAO in two rabbits.

RESULTS

All stents were deployed via a 6-French sheath. Five BDS covered the origin of major DAO side branches. Angiography and intravascular ultrasound showed good stent apposition to the wall of DAO with minimal luminal loss at 9 months follow-up. All stents had minimal neointimal hyperplasia on histopathology. Adverse events included 1 death, 1 aortic aneurysm, and lower extremity ulceration due to self-mutilation in an embolization rabbit.

CONCLUSIONS

Pilot study confirms the feasibility of delivery and deployment of up to 6-millimeter diameter DH BDS in rabbit DAO. Stent integrity with DH design was maintained at 9 months with minimal vessel inflammation. Potential morbidity due to embolized BD fragments cannot be ruled out and needs further evaluation.

Amplatzer vascular plug IV for occlusion of pulmonary arteriovenous malformations in a patient with cryptogenic stroke

Paradoxical embolism resulting in cryptogenic stroke has received much attention recently, with the primary focus on patent foramen ovale (PFO). However, it is essential to be vigilant in the search for other causes of paradoxical embolic events, such as pulmonary arteriovenous malformations (PAVM). We describe successful closure of pulmonary AVM with a St Jude Medical (Plymouth, MN) Amplatzer™ vascular plug IV. The newer AVP-IV devices can be used for successful embolization of tortuous pulmonary AVM in remote locations where use of other traditional devices may be technically challenging.