Selective Use of Pulmonary Vasodilators in Patients with Fontan Physiology.

Background: Fontan-associated liver disease is a well-known sequela following the Fontan procedure for patients living with single-ventricle heart disease. Pulmonary vasodilators, such as phosphodiesterase type 5 inhibitors, have emerged as a potential therapeutic option for lowering central venous pressures by reducing pulmonary vascular resistance. Method: We performed a single-center retrospective review of Fontan patients who were placed on pulmonary vasodilator therapy with prehemodynamic and posthemodynamic, MR elastography, and histologic assessments. Results: A total of 125 patients with Fontan circulation underwent surveillance with cardiac catheterization during the review period. Fifty-three (42%) patients who did not have increased end-diastolic pressures at the time of cardiac catheterization were started on phosphodiesterase type 5 inhibitor therapy. Nine patients (17%) underwent posttherapy follow-up catheterization. The mean Fontan pressure decreased from 15.4 ± 3.3 mmHg to 13.3 ± 2.5 mmHg (p=0.026), after initiation of pulmonary vasodilatory therapy. There was no change in end-diastolic pressure, transpulmonary gradient, wedge pressure, pulmonary vascular resistance, cardiac index, or saturation. Eleven patients (21%) underwent pretherapy MR elastography testing with posttherapy follow-up MR elastography. We found no improvement in liver stiffness score following the application of pulmonary vasodilators. Three patients underwent pretherapy and posttherapy liver biopsies, with variable histological changes observed within the hepatic parenchyma. Conclusions: These data demonstrate indeterminate results for the selective use of pulmonary vasodilators but highlight the need for large prospective randomized control trials of pulmonary vasodilator therapies to fully assess the benefit of such therapies in Fontan-associated liver disease.

Institutional Trend in Device Selection for Transcatheter PDA Closure in Premature Infants.

We report our experience with transcatheter patent ductus arteriosus (PDA) closure in premature infants and compare patients grouped by the device used for closure: the Microvascular Plug, "MVP" (Medtronic, Minneapolis, MN); Micro Plug Set, "Micro Plug" (KA Medical, Minneapolis, MN); and Amplatzer Piccolo Occluder, "Piccolo" (Abbot, Santa Clara, CA). We also report trends in device selection over time. Studies examining outcomes according to device selection for PDA closure in premature infants are lacking. We performed a retrospective review of all percutaneous PDA closures in premature infants at a single center (June 2018-May 2021). Patients were grouped by initial device selected for PDA closure (intention to treat). Institutional Review Board approval was obtained. 58 premature infants [MVP (n = 25), Micro Plug (n = 25), and Piccolo (n = 8)] underwent successful transcatheter PDA closure (mean gestational age 27 weeks 2 days; mean weight at procedure 1.4 kg; mean age at procedure 28 days). Pre-procedural demographics, procedural data, and follow-up data were similar between groups. There were no significant procedural adverse events. Three devices (2 MVP, 0 Micro Plug, 1 Piccolo p = 0.27) embolized after the procedure. One other device was removed for concern for aortic obstruction. Device selection evolved with a clear trend toward the Micro Plug device over time. Demographic, procedural, and follow-up data were similar between the MVP, Micro Plug, and Piccolo groups. The Micro Plug did not require exchange for suboptimal fitting or embolize and became our preferred device in most cases.

Selective Valve Removal for Melody Valve Endocarditis: Practice Variations in a Multicenter Experience.

Guidelines for management of Melody transcatheter pulmonary valve (TPV) infective endocarditis (IE) are lacking. We aimed to identify factors associated with surgical valve removal versus antimicrobial therapy in Melody TPV IE. Multicenter retrospective analysis of all patients receiving Melody TPV from 10/2010 to 3/2019 was performed to identify cases of IE. Surgical explants versus non-surgical cases were compared. Of the 663 Melody TPV implants, there were 66 cases of IE in 59 patients (59/663, 8.8%). 39/66 (59%) were treated with IV antimicrobials and 27/66(41%) underwent valve explantation. 26/59 patients (44%) were treated medically without explantation or recurrence with average follow-up time of 3.5 years (range:1-9). 32% of Streptococcus cases, 53% of MSSA, and all MRSA cases were explanted. 2 of the 4 deaths had MSSA. CART analysis demonstrated two important parameters associated with explantation: a peak echo gradient ≥ 47 mmHg at IE diagnosis(OR 10.6, p < 0.001) and a peak echo gradient increase of > 24 mmHg compared to baseline (OR 6.7, p = 0.01). Rates of explantation varied by institution (27 to 64%). In our multicenter experience, 44% of patients with Melody IE were successfully medically treated without valve explantation or recurrence. The degree of valve stenosis at time of IE diagnosis was strongly associated with explantation. Rates of explantation varied significantly among the institutions.

Abnormal pulmonary perfusion heterogeneity in patients with Fontan circulation and pulmonary arterial hypertension.

KEY POINTS: The distribution of pulmonary perfusion is affected by gravity, vascular branching structure and active regulatory mechanisms, which may be disrupted by cardiopulmonary disease, but this is not well studied, particularly in rare conditions. We evaluated pulmonary perfusion in patients who had undergone Fontan procedure, patients with pulmonary arterial hypertension (PAH) and two groups of controls using a proton magnetic resonance imaging technique, arterial spin labelling to measure perfusion. Heterogeneity was assessed by the relative dispersion (SD/mean) and gravitational gradients. Gravitational gradients were similar between all groups, but heterogeneity was significantly increased in both patient groups compared to controls and persisted after removing contributions from large blood vessels and gravitational gradients. Patients with Fontan physiology and patients with PAH have increased pulmonary perfusion heterogeneity that is not explainable by differences in mean perfusion, gravitational gradients, or large vessel anatomy. This probably reflects vascular remodelling in PAH and possibly in Fontan physiology. ABSTRACT: Many factors affect the distribution of pulmonary perfusion, which may be disrupted by cardiopulmonary disease, but this is not well studied, particularly in rare conditions. An example is following the Fontan procedure, where pulmonary perfusion is passive, and heterogeneity may be increased because of the underlying pathophysiology leading to Fontan palliation, remodelling, or increased gravitational gradients from low flow. Another is pulmonary arterial hypertension (PAH), where gravitational gradients may be reduced secondary to high pressures, but remodelling may increase perfusion heterogeneity. We evaluated regional pulmonary perfusion in Fontan patients (n = 5), healthy young controls (Fontan control, n = 5), patients with PAH (n = 6) and healthy older controls (PAH control) using proton magnetic resonance imaging. Regional perfusion was measured using arterial spin labelling. Heterogeneity was assessed by the relative dispersion (SD/mean) and gravitational gradients. Mean perfusion was similar (Fontan = 2.50 ± 1.02 ml min-1  ml-1 ; Fontan control = 3.09 ± 0.58, PAH = 3.63 ± 1.95; PAH control = 3.98 ± 0.91, P = 0.26), and the slopes of gravitational gradients were not different (Fontan = -0.23 ± 0.09 ml min-1  ml-1  cm-1 ; Fontan control = -0.29 ± 0.23, PAH = -0.27 ± 0.09, PAH control = -0.25 ± 0.18, P = 0.91) between groups. Perfusion relative dispersion was greater in both Fontan and PAH than controls (Fontan = 1.46 ± 0.18; Fontan control = 0.99 ± 0.21, P = 0.005; PAH = 1.22 ± 0.27, PAH control = 0.91 ± 0.12, P = 0.02) but similar between patient groups (P = 0.13). These findings persisted after removing contributions from large blood vessels and gravitational gradients (all P < 0.05). We conclude that patients with Fontan physiology and PAH have increased pulmonary perfusion heterogeneity that is not explained by differences in mean perfusion, gravitational gradients, or large vessel anatomy. This probably reflects the effects of remodelling in PAH and possibly in Fontan physiology.

Infants with pulmonary atresia intact ventricular septum who require balloon atrial septostomy have significantly higher 18-month mortality.

INTRODUCTION: Many newborns with pulmonary atresia/intact ventricular septum require intervention to establish pulmonary flow and sufficient cardiac output. The resulting haemodynamic changes are not well characterised and may have unintended consequences. METHODS: This is a 30-year (1988-2018) retrospective study of patients with pulmonary atresia intact ventricular septum. RESULTS: Eighty-nine patients were included, and median follow-up was 8 years. Fifty-five per cent had coronary sinusoids and 27% had right ventricular-dependent coronary circulation. Most patients were managed with surgical aortopulmonary or modified Blalock-Taussig shunt (73%), and 12 patients underwent balloon atrial septostomy before surgical intervention. The remaining patients (27%) underwent only transcatheter interventions; 7 required an atrial septostomy and 17 required ductal stentings. All-cause mortality was 10%, most deaths (89%) occurred before 18 months of age. Of these early deaths, 87% required a balloon atrial septostomy and 85% had right ventricular-dependent coronary sinusoids. Eighteen-month mortality was significantly higher for patients who required a balloon atrial septostomy compared to those who did not (36% versus 1.4% p < 0.0001). DISCUSSION: Patients with pulmonary atresia/intact ventricular septum who require balloon atrial septostomy in the newborn period have significantly higher 18-month mortality. Quantifying the mortality difference may help guide prognostication and expectation setting. Infants who had septostomy and a surgical shunt in the newborn period fared better than those who only underwent septostomy (even when accompanied by ductal stenting). For infants with right ventricular-dependent circulation, atrial septostomy should only be performed on an urgent or emergent basis and these patients should be considered for early surgical intervention and neonatal transplant.

Early experience with the Micro Plug Set for preterm patent ductus arteriosus closure.

OBJECTIVES: We intend to describe early experience using a new, commercially available Micro Plug Set for preterm neonate and infant transcatheter patent ductus arteriosus (PDA) occlusion. BACKGROUND: Transcatheter PDA occlusion in premature neonates and small infants is safe and effective. The procedure is early in its evolution. METHODS: Procedural and short-term outcomes of preterm neonates and infants undergoing transcatheter PDA occlusion with a new, commercially available device were reviewed. RESULTS: Eight preterm neonates and infants born at median 27 weeks gestation (23-36 weeks) underwent transcatheter PDA device closure with the Micro Plug Set. The device is short (2.5 mm) with a range of diameters (3, 4, 5, 6 mm) and delivered through a microcatheter. Procedures were performed at median 41 days of age (12-88 days) and at 1690 g (760-3,310 g). Transvenous PDA device occlusion was performed with fluoroscopic and echocardiography guidance. All procedures were successful with complete PDA occlusion. There were no procedural or short-term adverse events. CONCLUSIONS: Preterm neonate and infant transcatheter PDA device closure with a new, commercially available short and microcatheter delivered device (Micro Plug Set) was safe and effective in a small, early series of patients.

Radiation Risk Categories in Cardiac Catheterization for Congenital Heart Disease: A Tool to Aid in the Evaluation of Radiation Outcomes.

To stratify diverse procedure types into categories with similar radiation exposure in cardiac catheterization for congenital heart disease. Radiation exposures for a comprehensive list of specific procedure types and stratification of outcomes based on radiation risk are not currently available. Data between January 2014 and December 2015 were collected on all cases performed at sites participating in C3PO-QI (Congenital Cardiac Catheterization Outcomes Project-Quality Improvement Initiative) and 9 centers were included. Using expert consensus, 40 unique procedure types were defined by diagnostic characteristics or the intervention(s) performed, and dose area product (DAP) per kilogram of body weight (µGy × m2/kg) was summarized. Using empiric and consensus methods, three radiation risk categories were created. A total of 11,735 cases were included for analysis. Thirteen (n = 7918) procedure types with median DAP/kg < 100 were categorized in the low radiation exposure category (median DAP/kg 39). The medium exposure category (n = 1807) consisted of 16 procedure types with median DAP/kg values ranging 100 to < 200 (overall median DAP/kg 131). Finally, the high radiation exposure category (n = 1073) consisted of 11 procedure types with median DAP/kg ≥ 200 (overall median DAP/kg of 231). The radiation exposure risk categories created in this multi-center dataset are a critical step towards the development of a robust risk adjustment methodology for radiation exposure in catheterization for congenital heart disease.

Percutaneous obliteration of left ventricular cavity to eliminate aortic regurgitation and presumed coronary steal in an infant with hypoplastic left heart syndrome.

The phenomenon of coronary steal is well known in the setting of HLHS (Hypoplastic Left Heart Syndrome) early after the Classical Norwood Operation. We report a rare case of an infant with HLHS [Severe Aortic Stenosis (AS), Mitral Stenosis (MS) and small Left Ventricle (LV)], who developed aortic regurgitation and presumed coronary steal late after the Sano Modification of the Norwood Procedure. Coronary steal developed secondary to progressive aortic and mitral regurgitation and resulted in poor right ventricular function and severe tricuspid regurgitation. We describe a novel interventional approach for obliteration of the LV cavity by using hydrogel coils. LV obliteration eliminated the presumed steal and resulted in improvement in ventricular function, tricuspid regurgitation and clinical course.

Transcatheter stenting of the systemic-to-pulmonary artery shunt: A 7-year experience from a single tertiary center.

BACKGROUND: Systemic-to-pulmonary artery shunt (SPS) dysfunction can be deleterious in shunt dependent patients and traditionally have undergone surgical revision. Data on transcatheter stenting of SPS is limited. We sought to evaluate feasibility, safety and outcomes of stenting SPS. METHODS: Retrospective review of all patients who underwent transcatheter SPS stenting from 1/2006 to 12/2013. RESULTS: Of 229 surgically implanted SPS, 25 transcatheter stent interventions were performed in 22 patients. The majority had pulmonary atresia (n = 9) or HLHS (n = 10). Their median age was 4 ms (range 10 days to 4 years) and median weight 4.9 kg (range 3-14). Nine had a central and 15 had a BT shunt with a median shunt size of 3.75 mm (range 3-6). The interval from shunt placement to intervention was 1.9 ms (range 4 days-3.8 years). The indication for intervention was increasing cyanosis in10 patients and delaying final repair in 9. Two patients were on ECMO at the time of intervention. The median shunt diameter increased from 2.3 to 4.1 mm and oxygen saturation from 72 to 85% (P < 0.001). No intra-procedural complications were encountered. One patient died from aspiration (autopsy demonstrated a patent shunt), 13 progressed to repair or next stage, 6 remain palliated with shunts as they are deemed unfit for the next stage and 2 are awaiting surgery. CONCLUSIONS: Stenting of systemic to pulmonary artery shunt is a safe and effective procedure and avoids surgical re-intervention. It can be performed both as a rescue procedure in patients with acute shunt occlusion and as an elective procedure to palliate patients not yet suitable for subsequent corrective or staged repair.

Iatrogenic aortopulmonary communications after transcatheter interventions on the right ventricular outflow tract or pulmonary artery: Pathophysiologic, diagnostic, and management considerations.

OBJECTIVES: To investigate the spectrum, etiology, and management of traumatic aortopulmonary (AP) communications after transcatheter interventions on the pulmonary circulation. BACKGROUND: An iatrogenic AP communication is an unusual complication after balloon pulmonary artery (PA) angioplasty or stenting, or transcatheter pulmonary valve replacement (TPVR). However, with the increasing application of transcatheter therapies for postoperative PA stenosis and right ventricular outflow tract (RVOT) dysfunction, including percutaneous pulmonary valve replacement, consideration of the etiology, diagnosis, and management of this problem is important for interventional cardiologists performing such procedures. METHODS AND RESULTS: We present three new cases, as well as gross anatomy and histopathology data, related to AP communications after PA interventions. We also review the literature relevant to this topic. Including these new cases, there have been 18 reported cases of iatrogenic AP communication after transcatheter interventions on the PAs or RVOT, primarily patients with transposition of the great arteries who underwent PA angioplasty after an arterial switch operation, or after TPVR in patients who had undergone a Ross procedure. The likely cause of such defects is PA trauma plus distortion of the neo-aortic anastomosis resulting from angioplasty or stenting of the RVOT or central PAs, with subsequent dissection through the extravascular connective tissue and into the closely adjacent vessel through the devitalized tissue at the anastomosis. CONCLUSIONS: Cardiologists performing PA or RVOT interventions should be aware of the possibility of a traumatic AP communication and consider this diagnosis when confronted with suggestive signs and symptoms.

Low dose tissue plasminogen activator treatment for vascular thrombosis following cardiac catheterization in children: a single center experience.

OBJECTIVES: To assess the efficacy and safety of low dose tissue plasminogen activator (tPA) therapy in children with vascular thrombosis following cardiac catheterization. BACKGROUND: Currently, heparin is the standard of care for vascular thrombosis, however, it may not be efficacious in dissolving existing thrombi. Although tPA is an accepted thrombolytic therapy for life-threatening thrombosis in children, it is not a well-established treatment for the thrombosis of femoral vessels following cardiac catheterization. METHODS: A retrospective analysis was performed from 1/1/2009 until 6/30/2011 at Rady Children's Hospital-San Diego (RCHSD) reviewing all cases with venous or arterial thrombosis at the vascular access site following cardiac catheterization, and a survey was conducted among the Congenital Cardiovascular Interventional Study Consortium members regarding their experience in tPA therapy. RESULTS: At RCHSD, out of 1,155 catheterizations, 12 children developed femoral thrombosis. In three children, where 12-h heparin therapy was unsuccessful in resolving thrombosis, we used low-dose tPA according to the following regime: 0.05 mg/kg/h for 30 min, followed by 0.1 mg/kg/h for 4 h. We achieved thrombolysis in all cases evidenced by repeat ultrasound and return of palpable pulse with normal limb circulation. No complications were encountered. The survey confirmed that adult tPA dose (0.1-0.5 mg/kg/h) has 100% efficacy in resolving thrombi in children with vascular thrombosis, however, the rate of serious complications was not negligible (15%). CONCLUSION: tPA is an efficacious therapy to dissolve thrombi that developed as a complication of cardiac catheterization in children. The rate of complications due to tPA may be reduced using a lower dose: 0.05-0.1 mg/kg/h.

Transcatheter Hepatic Conduit-Azygous Vein Connection Reduces Pulmonary Arteriovenous Malformations in a Cyanotic Fontan Patient.

The authors report a closed-chest, transcatheter large-vessel connection (hepatic conduit to azygous vein) to reverse pulmonary arteriovenous malformations in a 10-year-old patient after Fontan for heterotaxy/interrupted inferior vena cava, with an increase in oxygen saturation from 78% to 96%. Computational fluid dynamics estimated a 14-fold increase in hepatic blood flow to the left pulmonary artery (from 1.3% to 14%). (Level of Difficulty: Advanced.).

Percutaneous stent implantation into coronary arteries in infants.

OBJECTIVES: To investigate the feasibility, procedural techniques, safety, and overall potential of percutaneous coronary angioplasty and stent implantation in infants with coronary artery disease and acute coronary syndrome. BACKGROUND: Despite extensive experience in adult patients, percutaneous coronary intervention remains uncommon in children and extremely rare in infants. METHODS: Retrospective review including all children who underwent percutaneous coronary angioplasty in Rady Children's Hospital-San Diego during a period of 4 years. RESULTS: Seven children including four children less than 15 months of age underwent percutaneous coronary intervention with coronary stent implantation in the proximal portion of the left or right coronary arteries. Successful stent placement with excellent revascularization was achieved in all cases. Mean coronary artery diameter was 0.65 mm prior to stent placement. Balloon angioplasty resulted in suboptimal resolution of coronary stenosis, thus bare metal stents were implanted in all cases, dilated to a mean of 2.5-mm internal diameter. Average intervention-free period was 434 days after stent implantation. In-stent re-stenosis and stent thrombosis did not occur if the implanted stent diameter was greater than 2.5 mm and the patient received dual anti-platelet therapy. CONCLUSIONS: Our experience suggests that coronary artery stent implantation is a feasible and relatively safe palliative option in infants and toddlers with coronary stenosis. It is a viable strategy for bridging patients with acute ischemia or poor ventricular function to elective surgical revascularization or transplantation.

Closure of perimembranous ventricular septal defects with aneurysmal tissue using the Amplazter Duct Occluder I: lessons learned and medium term follow up.

OBJECTIVES: The aim of this report is to describe our experience with closure of perimembranous ventricular septal defects (PMVSD) with aneurysm using the Amplatzer Duct Occluder I (ADO I). BACKGROUND: Atrio-ventricular block (AVB) remains the most troublesome complication of device closure of PMVSDs. Many PMVSDs are associated with an aneurysm that protrudes into the right ventricle. We believe that devices implanted entirely within the VSD aneurysm avoid the risk of AVB. METHODS: A retrospective analysis of patients with PMVSD and aneurysm who underwent attempted ADO I device closure between 3/2004 and 8/2010 [Rady Children's Hospital-San Diego (n = 16), Mattel Children's Hospital at UCLA (n = 4), and Straub Hospital in Honolulu (n = 1)]. RESULTS: Twenty-one patients (16 male) with PMVSD and aneurysm underwent cardiac catheterization for the purpose of VSD closure using an ADO I. Nineteen patients had successful ADO I implantation with the following devices: 10/8 (n = 8), 8/6 (n = 7), 6/4 (n = 3) and 12/10 (n = 2). The procedure was aborted in 2 cases due to temporary AVB and ventricular ectopy during catheterization. One patient developed hemolysis due device malposition and had surgical device retrieval and VSD closure. One patient had new trivial tricuspid regurgitation and in 5/19 the tricuspid regurgitation improved post device closure. Transient accelerated junctional rhythm occurred within 24 hr in 4 patients and nonsustained slow ventricular tachycardia occurred in one patient. At latest follow-up (up to 6 years, median 1.9 years) 11/18 had no residual shunt, 4/18 had trivial and 3/18 small residual shunt. No AVB has been observed. CONCLUSIONS: Percutaneous closure of PMVSD with aneurysm using the ADO I appears to have acceptable efficacy and risk. Atrio-ventricular block in up to mid-term follow up was not encountered.

Pulmonary Atresia With Intact Ventricular Septum: From Radiofrequency Perforation to Transcatheter Pulmonary Valve.

OBJECTIVES: We intend to describe an entirely transcatheter management pathway for patients with pulmonary atresia with intact ventricular septum (PA/IVS). BACKGROUND: PA/IVS is a rare cyanotic congenital heart lesion traditionally palliated with multiple procedures and surgeries. Entirely non-surgical transcatheter management from infancy to adulthood may be possible; however, the pathway from neonatal radiofrequency (RF) pulmonary valve perforation to later transcatheter pulmonary valve replacement (TPV) is not well described. METHODS: This retrospective study was performed at a pediatric cardiac center between 2007-2018. All patients with PA/IVS who were managed exclusively with catheterization-based interventions as neonates (RF perforation, pulmonary valvuloplasty, or ductal stenting) were analyzed. Demographic, procedural and clinical data were collected. RESULTS: Fifteen patients had exclusively catheterization-based RV decompression as neonates, 7 of whom did not require subsequent surgery. Six patients required a right ventricular outflow tract (RVOT) augmentation later in life; all were born before 2013. All 6 later had a TPV placed. Two of the patients underwent a surgical Glenn shunt alone. Of the 7 patients that never had surgery, 3 have since undergone a TPV, and 4 are awaiting candidacy for TPV placement. No patients with PA/IVS have had an RVOT augmentation at our institution since 2012. CONCLUSIONS: Patients with PA/IVS who undergo catheterization-based neonatal interventions can make it to TPV without requiring surgery. At our institution, there has been a shift in management over the last 8 years favoring entirely non-surgical transcatheter management from infancy to adulthood.

Purpose-Built Transcatheter Cavopulmonary Anastomosis Device Requirements: Multi-Modality Imaging Evaluation.

BACKGROUND/PURPOSE: Patients with a functional single ventricle undergo multiple, palliative open-heart surgeries. This includes a superior cavopulmonary anastomosis or bidirectional Glenn shunt. A less-invasive transcatheter approach may reduce morbidity. METHODS/MATERIALS: We analyzed pre-Glenn X-ray contrast angiography (XA), cardiac computed tomography (CT), and cardiac magnetic resonance (CMR) studies. RESULTS: Over an eleven-year period (1/2007 - 6/2017), 139 Glenn surgeries were performed at our institution. The typical age range at surgery was 59 - 371 days (median = 163; IQR = 138 - 203). Eight-nine XA, ten CT, and ten CMR studies obtained from these patients were analyzed. Cephalad SVC measurements (millimeters) were 7.3 ± 1.7 (XA), 7.7 ± 1.6 (CT) and 6.9 ± 1.8 (CMR). RPA measurements were 7.3 ± 1.9 (XA), 7.4 ± 1.6 (CT) and 6.6 ± 1.9 (CMR). Potential device lengths were 10.9 ± 6 - 17.4 ± 6.4 (XA), 10.1 ± 2.1 - 17.7 ± 2.4 (CT) and 17.3 ± 4. - 23.7 ± 5.5 (CMR). SVC-RPA angle (degrees) was 132.9 ± 13.2 (CT) and 140 ± 10.2 (MRI). Image quality of all CT (100%), almost all XA (SVC 100%, RPA 99%), and most MRI (SVC 80%, RPA 90%) were deemed sufficient. Parametric modeling virtual fit device with 10 mm diameter and 20 - 25 mm length was ideal. CONCLUSIONS: Ideal transcatheter cavopulmonary shunt device for the typical patient would be 10 mm in diameter and 20-25 mm in length.

Intravascular Ultrasound (IVUS) Provides the Filling for the Angiogram's Crust: Benefits of IVUS in Pediatric Interventional Cardiology.

BACKGROUND: Intravascular ultrasound (IVUS) is a catheter-based imaging modality that generates cross-sectional views of vessel walls and lumens. This technique is used in adult interventional and vascular surgeries to guide the management of coronary artery and peripheral arterial disease. IVUS has been described as superior to angiography in providing data about lesions of interest, including degree of vessel stenosis and stent apposition following intervention. IVUS use to guide transcatheter management of congenital heart disease is limited. OBJECTIVE: We reviewed our experience using IVUS as an adjunctive tool to diagnose lesions and assess intervention in pediatric patients during cardiac catheterization. METHODS AND RESULTS: A retrospective chart review of all pediatric patients who underwent IVUS during cardiac catheterization to evaluate the cross-sectional lumen of non-coronary vessel(s) at Rady Children's Hospital from January 2018 to December 2019 was performed. Median patient age was 637 days (range, 44-4328 days), with mean weight of 12.1 ± 9 kg. Twenty-six vessels were interrogated with IVUS (pulmonary venous stenosis [n = 8], coarctation [n = 5], branch pulmonary artery stenosis [n = 6], systemic shunts and conduits [n = 3], and other peripheral vasculature [n = 4]). IVUS added value in all cases (100%). We found that IVUS guided the intervention in 88% of procedures and defined the endpoint in 62% of transcatheter interventions. There were no IVUS-related complications. CONCLUSIONS: IVUS enhanced our diagnostic interpretation and identified occult lesions not visualized by angiography. IVUS was valuable in guiding and defining the endpoints of these interventions.

Bronchial stenting in infants with severe bronchomalacia: Technique and outcomes.

OBJECTIVES: To report the first use of a balloon expandable bare metal stent for treating infant bronchomalacia. BACKGROUND: Infant bronchomalacia often requires prolonged mechanical ventilation and can be life-threatening. Effective treatment for severe infant bronchomalacia continues to be elusive. We present three cases of bronchial stenting for no-option or treatment refractory infant bronchomalacia. METHODS: Three consecutive cases of stenting to relieve conservative treatment refractory severe infant bronchomalacia were performed between February 2019 and December 2020. Initial diagnosis was confirmed with Computed Tomography (CT) angiography. Patients underwent rigid micro laryngoscopy, bronchoscopy, and flexible bronchoscopy to evaluate the airway. Initial conservative management strategies were pursued. Patients failing initial conservative management strategies were considered for rescue bronchial stenting. RESULTS: Our initial clinical experience with a coronary bare metal stent for these procedures has been favorable. The stent was easy to deploy with precision. We did not encounter stent embolization or migration. There was sufficient stent radial strength to relieve bronchomalacia without causing restenosis or erosion. There was no significant granulation tissue formation. In one patient, the stent was removed after 12 months of somatic growth; this was uneventful and bronchial patency was maintained. There were no complications in any of our patients regarding stent placement and reliability. CONCLUSION: In cases of three infants with severe bronchomalacia, we found that bronchial stenting with the bare metal coronary stent was effective in relieving bronchial stenosis.

4D Flow MRI Quantification of Congenital Shunts: Comparison to Invasive Catheterization.

PURPOSE: To compare invasive right heart catheterization with four-dimensional (4D) flow MRI for estimating shunt fraction in patients with intracardiac and extracardiac shunts. MATERIALS AND METHODS: In this retrospective study, patients who underwent 4D flow MRI and invasive right heart catheterization with a shunt run between August 2015 and November 2018 were included. The primary objective was comparison of estimated shunt fraction (ratio of pulmonary-to-systemic flow, Qp/Qs) at 4D flow and catheterization. Secondary objectives included comparison of the right ventricular-to-left ventricular stroke volume ratio (RVSV/LVSV) to shunt fraction (for those with applicable shunts) and comparison of cardiac output between 4D flow and catheterization. Statistical analysis included Pearson correlation and Bland-Altman plots. RESULTS: A total of 33 patients met inclusion criteria (mean age, 49 years ± 16 [standard deviation]; 24 women). 4D flow measurements of Qp/Qs strongly correlated with those at catheterization (r = 0.938), and there was no bias. RVSV/LVSV correlated strongly with Qp/Qs from 4D flow (r = 0.852) and catheterization (r = 0.842). Measurements of left ventricle (Qs) and right ventricle (QP) cardiac output from 4D flow and catheterization (Fick) correlated moderately overall (r = 0.673 [Qp] and r = 0.750 [Qs]). CONCLUSION: Shunt fraction measurement using 4D flow MRI compares well with that using invasive cardiac catheterization.Supplemental material is available for this article.© RSNA, 2021.

Expanded Use of the One-Step Technique for Simultaneous Landing Zone Stenting and Placement of the Melody Transcatheter Pulmonary Valve.

OBJECTIVES: We report a multicenter experience with simultaneous right ventricular outflow tract (RVOT) stenting and transcatheter pulmonary valve implantation using the Melody valve (Medtronic). BACKGROUND: Prestenting the RVOT before Melody valve implantation is now the standard of care. Prestenting is usually performed as a separate step. The "one-step" technique for simultaneous landing zone stenting and Melody delivery was previously reported using only Max LD stents (Medtronic). We report a multicenter experience of simultaneous stenting and Melody implantation using multiple stent types in combination. METHODS: This retrospective cohort study includes 33 patients from 3 centers who underwent simultaneous stenting and Melody valve implantation between 2017 and 2020. Key variables were compared with 31 patients from the same centers who underwent standard (non-simultaneous) prestenting followed by Melody implantation during the same time frame. RESULTS: The 2 groups were similar in terms of age, weight, sex, and total procedure time. The 2 groups had similar clinical results and safety profiles, with no difference between the postimplantation right ventricle (RV) to pulmonary artery systolic pressure gradient, RV to aortic pressure ratio, and complication rate. The simultaneous group had lower radiation exposure as measured by dose area product. Up to 3 stents were safely placed simultaneously with a Melody valve. CONCLUSIONS: Simultaneous RVOT stenting and Melody valve implantation can safely be used to place up to 3 stents outside a Melody valve. This approach can simplify the catheterization procedure and potentially reduce radiation dose.