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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.

This hemodynamic feasibility study examined total cavopulmonary connection (TCPC) designs connecting the extracardiac conduit to the anterior surface of pulmonary arteries (PAs) or superior vena cava (SVC) rather than to the inferior PA surface (traditional TCPC). The study involved twenty-five consecutive Fontan patients meeting inclusion criteria from a single institution. A virtual surgical platform mimicked the completed traditional TCPC and generated three anterior anastomosis designs: Anterior-PA, Middle-SVC, and SVC-Inn (Inn: innominate vein). Hemodynamic performance of anterior anastomosis designs was compared with the traditional TCPC regarding indexed power loss (iPL) and hepatic flow distribution (HFD). Compared to the traditional TCPC, the Anterior-PA design produces a similar iPL. The Middle-SVC design is also similar, though the iPL difference is positively correlated with the anastomosing height. The SVC-Inn design had significantly more iPL. The three anterior anastomosis designs did not have a significant difference in HFD (from traditional TCPC). Pulmonary flow distribution (PFD) has a stronger correlation with HFD from the anterior anastomosis designs than the traditional TCPC. This hemodynamic feasibility study examined anterior anastomosis, extracardiac TCPC designs that may offer surgeons clinical dexterity. The Anterior-PA design may be equivalent to the traditional TCPC. Fontan extracardiac conduit anastomosis just superior to the PAs (Middle-SVC) also preserves hemodynamic performance and avoids direct PA anastomosis. These designs could simplify surgical Fontan completion, and may particularly benefit patients requiring surgical dissection, having atypical PA orientation, or after PA stent angioplasty.

Background Patent ductus arteriosus (PDA) stenting is evolving as an alternative to surgical aorto-pulmonary shunts for infants with ductal-dependent pulmonary blood flow. Given anatomical proximity, the PDA can compress the ipsilateral bronchus. We report a case series of four patients with bronchial compression by a tortuous PDA who underwent PDA stenting. Methods Our four patients received PDA stents for ductal-dependent pulmonary blood flow despite preprocedure imaging evidence of bronchial compression. We reviewed the cross-sectional chest imaging to assess the degree of bronchial compression and the variables that affect it, namely PDA size, PDA tortuosity, and the anatomical relationship between the compressed bronchus and the PDA. Results Three out of the four patients had postprocedure imaging, and all showed relief of the previously seen bronchial compression. Post-PDA stenting patients had a smaller and straight PDA with significant lateralization away from the compressed bronchus. None of the four patients developed symptoms of bronchial compression poststenting. Conclusions Our study suggests that pre-existing bronchial compression does not preclude PDA stenting. Stent placement in an engorged and tortuous PDA led to significant improvement in pre-existing bronchial compression. Improvement may be attributed to PDA shrinkage, straightening, and lateralization. Further studies are needed to confirm our findings.

In recent years, interventional cardiac magnetic resonance imaging (iCMR) has evolved from attractive theory to clinical routine at several centers. Real-time cardiac magnetic resonance imaging (CMR fluoroscopy) adds value by combining soft-tissue visualization, concurrent hemodynamic measurement, and freedom from radiation. Clinical iCMR applications are expanding because of advances in catheter devices and imaging. In the near future, iCMR promises novel procedures otherwise unsafe under standalone X-Ray guidance.

Background: Neonatal myocardial infarction is rare and is associated with a high mortality of 40% to 50%. We report our experience with neonatal myocardial infarction, including presentation, management, outcomes, and our current patient management algorithm. Methods: We reviewed all infants admitted with a diagnosis of coronary artery thrombosis, coronary ischemia, or myocardial infarction between January 2015 and May 2021. Results: We identified 21 patients (median age, 1 [interquartile range (IQR), 0.25–9.00] day; weight, 3.2 [IQR, 2.9–3.7] kg). Presentation included respiratory distress (16), shock (3), and murmur (2). Regional wall motion abnormalities by echocardiogram were a key criterion for diagnosis and were present in all 21 with varying degrees of depressed left ventricular function (severe [8], moderate [6], mild [2], and low normal [5]). Ejection fraction ranged from 20% to 54% (median, 43% [IQR, 34%–51%]). Mitral regurgitation was present in 19 (90%), left atrial dilation in 15 (71%), and pulmonary hypertension in 18 (86%). ECG was abnormal in 19 (90%). Median troponin I was 0.18 (IQR, 0.12–0.56) ng/mL. Median BNP (B-type natriuretic peptide) was 2100 (IQR, 924–2325) pg/mL. Seventeen had documented coronary thrombosis by cardiac catheterization. Seventeen (81%) were treated with intracoronary tPA (tissue-type plasminogen activator) followed by systemic heparin, AT (antithrombin), and intravenous nitroglycerin, and 4 (19%) were treated with systemic heparin, AT, and intravenous nitroglycerin alone. Nineteen of 21 recovered. One died (also had infradiaphragmatic total anomalous pulmonary venous return). One patient required a ventricular assist device and later underwent heart transplant; this patient was diagnosed late at 5 weeks of age and did not respond to tPA. Nineteen of 21 (90%) regained normal left ventricular function (ejection fraction, 60%–74%; mean, 65% [IQR, 61%–67%]) at latest follow-up (median, 6.8 [IQR, 3.58–14.72] months). Two of 21 (10%) had residual trivial mitral regurgitation. After analysis of these results, we present our current algorithm, which developed and matured over time, to manage neonatal myocardial infarction. Conclusions: We experienced a lower mortality rate for infants with neonatal infarction than that reported in the literature. We propose a post hoc algorithm that may lead to improvement in patient outcomes following coronary artery thrombus.

Purpose of Review Cardiac magnetic resonance imaging provides radiation-free, 3-dimensional soft tissue visualization with adjunct hemodynamic data, making it a promising candidate for image-guided transcatheter interventions. This review focuses on the benefits and background of real-time magnetic resonance imaging (MRI)-guided cardiac catheterization, guidance on starting a clinical program, and recent research developments. Recent Findings Interventional cardiac magnetic resonance (iCMR) has an established track record with the first entirely MRI-guided cardiac catheterization for congenital heart disease reported nearly 20 years ago. Since then, many centers have embarked upon clinical iCMR programs primarily performing diagnostic MRI-guided cardiac catheterization. There have also been limited reports of successful real-time MRI-guided transcatheter interventions. Growing experience in performing cardiac catheterization in the magnetic resonance environment has facilitated practical workflows appropriate for efficiency-focused cardiac catheterization laboratories. Most exciting developments in imaging technology, MRI-compatible equipment and MRI-guided novel transcatheter interventions have been limited to preclinical research. Many of these research developments are ready for clinical translation. Summary With increasing iCMR clinical experience and translation of preclinical research innovations, the time to make the leap to radiation-free procedures is now.

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.We reviewed our experience using IVUS as an adjunctive tool to diagnose lesions and assess intervention in pediatric patients during cardiac catheterization.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.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.

To report a single-institution's experience of symptomatic aortopulmonary collaterals presenting as tracheostomy tube hemorrhage.Retrospective case series and Contemporary Review.Tertiary care children's hospital.Retrospective review, from 2015 to 2020, of patients18 years old who were treated for tracheostomy hemorrhage with endovascular embolization of aortopulmonary collateral (APC) vessels.4 patients were identified, 2 males and 2 females, ages 15 months-to 14 years-old, with a range of cyanotic congenital heart diseases. Direct laryngoscopy and bronchoscopy were necessary for excluding proximal airway sources. Chest computed tomography angiography did not localize pulmonary hemorrhage, but helped identify aortopulmonary collaterals. Cardiac catheterization was both diagnostic and therapeutic with use of endovascular embolization techniques by pediatric interventional cardiology and interventional radiology. Previously reported APC-related pulmonary hemorrhages occurred in significantly different settings compared to our patients, and evaluation by an otolaryngologist was key to rule out upper airway etiologies.Symptomatic aortopulmonary collaterals is an important etiology in pediatric tracheostomy tube hemorrhage in patients with cyanotic congenital heart disease.

We report a multicenter experience with simultaneous right ventricular outflow tract (RVOT) stenting and transcatheter pulmonary valve implantation using the Melody valve (Medtronic).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.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.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.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.

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 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.

Background/objective Stenting the ductus arteriosus (DAS) has become an alternative to surgical systemic to pulmonary artery shunts in neonates with ductal-dependent pulmonary blood flow (PBF). Femoral approach for a vertical ductus can be difficult secondary to the acute angle and tortuous course, thus alternative access sites have been explored. Carotid access complications have been reported in 5%-10%. The extensive use of an axillary arterial approach in the United States has not been reported. The aim of this study is to describe our experience with DAS using the axillary approach. Methods We reviewed all patients with DAS with an axillary approach in neonates with ductal-dependent PBF (May 2017-May 2018) in our institution. Procedural reports, angiograms, and clinical records of all consecutive patients were reviewed. Procedural technique, procedural outcomes, adverse events, and post-hospital courses are reported. Results Seven consecutive patients who received DAS utilizing axillary approach. All patients had ductal-dependent PBF through a vertical, tortuous ductus. Five had pulmonary atresia or near atresia, one had compromised PBF due to dynamic subvalvar obstruction, and one had Tetralogy of Fallot with isolated left pulmonary artery. Axillary access with 3.3 or 4 French sheath was obtained using ultrasound guidance. Bare metal coronary stents were deployed successfully in all. Intra-procedure, one developed in stent thrombus requiring re-stenting. There were no procedural mortalities or major adverse events from axillary access. There is a steep learning curve. Hemostasis was achieved with manual compression. Two patients had reintervention at 6-8 weeks. All patients underwent successful planned surgeries. Conclusions This series suggests DAS in neonates utilizing an axillary approach is a feasible and effective alternative for establishing PBF. Axillary arterial approach may be preferred as there is no risk to neurological sequelae and very low risk of limb complications. Larger series are needed to validate this approach.

Background: Patients with heterotaxy, single ventricle and interrupted inferior vena cava are at risk of developing significant pulmonary arteriovenous malformations and cyanosis, and inequitable distribution of hepatic factor has been implicated in their development. We describe our experience with a technique for hepatic vein incorporation that reliably provides resolution of cyanosis and presumably equitable hepatic factor distribution. Methods: A retrospective review of a single-surgeon experience was conducted for patients who underwent this modified Fontan operation utilizing an extracardiac conduit from the hepatic veins to the dominant superior cavopulmonary connection. Preoperative characteristics and imaging, operative details, and postoperative course and imaging were abstracted. Results: Median age at operation was 5 years (2-10 years) and median weight was 19.6 kg (11.8-23 kg). Sixty percent (3/5) of patients had Fontan completion without cardiopulmonary bypass, and follow-up was complete at a median of 14 months (range 1-20 months). Systemic saturations increased significantly from 81% ± 1.9% preoperatively to 95% ± 3.5% postoperatively, P = .0008. Median length of stay was 10 days (range: 7-14 days). No deaths occurred. One patient required reoperation for bleeding and one was readmitted for pleural effusion. Postoperative imaging suggested distribution of hepatic factor to all lung segments with improved pulmonary arteriovenous malformation burden. Conclusions: Hepatic vein incorporation for patients with heterotaxy and interrupted inferior vena cava should optimally provide equitable pulmonary distribution of hepatic factor with resolution of cyanosis. The described technique is performed through a conventional approach, is facile, and improves cyanosis in these complex patients.

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.

Background: Ductal-dependent cyanotic newborns require a secure source of pulmonary blood flow. There has been a recent migration to selective ductal (patent ductus arteriosus [PDA]) stenting for some of these children. Universal (nonselective) ductal stenting for all infants with ductal-dependent pulmonary blood flow is controversial. We examine outcomes from a single center with this practice change. Methods: We compare outcomes of all ductal-dependent pulmonary blood flow infants (2013–2020 [January–June]) in the following treatment eras: Era 1 (selective PDA stenting; 2013–2017) or Era 2 (universal PDA stenting; 2018–2020 [January–June]). Results: Eighty-eight patients (Blalock-Taussig shunt, n=41; PDA stent, n=47) met inclusion criteria. In Era 1, most received Blalock-Taussig shunt (62% [41/66]). In Era 2, all received PDA stents (100% [22/22]). There were more females in Era 2, but otherwise no demographic differences between eras. There were no differences in mortality, treatment failures, complications, or reinterventions between eras. Postprocedure length of stay was shorter in Era 2 (8 versus 22 days, P =0.02). There were less surgical revisions for PDA stent patients (2% versus 20%, P =0.02). Postprocedure recovery surrogate end points favored Era 2 and PDA stenting. Additional analysis revealed PDA stent (compared with Blalock-Taussig shunt) patients had shorter post-procedure (10 versus 29 days, P ≤0.001) length of stay and more symmetrical branch pulmonary arteries (0.9 versus 0.7, P =0.001) at subsequent surgery. Conclusions: PDA stenting for almost all ductal dependent cyanotic newborns can be safe and effective and may have lower morbidity than selective PDA stenting.

Background: Low- and-middle-income-countries (LMICs) currently bear 80% of the world’s cardiovascular disease (CVD) mortality burden. The same countries are underequipped to handle the disease burden due to critical shortage of resources. Functional cardiac catheterization laboratories (cath labs) are central in the diagnosis and management of CVDs. Yet, most LMICs, including Uganda, fall remarkably below the minimum recommended standards of cath lab:population ratio due to a host of factors including the start-up and recurring costs. Objectives: To review the performance, challenges and solutions employed, lessons learned, and projections for the future for a single cath lab that has been serving the Ugandan population of 40 million people in the past eight years. Methods: A retrospective review of the Uganda Heart Institute cath lab clinical database from 15 February 2012 to 31 December 2019 was performed. Results: In the initial two years, this cath lab was dependent on skills transfer camps by visiting expert teams, but currently, Ugandan resident specialists independently operate this lab. 3,542 adult and pediatric procedures were conducted in 8 years, including coronary angiograms and percutaneous coronary interventions, device implantations, valvuloplasties, and cardiac defect closures, among others. There was a consistent expansion of the spectrum of procedures conducted in this cath lab each year. The initial lack of technical expertise and sourcing for equipment, as well as the continual need for sundries present(ed) major roadblocks. Government support and leveraging existing multi-level collaborations has provided a platform for several solutions. Sustainability of cath lab services remains a significant challenge especially in relation to the high cost of sundries and other consumables amidst a limited budget. Conclusion: A practical example of how centers in LMIC can set up and sustain a public cardiac catheterization laboratory is presented. Government support, research, and training collaborations, if present, become invaluable leverage opportunities.

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.

Low-profile stents placed in pediatric patients with congenital heart disease must be expanded by balloon angioplasty to accommodate patient growth. During the process of serial dilation, some stents may spontaneously fracture. The incidence and safety profile of spontaneous fracture is unclear. We report the performance characteristics and safety profile of a cohort of low-profile, premounted stents placed in the pulmonary arteries and aorta and then serially dilated over time to accommodate patient growth, including incidence of fracture and any adverse events.A retrospective chart review was conducted of 25 pediatric patients who underwent 27 stent placements with low-profile, premounted stents from January 2005 to September 2018.Nine stents (33%) sustained a spontaneous fracture. There was no statistically significant association between stent fracture and our variables of interest, ie, patient gender, patient weight at time of original stenting, stent location (aorta vs pulmonary artery), stent type, original diameter of stent, and weight at the time of stent implantation. There was no association between time to spontaneous fracture and the aforementioned variables of interest. The majority of the spontaneous fractures occurred within the first 4 years after stent implantation, and there was no difference in survival between the 3 stent types investigated in our cohort.One-third of stents undergoing serial dilation for patient growth fractured spontaneously. Patients with fractured stents were free from significant adverse events in this cohort.

A 15-year-old presented in cardiogenic shock secondary to viral myocarditis requiring venoarterial extracorporeal membrane oxygenation (ECMO) support. He developed large thrombi of the left ventricle and aortic root. Anticoagulation was increased, and medications were initiated to decrease the likelihood of aortic valve opening. He underwent balloon atrial septostomy followed by placement of a left atrial vent. A pigtail catheter was placed in the ascending aorta for direct heparin infusion. Serial echocardiograms showed progressive resolution of the thrombi. He was successfully weaned from ECMO and discharged home without neurological deficits.

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.

Background In the modern era, results of the arterial switch operation (ASO) for transposition of the great arteries are excellent. However, because of the LeCompte maneuver, there may be a propensity for development of pulmonary artery stenosis. We encountered atypical complications of pulmonary artery stenting in patients after the ASO, including aorto-pulmonary fistula and coronary compression. Methods We performed a 10-year retrospective review of catheterizations performed in patients after ASO in our institution with a focus on adverse events. Results Diagnostic and interventional catheterizations were performed in 47 patients. In 29 patients, 37 interventional procedures performed, which included pulmonary artery angioplasty and/or stenting. In this group, there were five major adverse events (14%), including three aorto-pulmonary fistulae and one coronary artery compression among patients having stent implantation or stent redilation. In addition, there were 6/37 (16%) intended stent procedures, which were aborted because there appeared to be high-risk of significant adverse events. Conclusions This review suggests that percutaneous intervention on pulmonary artery stenosis after ASO has high-risk and should be undertaken advisedly. Prior thorough evaluation of coronary arteries is mandatory as coronary reimplantation sites may be adjacent to sites of pulmonary artery stenosis. Furthermore, if pulmonary artery stent implantation or stent redilation is contemplated, the risk of stent fracture and possible AP fistula should be recognized. Primary use of reinforced covered stents should be considered.

In X-ray fluoroscopy, static overlays are used to visualize soft tissue. We propose a system for cardiac and respiratory motion compensation of these overlays. It consists of a 3-D motion model created from real-time magnetic resonance (MR) imaging. Multiple sagittal slices are acquired and retrospectively stacked to consistent 3-D volumes. Slice stacking considers cardiac information derived from the ECG and respiratory information extracted from the images. Additionally, temporal smoothness of the stacking is enhanced. Motion is estimated from the MR volumes using deformable 3-D/3-D registration. The motion model itself is a linear direct correspondence model using the same surrogate signals as slice stacking. In X-ray fluoroscopy, only the surrogate signals need to be extracted to apply the motion model and animate the overlay in real time. For evaluation, points are manually annotated in oblique MR slices and in contrast-enhanced X-ray images. The 2-D Euclidean distance of these points is reduced from 3.85 to 2.75 mm in MR and from 3.0 to 1.8 mm in X-ray compared with the static baseline. Furthermore, the motion-compensated overlays are shown qualitatively as images and videos.

Background In the care of patients with congenital heart disease, percutaneous interventional treatments have supplanted many surgical approaches for simple lesions, such as atrial septal defect. By contrast, complex congenital heart defects continue to require open-heart surgery. In single-ventricle patients, a staged approach is employed, which requires multiple open-heart surgeries and significant attendant morbidity and mortality. A nonsurgical transcatheter alternative would be attractive. Objectives The authors sought to show the feasibility of catheter-only, closed-chest, large-vessel anastomosis (superior vena cava and pulmonary artery [PA] or bidirectional Glenn operation equivalent) in a patient. Methods In preclinical testing over a decade, the authors developed the techniques and technology needed for nonsurgical crossing from a donor (superior vena cava) to a recipient (PA) vessel and endovascular stent-based anastomosis of those blood vessels. The authors undertook this transcatheter approach for an adult with untreated congenital heart disease with severe cyanosis and significant surgical risk. They rehearsed the procedure step by step using contrast-enhanced cardiac computed tomography and a patient-specific 3-dimensional printed heart model. Results The authors describe a first-in-human, fully percutaneous superior cavopulmonary anastomosis (bidirectional Glenn operation equivalent). The patient, a 35-year-old woman, was homebound due to dyspnea and worsening cyanosis. She was diagnosed with functional single ventricle and very limited pulmonary blood flow. The heart team believed surgical palliation conferred high operative risk due to the patient’s complete condition. With the percutaneous procedure, the patient recovered uneventfully and remained improved clinically after 6 months. Conclusions This procedure may provide a viable alternative to one of the foundational open-heart surgeries currently performed to treat single-ventricle congenital heart disease.

BackgroundQuantification of cardiac output and pulmonary vascular resistance (PVR) are critical components of invasive hemodynamic assessment, and can be measured concurrently with pressures using phase contrast CMR flow during real-time CMR guided cardiac catheterization.MethodsOne hundred two consecutive patients underwent CMR fluoroscopy guided right heart catheterization (RHC) with simultaneous measurement of pressure, cardiac output and pulmonary vascular resistance using CMR flow and the Fick principle for comparison. Procedural success, catheterization time and adverse events were prospectively collected.ResultsRHC was successfully completed in 97/102 (95.1%) patients without complication. Catheterization time was 20±11min. In patients with and without pulmonary hypertension, baseline mean pulmonary artery pressure was 39±12mmHg vs. 18±4mmHg (p&nbsp

Transcatheter electrosurgery refers to a family of procedures using radiofrequency energy to vaporize and traverse or lacerate tissue despite flowing blood. The authors review theory, simulations, and benchtop demonstrations of how guidewires, insulation, adjunctive catheters, and dielectric medium interact. For tissue traversal, all but the tip of traversing guidewires is insulated to concentrate current. For leaflet laceration, the "Flying V" configuration concentrates current at the inner lacerating surface of a kinked guidewire. Flooding the field with non-ionic dextrose eliminates alternative current paths. Clinical applications include traversing occlusions (pulmonary atresia, arterial and venous occlusion, and iatrogenic graft occlusion), traversing tissue planes (atrial and ventricular septal puncture, radiofrequency valve repair, transcaval access, Potts and Glenn shunts), and leaflet laceration (BASILICA, LAMPOON, ELASTA-Clip, and others). Tips are provided for optimizing these techniques. Transcatheter electrosurgery already enables a range of novel therapeutic procedures for structural heart disease, and represents a promising advance toward transcatheter surgery.

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.

Stenosis, or narrowing, of the branches of the pulmonary artery is a type of CHD that, if left untreated, may lead to significant complications. Ideally, interventions to treat stenosis occur before significant complications or long-term sequelae take place, often within the first 2 years of life. Treatment depends on specifics of the condition, the presence of other malformations, and age of the child. Research and recent innovation to address these shortcomings have provided physicians with safer and more effective methods of treatment. This has further continued to push the ceiling of pulmonary arterial stenosis treatment available for patients. Despite continuous advancement in angioplasty – such as conventional and cutting balloon – and stenting, each treatment method is not without its unique limitations. New technological developments such as bioresorbable stents can accommodate patient growth and pulmonary artery stenosis treatment. As more than a decade has passed since the review by Bergersen and Lock, this article aims to provide a contemporary summary and investigation into the effectiveness of various therapeutic tools currently available, such as bare metal stents and potential innovations including bioresorbable stents.

Objectives To determine whether X-ray fused with MRI (XFM) is beneficial for select transcatheter congenital heart disease interventions. Background Complex transcatheter interventions often require three-dimensional (3D) soft tissue imaging guidance. Fusion imaging with live X-ray fluoroscopy can potentially improve and simplify procedures. Methods Patients referred for select congenital heart disease interventions were prospectively enrolled. Cardiac MRI data was overlaid on live fluoroscopy for procedural guidance. Likert scale operator assessments of value were recorded. Fluoroscopy time, radiation exposure, contrast dose, and procedure time were compared to matched cases from our institutional experience. Results Forty-six patients were enrolled. Pre-catheterization, same day cardiac MRI findings indicated intervention should be deferred in nine patients. XFM-guided cardiac catheterization was performed in 37 (median age 8.7 years [0.5-63 years]; median weight 28 kg [5.6-110 kg]) with the following prespecified indications: pulmonary artery (PA) stenosis (n = 13), aortic coarctation (n = 12), conduit stenosis/insufficiency (n = 9), and ventricular septal defect (n = 3). Diagnostic catheterization showed intervention was not indicated in 12 additional cases. XFM-guided intervention was performed in the remaining 25. Fluoroscopy time was shorter for XFM-guided intervention cases compared to matched controls. There was no significant difference in radiation dose area product, contrast volume, or procedure time. Operator Likert scores indicated XFM provided useful soft tissue guidance in all cases and was never misleading. Conclusions XFM provides operators with meaningful three-dimensional soft tissue data and reduces fluoroscopy time in select congenital heart disease interventions.

BACKGROUND: Cardiac magnetic resonance (MR) imaging is a valuable tool in congenital heart disease; however patients frequently have metal devices in the chest from the treatment of their disease that complicate imaging. Methods are needed to improve imaging around metal implants near the heart. Basic sequence parameter manipulations have the potential to minimize artifact while limiting effects on image resolution and quality. OBJECTIVE: Our objective was to design cine and static cardiac imaging sequences to minimize metal artifact while maintaining image quality. MATERIALS AND METHODS: Using systematic variation of standard imaging parameters on a fluid-filled phantom containing commonly used metal cardiac devices, we developed optimized sequences for steady-state free precession (SSFP), gradient recalled echo (GRE) cine imaging, and turbo spin-echo (TSE) black-blood imaging. We imaged 17 consecutive patients undergoing routine cardiac MR with 25 metal implants of various origins using both standard and optimized imaging protocols for a given slice position. We rated images for quality and metal artifact size by measuring metal artifact in two orthogonal planes within the image. RESULTS: All metal artifacts were reduced with optimized imaging. The average metal artifact reduction for the optimized SSFP cine was 1.5+/−1.8 mm, and for the optimized GRE cine the reduction was 4.6+/−4.5 mm (P

Background Children with heart disease may require repeated X-Ray cardiac catheterization procedures, are more radiosensitive, and more likely to survive to experience oncologic risks of medical radiation. Cardiovascular magnetic resonance (CMR) is radiation-free and offers information about structure, function, and perfusion but not hemodynamics. We intend to perform complete radiation-free diagnostic right heart catheterization entirely using CMR fluoroscopy guidance in an unselected cohort of pediatric patients; we report the feasibility and safety. Methods We performed 50 CMR fluoroscopy guided comprehensive transfemoral right heart catheterizations in 39 pediatric (12.7 ± 4.7 years) subjects referred for clinically indicated cardiac catheterization. CMR guided catheterizations were assessed by completion (success/failure), procedure time, and safety events (catheterization, anesthesia). Pre and post CMR body temperature was recorded. Concurrent invasive hemodynamic and diagnostic CMR data were collected. Results During a twenty-two month period (3/2015 – 12/2016), enrolled subjects had the following clinical indications: post-heart transplant 33%, shunt 28%, pulmonary hypertension 18%, cardiomyopathy 15%, valvular heart disease 3%, and other 3%. Radiation-free CMR guided right heart catheterization attempts were all successful using passive catheters. In two subjects with septal defects, right and left heart catheterization were performed. There were no complications. One subject had six such procedures. Most subjects (51%) had undergone multiple (5.5 ± 5) previous X-Ray cardiac catheterizations. Retained thoracic surgical or transcatheter implants (36%) did not preclude successful CMR fluoroscopy heart catheterization. During the procedure, two subjects were receiving vasopressor infusions at baseline because of poor cardiac function, and in ten procedures, multiple hemodynamic conditions were tested. Conclusions Comprehensive CMR fluoroscopy guided right heart catheterization was feasible and safe in this small cohort of pediatric subjects. This includes subjects with previous metallic implants, those requiring continuous vasopressor medication infusions, and those requiring pharmacologic provocation. Children requiring multiple, serial X-Ray cardiac catheterizations may benefit most from radiation sparing. This is a step toward wholly CMR guided diagnostic (right and left heart) cardiac catheterization and future CMR guided cardiac intervention. Trial registration ClinicalTrials.gov NCT02739087 registered February 17, 2016 Electronic supplementary material The online version of this article (doi:10.1186/s12968-017-0374-2) contains supplementary material, which is available to authorized users.

Renal artery stenosis (RAS) accounts for 10 % of cases of systemic hypertension in children. Initial management involves anti-hypertensive therapy. Percutaneous interventions are documented for the treatment of RAS in the adult population. In children, case reports suggest benefit.This is a retrospective analysis of consecutive patients referred for catheterization for RAS between 2002 and 2010 at a single institution. Recorded variables included: age, weight, systemic blood pressure, minimal luminal diameter, interventional devices, antihypertensive medications, contrast volume, and complications.Twelve patients (median age 8.2, IQR 6-12.4 years); median weight 42.8 kg, IQR: 25-47.4 kg) were referred for renal artery catheterization and underwent percutaneous intervention. Overall, minimal luminal diameter (MLD) increased by 1.2 ± 0.9 mm for all patients (p 0.05) and by 1.3 ± 0.9 mm for post-renal transplant patients (p 0.05). Only stent angioplasty patients demonstrated significant improved blood pressure (p 0.05). One patient had stent thrombosis requiring re-intervention with repeat balloon angioplasty.This retrospective analysis suggests that percutaneous intervention might play a role in the management of RAS, with an improvement in MLD in children with RAS. Transcatheter intervention is technically feasible with low morbidity. A prospective, longitudinal study is warranted to compare standard medical therapy with percutaneous interventions.

Improvements in fetal echocardiography have increased recognition of fetuses with congenital heart disease (CHD) that require specialized delivery room (DR) care. In this study, care protocols for these low-volume and high-risk deliveries were created. Elements included (1) diagnosis-specific DR care plans and algorithms, (2) a multidisciplinary team with expertise, (3) simulation, (4) checklists, and (5) debriefing. The purpose of this study was to assess the accuracy of fetal echocardiography to predict the need for specialized DR care and determine the effectiveness of the care protocols for the treatment of patients with critical CHD. Fetal and postnatal medical records and echocardiograms of fetuses with CHD assigned to an advanced level of care were reviewed. Safety and outcome variables were analyzed to determine care plan and algorithm efficacy. Thirty-four fetuses were identified: 12 delivered at Children's National Medical Center and 22 at the adult hospital. Diagnoses included hypoplastic left heart syndrome, aortic stenosis, d-transposition of the great arteries, tetralogy of Fallot with absent pulmonary valve, complex pulmonary atresia, arrhythmias, ectopia cordis, and conjoined twins. Delivery at Children's National Medical Center was associated with a shorter time to specialty care or intervention. Measures of physiologic stability and survival were similar. Need for specialized care was predicted in 84% of deliveries. For hypoplastic left heart syndrome, intervention was predicted in 10 of 11 deliveries and for d-transposition of the great arteries in 10 of 12 deliveries. Care algorithms addressed most DR events. Of the unanticipated events, none were unrecoverable. DR survival was 100%, and survival to discharge was 83%. In conclusion, fetal echocardiography predicted the need for specialized DR care in fetuses with critical CHD. Algorithm-driven protocols enable planning such that maternal and infant risk is minimized and outcomes are good.

Arrhythmia ablation with current techniques is not universally successful. Inadequate ablation lesion formation may be responsible for some arrhythmia recurrences. Periprocedural visualization of ablation lesions may identify inadequate lesions and gaps to guide further ablation and reduce risk of arrhythmia recurrence.This feasibility study assessed acute postprocedure ablation lesions by MRI, and correlated these findings with clinical outcomes. Ten pediatric patients who underwent ventricular tachycardia ablation were transferred immediately postablation to a 1.5T MRI scanner and late gadolinium enhancement (LGE) imaging was performed to characterize ablation lesions. Immediate and mid-term arrhythmia recurrences were assessed.Patient characteristics include median age 14 years (1-18 years), median weight 52 kg (11-81 kg), normal cardiac anatomy (n = 6), d-transposition of great arteries post arterial switch repair (n = 2), anomalous coronary artery origin post repair (n = 1), and cardiac rhabdomyoma (n = 1). All patients underwent radiofrequency catheter ablation of ventricular arrhythmia with acute procedural success. LGE was identified at the reported ablation site in 9/10 patients, all arrhythmia-free at median 7 months follow-up. LGE was not visible in 1 patient who had recurrence of frequent premature ventricular contractions within 2 hours, confirmed on Holter at 1 and 21 months post procedure.Ventricular ablation lesion visibility by MRI in the acute post procedure setting is feasible. Lesions identifiable with MRI may correlate with clinical outcomes. Acute MRI identification of gaps or inadequate lesions may provide the unique temporal opportunity for additional ablation therapy to decrease arrhythmia recurrence.

Objectives The aim of this study was to test the hypothesis that real-time magnetic resonance imaging (MRI) would enable closed-chest percutaneous cavopulmonary anastomosis and shunt by facilitating needle guidance along a curvilinear trajectory, around critical structures, and between a superior vena cava “donor” vessel and a pulmonary artery “target.” Background Children with single-ventricle physiology require multiple open heart operations for palliation, including sternotomies and cardiopulmonary bypass. The reduced morbidity of a catheter-based approach would be attractive. Methods Fifteen naive swine underwent transcatheter cavopulmonary anastomosis and shunt creation under 1.5-T MRI guidance. An MRI antenna-needle was advanced from the superior vena cava into the target pulmonary artery bifurcation using real-time MRI guidance. In 10 animals, balloon-expanded off-the-shelf endografts secured a proximal end-to-end caval anastomosis and a distal end-to-side pulmonary anastomosis that preserved blood flow to both branch pulmonary arteries. In 5 animals, this was achieved with a novel, purpose-built, self-expanding device. Results Real-time MRI needle access of target vessels (pulmonary artery), endograft delivery, and superior vena cava shunt to pulmonary arteries were successful in all animals. All survived the procedure without complications. Intraprocedural real-time MRI, post-procedural MRI, x-ray angiography, computed tomography, and necropsy showed patent shunts with bidirectional pulmonary artery blood flow. Conclusions MRI guidance enabled a complex, closed-chest, beating-heart, pediatric, transcatheter structural heart procedure. In this study, MRI guided trajectory planning and reproducible, reliable bidirectional cavopulmonary shunt creation.

Real-time MRI creates images with superb tissue contrast that may enable radiation-free catheterization. Simple procedures are the first step towards novel interventional procedures. We aim to perform comprehensive transfemoral diagnostic right heart catheterization in an unselected cohort of patients entirely using MRI guidance.We performed X-ray and MRI-guided transfemoral right heart catheterization in consecutive patients undergoing clinical cardiac catheterization. We sampled both cavae and both pulmonary arteries. We compared success rate, time to perform key steps, and catheter visibility among X-ray and MRI procedures using air-filled or gadolinium-filled balloon-tipped catheters. Sixteen subjects (four with shunt, nine with coronary artery disease, three with other) underwent paired X-ray and MRI catheterization. Complete guidewire-free catheterization was possible in 15 of 16 under both. MRI using gadolinium-filled balloons was at least as successful as X-ray in all procedure steps, more successful than MRI using air-filled balloons, and better than both in entering the left pulmonary artery. Total catheterization time and individual procedure steps required approximately the same amount of time irrespective of image guidance modality. Catheter conspicuity was best under X-ray and next-best using gadolinium-filled MRI balloons.In this early experience, comprehensive transfemoral right heart catheterization appears feasible using only MRI for imaging guidance. Gadolinium-filled balloon catheters were more conspicuous than air-filled ones. Further workflow and device enhancement are necessary for clinical adoption.

Purpose: To develop an active delivery system that enhances visualization of nitinol cardiac occluder devices during deployment under real-time magnetic resonance imaging (MRI). Materials and Methods: We constructed an active delivery cable incorporating a loopless antenna and a custom titanium microscrew to secure the occluder devices. The delivery cable was tuned and matched to 50Ω at 64 MHz with the occluder device attached. We used real-time balanced steady state free precession in a wide-bore 1.5T scanner. Device-related images were reconstructed separately and combined with surface-coil images. The delivery cable was tested in vitro in a phantom and in vivo in swine using a variety of nitinol cardiac occluder devices. Results: In vitro, the active delivery cable provided little signal when the occluder device was detached and maximal signal with the device attached. In vivo, signal from the active delivery cable enabled clear visualization of occluder device during positioning and deployment. Device release resulted in decreased signal from the active cable. Postmortem examination confirmed proper device placement. Conclusion: The active delivery cable enhanced the MRI depiction of nitinol cardiac occluder devices during positioning and deployment, both in conventional and novel applications. We expect enhanced visibility to contribute to the effectiveness and safety of new and emerging MRI-guided treatments. J. Magn. Reson. Imaging 2012;36:972–978. © 2012 Wiley Periodicals, Inc.

Carbon monoxide (CO) has been detected within anaesthesia breathing systems. One potential source in this setting is exhaled endogenous CO. We hypothesized that CO is re-breathed during low-flow anaesthesia (LFA) in infants and children.Twenty children (age 2 months-7 yr) undergoing general anaesthesia were evaluated in a prospective observation study. LFA was established for 60 min followed by high-flow anaesthesia (HFA) for the next 60 min. Exhaled and inspired CO were measured every 5 min within the breathing circuit. Carboxyhaemoglobin (COHb%) was measured at baseline, at 60 min, after LFA, and at 120 min, after HFA.CO concentrations increased during LFA. Inspired CO peaked at 14 ppm. During HFA, exhaled CO levels remained constant whereas inspired CO decreased markedly. Exhaled and inspired CO during HFA differed significantly from LFA. The trajectory of change in exhaled and inspired CO was most closely associated with the fresh-gas flow (FGF):minute ventilation ratio. COHb% significantly increased in children2 yr of age at 60 min after LFA and remained increased.LFA increased exhaled and inspired CO and increased COHb% in children2 yr of age. Thus, LFA resulted in re-breathing of exhaled CO and exposure, especially in the youngest children. Re-breathing exhaled gas during LFA could pose a risk for an acute CO exposure in patients who have elevated COHb and high baseline levels of exhaled CO. If practitioners match or exceed minute ventilation with FGF to avoid LFA, CO re-breathing can be limited.

BACKGROUND: Carbon monoxide (CO) can be produced in the anesthesia circuit when inhaled anesthetics are degraded by dried carbon dioxide absorbent and exhaled CO can potentially be rebreathed during low-flow anesthesia. Exposure to low concentrations of CO (12.5 ppm) can cause neurotoxicity in the developing brain and may lead to neurodevelopmental impairment. In this study, we aimed to quantify the amount of CO present within a circle system breathing circuit during general endotracheal anesthesia in infants and children with fresh strong metal alkali carbon dioxide absorbent and define the variables associated with the levels detected. METHODS: Fifteen infants and children (aged 4 months to 8 years) undergoing mask induction followed by general endotracheal anesthesia were evaluated in this observational study. CO was measured in real time from the inspiratory limb of the anesthesia circuit every 5 minutes for 1 hour during general anesthesia. Carboxyhemoglobin (COHb) levels were measured at the 1-hour time point and compared with baseline. RESULTS: CO was detected in all patients older than 2 years (0-18 ppm, mean 3.7 +/- 4.8 ppm) and rarely detected in patients younger than 2 years (0-2 ppm, mean 0.2 +/- 0.6 ppm). Only the relationship between CO concentration and fresh gas flow to minute ventilation ratio (FGF:(.)VE) remained significant after adjustment in longitudinal regression analysis (P < 0.001). Although not powered to determine such a relationship, CO levels were weakly associated with the use of desflurane and female sex. There was no significant association between CO concentration and anesthetic concentration. Baseline COHb levels were higher in children younger than 2 years and decreased significantly at the 1-hour time point compared with baseline and children older than 2 years. However, COHb levels increased significantly from baseline in a predictable manner consistent with CO exposure in children older than 2 years. FGF:(.)VE correlated significantly with change in COHb using simple linear regression (r = 0.62; P < 0.02). CONCLUSIONS: CO was detected routinely during general anesthesia in infants and children when FGF:(.)VE was

A 16-year-old boy with a double-outlet right ventricle, D-malposed great vessels, and a subpulmonary ventricular septal defect status-post surgical ventricular septal defect patch closure and arterial switch procedure at 2 months of age, reported progressive exercise intolerance. He was found to have moderate right atrial enlargement, mild dilation of right and left ventricles, and a persistent residual left ventricle to right atrium (LV-RA) intracardiac shunt on echocardiographic assessment (similar physiology to a Gerbode-type defect; Figure A and Movie I in the online-only Data Supplement). Cardiac MRI delineated the LV-RA shunt (steady-state free precession cine; Figure B and Movie I in the online-only Data Supplement), with an estimated Qp:Qs of 1.4:1 (velocity-encoded MRI). Cardiac MRI–derived left-ventricular end-diastolic volume was 132 mL/m2 ( z score …

Background— Percutaneous access for mitral interventions is currently limited to transapical and transseptal routes, both of which have shortcomings. We hypothesized that the left atrium could be accessed directly through the posterior chest wall under imaging guidance. Methods and Results— We tested percutaneous transthoracic left atrial access in 12 animals (10 pigs and 2 sheep) under real-time magnetic resonance imaging or x-ray fluoroscopy plus C-arm computed tomographic guidance. The pleural space was insufflated with CO 2 to displace the lung, an 18F sheath was delivered to the left atrium, and the left atrial port was closed using an off-the-shelf nitinol cardiac occluder. Animals were survived for a minimum of 7 days. The left atrial was accessed, and the port was closed successfully in 12/12 animals. There was no procedural mortality and only 1 hemodynamically insignificant pericardial effusion was observed at follow-up. We also successfully performed the procedure on 3 human cadavers. A simulated trajectory to the left atrium was present in all of 10 human cardiac computed tomographic angiograms analyzed. Conclusions— Percutaneous transthoracic left atrial access is feasible without instrumenting the left ventricular myocardium. In our experience, magnetic resonance imaging offers superb visualization of anatomic structures with the ability to monitor and address complications in real-time, although x-ray guidance seems feasible. Clinical translation seems realistic based on human cardiac computed tomographic analysis and cadaver testing. This technique could provide a direct nonsurgical access route for future transcatheter mitral implantation.

A 12-year-old male presented with a 6-week history of apparent digital vasculitis with color changes of the distal fingers and erythematous macules of the palms and soles. Physical examination revealed skin findings of Carney complex and an abnormal cardiac examination. Echocardiography demonstrated a large left atrial mass, which caused partial obstruction during diastole and moderate mitral valve insufficiency. Surgical excision and pathological examination of the mass confirmed the presence of a large, peduculated myxoma. This case illustrates the presentation of Carney complex with left atrial myxoma as apparent vasculitis and Raynaud's phenomenon.

Diagnosis and prognostication in patients with complex cardiopulmonary disease can be a clinical challenge. A new procedure, MRI catheterization, involves invasive right-sided heart catheterization performed inside the MRI scanner using MRI instead of traditional radiographic fluoroscopic guidance. MRI catheterization combines simultaneous invasive hemodynamic and MRI functional assessment in a single radiation-free procedure. By combining both modalities, the many individual limitations of invasive catheterization and noninvasive imaging can be overcome, and additional clinical questions can be addressed. Today, MRI catheterization is a clinical reality in specialist centers in the United States and Europe. Advances in medical device design for the MRI environment will enable not only diagnostic but also interventional MRI procedures to be performed within the next few years.

Patients with single ventricle congenital heart disease often form aortopulmonary collateral vessels via an unclear mechanism. To gain insights into the pathogenesis of aortopulmonary collateral vessels, we correlated angiogenic factor levels with in vitro activity and angiographic aortopulmonary collateral assessment and examined whether patients with single ventricle physiology have increased angiogenic factors that can stimulate endothelial cell sprouting in vitro.In patients with single ventricle physiology (n = 27) and biventricular acyanotic control patients (n = 21), hypoxia-inducible angiogenic factor levels were measured in femoral venous and arterial plasma at cardiac catheterization. To assess plasma angiogenic activity, we used a 3-dimensional in vitro cell sprouting assay that recapitulates angiogenic sprouting. Aortopulmonary collateral angiograms were graded using a 4-point scale.Compared with controls, patients with single ventricle physiology had increased vascular endothelial growth factor (artery: 58.7 ± 1.2 pg/mL vs 35.3 ± 1.1 pg/mL, P.01; vein: 34.8 ± 1.1 pg/mL vs 21 ± 1.2 pg/mL, P.03), stromal-derived factor 1-alpha (artery: 1901.6 ± 1.1 pg/mL vs 1542.6 ± 1.1 pg/mL, P.03; vein: 2092.8 pg/mL ± 1.1 vs 1752.9 ± 1.1 pg/mL, P.02), and increased arterial soluble fms-like tyrosine kinase-1, a regulatory vascular endothelial growth factor receptor (612.3 ± 1.2 pg/mL vs 243.1 ± 1.2 pg/mL, P.003). Plasma factors and sprout formation correlated poorly with aortopulmonary collateral severity.We are the first to correlate plasma angiogenic factor levels with angiography and in vitro angiogenic activity in patients with single ventricle disease with aortopulmonary collaterals. Patients with single ventricle disease have increased stromal-derived factor 1-alpha and soluble fms-like tyrosine kinase-1, and their roles in aortopulmonary collateral formation require further investigation. Plasma factors and angiogenic activity correlate poorly with aortopulmonary collateral severity in patients with single ventricles, suggesting complex mechanisms of angiogenesis.

Background We aim to deliver large appliances into the left ventricle through the right ventricle and across the interventricular septum. This transthoracic access route exploits immediate recoil of the septum, and lower transmyocardial pressure gradient across the right versus left ventricular free wall. The route may enhance safety and allow subxiphoid rather than intercostal traversal. Methods The entire procedure was performed under real-time CMR guidance. An “active” CMR needle crossed the chest, right ventricular free wall, and then the interventricular septum to deliver a guidewire then used to deliver an 18Fr introducer. Afterwards, the right ventricular free wall was closed with a nitinol occluder. Immediate closure and late healing of the unrepaired septum and free wall were assessed by oximetry, angiography, CMR, and necropsy up to four weeks afterwards. Results The procedure was successful in 9 of 11 pigs. One failed because of refractory ventricular fibrillation upon needle entry, and the other because of inadequate guidewire support. In all ten attempts, the right ventricular free wall was closed without hemopericardium. There was neither immediate nor late shunt on oximetry, X-ray angiography, or CMR. The interventricular septal tract fibrosed completely. Transventricular trajectories planned on human CT scans suggest comparable intracavitary working space and less acute entry angles than a conventional atrial transseptal approach. Conclusion Large closed-chest access ports can be introduced across the right ventricular free wall and interventricular septum into the left ventricle. The septum recoils immediately and heals completely without repair. A nitinol occluder immediately seals the right ventricular wall. The entry angle is more favorable to introduce, for example, prosthetic mitral valves than a conventional atrial transseptal approach.

In magnetic resonance imaging-guided cardiovascular interventional procedures, it is valuable to be able to visualize blood flow immediately and interactively in selected regions. In particular, it is useful to assess normal or pathological communications between specific heart chambers and vessels. Phase-contrast velocity mapping is not suitable for this purpose as it requires too much data and is not capable of determining directly if blood originating in one location travels to a nearby location. This article presents a novel flow visualization method called virtual dye angiography that enables visualization of blood flow analogous to selective catheter angiography. The method uses two-dimensional radio frequency pulses to achieve interactive, intermittent, targeted saturation of a localized region of the blood pool. The flow of the saturated spins is observed directly on real-time images or, in an enhanced manner, using ECG synchronized background subtraction. The modular nature of the technique allows for easy and seamless integration into a real-time, interactive imaging system with minimal overhead. We present initial results in animals and in a healthy human volunteer.

The often touted advantages of MR guidance remain largely unrealized for cardiovascular interventional procedures in patients. Many procedures have been simulated in animal models. We argue these opportunities for clinical interventional MR will be met in the near future. This paper reviews technical and clinical considerations and offers advice on how to implement a clinical-grade interventional cardiovascular MR (iCMR) laboratory. We caution that this reflects our personal view of the "state of the art."