3D Imaging Reveals Complex Microvascular Remodeling in the Right Ventricle in Pulmonary Hypertension.

BACKGROUND: Pathogenic concepts of right ventricular (RV) failure in pulmonary arterial hypertension focus on a critical loss of microvasculature. However, the methods underpinning prior studies did not take into account the 3-dimensional (3D) aspects of cardiac tissue, making accurate quantification difficult. We applied deep-tissue imaging to the pressure-overloaded RV to uncover the 3D properties of the microvascular network and determine whether deficient microvascular adaptation contributes to RV failure. METHODS: Heart sections measuring 250-µm-thick were obtained from mice after pulmonary artery banding (PAB) or debanding PAB surgery and properties of the RV microvascular network were assessed using 3D imaging and quantification. Human heart tissues harvested at the time of transplantation from pulmonary arterial hypertension cases were compared with tissues from control cases with normal RV function. RESULTS: Longitudinal 3D assessment of PAB mouse hearts uncovered complex microvascular remodeling characterized by tortuous, shorter, thicker, highly branched vessels, and overall preserved microvascular density. This remodeling process was reversible in debanding PAB mice in which the RV function recovers over time. The remodeled microvasculature tightly wrapped around the hypertrophied cardiomyocytes to maintain a stable contact surface to cardiomyocytes as an adaptation to RV pressure overload, even in end-stage RV failure. However, microvasculature-cardiomyocyte contact was impaired in areas with interstitial fibrosis where cardiomyocytes displayed signs of hypoxia. Similar to PAB animals, microvascular density in the RV was preserved in patients with end-stage pulmonary arterial hypertension, and microvascular architectural changes appeared to vary by etiology, with patients with pulmonary veno-occlusive disease displaying a lack of microvascular complexity with uniformly short segments. CONCLUSIONS: 3D deep tissue imaging of the failing RV in PAB mice, pulmonary hypertension rats, and patients with pulmonary arterial hypertension reveals complex microvascular changes to preserve the microvascular density and maintain a stable microvascular-cardiomyocyte contact. Our studies provide a novel framework to understand microvascular adaptation in the pressure-overloaded RV that focuses on cell-cell interaction and goes beyond the concept of capillary rarefaction.

Image2Flow: A proof-of-concept hybrid image and graph convolutional neural network for rapid patient-specific pulmonary artery segmentation and CFD flow field calculation from 3D cardiac MRI data.

Computational fluid dynamics (CFD) can be used for non-invasive evaluation of hemodynamics. However, its routine use is limited by labor-intensive manual segmentation, CFD mesh creation, and time-consuming simulation. This study aims to train a deep learning model to both generate patient-specific volume-meshes of the pulmonary artery from 3D cardiac MRI data and directly estimate CFD flow fields. This proof-of-concept study used 135 3D cardiac MRIs from both a public and private dataset. The pulmonary arteries in the MRIs were manually segmented and converted into volume-meshes. CFD simulations were performed on ground truth meshes and interpolated onto point-point correspondent meshes to create the ground truth dataset. The dataset was split 110/10/15 for training, validation, and testing. Image2Flow, a hybrid image and graph convolutional neural network, was trained to transform a pulmonary artery template to patient-specific anatomy and CFD values, taking a specific inlet velocity as an additional input. Image2Flow was evaluated in terms of segmentation, and the accuracy of predicted CFD was assessed using node-wise comparisons. In addition, the ability of Image2Flow to respond to increasing inlet velocities was also evaluated. Image2Flow achieved excellent segmentation accuracy with a median Dice score of 0.91 (IQR: 0.86-0.92). The median node-wise normalized absolute error for pressure and velocity magnitude was 11.75% (IQR: 9.60-15.30%) and 9.90% (IQR: 8.47-11.90), respectively. Image2Flow also showed an expected response to increased inlet velocities with increasing pressure and velocity values. This proof-of-concept study has shown that it is possible to simultaneously perform patient-specific volume-mesh based segmentation and pressure and flow field estimation using Image2Flow. Image2Flow completes segmentation and CFD in ~330ms, which is ~5000 times faster than manual methods, making it more feasible in a clinical environment.

Computational framework for the generation of one-dimensional vascular models accounting for uncertainty in networks extracted from medical images.

One-dimensional (1D) cardiovascular models offer a non-invasive method to answer medical questions, including predictions of wave-reflection, shear stress, functional flow reserve, vascular resistance and compliance. This model type can predict patient-specific outcomes by solving 1D fluid dynamics equations in geometric networks extracted from medical images. However, the inherent uncertainty in in vivo imaging introduces variability in network size and vessel dimensions, affecting haemodynamic predictions. Understanding the influence of variation in image-derived properties is essential to assess the fidelity of model predictions. Numerous programs exist to render three-dimensional surfaces and construct vessel centrelines. Still, there is no exact way to generate vascular trees from the centrelines while accounting for uncertainty in data. This study introduces an innovative framework employing statistical change point analysis to generate labelled trees that encode vessel dimensions and their associated uncertainty from medical images. To test this framework, we explore the impact of uncertainty in 1D haemodynamic predictions in a systemic and pulmonary arterial network. Simulations explore haemodynamic variations resulting from changes in vessel dimensions and segmentation; the latter is achieved by analysing multiple segmentations of the same images. Results demonstrate the importance of accurately defining vessel radii and lengths when generating high-fidelity patient-specific haemodynamics models. KEY POINTS: This study introduces novel algorithms for generating labelled directed trees from medical images, focusing on accurate junction node placement and radius extraction using change points to provide haemodynamic predictions with uncertainty within expected measurement error. Geometric features, such as vessel dimension (length and radius) and network size, significantly impact pressure and flow predictions in both pulmonary and aortic arterial networks. Standardizing networks to a consistent number of vessels is crucial for meaningful comparisons and decreases haemodynamic uncertainty. Change points are valuable to understanding structural transitions in vascular data, providing an automated and efficient way to detect shifts in vessel characteristics and ensure reliable extraction of representative vessel radii.

Longitudinal Follow-Up of Children With HLHS and Association Between Norwood Shunt Type and Long-Term Outcomes: The SVR III Study.

OBJECTIVE: In the SVR trial (Single Ventricle Reconstruction), newborns with hypoplastic left heart syndrome were randomly assigned to receive a modified Blalock-Taussig-Thomas shunt (mBTTS) or a right ventricle-to-pulmonary artery shunt (RVPAS) at Norwood operation. Transplant-free survival was superior in the RVPAS group at 1 year, but no longer differed by treatment group at 6 years; both treatment groups had accumulated important morbidities. In the third follow-up of this cohort (SVRIII [Long-Term Outcomes of Children With Hypoplastic Left Heart Syndrome and the Impact of Norwood Shunt Type]), we measured longitudinal outcomes and their risk factors through 12 years of age. METHODS: Annual medical history was collected through record review and telephone interviews. Cardiac magnetic resonance imaging (CMR), echocardiogram, and cycle ergometry cardiopulmonary exercise tests were performed at 10 through 14 years of age among participants with Fontan physiology. Differences in transplant-free survival and complication rates (eg, arrhythmias or protein-losing enteropathy) were identified through 12 years of age. The primary study outcome was right ventricular ejection fraction (RVEF) by CMR, and primary analyses were according to shunt type received. Multivariable linear and Cox regression models were created for RVEF by CMR and post-Fontan transplant-free survival. RESULTS: Among 549 participants enrolled in SVR, 237 of 313 (76%; 60.7% male) transplant-free survivors (mBTTS, 105 of 147; RVPAS, 129 of 161; both, 3 of 5) participated in SVRIII. RVEF by CMR was similar in the shunt groups (RVPAS, 51±9.6 [n=90], and mBTTS, 52±7.4 [n=75]; P=0.43). The RVPAS and mBTTS groups did not differ in transplant-free survival by 12 years of age (163 of 277 [59%] versus 144 of 267 [54%], respectively; P=0.11), percentage predicted peak Vo2 for age and sex (74±18% [n=91] versus 72±18% [n=84]; P=0.71), or percentage predicted work rate for size and sex (65±20% versus 64±19%; P=0.65). The RVPAS versus mBTTS group had a higher cumulative incidence of protein-losing enteropathy (5% versus 2%; P=0.04) and of catheter interventions (14 versus 10 per 100 patient-years; P=0.01), but had similar rates of other complications. CONCLUSIONS: By 12 years after the Norwood operation, shunt type has minimal association with RVEF, peak Vo2, complication rates, and transplant-free survival. RVEF is preserved among the subgroup of survivors who underwent CMR assessment. Low transplant-free survival, poor exercise performance, and accruing morbidities highlight the need for innovative strategies to improve long-term outcomes in patients with hypoplastic left heart syndrome. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT0245531.

Inline automatic quality control of 2D phase-contrast flow MRI for subject-specific scan time adaptation.

PURPOSE: To develop an inline automatic quality control to achieve consistent diagnostic image quality with subject-specific scan time, and to demonstrate this method for 2D phase-contrast flow MRI to reach a predetermined SNR. METHODS: We designed a closed-loop feedback framework between image reconstruction and data acquisition to intermittently check SNR (every 20 s) and automatically stop the acquisition when a target SNR is achieved. A free-breathing 2D pseudo-golden-angle spiral phase-contrast sequence was modified to listen for image-quality messages from the reconstructions. Ten healthy volunteers and 1 patient were imaged at 0.55 T. Target SNR was selected based on retrospective analysis of cardiac output error, and performance of the automatic SNR-driven "stop" was assessed inline. RESULTS: SNR calculation and automated segmentation was feasible within 20 s with inline deployment. The SNR-driven acquisition time was 2 min 39 s ± 67 s (aorta) and 3 min ± 80 s (main pulmonary artery) with a min/max acquisition time of 1 min 43 s/4 min 52 s (aorta) and 1 min 43 s/5 min 50 s (main pulmonary artery) across 6 healthy volunteers, while ensuring a diagnostic measurement with relative absolute error in quantitative flow measurement lower than 2.1% (aorta) and 6.3% (main pulmonary artery). CONCLUSION: The inline quality control enables subject-specific optimized scan times while ensuring consistent diagnostic image quality. The distribution of automated stopping times across the population revealed the value of a subject-specific scan time.

Shape of Pulmonary Artery Doppler Flow Profile and Right Ventricular Hemodynamics in Neonates.

OBJECTIVES: To characterize pulmonary artery Doppler flow profile (PAFP) patterns among infants receiving care in neonatal intensive care units and to examine the association of PAFP patterns with pulmonary and right ventricular (RV) hemodynamics. STUDY DESIGN: This is a retrospective study at 2 tertiary intensive care units over 4 years that included neonates who demonstrated a complete tricuspid regurgitation envelope on targeted neonatal echocardiography. Separate personnel reviewed TNEs to characterize PAFP patterns, divide cohort into PAFP groups, and measure quantitative indices of RV hemodynamics (RV systolic pressure, pulmonary artery acceleration time and its ratio with RV ejection time, tricuspid annular plane systolic excursion, and RV output), for intergroup comparisons. RESULTS: We evaluated TNEs from 186 neonates with median gestational age of 28.5 weeks (IQR, 25.9-35.9 weeks). Four distinct PAFP patterns were identified (A) near-isosceles triangle (22%), (B) right-angled triangle (29%), (C) notching (40%), and (D) low peak velocity (<0.4 m/s; 9%). Groups A-C demonstrated a stepwise worsening in all indices of PH, whereas pattern D was associated with lower tricuspid annular plane systolic excursion and RV output. Using common definitions of pulmonary hypertension (PH), pattern A performed best to rule out PH (sensitivity range, 81%-90%) and pattern C for diagnosing PH (specificity range, 63%-78%). CONCLUSIONS: Inspection of PAFP is a simple bedside echocardiography measure that provides clinically meaningful information on underlying RV hemodynamics and may aid in screening and monitoring of patients for PH in intensive care units.

The prognostic impact of right ventricular-pulmonary arterial coupling in heart failure: a systematic review and meta-analysis.

The echocardiographic tricuspid annular plane systolic excursion/pulmonary artery systolic pressure (TAPSE/PASP) ratio is a non-invasive surrogate of right ventricular-pulmonary arterial (RV-PA) coupling which corresponds well with the respective invasively derived index. Recently, a wealth of observational data has arisen, outlining its prognostic value in heart failure (HF) patients. To systematically appraise and quantitatively synthesize the evidence of the prognostic value of TAPSE/PASP ratio in left-sided HF regardless of etiology or left ventricular ejection fraction. A systematic literature review was conducted in electronic databases to identify studies reporting the association of TAPSE/PASP ratio with outcomes in patients with HF and, when appropriate, a random-effects meta-analysis was conducted to quantify the unadjusted and adjusted hazard ratios [(a)HRs] for all-cause death and the composite outcome of all-cause death or HF hospitalization. Eighteen studies were deemed eligible encompassing 8,699 HF patients. The applied cut-off value for RV-PA uncoupling varied substantially from 0.27 to 0.58 mm/mmHg, and in most studies values lower than the applied cutoff conveyed dismal prognosis. Eleven studies reported appropriate data for meta-analysis. TAPSE/PASP reduction by 1 mm/mmHg was independently associated with all-cause death (pooled aHR=1.32 [1.06-1.65]; p=0.01; I2=56%) and the composite outcome (pooled aHR=3.48 [1.67-7.25]; p<0.001; I2=0%). When a TAPSE/PASP cutoff value of 0.36 mm/mmHg was applied it yielded independent association with all-cause death (pooled aHR=2.84 [2.22-3.64]; p<0.001; I2=82%). RV-PA coupling assessed by echocardiographic TAPSE/PASP ratio appears to be an independent outcome predictor for HF patients.

Effects of right ventricular remodeling in chronic thromboembolic pulmonary hypertension on the outcomes of balloon pulmonary angioplasty: a 2D-speckle tracking echocardiography study.

BACKGROUND: Balloon pulmonary angioplasty (BPA) improves the prognosis of chronic thromboembolic pulmonary hypertension (CTEPH). Right ventricle (RV) is an important predictor of prognosis in CTEPH patients. 2D-speckle tracking echocardiography (2D-STE) can evaluate RV function. This study aimed to evaluate the effectiveness of BPA in CTEPH patients and to assess the value of 2D-STE in predicting outcomes of BPA. METHODS: A total of 76 patients with CTEPH underwent 354 BPA sessions from January 2017 to October 2022. Responders were defined as those with mean pulmonary artery pressure (mPAP) ≤ 30 mmHg or those showing ≥ 30% decrease in pulmonary vascular resistance (PVR) after the last BPA session, compared to baseline. Logistic regression analysis was performed to identify predictors of BPA efficacy. RESULTS: BPA resulted in a significant decrease in mPAP (from 50.8 ± 10.4 mmHg to 35.5 ± 11.9 mmHg, p < 0.001), PVR (from 888.7 ± 363.5 dyn·s·cm-5 to 545.5 ± 383.8 dyn·s·cm-5, p < 0.001), and eccentricity index (from 1.3 to 1.1, p < 0.001), and a significant increase in RV free wall longitudinal strain (RVFWLS: from 15.7% to 21.0%, p < 0.001). Significant improvement was also observed in the 6-min walking distance (from 385.5 m to 454.5 m, p < 0.001). After adjusting for confounders, multivariate analysis showed that RVFWLS was the only independent predictor of BPA efficacy. The optimal RVFWLS cutoff value for predicting BPA responders was 12%. CONCLUSIONS: BPA was found to reduce pulmonary artery pressure, reverse RV remodeling, and improve exercise capacity. RVFWLS obtained by 2D-STE was an independent predictor of BPA outcomes. Our study may provide a meaningful reference for interventional therapy of CTEPH.

Feasibility, Repeatability, and Correlation to Lung Function of Phase-Resolved Functional Lung (PREFUL) MRI-derived Pulmonary Artery Pulse Wave Velocity Measurements.

BACKGROUND: Pulse wave velocity (PWV) in the pulmonary arteries (PA) is a marker of vascular stiffening. Currently, only phase-contrast (PC) MRI-based options exist to measure PA-PWV. PURPOSE: To test feasibility, repeatability, and correlation to clinical data of Phase-Resolved Functional Lung (PREFUL) MRI-based calculation of PA-PWV. STUDY TYPE: Retrospective. SUBJECTS: 79 (26 female) healthy subjects (age range 19-78), 58 (24 female) patients with chronic obstructive pulmonary disease (COPD, age range 40-77), 60 (33 female) patients with suspected pulmonary hypertension (PH, age range 28-85). SEQUENCE: 2D spoiled gradient echo, 1.5T. ASSESSMENT: PA-PWV was measured from PREFUL-derived cardiac cycles based on the determination of temporal and spatial distance between lung vasculature voxels using a simplified (sPWV) method and a more comprehensive (cPWV) method including more elaborate distance calculation. For 135 individuals, PC MRI-based PWV (PWV-QA) was measured. STATISTICAL TESTS: Intraclass-correlation-coefficient (ICC) and coefficient of variation (CoV) were used to test repeatability. Nonparametric tests were used to compare cohorts. Correlation of sPWV/cPWV, PWV-QA, forced expiratory volume in 1 sec (FEV1) %predicted, residual volume (RV) %predicted, age, and right heart catheterization (RHC) data were tested. Significance level α = 0.05 was used. RESULTS: sPWV and cPWV showed no significant differences between repeated measurements (P-range 0.10-0.92). CoV was generally lower than 15%. COPD and PH patients had significantly higher sPWV and cPWV than healthy subjects. Significant correlation was found between sPWV or cPWV and FEV1%pred. (R = -0.36 and R = -0.44), but not with RHC (P-range -0.11 - 0.91) or age (P-range 0.23-0.89). Correlation to RV%pred. was significant for cPWV (R = 0.42) but not for sPWV (R = 0.34, P = 0.055). For all cohorts, sPWV and cPWV were significantly correlated with PWV-QA (R = -0.41 and R = 0.48). DATA CONCLUSION: PREFUL-derived PWV is feasible and repeatable. PWV is increased in COPD and PH patients and correlates to airway obstruction and hyperinflation. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 2.

Novel application of the Diabolo technique to restrict pulmonary blood flow in a single ventricle patient with a right ventricle to pulmonary artery conduit.

Balancing pulmonary and systemic circulations in single ventricle patients with a conduit after Stage 1 palliation is challenging. A transcatheter intervention for excessive pulmonary blood flow would provide benefit. We report a case of a critically ill single ventricle patient with symptoms of excessive pulmonary blood flow after Stage 1 despite maximal medical therapy. The patient underwent percutaneous intraluminal downsizing of the right ventricle to pulmonary artery conduit using a novel application of the Diabolo-covered stent technique, with subsequent clinical improvement. A second catheterization was performed during the interstage period with successful dilation of the stent to achieve appropriate saturations. The Diabolo technique can be successfully employed in this population to restrict pulmonary blood flow and has the advantage of being adjusted during placement and in subsequent interventions.

Bilateral Harmony™ valve placement in branch pulmonary arteries.

While newer self-expanding pulmonic valves were primarily designed for larger right ventricular outflow tracks, there are instances where even larger anatomies cannot accommodate these devices. In this report, we describe the successful implantation of two Harmony™ valves in bilateral branch pulmonary arteries after exhausting other options.

Ventriculo-arterial uncoupling with an impella assisted HVAD: The p-D LVAD.

This paper presents the novel use of a temporary percutaneous ventricular assist device (pVAD) in a 51-year-old man with an implanted durable left ventricular assist device (d-LVAD). The pre-existing left ventricular assist device was unable to successfully unload the left ventricle, and the addition of the temporary pVAD achieved successful unloading as well as a decrease in pulmonary artery pressures without compromising the function of the right ventricle allowing safe UNOS listing for orthotopic heart transplantation.

Prognostic impact of main pulmonary artery to ascending aorta diameter ratio in patients with severe aortic stenosis underwent transcatheter aortic valve implantation.

BACKGROUND: Pulmonary hypertension (PH) and right ventricular dysfunction are poor prognostic predictors in patients underwent transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS). AIMS: The prognostic impact of the main pulmonary artery/ascending aorta diameter ratio (MPA/AOr), measured simply by computed-tomographic angiography (CTA), was investigated in this patient group. METHODS: A total of 374 retrospectively evaluated patients (mean age 78.1 ± 8.4 years, 192 [51.3%] females) who underwent TAVI for severe AS were included. MPA/AOr was measured on preprocedural CTA in all patients and the effect of this measurement on the presence of PH, in-hospital and 2-year-overall long-term mortality was investigated. RESULTS: The presence of PH was defined as a systolic pulmonary artery pressure (sPAP) >42 mmHg measured by echocardiography. According to multivariate-logistic-regression analysis, MPA/AOr (adjusted [Adj] odds ratio [OR]: 1.188, confidence interval [CI] 95% [1.002-1.410], p = 0.048), tricuspid annular plane systolic excursion (TAPSE) (adj OR:0.736, CI 95% [0.663-0.816], p < 0.001) and left atrial diameter (adj OR:1.051, CI 95% [1.007-1.098], p = 0.024) were identified as independent predictors of PH. In addition, a statistically significant correlation was found between MPA/AOr and TAPSE (r: -0.283, p < 0.001). Furthermore, MPA/AOr was found to be an independent predictor of both in-hospital (adj OR:1.434, CI 95% [1.093-1.881], p = 0.009) and 2-year long-term (adj OR:1.518, CI 95% [1.243-1.853], p < 0.001) mortality in multivariate analysis including TAPSE, STS score and sPAP. In the 2-year Kaplan-Meier survival probability analysis, an MPA/AOr >0.86 was found to have a hazard ratio of 3.697 (95% CI: 2.341-5.840), with a log-rank p < 0.001. CONCLUSION: MPA/AOr, which can be measured simply by CTA, may be useful as an indicator of the presence of PH and poor prognosis in patients planned for TAVI for severe AS.

Results of the multicenter early feasibility study (EFS) of the Renata Minima stent as treatment for branch pulmonary artery stenosis and coarctation of aorta in infants.

BACKGROUND: Stent implantation has become standard of care in older children and adults for treatment of branch pulmonary artery stenosis (BPAS) and coarctation aorta (CoAo). There are no stents approved or available for infants that have the potential to be dilated to adult diameters. The Minima stent was designed to fulfill this unmet need. METHODS: Multicenter, prospective, nonrandomized early feasibility study evaluating safety and effectiveness of the Minima stent for treatment of BPAS and CoAo. Primary endpoints included: (1) successful deployment across lesion, (2) stenosis relief defined by an increase in angiographic diameter of >50% and (3) freedom from stent explant, embolization or migration at 30 days and 6 months. RESULTS: Between 2/2022 and 5/2022, 10 pts underwent Minima stent implantation with a median age and weight of 9 months (4-43 months) and 7.6 kg (5.1-16.9 kg). Procedural success and predefined stenosis relief was achieved in all cases (CoAo [n = 4], BPAS [n = 6]). Adverse events occurred in 3 pts: transient diminished lower extremity pulse (n = 2), distal stent on-balloon displacement successfully managed in the catheterization suite (n = 1). There were no deaths or major adverse events. All patients were free from stent explant and migration at 30 days and 6 months with no evidence for significant restenosis at latest follow-up. CONCLUSIONS: Implantation of the Renata Minima stent was safe and effective for the treatment of BPAS and CoAo in this small cohort of infants and young children during early follow-up. Based on these early results, an expanded study with longer follow-up is warranted.

The adaptability of the Pulsta valve to the diverse main pulmonary artery shape of native right ventricular outflow tract disease.

BACKGROUND: Pulsta valve is increasingly used for percutaneous pulmonary valve implantation (PPVI) in patients with a large native right ventricular outflow tract (RVOT). This study aims to elucidate the outcomes of Pulsta valve implantation within the native RVOT and assess its adaptability to various native main pulmonary artery (PA) anatomies. METHODS: A multicenter retrospective study included 182 patients with moderate to severe pulmonary regurgitation in the native RVOT who underwent PPVI with Pulsta valves® between February 2016 and August 2023 at five Korean and Taiwanese tertiary referral centers. RESULTS: Pulsta valve implantation was successful in 179 out of 182 patients (98.4%) with an average age of 26.7 ± 11.0 years. The median follow-up duration was 29 months. Baseline assessments revealed enlarged right ventricle (RV) volume (mean indexed RV end-diastolic volume: 163.1 (interquartile range, IQR: 152.0-180.3 mL/m²), which significantly decreased to 123.6(IQR: 106.6-137.5 mL/m2  after 1 year. The main PA types were classified as pyramidal (3.8%), straight (38.5%), reverse pyramidal (13.2%), convex (26.4%), and concave (18.1%) shapes. Pulsta valve placement was adapted, with distal main PA for pyramidal shapes and proximal or mid-PA for reverse pyramidal shapes. Two patients experienced Pulsta valve embolization to RV, requiring surgical removal, and one patient encountered valve migration to the distal main PA, necessitating surgical fixation. CONCLUSIONS: Customized valve insertion sites are pivotal in self-expandable PPVI considering diverse native RVOT shape. The rather soft and compact structure of the Pulsta valve has characteristics to are adaptable to diverse native RVOT geometries.

Rationale and design of the randomized COmparison of Methods for Pulmonary blood flow Augmentation: Shunt versus Stent (COMPASS) trial: A Pediatric Heart Network study.

Neonates with congenital heart disease (CHD) and ductal-dependent pulmonary blood flow (DD-PBF) require early intervention. Historically, this intervention was most often a surgical systemic-to-pulmonary shunt (SPS; e.g., Blalock-Thomas-Taussig shunt). However, over the past two decades an alternative to SPS has emerged in the form of transcatheter ductal artery stenting (DAS). While many reports have indicated safety and durability of the DAS approach, few studies compare outcomes between DAS and SPS. The reports that do exist are comprised primarily of small-cohort single-center reviews. Two multicenter retrospective studies suggest that DAS is associated with similar or superior survival compared to SPS. These studies offer the best evidence to-date, and yet both have important limitations. The authors describe herein the rationale and design of the COMPASS (COmparison of Methods for Pulmonary blood flow Augmentation: Shunt vs. Stent) Trial (NCT05268094, IDE G210212). The COMPASS Trial aims to randomize 236 neonates with DD-PBF to either DAS or SPS across approximately 27 pediatric centers in North America. The goal of this trial is to compare important clinical outcomes between DAS and SPS over the first year of life in a cohort of neonates balanced by randomization to assess whether one method of palliation demonstrates therapeutic superiority.

Extravascular protrusion of the Alterra adaptive prestent identified on surveillance computed tomography imaging.

BACKGROUND: The Alterra adaptive prestent is a novel self-expanding device designed to provide a landing zone for the 29 mm SAPIEN 3 valve to treat pulmonary regurgitation in patients with a right ventricular outflow tract that is too large for a balloon expandable valve alone. The mechanism of fixation for the Alterra prestent is radial force from the self-expanding stent frame, combined with a unique set of flared "tines" that protrude from both ends of the stent. AIMS, METHODS, AND RESULTS: In this report, we describe 6 patients who underwent uncomplicated transcatheter pulmonary valve replacement with an Alterra adaptive prestent and SAPIEN 3 valve and had surveillance chest computed tomography (CT) scans performed 1 day to 21 months after implant. In each patient, the CT scan demonstrated extravascular extension of a portion of the Alterra prestent, without clinical sequelae, but with extension into the ascending aorta in 1 patient and contact with the ascending aorta, left pulmonary vein, or left atrial appendage in 3 others. CONCLUSIONS: Surveillance CT imaging shows that the Alterra prestent can perforate the pulmonary artery and/or right ventricle. Although no sequelae were seen in these patients, prestent perforation has the potential to be clinically important. Implanters should be aware of this finding and its potential implications. As experience with the Alterra prestent grows, it will be important to further define the risk factors, incidence, and implications of this phenomenon.

Percutaneous pulmonary aspiration thrombectomy in an adolescent fontan patient using a large-bore system.

We describe the safe and effective percutaneous pulmonary thrombectomy in an 18-year-old female with a Fontan circulation using the FlowTriever® device (Inari Medical®, Irvine, US). Aspiration thrombectomy of both pulmonary arteries was performed using 24 and 16 F FlowTriever® catheters retrieving large amounts of thrombus material resulting in near total angiographic recanalization.

Transcatheter Fontan completion: Creation of an extracardiac Fontan.

Patients with functionally univentricular hearts are usually palliated surgically. There have been several reports of successful attempts to complete the Fontan procedure without surgery. The pathways created at the time of the preconditioning were largely reminiscent of the lateral tunnel Fontan. However, this approach is still confidentially limited to a small number of centers. In 2013, we designed a circuit that mimics the actual surgical technique of extracardiac total cavopulmonary connection to allow for transcatheter completion in an animal study. A polytetrafluoroethylene conduit was connected between the pulmonary artery and the inferior vena cava (IVC). The superior anastomosis was occluded to avoid flow between IVC and superior vena cava (SVC). The conduit was connected to the right atrium (RA) and a large fenestration was created to allow free flow from the IVC to the RA. Extrapolating our approach, a center reported the successful transcatheter completion of an extracardiac Fontan in a 6-year-old child. However, this technique is not directly transposable to our population of patients who require preconditioning in infancy. We report here an innovative extension of this technique that may allow preparing patients in infancy, ideally at the time of the Glenn in the future, to receive an extracardiac Fontan at 2 years/11 kg without additional surgery.

The impact of unilateral pulmonary artery stenosis on right ventricular to pulmonary arterial coupling in patients with transposition of the great arteries.

BACKGROUND: Unilateral pulmonary artery (PA) stenosis is common in the transposition of the great arteries (TGA) after arterial switch operation (ASO) but the effects on the right ventricle (RV) remain unclear. AIMS: To assess the effects of unilateral PA stenosis on RV afterload and function in pediatric patients with TGA-ASO. METHODS: In this retrospective study, eight TGA patients with unilateral PA stenosis underwent heart catheterization and cardiac magnetic resonance (CMR) imaging. RV pressures, RV afterload (arterial elastance [Ea]), PA compliance, RV contractility (end-systolic elastance [Ees]), RV-to-PA (RV-PA) coupling (Ees/Ea), and RV diastolic stiffness (end-diastolic elastance [Eed]) were analyzed and compared to normal values from the literature. RESULTS: In all TGA patients (mean age 12 ± 3 years), RV afterload (Ea) and RV pressures were increased whereas PA compliance was reduced. RV contractility (Ees) was decreased resulting in RV-PA uncoupling. RV diastolic stiffness (Eed) was increased. CMR-derived RV volumes, mass, and ejection fraction were preserved. CONCLUSION: Unilateral PA stenosis results in an increased RV afterload in TGA patients after ASO. RV remodeling and function remain within normal limits when analyzed by CMR but RV pressure-volume loop analysis shows impaired RV diastolic stiffness and RV contractility leading to RV-PA uncoupling.