Pulmonary Hypertension Induced by Right Pulmonary Artery Occlusion: Hemodynamic Consequences of Bmpr2 Mutation.

BACKGROUND: The primary genetic risk factor for heritable pulmonary arterial hypertension is the presence of monoallelic mutations in the BMPR2 gene. The incomplete penetrance of BMPR2 mutations implies that additional triggers are necessary for pulmonary arterial hypertension occurrence. Pulmonary artery stenosis directly raises pulmonary artery pressure, and the redirection of blood flow to unobstructed arteries leads to endothelial dysfunction and vascular remodeling. We hypothesized that right pulmonary artery occlusion (RPAO) triggers pulmonary hypertension (PH) in rats with Bmpr2 mutations. METHODS AND RESULTS: Male and female rats with a 71 bp monoallelic deletion in exon 1 of Bmpr2 and their wild-type siblings underwent acute and chronic RPAO. They were subjected to full high-fidelity hemodynamic characterization. We also examined how chronic RPAO can mimic the pulmonary gene expression pattern associated with installed PH in unobstructed territories. RPAO induced precapillary PH in male and female rats, both acutely and chronically. Bmpr2 mutant and male rats manifested more severe PH compared with their counterparts. Although wild-type rats adapted to RPAO, Bmpr2 mutant rats experienced heightened mortality. RPAO induced a decline in cardiac contractility index, particularly pronounced in male Bmpr2 rats. Chronic RPAO resulted in elevated pulmonary IL-6 (interleukin-6) expression and decreased Gdf2 expression (corrected P value<0.05 and log2 fold change>1). In this context, male rats expressed higher pulmonary levels of endothelin-1 and IL-6 than females. CONCLUSIONS: Our novel 2-hit rat model presents a promising avenue to explore the adaptation of the right ventricle and pulmonary vasculature to PH, shedding light on pertinent sex- and gene-related effects.

Three-Decade Experience With Management of Coronary Artery Fistulas in Children.

BACKGROUND: The treatment approach for coronary artery fistulas (CAFs) is debatable, and long-term outcomes are unknown. METHODS: This was a retrospective institutional data review of children in whom echocardiographically suspected CAFs were confirmed during cardiac catheterisation from 1997 to 2023. Treatment approach and outcomes were assessed. RESULTS: We identified 94 CAFs in 78 patients (42.3% male), median age 3.4 years (interquartile range [IQR] 0.9-6.6 y). Twenty-five patients (32%) had other congenital anomalies; 41 (78.8%) of the 52 patients with isolated CAFs were asymptomatic. The most common site of CAF origin and drainage was the left system (62.8%) and right cardiac cavities (80.8%). Overall median follow-up was 101 months (iqr 41-185 mo); 23 patients (29.5%) with 35 (37.2%) small or nonshunting CAFs had conservative management, and 20 (87%) of those 23 patients had an uneventful follow-up; 8 patients (10.2%) with 9 (9.6%) complex CAFs were directly sent for surgery; 1 patient had early surgical patch failure needing surgical reintervention; 47 patients (60.3%) had catheter closure of 50 (53.2%) medium- or large-sized CAFs with the use of coils (30%), vascular plugs (20%), nitinol duct occluders (40%), or material combination (10%). Six serious complications occurred. Two-thirds of patients with unsuccessful catheter procedures had subsequent surgeries. Two-thirds of patients with mild shunts had successful redo closures. One asymptomatic patient had recanalisation after 12 years and is under watchful observation. CONCLUSIONS: CAFs have various anatomies and clinical presentations. Transcatheter closure is effective in carefully selected patients but is not complication free. Surgery is a valuable up-front option in complex CAFs or bailout of unsuccessful transcatheter closures, although it is not frequently used.

Postoperative catheter thrombaspiration to open an occluded right ventricle-to-pulmonary artery conduit in child.

We report on a 6-year-old girl (18 kg/120 cm) who was diagnosed on day 6 postoperative with an occlusive thrombosis of a right ventricle-to-pulmonary artery conduit in the setting of a Ross procedure that was performed for severe native aortic valve insufficiency secondary to late diagnosis of bacterial endocarditis. We applied the Indigo® aspiration system from Penumbra® (Alameda, USA) to mechanically dissolve and remove the thrombus, restore flow, gradually wean from extracorporeal support, and replace the conduit after 4 days. The patient experiences good surgical outcomes at 3 months of follow-up.

Renal function after ductus arteriosus transcatheter closure with or without angiography in very preterm infants.

AIM: Transcatheter closure of the patent ductus arteriosus (TCPDA) is increasingly used in preterm infants as an alternative to surgical ligation. However, clinically ill preterm infants are at risk of contrast nephropathy due to the angiography contrast agents used during the procedure. METHODS: We performed a single-centre before-and-after comparative study in VLBW infants to compare the kinetics of serum creatinine during the first 4 days after TCPDA with or without angiography. RESULTS: 69 patients were included and divided into two groups: TCPDA with (contrast+; n = 37) and without (contrast-, n = 32) use of contrast agent. The median dose [range] of contrast agent was 1.0 mL/kg [0.6-2.4 mL/kg]. The change in serum creatinine level between day 2 to 4 after TCPCA and baseline decreased in the contrast- group (-17% [-46%; 18%]), while it increased in the contrast+ group (7% [-24%; 202%] p = 0.002). Comparison of blood urea levels between groups showed similar significant differences. The change in serum creatinine between day 2 to 4 and baseline was significantly correlated with the dose of contrast agent (r2 = 0.682; p < 0.001). CONCLUSION: The use of contrast agents during TCPDA can potentially harm the renal function of very preterm infants. Therefore, we advise minimising or avoiding the use of contrast agents.

Outcomes of transcatheter pulmonary SAPIEN 3 valve implantation: an international registry.

BACKGROUND AND AIMS: Transcatheter pulmonary valve implantation (TPVI) is indicated to treat right-ventricular outflow tract (RVOT) dysfunction related to congenital heart disease (CHD). Outcomes of TPVI with the SAPIEN 3 valve that are insufficiently documented were investigated in the EUROPULMS3 registry of SAPIEN 3-TPVI. METHODS: Patient-related, procedural, and follow-up outcome data were retrospectively assessed in this observational cohort from 35 centres in 15 countries. RESULTS: Data for 840 consecutive patients treated in 2014-2021 at a median age of 29.2 (19.0-41.6) years were obtained. The most common diagnosis was conotruncal defect (70.5%), with a native or patched RVOT in 50.7% of all patients. Valve sizes were 20, 23, 26, and 29 mm in 0.4%, 25.5%, 32.1%, and 42.0% of patients, respectively. Valve implantation was successful in 98.5% [95% confidence interval (CI), 97.4%-99.2%] of patients. Median follow-up was 20.3 (7.1-38.4) months. Eight patients experienced infective endocarditis; 11 required pulmonary valve replacement, with a lower incidence for larger valves (P = .009), and four experienced pulmonary valve thrombosis, including one who died and three who recovered with anticoagulation. Cumulative incidences (95%CI) 1, 3, and 6 years after TPVI were as follows: infective endocarditis, 0.5% (0.0%-1.0%), 0.9% (0.2%-1.6%), and 3.8% (0.0%-8.4%); pulmonary valve replacement, 0.4% (0.0%-0.8%), 1.3% (0.2%-2.4%), and 8.0% (1.2%-14.8%); and pulmonary valve thrombosis, 0.4% (0.0%-0.9%), 0.7% (0.0%-1.3%), and 0.7% (0.0%-1.3%), respectively. CONCLUSIONS: Outcomes of SAPIEN 3 TPVI were favourable in patients with CHD, half of whom had native or patched RVOTs.

Cerebral embolic protection during transcatheter stent expansion of restrictive extra-cardiac Fontan conduit.

We report a 20-year-old female patient (76 Kg/164 cm) with an extra-cardiac Fontan circulation who was referred to our institution for exertional dyspnoea and desaturation. The patient was diagnosed with a large calcified thrombus at the level of the Fontan fenestration, protruding inside the lumen of the conduit and reducing the diameter by half with a 3 mmHg pressure gradient. Transcatheter stent expansion of the obstructed extra-cardiac conduit was done with a 48 mm long XXL PTFE-covered Optimus-CVS® under temporary cerebral embolic protection with a TriGUARD-3™ deflection filter device (Keystone Heart). There was no procedural complication and the 3 months clinical outcomes are good.

Outcomes of coronary artery obstructions after the arterial switch operation for transposition of the great arteries.

OBJECTIVE: Coronary obstruction is a rare but common complication of the arterial switch operation for transposition of the great arteries. The majority of patients remain asymptomatic and no risk factors allow targeting for reinforced surveillance. We aim to review the natural history of patients diagnosed with coronary obstruction after arterial switch operation for transposition of the great arteries and occurrence of coronary-related outcomes. METHODS: We retrospectively reviewed medical records of the 102 patients diagnosed with coronary obstruction after arterial switch operation for transposition of the great arteries in our institution from 1981 to 2022. Outcomes were anti-ischemic treatment introduction, revascularization (surgical or percutaneous angioplasty), and death; investigations that motivated revascularization were also reviewed. RESULTS: Twenty-eight out of 102 patients presented with myocardial ischemia during the immediate postoperative phase, 31 were diagnosed when symptomatic, and 43 were identified at the presymptomatic stage, according to our screening policy in preschool-aged children. Stenosis-related event occurrence was, respectively, 29 out of 31 and 32 out of 43 in the latter 2 subgroups. Coronary-related mortality reached 10% in patients diagnosed when symptomatic; no patients died in the presymptomatic subgroup. Of the 28 low-risk patients with no signs of ischemia at diagnosis, 10 developed obstruction warranting reintervention during follow-up. Revascularization was motivated by appearance of symptoms in patients with severe stenosis in normal coronary dispositions, and by clinical symptoms or documented silent ischemia in abnormal coronary patterns. CONCLUSIONS: Occurrence of stenosis-related events remains significant in patients after arterial switch operation, underlining the importance of early diagnosis for timely intervention. Initial anatomical evaluation identifies stenotic and at-risk patients; this will require periodical function testing. Follow-up modalities can be tailored to a patient's individual anatomic characteristics.

Transcatheter Closure of Superior Sinus Venosus Defects.

Superior sinus venosus defect is a communication between the right and left atrium located above the upper margin of the oval fossa, immediately inferior to the junction of the superior vena cava and the right atrium. It is systematically associated with partial anomalous pulmonary venous drainage, especially of the right upper pulmonary vein. Surgical repair has been the gold standard approach to close that defect. Introduced in 2014, percutaneous closure has gradually become a safe and effective alternative to surgery in carefully selected patients, although worldwide experience remains limited. This article provides an appraisal of the patients' selection process and a step-by-step description of the procedure as well as a comprehensive review of its outcomes.

Transcatheter Management of Pulmonary Sequestrations in Children-A Single-Center Experience.

BACKGROUND: A pulmonary sequestration (PS) is an area of bronchopulmonary tissue with aberrant arterial supply. Transcatheter occlusion of PSs is an appealing treatment option, but data on outcomes remain scarce. We aim to describe our experience with transcatheter management of PS in infants and children. METHODS: Retrospective review of clinical data of all patients with suspected PS sent for diagnostic and/or interventional cardiac catheterization at our institution between January 1999 and May 2021. Procedural considerations, techniques, standard safety, and outcomes were assessed. RESULTS: We identified 71 patients (52.1% males), with median age and weight of 4.9 months (IQR, 2.1-26.6) and 4.2 kg (IQR, 3.9-12.1), respectively. Sixty-one (86%) patients had associated congenital heart defects (CHDs). Forty-two (59%) patients had pulmonary arterial hypertension (PAH) at the time of diagnosis. Fifty-three (74.7%) patients underwent embolization of the PS feeding vessel using microcoils and/or vascular plugs, and eight (15.1%) of these were neonates who presented with severe PAH and cardiac failure. Two patients had large feeding vessels and were treated surgically. Sixteen (22.5%) patients with small feeding vessels received conservative management. At median follow-up of 36.4 months (IQR, 2.1-89.9), seven patients had died, 24 patients had CHD corrective surgeries, 26 patients had redo catheterizations, and five patients had persistent PAH. No PS surgical resection was needed, and no infection of the remaining lung tissue occurred. CONCLUSIONS: Transcatheter assessment and treatment of PSs is a safe and effective procedure. Neonates with large PSs are severely symptomatic and improve remarkably after PS closure. PS embolization and surgical repair of associated CHDs generally leads to the normalization of pulmonary pressures.

Congenital disconnection of the pulmonary arteries.

OBJECTIVES: Disconnected pulmonary artery (PA) is a rare anomaly that can be isolated or associated with complex intracardiac malformations. Early reimplantation of the disconnected PA is recommended to allow growth and satisfactory pulmonary perfusion while preventing collateral artery development. The aim of this study was to describe the characteristics of patients with disconnected PA and, for those who had surgical reimplantation, to determine the incidence, delay and predictive factors of reintervention for reconnected PA stenosis. METHODS: We include patients with the diagnosis of congenitally disconnected PA and surgical repair at our institution. RESULTS: Retrospective observational study of 55 patients with a disconnected PA. Fifty-one underwent surgical correction and were followed up at our institution between 2000 and 2022. Disconnected PAs were observed in isolation in 31% of the cases. The most frequent form was left PA originating from the arterial duct (58%). The reimplantation was done at the median age of 12 days. Anastomotic stenosis was observed during follow-up in 71% of the patients with 75% of them requiring reintervention (55% of the population). The median delay to reintervention was 3.2 years after reimplantation, and >25% of reinterventions on the reimplanted PA occurred within the first postoperative year. We found more reintervention if associated cardiac defect, without significant statistic difference. Weight at re-confluence, presence of ductal tissue at the origin of the PA and prior shunt placement on the disconnected PA were not found to be risk factors for reintervention. DISCUSSION: After surgical reimplantation of PA, >50% of patients required reintervention for PA stenosis. Technical improvements should be sought to reduce the incidence of this complication.

Lympho-hematopoietic malignancies risk after exposure to low dose ionizing radiation during cardiac catheterization in childhood.

Pediatric patients with congenital heart disease (CHD) often undergo low dose ionizing radiation (LDIR) from cardiac catheterization (CC) for the diagnosis and/or treatment of their disease. Although radiation doses from a single CC are usually low, less is known about the long-term radiation associated cancer risks. We aimed to assess the risk of lympho-hematopoietic malignancies in pediatric CHD patients diagnosed or treated with CC. A French cohort of 17,104 children free of cancer who had undergone a first CC from 01/01/2000 to 31/12/2013, before the age of 16 was set up. The follow-up started at the date of the first recorded CC until the exit date, i.e., the date of death, the date of first cancer diagnosis, the date of the 18th birthday, or the 31/12/2015, whichever occurred first. Poisson regression was used to estimate the LDIR associated cancer risk. The median follow-up was 5.9 years, with 110,335 person-years. There were 22,227 CC procedures, yielding an individual active bone marrow (ABM) mean cumulative dose of 3.0 milligray (mGy). Thirty-eight incident lympho-hematopoietic malignancies were observed. When adjusting for attained age, gender and predisposing factors to cancer status, no increased risk was observed for lympho-hematopoietic malignancies RR/mGy = 1.00 (95% CI: 0.88; 1.10). In summary, the risk of lympho-hematopoietic malignancies and lymphoma was not associated to LDIR in pediatric patients with CHD who undergo CC. Further epidemiological studies with greater statistical power are needed to improve the assessment of the dose-risk relationship.

Systematic Electrophysiological Study Prior to Pulmonary Valve Replacement in Tetralogy of Fallot: A Prospective Multicenter Study.

BACKGROUND: Ventricular arrhythmias and sudden death are recognized complications in tetralogy of Fallot. Electrophysiological studies (EPS) before pulmonary valve replacement (PVR), the most common reintervention in tetralogy of Fallot, could potentially inform therapy to improve arrhythmic outcomes. METHODS: A prospective multicenter study was conducted to systematically assess EPS with programmed ventricular stimulation in patients with tetralogy of Fallot referred for PVR from January 2020 to December 2021. A standardized stimulation protocol was used across all centers. RESULTS: A total of 120 patients were enrolled, mean age 39.2±14.5 years, 53.3% males. Sustained ventricular tachycardia was induced in 27 (22.5%) patients. When identifiable, the critical isthmus most commonly implicated (ie, in 90.0%) was between the ventricular septal defect patch and pulmonary annulus. Factors independently associated with inducible ventricular tachycardia were history of atrial arrhythmia (odds ratio, 8.56 [95% CI, 2.43-34.73]) and pulmonary annulus diameter >26 mm (odds ratio, 5.05 [95% CI, 1.47-21.69]). The EPS led to a substantial change in management in 23 (19.2%) cases: 18 (15.0%) had catheter ablation, 3 (2.5%) surgical cryoablation during PVR, and 9 (7.5%) defibrillator implantation. Repeat EPS 5.1 (4.8-6.2) months after PVR was negative in 8 of 9 (88.9%) patients. No patient experienced a sustained ventricular arrhythmia during 13 (6.1-20.1) months of follow-up. CONCLUSIONS: Systematically performing programmed ventricular stimulation in patients with tetralogy of Fallot referred for PVR yields a high rate of inducible ventricular tachycardia and carries the potential to alter management. It remains to be determined whether a standardized treatment approach based on the results of EPS will translate into improved outcomes. REGISTRATION: URL: https://clinicaltrials.gov/ct2/show/NCT04205461; Unique identifier: NCT04205461.

Failure to post-dilate BeSmooth peripheral stents to adult vessel size diameters during benchside tests.

BACKGROUND: Low-profile stent implantation remains a rescue treatment for aortic coarctation and branch pulmonary arteries stenosis in small children. Stent re-expansion to cope with vascular growth remains problematic. OBJECTIVES: To evaluate ex vivo feasibility and mechanical behaviour of over-dilating BeSmooth peripheral stents (Bentley InnoMed, Germany). METHODS: Three BeSmooth peripheral stents in diameters of 7, 8, and 10 mm were dilated to nominal pressure and then 13 atm. BeSmooth Ø7 × 23 mm was sequentially post-dilated using 12, 14, and 16 mm high-pressure balloons. BeSmooth Ø10 × 57 mm was post-dilated with a 14 mm balloon and then with a 48 mm bare-metal Optimus XXL stent hand-mounted on a 14 mm balloon (stent-in-stent). BeSmooth Ø8 × 57 mm was directly post-dilated with a 48 mm bare-metal Optimus XXL stent hand-mounted on a 16 mm balloon (stent-in-stent). The stents' diameter and length were measured. Digital inflation pressure was noted. Balloon rupture and stent fracture patterns were closely evaluated. RESULTS: At 20atm pressure, BeSmooth Ø7 × 23 mm shortened to 2 mm forming a 12 mm diameter solid ring circle and the woven balloon ruptured radially. At 10 atm pressure, BeSmooth Ø10 × 57 mm fractured longitudinally in various dispatched breaking points at a diameter of 13 mm without shortening and ruptured the balloon with multiple pinholes. At 10 atm pressure, BeSmooth Ø8 × 57 mm fractured centrally at three different points at a diameter of 11.5 mm without shortening and the balloon broke radially in half. CONCLUSIONS: In our benchmark tests, extreme shortening, severe balloon rupture, or unpredictable stent fracture patterns at small balloon diameters limits safe post-dilation of BeSmooth stents beyond 13 mm. BeSmooth stents are not ideal candidates for off-label stent interventions in smaller patients.

Transvenous retrograde thoracic duct embolization for effective treatment of recurrent plastic bronchitis after fontan palliation.

We report the case of a 5.5-year-old patient (16 kg/105 cm) who presented with plastic bronchitis (PB) refractory to conservative treatment 3 months after completion of Fontan palliation. Bi-inguinal transnodal fluoroscopy-guided lymphangiogram confirmed the chylous leak originating from the thoracic duct (TD) into the chest and did not opacify any central lymphatic vessel for direct transabdominal puncture. Retrograde transfemoral approach was adopted to catheterize the TD and selectively embolize its caudal portion using microcoils and liquid embolic adhesive. Recurrence of symptoms after 2 months indicated a redo catheterization to occlude the TD entirely using the same technique. The procedure was successful and the patient was discharged after 2 days with sustained clinical improvement at 24 months postoperative. In the context of refractory PB, end-to-end transvenous retrograde embolization of the TD appears to be an interesting alternative to more complex interventions such as transabdominal puncture, decompression, or surgical ligation of the TD.

Discordance between 2D and 4D flow in the assessment of pulmonary regurgitation severity: a right ventricular remodeling follow-up study.

OBJECTIVES: Pulmonary regurgitation (PR) is common in adult congenital heart disease (ACHD). 2D phase contrast MRI is the reference method for the quantification of PR and helps in the decision of pulmonary valve replacement (PVR). 4D flow MRI can be an alternative method to estimate PR but more validation is still needed. Our purpose was to compare 2D and 4D flow in PR quantification using the degree of right ventricular remodeling after PVR as the reference standard. METHODS: In 30 adult patients with a pulmonary valve disease recruited between 2015 and 2018, PR was assessed using both 2D and 4D flow. Based on the clinical standard of care, 22 underwent PVR. The pre PVR estimate of PR was compared using the post-operative decrease in right ventricle end-diastolic volume on follow-up exam as reference. RESULTS: In the overall cohort, regurgitant volume (Rvol) and regurgitant fraction (RF) of PR measured by 2D and 4D flow were well correlated but with moderate agreement in the overall cohort (r = 0.90, mean diff. -14 ± 12.5 mL; and r = 0.72, mean diff. -15 ± 13%; all p < 0.0001). Correlations between Rvol estimates and right ventricle end-diastolic volume decrease after PVR was higher with 4D flow (r = 0.80, p < 0.0001) than with 2D flow (r = 0.72, p < 0.0001). CONCLUSIONS: In ACHD, PR quantification from 4D flow better predicts post-PVR right ventricle remodeling than that from 2D flow. Further studies are needed to evaluate the added value of this 4D flow quantification for guiding replacement decision. KEY POINTS: • Using 4D flow MRI allows a better quantification of pulmonary regurgitation in adult congenital heart disease than 2D flow when taking right ventricle remodeling after pulmonary valve replacement as a reference. • A plane positioned perpendicular to the ejected flow volume as allowed by 4D flow provides better results to estimate pulmonary regurgitation.

Monitoring of Hemodynamics With Right Heart Catheterization in Children With Pulmonary Arterial Hypertension.

Background Right heart catheterization (RHC) is a high-risk procedure in children with pulmonary arterial hypertension without clear guidelines for the indications and targets of invasive reassessment. Our objectives are to define the aims of repeated RHC and evaluate the correlation between noninvasive criteria and hemodynamic parameters. Methods and Results Clinical and hemodynamic characteristics from 71 incident treatment-naïve children (median age 6.2 years) with pulmonary arterial hypertension who had a baseline and reevaluation RHC were analyzed. Correlations between noninvasive predictors and hemodynamic parameters were tested. Adverse outcomes were defined as death, lung transplantation, or Potts shunt. At baseline, pulmonary vascular resistance index (hazard ratio [HR] 1.07 per 1 WU·m2 increase [95% CI, 1.02-1.12], P=0.002), stroke volume index (HR 0.95 per 1 L·min-1·m-2 increase [95% CI, 0.91-0.99], P=0.012), pulmonary artery compliance index (HR 0.16 per 1 mL·mm Hg-1·m-2 increase [95% CI, 0.051-0.52], P=0.002), and right atrial pressure (HR, 1.31 per 1 mm Hg increase [95% CI, 1.01-1.71], P=0.043) were associated with adverse outcomes. Pulmonary vascular resistance index, pulmonary artery compliance index, and right atrial pressure were still associated with a worse outcome at second RHC. Noninvasive criteria accurately predicted hemodynamic evolution; however, 70% of the patients who had improved based on noninvasive criteria still presented at least 1 "at risk" hemodynamics at second RHC. Conclusions Pulmonary vascular resistance index, pulmonary artery compliance index, and right atrial pressure are solid predictors of adverse outcomes in pediatric pulmonary arterial hypertension and potential therapeutic targets. Noninvasive criteria accurately predict the evolution of hemodynamic parameters, but insufficiently. Repeated RHC are helpful to identify children with persistent higher risk after treatment introduction.

Early spontaneous closure of large arterial ducts in two term neonates with Ebstein anomaly after failed attempts of transcatheter closure.

In neonatal Ebstein's anomaly of the tricuspid valve, prolonged ductal patency in patients without anatomic pulmonary valve atresia can be deleterious. Circular shunts may develop in patients with different degrees of pulmonary and tricuspid insufficiency. Closure of the arterial duct may result in haemodynamic improvement in particular scenarios. The transcatheter approach is a valuable closure alternative despite some technical difficulties in large-sized arterial ducts and low birth weight neonates. Herein, we report on two consecutive term newborns with Ebstein's anomaly and large arterial ducts in whom mechanical stimulus of the arterial duct during failed attempts of transcatheter closure led after two days to definitive closure followed by good clinical outcomes.

4D flow magnetic resonance imaging to assess right ventricular outflow tract in patients undergoing transcatheter pulmonary valve replacement.

INTRODUCTION AND OBJECTIVES: Magnetic resonance imaging (MRI) including 4D flow is used before percutaneous pulmonary valve implantation (PPVI). As PPVI is limited by the size of the right ventricular outflow tract (RVOT), accurate sizing is needed to plan the intervention. The aim of this study was to compare different MRI modalities and invasive angiography to balloon sizing of RVOT. METHODS: Single-center prospective study of patients who underwent PPVI for isolated pulmonary regurgitation assessed by 4D flow MRI, 3D steady-state free precession/gradient echo (3D SSFP/GRE) and contrast magnetic resonance angiography. Balloon sizing was considered as the reference. RESULTS: A total of 23 adults were included (mean age, 38.4±12.5 years). Eighteen patients underwent successful primary PPVI. The average of the narrowest RVOT diameter was 25.4±4.3 mm by balloon sizing. Compared to balloon sizing, RVOT diameters were better correlated when estimated by systolic 4D flow MRI (r=0.89, P<.001) than by diastolic 4D flow MRI (r=0.71, P <.001), 3D contrast magnetic resonance angiography (r=0.73; P <.001) and 3D SSFP/GRE (r=0.50; P=.04) and was not significantly correlated when estimated by 2D in diastole and systole. The mean difference between systolic 4D flow MRI and balloon sizing was 0.2 mm (95%CI, -3.5 to 3.9 mm), whereas it was wider with other techniques. CONCLUSIONS: Beyond the quantification of pulmonary valve regurgitation, 4D flow allows accurate estimation of RVOT diameters, especially in systole, which is fundamental before planning PPVI.