Right ventricular outflow tract obstruction in twin-to-twin transfusion syndrome undergoing laser surgery: A systematic review and meta-analysis.

INTRODUCTION: We aimed to investigate the incidence, prenatal factors and outcomes of twin-to-twin transfusion (TTTS) with right ventricular outflow tract obstruction (RVOTO). MATERIAL AND METHODS: A systematic search was conducted to identify relevant studies published until February 2023 in English using the databases PubMed, Scopus and Web of Science. Studies reporting on pregnancies with TTTS and RVOTO were included. The random-effect model pooled the mean differences or odds ratios (OR) and the corresponding 95% confidence intervals. Heterogeneity was assessed using the I2 value. RESULTS: A total of 17 studies encompassing 4332 TTTS pregnancies, of which 225 cases had RVOTO, were included. Incidence of RVOTO at time of TTTS diagnosis was 6%. In all, 134/197 (68%) had functional pulmonary stenosis and 62/197 (32%) had functional pulmonary atresia. Of these, 27% resolved following laser and 55% persisted after birth. Of those persisting, 27% required cardiac valve procedures. Prenatal associations were TTTS stage III (53% vs 39% in no-RVOTO), stage IV TTTS (28% in RVOTO vs 12% in no-RVOTO) and ductus venosus reversed a-wave (60% in RVOTO vs 19% in no-RVOTO). Gestational age at laser and gestational age at delivery were comparable between groups. Survival outcomes were also comparable between groups, including fetal demise of 26%, neonatal death of 12% and 6-month survival of 82% in RVOTO group. Findings were similar when subgroup analysis was done for studies including head-to-head analysis. CONCLUSIONS: RVOT occurs in about 6% of the recipient twins with TTTS, especially in stages III and IV and those with reversed ductus venosus a-wave. The findings from this systematic review support the need for a thorough cardiac assessment of pregnancies complicated by TTTS, both before and after laser, to maximize perinatal outcome, and the importance of early diagnosis of TTTS and timely management.

Right Ventricular Outflow Tract Obstruction by an Aneurysm of the Ventricular Membranous Septum: A Systematic Review of Case Reports.

We performed a literature search to identify the details of patients with right ventricular outflow tract obstruction caused by an aneurysm of the ventricular membranous septum in a perimembranous ventricular septal defect. Thirty-one cases with a median age of 29 years (range, 1-69 years) were studied. A right ventricle-pulmonary artery systolic pressure gradient ranged from 35 to 107 mm Hg (mean 69 mm Hg). An interventricular shunt was absent in eight patients: two children and six adults. It is necessary to monitor the size of an aneurysm of the ventricular membranous septum, whether or not an interventricular shunt is present.

A surgical mouse model of neonatal right ventricular outflow tract obstruction by pulmonary artery banding.

BACKGROUD: Diseased animal models play an extremely important role in preclinical research. Lacking the corresponding animal models, many basic research studies cannot be carried out, and the conclusions obtained are incomplete or even incorrect. Right ventricular (RV) outflow tract (RVOT) obstruction leads to RV pressure overload (PO) and reduced pulmonary blood flow (RPF), which are 2 of the most important pathophysiological characteristics in pediatric cardiovascular diseases and seriously affect the survival rate and long-term quality of life of many children. Due to the lack of a neonatal mouse model for RVOT obstruction, it is largely unknown how RV PO and RPF regulate postnatal RV and pulmonary development. The aim of this study was to construct a neonatal RVOT obstruction mouse model. METHODS AND RESULTS: Here, we first introduced a neonatal mouse model of RVOT obstruction by pulmonary artery banding (PAB) on postnatal day 1. PAB induced neonatal RVOT obstruction, RV PO, and RPF. Neonatal RV PO induced cardiomyocyte proliferation, and neonatal RPF induced pulmonary dysplasia, the 2 features that are not observed in adult RVOT obstruction. As a result, PAB neonates exhibited overall developmental dysplasia, a sign similar to that of children with RVOT obstruction. CONCLUSIONS: Because many pediatric cardiovascular diseases are associated with RV PO and RPF, the introduction of a neonatal mouse model of RVOT obstruction may greatly enhance our understanding of these diseases and eventually improve or save the lives of many children.

Stenting of native right ventricular outflow tract obstructions in symptomatic infants: histological work-up of explanted specimen.

BACKGROUND: Stenting of stenotic right ventricular outflow tract is a palliative measure for severely impaired small babies with Tetralogy of Fallot or similar pathologies. Little is known about the histopathological fate of the stents in the right ventricular outflow tract. METHODS: Eight samples of surgically removed right ventricular outflow tract stents were histologically analysed according to a predefined protocol. RESULTS: The most frequent diagnosis was Tetralogy of Fallot in four patients, pulmonary atresia with ventricular septal defect in two patients, double outlet right ventricle with pulmonary obstruction in one patient, and muscular obstruction of the right ventricular outflow tract in one patient with a syndromic disease with hypertrophic cardiomyopathy. Stents mean implantation duration was 444 days ranging from 105 to 1117 days (median 305.5 days). Histology revealed a variable degree of pseudointima formation consisting of fibromuscular cells surrounded by extracellular matrix. Four of the specimen contained adjacent myocardial tissue fragments, which showed regressive changes. Neither myocardium nor pseudointima tissue or tissue parts locally related to stent struts were infiltrated by inflammatory cells. CONCLUSIONS: Histological analysis after explantation of early-in-life implanted right ventricular outflow tract stents revealed predominantly pronounced neo-intimal proliferation with a visible endothelial layer, no signs of inflammation, and no prolapse of muscular tissue through the stent struts. Thus, implantation of stents in early life seems to interfere little with the hosts' immune system and might help to open up the right ventricular outflow tract by mechanical forces and regressive changes in adjacent muscular tissue.

Long-term outcomes of tetralogy of Fallot repair: A 30-year experience with 960 patients.

OBJECTIVE: This study evaluates the long-term results of tetralogy of Fallot repair and assesses the risk factors for adverse outcomes. METHODS: This retrospective study included 960 patients who underwent transatrial transpulmonary tetralogy of Fallot repair between 1990 and 2020. RESULTS: A transannular patch was placed in 722 patients, and pulmonary valve preservation was achieved in 233 patients. The median age at tetralogy of Fallot repair was 9.4 (interquartile range, 6.2-14.2) months. The median follow-up duration was 10.6 (interquartile range, 5.4-16.3) years. There were 8 early deaths (0.8%) and 20 late deaths (2.1%). Genetic syndrome and pulmonary valve annulus Z score less than -3 were risk factors for mortality. The survival was 97.7% (95% confidence interval, 96.4-98.5) and 94.5% (95% confidence interval, 90.9-96.7) at 10 and 30 years, respectively. Freedom from any reoperation was 86.4% (95% confidence interval, 83.6-88.7) and 65.4% (95% confidence interval, 59.8-70.4) at 10 and 20 years, respectively. Postoperative right ventricular outflow tract peak gradient of 25 mm Hg or greater correlated with reoperation. Propensity score-matched analysis demonstrated that freedom from pulmonary valve replacement at 15 years was higher in the pulmonary valve preservation group compared with the transannular patch group (98.2% vs 78.4%, P = .004). Freedom from reoperation for right ventricular outflow tract obstruction at 15 years was lower in the pulmonary valve preservation group compared with the transannular patch group (P = .006). CONCLUSIONS: The long-term outcomes of tetralogy of Fallot repair are excellent. A postoperative right ventricular outflow tract peak gradient less than 25 mm Hg appears to be optimal to prevent reoperation. If the pulmonary valve size is suitable, pulmonary valve preservation reduces the risk of pulmonary valve replacement, yet increases the reoperation rate for right ventricular outflow tract obstruction.

Right ventricular outflow tract obstruction associated with neointimal tissue accumulation and distortion of the Harmony TPV25 stent frame: Potential mechanisms and treatment.

BACKGROUND: The Harmony TPV25 transcatheter pulmonary valve (Medtronic Inc.) is constructed with a self-expanding stent frame comprising six zigged nitinol wires sewn together and covered with knitted polyester fabric, with flared inflow and outflow ends and a porcine pericardial valve sutured to the central portion of the device. It was approved for treatment of pulmonary regurgitation after prior right ventricular outflow tract repair in 2021. Early outcomes of this procedure have been excellent, but little is known about valve durability or ultimate mechanisms of dysfunction. METHODS: We collected data on patients who underwent reintervention for TPV25 dysfunction and described findings related to distortion of the stent frame and tissue accumulation. RESULTS: We describe six patients who underwent valve-in-valve implant for TPV25 obstruction (peak catheterization gradient peak 28-73 mmHg) 10-28 months after implant. In all cases, there was tissue accumulation within the inflow and valve-housing segments of the device and deformation of the self-expanding valve frame characterized by variable circumferential narrowing at the junction between the valve housing and the inflow and outflow portions of the device, with additional geometric changes in all segments. All six patients underwent valve-in-valve implant that results in a final peak gradient ≤10 mmHg and no regurgitation. DISCUSSION: The occurrence of short-term Harmony TPV25 dysfunction in multiple patients with a similar appearance of frame distortion and tissue accumulation within the inflow and valve housing portions of the device suggests that this may be an important failure mechanism for this valve. Potential causes of the observed findings are discussed. It is possible to treat this mechanism of TPV25 dysfunction with valve-in-valve implant using balloon expandable transcatheter valves.

A Stent Misplaced in the Septal Perforating Artery: Right Ventricular Fistula, Interventricular Septal Hematoma, and Right Ventricular Outflow Tract Obstruction. / Um Stent Mal Colocado na Artéria Septal Perfurante: Fístula Ventricular Direita, Hematoma do Septo Interventricular e Obstrução da Via de Saída do Ventrículo Direito.

Coronary-cameral fistulas, though mostly regarded as congenital entities, have also been encountered as complications of major traumas and percutaneous coronary interventions (PCIs).1 On the other hand, interventricular septal (IVS) hematoma might potentially arise mostly during retrograde chronic total occlusion (CTO) interventions and has a benign course in this context.2 Herein, we describe a challenging PCI complication (and its management strategy) presenting with IVS hematoma, right ventricular fistula, and right ventricular outflow tract (RVOT) obstruction due to a misimplanted coronary stent in the septal perforating artery (SPA).

As fístulas coronário-camerais, embora consideradas em sua maioria como entidades congênitas, também têm sido encontradas como complicações de grandes traumas e intervenções coronárias percutâneas (ICPs).1 Por outro lado, o hematoma do septo interventricular (SIV) pode potencialmente surgir principalmente durante intervenções de oclusão total crônica retrógrada (OTC) e tem um curso benigno nesse contexto.2 Aqui, descrevemos uma complicação desafiadora da ICP (e sua estratégia de manejo) apresentando hematoma do SIV, fístula ventricular direita e obstrução da via de saída do ventrículo direito (VSVD) devido a um stent coronário mal implantado na artéria septal perfurante (ASP).

Unmet Clinical Needs for Transcatheter Pulmonary Valves.

A common feature of congenital heart disease is the presence of right ventricular outflow tract (RVOT) obstruction that can range from mild to severe and can lead to atresia of the pulmonary valve, in extreme conditions. RVOT abnormalities can frequently be corrected surgically or via interventional means. However, most of these patients will ultimately develop pulmonary valve insufficiency and eventual right ventricular dilation, which will require a pulmonary valve replacement at some point in their life to mitigate the detrimental effects of pulmonary valve regurgitation (PVR) on the right ventricle (RV). The evolution from the studies done by Philip Bonhoeffer to implant a pulmonary valve via transcatheter means, have provided a bedrock for transcatheter pulmonary valve replacement (TPVR). Yet, several areas of unmet need for a demographic of patients still exist. Here, we discuss the clinical unmet needs in children under 20 Kg and expand the use of hybrid and other TPVR approaches along with the current indications and contraindications for pulmonary valve replacement. The constraints and limitations from commercially available pulmonary valves will be discussed from a clinical standpoint. Finally, we explore the use of hybrid and periventricular delivery of transcatheter pulmonary valves in younger patients.

Managing Myocardial Bridge and Right Ventricular Outflow Tract Obstruction in an Adolescent With Hypertrophic Cardiomyopathy.

We report a case of symptomatic myocardial bridge in an adolescent with dynamic right ventricular outflow tract obstruction and history of congenital pulmonary valve stenosis as well as hypertrophic cardiomyopathy. Definitive treatment was surgical infundibular myectomy and coronary unroofing, resulting in improvement in right ventricular outflow tract gradient and ischemic symptoms.

Hipertrofia grave del ventrículo derecho secundaria a estenosis valvular pulmonar en lactante mayor con síndrome de Noonan: reporte de caso / Severe right ventricular hypertrophy secondary to pulmonary valve stenosis in an older infant with Noonan syndrome: a case report

Introducción: El Síndrome de Noonan se caracterizada por alteraciones del crecimiento, retraso psicomotor y mental, dismorfia facial, alteraciones musculo-esqueléticas y alteraciones cardíacas hasta en el 80 % de los pacientes, miocardiopatía hipertrófica 30%, estenosis valvular pulmonar 50 % y defectos septales, estenosis de ramas pulmonares, tetralogía de Fallot o coartaciones aórticas. Caso clínico: lactante de 8 meses con hipertelorismo, ptosis palpe-bral, orejas con implantación baja, cuello corto y escoliosis. Se presenta con cianosis y disnea asociada a hipotonía muscular. Peso: score Z: -3, talla: score Z: -3, a la auscultación cardiaca: soplo meso-sistólico grado 4/6 en segundo espacio intercostal izquierdo, línea para-esternal. En el ecocardiograma se observa estenosis pulmonar valvular de grado moderado (gradiente sistólico de 52 mmHg) y dilatación del tronco arterial pulmonar. Evolución: Se efectúa cateterismo cardíaco con evidencia estenosis valvular pulmonar grave, reacción infundibular, hipertrofia del ventrículo derecho, apertura valvular en domo y conducto arterioso persistente filiforme "tipo E", estos hallazgos justificaban el desarrollo de hipertrofia cardíaca. Se realizó una valvuloplastia pulmonar con balón que mejoró las presiones cardíacas. Conclusiones: Las alteraciones cardíacas presentes en un lactante con síndrome de Noonan fueron: Hipertrofia biventricular, hipertensión pulmonar, estenosis valvular pulmonar, conducto arterioso persistente.

Introduction: Noonan syndrome is characterized by growth disorders, psychomotor and mental retardation, facial dysmorphia, musculoskeletal disorders, and cardiac disorders in up to 80% of patients, hypertrophic cardiomyopathy in 30%, pulmonary valve stenosis in 50%, septal defects, pulmonary branch stenosis, tetralogy of Fallot, and aortic coarctations. Clinical case: 8-month-old infant with hypertelorism, palpebral ptosis, low-set ears, short neck, and scoliosis. It presents with cyanosis and dyspnea associated with muscle hypotonia. Weight: Z score: -3, height: Z score: -3, on cardiac auscultation: mid-systolic murmur grade 4/6 in the second left intercostal space, parasternal line. The echocardiogram shows moderate valvular pulmonary stenosis (52 mmHg systolic gradient) and dilatation of the pulmonary arterial trunk. Evolution: Cardiac catheterization was performed with evidence of severe pulmonary valve stenosis, infundibular reaction, right ventricular hypertrophy, dome valve opening, and "type E" filiform patent ductus arteriosus. These findings justified the development of cardiac hypertrophy. Pulmonary balloon valvuloplasty was performed, which improved cardiac pressure. Conclusions: The cardiac alterations present in an infant with Noonan syndrome were biventricular hypertrophy, pulmonary hypertension, pulmonary valve stenosis, and patent ductus arteriosus.

Evolution of Pulmonary Valve Management During Repair of Tetralogy of Fallot: A 14-year Experience.

BACKGROUND: The optimal repair strategy for tetralogy of Fallot remains controversial. This report presents a 14-year evolution of management of the pulmonary valve (PV) from transannular patch to valve-sparing repair to neovalve creation using living right atrial appendage tissue. METHODS: A retrospective review of 172 consecutive patients undergoing complete repair for TOF between January 2007 and June 2021 was performed. Clinical and follow-up data were analyzed by repair group. Neopulmonary valve (NPV) creation using right atrial appendage tissue was introduced in 2019. Failure of valve-sparing repair was defined as needing reintervention for recurrent right ventricular outflow tract obstruction (RVOTO). RESULTS: Median age and weight at repair were 4.9 months and 6 kg, respectively. Median preoperative PV size and z-score were 6.4 mm (5.2-8.3 mm) and -3.2 (-4.1 to -2.1), respectively. Patients who underwent valve-sparing repair had larger PV size and z-score compared with patients who underwent transannular patch procedures (8 mm vs 5.6 mm; -2.1 vs -3.2; both P < .001). There were no hospital mortalities. Overall follow-up was 44 months. At last follow-up, 10% of patients who underwent valve-sparing repair had repeat intervention for recurrent RVOTO. Patients who had failed valve-sparing repair had significantly lower PV z-scores (-2.6 vs -1.9; P = .01). An NPV was used in 8 patients with a median PV z-score of -4 (-4.7 to -3.9). At 6 months, 6 patients (75%) had mild or trivial pulmonary insufficiency after NPV placement. CONCLUSIONS: Repair of tetralogy of Fallot is a safe operation with excellent outcomes. Valve-sparing repair avoids right ventricular dilation but may fail for RVOTO at a PV z-score <-2. NPV creation offers an alternative option in patients with a small PV.