Right Ventricular Outflow Tract Conduit Research Articles

Durability of Aortic Homografts in Pulmonary Atresia and Major Aortopulmonary Collateral Arteries.

Objectives: It is well-known that right ventricle-to-pulmonary artery homograft conduit durability is worse for smaller conduits and smaller/younger patients. However, there is limited literature on age and conduit-size specific outcomes, or on the role of conduit oversizing. Methods: Patients diagnosed with tetralogy of Fallot and major aortopulmonary collateral arteries undergoing right ventricular outflow tract (RVOT) reconstruction with a valved aortic homograft conduit from November 2001 through March 2023, at our institution were included. Conduits were grouped and evaluated by diameter, diameter Z-score, and patient age at implant. The primary time-related outcome was freedom from RVOT reintervention. Factors associated with freedom from time-related outcomes were assessed with univariable Cox regression analysis. Results: A total of 863 RVOT conduits were implanted in 722 patients. On multivariable analysis, younger age, male sex, Alagille syndrome, smaller diameter of the conduit, and smaller Z-score were associated with shorter freedom from reintervention. Among patients with smaller diameter conduits, larger Z-scores were associated with longer freedom from conduit reintervention (P < .001). Transcatheter interventions were commonly used to extend conduit lifespan across ages and conduit sizes. Conclusions: Larger conduit diameter, older age, and higher conduit Z-score were associated with longer freedom from reintervention in patients undergoing RVOT reconstruction in this cohort. Oversizing of conduits, even beyond a Z-score of 4, is generally appropriate.

Flow pattern analysis of right ventricular outflow tract in repaired tetralogy of Fallot through 4D flow MRI.

Cardiac magnetic resonance imaging (CMR) often shows discrepancies between right ventricular outflow tract (RVOT) flow and left ventricular outflow tract flow in patients with late-stage repaired tetralogy of Fallot (rTOF), leading to potential errors in pulmonary regurgitation fraction (PRF) assessment. This study aimed to identify the conditions under which RVOT flow can be acutely evaluated using four-dimensional (4D) flow CMR. Twenty-seven consecutive patients with rTOF underwent both two-dimensional phase-contrast (2D PC) and 4D flow CMR between 2016 and 2018, excluding those with peripheral pulmonary artery stenosis, RVOT conduit replacement, unknown surgical method, and an aortic valve regurgitation greater than 20%. Seven healthy controls also underwent only 4D Flow CMR. All healthy controls and fifteen patients with rTOF showed laminar RVOT flow, while seven patients exhibited helical, and four patients exhibited vortical RVOT flow in 4D flow CMR visualization. Flow-volume concordance between the pulmonary artery and aortic flow was significantly lower in patients with rTOF and PRF > 40% in 2D PC CMR. This concordance rate in the suprapulmonary valve was high in both the TOF and control groups, comparing at five RVOT locations in 4D flow CMR. Regarding RVOT flow regurgitation in 4D flow, the whole bulk evaluation exhibited greater variation depending on the flow type compared to the whole pixel-wise evaluation. The study confirmed the flow volume at the upper section of the pulmonary valve as the most accurate correlate of aortic flow volume. Furthermore, the 4D flow CMR using the pixel-wise method demonstrated superior accuracy compared to the traditional bulk flow method.

Abstract P1059: Decellularization Of Valved Porcine Xenografts For Use In Pediatric Right Ventricular Outflow Tract Replacement Surgery

Introduction: The right ventricular outflow tract (RVOT) is pathologically affected in multiple congenital heart diseases, requiring surgical replacement within the first year of life. Shortage of small-sized homografts has driven xenograft use in pediatric cardiac surgery. However, these RVOT substitutes do not possess lifelong durability, eliciting high levels of inflammation and lacking growth potential. Xenograft limitations culminate in structural graft deterioration and rejection, resulting in invasive reoperations. Decellularization of donor tissue to eliminate cells and immunogenic antigens is a central method by which rejection risk can be diminished. Maintenance of the extracellular matrix (ECM) must be balanced with achievement of acellularity. Currently, no xenograft has proven optimal for pediatric RVOT surgical replacement; this work aims to produce a resilient and non-immunogenic decellularized porcine scaffold with translational capacity. Methods/Results: Research sought to optimize a combined chemical, enzymatic, and mechanical decellularization approach for RVOT conduits. The nine-day protocol utilizes a temperature-controlled bioreactor wherein EDTA, protease inhibitors, sodium dodecyl sulfate, and nucleases are circulated through the lumen of the submerged conduit. Maintenance of ECM structure, including elastin and collagen, in parallel with significant nuclei count reduction, removal of residual nucleic acids, and elimination of xenoantigens has been achieved. No significant difference was found between control and decellularized ventricular soluble collagen. All comparisons between samples processed directly after explant (fresh) and those decellularized following one freeze-thaw cycle (freeze-thawed) were not significantly different. Conclusion: Data indicate successful decellularization of valved conduits. Future work intends to seed mesenchymal stem cells onto the cell-free scaffold, improving biocompatibility and endowing the xenograft with growth potential. Decellularized RVOT xenografts provide a means to combat immunological mismatch between donor and patient, reducing the number of surgeries a child is exposed to and improving pediatric congenital surgery outcome.

Congenital Pulmonic Valve Dysfunction Treated With SAPIEN 3 Transcatheter Heart Valve (from the COMPASSION S3 Trial)

Significant pulmonary regurgitation (PR) and pulmonary stenosis are common after surgical repair of some congenital heart defects. This prospective, single-arm, multicenter trial enrolled patients who underwent transcatheter heart valve (THV) implantation with a SAPIEN 3 valve to treat dysfunctional right ventricular outflow tract (RVOT) conduits or pulmonic surgical valves (≥ moderate PR and/or mean RVOT gradient ≥35mm Hg). The primary end point was a nonhierarchical composite of THV dysfunction at 1year comprising RVOT reintervention, ≥ moderate total PR, and mean RVOT gradient >40mm Hg. A performance goal of <25% of upper confidence interval (CI) was prespecified for the primary end point, using a 95% exact binomial CI. Patients (n=58) were enrolled between July 5, 2016 and July 17, 2018, with mean age of 32years. Prestenting was performed in 53.4%. At discharge, the device success was 98.1% (single valve without explant, < moderate PR, gradient <35mm Hg). At 30days, there were no major adjudicated adverse clinical events. At 1year, the primary end point composite was 4.3% (95% CI 0.5 to 14.5). The composite components were 0% (0 of 56) RVOT reintervention, 2.1% (1 of 47) ≥ moderatePR, and 2.1% (1 of 48) mean RVOT gradient >40mm Hg. No mortality, endocarditis, thrombosis, or stent fracture were reported at 1year. In conclusion, the SAPIEN 3 THV was safe and effective in patients with dysfunctional RVOT conduits or previously implanted valves in the pulmonic position to 1 year. Clinical trial registration: NCT02744677; https://clinicaltrials.gov/ct2/show/NCT02744677.

First 10 transcatheter pulmonary valve-in-valve procedures in rajaie cardiovascular medical and research center

Background: Transcatheter pulmonary valves (TPVs) are feasible and much less invasive options for surgical right ventricular outflow tract (RVOT) repair or valve replacement in patients with degeneration of the pulmonary valve bioprosthesis or RVOT conduit failure. In 2005, the first Sapien valve was implanted in the pulmonic position, and proceeding In March 2016, the Food and Drug Administration approved the SAPIEN valve (Edwards Lifesciences) for use in malfunctioning RVOT conduits. Material and method: We describe the first ten cases of TPV-in-valve procedure conducted in our center, along with the patients' prior surgical history, procedural details, and their clinical and echocardiographic data. Result and conclusion: Our data provided safety and efficacy of transcatheter valve-in-valve procedure in degenerated pulmonary bioprotheses and our follow-up proved durability of this procedure.

Initial Clinical Trial of a Novel Pulmonary Valved Conduit

Valved allografts and xenografts for reconstruction of the right ventricular outflow tract (RVOT) lack durability and do not grow. We report the first clinical use of a completely bioabsorbable valved conduit (Xeltis pulmonary valve - XPV) in children. Twelve children (six male), median age five (two to twelve) years and median weight 17 (10 to 43) kg, underwent RVOT reconstruction with the XPV. Diagnoses were: pulmonary atresia with ventricular septal defect (VSD) (n = 4), tetralogy of Fallot (n = 4), common arterial trunk (n = 3), and transposition of the great arteries with VSD and pulmonary stenosis (n = 1). All had had previous surgery, including prior RVOT conduit implantation in six. Two diameters of conduit 16mm (n = 5) and 18mm (n = 7) were used. At 24 months none of the patients has required surgical re-intervention, 9 of the 12 are in NYHA functional class I and three patients in NYHA class II. None of the conduits has shown evidence of progressive stenosis, dilation or aneurysm formation. Residual peak gradient of >40 mm Hg was observed in three patients, caused by kinking of the conduit at implantation in 1 and distal stenosis in the peripheral pulmonary arteries in 2 patients. Five patients developed severe pulmonary valve insufficiency (PI); the most common mechanism was prolapse of at least one of the valve leaflets. The XPV conduit is a promising innovation for RVOT reconstruction. Progressive PI requires however an improved design (geometry, thickness) of the valve leaflets.

Abstract 13750: Cardiac Magnetic Resonance to Predict Coronary Artery Compression in Patients Undergoing Transcatheter Pulmonary Valve Implantation Into Conduits

Introduction: Transcatheter pulmonary valve implantation (TPVi) is a widely available option to treat right ventricular outflow tract (RVOT) conduits, but coronary artery compression is an absolute contraindication. Cardiac magnetic resonance (CMR) may evaluate coronary anatomy, but its utility in predicting coronary compression is not well established. Hypothesis: CMR prior to TPVi can accurately predict coronary compression risk. Methods: We analyzed all patients with a recent CMR (≤ 12 months) and attempted TPVi in an RVOT conduit at 9 centers from 2007-2016. A core lab reviewed all CMRs for the shortest orthogonal distance from a coronary artery to the conduit, the shortest distance from a coronary artery to the most stenotic area of the conduit, and subjective assessment of coronary compression risk. Receiver operating characteristic curve was used to determine optimal predictive distances. Univariate and independent associations of the distances and qualitative assessment with coronary compression were examined using logistic regression. Results: Of 231 patients (62% male, median age 19.0 years), TPVi was successful in 198 (86%); in 24 (10%) balloon testing (documented coronary compression or high risk) precluded implantation. Distance to the RV to PA conduit ≤ 2.1 mm (area under the curve [AUC] 0.70) and distance to most stenotic area ≤ 13.1 mm (AUC 0.69) predicted coronary compression (Table). Subjective assessment had the highest AUC (0.78), with 96% negative predictive value. Both distances and qualitative assessment remained independently associated with coronary compression when controlling for abnormal coronary anatomy. Conclusions: CMR can predict the risk of coronary compression during TPVi in RVOT conduits but cannot completely exclude the risk of coronary compression. CMR may assist in patient selection and counselling families prior to TPVi, although balloon testing prior to TPVi remains essential.

Computed tomography guided sizing for transcatheter pulmonary valve replacement

ObjectiveTo evaluate the predictive value of Computed Tomography Angiography (CTA) measurements of the RVOT for transcatheter valve sizing. BackgroundTranscatheter pulmonary valve replacement (TPVR) provides an alternative to surgery in patients with right ventricular outflow tract (RVOT) dysfunction. We studied 18 patients who underwent catheterization for potential TPVR to determine whether CT imaging can be used to accurately predict implant size. MethodsCases were grouped by RVOT characteristics: native or transannular patch (n = 8), conduit (n = 5) or bioprosthetic valve (n = 5). TPVR was undertaken in 14/18 cases, after balloon-sizing was used to confirm suitability and select implant size. Retrospective CT measurements of the RVOT (circumference-derived (Dcirc) and area-derived (Darea) diameters) were obtained at the level of the annulus, bioprosthesis or conduit. Using manufacturer sizing guidance, a valve size was generated and a predicted valve category assigned: (1) <18 mm, (2) 18–20 mm, (3) 22–23 mm, (4) 26–29 mm and (5) >29 mm. Predicted and implanted valves were compared for inter-rater agreement using Cohen’s kappa coefficient. ResultsThe median age of patients was 37 years old (IQR: 30–49); 55% were male. Diagnoses included: Tetralogy of Fallot (12/18), d-Transposition repair (3/18), congenital pulmonary stenosis (2/18) and carcinoid heart disease (1/18). Measurements of Darea (κ = 0.697, p < 0.01) and Dcirc (κ = 0.540, p < 0.01) were good predictors of implanted valve size. When patients with RVOT conduits were excluded, the predictive accuracy improved for Darea (κ = 0.882, p < 0.01) and Dcirc (κ = 0.882, p < 0.01). ConclusionsCT measurement of the RVOT, using Darea or Dcirc, can predict prosthetic valve sizing in TPVR. These measurements are less predictive in patients with conduits, compared to those with a native RVOT or pulmonic bioprosthesis. Condensed abstractWe studied 18 patients who underwent catheterization for TPVR to determine whether CT imaging could be used to accurately predict implant size. Retrospective RVOT measurements were used to generate a predicted valve size, which was compared with implanted valve size for inter-rater agreement. Measurements of Darea (κ = 0.697, p < 0.01) and Dcirc (κ = 0.540, p < 0.01) were good predictors of implanted valve size. When cases with RVOT conduits were excluded, the predictive accuracy improved for Darea (κ = 0.882, p < 0.01) and Dcirc (κ = 0.882, p < 0.01). CT measurement of the RVOT can accurately predict prosthetic valve sizing in TPVR. These measurements are less predictive in patients with conduits.

Pulmonary Valve Replacement for Tetralogy of Fallot.

Right ventricular outflow tract (RVOT) dysfunction is common following surgical repair of tetralogy of Fallot and other forms of complex congenital heart disease. This results in pulmonary stenosis or regurgitation and may ultimately lead to RV failure and dysrhythmias. Transcatheter valve technologies are now available to treat certain patients with RVOT dysfunction. Current devices include the Medtronic Melody valve and the Edwards Lifesciences SAPIEN XT. Although these valves are approved for use in dysfunctional circumferential RVOT conduits, they are increasingly being used off label for nonconduit outflow tracts. Procedural complications include but are not limited to conduit rupture and coronary compression. Longer-term complications include stent fracture and endocarditis. Outcomes with these valves have demonstrated durable relief of stenosis and regurgitation. The Medtronic Harmony valve and the Alterra Prestent from Edwards Lifesciences are investigational devices that are intended to treat the patulous RVOT that is too large to accommodate currently available valves. This review will focus on current indications to treat RVOT dysfunction, existing transcatheter valve technologies, and investigational devices undergoing clinical trials. Hopefully, within the not-too-distant future, transcatheter pulmonary valve implantation will be feasible in the vast majority of patients with RVOT dysfunction following surgical repair of congenital heart disease.

Technical Varieties of Ross Procedure: A Case Series.

Replacement of aortic valve with the pulmonary autograft is carried out through the Ross procedure due to its potential for growth, durability in pediatric population, and absence of anticoagulation. This case series reports the postoperative outcome of two technical variations of Ross procedure in eight patients who underwent surgery from January 2007 to December 2016. The dominant valvular hemodynamic indication was aortic regurgitation. The techniques employed for Ross procedure included free standing root replacement in six patients and modified root replacement with autograft stabilisation using Dacron interposition graft in two patients. Right ventricular outflow tract (RVOT) conduit reconstruction was achieved by utilisation of Contegra bio prosthesis in four patients; and use of manually constructed valved conduit comprising of PTFE (polytetrafluoroethelene) membrane and bovine pericardial tube in remaining four patients. There was no mortality and no re-intervention. The technical varieties of Ross procedure offer freedom from need of anti-coagulation, mortality, and RVOT conduit failure in younger adults.

Prediction of stenting related adverse events through patient-specific finite element modelling

Right ventricular outflow tract (RVOT) calcific obstruction is frequent after homograft conduit implantation to treat congenital heart disease. Stenting and percutaneous pulmonary valve implantation (PPVI) can relieve the obstruction and prolong the conduit lifespan, but require accurate pre-procedural evaluation to minimize the risk of coronary artery (CA) compression, stent fracture, conduit injury or arterial distortion.Herein, we test patient-specific finite element (FE) modeling as a tool to assess stenting feasibility and investigate clinically relevant risks associated to the percutaneous intervention.Three patients undergoing attempted PPVI due to calcific RVOT conduit failure were enrolled; the calcific RVOT, the aortic root and the proximal CA were segmented on CT scans for each patient. We numerically reproduced RVOT balloon angioplasty to test procedure feasibility and the subsequent RVOT pre-stenting expanding the stent through a balloon-in-balloon delivery system.Our FE framework predicted the occurrence of CA compression in the patient excluded from the real procedure. In the two patients undergoing RVOT stenting, numerical results were consistent with intraprocedural in-vivo fluoroscopic evidences. Furthermore, it quantified the stresses on the stent and on the relevant native structures, highlighting their marked dependence on the extent, shape and location of the calcific deposits. Stent deployment induced displacement and mechanical loading of the calcific deposits, also impacting on the adjacent anatomical structures.This novel workflow has the potential to tackle the analysis of complex RVOT clinical scenarios, pinpointing the procedure impact on the dysfunctional anatomy and elucidating potential periprocedural complications.

Pulmonary reinterventions after complete unifocalization and repair in infants and young children with tetralogy of Fallot with major aortopulmonary collaterals

BackgroundOur institutional approach to tetralogy of Fallot (TOF) with major aortopulmonary collaterals (MAPCAs) emphasizes unifocalization and augmentation of the reconstructed pulmonary arterial (PA) circulation and complete intracardiac repair in infancy, usually in a single procedure. This approach yields a high rate of complete repair with excellent survival and low right ventricular (RV) pressure. However, little is known about remodeling of the unifocalized and reconstructed pulmonary circulation or about reinterventions on the reconstructed PAs or the RV outflow tract conduit. MethodsWe reviewed patients who underwent complete repair of TOF with MAPCAs at our center at <2 years of age, either as a single-stage procedure or after previous procedures. Outcomes included freedom from conduit or PA intervention after repair, which were assessed by Cox regression and Kaplan–Meier analysis. ResultsThe study cohort included 272 patients. There were 6 early deaths and a median of follow-up of 3.6 years after complete repair. Reinterventions on the pulmonary circulation were performed in 134 patients, including conduit interventions in 101 patients, branch PA interventions in 101, and closure of residual MAPCAs in 9. The first conduit reintervention consisted of surgical conduit replacement in 77 patients, transcatheter pulmonary valve replacement with a Melody valve in 14, and angioplasty or bare metal stenting in 10. Surgical PA reinterventions were performed in 46 patients and transcatheter reinterventions in 75 (both in 20). Most PA reinterventions involved a single lung, and most transcatheter reinterventions a single vessel. Freedom from conduit replacement or transcatheter pulmonary valve replacement was 70 ± 3% at 5 years and was shorter in patients with smaller initial conduit size. Freedom from any PA reintervention was 64 ± 3% at 5 years, with the greatest rate during the first year. On multivariable analysis, factors associated with longer freedom from any PA reintervention included lower postrepair RV:aortic pressure ratio and larger original conduit size. ConclusionsWe were able to obtain follow-up data for the majority of patients, which demonstrated freedom from PA reintervention for two thirds of patients. The time course of and risk factors for conduit reintervention in this cohort appeared similar to previously reported findings in patients who received RV-PA conduits in early childhood for other anomalies. Relative to the severity of baseline pulmonary vascular anatomy in TOF with MAPCAs, reinterventions on the reconstructed PAs were uncommon after repair according to our approach, and major reinterventions were rare. Nevertheless, PA reinterventions are an important aspect of the overall management strategy.

23 Right ventricular outflow tract elan conduit: the five year scotland experience

Background The management of the right ventricular outflow tract (RVOT) is a common feature in congenital cardiac surgery. A number of valved conduits are available. We reviewed the outcomes of the Vascutek RVOT Elan Conduit in patients from a specialist congenital surgical centre. Methods Between 2010 and 2011, 25 patients (13 male, mean age: 25.5 years) received an Elan conduit in the RVOT position. 24 reported previous open cardiac surgery. Most common diagnosis was Tetralogy of Fallot (n=19 (76%)). Results The mean follow up period was 4.96 years. 24 (96%) patients were alive at the time of censorship. 16 adverse events were noted and defined as haemodynamically significant conduit and/or valve stenosis (n=12), death (n=1) and bacterial endocarditis (n=3). 12 (48%) patients required re-intervention (10 transcatheter pulmonary valve replacements [8 Medtronic Melody and 2 Edwards Sapien] and 2 surgical pulmonary homografts). Mean time to re-intervention 1.7 years (range 0.25 – 4.36 years) Conclusion This review of RVOT Elan conduits demonstrates that in a significant proportion of patients there is short interval to re-intervention due to haemodynamically significant conduit and/or valve stenosis. (Figures 1 and 2) The conduit was technically attractive for transcatheter intervention. Other centres have published favourable results in the first 12 months after surgery. There are no other reported outcomes after this period. Our review suggests that ongoing frequent clinical assessment is required and should continue beyond the first 12 months. The Elan conduit is no longer in production and the search for the ideal valved RVOT conduit continues at a time when homograft availability is becoming an increasing challenge.

Transcatheter Pulmonary Valve Replacement for Right Ventricular Outflow Tract Conduit Dysfunction After the Ross Procedure

Right ventricular outflow tract (RVOT) conduit dysfunction is a limitation of the Ross procedure. Transcatheter pulmonary valve replacement (TPVR) could alter the impact of conduit dysfunction and the risk-benefit balance for the Ross procedure. Retrospective review of databases from 3 prospective Melody TPV (Medtronic Inc, Minneapolis, MN) trials. Among 358 patients who were catheterized with the intent to implant a Melody TPV for RVOT conduit stenosis or regurgitation (PR) as part of 3 prospective multicenter studies, 67 (19%) had a prior Ross procedure. Of these, 56 (84%) received a Melody valve; in 5 of the 11 patients who did not, the implant was aborted due to concern for coronary artery compression, and 1 implanted patient required emergent surgery for left coronary compression. The RVOT gradient decreased from a median 38 mm Hg to 13.5 mm Hg (p < 0.001). There was no or trivial PR in all but 4 patients, in whom it was mild. At a median follow-up of 4.0 years, 1 patient died from sepsis. Twelve patients underwent 14 transcatheter (n= 8) or surgical (n= 6) TPV reinterventions for obstruction with stent fracture (n= 9), endocarditis with conduit obstruction (n= 3), or reoperation (n= 2). Freedom from TPV explant was 89% ± 5% at 4 years. Among patients who did not undergo reintervention for obstruction, there was no change in RVOT gradient over time, and all but 1 patient had mild or less PR at last follow-up. The TPVR with the Melody valve provides acceptable early outcomes and durable valve function in the majority of Ross patients. Recurrent RVOT obstruction associated with stent fracture was the main reason for reintervention. Coronary compression is not uncommon in Ross patients and should be assessed prior to TPVR.

One-year follow-up of the Melody transcatheter pulmonary valve multicenter post-approval study.

This study sought to confirm that the short-term hemodynamic effectiveness of the Melody transcatheter pulmonary valve (TPV) (Medtronic, Inc., Minneapolis, Minnesota) achieved by real-world providers is equivalent to thehistorical results established in the initial 5-center Investigational Device Exemption trial. TPV replacement has been used to treat right ventricular outflow tract (RVOT) conduit dysfunction for >10 years. The Melody TPV received U.S. Food and Drug Administration approval in 2010 as a Humanitarian Use Device. Patients with dysfunctional RVOT conduits were entered in this prospective, nonrandomized study at 10 centers. The primary endpoint was acceptable hemodynamic function at 6 months post-implantation, defined as a composite of RVOT echocardiographic mean gradient≤30 mmHg, pulmonary regurgitation less than moderate as measured by echocardiography, and freedom from conduit reintervention and reoperation. Cardiac catheterization was performed in 120 patients for potential implantation of the Melody TPV; of these, 100 patients were implanted, with a 98.0% procedural success rate. There were no procedure-related deaths. Acceptable hemodynamic function at 6 months was achieved in 96.7% of patients with evaluable data (87.9% of the entire implanted cohort), with results maintained through 1 year. No patient had moderate or severe pulmonary regurgitation after implantation. No patient required catheter reintervention in the first year after implantation, and 2 patients required reoperation for conduit replacement. The rate of freedom from TPV dysfunction was 96.9% at 1 year. This first prospective, real-world experience with the Melody TPV in the United States demonstrates continued high procedural success, excellent short-term TPV function, and low reintervention and reoperation rates at1year. (Melody Transcatheter Pulmonary Valve Post-Approval Study; NCT01186692).

NuMED Covered Cheatham-Platinum Stent™ for the treatment or prevention of right ventricular outflow tract conduit disruption during transcatheter pulmonary valve replacement.

Retrospectively assess the frequency of right ventricular outflow tract (RVOT) conduit disruption during transcatheter pulmonary valve replacement (TPVR) and the effectiveness and safety of NuMED Covered Cheatham-Platinum Stents™ (CCPS) for its prevention or treatment. There have been no published reports to date describing the safety and effectiveness of covered stents to prevent or treat RVOT conduit disruption during TPVR. Data regarding 251 TPVR procedures performed at multiple US investigational sites were retrospectively reviewed to explore the incidence and potential predictors of conduit disruption. In addition, data on the use of 69 CCPS implanted in 50 patients during TPVR was reviewed. The overall incidence of conduit disruption requiring intervention was 6%. The only predictor identified was a very elevated RVOT conduit systolic pressure gradient. A pre-existing conduit tear was present in nine, while 31 developed tears after conduit dilation and three, after TPVR. The CCPS was used prophylactically in seven. Conduit tears were prevented or repaired in 49/50 patients. No CCPS-related acute complications were reported. At 6-month follow-up, no patient had more than mild pulmonary regurgitation and the mean Doppler RVOT gradient (12.7 ± 5.8 mm Hg) comparing favorably with that reported in the Melody TPV® IDE trial (20.0 ± 8.6 mm Hg). CCPS implantation can successfully treat RVOT conduit disruption without negative impact on the TPV function. This retrospective analysis suggests high RVOT conduit systolic pressure gradient is a risk factor for conduit tears during TPVR.

Effects of Transcatheter Pulmonary Valve Replacement on the Hemodynamic and Ventricular Response to Exercise in Patients With Obstructed Right Ventricle-to-Pulmonary Artery Conduits

This study sought to investigate the effects of exercise on the right ventricle in patients with an obstructed right ventricular outflow tract (RVOT) conduit before and after transcatheter pulmonary valve replacement (TPVR). Conventionally, assessment of the right ventricle in congenital heart disease patients with dysfunctional RVOT conduits is performed at rest. However, this does not reflect dynamic exercise changes. Exercise stress echocardiography (ESE) before and 6 months after TPVR was performed. ESE protocol included measurement of rest and immediate post-exercise RVOT maximal instantaneous gradients (MIGs), right ventricular (RV) systolic pressure, 2-dimensional fractional area change, and global longitudinal strain (GLS). Twenty patients with RVOT conduit obstruction (median age, 18 years), the majority (n = 14) with tetralogy of Fallot, completed the study. Pre-TPVR, the median resting MIG across the RVOT was 53 mm Hg (23 to 95 mm Hg) and increased to 93 mm Hg (49 to 156 mm Hg; p < 0.001) with exercise. After TPVR, the median MIG at rest was 26 mm Hg (6 to 41 mm Hg, and after exercise, it was 45 mm Hg (9 to 102 mm Hg), both significantly lower than before TPVR (p ≤ 0.001), but there was still a substantial increase in gradient with exercise in many patients. The RV fractional area change, RV GLS, and left ventricular GLS, both at rest and after exercise, were significantly greater after TPVR than before. A greater pre-TPVR exercise-related increase in RV function was associated with improvement in peak Vo2 after TPVR (p = 0.01). In patients with obstructed RVOT conduits, TPVR resulted in significant improvement in conduit stenosis and RV function at both rest and at peak exercise and in exercise cardiopulmonary function. The ability to augment RV function at peak exercise before TPVR was associated with improved exercise capacity 6 months after TPVR.

Size matters: Longevity of valved RVOT conduits is mainly related to the conduit diameter

Objectives: Reconstruction of the right ventricular outflow tract (RVOT) deemed necessary in many cardiac anomalies and is the most frequent surgical procedure in adults with congenital heart disease. RVOT reconstruction is often facilitated with a valved conduit; however, the type of conduit is still a matter of debate, as are the factors affecting its longevity.

A new strategy to identify potentially dangerous coronary arterial patterns before percutaneous pulmonary valve implantation.

Despite advances in surgical techniques, right ventricular outflow tract (RVOT) conduits are prone to fail over time. Percutaneous pulmonary valve implantation was introduced to expand the lifetime of these conduits and to decrease the number of open heart operations during a patient's lifetime. The procedure can be performed with excellent results; however, serious complications such as coronary arterial compression and conduit rupture have been reported. We present percutaneous treatment of a patient after Ross-Konno operation with RVOT conduit dysfunction and a potentially problematic course of the left anterior descending artery.

Abstract 17306: Right Ventricular Response to Exercise in Patients with an Obstructed Right Ventricle-to-Pulmonary Artery Conduit: Effects of Transcatheter Pulmonary Valve Replacement

Background: In patients with repaired congenital heart disease, the clinical evaluation of right ventricular outflow tract (RVOT) conduit dysfunction (i.e. stenosis or regurgitation) has classically involved analysis of anatomic and physiologic changes of the right ventricle (RV) at rest. Such evaluation does not reflect dynamic changes that occur during exercise, or elicit functional changes in response to physiologic stress. In this study, we characterized the physiologic effects of exercise on the RV in patients with an obstructed RVOT conduit before and after transcatheter pulmonary valve replacement (TPV). Methods: Patients with RVOT conduit obstruction who underwent TPV between March 2010- March 2011 at Children's Hospital Boston were enrolled. Exercise echocardiograms were performed in all patients. Rest and peak exercise RVOT gradient, RV systolic pressure, and 2D global longitudinal RV strain parameters (composite of 6-segment RV strain from a 4-chamber apical view via speckled tracking) were obtained prior to and 6 months post-TPV. Results: A total of 12 patients, of whom 8 had Tetralogy of Fallot (67%) were enrolled and completed the study. Median age at the time of TPV was 18 yrs (range 4 - 28). Prior to TPV, the median resting maximum instantaneous gradient (MIG) was 60mmHg (range 32-85) and increased with peak exercise to 95 mmHg (range 50 -156; p&lt;0.001). At baseline, resting global RV strain was -15% (-6, 19.6) and increased to -17% (-3, -22; p =0.005) at peak exercise. Following TPV, median MIG declined significantly at rest to 21mmHg (range 16-41; p= 0.03 vs. pre-TPV) and at peak exercise, 41mmHg (range 27-81; p=0.03 vs. pre-TPV), but still with a significant increase in MIG from rest to peak exercise (p&lt;0.001). Following TPV, global RV strain increased at rest,-17% (-2, -24; p= 0.005), and further at peak exercise, -20% (-6, -23; p=0.01). Conclusions: Exercise led to a significant increase in the peak RVOT gradient and global longitudinal RV strain both before and after TPV. TPV resulted in significantly improved RVOT gradient and longitudinal RV myocardial deformation both at rest and during peak exercise.