Long-Term Effects of Pulmonary Valve Implantation and Prosthesis Evolution in Patients with Repaired Tetralogy of Fallot. / Efeitos de Longo Prazo do Implante Valvar Pulmonar e Evolução da Prótese em Pacientes com Tetralogia de Fallot Corrigida.

BACKGROUND: Pulmonary valve regurgitation is a significant long-term complication in patients with tetralogy of Fallot (TOF). OBJECTIVE: This study aims to investigate the effects of pulmonary valve implantation (PVI) on the anatomy and function of the right ventricle (RV) and the long-term evolution of the implanted prosthesis in the pulmonary position. METHODS: A single-center retrospective cohort analysis was performed in 56 consecutive patients with TOF who underwent PVI. The study included patients of both sexes, aged ≥ 12 years, and involved assessing clinical and surgical data, pre- and post-operative cardiovascular magnetic resonance imaging, and echocardiogram data more than 1 year after PVI. RESULTS: After PVI, there was a significant decrease in RV end-systolic volume indexed by body surface area (BSA), from 89 mL/BSA to 69 mL/BSA (p < 0.001) and indexed RV end-diastolic volume, from 157 mL/BSA to 116 mL/BSA (p < 0.001). Moreover, there was an increase in corrected RV ejection fraction [ RVEFC = net pulmonary flow (pulmonary forward flow - regurgitant flow) / R V end-diastolic volume ] from 23% to 35% (p < 0.001) and left ventricular ejection fraction from 58% to 60% (p = 0.008). However, a progressive increase in the peak pulmonary valve gradient was observed over time, with 25% of patients experiencing a gradient exceeding 60 mmHg. Smaller prostheses (sizes 19 to 23) were associated with a 4.3-fold higher risk of a gradient > 60 mmHg compared to larger prostheses (sizes 25 to 27; p = 0.029; confidence interval: 1.18 to 17.8). CONCLUSION: As expected, PVI demonstrated improvements in RV volumes and function. Long-term follow-up and surveillance are crucial for assessing the durability of the prosthesis and detecting potential complications. Proper sizing of prostheses is essential for improved prosthesis longevity.

Differences in Right Heart Function After Pulmonary Valve Replacement in Patients With Pulmonary Valve Stenosis Versus Tetralogy of Fallot.

BACKGROUND: There are limited data about the impact of timing of pulmonary valve replacement (PVR) on right heart reverse remodeling in patients with pulmonary regurgitation following intervention for isolated pulmonary valve stenosis (PS). This study compared differences in postprocedural right heart reverse remodeling after early versus late PVR (defined as PVR before versus after attainment of the conservative consensus criteria proposed by Bokma et al, 2018) in patients with prior intervention for PS, using patients with tetralogy of Fallot as the reference group. METHOD AND RESULTS: Right atrial reservoir strain and right ventricular free wall strain was measured at baseline, 1 and 3 years after PVR. There were 114 patients with PS (early PVR, 87 [76%]; late PVR, 27 [24%]) and 291 patients with tetralogy of Fallot (early PVR, 197 [67%]; late PVR, 96 [33%]). The PS group had greater improvement in right atrial reservoir strain at 1 year (12%±4% versus 8%±4%; P<0.001) and 3 years (15%±6% versus 9%±6%; P<0.001), and a greater improvement in right ventricular free wall strain at 1 year (12%±4% versus 7%±3%, P=0.008) and 3-years (16%±6% versus 12%±5%; P=0.01) after PVR compared with the tetralogy of Fallot group. There was no difference in right heart reverse remodeling between patients who underwent early versus later PVR within the PS group. In contrast, late PVR was associated with less right heart reverse remodeling within the tetralogy of Fallot group. CONCLUSIONS: These data suggest that patients with palliated PS presenting pulmonary regurgitation have a more benign clinical course, and hence delaying PVR in this population may be appropriate.

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.

Melody transcatheter pulmonary valve replacement: a single-center case series in Southeast Asia.

BACKGROUND: Studies of transcatheter pulmonary valve replacement (TPVR) with the Melody valve have demonstrated good clinical and hemodynamic outcomes. Our study analyzes the midterm clinical and hemodynamic outcomes for patients who underwent Melody valve implantation in Southeast Asia. METHODS: Patients with circumferential conduits or bioprosthetic valves and experiencing post-operative right ventricular outflow tract (RVOT) dysfunction were recruited for Melody TPVR. RESULTS: Our cohort (n = 14) was evenly divided between pediatric and adult patients. The median age was 19 years (8-38 years), a male-to-female ratio of 6:1 with a median follow-up period of 48 months (16-79 months), and the smallest patient was an 8-year-old boy weighing 18 kg. All TPVR procedures were uneventful and successful with no immediate mortality or conduit rupture. The primary implant indication was combined stenosis and regurgitation. The average conduit diameter was 21 ± 2.3 mm. Concomitant pre-stenting was done in 71.4% of the patients without Melody valve stent fractures (MSFs). Implanted valve size included 22-mm (64.3%), 20-mm (14.3%), and 18-mm (21.4%). After TPVR, the mean gradient across the RVOT was significantly reduced from 41 mmHg (10-48 mmHg) to 16 mmHg (6-35 mmHg) at discharge, p < 0.01. Late follow-up infective endocarditis (IE) was diagnosed in 2 patients (14.3%). Overall freedom from IE was 86% at 79 months follow-up. Three patients (21.4%) developed progressive RVOT gradients. CONCLUSION: For patients in Southeast Asia with RVOT dysfunction, Melody TPVR outcomes are similar to those reported for patients in the US in terms of hemodynamic and clinical improvements. A pre-stenting strategy was adopted and no MSFs were observed. Post-implantation residual stenosis and progressive stenosis of the RVOT require long term monitoring and reintervention. Lastly, IE remained a concern despite vigorous prevention and peri-procedural bacterial endocarditis prophylaxis.

Transcatheter-Based Interventions for Tetralogy of Fallot Across All Age Groups.

Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease. Palliative procedures, either surgical or transcatheter, aim to improve oxygen saturation, affording definitive procedures at a later stage. Transcatheter interventions have been used before and after surgical palliative or definitive repair in children and adults. This review aims to provide an overview of the different catheter-based interventions for TOF across all age groups, with an emphasis on palliative interventions, such as patent arterial duct stenting, right ventricular outflow tract stenting, or balloon pulmonary valvuloplasty in infants and children and transcatheter pulmonary valve replacement in adults with repaired TOF, including the available options for a large, dilated native right ventricular outflow tract.

The Ongoing Debate: Longevity of Biological Valves in Pulmonary Position.

BACKGROUND: In patients with tetralogy of Fallot (ToF) or ToF-like anatomy, factors possibly impacting the longevity of biological valves in the pulmonary position were investigated. METHOD: Between 1997 and 2017, 79 consecutive hospital survivors with a median age of 8.7 years (range: 0.2-56.1 years; interquartile range [IQR]: 14.8 years) with ToF or ToF-like anatomy underwent surgical implantation of Contegra (n = 34), Hancock (n = 23), Perimount (n = 9), pulmonary homograft (n = 9), and miscellaneous (n = 4) conduits. The median internal graft diameter was 19 mm (range: 11-29 mm; IQR: 8 mm) which refers to a median z-score of 0.6 standard deviation (SD) (range: -1.8 to 4.0 SD; IQR: 2.1 SD). RESULTS: The median time of follow-up was 9.4 years (range: 1.1-18.8 years; IQR: 6.0 years). Thirty-nine patients (49%) underwent surgical (n = 32) or interventional (n = 7) pulmonary valve re-replacement. Univariate Cox regression revealed patient age (p = 0.018), body surface area (p = 0.004), internal valve diameter (p = 0.005), and prosthesis z-score (p = 0.018) to impact valve longevity. Multivariate Cox regression analysis, however, did not show any significant effect (likely related to multicollinearity). Subgroup analysis showed that valve-revised patients have a higher average z-score (p = 0.003) and younger average age (p = 0.007). CONCLUSION: A decreased longevity of biological valves in the pulmonary position is related to younger age, lower valve diameter, and higher z-score. Because valve size (diameter and z-score) can be predicted by age, patient age is the crucial parameter influencing graft longevity.

Transcatheter Pulmonary Valve Replacement With the Harmony Valve in Patients Who Do Not Meet Recommended Oversizing Criteria on the Screening Perimeter Plot.

BACKGROUND: Anatomic selection for Harmony valve implant is determined with the aid of a screening report and perimeter plot (PP) that depicts the perimeter-derived radius along the right ventricular outflow tract (RVOT) and projects device oversizing. The PP provides an estimation of suitability for implant, but its sensitivity as a screening method is unknown. This study was performed to describe anatomic features and outcomes in patients who underwent Harmony TPV25 implant despite a PP that predicted inadequate oversizing. METHODS: We reviewed RVOT anatomic features and measurements in patients who underwent transcatheter pulmonary valve replacement with the Harmony TPV25 device despite a PP that predicted inadequate oversizing. RESULTS: This study included 22 patients. There were no unsuccessful implants or adverse valve-related events. Anatomic features varied, but all patients fit into 1 of 3 anatomic types characterized by differences in RVOT dimensions. Type 1 patients (n=9) had a long RVOT with a choke point and a wide main pulmonary artery. Type 2 patients (n=6) had a short RVOT that was pyramidal in shape, with no choke point, and extensive main pulmonary artery lengthening/expansion during systole. Type 3 patients (n=7) had a short, bulbous main pulmonary artery with a choke point and an open pulmonary artery bifurcation. CONCLUSIONS: Transcatheter pulmonary valve replacement with the Harmony valve is feasible in some patients whose PP fit analysis predicts inadequate oversizing. All cases in this series fit into 1 of 3 anatomic patterns, which are not identified in the screening report. Implanters must review cases individually to assess the feasibility of the implant.

Finite element modeling with patient-specific geometry to assess clinical risks of percutaneous pulmonary valve implantation.

BACKGROUND: Percutaneous pulmonary valve implantation (PPVI) is a non-surgical treatment for right ventricular outflow tract (RVOT) dysfunction. During PPVI, a stented valve, delivered via catheter, replaces the dysfunctional pulmonary valve. Stent oversizing allows valve anchoring within the RVOT, but overexpansion can intrude on the surrounding structures. Potentially dangerous outcomes include aortic valve insufficiency (AVI) from aortic root (AR) distortion and myocardial ischemia from coronary artery (CA) compression. Currently, risks are evaluated via balloon angioplasty/sizing before stent deployment. Patient-specific finite element (FE) analysis frameworks can improve pre-procedural risk assessment, but current methods require hundreds of hours of high-performance computation. METHODS: We created a simplified method to simulate the procedure using patient-specific FE models for accurate, efficient pre-procedural PPVI (using balloon expandable valves) risk assessment. The methodology was tested by retrospectively evaluating the clinical outcome of 12 PPVI candidates. RESULTS: Of 12 patients (median age 14.5 years) with dysfunctional RVOT, 7 had native RVOT and 5 had RV-PA conduits. Seven patients had undergone successful RVOT stent/valve placement, three had significant AVI on balloon testing, one had left CA compression, and one had both AVI and left CA compression. A model-calculated change of more than 20% in lumen diameter of the AR or coronary arteries correctly predicted aortic valve sufficiency and/or CA compression in all the patients. CONCLUSION: Agreement between FE results and clinical outcomes is excellent. Additionally, these models run in 2-6 min on a desktop computer, demonstrating potential use of FE analysis for pre-procedural risk assessment of PPVI in a clinically relevant timeframe.

Standardized Bench Test Evaluation of Biomechanical Characteristics of Stents Used in Right Ventricular Outflow Tract Revalvulation.

PURPOSE: Pre-stenting of the right ventricular outflow tract (RVOT) is commonly performed before percutaneous pulmonary valve implantation (PPVI), to relieve obstruction, prevent valved stent fractures, and provide a landing zone. This study aimed to evaluate the biomechanical characteristics of the stents currently used to perform pre-stenting of the RVOT. METHODS: We assessed five commercially available stents: Cheatham-Platinum Stent ("CP Stent"), AndraStent XL, AndraStent XXL, Optimus XL, and Optimus XXL. Following stent deployment at nominal pressure, radial and longitudinal elastic recoils and radial resistance were measured. The bending stiffness of the stents crimped onto the balloons was also evaluated. RESULTS: Three samples were tested for each stent. Our study showed no significant difference between the stent platforms in terms of radial elastic recoil, which was relatively low (< 10%). The longitudinal elastic recoil was also low for all the devices (< 5%). Significant differences were observed in radial resistance (P < 0.001). CP Stent and AndraStent XL exhibited the highest radial resistances. The bending stiffnesses of the stents crimped on their balloons were significantly different (P < 0.00001). Optimus XL and XXL were more flexible than the other stents. CONCLUSION: This study highlights the significant differences between the stents currently used in RVOT pre-stenting. Stents with good radial resistance are preferred, especially for calcified vessels, and flexibility is crucial for tortuous vessels. We proposed an algorithm for selecting the most suitable stent according to the need for radial force and flexibility, which will help inform clinicians considering RVOT revalvulation.

Growth of the right ventricular outflow tract in repaired tetralogy of Fallot: A longitudinal CMR study.

BACKGROUND: Many patients with repaired tetralogy of Fallot require pulmonary valve replacement (PVR) due to significant pulmonary regurgitation (PR). Transcatheter PVR (TPVR) is an equally effective and less invasive alternative to surgical PVR but many native right ventricular outflow tracts (RVOTs) are too large for TPVR at time of referral. Understanding the rate of growth of the RVOT may help optimize timing of referral. This study aims to examine the longitudinal growth of the native RVOT over time in repaired tetralogy of Fallot (TOF). METHODS: A retrospective review of serial cardiac MRI cardiovascular magnetic resonance (CMR) data from 121 patients with repaired TOF and a native RVOT (median age at first CMR 14.7 years, average interval between the first and last CMR of 8.1 years) was performed to measure serial changes in RVOT diameter, cross-sectional area, perimeter-derived diameter, and length. RESULTS: All parameters of RVOT size continued to grow with increasing age but growth was more rapid in the decade after TOF repair (for minimum systolic diameter, mean increase of 5.7 mm per 10 years up to year 12, subsequently 2.3 mm per 10 years). The RVOT was larger with a transannular patch and in patients without pulmonary stenosis (p < 0.001 for both), but this was not associated with rate of growth. More rapid RVOT enlargement was noted in patients with larger right ventricular end-diastolic volume (RVEDV), higher PR fraction, and greater rates of increases in RVEDV and PR (p < 0.001 for all) CONCLUSIONS: in patients with repaired TOF, using serial CMR data, we found that RVOT size increased progressively at all ages, but the rate was more rapid in the first decade after repair. More rapid RVOT enlargement was noted in patients with a larger RV, more PR, and greater rates of increases in RV size and PR severity. These results may be important in considering timing of referral for transcatheter pulmonary valves, in planning transcatheter and surgical valve replacement, and in designing future valves for the native RVOT.

Impact of Patient Prosthesis Mismatch on the Outcome of Transcatheter Pulmonic Valve Implantation.

Patient prosthesis mismatch (PPM) is an important factor of the outcome in transcatheter aortic valve implantation. However, the impact of PPM in transcatheter pulmonic valve implantation (TPVI) has not been studied. Based on the narrowest valve stent diameters in two views of fluoroscopy, internal geometric orifice area (GOA) of the valve stent was calculated and indexed by body surface area (BSA), deriving iGOA. To define PPM in TPVI, receiver operating characteristics (ROC) curve analysis for iGOA for predicting significant residual right ventricular outflow tract (RVOT) gradient was used to derive the optimal cut-off value of iGOA. Our cohort were divided into 2 groups: PPM versus non-PPM. The clinical data were compared between 2 groups. TPVI was performed using Melody valve in 101 patients. Significant RVOT residual pressure gradient (≥ 15 mmHg) was observed in 31 patients (39.6%). Over a mean follow up periods of 6.9 ± 2.7 years, 22 patients (21.8%) required repeat interventions (16 transcatheter, 11 surgical, and both in 5 patients). Based on the ROC analysis, the best cut-off value of iGOA was 1.25 cm2/m2 (area under the curve 0.873, p < 0.001) to define PPM. PPM was present in 42 patients (42%). On the Kaplan-Meier survival analysis, PPM was associated with the need of repeat intervention (p = 0.02). In conclusion, in TPVI, PPM was a strong predictor for the need of re-intervention. Considering PPM, target diameter of valve stent would depend on the patient body size and should be taken into account for optimal outcome of TPVI.

Outcomes in Young Adults With Tetralogy of Fallot and Pulmonary Annular Preserving or Transannular Patch Repairs.

BACKGROUND: Early surgical tetralogy of Fallot (ToF) repair involved patching across the pulmonic annulus (transannular patch [TAP] repair), which resulted in severe pulmonic regurgitation. Long-term outcome improvements were anticipated with modifications that preserved the pulmonic annulus (annulus-preserving [AP] repair). The objective of the present study was to evaluate the need for late reintervention in adults with AP repair and those with TAP repair. METHODS: We conducted a retrospective review of adults (born 1981-1996) with childhood intracardiac ToF repairs at a tertiary care center. The primary cardiovascular outcome was need for reintervention after primary intracardiac repair of ToF. Secondary outcomes included a composite of death, heart failure, and ventricular arrhythmias. RESULTS: Two hundred thirty adults were included: 104 with AP repair and 126 with TAP repair. The median age at last follow up was 25 years (interquartile range [IQR] 20-28) and the median follow-up duration was 7.9 years (IQR 3.5-12). Reintervention of any type was significantly more common in the TAP group during both childhood and adulthood (72.2% TAP vs 20.2% AP, HR 5.5, 95% CI 3.4-9.0; P < 0.001). Pulmonary valve replacement (PVR) was almost 6 times more likely in adults with TAP repair (65.1% TAP vs 16.3% AP, HR 5.7, 95% CI 3.4-9.7; P < 0.001). CONCLUSIONS: Patients who had AP ToF repair had significantly fewer late reinterventions compared with TAP repair, with the majority of reinterventions due to PVR. More long-term follow-up is required.

Congenital right ventricular diverticulum formed by pulmonary regurgitative jet flow in a fetus with tetralogy of Fallot and absent pulmonary valve.

Congenital ventricular diverticulum is a rare anomaly with an unclear pathology. Here, we report a male fetus at 24 weeks of gestation, diagnosed with right ventricular diverticulum associated with tetralogy of Fallot and absent pulmonary valve. The diverticulum was located at the anterosuperior wall of the right ventricle and faced into the massive pulmonary regurgitation flow jet. Intrauterine fetal death from heart failure resulted at 26 weeks of gestation. An autopsy revealed significant subendocardial fibrosis in the diverticular wall without inflammatory cell infiltration. Clinical and pathologic features suggested that the regurgitative blood flow contributed to the formation of the right ventricular diverticulum.