Transcatheter pulmonary valve replacement after arterial switch operation.

BACKGROUND: Patients with d-transposition of the great arteries (d-TGA) who have undergone an arterial switch operation (ASO) can develop right ventricular outflow tract (RVOT) dysfunction with pulmonary regurgitation (PR) or stenosis. In these patients, treatment may include transcatheter pulmonary valve replacement (TPVR). Coronary compression is a contraindication occurring in 5% of typical TPVR cases. After ASO, there are various anatomical considerations that can confound TPVR, including potential coronary artery compression. Our goal is to understand feasibility of TPVR in patients following ASO. METHODS: This was a retrospective multicenter cohort study of patients with RVOT dysfunction after ASO who underwent cardiac catheterization with intention to perform TPVR from 2008 to 2020. RESULTS: Across nine centers, 33 patients met inclusion criteria. TPVR was successful in 22 patients (66%), 19 receiving a Melody valve and 3 a SAPIEN valve. RVOT stenosis in isolation or with PR dictated need for TPVR in nearly all patients. One serious adverse event occurred with valve embolization. After TPVR, the RVOT peak gradient decreased from 43 to 9 mm Hg (p < 0.001); PR was trivial/none in all but one patient, in whom it was mild. Coronary compression prohibiting TPVR occurred in eight patients (24%) and two patients (6%) had severe aortic regurgitation from aortic root deformation precluding TPVR. Seven patients underwent RVOT reintervention with a median of 5.3 years post-TPVR. CONCLUSIONS: TPVR in patients with d-TGA after ASO is feasible, but in this cohort, coronary compression or aortic root distortion precluded TPVR in one-third of patients. The rate of RVOT reintervention after TPVR was higher in this cohort of ASO patients that in prior studies.

Ventricular arrhythmias following balloon-expandable transcatheter pulmonary valve replacement in the native right ventricular outflow tract.

BACKGROUND: Ventricular arrhythmia incidence in children and adolescents undergoing transcatheter pulmonary valve replacement (TPVR) within the native right ventricular outflow tract (nRVOT) is unknown. We sought to describe the incidence, severity, and duration of ventricular arrhythmias and identify associated risk factors in this population. METHODS: This was a retrospective cohort study of 78 patients <21 years of age who underwent TPVR within the nRVOT. Patients were excluded for pre-existing ventricular arrhythmia or antiarrhythmic use. Study variables included surgical history, valve replacement indication, valve type/size, and ventricular arrhythmia. Univariable logistic regression models were used to evaluate factors associated with ventricular arrhythmias, followed by subset analyses. RESULTS: Nonsustained ventricular arrhythmia occurred in 26/78 patients (33.3%). The median age at the procedure was 10.3 years (interquartle range [IQR]: 6.5, 12.8). Compared with other nRVOT types, surgical repair with transannular patch was protective against ventricular arrhythmia incidence: odds ratio (OR): 0.35 (95% confidence interval [CI], 0.13-0.95). Patient weight, valve type/size, number of prestents, and degree of stent extension into the RVOT were not associated with ventricular arrhythmia occurrence. Beta blocker was started in 16/26 (61.5%) patients with ventricular arrhythmia. One additional patient was lost to follow-up. The median beta blocker duration was 46 days (IQR 42, 102). Beta blocker was discontinued in 10 patients by 8-week follow-up and in the remaining four by 9 months. CONCLUSIONS: Though common after balloon-expandable TPVR within the nRVOT, ventricular arrhythmias were benign and transient. Antiarrhythmic medications were successfully discontinued in the majority at 6- to 8-week follow-up, and in all patients by 20 months.

Over-expansion of right ventricle to pulmonary artery conduits during transcatheter pulmonary valve placement.

OBJECTIVES: To determine the safety and feasibility of over-expansion of right ventricle to pulmonary artery conduits during transcatheter pulmonary valve placement. BACKGROUND: Transcatheter pulmonary valve placement is an alternative to surgical pulmonary valve replacement. Traditionally, it was thought to be unsafe to expand a conduit to >110% of its original size. METHODS: This retrospective cohort study from two centers includes patients with right ventricle to pulmonary artery conduits with attempted transcatheter pulmonary valve placement from 2010 to 2017. Demographic, procedural, echocardiographic and follow-up data, and complications were evaluated in control and overdilation (to >110% original conduit size) groups. RESULTS: One hundred and seventy-two patients (51 overdilation and 121 control) had attempted transcatheter pulmonary valve placement (98% successful). The overdilation group was younger (11.2 versus 16.7 years, p < 0.001) with smaller conduits (15 versus 22 mm, p < 0.001); however, the final valve size was not significantly different (19.7 versus 20.2 mm, p = 0.2). Baseline peak echocardiographic gradient was no different (51.8 versus 55.6 mmHg, p = 0.3). Procedural complications were more frequent in overdilation (18%) than control (7%) groups (most successfully addressed during the procedure). One patient from each group required urgent surgical intervention, with no procedural mortality. Follow-up echocardiographic peak gradients were similar (24.1 versus 26 mmHg, p = 0.5). CONCLUSIONS: Over-expansion of right ventricle to pulmonary artery conduits during transcatheter pulmonary valve placement can be performed successfully. Procedural complications are more frequent with conduit overdilation, but there was no difference in the rate of life-threatening complications. There was no difference in valve function at most recent follow-up, and no difference in rate of reintervention. The long-term outcomes of transcatheter pulmonary valve placement with conduit over-expansion requires further study.

Echocardiographic Assessment of Melody Versus Sapien Valves Following Transcatheter Pulmonary Valve Replacement.

OBJECTIVES: The aim of this study was to compare the immediate and midterm echocardiographic performance of the Melody (Medtronic Inc) and Sapien (Edwards Lifesciences Inc) valves after transcatheter pulmonary valve replacement (TPVR) in native and conduit right ventricular outflow tracts (RVOTs). BACKGROUND: TPVR is now a common procedure, but limited data exist comparing postimplantation echocardiographic findings between Melody and Sapien valves. METHODS: This was a single-institution retrospective cohort study of all patients who underwent successful TPVR from 2011 to 2020. Patient demographics, procedural details, and immediate and midterm echocardiographic findings were collected and compared between valve types using the Wilcoxon rank sum, chi-square, or Fisher exact test as appropriate. Subgroups were analyzed individually and were adjusted for multiple comparisons using the Bonferroni method. RESULTS: A total of 328 patients underwent successful TPVR (Melody: n = 202, Sapien: n = 126). The groups had a similar baseline age, weight, and diagnosis. The most common indications for TPVR were pulmonary stenosis (32.2%) or mixed disease (46%) in the Melody group and pulmonary insufficiency in the Sapien group (52.4%) (P < 0.001). Sapien valves were more often placed in native RVOTs (43.7% vs 18.8%; P < 0.001). The discharge and follow-up mean and peak Doppler gradients were similar between the Melody and Sapien groups. Valves implanted in native RVOTs had significantly lower postimplantation gradients at each follow-up period. CONCLUSIONS: Echocardiographic performance after TPVR was generally acceptable and similar when comparing Melody and Sapien valves despite differences in the indication and anatomy in each group. The peak and mean gradients were lower in transcatheter valves implanted in native RVOTs compared with those implanted in conduits or bioprosthetic valves.

Short-Term Left Ventricular Reverse Remodeling after Transcatheter Aortic Valve Replacement in Children.

BACKGROUND: There are no published data on left ventricular (LV) reverse remodeling after transcatheter aortic valve replacement (TAVR) in children. The aim of this study was to assess changes in LV echocardiographic parameters 6 months after TAVR in children. METHODS: This single-center, retrospective study included all 22 patients (age < 21 years) who underwent TAVR. The median age was 14.7 years (interquartile range, 13.3-15.9 years), median weight was 57 kg (interquartile range, 46.0-66.3 kg), and 59% of patients were male. Demographics, type and duration of aortic valve dysfunction, symptom and treatment data, and preprocedural and 6-month follow-up echocardiographic data (LV volume, mass, end-diastolic dimension, end-systolic dimension, ejection fraction [EF], sphericity, and longitudinal strain) were collected. Failure to reverse remodel at 6 months was defined as meeting at least two of the following: Z score ≥ 2 that was unchanged or increased from baseline for LV volume, mass, end-diastolic dimension, or end-systolic dimension; abnormally high sphericity index that was unchanged or increased; and abnormally low EF or longitudinal strain. Median, interquartile range, and range are reported for continuous variables, and pre- and post-TAVR data were compared using the Wilcoxon signed rank test. RESULTS: Eight patients (36%) had isolated aortic stenosis, four (18%) had isolated regurgitation, and 10 had (46%) mixed disease. Twelve (55%) had symptoms and 20 (91%) had prior surgical or catheter valve interventions. The primary complication was left bundle branch block, occurring in four children (18%). At 6 months, LV volume, mass, end-diastolic dimension, end-systolic dimension, and sphericity index improved. EF and strain were normal at baseline and at follow-up. Of three patients who failed to reverse remodel, two had left bundle branch block. Of three patients with persistent symptoms, one had failure of reverse remodeling. CONCLUSIONS: Most pediatric patients had evidence of reverse LV remodeling 6 months after TAVR, suggesting a possible alternative to surgical aortic valve replacement in this population. Functional parameters (EF and strain) were normal at baseline and follow-up. Future studies are needed to determine optimal timing of TAVR and to explore the association of postprocedural left bundle branch block on failed reverse remodeling and outcomes in this population.

Transcatheter and Surgical Aortic Valve Implantation in Children, Adolescents, and Young Adults With Congenital Heart Disease.

Transcatheter aortic valve implantation (TAVI) is common in adults but rare in children and adolescents. Since 2014, our institution has incorporated a transcatheter approach as an option for aortic valve replacement in this population. The purpose of this study was to compare short-term outcomes of TAVI with surgical aortic valve replacement (SAVR). This single-center, retrospective study included patients aged 10 to 21 years who had a native SAVR or TAVI between January 2010 to April 2020. Comparative analysis of baseline characteristics and a composite outcome (stroke within 6 months, readmission within 30 days, death) between SAVR and TAVI were made using chi-square test or Wilcoxon rank sum test, as appropriate. Of the 77 patients who underwent native aortic valve implantation during the study period (60 SAVR, 17 TAVI), 46 were aged 10 to 21 years (30 SAVR, 16 TAVI). Median follow-up was 3.8 years (interquartile range 1.5 to 4.9) for the SAVR group and 1.5 years (interquartile range 1.1 to 1.2) for the TAVI group. There was no difference in the composite outcome between groups. Patients in the SAVR group were more likely to have undergone concomitant surgical intervention and have longer intensive care unit and hospital stays. In conclusion, our study suggests similar short-term outcomes between SAVR and TAVI in children and young adults aged 10 to 21 years. Longer-term studies are essential to understand the utility of TAVI and to better consider the option of a transcatheter approach as an alternative to SAVR in the pediatric population.

Natural history of Danon disease.

BACKGROUND: Danon disease is a rare but serious cardiac and skeletal myopathy leading to substantial morbidity and early mortality due to arrhythmia and cardiomyopathy. The X-linked nature of inheritance accounts for reported differences in phenotypic severity between men and women. The rarity of Danon disease has limited understanding of the complete phenotype. Clinical estimates of ages of disease onset and survival based on gender have not been published. METHODS AND RESULTS: We present data on 82 patients with Danon disease from 36 families, the largest series to date. Men were severely affected with cognitive disabilities (100%), hypertrophic cardiomyopathy (88%), and muscle weakness (80%). Men had a high morbidity and were unlikely to reach the age of 25 years without a cardiac transplantation. Women were less severely affected but reported higher than expected levels of cognitive (47%) and skeletal muscle complaints (50%) and manifesting an equal prevalence of dilated cardiomyopathy and hypertrophic cardiomyopathy. Combining our data with that of 63 other Danon disease case reports in the literature, the average ages of first symptom, cardiac transplantation, and death were 12.1, 17.9, and 19.0 years in men and 27.9, 33.7, and 34.6 years in women, respectively. CONCLUSION: These data more broadly illuminate the Danon disease phenotype and should prove useful to physicians working with and providing genetic counseling to families with Danon disease. Women with Danon disease present with clinical symptoms and events approximately 15 years after men and report a higher proportion of cognitive and skeletal muscle problems than previously recognized.

Functional performance and muscle strength phenotypes in men and women with Danon disease.

Danon disease is a rare X-linked myopathy that is characterized clinically by a triad of cardiomyopathy, skeletal myopathy, and cognitive impairment. The purpose of this investigation was to quantify functional performance, muscle weakness, and quadriceps activation in individuals with Danon disease as compared with healthy individuals. Four males (ages 10-34 years) and 4 females (ages 16-50 years), with the genetic markers of Danon disease, were compared with 8 healthy males (ages 22-34 years) and 8 healthy females (ages 23-41 years) and previously reported norms. Affected males and females had decreased functional performance, significant generalized muscle weakness, and decreased quadriceps strength and activation when compared with healthy individuals. Affected males had larger deficits in function, strength, and activation when compared with affected females. The results indicate that, although the presentation of Danon disease is variable and is typically only described in males, muscle weakness patterns exist in both affected males and females.

Blalock-Taussig shunt versus patent ductus arteriosus stent as first palliation for ductal-dependent pulmonary circulation lesions: A review of the literature.

BACKGROUND: Infants with ductal-dependent pulmonary blood flow (PBF) often undergo a palliative procedure to provide a stable source of PBF prior to definitive palliation or repair. In the current era, a surgical shunt or ductal stent is used to provide PBF. We aimed to review the current literature comparing ductal stents to surgical shunts. METHODS AND RESULTS: Four small, single-center studies and two larger multicenter studies were identified comparing ductal stent to surgical shunt. Combined, these studies showed ductal stent resulted in similar or improved pulmonary artery growth, fewer complications, shorter length of stay, less diuretic use, and improved survival compared to surgical shunt. Despite inherent minor variability among the studies, ductal stent appears to be associated with more frequent reinterventions. CONCLUSIONS: Surgical shunts remain essential to the care of these patients, but ductal stent is a reasonable alternative, and may provide some advantages in select patients with ductal-dependent PBF.

Exercise can prevent and reverse the severity of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common form of sudden death in young competitive athletes. However, exercise has also been shown to be beneficial in the setting of other cardiac diseases. We examined the ability of voluntary exercise to prevent or reverse the phenotypes of a murine model of HCM harboring a mutant myosin heavy chain (MyHC). No differences in voluntary cage wheel performance between nontransgenic (NTG) and HCM male mice were seen. Exercise prevented fibrosis, myocyte disarray, and induction of "hypertrophic" markers including NFAT activity when initiated before established HCM pathology. If initiated in older HCM animals with documented disease, exercise reversed myocyte disarray (but not fibrosis) and "hypertrophic" marker induction. In addition, exercise returned the increased levels of phosphorylated GSK-3beta to those of NTG and decreased levels of phosphorylated CREB in HCM mice to normal levels. Exercise in HCM mice also favorably impacted components of the apoptotic signaling pathway, including Bcl-2 (an inhibitor of apoptosis) and procaspase-9 (an effector of apoptosis) expression, and caspase-3 activity. Remarkably, there were no differences in mortality between exercised NTG and HCM mice. Thus, not only was exercise not harmful but also it was able to prevent and even reverse established cardiac disease phenotypes in this HCM model.

Resource Utilization for Initial Hospitalization in Pediatric Heart Transplantation in the United States.

Pediatric heart transplantation (HT) is resource intensive. Event-driven pediatric databases do not capture data on resource use. The objective of this study was to evaluate resource utilization and identify associated factors during initial hospitalization for pediatric HT. This multicenter retrospective cohort study utilized the Pediatric Health Information Systems database (43 children's hospitals in the United States) of children ≤19 years of age who underwent transplant between January 2007 and July 2013. Demographic variables including site, payer, distance and time to center, clinical pre- and post-transplant variables, mortality, cost, and charge were the data collected. Total length of stay (LOS) and charge for the initial hospitalization were used as surrogates for resource use. Charges were inflation adjusted to 2013 dollars. Of 1,629 subjects, 54% were male, and the median age at HT was 5 years (IQR [interquartile range] 0 to 13). The median total and intensive care unit LOS were 51 (IQR 23 to 98) and 23 (IQR 9 to 58) days, respectively. Total charge and cost for hospitalization were $852,713 ($464,900 to $1,609,300) and $383,600 ($214,900 to $681,000) respectively. Younger age, lower volume center, southern region, and co-morbidities before transplant were associated with higher resource use. In later years, charges increased despite shorter LOS. In conclusion, this large multicenter study provides novel insight into factors associated with resource use in pediatric patients having HT. Peritransplant morbidities are associated with increased cost and LOS. Reducing costs in line with LOS will improve health-care value. Regional and center volume differences need further investigation for optimizing value-based care and efficient use of scarce resources.

The role of MEKK1 in hypertrophic cardiomyopathy.

MEKK1 is a ubiquitously expressed mitogen activated protein kinase that is involved in tissue remodeling in a variety of settings including carotid artery blood flow cessation, wound healing, and breast adenocarcinoma intravasation. Here, we have tested the function of MEKK1 in genetic hypertrophic cardiomyopathy (HCM). MEKK1 was genetically deleted in C57Bl6/J mice expressing a mutant alpha-myosin heavy chain (HCM-MEKK1(-/-)). The absence of MEKK1 in HCM resulted in a more pronounced hypertrophy when compared to HCM mice with the MEKK1 gene intact without further increases in atrial natriuretic factor and beta-myosin heavy chain (MyHC) expression and fibrosis. Since MEKK1 is required for the induction of several tissue proteases, we tested the hypothesis that cardiac enlargement of HCM- MEKK1(-/-) mice was due to altered expression of urokinase-type plasminogen activator (uPA), JunB, matrix-metalloproteinase (MMP), and tissue inhibitors of MMPs (TIMPs). Because of its role in preventing apoptosis, we also tested the loss of MEKK1 on apoptotic mediators Bcl-2, cytochrome C, caspase-9, and caspase-3. uPA expression was decreased while JunB, MMP-9, caspase-9, and caspase-3 activities were elevated in HCM- MEKK1(-/-) hearts when compared to MEKK1(-/-), wild-type (WT), and HCM mice. Bcl-2 and Cyt C expression was elevated only in HCM mice. We conclude that the absence of MEKK1 induces a more pronounced cardiac hypertrophy to HCM through altered expression of proteases implicated in cardiac remodeling and increased apoptosis.