Valvular heart disease in congenital heart disease: a narrative review

Role of Gut Microbial Metabolites in Cardiovascular Diseases-Current Insights and the Road Ahead

Cardiovascular diseases (CVDs) are the leading cause of premature morbidity and mortality globally. The identification of novel risk factors contributing to CVD onset and progression has enabled an improved understanding of CVD pathophysiology. In addition to the conventional risk factors like high blood pressure, diabetes, obesity and smoking, the role of gut microbiome and intestinal microbe-derived metabolites in maintaining cardiovascular health has gained recent attention in the field of CVD pathophysiology. The human gastrointestinal tract caters to a highly diverse spectrum of microbes recognized as the gut microbiota, which are central to several physiologically significant cascades such as metabolism, nutrient absorption, and energy balance. The manipulation of the gut microbial subtleties potentially contributes to CVD, inflammation, neurodegeneration, obesity, and diabetic onset. The existing paradigm of studies suggests that the disruption of the gut microbial dynamics contributes towards CVD incidence. However, the exact mechanistic understanding of such a correlation from a signaling perspective remains elusive. This review has focused upon an in-depth characterization of gut microbial metabolites and their role in varied pathophysiological conditions, and highlights the potential molecular and signaling mechanisms governing the gut microbial metabolites in CVDs. In addition, it summarizes the existing courses of therapy in modulating the gut microbiome and its metabolites, limitations and scientific gaps in our current understanding, as well as future directions of studies involving the modulation of the gut microbiome and its metabolites, which can be undertaken to develop CVD-associated treatment options. Clarity in the understanding of the molecular interaction(s) and associations governing the gut microbiome and CVD shall potentially enable the development of novel druggable targets to ameliorate CVD in the years to come.

Comparison of dimensions and functional features of mitral and tricuspid annuli in the same healthy adults: insights from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study

Background

Evaluation of mitral (MA) and tricuspid annuli (TA) in the same healthy subject in a non-invasive way in real-life clinical settings makes an opportunity to compare their dimensions and derived functional properties. The purpose of the present cohort study was to investigate whether there are any differences in the three-dimensional speckle-tracking echocardiography- (3DSTE-) measured size and derived functional characteristics of the MA and TA in the same healthy adults.

Methods

The study comprised 248 healthy adults, in which 3DSTE was performed to determine MA and TA dimensions and functional properties. Due to insufficient image quality, 89 cases were excluded, therefore the remaining population consisted of 159 subjects (age: 35.6±12.9 years, 76 males). Subjects were enrolled on a voluntary basis consecutively between January 2011 and November 2017 in the outpatient clinic of the tertiary cardiology center at the Department of Medicine, University of Szeged, Hungary. Data were analyzed by Student's t-test, analysis of variance (ANOVA) test, Fischer's exact test, Pearsons' correlations, interclass correlations and Bland-Altman tests.

Results

Same-side MA/TA end-diastolic annular dilation is associated with simultaneous MA/TA end-systolic dilation and vice versa. MA dilation in end-diastole and end-systole results in MA functional improvement/deterioration. Dilation of end-diastolic TA dimensions does not obviously entail differences in TA function. However, similar to MA, more dilated TA in end-systole is associated with impaired TA function. Dilated MA dimensions (end-diastolic MA area: 4.31±0.62 vs. 10.89±1.18 cm2, P<0.05) are not obviously associated with dilated end-diastolic TA dimensions (area: 7.05±1.42 vs. 7.81±1.48 cm2, P=ns) and functional improvement/impairment (fractional area change: 27.5%±10.8% vs. 25.2%±10.6%, P=ns).

Conclusions

Dilation of MA and TA is associated with different contralateral responses in morphology and function.

APOE-NOTCH axis governs elastogenesis during human cardiac valve remodeling

Valve remodeling is a process involving extracellular matrix organization and elongation of valve leaflets. Here, through single-cell RNA sequencing of human fetal valves, we identified an elastin-producing valve interstitial cell (VIC) subtype (apolipoprotein E (APOE)+, elastin-VICs) spatially located underneath valve endothelial cells (VECs) sensing unidirectional flow. APOE knockdown in fetal VICs resulted in profound elastogenesis defects. In valves with pulmonary stenosis (PS), we observed elastin fragmentation and decreased expression of APOE along with other genes regulating elastogenesis. Cell-cell interaction analysis revealed that jagged 1 (JAG1) from unidirectional VECs activates elastogenesis in elastin-VICs through NOTCH2. Similar observations were made in VICs cocultured with VECs under unidirectional flow. Notably, a drastic reduction of JAG1-NOTCH2 was also observed in PS valves. Lastly, we found that APOE controls JAG1-induced NOTCH activation and elastogenesis in VICs through the extracellular signal-regulated kinase pathway. Our study suggests important roles of both APOE and NOTCH in regulating elastogenesis during human valve remodeling.

Cardiac Computed Tomography in Congenital Heart Disease

Computed tomography (CT) has emerged as a leading imaging modality in the evaluation of congenital heart disease (CHD). With ever-faster acquisition speed, decreasing radiation exposure, impeccable anatomic detail, optional functional data, and numerous post-processing tools, CT offers broad utility in CHD diagnosis, preoperative planning, and postoperative assessment. In this article, the far-reaching role of CT in CHD is reviewed, focusing on technical imaging considerations and key clinical applications.

Caring for the Critically Ill Adult Congenital Heart Disease Patient

PURPOSE OF REVIEW

This review aims to discuss the unique challenges that adult congenital heart disease (ACHD) patients present in the intensive care unit.

RECENT FINDINGS

Recent studies suggest that ACHD patients make up an increasing number of ICU admissions, and that their care greatly improves in centers with specialized ACHD care. Common reasons for admission include arrhythmia, hemorrhage, heart failure, and pulmonary disease. It is critical that the modern intensivist understand not only the congenital anatomy and subsequent repairs an ACHD patient has undergone, but also how that anatomy can predispose the patient to critical illness. Additionally, intensivists should rely on a multidisciplinary team, which includes an ACHD specialist, in the care of these patients.

Feeder-free generation and characterization of endocardial and cardiac valve cells from human pluripotent stem cells

Valvular heart disease presents a significant health burden, yet advancements in valve biology and therapeutics have been hindered by the lack of accessibility to human valve cells. In this study, we have developed a scalable and feeder-free method to differentiate human induced pluripotent stem cells (iPSCs) into endocardial cells, which are transcriptionally and phenotypically distinct from vascular endothelial cells. These endocardial cells can be challenged to undergo endothelial-to-mesenchymal transition (EndMT), after which two distinct populations emerge-one population undergoes EndMT to become valvular interstitial cells (VICs), while the other population reinforces their endothelial identity to become valvular endothelial cells (VECs). We then characterized these populations through bulk RNA-seq transcriptome analyses and compared our VIC and VEC populations to pseudobulk data generated from normal valve tissue of a 15-week-old human fetus. By increasing the accessibility to these cell populations, we aim to accelerate discoveries for cardiac valve biology and disease.

The Genetics of Canine Pulmonary Valve Stenosis

There have been recent advancements in understanding the genetic contribution to pulmonary valve stenosis (PS) in brachycephalic breeds such as the French Bulldog and Bulldog. The associated genes are transcriptions factors involved in cardiac development, which is comparable to the genes that cause PS in humans. However, validation studies and functional follow up is necessary before this information can be used for screening purposes.

Trileaflet Semilunar Valve Reconstruction: Acute Porcine in Vivo Evaluation

Objective: The surgical treatment of malformed semilunar valves in congenital heart defects is challenging in terms of providing both longevity and the potential to grow with the recipient. We investigated a new surgical technique "Trileaflet Semilunar Valve Reconstruction" in an acute porcine model, a technique with geometrical properties that could remain sufficient and allow for some growth with the child. Methods: An acute 60-kg porcine model was used. With echocardiography, baseline pulmonary valvular geometry and hemodynamics were investigated. On cardiopulmonary bypass, the pulmonary leaflets were explanted, and the Trileaflet Semilunar Valve Reconstruction was performed with customized homograft-treated pericardial neo-leaflets. Off bypass, hemodynamics was reassessed. Results: Twelve animals were investigated. The neo-valves were found sufficient in ten animals and with minimal regurgitation in two animals. The neo-valve had a peak gradient of 3 ± 2 mm Hg with a peak velocity of 0.8 ± 0.2 m/s. The coaptation in the neo-valve had a mean increase of 4 ± 3 mm, P < .001. The neo-valve had a windmill shape in the echocardiographic short-axis view, and the neo-leaflets billowed at the annular plane in the long-axis view. Conclusions: In this acute porcine model, the neo-valve had no clinically significant regurgitation or stenosis. The neo-valve had an increased coaptation, a windmill shape, and leaflets that billowed at the annular plane. These geometric findings may allow for sustained sufficiency as the annular and pulmonary artery dimension increase with the child's growth. Further long-term studies should be performed to evaluate the efficacy and the growth potential.

Morbidity and Mortality of Heterotopic Partial Heart Transplantation in Rodent Models

Unrepairable congenital heart valve disease is an unsolved problem in pediatric cardiac surgery because there are no growing heart valve implants. Partial heart transplantation is a new type of transplant that aims to solve this problem. In order to study the unique transplant biology of partial heart transplantation, animal models are necessary. This study aimed to assess the morbidity and mortality of heterotopic partial heart transplantation in rodent models. This study assessed two models. The first model involved transplanting heart valves from donor animals into the abdominal aortic position in the recipient animals. The second model involved transplanting heart valve leaflets into the renal subcapsular position of the recipient animals. A total of 33 animals underwent heterotopic partial heart transplantation in the abdominal aortic position. The results of this model found a 60.61% (n = 20/33) intraoperative mortality rate and a 39.39% (n = 13/33) perioperative mortality rate. Intraoperative mortality was due to vascular complications from the procedure, and perioperative mortality was due to graft thrombosis. A total of 33 animals underwent heterotopic partial heart transplantation in the renal subcapsular position. The results of this model found a 3.03% (n = 1/33) intraoperative mortality rate, and the remaining 96.97% survived (n = 32/33). We conclude that the renal subcapsular model has a lower mortality rate and is technically more accessible than the abdominal aortic model. While the heterotopic transplantation of valves into the abdominal aortic position had significant morbidity and mortality in the rodent model, the renal subcapsular model provided evidence for successful heterotopic transplantation.

Insights and perspectives into clinical biomarker discovery in pediatric heart failure and congenital heart disease-a narrative review

Background and Objective

Heart failure (HF) in the pediatric population is a multi-factorial process with a wide spectrum of etiologies and clinical manifestations, that are distinct from the adult HF population, with congenital heart disease (CHD) as the most common cause. CHD has high morbidity/mortality with nearly 60% developing HF during the first 12 months of life. Hence, early discovery and diagnosis of CHD in neonates is pivotal. Plasma B-type natriuretic peptide (BNP) is an increasingly popular clinical marker in pediatric HF, however, in contrast to adult HF, it is not yet included in pediatric HF guidelines and there is no standardized reference cut-off value. We explore the current trends and prospects of biomarkers in pediatric HF, including CHD that can aid in diagnosis and management.

Methods

As a narrative review, we will analyze biomarkers with respect to diagnosis and monitoring in specific anatomical types of CHD in the pediatric population considering all English PubMed publications till June 2022.

Key Content and Findings

We present a concise description of our own experience in applying plasma BNP as a clinical biomarker in pediatric HF and CHD (tetralogy of fallot vs. ventricular septal defect) in the context of surgical correction, as well as untargeted metabolomics analyses. In the current age of Information Technology and large data sets we also explored new biomarker discovery using Text Mining of 33M manuscripts currently on PubMed.

Conclusions

(Multi) Omics studies from patient samples as well as Data Mining can be considered for the discovery of potential pediatric HF biomarkers useful in clinical care. Future research should focus on validation and defining evidence-based value limits and reference ranges for specific indications using the most up-to-date assays in parallel to commonly used studies.

Transcatheter Interventions for Atrioventricular Dysfunction in Patients with Adult Congenital Heart Disease: An International Case Series

INTRODUCTION

A substantial proportion of patients with adult congenital heart disease (ACHD) suffer from worsening valvular dysfunction in adulthood. Transcatheter valve interventions can offer a therapeutic alternative to surgery for those at high surgical risk. There is emerging but limited data on transcatheter interventions for atrioventricular (AV) valve dysfunction in patients with ACHD.

METHODS

We compiled an international collaborative multi-center registry focusing on adult patients with congenital heart disease undergoing transcatheter AV valve interventions (repair or replacement). Included were patients from three international centers who underwent procedures between 2016 and 2022. Demographic, clinical, and procedural data were compiled.

RESULTS

Nine patients with ACHD underwent AV valve interventions. The median age was 48 years (IQR (37; 56), 55% women). At baseline, seven patients (78%) were in NYHA functional class III and two (22%) were in NYHA functional class II. The diagnosis of ACHD varied. Three valve interventions were performed on the subpulmonary AV valve and six on the systemic AV valve. The primary valvular pathology was regurgitation (six patients, 78%). Five procedures were valve-in-valve interventions, and four procedures were transcatheter edge-to-edge repair procedures. There were no major complications or peri-procedural complications or peri-procedural mortality. One patient developed a suspected non-obstructive thrombus on the valve that was medically treated. One patient did not improve clinically following the procedure and underwent a heart transplant, one patient died 6 months following the procedure due to a cardiovascular implantable electronic device infection. At one year, six patients were in NYHA functional class I, and one patient was in NYHA functional class III. In conclusion, transcatheter AV heart valve interventions are feasible and safe procedures in carefully selected ACHD patients. These procedures can offer an effective treatment option in these younger patients with high surgical risk.

The Adult Congenital Heart Disease Anatomic and Physiological Classification: Associations with Clinical Outcomes in Patients with Atrial Arrhythmias

The implications of the adult congenital heart disease anatomic and physiological classification (AP-ACHD) for risk assessment have not been adequately studied. A retrospective cohort study was conducted using data from an ongoing national, multicentre registry of patients with ACHD and atrial arrhythmias (AA) receiving apixaban (PROTECT-AR study, NCT03854149). At enrollment, patients were stratified according to Anatomic class (AnatC, range I to III) and physiological stage (PhyS, range B to D). A follow-up was conducted between May 2019 and September 2021. The primary outcome was a composite of death from any cause, any major thromboembolic event, major or clinically relevant non-major bleeding, or hospitalization. Cox proportional-hazards regression modeling was used to evaluate the risks for the outcome among AP-ACHD classes. Over a median 20-month follow-up period, 47 of 157 (29.9%) ACHD patients with AA experienced the composite outcome. Adjusted hazard ratios (aHR) with 95% confidence intervals (CI) for the outcome in PhyS C and PhyS D were 1.79 (95% CI 0.69 to 4.67) and 8.15 (95% CI 1.52 to 43.59), respectively, as compared with PhyS B. The corresponding aHRs in AnatC II and AnatC III were 1.12 (95% CI 0.37 to 3.41) and 1.06 (95% CI 0.24 to 4.63), respectively, as compared with AnatC I. In conclusion, the PhyS component of the AP-ACHD classification was an independent predictor of net adverse clinical events among ACHD patients with AA.