Patient-Specific Bicuspid Aortic Valve Biomechanics: A Magnetic Resonance Imaging Integrated Fluid-Structure Interaction Approach.

Congenital bicuspid aortic valve (BAV) consists of two fused cusps and represents a major risk factor for calcific valvular stenosis. Herein, a fully coupled fluid-structure interaction (FSI) BAV model was developed from patient-specific magnetic resonance imaging (MRI) and compared against in vivo 4-dimensional flow MRI (4D Flow). FSI simulation compared well with 4D Flow, confirming direction and magnitude of the flow jet impinging onto the aortic wall as well as location and extension of secondary flows and vortices developing at systole: the systolic flow jet originating from an elliptical 1.6 cm2 orifice reached a peak velocity of 252.2 cm/s, 0.6% lower than 4D Flow, progressively impinging on the ascending aorta convexity. The FSI model predicted a peak flow rate of 22.4 L/min, 6.7% higher than 4D Flow, and provided BAV leaflets mechanical and flow-induced shear stresses, not directly attainable from MRI. At systole, the ventricular side of the non-fused leaflet revealed the highest wall shear stress (WSS) average magnitude, up to 14.6 Pa along the free margin, with WSS progressively decreasing towards the belly. During diastole, the aortic side of the fused leaflet exhibited the highest diastolic maximum principal stress, up to 322 kPa within the attachment region. Systematic comparison with ground-truth non-invasive MRI can improve the computational model ability to reproduce native BAV hemodynamics and biomechanical response more realistically, and shed light on their role in BAV patients' risk for developing complications; this approach may further contribute to the validation of advanced FSI simulations designed to assess BAV biomechanics.

Right and left ventricle native T1 mapping in systolic phase in patients with congenital heart disease.

BACKGROUND: T1 mapping is emerging as a powerful tool in cardiac magnetic resonance (CMR) to evaluate diffuse fibrosis. However, right ventricular (RV) T1 mapping proves difficult due to the limited wall thickness in diastolic phase. Several studies focused on systolic T1 mapping, albeit only on the left ventricle (LV). PURPOSE: To estimate intra- and inter-observer variability of native T1 (nT1) mapping of the RV, and its correlations with biventricular and pulmonary function in patients with congenital heart disease (CHD). MATERIAL AND METHODS: In this retrospective, observational, cross-sectional study we evaluated 36 patients with CHD, having undergone CMR on a 1.5-T scanner. LV and RV functional evaluations were performed. A native modified look-locker inversion recovery short-axis sequence was acquired in the systolic phase. Intra- and inter-reader reproducibility were reported as complement to 100% of the ratio between coefficient of reproducibility and mean. Spearman ρ and Mann-Whitney U-test were used to compare distributions. RESULTS: Intra- and inter-reader reproducibility was 84% and 82%, respectively. Median nT1 was 1022 ms (interquartile range [IQR] 1108-972) for the RV and 947 ms (IQR 986-914) for the LV. Median RV-nT1 was 1016 ms (IQR 1090-1016) in patients with EDVI ≤100 mL/m2 and 1100 ms (IQR 1113-1100) in patients with EDVI >100 mL/m2 (P = 0.049). A significant negative correlation was found between RV ejection fraction and RV-nT1 (ρ = -0.284, P = 0.046). CONCLUSION: Systolic RV-nT1 showed a high reproducibility and a negative correlation with RV ejection fraction, potentially reflecting an adaptation of the RV myocardium to pulmonary valve/conduit (dys)-function.

Prediction of post-stenting biomechanics in coarcted aortas: A pilot finite element study.

Endovascular stenting has recently become a standard treatment for native coarctation of the aorta (CoA) in children and young adults, given the efficacy in relieving vessel obstruction with a low incidence of adverse events. Yet, despite the short-term success of the technique, late hypertension remains an endemic risk. To assess the impact of the percutaneous procedure on the aortic wall biomechanics, we designed a novel finite element (FE) protocol for the simulation of endovascular stenting in three patient-specific CoA anatomies, developing a remeshing procedure that allows for coping with different CoA severities. Our FE protocol was able to yield numerical results on stent distortions and stresses, as well as on changes in aortic wall stresses and distensibility. These results were consistent with intraprocedural in-vivo evidences and with previous findings from the literature, and they suggest that our numerical approach could be used to understand the role of patient specific anatomical features (CoA severity and arch type) on the post-stenting aortic biomechanics. If soundly validated on a vast cohort of patients, our approach could support patient selection for the procedure.

Predictors of index admission mortality and morbidity in contemporary esophageal atresia patients.

BACKGROUND/PURPOSE: The Spitz classification for esophageal atresia with/without tracheoesophageal fistula (EA/TEF) predicts mortality. This study evaluates the contemporary relevance of the Spitz classification and investigates predictors of morbidity. METHODS: EA/TEF patients born between 1995 and 2018 at two centers were retrospectively reviewed. Clinical variables including sex, prenatal diagnosis, birth weight, prematurity, major congenital heart disease (MCHD), and pre-operative mechanical ventilation (POMV) were collected. Index admission composite morbidity was considered positive if: length-of-stay >90th percentile (139 days), ventilation days >90th percentile (24 days), and/or gastrostomy was used for long-term feeding. Multivariable regression determined predictors of index admission mortality and composite morbidity. A composite morbidity predictive algorithm was created. ROC curves evaluated model discrimination. RESULTS: Of 253 patients, 13 (5.1%) experienced index admission mortality. Of the patients not suffering mortality, 74 (31.6%) experienced composite morbidity. Only MCHD predicted mortality (p = 0.001); birth weight did not (p = 0.173). There was no difference between the Spitz classification and MCHD alone in predicting mortality risk (p = 0.198); both demonstrated very good discrimination. Prenatal diagnosis, POMV, prematurity, and male sex predicted composite morbidity risk (p < 0.001; p = 0.008; p = 0.009; p = 0.05). An algorithm incorporating these predictors demonstrated good discrimination (AUC = 0.784; 95% CI: 0.724, 0.844). CONCLUSIONS: The Spitz classification maintains contemporary relevance for mortality risk, though birth weight can be de-emphasized. A new morbidity risk algorithm is proposed for early postnatal counseling. TYPE OF STUDY: Prognosis study. LEVEL OF EVIDENCE: Level IV.

4D Flow MRI hemodynamic benchmarking of surgical bioprosthetic valves.

PURPOSE: We exploited 4-dimensional flow magnetic resonance imaging (4D Flow), combined with a standardized in vitro setting, to establish a comprehensive benchmark for the systematic hemodynamic comparison of surgical aortic bioprosthetic valves (BPVs). MATERIALS AND METHODS: 4D Flow analysis was performed on two small sizes of three commercialized pericardial BPVs (Trifecta™ GT, Carpentier-Edwards PERIMOUNT Magna and Crown PRT®). Each BPV was tested over a clinically pertinent range of continuous flow rates within an in vitro MRI-compatible system, equipped with pressure transducers. In-house 4D Flow post-processing of the post-valvular velocity field included the quantification of BPV effective orifice area (EOA), transvalvular pressure gradients (TPG), kinetic energy and viscous energy dissipation. RESULTS: The 4D Flow technique effectively captured the 3-dimensional flow pattern of each device. Trifecta exhibited the lowest range of velocity and kinetic energy, maximized EOA (p < 0.0001) and minimized TPGs (p ≤ 0.015) if compared with Magna and Crown, these reporting minor EOA difference s (p ≥ 0.042) and similar TPGs (p ≥ 0.25). 4D Flow TPGs estimations strongly correlated against ground-truth data from pressure transducers; viscous energy dissipation proved to be inversely proportional to the fluid jet penetration. CONCLUSION: The proposed 4D Flow analysis pinpointed consistent hemodynamic differences among BPVs, highlighting the not negligible effect of device size on the fluidynamic outcomes. The efficacy of non-invasive 4D Flow MRI protocol could shed light on how standardize the comparison among devices in relation to their actual hemodynamic performances and improve current criteria for their selection.

3-Dimensional personalized planning for transcatheter pulmonary valve implantation in a dysfunctional right ventricular outflow tract.

BACKGROUND: Identification of adequate landing zone for transcatheter pulmonary valve implantation (TPVI) is crucial to successfully treat an aneurysmatic native right ventricle outflow tract (RVOT); three-dimensional (3D) patient-tailored digital and physical printed models are available but their actual strengths and weaknesses still not well documented. The aim of the study was to tackle TPVI planning in the dysfunctional and borderline RVOT exploiting both digital and physical printed 3D patient-specific models. METHODS: Electrocardiographically gated computed tomography (CT) angiography was segmented and anatomical RVOT geometrical changes dynamically tracked throughout the cardiac cycle using in-house processing. A compliant 3D-printed model was manufactured from the diastolic rest phase to test in vitro the catheter-based procedure feasibility; results were compared against CT-derived in vivo measurements and the actual catheterization outcome. RESULTS: CT-gated analysis successfully quantified in vivo RVOT dynamic changes corroborating the feasibility of non-conventional pulmonary jailing percutaneous intervention. Clinicians used the 3D-printed model to test the steps of the jailing procedure; yet, the deformable 3D model printed at diastole underestimated the final implant dimensions obtained during cardiac catheterization by the same operators. CONCLUSIONS: Multidisciplinary synergy between CT-gated analysis and pre-procedural tests on 3D-printed phantoms can help the interventional team to tackle complex TPVI procedures. To fully exploit 3D-printed models, adequate selection of the still frame to print and tuning of printing material properties is crucial and can be aided by 3D dynamic virtual models.

Surgical Atrioventricular Valve Replacement With Melody Valve in Infants and Children.

Background Pediatric patients with atrioventricular valve disease have limited options for prosthetic valve replacement in sizes <15 mm. Based on successful experience with the stented bovine jugular vein graft (Melody valve) in the right ventricular outflow tract, the prosthesis has been modified for surgical valve replacement in pediatric patients with atrioventricular dysfunction with the intention of subsequent valve expansion in the catheterization laboratory as the child grows. Methods and Results A multicenter, retrospective cohort study was performed among patients who underwent atrioventricular valve replacement with Melody valve at 17 participating sites from North America and Europe, including 68 patients with either mitral (n=59) or tricuspid (n=9) replacement at a median age of 8 months (range, 3 days to 13 years). The median size at implantation was 14 mm (range, 9-24 mm). Immediately postoperatively, the valve was competent with low gradients in all patients. Fifteen patients died; 3 patients underwent transplantation. Nineteen patients required reoperation for adverse outcomes, including valve explantation (n=16), left ventricular outflow tract obstruction (n=1), permanent pacemaker implantation (n=1), and paravalvular leak repair (n=1). Twenty-five patients underwent 41 episodes of catheter-based balloon expansion, exhibiting a significant decrease in median gradient ( P<0.001) with no significant increase in grade of regurgitation. Twelve months after implantation, cumulative incidence analysis indicated that 55% of the patients would be expected to be free from death, heart transplantation, structural valve deterioration, or valve replacement. Conclusions The Melody valve is a feasible option for surgical atrioventricular valve replacement in patients with hypoplastic annuli. The prosthesis shows acceptable short-term function and is amenable to catheter-based enlargement as the child grows. However, patients remain at risk for mortality and structural valve deterioration, despite adequate early valvular function. Device design and implantation techniques must be refined to reduce complications and extend durability. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02505074.

The NF-kB regulates the SHP-1 expression in monocytes in congestive heart failure.

It has been shown that functional recovery of patients with acute congestive heart failure (ACHF) after treatment with conventional drugs (CD) is mediated by suppression of inflammation in peripheral blood mononuclear cells. Here, we analyzed gene expression profiles of monocytes from symptomatic ACHF patients (NYHA Class III-IV) before and after pharmacological treatment with CD. The treatment was associated with selective down-regulation of "TNFR signaling" and pro-inflammatory mediators CCL5, MIP-1α receptor, CD14, ITGAM, and significant up-regulation of "TNFR signaling" as evidenced by increase in anti-inflammatory factors including NF-kBIA, TNFAIP3 and SHP-1. In monocyte TNF-alpha-stimulated there is a down-regulation of the phosphatase SHP-1 which induces a significant activation of TAK-1/IKK/NF-kB signaling. These findings suggest that the therapeutic impact of CD treatment in symptomatic ACHF includes negative regulation of the NF-kB signaling in monocytes and the improvement of the SHP-1 activity.

Diabetic human adipose tissue-derived mesenchymal stem cells fail to differentiate in functional adipocytes.

Adipose tissue dysfunction represents a hallmark of diabetic patients and is a consequence of the altered homeostasis of this tissue. Mesenchymal stem cells (MSCs) and their differentiation into adipocytes contribute significantly in maintaining the mass and function of adult adipose tissue. The aim of this study was to evaluate the differentiation of MSCs from patients suffering type 2 diabetes (dASC) and how such process results in hyperplasia or rather a stop of adipocyte turnover resulting in hypertrophy of mature adipocytes. Our results showed that gene profile of all adipogenic markers is not expressed in diabetic cells after differentiation indicating that diabetic cells fail to differentiate into adipocytes. Interestingly, delta like 1, peroxisome proliferator-activated receptor alpha, and interleukin 1ß were upregulated whereas Sirtuin 1 and insulin receptor substrate 1 gene expression were found downregulated in dASC compared to cells obtained from healthy subjects. Taken together our data indicate that dASC lose their ability to differentiate into mature and functional adipocytes. In conclusion, our in vitro study is the first to suggest that diabetic patients might develop obesity through a hypertrophy of existing mature adipocytes due to failure turnover of adipose tissue. Impact statement In the present manuscript, we evaluated the differentiative potential of mesenchymal stem cells (MSCs) in adipocytes obtained from healthy and diabetic patients. This finding could be of great potential interest for the field of obesity in order to exploit such results to further understand the pathophysiological processes underlying metabolic syndrome. In particular, inflammation in diabetic patients causes a dysfunction in MSCs differentiation and a decrease in adipocytes turnover leading to insulin resistance.

Surgery for supraventricular tachycardia and congenital heart defects: long-term efficacy of the combined approach in adult patients.

AIMS: Supraventricular arrhythmias are a major cause of morbidity and mortality in adult patients with congenital heart disease (CHD). Intraoperative ablation offers an alternative for patients who failed ablation procedures or are requiring concomitant surgical intervention. We present our long-term results with the surgical treatment of arrhythmias in adults with CHD (ACHD) undergoing elective cardiac surgery and the clinical predictors for arrhythmia recurrence. METHODS AND RESULTS: Between 2002 and 2013, 80 consecutive patients with CHD, mean age of 39 years, underwent intraoperative ablation with monopolar irrigated radiofrequency during cardiac surgery procedures. Significant clinical predictors of arrhythmia recurrence were determined by univariate analysis. We performed 47 right-sided Maze procedures, and 33 Cox-Maze III procedures. In 75 survivors, the ablation was effective immediately. Over an average follow-up period of 72 months (12-155 months), arrhythmias recurred in nine (20%) patients after right-sided Maze, and in six (19%) patients after Cox-Maze III. Eleven patients were controlled with medical therapy, three underwent catheter ablation of the arrhythmia, and one required a permanent pacemaker. Preoperative arrhythmia length ≥3 years (P ≤ 0.001), tetralogy of Fallot (P ≤ 0.006), and preoperative atrial fibrillation (P ≤ 0.016) were associated with recurrence arrhythmia. Conversely, NYHA class <3 (P ≤ 0.047) was associated with a lower risk of recurrence. CONCLUSION: Surgical treatment of unresponsive supraventricular arrhythmia during concomitant cardiac surgery in ACHD is a safe and effective procedure. Freedom from arrhythmias recurrence is 75% after 6 years of follow-up. Long-term recurrence of arrhythmia in these patients seems to be strongly correlated to preoperative arrhythmia duration.

Aortitis.

Aortitis encompasses all conditions, infectious or non-infectious, leading to different types of inflammation of the aortic wall. The clinical manifestations are usually nonspecific, as are laboratory findings, and sometimes may mimic other diseases. Imaging modalities can help in the assessment of these patients and are often required for making the final diagnosis. It is extremely important to establish an early diagnosis in order to treat timely potentially life-threatening conditions. Anti-inflammatory drugs, antibiotics, sometimes in combination with surgical or endovascular therapies, are proposed according to etiology and disease severity. This review focuses on the classification, epidemiology, diagnostic approach, and management of aortitis with which physicians should be familiar.

Multimodality cardiac imaging at IRCCS Policlinico San Donato: a new interdisciplinary vision.

Multimodality imaging is the efficient integration of various methods of cardiovascular imaging to improve the ability to diagnose, guide therapy, or predict outcome. This approach implies both the availability of different technologies in a single unit and the presence of dedicated staff with cardiologic and radiologic background and certified competence in more than one imaging technique. Interaction with clinical practice and existence of research programmes and educational activities are pivotal for the success of this model. The aim of this paper is to describe the multimodality cardiac imaging programme recently started at San Donato Hospital.

Predictors of Ominous Outcome in Infants who Undergo Cardiac Surgery and Cardiopulmonary By-Pass: S100B Protein.

S100B protein has been recently proposed as a consolidated marker of brain damage and death in adult, children and newborn patients. The present study evaluates whether the longitudinal measurement of S100B at different perioperative time-points may be a useful tool to identify the occurrence of perioperative early death in congenital heart disease (CHD) newborns. We conducted a case-control study in 88 CHD infants, without pre-existing neurological disorders or other co-morbidities, of whom 22 were complicated by perioperative death in the first week from surgery. Control group was composed by 66 uncomplicated CHD infants matched for age at surgical procedure. Blood samples were drawn at five predetermined timepoints before during and after surgery. In all CHD children, S100B levels showed a pattern characterized by a significant increase in protein's concentration from hospital admission up to 24-h after procedure reaching their maximum peak (P<0.01) during cardiopulmonary by-pass and at the end of the surgical procedure. Moreover, S100B concentrations in CHD death group were significantly higher (P<0.01) than controls at all monitoring time-points. The ROC curve analysis showed that S100B measured before surgical procedure was the best predictor of perioperative death, among a series of clinical and laboratory parameters, reaching at a cut-off of 0.1 µg/L a sensitivity of 100% and a specificity of 63.7%. The present data suggest that in CHD infants biochemical monitoring in the perioperative period is becoming possible and S100B can be included among a series of parameters for adverse outcome prediction.

Echocardiographic assessment after surgical repair of tetralogy of fallot.

Surgical correction of tetralogy of Fallot is still one of the most frequently performed intervention in pediatric cardiac surgery, and in many cases, it is far from being a complete and definitive correction. It is rather an excellent palliation that solves the problem of cyanosis, but predisposes the patients to medical and surgical complications during follow-up. The decision-making process regarding the treatment of late sequel is among the most discussed topics in adult congenital cardiology. In post-operative Fallot patients, echocardiography is used as the first method of diagnostic imaging and currently allows both a qualitative observation of the anatomical alterations and a detailed quantification of right ventricular volumes and function, of the right ventricular outflow tract, and of the pulmonary valve and pulmonary arteries. The literature introduced many quantitative echocardiographic criteria useful for the understanding of the pathophysiological mechanisms involving the right ventricle and those have made much more objective any decision-making processes.

Biochemical Markers for Brain Injury Monitoring in Children with or without Congenital Heart Diseases.

Perinatal asphyxia (PA) still constitutes a common complication involving a large number of infants with or without congenital heart diseases (CHD). PA affects 0.2-0.6% of full-term neonates, 20% of which suffer mortal hypoxic-ischemic encephalopathy, and among survivors 25% exhibit permanent consequences at neuropsychological level. Each year, about one third of 1000 live births underwent to surgical intervention in early infancy and/or are at risk for ominous outcome. Advances in brain monitoring, in anesthetic and cardiothoracic surgical techniques, including selective or total body cooling, cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest, have essentially reduced mortality expanding the possibility to address functional neurologic and cardiac outcomes in long-term survivors. However, open-heart surgery constitutes a time-frame of planned ischemia-reperfusion injury, which is a price to pay in the treatment or palliation of CHD. Infants who underwent heart surgery and non-CHD infants complicated by PA share similarities in their neurodevelopmental profile and a common form of brain damage due to hypoxic-ischemic injury. The purpose of the present review was to evaluate different mechanisms implicated in brain injury following CPB and PA and how it is possible to monitor such injury by means of available biomarkers (S100B protein, Activin A, Adrenomedullin).

Evaluation of right ventricular function in adults with congenital heart defects.

The right ventricle (RV) is of lesser importance in acquired heart disease, but its role is of increasing importance in congenital heart disease (CHD). Despite major progress being made, precise measurements of the RV are challenging because of its peculiar anatomical structure that is not adaptable to any planar geometrical assumption. This is particularly true in adult patients with CHD where the RV shape eludes any standardization, it may assume various morphologies, and its modality of contraction depends on previous surgical treatment and/or pathophysiological conditions. However, reliable and repeatable quantification of RV dimensions and function for these patients are essential to provide appropriate timing for intervention to optimize outcomes. In this population, echocardiographic evaluation should not be limited to an observational and subjective functional assessment of the RV but must provide quantitative values repeatable and clinically reliable to help the decision-making process. The aim of this review was to discuss the echocardiographic approach to the RV in adult patients with CHD in general and in specific cases of pressure or volume overload.

A roadmap to investigate the genetic basis of bicuspid aortic valve and its complications: insights from the International BAVCon (Bicuspid Aortic Valve Consortium).

Bicuspid aortic valve (BAV) is the most common adult congenital heart defect and is found in 0.5% to 2.0% of the general population. The term "BAV" refers to a heterogeneous group of disorders characterized by diverse aortic valve malformations with associated aortopathy, congenital heart defects, and genetic syndromes. Even after decades of investigation, the genetic determinants of BAV and its complications remain largely undefined. Just as BAV phenotypes are highly variable, the genetic etiologies of BAV are equally diverse and vary from complex inheritance in families to sporadic cases without any evidence of inheritance. In this paper, the authors discuss current concepts in BAV genetics and propose a roadmap for unraveling unanswered questions about BAV through the integrated analysis of genetic and clinical data.

Normal values of aortic root dimensions in healthy adults.

The reported ranges of aortic root (AR) diameters are limited by small sample size, different measurement sites, and heterogeneous cohorts. The aim of this study was to explore the full spectrum of AR diameters by 2-dimensional transthoracic color Doppler echocardiography (TTE) in a large cohort of healthy adults. From June 2007 to December 2013, a total of 1,043 Caucasian healthy volunteers (mean age 44.7 ± 15.9 years, range 16 to 92 years, 503 men [48%]) underwent comprehensive TTE. TTE measurements of the AR were made at end-diastole in parasternal long-axis views at 4 levels: (1) annulus, (2) sinuses of Valsalva, (3) sinotubular junction, and (4) proximal ascending aorta. The absolute aortic diameters were significantly greater in men than in women at all levels, whereas body surface area-indexed aortic diameters were greater in women (p = 0.0001). No significant gender differences were registered for sinuses of Valsalva and sinotubular junction to annulus diameter ratios (p = 0.9), whereas ascending aorta to annulus diameter ratio was higher in women (p = 0.0001). There was a straight correlation between aortic diameters (absolute and indexed values), their ratios, and age in both genders (p = 0.0001). In conclusion, we provide the full range of AR diameters by TTE. Knowledge of upper physiological limits of aortic dimensions is mandatory to detect aorta dilatation, follow up the disease over time, and plan appropriate therapeutic interventions.