Valvular Calcification Research Articles

Assessment of Paravalvular Leak Severity and Thrombogenic Potential in Transcatheter Bicuspid Aortic Valve Replacements Using Patient-Specific Computational Modeling.

Bicuspid aortic valve (BAV), the most common congenital valvular abnormality, generates asymmetric flow patterns and increased stresses on the leaflets that expedite valvular calcification and structural degeneration. Recently adapted for use in BAV patients, TAVR demonstrates promising performance, but post-TAVR complications tend to get exacerbated due to BAV anatomical complexities. Utilizing patient-specific computational modeling, we address some of these complications. The degree and location of post-TAVR PVL was assessed, and the risk of flow-induced thrombogenicity was analyzed in 3 BAV patients - using older generation TAVR devices that were implanted in these patients, and compared them to the performance of the newest generation TAVR devices using in silico patient models. Significant decrease in PVL and thrombogenic potential was observed after implantation of the newest generation device. The current work demonstrates the potential of using simulations in pre-procedural planning to assess post-TAVR complications, and compare the performance of different devices to achieve better clinical outcomes. Patient-specific computational framework to assess post-transcatheter bicuspid aortic valve replacement paravalvular leakage and flow-induced thrombogenic complications and compare device performances.

Abstract 10223: Tissue-Entrapped Extracellular Vesicles Modulate Divergent Mechanisms of Cardiovascular Calcification

Introduction: Fewer than 50% of patients develop vascular and valvular calcification, implying differential pathogenesis. Tissue-entrapped extracellular vesicles (EVs) are implicated in mineralization but their contents and functions are unstudied. We investigated entrapped EV cargoes in human cardiovascular disease. Methods: Human carotid endarterectomy specimens and stenotic aortic valves were obtained from 53 patients. Disease stage-specific proteomics was performed on whole tissue (non-diseased/fibrotic/calcified areas). Tissue EVs were enriched by gradient fractionation then underwent proteomics and miRNA-seq. miR targets were predicted by TargetScan, pathway analyses utilized BioCarta/KEGG/Reactome, and protein-protein interaction networks employed STRING. Results: Disease progression drove significant convergence (p<0.0001) of atherosclerotic plaque and valve proteomes (2,318 proteins). 548 and 158 proteins were exclusively altered (q<0.05) by disease in plaques or valves, respectively. Vesicular GO terms increased 2.2x (p<0.01) amongst proteins altered by disease in both tissues (202). Proteomics found 24 EV markers in the low-density fractions of plaques and valves, confirmed by electron microscopy and nanoparticle tracking. EV omics quantified 1,104 proteins and 123 miR cargoes. Networks of proteins and miR targets shared by plaque and valve EVs revealed common regulation of Rho GTPase and MAPK signaling. 179 proteins and 5 miRs were altered between plaque and valve EVs (q<0.05); multi-omics integration found that EVs modulated cellular contraction and p53-mediated transcriptional regulation in plaques and valves, respectively. Conclusions: This first comparative proteomics study of human valves and arteries finds shared EV functionality in both diseases. Using novel means to examine tissue EV molecular cargoes, we also reveal critical divergent tissue-specific roles for EVs in mediating cardiovascular disease.

Abstract 13243: Integrin Linked Kinase Expression in Human Valvular Endothelial Cells Plays a Protective Role in Calcific Aortic Valve Disease

Introduction: Calcific aortic valve disease (CAVD) is the most common valvular heart disease in the aging population. CAVD is a highly active ossification process originated in valvular interstitial cells which differentiate towards an osteoblastic phenotype. However, the role of valvular endothelial cells in CAVD has not been fully explored. We previously demonstrated that ILK expression in vascular endothelium plays an essential cardioprotective role. Hypothesis: Endothelial ILK plays a protective role in human valvular endothelial cells osteogenesis. Methods and Results: Human aortic valves were obtained from 52 patients with calcific aortic stenosis compared with 16 non-calcified aortic valves and ILK levels were analyzed. Our study showed a significant relationship between the degree of AV calcification and decreased ILK expression detected by IHQ and qPCR (p< 0,013). Moreover, decreased ILK expression correlated with BMP2 and Runx2, two markers of valvular calcification (p<0.01). Human valvular endothelial cells (hVECs) isolated from non-calcified controls display the ability to calcify when cultured in pro-calcifiying conditions and ILK levels were unaffected by the pro-calcifiying conditions. However, silencing ILK expression in hVECs resulted in decreased NO production, increased expression of calcific disease markers Runx2, BMP2, and osteopontin. ILK silencing in hVECs induced calcium deposition, determined by alizarin red staining, when cultured in pro-calcifiying conditions. Thus, our results suggest that decreased ILK expression could promote endothelial to osteogenic phenotype transition. Restoring nitric oxide levels by DETA-NONOate treatment in ILK silenced hVEC was able to reverse those effects partially. Conclusions: Collectively, our results point to a crucial role of ILK in maintaining human valve endothelial cell function preventing valvular calcification.

Abstract 10885: Decreased Hydraulic Force Contributes to Diastolic Dysfunction and Associates with Survival Beyond Conventional Measures of Diastolic Dysfunction

Introduction: Decreased hydraulic force has recently been identified as a mechanism contributing to left ventricular (LV) diastolic dysfunction and heart failure with preserved ejection fraction (HFpEF). However, it is unclear if hydraulic forces are independently associated with survival. Hypothesis: Decreased diastolic hydraulic force, estimated as the atrioventricular area difference (AVAD), is associated with survival independent of conventional diastolic dysfunction measures. Methods: Patients (n=37947, median [interquartile range] 4.9 [2.9-8.0] years follow-up, 6103 events) were selected from the National Echo Database Australia based on the presence of relevant transthoracic echocardiographic measures, LV ejection fraction (LVEF) ≥ 50%, heart rate 50-100 beats/minute, the absence of moderate or severe valvular disease, pericardial disease or mitral annular calcification, and no prior cardiac surgery. AVAD was calculated as the cross-sectional area difference between the LV and left atrium (LA) using circular approximation of LV end-diastolic diameter and LA end-systolic diameter. LV diastolic dysfunction grading was performed according to 2016 guidelines. Results: In multivariable linear regression, AVAD was weakly associated with E/e’, e’, peak tricuspid regurgitation velocity, and LVEF (global adjusted R2=0.11, p<0.001), but not associated with left atrial volume index (p=0.83). In multivariable Cox regression, there was an association with survival for both AVAD (chi-square 279, hazard ratio (HR) [95% confidence interval] 1.23 [1.20-1.26], p<0.001) and diastolic dysfunction grading (chi-square 1217, HR 3.21 [3.00-3.42], p<0.001). In a separate multivariable model, there was an association with survival for both AVAD (chi-square 371, HR 1.27 [1.24-1.30], p<0.001) and E/e’ (chi-square 1020, HR 1.39 [1.36-1.42], p<0.001). Conclusions: Decreased hydraulic force, estimated as AVAD, is associated with diastolic dysfunction, and provides prognostic information beyond conventional measures used to grade diastolic dysfunction. This suggests that increased LA size relative to LV size is a potential therapeutic target in HFpEF.

Abstract 12420: Interleukin-38 Inhibits Nod-Like Receptor Protein 3 Inflammasomes to Suppress Aortic Valve Calcification

Calcific aortic valve disease (CAVD) is common in the elderly. Progressive valvular calcification is a characteristic pathobiology in CAVD, and chronic valvular inflammation is known to promote CAVD progression. Matrilin-2 is an extracellular matrix (ECM) protein. Soluble matrilin-2 can function as a damage - associated molecular pattern to induce the inflammatory and osteogenic responses in aortic valve interstitial cells (AVICs). Interleukin-38 (IL-38) is a novel anti-inflammatory cytokine. Lower IL-38 levels are associated with several chronic inflammatory diseases. Recent studies found that IL-38 limits skin inflammation and nephritis by reducing the inflammatory activity of immune cells. We hypothesized that IL-38 is capable of suppressing AVIC osteogenic activity. Methods and Results: We performed immunoblotting and ELISA to assess IL-38 protein levels in AVICs isolated from normal human aortic valves (normal AVICs) and diseased human aortic valves (diseased AVICs). Diseased AVICs had lower levels of IL-38 compared to normal AVICs. Interestingly, recombinant IL-38 inhibited spontaneous deposition of calcium in diseased AVICs. To determine the effect of recombinant IL-38 on AVIC osteogenic response to soluble matrilin-2, we treated normal AVICs with recombinant IL-38 (0, 1, 5 and 10 ng/ml) prior to an exposure to matrilin-2 for 24-72 hour. IL-38 at 10 ng/ml markedly reduced the expression of RUNX-2 and ALP in normal AVICs exposed to matrilin-2. Further, IL-38 suppressed calcium deposition in normal AVICs exposed to matrilin-2 for a prolonged period. Knockdown of IL-38 by shRNA enhanced the osteogenic responses and exaggerated the calcification deposit formation in normal AVICs exposed to matrilin-2. The anti-osteogenic effect of IL-38 is associated with down-regulation of Nod-like receptor protein 3 (NLRP3) inflammasomes, and inhibition of the NLRP3 inflammasomes also suppresses the osteogenic activity in normal AVICs exposed to matrilin-2. Conclusions: IL-38 suppresses the osteogenic activity in human AVICs by inhibiting NLRP3 inflammasomes. The novel findings of this study suggest that IL-38 may have therapeutic potential for prevention of CAVD progression.

Abstract 9316: Role of Bile Acids in Calcific Aortic Valve Stenosis

Introduction: Calcific aortic valve stenosis (CAVS) is the most common valvular pathology seen in the Western world. Patients with symptomatic CAVS have a poor prognosis with the only therapy being valvular intervention. There is currently no known mechanism and therefore medical therapy for controlling the progression of CAVS. Our recent metabolomics analysis of human aortic valve tissue identified bile acid biosynthesis as a potential mitigator of valvular stenosis. In this study, utilizing a targeted metabolomics approach, we investigated the role of valvular and plasma bile acids in the degree of severity and the rate of progression of CAVS. Methods: Human aortic valves from 102 patients who underwent AVR surgery were collected. Bile acid profiling (80 bile acids) of valvular tissues along with 19 plasma samples was carried out by a targeted mass spectrometry approach. The explanted aortic valves were graded from mild, moderate, and severe categories based on mean pressure gradient (MPG) and valvular calcification score by transthoracic echocardiography. CAVS progression was determined in a subset of our cohort (N=49), categorizing patients as “fast” and “slow” progressors based on echocardiography measures of the peak jet velocity. Results: Bile acids nordeoxycholic acid, norcholic acid, and glycodeoxycholic acid were significantly altered (p<0.05) across CAVS severity stages based on MPG. Similarly, six bile acids namely nordeoxycholic acid, norcholic acid, 3β,7α-diOH-5-cholestenoic acid, 3β-OH-5-cholestenoic acid, glycolithocholic acid, and glycoallocholic acid were significantly altered (p<0.05) based on valvular calcification scores. Taurodeoxycholic acid showed a significant difference (p<0.05) between the slow and fast progressors. Additionally, valvular tissue levels of these bile acids correlate with plasma levels. Conclusions: In this report, we present a potential novel mechanistic pathway correlating bile acids with the pathogenesis of CAVS. Our goal is to validate these findings in a large cohort of patients with CAVS. Given that bile acid modulating therapies are already used in clinical practice, this represents a potential novel therapeutic target to prevent or delay the progression of CAVS.

End-stage renal disease, calcification patterns and clinical outcomes after TAVI

BackgroundPatients with chronic hemodialysis due to end-stage renal disease (ESRD) or severely impaired kidney function (CKD) constitute a relevant share of patients undergoing trans-catheter aortic valve implantation (TAVI). However, data on specific challenges and outcomes remain limited.AimWe aimed to characterize this patient population, evaluate clinical results and assess the significance of calcification patterns.MethodsThis retrospective single-center analysis evaluated 2,712 TAVI procedures (2012–2019) according to baseline renal function: GFR < 30 ml/min/1.73m2 (CKD; n = 210), chronic hemodialysis (ESRD; n = 119) and control (CTRL; n = 2383). Valvular and vascular calcification patterns were assessed from contrast-enhanced multi-detector computed tomography. Outcomes were evaluated in accordance with the VARC-2 definitions.ResultsOperative risk was higher in ESRD and CKD vs. CTRL (STS-score 8.4% and 7.6% vs. 3.9%, p < 0.001) and patients with ESRD had more severe vascular calcifications (49.1% vs. 33.9% and 29.0%, p < 0.01). Immediate procedural results were similar but non-procedure-related major/life-threatening bleeding was higher in ESRD and CKD (5.0% and 5.3% vs. 1.6%, p < 0.01). 3-year survival was impaired in patients with ESRD and CKD (33.3% and 35.3% vs. 65.4%, p < 0.001). Multivariable analysis identified ESRD (HR 1.60), CKD (HR 1.79) and vascular calcifications (HR 1.29) as predictors for 3-year and vascular calcifications (HR 1.51) for 30-day mortality.ConclusionPatients with ESRD and CKD constitute a vulnerable patient group with extensive vascular calcifications. Immediate procedural results were largely unaffected by renal impairment, yielding TAVI a particularly valuable treatment option in these high-risk operative patients. Mid-term survival was determined by underlying renal disease, cardiovascular comorbidities, and vascular calcifications as a novel risk marker.Graphical abstract

Associations of endogenous sex hormone levels with the prevalence and progression of valvular and thoracic aortic calcification in the Multi-Ethnic Study of Atherosclerosis (MESA)

Background and aimsSex hormones (SH) may contribute to sex differences in cardiovascular disease (CVD). High free testosterone (T) and low sex hormone binding globulin (SHBG) have been associated with progression of coronary artery calcification in women. We now examined the association of SH with extra-coronary calcification (ECC) prevalence and progression among MESA participants. MethodsWe studied 2,737 postmenopausal women and 3,130 men free of clinical CVD with baseline SH levels. ECC measurements [ascending and descending thoracic aortic calcification (ATAC, DTAC), mitral annular calcification (MAC), aortic valve calcification (AVC)] were obtained by computed tomography at baseline and after 2.4 ± 0.9 years. We used multivariable Poisson regression to evaluate associations with ECC prevalence and incidence (Agatston scores >0) and linear mixed effects models for ECC progression, per 1-SD increment in log(SH) in women and men separately. ResultsThe mean age was 65 ± 9 and 62 ± 10 years for women and men, respectively. In women, greater free T and lower SHBG were associated with MAC incidence in a demographic-adjusted model only. In men, lower free T was associated with MAC prevalence, DTAC incidence and progression, while greater SHBG was associated with MAC prevalence and DTAC progression after further adjusting for CVD risk factors. ConclusionsIn this diverse cohort free of CVD, we found some associations of SH with ECC measures. In particular, free T was inversely associated with prevalent MAC and DTAC progression in men independent of CVD risk factors. SH may influence vascular calcification, but further work is needed to understand clinical implications of these findings.

Associations of adipokine levels with the prevalence and extent of valvular and thoracic aortic calcification: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background and aimsExtra-coronary calcification (ECC) is a marker of atherosclerosis and independently associated with cardiovascular disease (CVD). Adipokines may mediate the effect of obesity on atherosclerosis. However, the relationship of adipokines with ECC is not well-established. We examined the associations of leptin, resistin and adiponectin with ECC in a diverse community-based cohort. MethodsWe performed a cross-sectional analysis of 1897 adults without clinical CVD in the MESA cohort. Serum adipokine levels and non-contrast cardiac CT scans were obtained at Exam 2 or 3 (randomly assigned). ECC was quantified by Agatston score and included calcification of the mitral annulus (MAC), aortic valve (AVC), ascending thoracic aorta (ATAC) and descending thoracic aorta (DTAC). We used multivariable regression to evaluate the associations between leptin, resistin and adiponectin [per 1 SD ln(adipokine] with ECC prevalence (score >0) and extent [ln(score+1)]. ResultsThe mean age of participants was 65 ± 10 years; 49% women. After adjusting for demographic factors, adiponectin was inversely associated with AVC prevalence and extent; leptin positively associated with MAC prevalence and extent; and resistin positively associated with ATAC prevalence and extent and DTAC extent. After adjustment for BMI and other CVD risk factors, adiponectin remained inversely associated with AVC prevalence, and resistin remained associated with greater ATAC prevalence and extent. Leptin was not associated with measures of ECC after full adjustment. No adipokine was associated with MAC after full adjustment. ConclusionsWe identified significant associations between select adipokines and specific markers of ECC. Adipokines may play a role in the development of systemic atherosclerosis.

Chondroitin Sulfate Promotes Interstitial Cell Activation and Calcification in an In Vitro Model of the Aortic Valve.

Calcific aortic valve disease (CAVD), has been characterized as a cascade of cellular changes leading to leaflet thickening and valvular calcification. In diseased aortic valves, glycosaminoglycans (GAGs) normally found in the valve spongiosa migrate to the collagen I-rich fibrosa layer near calcified nodules. Current treatments for CAVD are limited to valve replacement or drugs tailored to other cardiovascular diseases. Porcine aortic valve interstitial cells and porcine aortic valve endothelial cells were seeded into collagen I hydrogels of varying initial stiffness or initial stiffness-matched collagen I hydrogels containing the glycosaminoglycans chondroitin sulfate (CS), hyaluronic acid (HA), or dermatan sulfate (DS). Assays were performed after 2 weeks in culture to determine cell gene expression, protein expression, protein secretion, and calcification. Multiple regression analyses were performed to determine the importance of initial hydrogel stiffness, GAGs, and the presence of endothelial cells on calcification, both with and without osteogenic medium. High initial stiffness hydrogels and osteogenic medium promoted calcification, while for DS or HA the presence of endothelial cells prevented calcification. CS was found to increase the expression of pro-calcific genes, increase activated myofibroblast protein expression, induce the secretion of collagen I by activated interstitial cells, and increase calcified nodule formation. This study demonstrates a more complete model of aortic valve disease, including endothelial cells, interstitial cells, and a stiff and disease-like ECM. In vitro models of both healthy and diseased valves can be useful for understanding the mechanisms of CAVD pathogenesis and provide a model for testing novel therapeutics.

Long-Term Effects of Sevelamer on Vascular Calcification, Arterial Stiffness, and Calcification Propensity in Patients Receiving Peritoneal Dialysis: The Randomized Pilot SERENE (Sevelamer on Vascular Calcification, Arterial Stiffness) Trial

Rationale & ObjectiveThere is a concern regarding increased risk of vascular calcification with the use of calcium-based phosphorus binders. This study aimed to compare the effects of sevelamer used as a second-line, low-dose therapy with calcium-based phosphorus binders with those of sevelamer used as a first-line, high-dose therapy on coronary artery and heart valve calcification, aortic pulse wave velocity (PWV), and calcification propensity over 2 years in patients with hyperphosphatemia receiving peritoneal dialysis (PD).Study DesignA 2-year-long prospective, multicenter, open-label, randomized pilot study.Setting & ParticipantsPrevalent patients with hyperphosphatemia receiving PD from 2 university-affiliated hospitals in Hong Kong.InterventionsThe patients were randomized to receive sevelamer either as a first-line therapy at a high dose of 800 mg thrice daily (can titrate up to 1,200 mg thrice daily as required) or a second-line therapy at a low dose of 400 mg thrice daily with calcium carbonate to achieve a serum phosphorus target of ≤5.5 mg/dL.OutcomesThe primary endpoints were changes in coronary artery calcium score and aortic PWV over 104 weeks. The secondary endpoints were changes in heart valve calcium scores, calcification propensity measure, and biochemical parameters of chronic kidney disease–mineral bone disease over 104 weeks.ResultsAmong 60 prevalent patients receiving PD, with a mean age of 53 ± 10 years and with 57% men, changes in the coronary artery calcium score (median [interquartile range], 225 [79-525] vs 223 [56-1,212], respectively; P = 0.21), aortic PWV (mean ± standard error, 0.3 ± 0.1 vs 0.8 ± 0.2 m/s, respectively; P = 0.31), heart valve calcium score, maturation or transformation time, serum calcium levels, and phosphorus levels over 104 weeks were similar for the second-line, low-dose and first-line, high-dose sevelamer groups. Alkaline phosphatase and intact parathyroid hormone levels increased and low-density lipoprotein cholesterol decreased in both the groups, with no significant between-group differences.LimitationsThe sample size was small, and the dropout rates were relatively high.ConclusionsLow-dose sevelamer used as a second-line therapy for hyperphosphatemia in combination with a calcium-based phosphorus binder had similar effects on vascular calcification, valvular calcification, and arterial stiffness compared with high-dose sevelamer used as a first-line therapy. This approach may be considered in resource-constrained countries to minimize calcium loading.FundingThe study was supported by a competitive grant from SK Yee Medical Foundation. T50 assays and other biochemical assays were funded by a research grant from Sanofi Renal Corporation.Trial RegistrationNCT00745589.

Diabetes mellitus as a risk factor for aortic stenosis: from new mechanisms to clinical implications.

Aortic stenosis (AS) is a progressive disease, with no pharmacological treatment. The prevalence of diabetes mellitus (DM) among AS patients is higher than in the general population. DM significantly increases the risk of AS development and the rate of its progression from mild to severe. However, the mechanism of the interaction between AS and DM is not fully understood. Limited data regarding the influence of hyperglycemia on valvular calcification are available while understanding the cross-talk between them is pivotal in designing an effective therapeutic approach to prevent or at least retard AS development and/or progression in DM patients. Analysis of aortic stenotic valves revealed that increased accumulation of advanced glycoxidation end products (AGEs) was associated with enhanced valvular oxidative stress, inflammation, expression of coagulation factors and markers of calcification. Moreover, AGEs valvular expression correlated with AS severity. Interestingly, in diabetic AS patients, valvular inflammation correlated only with long-term glycemic control parameters, i.e. glycated hemoglobin and fructosamine but not with serum glucose levels. It has been demonstrated that transcatheter aortic valve replacement (TAVI) is beneficial for AS patients also with concomitant DM and safer as compared to surgical aortic valve replacement (SAVR). Moreover, new antidiabetic drugs, such as glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors, targeting inhibition of AGEs-mediated oxidative stress, have been proposed to reduce the risk of AS development in DM patients. This review aimed to comprehensively discuss the impact of DM on AS and its potential therapeutic implications.

The incidence and predictors of high-degree atrioventricular block in patients with bicuspid aortic valve receiving self-expandable transcatheter aortic valve implantation.

BACKGROUNDThe high-degree atrioventricular block (HAVB) in patients with bicuspid aortic valve (BAV) treated with transcatheter aortic valve implantation (TAVI) remains high. The study aims to explore this poorly understood subject of mechanisms and predictors for HAVB in BAV self-expandable TAVI patients.METHODSWe retrospectively included 181 BAV patients for analysis. Using computed tomography data, the curvature of ascending aorta (AAo) was quantified by the angle (AAo angle) between annulus and the cross-section at 35 mm above annulus (where the stent interacts with AAo the most). The valvular anatomy and leaflet calcification were also characterized.RESULTSThe 30-day HAVB rate was 16.0% (median time to HAVB was three days). Type-1 morphology was found in 79 patients (43.6%) (left- and right-coronary cusps fusion comprised 79.7%). Besides implantation below membrane septum, large AAo angle [odds ratio (OR) = 1.08, P = 0.016] and type-1 morphology (OR = 4.97, P = 0.001) were found as the independent predictors for HAVB. Together with baseline right bundle branch block, these predictors showed strong predictability for HAVB with area under the cure of 0.84 (sensitivity = 62.1%, specificity = 92.8%). Bent AAo and calcified raphe had a synergistic effect in facilitating high implantation, though the former is associated with at-risk deployment (device implanted above annulus + prothesis pop-out, versus straight AAo: 9.9% vs. 2.2%, P = 0.031). CONCLUSIONSAAo curvature and type-1 morphology are novel predictors for HAVB in BAV patients following self-expandable TAVI. For patients with bent AAo or calcified raphe, a progressive approach to implant the device above the lower edge of membrane septum is favored, though should be done cautiously to avoid pop-out.

A novel deep intronic variant strongly associates with Alkaptonuria

Alkaptonuria is a rare autosomal recessive inherited disorder of tyrosine metabolism, which causes ochronosis, arthropathy, cardiac valvular calcification, and urolithiasis. The epidemiology of alkaptonuria in East Asia is not clear. In this study, patients diagnosed with alkaptonuria from January 2010 to June 2020 were reviewed. Their clinical and molecular features were further compared with those of patients from other countries. Three patients were found to have alkaptonuria. Mutation analyses of the homogentisate 1,2-dioxygenase gene (HGD) showed four novel variants c.16-2063 A > C, p.(Thr196Ile), p.(Gly344AspfsTer25), and p.(Gly362Arg) in six mutated alleles (83.3%). RNA sequencing revealed that c.16-2063 A > C activates a cryptic exon, causing protein truncation p.(Tyr5_Ile6insValTer17). A literature search identified another 6 patients with alkaptonuria in East Asia; including our cases, 13 of the 18 mutated alleles have not been reported elsewhere in the world. Alkaptonuria is rare in Taiwan and East Asia, with HGD variants being mostly novel and private.

The timing and mechanism of high-grade AV block post-TAVI: knowing your enemy

Abstract Background Complete atrioventricular block (AVB) requiring permanent pacemaker implantation (PPMI) is still a major limitation of transcatheter aortic valve implantation (TAVI) procedures. Although right-bundle branch block (RBBB), membranous septum (MS) length and self-expandable prothesis are recognizable risk factors, their predictability to PPMI is far from satisfactory. While some patients develop persistent intra-procedure high-grade AVB (H-AVB), others present much later with severe bradycardia. Purpose This study aims to describe and compare the characteristics of patients who develop AVB during or after TAVI. Methods Single centre prospective registry of 506 consecutive patients submitted to TAVI with no previous pacemaker between 2017 and 2020. Post-procedure PPMI (up to 30 days after discharge) was studied and divided into two groups according to the development of persistent intra-procedure H-AVB (Group A) or post procedure H-AVB (Group B). Baseline ECG, computed tomography and TAVI-related characteristics were analyzed. Results A total of 88 patients (17,3%), aging 83±6 years, 36.4% male, underwent post-TAVI PPMI (6 after discharge). Previous conduction disturbances were present in 50 (56.8%) patients and 25 (28.4%) had RBBB. 83% were submitted to self-expandable TAVI. Forty-two patients (47.7%) had persistent intra-procedure H-AVB (Group A) whereas 52.3% had post-procedure H-AVB (Group B). In patients with persistent intra procedure H-AVB previous RBBB was significantly more frequent (45.2%, n=19) when compared to patients with post-procedure H-AVB (13%, n=6; p=0.001). Contrarily, AF and previous left-bundle branch block (LBBB) were more likely in Group B. No difference in valvular calcification, MS length, prosthesis type or implantation technique was noted (picture 1). In the group with post-procedure H-AVB, 21.7% had transient AVB during TAVI and all developed de novo LBBB or first-degree AVB post-TAVI. Among these, 33 patients (71.7%) developed delayed H-AVB (&amp;gt;48h post-procedure) while the remaining presented earlier. Conclusions In patients with PPMI post-TAVI, those with persistent intra-procedure H-AVB had higher rates of previous RBBB, while those with post-procedure H-AVB frequently had a normal baseline ECG. Anatomical and procedural characteristics did not differ between groups. Further studies are needed to confirm these results. Funding Acknowledgement Type of funding sources: None.

Arterial stiffness and valvular calcifications in aortic stenosis: caught between a rock and a hard place

Abstract Background/Introduction Arterial stiffness and aortic hemodynamics are independent predictors of adverse cardiovascular events. Indications for transcatheter aortic valve implantation (TAVI) are expanding and aortic valve calcifications (AVC) are an important prognostic factor of the success of TAVI. Purpose We sought to investigate the associations between AVC and aortic vascular function/hemodynamics. Methods Fifty-two high-risk patients (mean age 80.4±8.5 years, 27 male) with severe symptomatic aortic stenosis undergoing TAVI were included. Arterial stiffness was estimated through carotid-femoral pulse wave velocity (cfPWV) and brachial-ankle pulse wave velocity (baPWV). Aortic hemodynamics (aortic pressures, aortic augmentation index corrected for heart rate [AIx@75]) were also measured. Measurements were conducted prior to the implantation and at discharge. In all patients, a native and contrast-enhanced multislice cardiac computed tomography were performed pre-interventionally. AVC were then graded semi-quantitatively as follows: grade 1 – no calcification; grade 2 – mildly calcified (small isolated spots); grade 3 – moderately calcified (multiple larger spots); grade 4 – severely calcified (extensive calcification of all cusps). Results Group 1 (subjects with none/mild AVC, n=29) did not significantly differ in age, gender and body-mass index compared to group 2 (subjects with moderate/severe AVC, n=23). As far as the traditional cardiovascular risk factors were concerned, only hypertension (p=0.008), coronary artery disease (p=0.016), atrial fibrillation (p=0.075) and insulin-dependent diabetes mellitus (p=0.068) were found to be more prevalent in group 2. Group 2 had significantly higher both cfPWV and baPWV (8.3±1.7 vs 7.2±1.2 m/s and 1750±484 cm/s vs. 2101±590 cm/s with p=0.008 and p=0.022 respectively) compared to Group 1 (Figure 1). Even after adjustment for age, gender and systolic blood pressure, aortic stiffness indices were higher in Group 2 compared to Group 1 (p=0.038 and p=0.048, respectively). There was no statistically significant difference in peripheral or aortic pressures as well as in wave reflections indices between the two groups. Conclusion Our study shows that in patients with aortic valve stenosis there is a correlation between increased aortic stiffness and a greater extent of damage of aortic valvular leaflets as well as calcifications. Funding Acknowledgement Type of funding sources: None. Figure 1. PWV and aortic valve calcifications

Relation Between Matrix Gla Protein and Cardiac Vavular Calcifications in Haemodialysis Patients

Abstract Background Heart valve calcification was first described a century ago. Its pathologic features were first described by Dewitsky in 1910. Valvular heart disease is common in end-stage renal disease patients. The incidence of valvular heart disease is 5 times greater in dialysis patients than in the general population MGP plays a key role in the inhibition of tissue calcification, which was demonstrated in MGP-deficient mice Objective To detect the prevalence of cardiac valvular calcifications among end stage renal disease patients on prevalent haemodialysis and its relation to Matirx Gla protein. Patients and Methods Enrolled patients were recruited from Ain shams hospitals, divided into two groups according to the presence/absence of valvular calcifications on echocardiographic examination as follows: Group A: included patients with valvular calcifications. Group B: included patients without valvular calcifications. Results In current study, 19 (23.8%) patients showed mitral calcification, 30 (37.5%) showed aortic calcification and 44 (55.0%) had calcification in general as 5 patients had both mitral and aortic calcifications. In current study, the patient who had calcification were significantly older, heavier in weight and BMI and were had HD for longer than those who didn’t have calcification. Patient who had calcification had lower levels of both platelets and urea than those who didn’t have calcification. In current study, the mean ucMGP was 549.5 ± 160.1 and the patient who had calcification had higher levels of ucMGP than those who did not have calcification. There was a significant positive correlation between age, weight, BMI, duration of HD and ucMGP. And there was a significant negative correlation between platelet count, serum albumin and ucMGP. Conclusion In current study, MGP was able to significantly differentiate between patients with and without calcification at a cutoff point (&amp;gt;564 pg/mlv) with sensitivity 86.36%, specificity 97.22. Our study confirmed that older age, hypertension, diabetes mellitus low platelet, higher ucMGP and blood urea are the most predictive parameters of valvular calcifications in hemodialysis patients. Other markers were not associated with valvular calcifications. ucMGP serum levels can significantly differentiate between HD cases with valvular calcifications and those not and those who had findings in CXR.

Effect of hyperparathyroidism on vascular stiffness in hemodialysis patients

Abstract Background Cardiovascular disease (CVD) is present in &amp;gt; 50% of patients undergoing dialysis and the relative risk of death due to CVD events in HD patients is reported to be 20 times higher than in the general population. In fact, in patients on renal replacement therapy (RRT) the prevalence of coronary heart disease and ventricular hypertrophy has been described to be 40% and 70% respectively, other CVD events include hypertention, arrhythmias, valvular calcification and arterial stiffness. Objective To detect the prevalence of arterial stiffness among end stage renal disease patients on prevalent hemodialysis with hyperparathyroidism. Patients and Methods This observational cross sectional study was conducted on 60 prevalent hemodialysis patients attending at hemodialysis unit of Ain Shams University hospitals, with convenient sampling method. The included patients are clinically stable on thrice weekly hemodialysis sessions for 4 hours per session. Results The Dual Pulse Wave Doppler (DPWD) method we proposed in this study may be considered as a useful and convenient option for clinical local Pulse Wave Velocity (PWV) measurement, this clinical practical and reproducible method had the capability to detect an increased local PWV of LCCA (which reflect arterial stiffness) in the patients with PTH &amp;gt; 300 more than the patients with PTH &amp;lt; 300 as it showed that in Group B (PTH&amp;gt;300), the measured carotid artery local PWV values ranged from 6.22 m/s to 8.84 m/s and the mean value was 7.81 ± 0.72 m/s, which was higher than 6.72 ± 1.06 m/s (ranging from 4.48 m/s to 8.44 m/s) of Group A (PTH&amp;lt;300). Conclusion Our study showed that there is a high prevalence of arterial stiffness in prevalent hemodialysis patients.

Correlation between Peri-Coronary Epicardial Adipose Tissue Volume, Cardiac Calcification and the Severity of Coronary Artery Disease by Multi Slice Computed Tomography

ABSTRACT The authors in that article addressed a very important and relevant issue. Background Epicardial adipose tissue (EAT) is a complex endocrine organ that plays an important role in the development of unfavorable metabolic and cardiovascular risk profile. EAT may express a variety of inflammatory mediators which may contribute to the pathogenesis of coronary artery disease (CAD). Aortic and mitral valve calcification may reflect generalized atherosclerosis in the elderly and may be a marker of high prevalence and severity of CAD. There is a direct correlation (extent, severity and the future CV events) between the coronary artery calcium and the CAD. Aim and Objectives To correlate peri-coronary epicardial adipose tissue and coronary artery calcification and valvular (aortic and mitral) calcification with the severity of the coronary artery disease. Patients and Methods The study recruited 200 patients with suspected coronary artery disease. The amount of EAT surrounding the left main and the three main coronary arteries was quantified in axial cuts with the most distinct layer of EAT. The amount of calcium in the aortic and mitral valve and the coronaries were quantified with multi-detector computed tomography MDCT using dedicated software for measuring calcium score that is based on Agatson score. Coronary artery disease severity was assessed in terms of number of vessels affected and the severity of coronary stenosis by multi-planner reformation technique. Results Based on the finding of the MDCT and according to the presence of calcification in the aortic or the mitral valves, and the significance of the coronary artery disease, patients were classified into two groups, group (I): 115 patients with normal coronaries or with non significant lesions in their coronaries, and group (II): 85 patients with significant coronary artery disease. The Mean ± SD (in millimeters) of EAT for the entire study cohort in various coronary artery locations were as follows: LM EAT 9.82 ± 2.67, proximal LAD EAT 10.06 ± 2.80, mid LAD EAT 9.15 ± 2.41, distal LAD EAT 6.46 ± 1.87, proximal LCX EAT 8.10 ± 1.90, distal LCX EAT 6.83 ± 1.79, proximal RCA EAT 10.23 ± 2.42, mid RCA EAT 9.26 ± 2.72, distal RCA EAT 7.25 ± 2.58. Statistically highly significant difference was observed between the two groups with regards to LM EAT, proximal, mid and distal LAD EAT, proximal and distal LCX EAT, proximal, mid and distal RCA EAT (8.38 ± 2.18 Vs 11.77 ± 1.94 P: 0.000, 8.49 ± 2.21 Vs 12.18 ± 2.00, 7.93 ± 1.77 Vs 10.81 ± 2.16, 5.45 ± 1.26 Vs 7.82 ± 1.68 P: 0.000, 7.08 ± 1.34 Vs 9.46 ± 1.67, 6.05 ± 1.50 Vs 7.89 ± 1.61 P: 0.000, 9.01 ± 1.94 Vs 11.88 ± 1.99, 8.07 ± 2.32 Vs 10.86 ± 2.39, 6.31 ± 2.26 Vs 8.51 ± 2.45 P: 0.000; respectively). Statistically highly significant difference was observed between the two groups with regards calcium score and the severity of CAD in the three major vessels (LAD, LCX and RCA) and the total calcium score in all vessels (35 (16 – 85.5) Vs 179.5 (59.5 – 243) P: 0.000, 20.5 (7 – 50.5) Vs 56 (33 – 95) P: 0.000, 31 (9 – 54) Vs 97 (54 – 199) P: 0.000, 12 (0 – 84) Vs 286 (106 – 511) P:0.000; respectively) while calcium score in the LM was not statistically significant with the severity of CAD (4 (3 – 26) Vs 12 (9 – 16) P: 0.360). As regards aortic valve calcification there was statistically highly significant difference between the two groups; P value 0.000, while mitral valve calcification was found to be not statistically significant between the two groups P: 0.272. Conclusion The present study demonstrated a significant correlation between the peri-coronary epicardial adipose tissue, coronary calcification and aortic valve calcification and the severity of the coronary artery disease.

Micro-Physiological-Systems enable investigation of hypoxia induced pathological processes in human aortic valve cells and tissues

Abstract Aortic valve (AV) stenosis is characterized by tissue fibrosis and calcification. Fibrous thickening can result in reduced tissue oxygen supply leading to pathological valvular interstitial cell (VIC) differentiation and calcification. Static 2D VIC cultures and animal models are limited in the ability to reflect human AV calcification. Culturing of VICs in micro-physiological-systems (MPS) in a pulsatile flow and the establishment of a modular AV tissue incubation chamber (TIC) are new approaches to evaluate pathophysiological processes of AV disease. Therefore, a MPS able to adjust hypoxic conditions was applied for VIC culture. A significant increase of mRNA-expression of EGLN1 and HIF1α- regulated LDHA and HIF1α nuclear localisation were proven under hypoxia. AV tissue culture was established within a TIC and viability was monitored by Resazurin-reduction in the incubation medium and visualized by LDH-activity in tissue cryosections. Viability was compared between fluid and static incubated tissues revealing an advantageous effect of the fluidic assay condition. Consecutively, the application of MPS in AV research allows i) the investigation of VIC cultures with efficient oxygen regulation and ii) the culture of porcine or human AV tissues preserving viability and specifically reflecting in vivo parameters. These methods open up new possibilities beyond static 2D culture and facilitate a reduction of animal experiments in AV research.