Effect of Blood Pressure Levels on Sinus Hemodynamics in Relation to Calcification After Bioprosthetic Aortic Valve Replacement

Coexisting hypertension and aortic stenosis are common. Some studies showed that elevated blood pressures may be associated with progression of calcific aortic valve disease (CAVD) while others showed no correlation. Flow dynamics in the sinuses of Valsalva are considered key factors in the progression of CAVD. While the relationship between hemodynamics and CAVD is not yet fully understood, it has been demonstrated that they are tightly correlated. This study aims to investigate the effect of changing systolic and diastolic blood pressures (SBP and DBP, respectively) on sinus hemodynamics in relation to potential initiation or progression of CAVD after aortic valve replacement (AVR). Evolut R, SAPIEN 3 and Magna valves were deployed in an aortic root under pulsatile conditions. Using particle image velocimetry, the hemodynamics in the sinus were assessed. The velocity, vorticity, circulation ( Γ ) and shear stress were calculated. This study shows that under elevated SBP and DBP, velocity, vorticity, and shear stress nearby the leaflets increased. Additionally, larger fluctuations of Γ and area under the curve throughout the cardiac cycle were observed. Elevated blood pressures are associated with higher velocity, vorticity, and shear stress near the leaflets which may initiate or accelerate pro-calcific changes in the prosthetic leaflets leading to bioprosthetic valve degeneration.

Aortic valve neocuspidization and bioprosthetic valves: Evaluating turbulence haemodynamics

Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects have yet to be evaluated in either bioprosthetic or aortic valve neocuspidization valve types in patient-specific settings. The aim of this study is to better understand turbulence production in the aorta and evaluate its effects on laminar and turbulent wall shear stress. Four patients with aortic valve disease were treated with either bioprosthetic valves (n=2) or aortic valve neocuspidization valvular repair (n=2). Aortic geometries were segmented from magnetic resonance images (MRI), and 4D flow MRI was used to derive physiological inlet and outlet boundary conditions. Pulsatile large-eddy simulations were performed to capture the full range of laminar, transitional and turbulence characteristics in the aorta. Turbulence was produced in all aortas with highest levels occurring during systolic deceleration. In the ascending aorta, turbulence production is attributed to a combination of valvular skew, valvular eccentricity, and ascending aortic dilation. In the proximal descending thoracic aorta, turbulence production is dependent on the type of arch-descending aorta connection (e.g., a narrowing or sharp bend) which induces flow separation. Laminar and turbulent wall shear stresses are of similar magnitude throughout late systolic deceleration and diastole, although turbulent wall shear stress magnitudes exceed laminar wall shear stresses between 27.3% and 61.1% of the cardiac cycle. This emphasises the significance of including turbulent wall shear stress to improve our comprehension of progressive arterial wall diseases. The findings of this study recommend that aortic valve treatments should prioritise minimising valvular eccentricity and skew in order to mitigate turbulence generation.

Novel contouring method for optimizing MRI flow quantification in patients with aortic valve disease

Optimizing MRI aortic flow quantification is crucial for accurate assessment of valvular disease severity. In this study, we sought to evaluate the accuracy of a novel method of contouring systolic aortic forward flow in comparison to standard contouring methods at various aortic levels. The study included a cohort of patients with native aortic valve (AoV) disease and a small control group referred to cardiac MRI over a 1-year period. Inclusion criteria included aortic flow quantification at aortic valve and one additional level, and no or trace mitral regurgitation (MR) documented both by the MRI AND an echocardiogram done within a year. In addition to flow quantification with standard contouring (SC), a novel Selective Systolic Contouring (SSC) method was performed at aortic valve level, contouring the area demarcated by the AoV leaflets in systole. The bias in each technique's estimate of aortic forward flow was calculated as the mean difference between aortic forward flow and left ventricular stroke volume (LV SV). 98 patients (mean age 56, 71% male) were included: 33 with tricuspid and 65 with congenitally abnormal (bicuspid or unicuspid) AoV. All methods tended to underestimate aortic forward flow, but the bias was smallest with the SSC method (p < 0.001). Therefore, SSC yielded the lowest estimates of mitral regurgitant volume (4.8 ml) and regurgitant fraction (3.9%) (p < 0.05). SSC at AoV level better approximates LV SV in our cohort, and may provide more accurate quantitative assessment of both aortic and mitral valve function.

The Role of Apoptosis and Oxidative Stress in a Cell Spheroid Model of Calcific Aortic Valve Disease

Calcific aortic valve disease (CAVD) is the most common heart valve disease among aging populations. There are two reported pathways of CAVD: osteogenic and dystrophic, the latter being more prevalent. Current two-dimensional (2D) in vitro CAVD models have shed light on the disease but lack three-dimensional (3D) cell-ECM interactions, and current 3D models require osteogenic media to induce calcification. The goal of this work is to develop a 3D dystrophic calcification model. We hypothesize that, as with 2D cell-based CAVD models, programmed cell death (apoptosis) is integral to calcification. We model the cell aggregation observed in CAVD by creating porcine valvular interstitial cell spheroids in agarose microwells. Upon culture in complete growth media (DMEM with serum), calcium nodules form in the spheroids within a few days. Inhibiting apoptosis with Z-VAD significantly reduced calcification, indicating that the calcification observed in this model is dystrophic rather than osteogenic. To determine the relative roles of oxidative stress and extracellular matrix (ECM) production in the induction of apoptosis and subsequent calcification, the media was supplemented with antioxidants with differing effects on ECM formation (ascorbic acid (AA), Trolox, or Methionine). All three antioxidants significantly reduced calcification as measured by Von Kossa staining, with the percentages of calcification per area of AA, Trolox, Methionine, and the non-antioxidant-treated control on day 7 equaling 0.17%, 2.5%, 6.0%, and 7.7%, respectively. As ZVAD and AA almost entirely inhibit calcification, apoptosis does not appear to be caused by a lack of diffusion of oxygen and metabolites within the small spheroids. Further, the observation that AA treatment reduces calcification significantly more than the other antioxidants indicates that the ECM stimulatory effect of AA plays a role inhibiting apoptosis and calcification in the spheroids. We conclude that, in this 3D in vitro model, both oxidative stress and ECM production play crucial roles in dystrophic calcification and may be viable therapeutic targets for preventing CAVD.

Limited versus full sternotomy for aortic valve replacement

BACKGROUND

Aortic valve disease is a common condition easily treatable with cardiac surgery. This is conventionally performed by opening the sternum ('median sternotomy') and replacing the valve under cardiopulmonary bypass. Median sternotomy is well tolerated, but as less invasive options become available, the efficacy of limited incisions has been called into question. In particular, the effects of reducing the visibility and surgical access have raised safety concerns with regard to the placement of cannulae, venting of the heart, epicardial wire placement, and de-airing of the heart at the end of the procedure. These difficulties may increase operating times, affecting outcome. The benefits of smaller incisions are thought to include decreased pain; improved respiratory mechanics; reductions in wound infections, bleeding, and need for transfusion; shorter intensive care stay; better cosmesis; and a quicker return to normal activity. This is an update of a Cochrane review first published in 2017, with seven new studies.

OBJECTIVES

To assess the effects of minimally invasive aortic valve replacement via a limited sternotomy versus conventional aortic valve replacement via median sternotomy in people with aortic valve disease requiring surgical replacement.

SEARCH METHODS

We performed searches of CENTRAL, MEDLINE and Embase from inception to August 2021, with no language limitations. We also searched two clinical trials registries and manufacturers' websites. We reviewed references of primary studies to identify any further studies of relevance.

SELECTION CRITERIA

We included randomised controlled trials comparing aortic valve replacement via a median sternotomy versus aortic valve replacement via a limited sternotomy. We excluded trials that performed other minimally invasive incisions such as mini-thoracotomies, port access, transapical, transfemoral or robotic procedures. Although some well-conducted prospective and retrospective case-control and cohort studies exist, these were not included in this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial papers to extract data, assess quality, and identify risk of bias. A third review author provided arbitration where required. We determined the certainty of evidence using the GRADE methodology and summarised results of patient-relevant outcomes in a summary of findings table.

MAIN RESULTS

The review included 14 trials with 1395 participants. Most studies had at least two domains at high risk of bias. We analysed 14 outcomes investigating the effects of minimally invasive limited upper hemi-sternotomy on aortic valve replacement as compared to surgery performed via full median sternotomy. Upper hemi-sternotomy may have little to no effect on mortality versus full median sternotomy (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.45 to 1.94; 10 studies, 985 participants; low-certainty evidence). Upper hemi-sternotomy for aortic valve replacement may increase cardiopulmonary bypass time slightly, although the evidence is very uncertain (mean difference (MD) 10.63 minutes, 95% CI 3.39 to 17.88; 10 studies, 1043 participants; very low-certainty evidence) and may increase aortic cross-clamp time slightly (MD 6.07 minutes, 95% CI 0.79 to 11.35; 12 studies, 1235 participants; very low-certainty evidence), although the evidence is very uncertain. Most studies had at least two domains at high risk of bias. Postoperative blood loss was probably lower in the upper hemi-sternotomy group (MD -153 mL, 95% CI -246 to -60; 8 studies, 767 participants; moderate-certainty evidence). Low-certainty evidence suggested that there may be no change in pain scores by upper hemi-sternotomy (standardised mean difference (SMD) -0.19, 95% CI -0.43 to 0.04; 5 studies, 649 participants). Upper hemi-sternotomy may result in little to no difference in quality of life (MD 0.03 higher, 95% CI 0 to 0.06 higher; 4 studies, 624 participants; low-certainty evidence). Two studies reporting index admission costs concluded that limited sternotomy may be more costly at index admission in the UK National Health Service (MD 1190 GBP more, 95% CI 420 GBP to 1970 GBP, 2 studies, 492 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence was of very low to moderate certainty. Sample sizes were small and underpowered to demonstrate differences in some outcomes. Clinical heterogeneity was also noted. Considering these limitations, there may be little to no effect on mortality. Differences in extracorporeal support times are uncertain, comparing upper hemi-sternotomy to full sternotomy for aortic valve replacement. Before widespread adoption of the minimally invasive approach can be recommended, there is a need for a well-designed and adequately powered prospective randomised controlled trial. Such a study would benefit from also performing a robust cost analysis. Growing patient preference for minimally invasive techniques merits thorough quality of life analyses to be included as end points, as well as quantitative measures of physiological reserve.

Molecular Mechanism of Berberine in the Treatment of Calcified Aortic Valve Disease Based on AGE-RAGE Signal Pathway

Objective

We aimed to explore the molecular mechanism of berberine in the treatment of calcified aortic valve disease through the network pharmacology-molecular docking method.

Methods

The targets of berberine and calcified aortic valve disease were retrieved, the interactions between the targets were analyzed, Cytoscape software was used to build a "target-path" network, R language was used to conduct enrichment analysis of GO and KEGG pathways, and AutoDock Vina was used to verify the binding force of the target protein and small molecules.

Results

96 targets for berberine and 4293 disease targets were screened through multiple databases, and 56 targets were identified through veen analysis. The enrichment of PPI, GO, and KEGG pathways suggests that berberine may act on PIK3CD, PIK3CB, PIK3R1, MAPK14, MAPK10, and other targets, and regulate the role of calcified aortic valve disease through AGE-RAGE signaling pathway, Chemokine signaling pathway, Lipid and atherosclerosis, and other pathways. The docking results showed that berberine has good binding activity with the target on the key pathway AGE-RAGE signaling pathway.

Conclusion

The network pharmacology preliminarily revealed the mechanism of berberine in the treatment of calcified aortic valve disease by regulating vascular calcification, inflammatory reaction, oxidative stress, and other effects, providing the basis for follow-up experimental research, and also providing the basis for clinical medication.

Alerting trends in epidemiology for calcific aortic valve disease, 1990-2019: An age-period-cohort analysis for the Global Burden of Disease Study 2019

AIMS

To assess the trends in calcific aortic valve disease (CAVD) epidemiology, with an emphasis on CAVD mortality, leading risk factors, and their associations with age, period, and birth cohort.

METHODS AND RESULTS

Prevalence, disability-adjusted life years, and mortality were derived from the Global Burden of Disease Study 2019. The age-period-cohort model was employed to study the detailed trends of CAVD mortality and its leading risk factors. Globally, CAVD showed unsatisfactory results from 1990 to 2019, with the CAVD deaths of 127 000 in 2019. CAVD mortality was substantially reduced in high socio-demographic index (SDI) countries [-1.45%, 95% confidence interval (CI) (-1.61 to -1.30)], mildly increased in high-middle SDI countries [0.22%, 95% CI (0.06-0.37)], and unchanged in other SDI quintiles. There was a noticeable transition in CAVD deaths from younger to older populations globally. The CAVD mortality increased exponentially with age, and the male had higher mortality than the female before 80 years old. Favourable period [0.69, 95% CI (0.66-0.72)] and birth effects [0.30, 95% CI (0.22-0.43)] were mainly observed in high SDI countries, while unfavourable effects were mostly noticed in high-middle SDI countries. High systolic blood pressure was the leading risk factor of CAVD deaths globally, and it showed favourable trends in high SDI regions.

CONCLUSION

Although CAVD mortality reduction was observed globally, unfavourable period, and cohort effects were found in many countries. Increase of mortality rate among the population ≥85 years was the common challenge across all SDI quintiles, stressing the necessity to further improve health care for CAVD patients worldwide.

Aortic Valve Disease, Transcatheter Aortic Valve Replacement, and the Heart Failure Patient: A State-of-the-Art Review

Concomitant aortic stenosis (AS) in heart failure (HF) is associated with high rates of mortality and morbidity. Current guidelines recommend aortic valve replacement in patients with severe symptomatic AS and asymptomatic AS with left ventricular ejection fraction <50% and during other cardiac surgeries. Transcatheter aortic valve replacement (TAVR) has now allowed for the treatment of severe AS in previously inoperable or high-surgical-risk patients. Leveraging multimodality imaging techniques is increasingly recognized for reinforcing the rationale for intervening early, thus mitigating the risk of ongoing progression to advanced HF. There are increasing data in favor of TAVR in diverse clinical scenarios, particularly asymptomatic AS and moderate AS. Limited information is, however, available regarding the advantages of HF medical therapy before and after intervention. This review aims to comprehensively examine the phenotypes of AS in the context of HF progression, while exploring the evolving role of TAVR in specific populations.

Single-cell transcriptomics reveals cellular heterogeneity and macrophage-to-mesenchymal transition in bicuspid calcific aortic valve disease

BACKGROUND

Bicuspid aortic valve (BAV) is the most prevalent congenital valvular heart defect, and around 50% of severe isolated calcific aortic valve disease (CAVD) cases are associated with BAV. Although previous studies have demonstrated the cellular heterogeneity of aortic valves, the cellular composition of specific BAV at the single-cell level remains unclear.

METHODS

Four BAV specimens from aortic valve stenosis patients were collected to conduct single-cell RNA sequencing (scRNA-seq). In vitro experiments were performed to further validate some phenotypes.

RESULTS

The heterogeneity of stromal cells and immune cells were revealed based on comprehensive analysis. We identified twelve subclusters of VICs, four subclusters of ECs, six subclusters of lymphocytes, six subclusters of monocytic cells and one cluster of mast cells. Based on the detailed cell atlas, we constructed a cellular interaction network. Several novel cell types were identified, and we provided evidence for established mechanisms on valvular calcification. Furthermore, when exploring the monocytic lineage, a special population, macrophage derived stromal cells (MDSC), was revealed to be originated from MRC1+ (CD206) macrophages (Macrophage-to-Mesenchymal transition, MMT). FOXC1 and PI3K-AKT pathway were identified as potential regulators of MMT through scRNA analysis and in vitro experiments.

CONCLUSIONS

With an unbiased scRNA-seq approach, we identified a full spectrum of cell populations and a cellular interaction network in stenotic BAVs, which may provide insights for further research on CAVD. Notably, the exploration on mechanism of MMT might provide potential therapeutic targets for bicuspid CAVD.

Effect of cardioplegic arrest and reperfusion on left and right ventricular proteome/phosphoproteome in patients undergoing surgery for coronary or aortic valve disease

Our earlier work has shown inter‑disease and intra‑disease differences in the cardiac proteome between right (RV) and left (LV) ventricles of patients with aortic valve stenosis (AVS) or coronary artery disease (CAD). Whether disease remodeling also affects acute changes occuring in the proteome during surgical intervention is unknown. This study investigated the effects of cardioplegic arrest on cardiac proteins/phosphoproteins in LV and RV of CAD (n=6) and AVS (n=6) patients undergoing cardiac surgery. LV and RV biopsies were collected during surgery before ischemic cold blood cardioplegic arrest (pre) and 20 min after reperfusion (post). Tissues were snap frozen, proteins extracted, and the extracts were used for proteomic and phosphoproteomic analysis using Tandem Mass Tag (TMT) analysis. The results were analysed using QuickGO and Ingenuity Pathway Analysis softwares. For each comparision, our proteomic analysis identified more than 3,000 proteins which could be detected in both the pre and Post samples. Cardioplegic arrest and reperfusion were associated with significant differential expression of 24 (LV) and 120 (RV) proteins in the CAD patients, which were linked to mitochondrial function, inflammation and cardiac contraction. By contrast, AVS patients showed differential expression of only 3 LV proteins and 2 RV proteins, despite a significantly longer duration of ischaemic cardioplegic arrest. The relative expression of 41 phosphoproteins was significantly altered in CAD patients, with 18 phosphoproteins showing altered expression in AVS patients. Inflammatory pathways were implicated in the changes in phosphoprotein expression in both groups. Inter‑disease comparison for the same ventricular chamber at both timepoints revealed differences relating to inflammation and adrenergic and calcium signalling. In conclusion, the present study found that ischemic arrest and reperfusion trigger different changes in the proteomes and phosphoproteomes of LV and RV of CAD and AVS patients undergoing surgery, with markedly more changes in CAD patients despite a significantly shorter ischaemic period.

Correlation Between Cardiac Computed Tomography and Histopathology for Evaluating Patients with Aortic Valve Disease

BACKGROUND

The use of cardiac computed tomography (cardiac CT) and the quantification of the Agatston score for the evaluation of calcium of the aortic valve (AVC) has increased in different clinical contexts for diagnostic and prognostic purposes. This study aims to evaluate the correlation between cardiac CT and histopathology for the quantification of AVC.

METHODS

Ninety patients diagnosed with severe aortic valve dysfunction, of any etiology and regardless of the predominant type of injury, were included. Before the surgical event, a Cardiac CT were performed with Agatston Score measurement. The removed native valve was evaluated by a Pathologist, who provided a qualitative and quantitative evaluation of valve calcium. Calcium density was also analyzed by quantifying the area in pixel units obtained from photomicrographs. Follow-up was performed for four years after the aortic valve replacement.

RESULTS

Ninety patients were analyzed. The degenerative etiology predominated 63.3% (57 patients). The calcium load was different for the gender (p = 0.01) and type of valve injury (p = 0.0013). There was a positive correlation between the Agatston score, and the percentage of calcium reported by the pathologist in a conventional qualitative way (rs = 0.75, p < 0.001) and between the AVC and the Cote et al. score (rs = 0.77, p < 0.001). There was no difference in survival after aortic valve replacement concerning valve calcium load. Left ventricular dysfunction showed a significant difference in survival (p = 0.003, Log-rank).

CONCLUSION

There is a moderately high correlation between the Agatston score quantified by Cardiac CT and the histopathological evaluation. The severity of the calcification did not prove to be a predictor of death in the postsurgical follow-up.

Supporting the Ross procedure: preserving root physiology while mitigating autograft dilatation

PURPOSE OF REVIEW

The purpose of this article is to describe the optimized approach to nonrepairable aortic valve disease in young adults with a Ross procedure, while preserving the dynamic physiology of the aortic root.

RECENT FINDINGS

As the techniques for supporting pulmonary autografts continue to be refined, and the applicability of the Ross procedure continues to expand, an assessment of the various techniques based on aortic root physiology is warranted. Semi-resorbable scaffolds show promise in ovine models for improving the Ross procedure. Recent long-term outcomes for the Dacron inclusion technique in comparison to more physiologic methods of support emphasize the importance of balancing the prevention of early dilatation with the preservation of root haemodynamics. As this review will synthesize, the dynamic physiology of the root may be preserved even in patients at a higher risk of autograft dilatation.

SUMMARY

The favourable long-term outcomes of the Ross procedure can be partly attributed to the ability of the autograft to restore dynamism to the neoaortic root. Patient-specific modifications that respect root physiology can tailor the Ross procedure to address each patient's risk factors for early dilatation and late failure. As such, the Ross procedure should be recognized as an increasingly favourable solution for a wide spectrum of nonpreservable aortic valve disease in young adults.

Associations between aortic regurgitation severity and risk of incident myocardial infarction and stroke among patients with degenerative aortic valve disease: insights from a large Chinese population-based cohort study

OBJECTIVES

Few studies have explored whether the risk of myocardial infarction (MI) or stroke varies among patients with degenerative aortic valve disease (DAVD) with different severity of aortic regurgitation (AR) or not. Thus, a prospective study was conducted to elucidate the causal relationship between AR severity and risk of incident MI and stroke among patients with DAVD recruited from a general population in Northeast China.

DESIGN

Prospective cohort study.

SETTING

Community-based study carried out in rural areas of Northeast China.

METHODS

There were 3675 patients with DAVD aged ≥45 years eligible for the prospective study. During a median follow-up time of 4.64 years, 99 participants lost to follow-up. Cox regression analyses were used to investigate the association between baseline AR severity and the risk of incident MI or stroke.

RESULTS

In the final cohort of 3576 patients with DAVD, there were 3153 patients without AR (88.2%), 386 patients with mild AR (10.8%) and 37 patients with moderate or severe AR (1.0%). Multivariate analyses showed that, compared with participants without AR, those with moderate/severe AR were associated with 8.33 and 6.22-fold increased risk of MI and MI mortality, respectively. However, no significant associations between AR and the risk of stroke or stroke mortality were observed.

CONCLUSIONS

As compared with no AR, moderate/severe AR but not mild AR was an independent predictor for the risk of MI and MI mortality. AR was not significantly associated with stroke or stroke mortality, irrespective of AR severity. Secondary prevention strategies should be taken to delay the progression of DAVD and thus reduce the incidence of MI.

Hydrogen sulfide inhibits calcification of heart valves; implications for calcific aortic valve disease

BACKGROUND AND PURPOSE

Calcification of heart valves is a frequent pathological finding in chronic kidney disease and in elderly patients. Hydrogen sulfide (H2 S) may exert anti-calcific actions. Here we investigated H2 S as an inhibitor of valvular calcification and to identify its targets in the pathogenesis.

EXPERIMENTAL APPROACH

Effects of H2 S on osteoblastic transdifferentiation of valvular interstitial cells (VIC) isolated from samples of human aortic valves were studied using immunohistochemistry and western blots. We also assessed H2S on valvular calcification in apolipoprotein E-deficient (ApoE-/- ) mice.

KEY RESULTS

In human VIC, H2 S from donor compounds (NaSH, Na2 S, GYY4137, AP67, and AP72) inhibited mineralization/osteoblastic transdifferentiation, dose-dependently in response to phosphate. Accumulation of calcium in the extracellular matrix and expression of osteocalcin and alkaline phosphatase was also inhibited. RUNX2 was not translocated to the nucleus and phosphate uptake was decreased. Pyrophosphate generation was increased via up-regulating ENPP2 and ANK1. Lowering endogenous production of H2 S by concomitant silencing of cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS) favoured VIC calcification. analysis of human specimens revealed higher Expression of CSE in aorta stenosis valves with calcification (AS) was higher than in valves of aortic insufficiency (AI). In contrast, tissue H2 S generation was lower in AS valves compared to AI valves. Valvular calcification in ApoE-/- mice on a high-fat diet was inhibited by H2 S.

CONCLUSIONS AND IMPLICATIONS

The endogenous CSE-CBS/H2 S system exerts anti-calcification effects in heart valves providing a novel therapeutic approach to prevent hardening of valves.

LINKED ARTICLES

This article is part of a themed section on Hydrogen Sulfide in Biology & Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.4/issuetoc.