Aortic valve calcification on computed tomography predicts the severity of aortic stenosis

Aortic Valve Calcium Score by Computed Tomography as an Adjunct to Echocardiographic Assessment-A Review of Clinical Utility and Applications

Aortic valve stenosis (AS) is increasing in prevalence due to the aging population, and severe AS is associated with significant morbidity and mortality. Echocardiography remains the mainstay for the initial detection and diagnosis of AS, as well as for grading of severity. However, there are important subgroups of patients, for example, patients with low-flow low-gradient or paradoxical low-gradient AS, where quantification of severity of AS is challenging by echocardiography and underestimation of severity may delay appropriate management and impart a worse prognosis. Aortic valve calcium score by computed tomography has emerged as a useful clinical diagnostic test that is complimentary to echocardiography, particularly in cases where there may be conflicting data or clinical uncertainty about the degree of AS. In these situations, aortic valve calcium scoring may help re-stratify grading of severity and, therefore, further direct clinical management. This review presents the evolution of aortic valve calcium score by computed tomography, its diagnostic and prognostic value, as well as its utility in clinical care.

Diagnostic role of aortic valve calcium scoring in various etiologies of aortic stenosis

Most of the studies about aortic valve calcium (AVC) score in aortic stenosis (AS) were based on degenerative or bicuspid AS but not rheumatic AS. We aimed to study the diagnostic accuracy of AVC score to determine severe AS in various etiologies. Adult patients diagnosed with mild to severe AS were enrolled. AVC score were identified from multi-detector computed tomography (MDCT) scan. The AVC score was highest in bicuspid AS (3211.9 (IQR (1100.0-4562.4) AU) compared to degenerative AS (1803.7 (IQR (1073.6-2550.6) AU)), and rheumatic AS (875.6 (IQR 453.3-1594.0) AU), p < 0.001. For the ROC curve to identify severe AS, the AVC score performed well in degenerative and bicuspid AS with the area under the ROC curve (AuROC) 0.834 (95% CI, 0.730, 0.938) in degenerative group; and 0.820 (95% CI, 0.687, 0.953) in bicuspid AS. Whereas AVC score had non-significant diagnostic accuracy with AuROC 0.667 (95% CI, 0.357, 0.976) for male and 0.60(95% CI, 0.243, 0.957) for female in rheumatic AS. The cut-off AVC score values to identify severe AS were AVCS > 2028.9AU (male) and > 1082.5AU (female) for degenerative AS, and > 2431.8AU (male) and > 1293.5AU (female) for bicuspid AS. In conclusions, AVC score is the accurate test for assessing severity in patients with degenerative and bicuspid AS but performs poorly in rheumatic AS group.

3D histopathology of stenotic aortic valve cusps using ex vivo microfocus computed tomography

Background

Calcific aortic stenosis (AS) is the most prevalent heart valve disease in developed countries. The aortic valve cusps progressively thicken and the valve does not open fully due to the presence of calcifications. In vivo imaging, usually used for diagnosis, does not allow the visualization of the microstructural changes associated with AS.

Methods

Ex vivo high-resolution microfocus computed tomography (microCT) was used to quantitatively describe the microstructure of calcified aortic valve cusps in full 3D. As case study in our work, this quantitative analysis was applied to normal-flow low-gradient severe AS (NF-LG-SAS), for which the medical prognostic is still highly debated in the current literature, and high-gradient severe AS (HG-SAS).

Results

The volume proportion of calcification, the size and number of calcified particles and their density composition was quantified. A new size-based classification considering small-sized particles that are not detected with in vivo imaging was defined for macro-, meso- and microscale calcifications. Volume and thickness of aortic valve cusps, including the complete thickness distribution, were also determined. Moreover, changes in the cusp soft tissues were also visualized with microCT and confirmed by scanning electron microscopy images of the same sample. NF-LG-SAS cusps contained lower relative amount of calcifications than HG-SAS. Moreover, the number and size of calcified objects and the volume and thickness of the cusps were also lower in NF-LG-SAS cusps than in HG-SAS.

Conclusions

The application of high-resolution ex vivo microCT to stenotic aortic valve cusps provided a quantitative description of the general structure of the cusps and of the calcifications present in the cusp soft tissues. This detailed description could help in the future to better understand the mechanisms of AS.

Aortic stenosis: a review on acquired pathogenesis and ominous combination with diabetes mellitus

BACKGROUND

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 progression from mild to severe. The interplay between AS and DM's mechanism is not entirely known yet.

MAIN BODY

The increased accumulation of advanced glycation end products (AGEs) was linked to increased valvular oxidative stress, inflammation, expression of coagulation factors, and signs of calcification, according to an analysis of aortic stenotic valves. It is interesting to note that in diabetic AS patients, valvular inflammation did not correlate with serum glucose levels but rather only with long-term glycemic management markers like glycated haemoglobin and fructosamine. Transcatheter aortic valve replacement, which has been shown to be safer than surgical aortic valve replacement, is advantageous for AS patients who also have concurrent diabetes. Additionally, novel anti-diabetic medications have been proposed to lower the risk of AS development in DM patients, including sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonist that target reduction of AGEs-mediated oxidative stress.

CONCLUSIONS

There are little data on the effects of hyperglycemia on valvular calcification, but understanding the interactions between them is essential to develop a successful treatment strategy to stop or at least slow the progression of AS in DM patients. There is a link among AS and DM and that DM negatively impacts the quality of life and longevity of AS patients. The sole successful treatment, despite ongoing efforts to find new therapeutic modalities, involves aortic valve replacement. More research is required to find methods that can slow the advancement of these conditions, enhancing the prognosis and course of people with AS and DM.

Models and Techniques to Study Aortic Valve Calcification in Vitro, ex Vivo and in Vivo. An Overview

Aortic valve stenosis secondary to aortic valve calcification is the most common valve disease in the Western world. Calcification is a result of pathological proliferation and osteogenic differentiation of resident valve interstitial cells. To develop non-surgical treatments, the molecular and cellular mechanisms of pathological calcification must be revealed. In the current overview, we present methods for evaluation of calcification in different ex vivo, in vitro and in vivo situations including imaging in patients. The latter include echocardiography, scanning with computed tomography and magnetic resonance imaging. Particular emphasis is on translational studies of calcific aortic valve stenosis with a special focus on cell culture using human primary cell cultures. Such models are widely used and suitable for screening of drugs against calcification. Animal models are presented, but there is no animal model that faithfully mimics human calcific aortic valve disease. A model of experimentally induced calcification in whole porcine aortic valve leaflets ex vivo is also included. Finally, miscellaneous methods and aspects of aortic valve calcification, such as, for instance, biomarkers are presented.

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.

Radiologist opinions regarding reporting incidental coronary and cardiac calcification on thoracic CT

Objectives

Coronary and cardiac calcification are frequent incidental findings on non-gated thoracic computed tomography (CT). However, radiologist opinions and practices regarding the reporting of incidental calcification are poorly understood.

Methods

UK radiologists were invited to complete this online survey, organised by the British Society of Cardiovascular Imaging (BSCI). Questions included anonymous information on subspecialty, level of training and reporting practices for incidental coronary artery, aortic valve, mitral and thoracic aorta calcification.

Results

The survey was completed by 200 respondents: 10% trainees and 90% consultants. Calcification was not reported by 11% for the coronary arteries, 22% for the aortic valve, 35% for the mitral valve and 37% for the thoracic aorta. Those who did not subspecialise in cardiac imaging were less likely to report coronary artery calcification (p = 0.005), aortic valve calcification (p = 0.001) or mitral valve calcification (p = 0.008), but there was no difference in the reporting of thoracic aorta calcification. Those who did not subspecialise in cardiac imaging were also less likely to provide management recommendations for coronary artery calcification (p < 0.001) or recommend echocardiography for aortic valve calcification (p < 0.001), but there was no difference for mitral valve or thoracic aorta recommendations.

Conclusion

Incidental coronary artery, valvular and aorta calcification are frequently not reported on thoracic CT and there are differences in reporting practices based on subspeciality.

Advances in knowledge

On routine thoracic CT, 11% of radiologists do not report coronary artery calcification. Radiologist reporting practices vary depending on subspeciality but not level of training.

Lipoprotein(a) and aortic valve stenosis: A casual or causal association?

AIMS

This review aims to provide an update of available methods for imaging calcification activity and potential therapeutic options.

DATA SYNTHESIS

Aortic valve calcification represents the most common heart valve condition requiring treatment among adults in Western societies. No medical therapies are proven to be effective in treating symptoms or reducing disease progression. Therefore, surgical or transcatheter aortic valve replacement remains the only available treatment option. Elevated circulating concentrations of lipoprotein(a) is strongly associated with degenerative aortic stenosis. This relationship was first observed in prospective observational studies, and the causal relationship was confirmed in genetic studies.

CONCLUSIONS

New therapeutic targets have been identified and new imaging techniques could be used to test the effectiveness of new agents and further clarify the pathophysiology of AVS. No therapy that specifically lowers Lp (a) levels has been approved for clinical use.

Imaging Challenges in Patients with Severe Aortic Stenosis and Heart Failure: Did We Find a Way Out of the Labyrinth?

Aortic stenosis (AS) is the most frequent degenerative valvular disease in developed countries. Its incidence has been constantly rising due to population aging. The diagnosis of AS was considered straightforward for a very long time. High gradients and reduced aortic valve area were considered as "sine qua non" in diagnosis of AS until a growing body of evidence showed that patients with low gradients could also have severe AS with the same or even worse outcome. This completely changed the paradigm of AS diagnosis and involved large numbers of parameters that had never been used in the evaluation of AS severity. Low gradient AS patients may present with heart failure (HF) with preserved or reduced left ventricular ejection fraction (LVEF), associated with changes in cardiac output and flow across the aortic valve. These patients with low-flow low-gradient or paradoxical low-flow low-gradient AS are particularly challenging to diagnose, and cardiac output and flow across the aortic valve have become the most relevant parameters in evaluation of AS, besides gradients and aortic valve area. The introduction of other imaging modalities in the diagnosis of AS significantly improved our knowledge about cardiac mechanics, tissue characterization of myocardium, calcium and inflammation burden of the aortic valve, and their impact on severity, progression and prognosis of AS, not only in symptomatic but also in asymptomatic patients. However, a variety of novel parameters also brought uncertainty regarding the clinical relevance of these indices, as well as the necessity for their validation in everyday practice. The aim of this review is to summarize the prevalence of HF in patients with severe AS and elaborate on the diagnostic challenges and advantages of comprehensive multimodality cardiac imaging to identify the patients that may benefit from surgical or transcatheter aortic valve replacement, as well as parameters that may help during follow-up.

Aortic valve calcification among elderly males from the general population, associated echocardiographic findings, and clinical implications

AIMS

Aortic valve calcification (AVC) detected by non-contrast computed tomography (NCCT) associates with morbidity and mortality in patients with aortic valve stenosis. However, the importance of AVC in the general population is sparsely evaluated. We intend to describe the associations between AVC score on NCCT and echocardiographic findings as left atrial (LA) dilatation, left ventricular (LV) hypertrophy, aortic valve area (AVA), peak velocity, mean gradient, and aortic valve replacement (AVR) in a population with AVC scores ≥300 AU.

METHODS AND RESULTS

Of 10 471 males aged 65-74 years from the Danish Cardiovascular Screening trial (DANCAVAS), participants with AVC score ≥300 AU were invited for transthoracic echocardiography and 828 (77%) of 1075 accepted the invitation. AVC scores were categorized (300-599, 600-799, 800-1199, and ≥1200 AU). AVR was obtained from registries. AVC was significantly associated with a steady increase in LA dilation (10.5%, 16.3%, 15.8%, 19.6%, P = 0.031), LV hypertrophy (3.9%, 6.6%, 8.9%, 10.1%, P = 0.021), peak velocity (1.7, 1.9, 2.1, 2.8 m/s, P = 0001), mean gradient (6, 8, 11, 19 mmHg, P = 0.0001), and a decrease in AVA (2.0, 1.9, 1.7, 1.3 cm2, P = 0.0001). The area under the curve was 0.79, 0.93, and 0.92 for AVA ≤1.5 cm2, peak velocity ≥3.0 m/s, and mean gradient ≥20 mmHg, respectively, and the associated optimal AVC score thresholds were 734, 1081, and 1019 AU. AVC > 1200 AU was associated with AVR (P < 0.0001).

CONCLUSION

Among males from the background population, increasing AVC scores were associated with LA dilatation, LV hypertrophy, AVA, peak aortic velocity, mean aortic gradient, and AVR.

Sex differences in aortic valve calcification in severe aortic valve stenosis: association between computer tomography assessed calcification and valvular calcium concentrations

AIMS

The aims of this study were to investigate the correlation and sex differences between total valve calcium, valve calcium concentration, and aortic valve calcification (AVC) in explanted valves from patients with severe aortic valve stenosis undergoing aortic valve replacement (AVR).

METHODS AND RESULTS

Sixty-nine patients with severe aortic stenosis (AS) scheduled for elective AVR underwent echocardiography and cardiac computed tomography (CT) prior to surgery (AVCin vivo) and CT of the explanted aortic valve (AVCex vivo). Explanted valves were prepared in acid solution, sonicated, and analysed with Arsenazo III dye to estimate total valve calcium and valve calcium concentration. Median AVCex vivo was 2082 (1421-2973) AU; mean valve calcium concentration was 1.43 ± 0.42 µmol Ca2+/mg tissue; median total valve calcium 156 (111-255) mg Ca2+, and valve calcium density 52 (35-81) mg/cm2. AVC displayed a strong correlation with total valve calcium (R2 = 0.98, P < 0.001) and a moderate correlation with valve calcium concentration (R2 = 0.62, P < 0.001). Valvular calcium concentration was associated with sex, aortic valve area, and mean gradient. After adjusting for age and estimated glomerular filtration rate, sex and mean gradient remained associated with valve calcium concentrations.

CONCLUSION

AVC score provides a strong estimate for total valve calcium but to a lesser degree calcium concentration in the valve tissue of patients with severe AS. Females presented lower valvular calcium concentrations than males irrespective of AS severity, adding evidence and providing support to the important point that sex differences in valvular calcium concentration in AS does not reflect valvular size.

Diagnostic and Prognostic Performance of Aortic Valve Calcium Score with Cardiac CT for Aortic Stenosis: A Meta-Analysis

PURPOSE

To evaluate the diagnostic and prognostic performance of the aortic valve calcium score (AVCS) with the Agatston method using CT in aortic stenosis (AS) and to assess mean AVCS according to AS severity.

MATERIALS AND METHODS

In this meta-analysis, PubMed, Embase, and Cochrane were searched from January 1, 1980, to December 31, 2020, for studies reporting sensitivity and specificity of AVCS using CT for severe AS, mean AVCS in severe and nonsevere AS, and/or hazard ratios for all-cause mortality in AS. Data were pooled using random effect models and meta-analysis software.

RESULTS

Twelve studies (six diagnostic, three prognostic, and 10 reporting mean AVCS by AS severity) were included for analysis. A total of 4101 patients (2255 with severe AS) were described in these 12 studies. Pooled sensitivity and specificity were 82% (95% CI: 80, 84) and 78% (95% CI: 75, 81), respectively. Pooled mean AVCS were 3219 (95% CI: 2795, 3643) for severe AS, compared with 1252 (95% CI: 863, 1640) for nonsevere AS, 1808 (95% CI: 1163, 2452) for moderate AS, and 584 (95% CI: 309, 859) for mild AS. Pooled hazard ratio for AVCS as a binary threshold to predict mortality was 2.11 (95% CI: 1.11, 4.12).

CONCLUSION

AVCS had moderate to high sensitivity and specificity for identifying severe AS and was also a useful prognostic imaging marker in AS. Mean AVCS categorized by AS severity may help guide clinical management.Keywords CT, Aortic Valve, Valves, Meta-Analysis© RSNA, 2021.

Dissecting Calcific Aortic Valve Disease-The Role, Etiology, and Drivers of Valvular Fibrosis

Calcific aortic valve disease (CAVD) is a highly prevalent and progressive disorder that ultimately causes gradual narrowing of the left ventricular outflow orifice with ensuing devastating hemodynamic effects on the heart. Calcific mineral accumulation is the hallmark pathology defining this process; however, fibrotic extracellular matrix (ECM) remodeling that leads to extensive deposition of fibrous connective tissue and distortion of the valvular microarchitecture similarly has major biomechanical and functional consequences for heart valve function. Significant advances have been made to unravel the complex mechanisms that govern these active, cell-mediated processes, yet the interplay between fibrosis and calcification and the individual contribution to progressive extracellular matrix stiffening require further clarification. Specifically, we discuss (1) the valvular biomechanics and layered ECM composition, (2) patterns in the cellular contribution, temporal onset, and risk factors for valvular fibrosis, (3) imaging valvular fibrosis, (4) biomechanical implications of valvular fibrosis, and (5) molecular mechanisms promoting fibrotic tissue remodeling and the possibility of reverse remodeling. This review explores our current understanding of the cellular and molecular drivers of fibrogenesis and the pathophysiological role of fibrosis in CAVD.

Prevalence and clinical implications of valvular calcification on coronary computed tomography angiography

AIMS

Valvular heart disease can be identified by calcification on coronary computed tomography angiography (CCTA) and has been associated with adverse clinical outcomes. We assessed aortic and mitral valve calcification in patients presenting with stable chest pain and their association with cardiovascular risk factors, coronary artery disease, and cardiovascular outcomes.

METHODS AND RESULTS

In 1769 patients (58 ± 9 years, 56% male) undergoing CCTA for stable chest pain, aortic and mitral valve calcification were quantified using Agatston score. Aortic valve calcification was present in 241 (14%) and mitral calcification in 64 (4%). Independent predictors of aortic valve calcification were age, male sex, hypertension, diabetes mellitus, and cerebrovascular disease, whereas the only predictor of mitral valve calcification was age. Patients with aortic and mitral valve calcification had higher coronary artery calcium scores and more obstructive coronary artery disease. The composite endpoint of cardiovascular mortality, non-fatal myocardial infarction, or non-fatal stroke was higher in those with aortic [hazard ratio (HR) 2.87; 95% confidence interval (CI) 1.60-5.17; P < 0.001] or mitral (HR 3.50; 95% CI 1.47-8.07; P = 0.004) valve calcification, but this was not independent of coronary artery calcification or obstructive coronary artery disease.

CONCLUSION

Aortic and mitral valve calcification occurs in one in six patients with stable chest pain undergoing CCTA and is associated with concomitant coronary atherosclerosis. Whilst valvular calcification is associated with a higher risk of cardiovascular events, this was not independent of the burden of coronary artery disease.

Effect of the 2017 European Guidelines on Reclassification of Severe Aortic Stenosis and Its Influence on Management Decisions for Initially Asymptomatic Aortic Stenosis

BACKGROUND

The 2017 European Society of Cardiology guidelines for valvular heart disease included changes in the definition of severe aortic stenosis (AS). We wanted to evaluate its influence on management decisions in asymptomatic patients with moderate-severe AS.

METHODS

We reclassified the AS severity of the participants of the PRIMID-AS study (Prognostic Importance of Microvascular Dysfunction in Asymptomatic Patients With AS), using the 2017 guidelines, determined their risk of reaching a clinical end point (valve replacement for symptoms, hospitalization, or cardiovascular death) and evaluated the prognostic value of aortic valve calcium score and biomarkers. Patients underwent echocardiography, cardiac magnetic resonance imaging, exercise tolerance testing, and biomarker assessment.

RESULTS

Of the 174 participants, 45% (56/124) classified as severe AS were reclassified as moderate AS. This reclassified group was similar to the original moderate group in clinical characteristics, gradients, calcium scores, and remodeling parameters. There were 47 primary end points (41 valve replacement, 1 death, and 5 hospitalizations-1 chest pain, 2 dyspnea, 1 heart failure, and 1 syncope) over 368±156 days follow-up. The severe and reclassified groups had a higher risk compared with moderate group (adjusted hazard ratio 4.95 [2.02-12.13] and 2.78 [1.07-7.22], respectively), with the reclassified group demonstrating an intermediate risk. A mean pressure gradient ≥31 mm Hg had a 7× higher risk of the primary end point in the reclassified group. Aortic valve calcium score was more prognostic in females and low valve area but not after adjusting for gradients. NT-proBNP (N-terminal pro-brain-type natriuretic peptide) and myocardial perfusion reserve were associated with the primary end point but not after adjusting for positive exercise tolerance testing. Troponin was associated with cardiovascular death or unplanned hospitalizations.

CONCLUSIONS

Reclassification of asymptomatic severe AS into moderate AS was common using the European Society of Cardiology 2017 guidelines. This group had an intermediate risk of reaching the primary end point. Exercise testing, multimodality imaging, and lower mean pressure gradient threshold of 31 mm Hg may improve risk stratification. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01658345.

Reporting incidental coronary, aortic valve and cardiac calcification on non-gated thoracic computed tomography, a consensus statement from the BSCI/BSCCT and BSTI

Incidental coronary and cardiac calcification are frequent findings on non-gated thoracic CT. We recommend that the heart is reviewed on all CT scans where it is visualised. Coronary artery calcification is a marker of coronary artery disease and it is associated with an adverse prognosis on dedicated cardiac imaging and on non-gated thoracic CT performed for non-cardiac indications, both with and without contrast. We recommend that coronary artery calcification is reported on all non-gated thoracic CT using a simple patient-based score (none, mild, moderate, severe). Furthermore, we recommend that reports include recommendations for subsequent management, namely the assessment of modifiable cardiovascular risk factors and, if the patient has chest pain, assessment as per standard guidelines. In most cases, this will not necessitate additional investigations. Incidental aortic valve calcification may also be identified on non-gated thoracic CT and should be reported, along with ancillary findings such as aortic root dilation. Calcification may occur in other parts of the heart including mitral valve/annulus, pericardium and myocardium, but in many cases these are an incidental finding without clinical significance.

Cardiovascular imaging modalities in the diagnosis and management of rheumatic heart disease

Rheumatic heart disease (RHD) is prevalent in sub-Saharan Africa, where the capacity for diagnosis and evaluation of disease severity and complications is not always optimal. While the medical history and physical examination are important in the assessment of patients suspected to have RHD, cardiovascular imaging techniques are useful for confirmation of the diagnosis. Echocardiography is the workhorse modality for initial evaluation and diagnosis of RHD. Cardiovascular magnetic resonance is complementary and may provide additive information, including tissue characteristics, where echocardiography is inadequate or non-diagnostic. There is emerging evidence on the role of computed tomography, particularly following valve replacement surgery, in the monitoring and management of RHD. This article summarises the techniques used in imaging RHD patients, considers the evidence base for their utility, discusses their limitations and recognises the clinical contexts in which indications and imaging with various modalities are expanding.

Aortic valve stenosis-multimodality assessment with PET/CT and PET/MRI

Aortic valve disease is the most common form of heart valve disease in developed countries and a growing healthcare burden with an ageing population. Transthoracic and transoesophageal echocardiography remains central to the diagnosis and surveillance of patients with aortic stenosis, providing gold standard assessments of valve haemodynamics and myocardial performance. However, other multimodality imaging techniques are being explored for the assessment of aortic stenosis, including combined PET/CT and PET/MR. Both approaches provide unique information with respect to disease activity in the valve alongside more conventional anatomic assessments of the valve and myocardium in this condition. This review investigates the emerging use of PET/CT and PET/MR to assess patients with aortic stenosis, examining how the complementary data provided by each modality may be used for research applications and potentially in future clinical practice.

Sex-specific differences in age-related aortic valve calcium load: A systematic review and meta-analysis

Aging of the aortic valve, characterized by leaflet thickening and loss of extensibility, leads to progressive changes in valve function. These age-related mechanisms have not been evaluated yet in sex-specific calcific aortic valve stenosis (CAVS) onset and progression. Recent studies reported the association between high aortic valve calcification (AVC) load and male gender in patients with CAVS while women present faster progression than men. To evaluate these age- and sex-specific differences, we performed a systematic review and meta-analysis with meta-regression. A systematic search related to AVC measured by computed tomography and gender-specific differences was conducted according to PRISMA guidelines. Seven studies, enrolling 1859 men and 1055 women, were included in the quantitative synthesis. We found a significant difference between men and women both in AVC load and density. AVC load mean difference (MD), between men and women, was 1131 ± 243 AU (p < 0.0001; I²: 96.5 %, p < 0.001), while AVC density MD was 159 ± 20 AU/cm² (p < 0.0001) without heterogeneity among the studies (I²: 23.5, p = 0.3). Meta-regression analyses showed that AVC load MD positively correlated with age and other cardiovascular risk factors such as diabetes, hypertension, and coronary artery disease presence. Our meta-analysis shows a significant association of incremental AVC load with male gender, regardless of the individual anatomical characteristics and the cardiovascular risk factors. Further studies are needed: i) to clarify if there are different sex-related pathophysiological processes driving the development and the progression of age-related CAVS, and ii) to determine if a sex-specific therapeutic strategy should be applied for CAVS treatment and/or prevention.

Precision and Personalized Medicine: How Genomic Approach Improves the Management of Cardiovascular and Neurodegenerative Disease

Life expectancy has gradually grown over the last century. This has deeply affected healthcare costs, since the growth of an aging population is correlated to the increasing burden of chronic diseases. This represents the interesting challenge of how to manage patients with chronic diseases in order to improve health care budgets. Effective primary prevention could represent a promising route. To this end, precision, together with personalized medicine, are useful instruments in order to investigate pathological processes before the appearance of clinical symptoms and to guide physicians to choose a targeted therapy to manage the patient. Cardiovascular and neurodegenerative diseases represent suitable models for taking full advantage of precision medicine technologies applied to all stages of disease development. The availability of high technology incorporating artificial intelligence and advancement progress made in the field of biomedical research have been substantial to understand how genes, epigenetic modifications, aging, nutrition, drugs, microbiome and other environmental factors can impact health and chronic disorders. The aim of the present review is to address how precision and personalized medicine can bring greater clarity to the clinical and biological complexity of these types of disorders associated with high mortality, involving tremendous health care costs, by describing in detail the methods that can be applied. This might offer precious tools for preventive strategies and possible clues on the evolution of the disease and could help in predicting morbidity, mortality and detecting chronic disease indicators much earlier in the disease course. This, of course, will have a major effect on both improving the quality of care and quality of life of the patients and reducing time efforts and healthcare costs.

Genetic and In Vitro Inhibition of PCSK9 and Calcific Aortic Valve Stenosis

The authors investigated whether PCSK9 inhibition could represent a therapeutic strategy in calcific aortic valve stenosis (CAVS). A meta-analysis of 10 studies was performed to determine the impact of the PCSK9 R46L variant on CAVS, and the authors found that CAVS was less prevalent in carriers of this variant (odds ratio: 0.80 [95% confidence interval: 0.70 to 0.91]; p = 0.0011) compared with noncarriers. PCSK9 expression was higher in the aortic valves of patients CAVS compared with control patients. In human valve interstitials cells submitted to a pro-osteogenic medium, PCSK9 levels increased and a PCSK9 neutralizing antibody significantly reduced calcium accumulation.

Imaging diagnosis of aortic stenosis

Aortic valve stenosis (AS) is the commonest primary valve disorder with increasing prevalence with age. Trans-thoracic echocardiogram is the main imaging technique used to diagnose AS, but discrepancy in diagnosis has been described in almost one third of cases. Other imaging methods, particularly electrocardiogram (ECG)-gated computed tomography, have now emerged to further clarify the diagnosis of AS by both demonstrating the degree of calcification in the valve as well as aortic valve area. Cardiac magnetic resonance imaging allows accurate quantification of ventricular function and evaluation of the myocardium. This paper provides a comprehensive review of the diagnosis of AS for the radiologist.

Imaging aortic valve calcification: significance, approach and implications

Aortic stenosis is the most prevalent valvular heart disease worldwide, and rates are increasing with the growing and more elderly population. Although the precise mechanisms that underpin aortic valve stenosis are incompletely understood, pathological valvular calcification has emerged as a key instigator in mediating the biomechanical stiffening that can lead to symptoms, the need for aortic valve replacement, and death if left untreated. Here, we review the currently understood processes leading to aortic valve calcification, summarise the contemporary imaging assessments of valve calcification, and highlight how these might improve patient care and accelerate our pathological understanding and the development of an effective medical therapy.

Bench to bedside defining calcific aortic valve disease: osteocardiology

INTRODUCTION

For years, calcific aortic valve disease (CAVD) was thought to be due to a degenerative process, but recent scientific discoveries have proven it to be an active process. Understanding the cellular mechanisms for the development of disease and translating the cellular changes critical in the development of calcific phenotypes. The use of multimodality imaging has been the gold standard to define the development of calcification to determine the timing of therapy.

AREAS COVERED

This review will discuss the scientific literature in a new and evolving field known as osteocardiology, which specifically defines the cellular mechanisms involved in the development of the osteogenic phenotype in the heart and vasculature. The work in this field has been highlighted by the calcific aortic valve disease working group at the NIH. This review will discuss the appropriate use criteria for multimodality imaging techniques to identify early cellular and hemodynamic disease progression in the aortic valve to help determine the timing of therapy, the osteocardiology theory.

EXPERT OPINION

The authors will provide their background in basic science and clinical medicine to support the opinions in this paper.

Visual scoring of aortic valve calcifications on low-dose CT in lung cancer screening

OBJECTIVES

To evaluate risk factors for prevalence and progression of aortic valve calcification (AVC) in lung cancer screening participants and also to assess the sensitivity and reliability of visual AVCs on low-dose CT (LDCT) for predicting aortic stenosis (AS) in high-risk smokers.

METHODS

We reviewed 1225 consecutive participants in annual LDCT screening for lung cancer at the Mount Sinai Hospital between 2010 and 2017. Sensitivity and specificity of moderate/severe AVC score on LDCT to identify AS on echocardiogram were calculated for 126 participants who had both within 12 months. Using regression analyses, risk factors for AVC at baseline, for progression, and for new AVC on annual rounds of screening were identified. Reliability of AVC assessment on LDCT was assessed by comparing visual AVC scores (1) with standard-dose, electrocardiography (ECG)-gated CT for 31 participants who had both within 12 months and (2) with Agatston scores of 1225 participants and by determining (3) the intra-reader agreement of 1225 participants.

RESULTS

Visual AVC scores on LDCT had substantial agreement with the severity of AS on echocardiography and substantial inter-observer and excellent intra-observer agreement. Sensitivity and specificity of moderate/severe visual AVC scores for moderate/severe AS on echocardiogram were 100% and 94%, respectively. Significant predictors for baseline AVC were male sex (OR = 2.52), age (OR_{10 years} = 2.87), and coronary artery calcification score (OR = 1.18), the significant predictor for AVC progression after baseline was pack-years of smoking (HR_{10 packyears} = 1.14), and significant predictors for new AVC on annual LDCT were male sex (HR = 1.51), age (HR_{10 years} = 2.17), CAC (HR = 1.09)  and BMI (HR = 1.06).

CONCLUSIONS

AVC scores on LDCT should be documented, especially in lung cancer screening program.

KEY POINTS

• LDCT screening for lung cancer provides an opportunity to identify lung cancer and cardiovascular disease in asymptomatic smokers. • Visual aortic valve calcification scores could be reliably evaluated on LDCT and had substantial agreement with the severity of aortic valve stenosis on echocardiography. • Sensitivity and specificity of moderate/severe visual AVC scores on LDCT for moderate/severe AS on echocardiogram were 100% and 94%, respectively.

Clinical Value of Cardiovascular Calcifications on Non-Enhanced, Non-ECG-Gated Chest CT

심혈관계 석회화는 다양한 심혈관계 질환에서 나타나며 심혈관 사건 발생의 표지자의 역할을 한다. CT의 기술이 발전함에 따라 심전도동기 CT뿐만이 아닌 비 심전도동기 CT에서도 심혈관계 석회화를 평가하는 것이 가능해졌다. 이번 종설에서는 비 조영증강 비 심전도동기 흉부 CT에서 발견되는 심혈관계 석회화를 심혈관 사건 발생과 연관되었다고 알려진 3가지 석회화(관상동맥, 흉부 대동맥, 판막 석회화)에 대해 자세히 살펴보고 추가적으로 우연적으로 발견될 수 있는 심막 석회화에 대해서도 간단히 기술하였다. 우리나라에서 2019년 하반기부터 폐암 검진이 시작되면서 고령 흡연자의 비 조영증강 비 심전도동기 저선량 CT의 영상의 수가 늘어나고 있고 이에 우연히 발견되는 심혈관계 석회화도 늘어나고 있다. 그러므로 비 조영증강 비 심전도동기 흉부 CT에서 발견되는 심혈관계 석회화의 의미를 이해하고 적절히 보고하는 것이 영상의학과 의사에게 중요할 것이다.

Association between aortic valvular calcification and characteristics of the aortic valve in patients with bicuspid aortic valve stenosis

BACKGROUND

Aortic valve calcification quantification using cardiac computed tomography (CCT) is a reliable marker for aortic stenosis (AS) in patients with bicuspid aortic valve (BAV) disease.

PURPOSE

To determine the association of Agatston aortic valve calcium score (AVCS) with morphological and hemodynamic characteristics of BAV and define cut-off AVCS for optimizing the grade of AS in patients with bicuspid AS.

MATERIAL AND METHODS

This study included 161 BAV patients with AS regardless of aortic regurgitation who underwent transthoracic echocardiography and CCT. BAVs were classified according to orientation of cusps and presence of raphe. Associations of AVCS with characteristics of BAV morphology and functional variables were determined by linear regression analysis. Area under the receiver operating characteristic curve (AUC) was used to determine the cut-off AVCS greater than which the diagnosis of severe AS was optimized.

RESULTS

AVCS was significantly different according to sex ( P < 0.001), AS severity ( P < 0.001), type of valvular dysfunction ( P = 0.011), and orientation of cusps ( P = 0.028). Multiple linear regression showed that AVCS was significantly associated with sex (estimate = -0.583, P < 0.001) and AS severity (estimate = 0.817, P < 0.001). AVCS was a predictor for severe AS with AUC of 0.80 in both women ( P = 0.002) and men ( P < 0.001). Its cut-off value was 1423 Agatston unit (AU) in women and 2573 AU in men.

CONCLUSIONS

In patients with bicuspid AS, AVCS was significantly higher in men and those with severe AS. However, AVCS was not significantly associated with morphological characteristics of BAV or the type of valvular dysfunction.

Predicting Disease Progression and Mortality in Aortic Stenosis: A Systematic Review of Imaging Biomarkers and Meta-Analysis

Background: Detecting among patients with aortic stenosis (AS) those who are likely to rapidly progress, yet potentially benefiting from prophylactic aortic valve replacement, is needed for improved patient care. The objective of this study was to evaluate the role of imaging biomarkers in predicting the progression to clinical symptoms and death in patients with AS. Methods: We searched the Pubmed and the International Clinical Trials Registry Platform databases for studies including patients with AS, and investigating imaging techniques, published in any language until Jan 1, 2018. Eligible sets of data include effect of imaging biomarkers relative to: (1) Overall mortality, (2) Cardiac mortality, and (3) Overall events (Symptom onset and Major Adverse Cardiovascular Events). Meta-analysis was used to examine associations between the imaging biomarkers and outcomes of AS using Random Effect models. Results: Eight studies and 1,639 patients were included after systematic review. Four studies investigated aortic valve calcification (AVC) whereas the remaining investigated biomarkers provided by cardiac magnetic resonance (CMR). Four articles investigated the presence of midwall fibrosis on late-gadolinium enhancement imaging, three reported its extent (LGE%) and two, the myocardial extracellular volume (ECV). By decreasing strength of association, there were significant associations between cardiac mortality and LGE% [Relative Risk (RR) = 1.05, 95% Confidence Interval (CI) 1.01-1.10]; overall mortality and AVC (RR = 1.19, 95%CI: 1.05-1.36); overall events and ECV (RR = 1.68, 95%CI: 1.17-2.41); cardiac mortality and midwall fibrosis (RR = 2.88, 95%CI: 1.12-7.39). Conclusion: AVC and myocardial fibrosis imaging biomarkers predict the outcomes in AS, and help understanding AS pathophysiology and setting therapeutic targets.

Calcific aortic valve stenosis: hard disease in the heart: A biomolecular approach towards diagnosis and treatment

Calcific aortic valve stenosis (CAVS) is common in the ageing population and set to become an increasing economic and health burden. Once present, it inevitably progresses and has a poor prognosis in symptomatic patients. No medical therapies are proven to be effective in holding or reducing disease progression. Therefore, aortic valve replacement remains the only available treatment option. Improved knowledge of the mechanisms underlying disease progression has provided us with insights that CAVS is not a passive disease. Rather, CAVS is regulated by numerous mechanisms with a key role for calcification. Aortic valve calcification (AVC) is actively regulated involving cellular and humoral factors that may offer targets for diagnosis and intervention. The discovery that the vitamin K-dependent proteins are involved in the inhibition of AVC has boosted our mechanistic understanding of this process and has opened up novel avenues in disease exploration. This review discusses processes involved in CAVS progression, with an emphasis on recent insights into calcification, methods for imaging calcification activity, and potential therapeutic options.

Osteocardiology: Defining the Go/No-Go Time Point for Therapy

Recent epidemiological studies have revealed that the risk factors associated with coronary artery calcification (CAC), including male gender, smoking, hypertension, and elevated serum cholesterol, are similar to the risk factors associated with the development of calcific aortic valve disease (CAVD). The results of the experimental and clinical studies demonstrate that traditional risk factors initiate early atherosclerosis which over time differentiates to form bone in the heart causing clinical CAC and CAVD. Understanding the cellular mechanisms of cardiovascular calcification, the end-stage process of the atherosclerosis will help define the specific time point to modify this cellular process of bone formation in the heart termed osteocardiology. This time point between subclinical atherosclerosis and clinical calcification is the go/no-go time point, or the point of no return with severe clinical calcification in the heart. This review will summarize the development of bone formation in the heart termed osteocardiology, to define the go/no-go time point for therapy initiation to slow the progression of cardiovascular calcification.

New considerations in the assessment of aortic stenosis

Calcific aortic stenosis (AS) is one of the most common acquired valvular heart diseases in industrialized nations. It is a slowly progressive disease and with the aging population, the prevalence of AS is expected to increase. Doppler echocardiography is used to classify patients based on severity of stenosis. Research efforts on how to better identify and risk-assess these patients are currently underway using advanced imaging modalities and serum biomarkers. Thus far, medications for AS prevention have been unsuccessful. As technology progresses, the assessment of AS will transition from one heavily weighed on echocardiographic gradients to one of active surveillances with multimodality imaging, serum biomarkers and genetic assessment.

Valve Calcification in Aortic Stenosis: Etiology and Diagnostic Imaging Techniques

Aortic stenosis is the most common valvulopathy in the Western world. Its prevalence has increased significantly in recent years due to population aging; hence, up to 8% of westerners above the age of 84 now have severe aortic stenosis (Lindroos et al., 1993). This causes increased morbidity and mortality and therein lies the importance of adequate diagnosis and stratification of the degree of severity which allows planning the best therapeutic option in each case. Long understood as a passive age-related degenerative process, it is now considered a rather more complex entity involving mechanisms and factors similar to those of atherosclerosis (Stewart et al., 1997). In this review, we summarize the pathophysiological mechanisms underlying the onset and progression of the disease and analyze the current role of cardiac imaging techniques for diagnosis.

Pathophysiology of Aortic Valve Stenosis: Is It Both Fibrocalcific and Sex Specific?

Our understanding of the fundamental biology and identification of efficacious therapeutic targets in aortic valve stenosis has lagged far behind the fields of atherosclerosis and heart failure. In this review, we highlight the most clinically relevant problems facing men and women with fibrocalcific aortic valve stenosis, discuss the fundamental biology underlying valve calcification and fibrosis, and identify key molecular points of intersection with sex hormone signaling.

Severe and Asymptomatic Aortic Stenosis Management Challenge: Knowing That We Do Not Really Know

OPINION STATEMENT

The clinical management of asymptomatic patients with severe aortic valve stenosis (AS) may be challenging. Indeed, there is substantial controversy over the optimal timing of intervention for these patients, as some advocate early intervention while others urge for a conservative management until symptom onset. In the meantime of randomized clinical trials aiming to compare both strategies of management, an integrative approach including several imaging modalities as well as biomarkers of the myocardial damage may help to improve the risk stratification of patients with asymptomatic severe AS and individualize strategy of treatment. The extent of aortic valve calcification, semi-quantitatively assessed by echocardiography but better fully quantitatively measured by computed tomography (CT), provides incremental value to predict rapid disease progression and adverse event and thus could be a potential trigger for early referral to intervention or guide the timing of clinical follow-up. In addition, the assessment of disease activity using positron emission tomography, combined with CT calcium scoring, may also help to better predict the disease progression. The comprehensive assessment of left ventricular (LV) function using speckle-tracking echocardiography and/or cardiac magnetic resonance may provide useful information regarding the actual repercussion of AS on the myocardium. Besides imaging modalities, the measurement of several circulating biomarkers associated with the extent of the myocardial damage may also improve the risk stratification of asymptomatic patients with severe AS and help guiding management. Finally, it should be emphasized that a personalized medicine, including this comprehensive integrative approach in heart valve clinics, should be advocated for the management of these challenging patients.

Stenotic Bicuspid and Tricuspid Aortic Valves - Micro-Computed Tomography and Biological Indices of Calcification

BACKGROUND

Valve calcification is well estimated by ex-vivo micro-computed tomography (micro-CT). The objective of this study was to investigate the associations between micro-CT findings and biological indices of calcification in aortic stenosis (AS), as well as differences between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV).Methods and Results:Aortic valves and plasma were obtained from patients undergoing valve surgery. Valves were dissected and underwent micro-CT, genetic analyses, and calcium content assessment. Plasma levels of calcification markers were measured. Forty-two patients with isolated severe AS, including 22 with BAV, were studied. BAV patients had a lower median CT value (140.0 [130.0-152.0] vs. 157.0 [147.0-176.0], P=0.002) and high-density calcification (HDC) fraction (9.3 [5.7-23.3] % vs. 21.3 [14.3-31.2] %, P=0.01), as compared with TAV. Calcification fraction (CF) correlated with AS severity (measured as maximal transvalvular pressure gradient [r=0.34, P=0.03], maximal flow velocity [r=0.38, P=0.02], and indexed aortic valve area [r=-0.37, P=0.02]). For TAV patients only, mRNA expression of integrin-binding sialoprotein correlated with CF (r=0.45, P=0.048), and the receptor activator of the nuclear factor κ-B ligand transcript correlated with HDC corrugation (r=0.54, P=0.01).

CONCLUSIONS

TAV patients with AS present more mineralized calcifications in micro-CT than BAV subjects. The relative volume of calcifications increases with the AS severity. In TAV patients, upregulated expression of genes involved in osteoblastogenesis in AS correlates with leaflet mineralization in micro-CT.

The Role of Imaging in Aortic Valve Disease

PURPOSE OF REVIEW

Aortic valve disease is the most common form of heart valve disease in developed countries. Imaging remains central to the diagnosis and risk stratification of patients with both aortic stenosis and regurgitation and has traditionally been performed with echocardiography. Indeed, echocardiography remains the cornerstone of aortic valve imaging as it is cheap, widely available and provides critical information concerning valve hemodynamics and ventricular function.

RECENT FINDINGS

Whilst diagnostic in the vast majority of patients, echocardiography has certain limitations including operator variability, potential for measurement errors and internal inconsistencies in severity grading. In particular, low-gradient severe aortic stenosis is common and challenging to diagnose. Aortic valve imaging may therefore be improved with alternative and complimentary multimodality approaches.

SUMMARY

This review investigates established and novel techniques for imaging both the aortic valve and the myocardial remodelling response including echocardiography, computed tomography, cardiovascular magnetic resonance and positron emission tomography. Moreover, we examine how the complementary information provided by each modality may be used in both future clinical practice and the research arena.

Quantification of Aortic Valve Calcifications Detected During Lung Cancer-Screening CT Helps Stratify Subjects Necessitating Echocardiography for Aortic Stenosis Diagnosis

No study has been published on aortic valve calcification (AVC) extent at lung cancer screening low-dose CT (LDCT) and its relationship with aortic stenosis (AS). The purpose of this study was to estimate the cutoff value of AVC on LDCT for detecting AS in asymptomatic Asian subjects. Six thousand three hundred thirty-eight subjects (mean age, 55.9 years ± 8.6) self-referred to health-promotion center underwent LDCT, coronary calcium scoring CT (CSCT), and echocardiography. AVC was quantified using Agatston methods on CT. AVC extent on LDCT was compared with that on CSCT, and AVC threshold for diagnosing AS was calculated. Clinical factors associated with AS and AVC were sought.AVC was observed in 403 subjects (64.9 years ± 8.7) on LDCT (6.4%), and AVC score measured from LDCT showed strong positive correlation with that from CSCT (r = 0.83, P < 0.0001). Of 403 subjects, 40 (10%) were identified to have AS on echocardiography. Cutoff value of AVC score for detecting AS was 138.37 with sensitivity of 90.0% and specificity 83.2%. On multivariate analysis, age (odds ratio [OR] = 1.10, 95% CI: 1.09-1.12) and hypertension (OR = 1.39, 95% CI: 1.10-1.76) were associated with the presence of AVC, whereas AVC extent at LDCT (OR = 104.32, 95% CI: 16.16-673.70) was the only significant clinical factor associated with AS; AVC extent on LDCT (OR = 104.32, 95% CI: 16.16-673.70) was the significant clinical factor associated with AS.The AVC extent on LDCT is significantly related to the presence of AS, and we recommend echocardiography for screening AS based on quantified AVC values on LDCT.