Characterization of the early lesion of 'degenerative' valvular aortic stenosis. Histological and immunohistochemical studies

C-reactive protein in predicting coronary artery disease in subjects with aortic valve sclerosis before diagnostic coronary angiography

BACKGROUND

Although previous studies have suggested that aortic valve sclerosis (AVS) shares common histologic features with atherosclerosis and is an indicator of significant coronary artery disease (CAD), many patients with aortic valve disease do not have coexisting coronary atherosclerotic disease and vice versa. It is important to find the subjects with AVS who are most likely to have concomitant CAD and require aggressive evaluation.

HYPOTHESIS

We hypothesized that the systemic inflammatory marker, high-sensitive C-reactive protein (hs-CRP), may be associated with AVS, and may be helpful before coronary angiography in identifying the presence of concomitant CAD in patients with AVS.

METHODS

This study included 227 patients with suspected CAD undergoing transthoracic echocardiography and coronary angiography. AVS was defined as a focal area of increased echogenicity and thickening of the aortic valve leaflets without restriction in motion. Data of atherosclerotic risk factors including hs-CRP were collected.

RESULTS

Technically satisfactory ultrasound recordings were obtained in 217 subjects (96% of enrolled patients). Patients with AVS were older (65+/-10 vs. 60+/-10 years old; P=0.0004), had higher serum creatinine levels (115.2+/-79.7 vs. 88.6 +/-35.4 micromol/L; P=0.04), and had greater prevalence of obstructive CAD (75% vs. 53%; P=0.001) than those with normal aortic valves. CRP levels were not associated with AVS, and failed to predict concomitant CAD in patients with AVS. Additionally, none of the established risk factors were independent predictors of the presence of CAD in AVS patients.

CONCLUSION

Hs-CRP levels appear to not be associated with AVS, and are of little value in terms of predicting the presence of concurrent CAD before coronary procedure.

Degeneration of native and tissue prosthetic valve in aortic position: do statins play an effective role in prevention?

Degenerative aortic valve stenosis is a common disease in western countries. When it becomes severe, it confers significant morbidity and mortality. Aortic stenosis has been recognized as a complex inflammatory and highly regulated process with histological and immunochemical similarities with the process of atherosclerosis. Hypertension, smoking and diabetes mellitus have consistently been linked to the development of aortic stenosis. Endothelial injury or other processes that contribute to coronary disease may play a role in calcific aortic stenosis. Several observational studies suggests that the key factors of aortic stenosis are lipoproteins and that medical therapies with cholesterol lowering drugs may retard its progression. Similarly, it has been suggested that the process of degeneration of the tissue heart valve has been associated with the same risk factors of atherosclerosis and shares many histological and molecular characteristics. Assuming all this concept, and evaluating the results of a retrospective study it has been suggested to use statin also as medical therapy able to prevent tissue valve degeneration. Randomized controlled clinical trials will be needed to demonstrate the role of lipid intervention to prevent the progression of aortic stenosis and the degeneration of tissue heart valves.

Is there a role of statins in the prevention of aortic biological prostheses degeneration

It has been recently observed that statins might slow the progression of aortic stenosis or sclerosis. Preliminary reports suggested a similar positive effect in reducing the degeneration of aortic valve bioprostheses even though this hypothesis should be further proven and supported by new data. In this review the present evidences of the possible effects of statins in this field are discussed.

Emerging medical treatments for aortic stenosis: statins, angiotensin converting enzyme inhibitors, or both?

Aortic stenosis is the most common adult heart valve condition seen in the Western world and its incidence continues to rise. No established disease modifying treatments retard progression of the stenotic process. Recent insights into the pathogenesis of calcific aortic stenosis suggest that the disease mimics atherosclerosis. The natural history and progression of calcific aortic stenosis are described with particular emphasis on new and emerging medical treatments that may modify the disease process. In particular, statins and angiotensin converting enzyme inhibitors appear to hold promise but definitive evidence from large clinical trials is awaited.

Possible role for mast cell-derived cathepsin G in the adverse remodelling of stenotic aortic valves

AIMS

Aortic stenosis (AS) is characterized by extensive remodelling of the valves, including infiltration of inflammatory cells, extracellular matrix degradation, and fibrosis. The molecular mechanisms behind this adverse remodelling have remained obscure. In this article, we study whether cathepsin G, an angiotensin II (Ang II)-forming elastolytic enzyme, contributes to progression of AS.

METHODS AND RESULTS

Stenotic aortic valves (n = 86) and control valves (n = 17) were analysed for cathepsin G, transforming growth factor-beta1 (TGF-beta1), and collagens I and III with RT-PCR and immunohistochemistry. Valvular collagen/elastin ratio was quantified by histochemistry. In stenotic valves, cathepsin G was present in mast cells and showed increased expression (P < 0.001), which correlated positively (P < 0.001) with the expression levels of TGF-beta1 and collagens I and III. TGF-beta1 was also present in mast cell-rich areas and cathepsin G induced losartan-sensitive TGF-beta1 expression in cultured fibroblasts. Collagen/elastin ratio was increased in stenotic valves (P < 0.001) and correlated positively with smoking (P = 0.02). Nicotine in cigarette smoke activated mast cells and induced TGF-beta1 expression in cultured fibroblasts. Fragmented elastin was observed in stenotic valves containing activated cathepsin G-secreting mast cells and in normal valves treated with cathepsin G.

CONCLUSION

In stenotic aortic valves, mast cell-derived cathepsin G may cause adverse valve remodelling and AS progression.

Development of mild aortic valve stenosis in a rabbit model of hypertension

OBJECTIVES

This study was designed to investigate the association between hypertension and aortic valve stenosis (AVS) in a rabbit model.

BACKGROUND

Degenerative AVS is a prevalent disease in elderly persons. Its molecular mechanisms remain unclear, in part because of the absence of experimental models. Epidemiologic data suggest a link between hypertension and AVS. However, there has been no evidence of a cause-effect relationship.

METHODS

New Zealand White rabbits were divided into two groups: 1) animals (n = 20) instrumented according to one-kidney/one-clip hypertensive model; and 2) control animals (n = 10) sham operated. Echocardiography (S12 MHz) was used to assess aortic valve (AV) morphology and function as well as left ventricular mass at baseline and after two and four months of hypertension.

RESULTS

Blood pressure and left ventricular mass increase were highly significant in the animal model but not in controls at two months, without noticeable AV function abnormalities. After 4 months, however, 14 hypertensive survived animals showed a 14.6% reduction of AV area (0.240 +/- 0.063 cm2 vs. 0.205 +/- 0.060 cm2, p < 0.05), a 19.6% increase of AV thickness (0.056 +/- 0.011 cm vs. 0.067 +/- 0.010 cm, p < 0.001), a 40.4% increase of transvalvular mean gradient (5.35 +/- 2.26 mm Hg vs. 7.51 +/- 3.73 mm Hg, p < 0.05) and a 63.6% increase of transvalvular maximal gradient (10.56 +/- 3.68 mm Hg vs. 17.28 +/- 10.95 mm Hg, p < 0.05). Control animals did not show significant changes.

CONCLUSIONS

We report a novel experimental model of AVS in rabbits that may prove useful in studying the progression of the disease and the efficacy of new treatments. The present findings support the hypothesis of a causal link between hypertension and AVS.

Relations of inflammation and novel risk factors to valvular calcification

Investigators have suggested that inflammation may play a role in the pathogenesis of valve calcium. Participants in the Framingham Heart Study's offspring cohort had systemic levels of C-reactive protein, intercellular adhesion molecule-1, interleukin-6, and monocyte chemoattractant protein-1 measured at examination cycle 7. Mitral annular calcium, aortic annular calcium, aortic sclerosis, and aortic stenosis were assessed by echocardiography at examination cycle 6. Logistic regression was used to examine the odds of valvular calcium per 1 unit increase in inflammation (ISUM), a summary statistic of all normalized deviates of the individual markers. Two thousand six hundred eighty-three participants (mean age 61 +/- 10 years; 52% women) were analyzed: 8.2% (n = 216) had > or = 1 calcified valve or annulus; 89 had mitral annular calcium, 78 had aortic annular calcium, 135 had aortic sclerosis, and 33 had aortic stenosis. Participants with valvular calcium were older and were more likely to have hypertension and diabetes mellitus. Participants with valve calcium had higher median levels of all markers. For each log unit increase in ISUM, after adjustment for age and gender, there was an associated 1.1-fold increased odds of > or = 1 calcified valve (p = 0.02); the odds ratios were no longer significant after adjustment for cardiovascular disease risk factors (odds ratio 1.0, 95% confidence interval 0.9 to 1.1). Similar results were obtained for the individual markers and the odds of > or = 1 calcified valve. In conclusion, inflammatory markers were elevated in patients with valvular calcium. Our findings suggest that much of the observed association between systemic inflammatory markers and valvular calcium may be due to shared risk factors.

A high fat/high carbohydrate diet induces aortic valve disease in C57BL/6J mice

OBJECTIVES

The purpose of this study was to compare aortic valve function and morphology in adult wild-type (WT) mice and in low-density lipoprotein receptor-deficient (LDLr-/-) mice fed or not fed a high-fat/high-carbohydrate (HF/HC) diet.

BACKGROUND

Observations suggest a link between degenerative aortic valve stenosis (AS) and atherosclerosis. Aortic valve stenosis has been successfully induced in animal models of extreme hypercholesterolemia, but these models are less relevant to humans. It is not known if a proatherogenic HF/HC diet without added cholesterol could have the same negative impacts.

METHODS

Forty C57BL/6J mice were divided into four groups: WT + normal diet, WT + HF/HC diet, LDLr-/- with a normal diet, and LDLr-/- with a HF/HC diet. Aortic valve function and histology were evaluated by echocardiography after four months.

RESULTS

Wild-type mice on a HF/HC diet became mildly hypercholesterolemic, obese, and hyperglycemic. As expected, LDLr-/- mice became severely hypercholesterolemic. Both WT and LDLr-/- mice on a HF/HC diet displayed smaller valve areas and higher transvalvular velocities (p < 0.01) after four months. Aortic valve leaflets were thicker and infiltrated with lipids and macrophages in both HF/HC groups.

CONCLUSIONS

A HF/HC diet in mice results in significant aortic valve abnormalities. Putting WT mice on a HF/HC diet reproduced a combination of atherogenic factors (obesity, mild dyslipidemia, and hyperglycemia) more commonly encountered in humans than isolated severe hypercholesterolemia. Severe hypercholesterolemia was not a prerequisite in our model. This experimental model suggests that AS development is multifactorial and that hypercholesterolemia should not be the only target in this disease.

Effect of the anti-anginal agent, perhexiline, on neutrophil, valvular and vascular superoxide formation

The prophylactic anti-anginal agent, perhexiline, may also be effective in acute coronary syndromes and advanced aortic valvular stenosis, conditions associated with enhanced inflammation. Its potential effects on superoxide formation via NADPH oxidase were measured by lucigenin-mediated chemiluminescence. Perhexiline inhibited superoxide formation in intact neutrophils stimulated with formyl Met Leu Phe (fMLP) 4 muM or with phorbol myristate acetate (PMA) 162 nM - IC50 2.3 microM (1.5-3.6), n=4. Sub-unit assembly of NADPH oxidase by PMA was unaffected by pretreatment with perhexiline 2 microM, a concentration which reduced superoxide formation by 44+/-5% (n=4) in intact neutrophils. Perhexiline inhibited preassembled neutrophil NADPH oxidase and that in membranes of pig valve interstitial cells, human umbilical vein endothelial cells (HUVECs) and cardiac fibroblasts, but not that in rat aorta (rings or membrane preparations). These data imply that perhexiline inhibits the phagocytic NADPH oxidase directly, and that pig aortic valvular interstitial cells possess a similar enzyme, a conclusion supported by immunohistochemical localisation of the gp91phox subunit in these cells. However further study is required to clarify the effect of perhexiline on different NADPH oxidase isoforms particularly in the vasculature.

Statin therapy of calcific aortic stenosis: hype or hope?

Calcific aortic stenosis, with a prevalence of 3-9%, is the most frequent heart valve disease and the main cause for valve replacement in patients over 60 years of age. Once thought to be caused by a passive calcium precipitate within the aortic valve leaflets, there is now increasing evidence that development and progression of calcific aortic valve disease may be triggered by underlying genetic and cardiovascular risk factors, and is regulated by an active cellular process involving inflammatory pathways. Targeted drug therapy to prevent the progression of calcific aortic valve disease should ideally be based on the knowledge of risk factors and the molecular pathogenesis of the disease. Conflicting data exists on the potency of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (i.e. statins) to influence both risk factors and inflammatory pathways by lowering lipid levels and exerting anti-inflammatory properties, respectively. In this review, various aspects of the molecular pathogenesis of calcific aortic stenosis will be summarized and connected with recent experimental and clinical studies that address the potential benefit of the targeted drug therapy by statins in order to prevent the progression of the disease.

Increased prevalence of coronary artery disease, silent myocardial ischemia, complex ventricular arrhythmias, atrial fibrillation, left ventricular hypertrophy, mitral annular calcium, and aortic valve calcium in patients with chronic renal insufficiency

Cardiovascular morbidity and mortality is high in patients with chronic renal insufficiency. Patients with chronic renal insufficiency have an increased prevalence of coronary artery disease, silent myocardial ischemia, complex ventricular arrhythmias, atrial fibrillation, left ventricular hypertrophy, mitral annular calcium, and aortic valve calcium than patients with normal renal function. These risk factors for cardiovascular morbidity and mortality contribute to the increased incidence of cardiovascular morbidity and mortality seen in patients with chronic renal insufficiency.

Radiation following percutaneous balloon aortic valvuloplasty to prevent restenosis (RADAR pilot trial)

OBJECTIVES

We wished to determine the feasibility and early safety of external beam radiation therapy (EBRT) used following balloon aortic valvuloplasty (BAV) to prevent restenosis.

BACKGROUND

BAV for calcific aortic stenosis (AS) has been largely abandoned because of high restenosis rates, i.e., > 80% at 1 year. Radiation therapy is useful in preventing restenosis following vascular interventions and treating other benign noncardiovascular disorders.

METHODS

We conducted a 20-patient, pilot study evaluating EBRT to prevent restenosis following BAV in elderly patients with calcific AS. Total doses ranging from 12-18 Gy were delivered in fractions over a 3-5 day post-op period to the aortic valve. Echocardiography was performed pre and 2 days post-op, 1, 6, and 12 months following BAV.

RESULTS

One-year follow-up is completed (age 89 +/- 4). There were no complications related to EBRT. Eight patients died prior to 1 year; 5 of 10 (50%) in the low-dose (12 Gy) group and 3 of 10 (30%) in the high-dose (15-18 Gy) group. None of these 8 patients had restenosis, i.e., > 50% loss of the initial AVA gain, and only three deaths were cardiac in origin. One patient underwent aortic valve replacement and none repeated BAV. By 1 year, 3 of the initial 10 (30%) in the low-dose group and 1 of 9 (11%) in the high-dose group demonstrated restenosis (21% overall).

CONCLUSIONS

EBRT following BAV in elderly patients with AS is feasible, free of early complications, and holds promise in reducing the 1 year restenosis rate in a dose-dependent fashion.

The association of hypertension and aortic valve sclerosis

BACKGROUND

Aortic valve sclerosis (AVS), a condition of thickening and calcification of the normal trileaflet aortic valve without the obstruction to left ventricular outflow, is likely the initial stage in the development of aortic stenosis and is associated with an increased incidence of cardiovascular events. The objective of this study is to critically review the data on the association of blood pressure and hypertension with AVS.

METHODS

A systematic search of MEDLINE and EMBASE (to June 2004) was conducted using the keywords hypertension and aortic valve. All English language papers were examined if they dealt with hypertension and AVS. All studies were included for analysis if they had a control group.

RESULTS

Three population-based, cross-sectional studies with a total sample size of 6450 individuals showed a consistent and significant relationship between hypertension and AVS with an odds ratio (OR) ranging from 1.23 to 1.74. Smaller case-control studies with a total sample size of 1609 individuals did not show consistent results but the OR ranged from 1.75 to 2.38. Only one small study (n = 188) showed fewer cases with hypertension and AVS than in the control group. Hypertension was a significant factor remaining in multivariate analysis after consideration of age and other risk factors in several cross-sectional studies. In contrast, other studies with blood pressure measurements consistently showed no increased blood pressures in the presence of AVS. However, these studies did not examine the prevalence of AVS within age-adjusted blood pressure levels.

CONCLUSIONS

Cross-sectional population-based studies present evidence of an association between hypertension and AVS with an OR between 1.23 and 1.74. The major limitation in establishing a causal relationship is the failure to demonstrate a gradient of risk between increasing blood pressure and increasing incidence of AVS. In addition, the literature is confounded by the wide variety of definitions for AVS as well as hypertension. At this time, further data is required to conclude that there is a causal relationship between AVS and elevated blood pressure.

Tooth loss is independently associated with the risk of acquired aortic valve sclerosis

BACKGROUND

Several studies have shown that periodontal disease and atherosclerosis are associated. Aortic valve sclerosis (AVS) represents the sum of processes that are similar to the development of atherosclerosis. The present analysis was performed to investigate associations between periodontal disease, tooth loss, and AVS.

METHODS

The population-based SHIP was conducted in northeast Germany. A study population of 2341 individuals aged > or =45 years was available for the present analysis. Aortic valve sclerosis was determined by echocardiography. Periodontal status was assessed by attachment loss and tooth loss.

RESULTS

The prevalence of AVS was 29.9%. Logistic regression analyses did not reveal attachment loss as an independent risk factor for AVS. However, a reduced number of teeth was independently associated with AVS. Other risk factors for AVS were age, history of myocardial infarction, body mass index, pulse pressure, plasma fibrinogen and lipoprotein (a) levels, and the use of drugs that act on the renin-angiotensin system.

CONCLUSION

A reduced number of teeth was independently associated with the risk of AVS. This finding further strengthens the link between oral health and cardiovascular disorders.

Are angiotensin converting enzyme inhibitors beneficial in patients with aortic stenosis?

Angiotensin converting enzyme (ACE) inhibitors may become an accepted form of treatment for aortic stenosis in the future.

Tissue resident C reactive protein in degenerative aortic valves: correlation with serum C reactive protein concentrations and modification by statins

OBJECTIVE

To assess aortic valve probes for valvar C reactive protein (CRP) presence, the relation between valvar and serum CRP, and a possible modification of CRP by statin medication.

SETTING

Tertiary referral centre.

PATIENTS AND DESIGN

End stage, degenerative valve tissue was taken from 81 patients, 57 with non-rheumatic aortic valve stenosis (AS) and 24 with degenerative aortic valve bioprosthesis (BP). Five non-stenosed valves served as controls. Tissue from four non-implanted bioprostheses was also examined. The presence and location of CRP was analysed by use of immunostaining and morphometry. Serum CRP concentrations were measured preoperatively.

RESULTS

The majority of AS and BP valves exhibited CRP labelled cells, predominantly localised to the valvar fibrosa. The expression of CRP was much higher in BP than in AS (by a factor of 3.7, p = 0.03). Notably, non-stenosed aortic valves and non-implanted bioprostheses did not have CRP signalling. Serum CRP was also increased with BP (by a factor of 2.5, p = 0.02) and was significantly correlated with valvar CRP expression (r = 0.54, p < 0.001). The main finding in patients with (n = 26) and without statin treatment (n = 55) was that both valvar CRP expression (p = 0.02) and serum CRP concentrations (p = 0.04) were lower in the statin treated group.

CONCLUSIONS

CRP was found in a large series of degenerative aortic valves, more often in bioprostheses than in native cusps. Serum CRP concentrations may reflect inflammatory processes within the aortic valve. The association of statin treatment with decreases in both valvar and serum CRP concentrations may explain known pleiotropic effects of statins in patients with aortic stenosis.

Age-related changes in aortic valve with emphasis on the relation between pressure loading and thickened leaflets of the aortic valves

BACKGROUND

The information of the prevalence of TAV and its relation to aortic stenosis in a large-scale human population is limited.

METHODS

An echocardiographic study was performed prospectively in 2850 subjects to determine the relationship between age and the thickened aortic valves (TAV). Another simulated study was designed to test the hypothesis that the noncoronary leaflet may have a greater diastolic loading than the right or left coronary leaflet.

RESULTS

The prevalence of TAV in this population was 14.4% (410/2850). It was 0% in the <39 years old; however, the prevalence of TAV increased progressively with age: it was 10.0% in the middle age group, 17.0% in the elderly group, and 53.7% in the octogenarian group (Chi-square test for linear trend, chi2=67.10, p<0.001). A greater frequency of TAV was noted at noncoronary leaflet (57.0%) than at either right (22.3%) or left (20.6%) coronary leaflet (chi2=5.99, df=2, p<0.001). The prevalence of aortic stenosis (AS) tended to increase with age (Chi-square test for linear trend, chi2=37.85, p<0.001). The simulated study demonstrated that the sinus of Valsalva without a coronary leaflet had a higher pressure loading than that with a coronary leaflet.

CONCLUSION

This study demonstrates that the prevalences of TAV and AS increase progressively with age. A greater frequency of TAV is found at the noncoronary leaflet than at either the right or left coronary leaflet. The simulated study supports our hypothesis that the noncoronary leaflet may bear a greater pressure loading than either the left or right coronary leaflet.

CT of valvular heart disease

Although the incidence of valvular heart disease is significantly less than before the introduction of antibiotic therapy, chronic mitral and aortic valve disease continues to be found in the adult population. CT examination reveals characteristic chamber volume and myocardial mass changes expected in patients with valvular obstruction and regurgitation. Furthermore, CT provides sensitive visualization of annular and valve leaflet calcification, both of which are important findings for determining the presence of disease and estimating the significance of valvular dysfunction identified on examination. Although CT is by no means the first diagnostic modality to be employed in management of patients with valvular heart disease, it does reveal the sequelae of such disease, and may, in fact, provide insight into the significance of clinical or echocardiographic findings. Improved temporal resolution will increase the accuracy of CT diagnosis, and further expand its use for diagnosing and managing patients with cardiac disease in general, and valvular heart disease, in particular.

Cells of primarily extra-valvular origin in degenerative aortic valves and bioprostheses

AIMS

We assessed aortic valves from patients with non-rheumatic aortic valve stenosis (AS) and with degenerative aortic valve bioprostheses (BP) for the presence of progenitor cell and leukocyte subtype-specific markers.

METHODS AND RESULTS

Diseased valve probes from a total of 87 patients (60 AS and 27 BP) were studied. We assessed presence and localization of endothelial progenitor cells (EPCs: CD34, CD133), dendritic cells (DCs: S100), T-lymphocytes (CD3), and macrophages (CD68) by immunohistochemical and morphometric analyses. In the majority of valves, we detected cell-bound signals of CD34 (48% of AS, 74% of BP, respectively), CD133 (58%/81%), S100 (58%/93%), CD3 (62%/81%), and CD68 (78%/93%). Labelled cells were predominantly localized within the valvular fibrosa. As key results, frequency of EPCs, DCs, macrophages, and lymphocytes was found significantly higher in BP when compared with AS (CD34: 19.2+/-23.2 vs. 5.7+/-13.0%; CD133: 13.7+/-12.4 vs. 5.5+/-8.3%; S100: 15.2+/-12.2 vs. 5.7+/-8.9%; CD3: 3.3+/-2.7 vs. 1.1+/-1.4%; CD68: 35.3+/-26.6 vs. 3.4+/-4.1%; each P<or=0.001).

CONCLUSION

EPCs and DCs were detected in a large collective of degenerative aortic valves, more frequently in bioprostheses than in native cusps. Aortoluminal presence of these primarily extra-valvular cells co-localized with inflammatory cells is a novel key feature involved in aortic valve degeneration.

Age-associated aortic stenosis in apolipoprotein E-deficient mice

OBJECTIVES

The present study was designed to assess aortic valve morphology and function in mice of advanced age. We also evaluated the potential contribution of bone-marrow-derived cells to the pathogenesis of aortic stenosis.

BACKGROUND

Age-associated valvular degeneration is characterized by lipid accumulation, collagen deposition, and calcification containing smooth muscle-like cells and osteoblast-like cells. Cellular and molecular factors that mediate these changes remain unknown.

METHODS

We extensively examined the aortic valves of senile wild-type and apolipoprotein E (ApoE)-/- mice with echocardiography. The aortic valves were analyzed by immunohistochemistry and electron microscopy. The bone marrow of wild-type and ApoE-/- mice was reconstituted with that of green fluorescent protein (GFP) or beta-galactosidase (LacZ) mice, which expressed GFP or LacZ ubiquitously.

RESULTS

Transaortic flow velocity was correlated with age in wild-type and ApoE-/- mice. The aortic valves of old ApoE-/- mice showed sclerosis that resembled the pathology of human aortic stenosis. A significant number of GFP-positive cells (10.7 +/- 4.1%) in the sclerotic valves of ApoE-/- mice expressed alpha-smooth muscle actin, whereas most of the GFP-positive cells were identified as endothelial cells or macrophages in wild-type mice. There were bone-marrow-derived cells that were positive for osteoblast-related proteins near the sites of ectopic calcification. The sclerotic valves displayed frequent apoptotic cell death and chemokine expression.

CONCLUSIONS

Senile ApoE-deficient mice display aortic valve sclerosis that is similar to that observed in humans. The sclerotic valves displayed frequent apoptotic cell death and chemokine expression. Smooth muscle-like cells observed in degenerative valves might derive, at least in part, from bone marrow.

Is it time to prescribe statins to patients with calcified aortic stenosis?

Aortic stenosis (AS) is a common disease especially in the older population. It is associated with high mortality and morbidity. Recent data suggest that coronary artery disease and AS share common risk factors. Retrospective studies suggest that statins might slow the progression of AS but there are no randomized clinical trial data available. It would seem that statins can be considered for medical treatment of AS; however, this needs to be investigated in future randomized clinical trials.

Atherosclerosis of the aorta is common in patients with severe aortic stenosis: An intraoperative transesophageal echocardiographic study

OBJECTIVE

Several studies have recently reported an association between aortic valve calcification and atherosclerosis of the cardiovascular system, suggesting that aortic valve calcification might represent an atherosclerosis-like process. Hence the aim of the present study was to determine whether there is a similar association between aortic stenosis and aortic atheromas.

METHODS

We evaluated the records and echocardiographic videotapes of 91 consecutive patients with severe aortic stenosis who underwent intraoperative transesophageal echocardiography before aortic valve replacement to measure the presence and characteristics of aortic atheromas. There were 50 men (55%) and 41 women (45%). The mean age was 71.9 +/- 9.4 years (range, 34-91 years). These patients were compared with 91 sex-and age-matched patients without aortic stenosis who underwent transesophageal echocardiography for various indications. Aortic atheroma was defined as localized intimal thickening of 3 mm or larger. A lesion was considered complex if there was a plaque extending 5 mm or more into the aortic lumen; if the lesion was protruding, mobile, or ulcerated; or both.

RESULTS

The aortic stenosis group had significantly higher rates of aortic atheromas (85% vs 37%, P < .001) and complex atheromas (47% vs 9%, P < .001) compared with the control group. In the vast majority of patients in the aortic stenosis group, the aortic atheromas were localized in the aortic arch (60 [66%] patients, with 50% being complex aortic atheromas) and in the descending aorta (70 [77%] patients, with 45.7% being complex aortic atheromas); in only 4 (4.4%) patients, the aortic atheromas were localized in the ascending aorta (50% complex aortic atheromas).

CONCLUSIONS

There is a strong association between the presence of severe aortic stenosis and the presence and severity of aortic atheromas, suggesting that aortic stenosis might be a manifestation of the atherosclerotic process. These findings imply that (1) aggressive atherosclerotic risk-factor modification for patients with aortic stenosis might be advisable and (2) consideration of evaluation of the aorta by means of transesophageal echocardiography before aortic valve replacement in selected patients might be helpful.

A randomized trial of intensive lipid-lowering therapy in calcific aortic stenosis

BACKGROUND

Calcific aortic stenosis has many characteristics in common with atherosclerosis, including hypercholesterolemia. We hypothesized that intensive lipid-lowering therapy would halt the progression of calcific aortic stenosis or induce its regression.

METHODS

In this double-blind, placebo-controlled trial, patients with calcific aortic stenosis were randomly assigned to receive either 80 mg of atorvastatin daily or a matched placebo. Aortic-valve stenosis and calcification were assessed with the use of Doppler echocardiography and helical computed tomography, respectively. The primary end points were change in aortic-jet velocity and aortic-valve calcium score.

RESULTS

Seventy-seven patients were assigned to atorvastatin and 78 to placebo, with a median follow-up of 25 months (range, 7 to 36). Serum low-density lipoprotein cholesterol concentrations remained at 130+/-30 mg per deciliter in the placebo group and fell to 63+/-23 mg per deciliter in the atorvastatin group (P<0.001). Increases in aortic-jet velocity were 0.199+/-0.210 m per second per year in the atorvastatin group and 0.203+/-0.208 m per second per year in the placebo group (P=0.95; adjusted mean difference, 0.002; 95 percent confidence interval, -0.066 to 0.070 m per second per year). Progression in valvular calcification was 22.3+/-21.0 percent per year in the atorvastatin group, and 21.7+/-19.8 percent per year in the placebo group (P=0.93; ratio of post-treatment aortic-valve calcium score, 0.998; 95 percent confidence interval, 0.947 to 1.050).

CONCLUSIONS

Intensive lipid-lowering therapy does not halt the progression of calcific aortic stenosis or induce its regression. This study cannot exclude a small reduction in the rate of disease progression or a significant reduction in major clinical end points. Long-term, large-scale, randomized, controlled trials are needed to establish the role of statin therapy in patients with calcific aortic stenosis.

Density of Chlamydia pneumoniae is increased in fibrotic and calcified areas of degenerative aortic stenosis

BACKGROUND

The process of aortic degeneration associated with calcified aortic stenosis shares many similarities with coronary artery atherosclerosis. Inflammation and infection are involved in both diseases. Chlamydia pneumoniae has been identified in atherosclerotic plaques. However, the studies about the presence of C. pneumoniae in degenerative aortic stenotic valves are not conclusive.

OBJECTIVE

We investigated whether an association exists between the density of C. pneumoniae and fibrosis or calcification in aortic stenosis.

DESIGN

Autopsy and surgical specimens were divided into 3 groups: Normal, 11 normal autopsy valves Atherosclerosis, 10 autopsy valves from patients with systemic atherosclerosis and no aortic stenosis and Aortic stenosis, 14 surgical specimens of aortic valves replaced due to aortic stenosis.

SETTING

Heart Institute (InCor), University of São Paulo Medical School.

PATIENTS

Aortic valves from patients aged 52+/-16 years, 69+/-9 years, and 71+/-8 years.

INTERVENTION

Specimens were evaluated by immunohistochemical technique (to detect C. pneumoniae antigens), in situ hybridization, and electron microscopy (to quantify the density of C. pneumoniae in the valves).

MEASUREMENTS

The aortic stenosis group was analyzed according to 3 subregions: aortic stenosis-preserved, peripheral preserved regions; aortic stenosis-fibrosis, peri-calcified fibrotic tissue; and aortic stenosis-calcification, calcified nodules.

RESULTS

The median values of C. pneumoniae antigens were 0.09, 0.30, 0.18, 1.33, and 3.3 in groups Normal, Atherosclerosis, Aortic stenosis-preserved, Aortic stenosis-fibrosis, and Aortic stenosis-calcification, respectively. The amount of C. pneumoniae was greater in the Atherosclerosis and Aortic stenosis-calcification groups than in the Normal group (P<0.05). C. pneumoniae was greater in the Aortic stenosis group in the calcified and fibrotic regions than in preserved region (P<0.05).

CONCLUSION

An association was found between the higher density of C. pneumoniae and fibrosis/calcification in stenotic aortic valves.

Atherosclerosis-like lesions of the aortic valve are common in adults of all ages: a necropsy study

OBJECTIVE

To determine the presence and size of atherosclerosis-like lesions in aortic valves of unselected adults of all ages.

DESIGN

Necropsy study.

SETTING

Departments of Forensic Medicine and Pathology at the University of Oulu and the Oulu University Hospital in Finland.

SUBJECTS

48 consecutive unselected adult subjects (15 subjects aged 20-40 years, 17 aged 41-60, and 16 aged >or= 61) undergoing necropsy.

MAIN OUTCOME MEASURES

Detection of the presence of atherosclerosis-like lesions and mineralisation in aortic valves, and morphometrical measurement of the size of lesions.

RESULTS

None of the necropsy subjects had aortic stenosis and only two subjects had macroscopic calcification of the aortic valve. Of 48 subjects, however, 45 had an atherosclerosis-like subendothelial thickening above the elastic lamina on the aortic side of at least one of the valve leaflets. Of 15 young subjects aged 20-40 years, eight had a lesion in the right coronary cusp of the aortic valve and 12 had a lesion in at least one of the three aortic valve leaflets. Of 17 middle aged subjects, 16 had an early lesion in the right coronary cusp and all had a lesion in at least one of the valve leaflets. In the oldest age group, all 16 subjects had a lesion in every valve leaflet. The mean lesion area in the three valve leaflets varied from 0.1-0.2 mm(2) in young subjects, 0.5-0.8 mm(2) in middle aged, and 1.3-2.3 mm(2) in elderly subjects (p < 0.001). Microscopic calcification in the right coronary cusp of the aortic valve was observed in 12 of 17 middle aged and 14 of 16 elderly subjects but only in one young subject.

CONCLUSIONS

Atherosclerosis-like lesions in the aortic valve are prevalent in adults of all age groups, including young subjects aged 20-40 years, suggesting that the disease process leading to aortic stenosis is common, often beginning in early adulthood.

Prognostic value of carotid intima-media thickness in detection of coronary atherosclerosis in patients with calcified aortic valve stenosis

OBJECTIVE

Aortic stenosis (AS) coexists with coronary artery disease (CAD) in at least 30% of patients. Patients with concomitant CAD may benefit from simultaneous coronary bypass grafting. This study aimed to evaluate the prognostic value of carotid intima-media thickness (IMT) in patients with AS in assessing concomitant CAD.

METHODS

Group I consisted of 33 patients (mean age +/- SD, 61.0 +/- 8.2 years; 18 men and 15 women) with AS but without CAD on angiograms. Group II consisted of 34 patients (64.4 +/- 8.0 years; 25 men and 9 women) with AS and CAD confirmed angiographically. A control group included 36 patients (61.2 +/- 4.9 years; 18 men and 18 women) with normal coronary arteries and no AS. Maximal IMT was assessed in all patients at the common carotid artery, bulb, and internal carotid artery and expressed as a mean value.

RESULTS

There were no differences among the respective groups with regard to age, sex, frequency of hypertension, diabetes, and smoking habit, although patients with CAD were more often hyperlipemic (P = .038). The IMT of the common carotid artery, bulb, and internal carotid artery was significantly higher in patients with AS and CAD compared with both the control group and patients with AS only. The multivariable regression model revealed that CAD (P < .001), AS (P = .006), male sex (P = .034), age (P < .001), and diabetes mellitus (P = .047) were independent risk factors for IMT thickening. A mean IMT value of greater than 1.2 mm was predictive (sensitivity, 73.5%; specificity, 72.7%) of concomitant CAD in patients with AS.

CONCLUSIONS

Intima-media thickness increases in patients with AS. The greatest IMT values are observed in patients with both AS and CAD. Patients with AS might be suspected of having CAD when the IMT value exceeds 1.2 mm.

Aortic valve sclerosis is associated with preclinical cardiovascular disease in hypertensive adults: the Hypertension Genetic Epidemiology Network study

RATIONALE

Aortic valve sclerosis (AVS) has been associated with atherosclerosis and increased all-cause and cardiovascular death. However, whether AVS is associated with preclinical cardiovascular disease among adults at high risk because of hypertension has not been determined in a population-based sample.

METHODS AND RESULTS

Clinical and echocardiographic parameters were measured in 1624 hypertensive participants (54 +/- 11 years, 65% women, 63% black, 17% diabetic, 19% smokers) without significant valvular or cardiovascular diseases in the population-based Hypertension Genetic Epidemiology Network study. The 152 participants with AVS (9.4%), compared with participants without AVS, were older, more often white, male, treated for hypertension or hypercholesteromia (all P < 0.05) and had longer duration and worse hypertension, but did not differ in diabetes status, smoking or fenfluramine use. Adjusting for age, gender and race, the AVS group had higher total cholesterol/high-density lipoprotein-cholesterol (P < 0.05). Controlling for age, gender, race and other clinical covariates, AVS was independently associated with higher septal, posterior and relative wall thicknesses, isovolumic relaxation time and left atrial diameter, and with mild aortic regurgitation and mitral annular calcification (all P < 0.05).

CONCLUSIONS

In a population-based sample of hypertensive adults, AVS was prevalent (9.4%) and associated with a proatherogenic clinical profile and abnormal left ventricular geometry and filling, increased left atrial size and mitral annular calcification, which may contribute to the adverse prognosis associated with AVS.

Aortic sclerosis: not an innocent murmur but a marker of increased cardiovascular risk

The detection of an ejection systolic murmur in the aortic valve region often corresponds to a diagnosis of aortic sclerosis or minor disruption of the aortic valve with associated turbulence but minimal obstruction. Aortic sclerosis has two important clinical implications. Firstly, aortic sclerosis is an antecedent to clinically significant aortic valve obstruction and, secondly, it acts as a marker of increased risk of cardiovascular events. This article reviews the evidence that aortic sclerosis is a useful adjunctive tool in cardiovascular risk stratification and that its progression to haemodynamically significant aortic stenosis is a potential focus for individual monitoring and for interventional studies.

Spatial heterogeneity of endothelial phenotypes correlates with side-specific vulnerability to calcification in normal porcine aortic valves

Calcific aortic valve sclerosis involves inflammatory processes and occurs preferentially on the aortic side of endothelialized valve leaflets. Although the endothelium is recognized to play critical roles in focal vascular sclerosis, the contributions of valvular endothelial phenotypes to aortic valve sclerosis and side-specific susceptibility to calcification are poorly understood. Using RNA amplification and cDNA microarrays, we identified 584 genes as differentially expressed in situ by the endothelium on the aortic side versus ventricular side of normal adult pig aortic valves. These differential transcriptional profiles, representative of the steady state in vivo, identify globally distinct endothelial phenotypes on opposite sides of the aortic valve. Several over-represented biological classifications with putative relevance to endothelial regulation of valvular homeostasis and aortic-side vulnerability to calcification were identified among the differentially expressed genes. Of note, multiple inhibitors of cardiovascular calcification were significantly less expressed by endothelium on the disease-prone aortic side of the valve, suggesting side-specific permissiveness to calcification. However, coexisting putative protective mechanisms were also expressed. Specifically, enhanced antioxidative gene expression and the lack of differential expression of proinflammatory molecules on the aortic side may protect against inflammation and lesion initiation in the normal valve. These data implicate the endothelium in regulating valvular calcification and suggest that spatial heterogeneity of valvular endothelial phenotypes may contribute to the focal susceptibility for lesion development.

Association between progression of aortic valve calcification and coronary calcification: assessment by electron beam tomography

RATIONALE AND OBJECTIVES

It has been demonstrated that aortic valve calcification (AVC) shares many similarities with coronary atherosclerosis, including risk factors and pathologic characteristics. We sought to examine the relationship of AVC to coronary artery calcification (CC), to assess whether similar risk factors affect the process in a similar way.

MATERIALS AND METHODS

The study included 620 asymptomatic persons (513 men and 107 women, mean age 59 years range [30-82]) who underwent two consecutive electron beam tomography (EBT) scans at least 1 year apart (mean 3.3 years). Calcification scores were obtained by summation of Agatston and volumetric scores. Stabilization of calcium was defined as no increase in score per year or positive percent change in score </=1%/year. Progression was defined as a positive percent change in score >1%/year. Of 106 with AVC, 105 (99%) had CC. Sixty-five patients had an AVC >10 on initial scan, and 50 (77%) demonstrated progression on the follow-up scan. Of 394 participants with CC >10 on initial scan, follow-up scans showed CC stabilization in 64 (16.2%) and CC progression in 330 (83.8%). Patients with AVC were significantly older than those with only CC (64.5 versus 56.5 years, P < .0001). The average age of the patient with AVC was 7 years older than the average age with CC. AVC (by volumetric score) progressed more rapidly in patients with diabetes (P = .036) and smoking (P = .042) than those without.

RESULTS

We found no difference in the degree of change in the CC scores (by Agatston or volumetric methods) over time between men and women, or in any baseline cardiac risk factor (P > .05 for all measures). In 65 patients with both AVC and CC >10, there was a significant association between progression of AVC and CC (P = .047); the absolute rate of change of AVC was 24.5 +/- 43.2 %/year, and CC was 28.0 +/- 49.1 %/year.

CONCLUSION

Virtually all patients with AVC had CC, potentially explaining the coronary risk associated with AVC. There is substantially parallel development between rates of progression of EBT-assessed AVC and CC.

Inflammatory regulation of extracellular matrix remodeling in calcific aortic valve stenosis

BACKGROUND

Calcific aortic stenosis (AS), the most frequent heart valve disorder in developed countries, leads to the calcification and fibrous thickening of the valve. While several studies have addressed the process of valvular calcification, the molecular pathomechanisms of the extensive matrix remodeling remain unclear. Because inflammation is present in stenotic valves, we hypothesized that the proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) might influence cell proliferation and regulate the expression and activation of matrix metalloproteinases (MMPs)--enzymes that are thought to be involved in calcific AS.

METHODS

Immunohistochemistry for leukocytes, TNFalpha, MMP-1, and the endogenous MMP inhibitor tissue inhibitor of metalloproteinase (TIMP)-1 was performed on human stenotic (n = 19) and control (n = 8) valves. Primary cultures of human aortic valve myofibroblasts were incubated with and without TNFalpha, and cell proliferation was assessed. The expression and activation of MMP-1 were detected by Western blotting and a specific MMP-1 activity assay.

RESULTS

Control valves showed scattered macrophages and low expression of TNFalpha, MMP-1, and TIMP-1. In stenotic valves, leukocyte infiltration and a strong, colocalized expression of TNFalpha and MMP-1 were present, while TIMP-1 remained unchanged. Double-label immunofluorescence localized TNFalpha mainly to macrophages. In cultured human aortic valve myofibroblasts, TNFalpha stimulated proliferation and induced a time-dependent increase in MMP-1 expression and activation, while TIMP-1 remained unchanged.

CONCLUSION

The results indicate that matrix remodeling in calcific AS involves the expression and activation of MMPs. Activated leukocytes, by the secretion of TNFalpha, may stimulate valvular myofibroblasts to proliferate and express MMPs, thus regulating actively the matrix remodeling in calcific AS.

Asymptomatic valvular disease: who benefits from surgery?

Routine physical examination and noninvasive imaging frequently lead to the diagnosis of valvular heart disease in asymptomatic patients. The decision to proceed to surgical repair or replacement is based on an informed evaluation of the risks of surgery versus those encountered with a nonoperative course. In determining whether symptoms are present, stress testing may be helpful, as many patients with significant valvular lesions have a tendency to limit their daily physical exertion to levels that do not provoke symptoms. The two most feared consequences of conservative management, sudden death and permanent myocardial damage, are rare in asymptomatic patients with severe aortic stenosis or regurgitation. Surgery for asymptomatic aortic stenosis is performed only for certain high-risk subsets of patients, including those with left ventricular dysfunction, ventricular arrhythmia, and critically small valves. Asymptomatic patients with aortic regurgitation and mitral regurgitation should undergo surgery if they have systolic dysfunction or marked ventricular enlargement.

Trypanosoma cruzi trans-sialidase as a new therapeutic tool in the treatment of chronic inflammatory diseases: possible action against mycoplasma and chlamydia

The present paper proposes a new therapy using Trypanosoma cruzi trans-sialidase to treat diseases with unclear pathogenesis that present in common chronic inflammation and fibrosis. This hypothesis is based on recent findings that co-infection with mycoplasma and chlamydia is present in many of these diseases and that this enzyme was capable to eliminate or decrease the co-infection from the host. We identified that mycoplasmas and chlamydias are present in atherosclerosis, aortic valve stenosis, dilated cardiomyopathy, chronic chagasic myocarditis and cancer. We hypothetized that mycoplasmal infection may induce immunodepression in the host, favoring proliferation of pre-existent chlamydial infection and that elimination of mycoplasma would lead to improvement of the immune system resistance and the control of chlamydial proliferation. Mycoplasma has a particular parasitic relationship with host cells, involving strong adherence of their membranes, making it extremely difficult to eradicate mycoplasmal infection from the host. A new therapeutic approach is suggested using one or more agents that prevent or inhibit the adherence of mycoplasma to host cell membranes by removing sialic acid residues and preventing oxidation of the cells. The use of a neuraminidase enzyme, particularly the T. cruzi trans-sialidase enzyme, associated with treatment using anti-oxidating agents is proposed. Preliminary experimental animal and laboratory tests showed good results. The proposal that trans-sialidase from T. cruzi is efficient in combating co-infection of mycoplasma and chlamydia is based, at least in part, on the observation that chagasic patients suffering from T. cruzi infection present less mycoplasma and chlamydia infection in their tissues. Also, a lower incidence of the diseases above described to be related to mycoplasma infection is observed in chagasic patients. It is also hypothesized that co-infection with mycoplasma and chlamydia may induce oxidation of the host cells. Anti-oxidants such as those present in plant extracts may also be used in the treatment. Other diseases such as chronic hepatitis, glomerulonephritis, Multiple Sclerosis, Alzheimer's Syndrome and idiopathic encephalitis are other examples of chronic diseases where mycoplasma and chlamydia might be present, as they have the characteristics of unknown etiology, persistent chronic inflammation and fibrosis.

Influence of receptor activator of nuclear factor kappa B on human aortic valve myofibroblasts

Calcific aortic valve stenosis, the main heart valve disease in the elderly, is based on progressive calcification and fibrous thickening of the valve. Several reports addressed the pathogenesis of tissue calcification in this disorder, but few data exist on the molecular mechanisms of the fibrosis and remodeling of the extracellular matrix. The cytokine "receptor activator of nuclear factor kappa B ligand" (RANKL), is expressed in stenotic aortic valves and involved in valvular calcification during calcific aortic valve stenosis. The present study aimed to assess the influence of RANKL on the molecular mechanisms of connective tissue remodeling. In an established cell culture model of primary human aortic valve myofibroblasts, stimulation with RANKL increased cell proliferation as compared to medium alone. Matrix metalloproteinase (MMP)-1 was detectable time-dependently in conditioned media from RANKL-stimulated cells, but absent in media from control cells. MMP-1 activity was increased by RANKL, as measured by collagenase activity assay. Zymography showed an increase in active MMP-2 in RANKL-stimulated cells. These results support the concept that MMPs are involved in the connective tissue remodeling during calcific aortic valve stenosis. RANKL might regulate this process by promoting cell proliferation and MMP expression and activation.

Aortic valve sclerosis relates to cardiovascular events in patients with hypertension (a LIFE substudy)

This study investigated whether aortic valve (AV) sclerosis was associated with traditional cardiovascular (CV) risk factors and CV events in hypertensive patients with electrocardiographic left ventricular (LV) hypertrophy, as previously demonstrated in the general population. AV sclerosis was associated with several CV risk factors and predicted CV events independently of prevalent CV disease and traditional CV risk factors, including LV mass and ejection fraction.

Aortic valve sclerosis is an echocardiographic indicator of significant coronary disease in patients undergoing diagnostic coronary angiography

Aortic valve sclerosis (AVS) is considered to be a manifestation of generalised atherosclerosis that involves the aortic valve. It has been associated with higher cardiovascular morbidity and mortality in a population-based study. This investigation used transthoracic echocardiography (TTE) to evaluate the prevalence and significance of AVS in 357 Chinese patients with suspected coronary artery disease (CAD). This work reveals that AVS is an independent echocardiographic predictor of significant CAD in such clinical setting (O.R.=3.18; 95% confidence interval 1.52-6.7; p=0.002). Other independent predictors include male gender, diabetes mellitus and hypertriglyceridemia. The predictive value of AVS for the presence of CAD is more prominent in females and in subjects aged <65 years. The recognition of AVS on TTE should alert the physicians to the possibility of underlying significant CAD, and further evaluation with aggressive management is indicated, even though no angiographic documentation is available.

Mechanisms of aortic valve calcification

The calcified aortic valve lesion develops in the setting of endothelial injury and inflammation and displays hallmarks of atherosclerosis, including lipids accumulation, matrix metalloproteinase activation, and interaction with renin-angiotensin system. Current evidence indicates that modification of atherosclerotic risk factors will slow the progression of aortic valve calcification, and valve risk factors should be addressed in all patients who have aortic valve calcification.

Quantitative assessment of aortic sclerosis using ultrasonic backscatter

BACKGROUND

The development of therapeutic interventions to prevent progressive valve damage is more likely to limit the progression of structural damage to the aortic valve with normal function (aortic sclerosis [ASC]) than clinically apparent aortic stenosis. Currently, the ability to appreciate the progression of ASC is compromised by the subjective and qualitative evaluation of sclerosis severity.

METHODS

We sought to reveal whether the intensity of ultrasonic backscatter could be used to quantify sclerosis severity in 26 patients with ASC and 23 healthy young adults. Images of the aortic valve were obtained in the parasternal long-axis view and saved in raw data format. Six square-shaped 11 x 11 pixel regions of interest were placed on the anterior and posterior leaflets, and calibrated backscatter values were obtained by subtracting the regions of interest in the blood pool from the averaged backscatter values obtained from the leaflets.

RESULTS

Mean ultrasonic backscatter values for sclerotic valves exceeded the results in normal valve tissue (16.3 +/- 4.4 dB vs 9.8 +/- 3.3 dB, P < .0001). Backscatter values were greater (22.0 +/- 3.5 dB) in a group of 6 patients with aortic stenosis. Within the sclerosis group, the magnitude of backscatter was directly correlated (P < .05) with a subjective sclerosis score, and with transvalvular pressure gradient. Mean reproducibility was 2.4 +/- 1.8 dB (SD) between observers, and 2.3 +/- 1.7 dB (SD) between examinations.

CONCLUSION

Measurement of backscatter from the valve leaflets of patients with ASC may be a feasible means of following the progression and treatment response of aortic sclerosis.

Induction of local angiotensin II-producing systems in stenotic aortic valves

OBJECTIVES

The purpose of this study was to investigate the expression of angiotensin II (Ang II)-producing enzyme systems in normal and stenotic aortic valves.

BACKGROUND

Chronic inflammation and fibrosis are involved in the pathogenesis of aortic stenosis (AS), but the detailed molecular mechanisms of this atherosclerosis-like process remain obscure. Angiotensin II, a powerful mediator of inflammation and fibrosis, may participate in AS progression.

METHODS

Stenotic aortic valves (n = 86) were obtained from patients undergoing valve replacement surgery, and control valves (n = 11) were obtained from patients undergoing cardiac transplantation. Angiotensin-converting enzyme (ACE) and mast cell (MC)-derived chymase were quantified by reverse-transcription polymerase chain reaction, autoradiography, and immunostaining. The MCs, macrophages, and T lymphocytes were detected by immunohistochemistry, and angiotensin II type 1 receptor (AT-1R) by autoradiography.

RESULTS

Compared with control valves, stenotic aortic valves showed a significant increase in both messenger ribonucleic acid (mRNA) (p = 0.001) and protein (p < 0.001) expression of ACE, which colocalized with macrophages. Similarly, the expression of AT-1R protein and chymase mRNA and protein was upregulated (p < 0.001), and the number of MCs was six-fold higher in stenotic than in normal valves. The MCs were associated with the calcified areas, and-in contrast to control valves-showed an increased degree of degranulation, a prerequisite for chymase secretion and action.

CONCLUSIONS

Angiotensin-converting enzyme and chymase, two Ang II-forming enzymes, are locally expressed in aortic valves, and owing to infiltration of macrophages and MCs, are further upregulated in stenotic valves. These novel findings, implicating chronic inflammation and an increased expression of local Ang II-forming systems, suggest that therapeutic interventions aiming at inhibiting these processes may slow AS progression.

Invasive measurements of pulse wave velocity correlate with the degree of aortic valve calcification and severity associated with matrix metalloproteinases in elderly patients with aortic valve stenosis

The aim of the present study was to assess the association between invasive PWV (pulse wave velocity), serum levels of MMPs (matrix metalloproteinases) and the echocardiographic severity and calcification score of degenerative AS (aortic stenosis). We enrolled 30 patients (16 males; age, 61.3±8.2 years) diagnosed with degenerative AS and an additional 30 age- and sex-matched control patients. Invasive PWV methods with a pigtail catheter and double-channel recording were performed in both groups in our catheterization laboratory. We scored the severity of calcification at the AV (aortic valve) during two-dimensional echocardiography. The association between the trans-valvular pressure gradient, the severity of calcification of the AV and the value of PWV were analysed. We also analysed the serum levels of MMP-9, MMP-3 and TIMP-1 (tissue inhibitor of metalloproteinases-1) in these patients. In the group with degenerative AS, mean AV pressure gradients (56.0 compared with 9.5 mmHg; P<0.001) and calcified AV scoring (3.3±1.2 compared with 2.1±0.9; P<0.001) were higher than in the control group. In addition, PWV was faster in the group with degenerative AS (15.5±3.8 compared with 8.0±2.7 m/s; P=0.001). After being adjusted for age, sex, mean blood pressure and left ventricular function, both the AV pressure gradient and the severity of calcification were strongly correlated with PWV (R=0.706, P<0.0001, and R=0.561, P=0.03 respectively). In addition, the serum levels of MMP-9, MMP-3 and TIMP-1 were all significantly higher and correlated with PWV in the group with AS (all P<0.05). With higher serum levels of MMPs and their inhibitors, we found that this invasive measurement of PWV was associated strongly with the pressure gradient and calcification of AV. More advanced degenerative changes in AV was probably associated with more severe aortic arteriosclerosis.

Relation of aortic valve sclerosis to carotid artery intima-media thickening in healthy subjects

We studied 252 healthy adults by echocardiography and carotid ultrasonography to determine the relation between early subclinical aortic valve sclerosis (AVS) and carotid intima-media thickness (IMT). Carotid IMT was significantly greater in subjects with AVS than in those without AVS. There was a significant correlation between the grade of AVS and carotid IMT.

Hyperlipidaemia and aortic valve disease

PURPOSE OF REVIEW

Degenerative aortic valve stenosis is a common disease in the elderly, and traditional risk factors for atherosclerotic disease including hyperlipidaemia have been associated with the condition in several studies. This review addresses the role of the various risk factors and the potential for intervention.

RECENT FINDINGS

The association of lipid abnormalities such as high lipoprotein(a) levels and the presence of the apolipoprotein E4 allele with aortic stenosis, as well as the presence of several inflammatory markers both in plasma and in surgically excised valves, suggest that the stenotic process is driven by many of the same factors behind atherosclerosis. The aortic valves of animals fed a cholesterol-rich diet exhibit many characteristics in common with the early stages of aortic stenosis. This opens up the potential of retarding the process through intervention strategies.

SUMMARY

Hyperlipidaemia is associated with degenerative aortic valve stenosis, and the disease resembles the inflammatory process of atherosclerosis. Randomized controlled clinical trials will be needed to demonstrate the role of lipid intervention in patients with this condition.