Rationale, design, and baseline characteristics of a randomized trial to assess the effect of cholesterol lowering on the progression of aortic stenosis: the Aortic Stenosis Progression Observation: Measuring Effects of Rosuvastatin (ASTRONOMER) trial

Statins for the primary prevention of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) involves the formation of a blood clot in a vein, and includes deep venous thrombosis (DVT) or pulmonary embolism (PE). The annual incidence for VTE varies from 0.75 to 2.69 per 1000 individuals, with about 40 million people worldwide impacted by VTE. Statins, 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A (CoA) reductase inhibitors, inhibit cholesterol biosynthesis and display several vascular-protective effects, including antithrombotic properties. However, the potential role of statins in the primary prevention of VTE is still not clear.

OBJECTIVES

To evaluate the benefits and risks of statins in preventing venous thromboembolism (VTE) in individuals with no prior history of VTE.

SEARCH METHODS

We used standard Cochrane search methods. The search was last updated on 13 March 2023.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing statins with any control intervention (including placebo and usual care) in healthy individuals or participants with conditions other than VTE. There were no restrictions on the dose, duration, route, or timing of statins.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were VTE, DVT, and PE. Our secondary outcomes were serious adverse events, adverse events, and mortality. We used the trial sequential analysis (TSA) method to judge whether the evidence was sufficient, and we used the GRADE approach to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We included 27 RCTs involving 122,601 adults (aged 18 years and above) who were healthy, had various medical conditions (e.g. hypercholesterolemia), or were at risk for cardiovascular disease. Both males and females were included in all studies. Two studies focused solely on participants over 60 years of age. We deemed four studies to have a low risk of bias overall, while 19 were at high risk of bias, and four were unclear. The 27 studies compared use of statins versus placebo or usual care in individuals who had never experienced VTE. The statins used in the studies were atorvastatin, rosuvastatin, pravastatin, lovastatin, fluvastatin, and simvastatin. Twenty-three studies followed up participants for over a year, with six of those extending follow-ups for over five years. Twenty-five studies were based in hospitals, and 24 studies were funded by industry. Only one study used VTE as a primary endpoint. The median incidence of VTE in the statins group was 0.72% (ranging from 0% to 10.53%), and in the control group it was 0.89% (ranging from 0% to 6.83%). Our pooled analysis of the 27 studies showed that, relative to control groups, statins may slightly reduce the overall incidence of VTE (odds ratio (OR) 0.86, 95% confidence intervals (CI) 0.76 to 0.98; 27 studies, 122,601 participants; low-certainty evidence). Of the statins we evaluated, only rosuvastatin seemed to be associated with a reduced incidence of VTE, albeit the reduction in incidence was very small. The evidence did not clearly indicate a difference between groups in the incidence of DVT (OR 0.70, 95% CI 0.41 to 1.18; six studies, 40,305 participants; low-certainty evidence), PE (OR 0.83, 95% CI 0.46 to 1.52; five studies, 28,427 participants; low-certainty evidence), or myopathy (OR 1.10, 95% CI 0.83 to 1.45; 10 studies, 75,551 participants; low-certainty evidence). Nonetheless, statin use might slightly decrease the incidence of any serious adverse event (OR 0.95, 95% CI 0.91 to 0.99; 13 studies, 67,020 participants; low-certainty evidence) and any death (OR 0.90, 95% CI 0.86 to 0.95; 24 studies, 116,761 participants; low-certainty evidence), compared to control.

AUTHORS' CONCLUSIONS

Using statins for the primary prevention of VTE may slightly reduce the incidence of VTE and all-cause mortality. However, this effect is likely too weak to be considered significant. Statin use may not decrease the occurrence of DVT and PE. The current evidence is insufficient to draw strong conclusions because of the risk of bias in the studies, imprecision in the effect estimates, and potential publication bias. More evidence from well conducted and fully reported RCTs is needed to assess the preventive effects of different types of statins, as well as the effects of different dosages and treatment durations in various populations.

Statins for primary prevention of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is common in clinical practice. The efficacy of statins in the primary prevention of VTE remains unproven. This is an update of the review first published in 2011.

OBJECTIVES

To assess the efficacy of statins in the primary prevention of VTE.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases (PVD) Group Trials Search Co-ordinator searched the Specialised Register (last searched February 2014) and CENTRAL (2014, Issue 1).

SELECTION CRITERIA

Randomised controlled trials (RCTs) that assessed statins in the primary prevention of VTE were considered. The outcomes we evaluated were the rates of VTE, cardiovascular and cerebrovascular events, death and adverse events. Two authors (L Li, JH Tian) independently selected RCTs against the inclusion criteria. Disagreements were resolved by discussion with a third author (KH Yang).

DATA COLLECTION AND ANALYSIS

Data extraction was independently carried out by two authors (L Li, JH Tian). Disagreements were resolved by discussion with a third author (PZ Zhang). Two authors (L Li, JH Tian) independently assessed the risk of bias according to a standard quality checklist provided by the PVD Group.

MAIN RESULTS

For this update we included one RCT with 17,802 participants that assessed rosuvastatin compared with placebo for the prevention of VTE. The quality of the evidence was moderate because of imprecision, as the required sample size for the outcomes of this review was not achieved. Analysis showed that when compared with placebo rosuvastatin reduced the incidence of VTE (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.37 to 0.86) and deep vein thrombosis (DVT) (OR 0.45, 95% CI 0.25 to 0.79), the risk of any (fatal and non-fatal) myocardial infarction (MI) (OR 0.45, 95% CI 0.30 to 0.69), and any (fatal and non-fatal) stroke (OR 0.51, 95% CI 0.34 to 0.78). There was no difference in the incidence of pulmonary embolism (PE) (OR 0.77, 95% CI 0.41 to 1.46), fatal MI (OR 1.50, 95% CI 0.53 to 4.22), fatal stroke (OR 0.30, 95% CI 0.08 to 1.09) or death after VTE (OR 0.50, 95% CI 0.20 to 1.24). The incidence of any serious adverse events was no different between the rosuvastatin and placebo groups (OR 1.07, 95% CI 0.95 to 1.20).

AUTHORS' CONCLUSIONS

Available evidence showed that rosuvastatin was associated with a reduced incidence of VTE, but the evidence was limited to a single RCT and any firm conclusions and suggestions could be not drawn. Randomised controlled trials of statins (including rosuvastatin) are needed to evaluate their efficacy in the prevention of VTE.

Lipid-lowering efficacy of rosuvastatin

BACKGROUND

Rosuvastatin is one of the most potent statins and is currently widely prescribed. It is therefore important to know the dose-related magnitude of effect of rosuvastatin on blood lipids.

OBJECTIVES

Primary objective To quantify the effects of various doses of rosuvastatin on serum total cholesterol, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, non-HDL-cholesterol and triglycerides in participants with and without evidence of cardiovascular disease. Secondary objectives To quantify the variability of the effect of various doses of rosuvastatin.To quantify withdrawals due to adverse effects (WDAEs) in the randomized placebo-controlled trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) Issue 10 of 12, 2014 in The Cochrane Library, MEDLINE (1946 to October week 5 2014), EMBASE (1980 to 2014 week 44), Web of Science Core Collection (1970 to 5 November 2014) and BIOSIS Citation Index (1969 to 31 October 2014). No language restrictions were applied.

SELECTION CRITERIA

Randomized controlled and uncontrolled before-and-after trials evaluating the dose response of different fixed doses of rosuvastatin on blood lipids over a duration of three to 12 weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for studies to be included and extracted data. WDAEs information was collected from the placebo-controlled trials.

MAIN RESULTS

One-hundred and eight trials (18 placebo-controlled and 90 before-and-after) evaluated the dose-related efficacy of rosuvastatin in 19,596 participants. Rosuvastatin 10 to 40 mg/day caused LDL-cholesterol decreases of 46% to 55%, when all the trials were combined using the generic inverse variance method. The quality of evidence for these effects is high. Log dose-response data over doses of 1 to 80 mg, revealed strong linear dose-related effects on blood total cholesterol, LDL-cholesterol and non-HDL-cholesterol. When compared to atorvastatin, rosuvastatin was about three-fold more potent at reducing LDL-cholesterol. There was no dose-related effect of rosuvastatin on blood HDL-cholesterol, but overall, rosuvastatin increased HDL by 7%. There is a high risk of bias for the trials in this review, which would affect WDAEs, but unlikely to affect the lipid measurements. WDAEs were not statistically different between rosuvastatin and placebo in 10 of 18 of these short-term trials (risk ratio 0.84; 95% confidence interval 0.48 to 1.47).

AUTHORS' CONCLUSIONS

The total blood total cholesterol, LDL-cholesterol and non-HDL-cholesterol-lowering effect of rosuvastatin was linearly dependent on dose. Rosuvastatin log dose-response data were linear over the commonly prescribed dose range. Based on an informal comparison with atorvastatin, this represents a three-fold greater potency. This review did not provide a good estimate of the incidence of harms associated with rosuvastatin because of the short duration of the trials and the lack of reporting of adverse effects in 44% of the placebo-controlled trials.

Circulating levels of matrix gla protein and progression of aortic stenosis: a substudy of the Aortic Stenosis Progression Observation: Measuring Effects of rosuvastatin (ASTRONOMER) trial

BACKGROUND

Matrix γ-carboxyglutamate protein is an inhibitor of cardiovascular calcification. The objective of this substudy of the Aortic Stenosis Progression Observation: Measuring Effects of Rosuvastatin (ASTRONOMER) trial was to examine the relationship between total (ie, carboxylated [active] form + uncarboxylated [inactive] form) circulating desphosphorylated matrix γ-carboxyglutamate protein (dpMGP) level and the progression rate of aortic stenosis (AS).

METHODS

Among the patients included in the ASTRONOMER trial, 215 patients had measures of baseline circulating total dpMGP level and an echocardiographic follow-up (mean follow-up: 3.5 ± 1.3 years). Progression of AS was assessed according to the measurement of the annualized increase in peak aortic jet velocity.

RESULTS

In the whole cohort, baseline dpMGP level was associated with faster progression rate of peak aortic jet velocity (r = 0.16; P = 0.02) in individual analysis but not in multivariable analysis (P = 0.40). However, there was a significant interaction (P = 0.03) between dpMGP level and age, with respect to the effect on AS progression. After dichotomization according to median value of age (ie, 57 years old), total dpMGP level was associated with faster AS progression rate (r = 0.24; P = 0.008) in the younger patients, and this association remained significant in multivariable analysis (P = 0.04), but not in the older ones. The independent correlates of dpMGP level were fasting glucose (P = 0.009) and oxidized low-density lipoprotein (P = 0.01).

CONCLUSIONS

This is the first prospective study to demonstrate a relationship between increased circulating levels of total dpMGP and faster progression rate of AS in younger individuals. Future studies are needed to determine if dpMGP is simply a marker or a contributing factor to ectopic mineralization of aortic valve.

Asymptomatic Carotid Artery Disease in Valvular Heart Surgery

We evaluated the prevalence of asymptomatic carotid artery disease in patients scheduled for valvular cardiac surgery. Preoperative screening of the carotid arteries was performed. Among 1012 patients scheduled for valvular cardiac surgery, 267 (26.4%) had carotid stenosis graded >50%; 37 had carotid stenosis >70% and underwent combined valvular surgery and carotid endarterectomy (CEA); and 230 (86%) had carotid stenosis >50% to ≤69% and received valvular cardiac surgery under hypothermic cardiopulmonary bypass. Operative mortality and the rate of perioperative adverse neurological events were comparable among the groups. During 6.8 years of follow-up, patients with carotid stenosis not exceeding 69% at the time of surgery had CEA more frequently ( P < .05) and stroke/transient ischemic attack ([TIA] P < .05) versus patients treated with combined surgery. The prevalence of asymptomatic carotid stenosis is not negligible in patients undergoing isolated valvular surgery. Combined valvular and carotid surgery is safe and reduces the incidence of CEA and stroke/TIA during follow-up.

Effect of rosuvastatin on C-reactive protein and progression of aortic stenosis

BACKGROUND

Elevated C-reactive protein (CRP) is a common finding in patients with aortic stenosis (AS) and may be associated with rapid AS progression and worse outcome. The purpose of the study was to examine the role of high-sensitivity CRP and its interaction with rosuvastatin on the progression of AS.

METHODS

We measured CRP at baseline, 1 year, and end of follow-up in 260 patients with a median follow-up of 3.5 years. Analyses were performed based on baseline CRP tertiles and baseline CRP >3 and ≤3 mg/L.

RESULTS

After adjustment for baseline characteristics, higher CRP levels were associated with age, female gender, body mass index, and lower high-density lipoprotein cholesterol levels but not with AS severity. Treatment with rosuvastatin led to a persistent decrease in CRP at 1 year and end of follow-up. Progression of AS was detected in patients in all 3 CRP tertiles, and rosuvastatin treatment had no impact on progression in all 3 tertiles. Similar findings were observed using CRP >3 mg/L as the cutpoint. Multiple linear regression showed that baseline AS velocity (P < .001), but not CRP, was the only predictor of progression of AS; age (P = .05) and baseline AS velocity (P < .001), but not CRP and rosuvastatin treatment, were predictors of outcome events.

CONCLUSION

C-reactive protein does not predict severity, progression, and prognosis in patients with mild to moderate AS. Treatment with rosuvastatin reduces CRP levels but has no effect on the progression and clinical events of AS.

Effect of Lipid lowering with rosuvastatin on progression of aortic stenosis: results of the aortic stenosis progression observation: measuring effects of rosuvastatin (ASTRONOMER) trial

BACKGROUND

Aortic stenosis (AS) is an active process with similarities to atherosclerosis. The objective of this study was to assess the effect of cholesterol lowering with rosuvastatin on the progression of AS.

METHODS AND RESULTS

This was a randomized, double-blind, placebo-controlled trial in asymptomatic patients with mild to moderate AS and no clinical indications for cholesterol lowering. The patients were randomized to receive either placebo or rosuvastatin 40 mg daily. A total of 269 patients were randomized: 134 patients to rosuvastatin 40 mg daily and 135 patients to placebo. Annual echocardiograms were performed to assess AS progression, which was the primary outcome; the median follow-up was 3.5 years. The peak AS gradient increased in patients receiving rosuvastatin from a baseline of 40.8+/-11.1 to 57.8+/-22.7 mm Hg at the end of follow-up and in patients with placebo from 41.6+/-10.9 mm Hg at baseline to 54.8+/-19.8 mm Hg at the end of follow-up. The annualized increase in the peak AS gradient was 6.3+/-6.9 mm Hg in the rosuvastatin group and 6.1+/-8.2 mm Hg in the placebo group (P=0.83). Treatment with rosuvastatin was not associated with a reduction in AS progression in any of the predefined subgroups.

CONCLUSIONS

Cholesterol lowering with rosuvastatin 40 mg did not reduce the progression of AS in patients with mild to moderate AS; thus, statins should not be used for the sole purpose of reducing the progression of AS. Clinical Trial Registration Information- URL: http://www.controlled-trials.com/.

CLINICAL TRIAL REGISTRATION NUMBER

ISRCTN 32424163.

The bicuspid aortic valve and related disorders

Bicuspid aortic valve (BAV) is the most common congenital cardiac malformation, affecting 1-2% of the population, with strong male predominance. Individuals may have a normally functioning BAV, and may be unaware of its presence and the potential risk of complications. However, they may easily develop aortic valve disorders: either stenotic or regurgitant, or both. Today, BAV is recognized as a syndrome incorporating aortic valve disorders and aortic wall abnormalities, including aortic dilation, dissection or rupture. Congenital or hereditary diseases such as ventricular septal defect, patent ductus arteriosus, coarctation of the aorta, Turner's syndrome, Marfan's syndrome etc., may frequently be associated with BAV. Infective endocarditis and occasionally thrombus formation may develop during the lives of BAV patients. Elevated cholesterol or C-reactive protein may be seen in laboratory findings of these patients. Beta-blockers and statins are the possibilities for medical treatment, and aortic valve repair/replacement and ascending aorta replacement are indicated for patients with a severely diseased aortic valve and aorta. Rigorous follow-up throughout life is mandatory after BAV has been diagnosed. The aim of the present article was to describe the implications of BAV and its associated disorders, and to discuss diagnostic and treatment strategies.

Common pathogenic features of atherosclerosis and calcific aortic stenosis: role of transforming growth factor-beta

Calcific aortic stenosis and atherosclerosis have been investigated separately in experimental in vitro and in vivo studies and in clinical studies. The similarities identified in both diseases suggest that similar pathogenic pathways are involved in both conditions. Most current therapeutic studies are focused on statins. The evidence suggests that statin effects on valves may, in large part, be independent of the lipid lowering effects of the drug. There are several molecules that play significant regulatory roles on the development and progression of valve sclerosis and calcification and on growth and complications of atherosclerotic plaques. The purpose of this review is to discuss the pathogenic features of the two conditions, highlight the important similarities, and then review the data that suggest that transforming growth factor-beta may play a key regulatory role in both diseases and that this is worthy of study as a potential therapeutic target for both conditions.

Lipid lowering and aortic valve disease

Several retrospective and nonrandomized studies have indicated that lowering atherogenic lipoprotein, in particular low-density lipoprotein cholesterol, may retard the hemodynamic progression of aortic stenosis (AS). This valvular disease shares pathogenic and pathoanatomic similarities with atherosclerosis, at least in their early developments. Two randomized placebo-controlled studies researching the effect of lowering low-density lipoprotein on AS progression and its clinical consequences have been published recently-the Scottish Aortic Stenosis and Lipid Lowering Trial, Impact on Regression (SALTIRE) study and the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study. Both of these studies had neutral outcomes. The causes for the negative outcome may be that cholesterol lowering does not influence AS development in a clinically significant way or it may be due to traits in the design of the studies or treatments. Therefore, statin treatment for prevention of AS progression cannot be ruled out as a future therapeutic option in AS. The outcome of the ongoing Aortic Stenosis Progression Observation: Measuring Effects of Rosuvastatin (ASTRONOMER) study, which is examining lipid lowering as a treatment for AS, is greatly anticipated.

Statins block calcific nodule formation of valvular interstitial cells by inhibiting alpha-smooth muscle actin expression

OBJECTIVE

Calcific aortic stenosis, characterized by excessive fibrosis and deposition of bone-like calcified tissue, affects roughly 2% to 3% of the U.S. population over the age of 65. Recent studies have suggested that statins have a positive effect on the progression of aoritic stenosis, likely because of their ability to affect the resident cell population, known as valvular interstitial cells (VICs). VICs are fibroblastic cells that can differentiate to form activated myofibroblasts, displaying increased alpha smooth muscle actin (alphaSMA) expression, contractility, and collagen production.

METHODS AND RESULTS

In culture, VICs spontaneously form multicellular aggregates that subsequently develop into calcified nodules, providing an in vitro model for aortic stenosis. Using real-time microscopic tracking, we observed that confluent VIC monolayers spontaneously contract into rounded nodules, suggesting that myofibroblastic contractility is a critical step in the process of nodule formation. Overexpression of alphaSMA increased VIC calcific nodule formation and contractility, whereas knockdown of alphaSMA with siRNAs reduced these phenotypes, suggesting that the expression and contractile properties of alphaSMA are essential to the formation of nodules. Statin treatment of VICs reduced alphaSMA expression, inhibited contractility, and decreased nodule formation. When statins were used to treat preformed nodules, no decrease in the number of calcified nodules was observed, suggesting that statins may play more of a preventative role in aortic stenosis than a cure.

CONCLUSIONS

Our studies provide evidence of a causal relationship between VIC myofibroblastic activity and initial VIC calcific nodule formation. Furthermore, we demonstrate that pravastatin inhibition of calcific nodule formation is related to inhibition of myofibroblastic activity.

Prevention of calcific aortic valve stenosis-fact or fiction?

Valve replacement is the only long-term effective treatment for calcific aortic valve stenosis. However, this treatment is aimed only at patients with advanced leaflet disease and symptoms of left ventricular obstruction. Over the past 15 years, our understanding of the pathogenesis of calcific aortic stenosis has changed significantly: away from a passive degenerative disease to an active process involving endothelial dysfunction, lipid accumulation, an inflammatory infiltrate, and a regulated process of calcification. Since many of the same processes are characteristic of atherosclerosis, trials have been undertaken to test whether medical therapy (statins, renin-angiotensin inhibition) can prevent or alter the disease course. Although retrospective and non-randomized studies suggested a positive effect with statins, benefit has not been seen in perspective randomized controlled trials, although two major studies are still in progress. Inhibition of renin-angiotensin has shown discordant results in retrospective studies with no randomized controlled data published. In the future, we need to consider other medical therapies that might target different pathways in this disease process. In addition, we need to define the optimal timing and duration of therapy for this chronic slowly progressive disease; treatments aimed at the early disease process may be ineffective with end-stage tissue changes.

Intensive lipid-lowering therapy for patients with aortic stenosis

It has been suggested by several retrospective studies that lipid-lowering therapy (compared with treatment with medications other than statins) retards the progression of aortic stenosis. Additional evidence for this has emerged from the prospective (nonrandomized) Rosuvastatin Affecting Aortic Valve Endothelium (RAAVE) study, although not from findings of the randomized, double-blind Scottish Aortic Stenosis and Lipid Lowering Trial, Impact on Regression (SALTIRE). Currently, 2 larger randomized studies of aortic stenosis are in progress. These studies have longer durations than SALTIRE. The Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, with 1,873 patients, is the largest study with the longest planned length of treatment (4 to 7 years) that will assess whether lipid-lowering therapy slows the progression of aortic stenosis and the degradation of the aortic valve, thereby potentially reducing the urgency for surgery or at least delaying the need for surgery, relieving adverse hemodynamic consequences of aortic stenosis, and possibly decreasing mortality and morbidity in these patients. The Aortic Stenosis Progression Observation: Measuring Effects of Rosuvastatin (ASTRONOMER) trial, a study of disease progression, involves 272 patients with aortic stenosis, with treatment arms of rosuvastatin 40 mg/d and placebo for 3 to 5 years. In conclusion, the SEAS and ASTRONOMER studies will help resolve the contradictory findings of SALTIRE and RAAVE on the benefit of intensive lipid-lowering treatment in aortic stenosis.

Atherosclerotic inflammation triggers osteogenic bone transformation in calcified and stenotic human aortic valves: still a matter of debate

Sclerotic calcification of the aortic valve is a common disease in advanced age. However, pathophysiologic processes leading to valve calcifications are poorly understood. Transformation of atherosclerotic triggers to osteogenic differentiation is controversially discussed and is thought as a trigger of bone transformation in end stage disease. This study focuses on the transcriptional gene-profiling of severe calcified stenotic human aortic valves to clarify the molecular basis of the pathophysiological process. We collected severely calcified and stenotic human aortic valves (CSAV) with (CSAV+, n=10) and without (CSAV-, n=10) at least 4 weeks of statin pre-treatment prior to valve replacement and investigated transcriptional steady-state gene-profiling by using micro array technique and GAPDH-adjusted PCR for confirmation. Results were compared with findings in non-sclerotic aortic valves: C (n=6). Various parameters of inflammation were significantly up regulated as compared to C: eotaxin3, monokine induced by gamma-interferon, vascular adhesion protein-1 (VAP-1), peroxisome proliferative activated receptor-alpha or transforming growth factor beta 1 (TGF beta 1). Except for TGF beta 1 and VAP-1, statin pre-treatment neutralized altered gene expression. Genes of osteogenic bone transformation (tenascin C, bone sialoprotein, Cbfa1, Osteocalcin, Beta-catenin, Sox- and Cyclin-genes) were found unaltered in their expression in both, CSAV- or CSAV+ in comparison to C. This study shows continuing atherosclerotic inflammation on CSAV. Additionally, no evidence of initiated osteoblastic differentiation process was found. Pre-treatment of patients with statins partially neutralized the gene pattern of inflammation on the aortic valves. This suggests that there are potent benefits of statins on early development of inflammation on calcified aortic valves.

Stage-related effect of statin treatment on the progression of aortic valve sclerosis and stenosis

It has been suggested that statins could slow the progression of aortic stenosis (AS), but this hypothesis is still debated and has not been validated in large series of patients by long-term follow-up studies. Moreover, information about the role of statins in patients with different degrees of severity of AS is scarce. From our 1988 to 2007 echocardiographic database, we retrospectively identified all asymptomatic patients with aortic valve sclerosis (abnormal irregular thickening of the aortic valve with a peak aortic velocity [Vmax] > or =1.5 and <2 m/s), mild AS (Vmax > or =2 and <3 m/s), and moderate AS (Vmax > or =3 and <4 m/s), age > or =50 years, and with > or =2 echocardiographic studies > or =2 years apart. Exclusion criteria were moderate/severe aortic regurgitation, bicuspid aortic valve, rheumatic valve disease, and ejection fraction <40%. The final study population consisted of 1,046 patients (mean age 70 +/- 8 years, 587 men); 309 were treated with statins. Mean follow-up duration was 5.6 +/- 3.2 years (range 2 to 19). Progression of AS was slower in patients receiving statins compared with untreated patients in aortic sclerosis (0.04 +/- 0.09 vs 0.07 +/- 0.10 m/s/year, p = 0.01) and mild AS (0.09 +/- 0.15 vs 0.15 +/- 0.15 m/s/year, p = 0.001), but not in moderate AS (0.21 +/- 0.18 vs 0.22 +/- 0.15 m/s/year, p = 0.70). In multivariate analysis only statin therapy, initial Vmax, and dialysis were independently related to progression of aortic valve disease. In conclusion, in a large series of patients with long-term follow-up, statins were effective in slowing the progression of aortic valve disease in aortic sclerosis and mild AS, but not in moderate AS. These results suggest that statin therapy should be taken into consideration in the early stages of this common disease.

Review: Does lowering cholesterol have an impact on the progression of aortic stenosis?

Several studies suggest that atherosclerotic disease is not a focal disease restricted to culprit lesions in the intima of the arterial wall, but seems to act as a general disease affecting the entire cardiovascular system. Evolving research has lately focused on the atherosclerotic component in calcific aortic stenosis (AS) as it seems that the valve is affected in a pattern similar to that of the vasculature. The hope is therefore, that we someday in the management of patients with calcific AS can apply some of the same treatment strategies as in atherosclerotic vascular disease. This article reviews the pathophysiological mechanisms of calcific AS, reviews current clinical trials of statin use in aortic stenosis and reports on on-going trials, evaluating whether cholesterol lowering therapy can slow disease progression in different populations. Finally, we review if computerized tomography, biomarkers, and clinical characteristics such as left ventricular ejection fraction, can be useful in stratifying patients to potential benefit of statin therapy.

Established and emerging vascular risk factors and the development of aortic stenosis: an opportunity for prevention?

BACKGROUND

Aortic stenosis (AS) is the commonest valvular heart disease in the developed world. It is becoming increasingly accepted that the pathogenesis of AS and of its preceding abnormalities, aortic valve sclerosis (AVS) and aortic valve calcification (AVC), shares many characteristics with the atherosclerotic process.

OBJECTIVE

To assess the contribution of established and emerging vascular risk factors in the development of AS and to evaluate the potential of pharmacological intervention to modify the natural history of AS.

METHODS

We reviewed the epidemiological data that link AS and atherosclerosis and studies of vasculoprotective agents in patients with AS.

RESULTS/CONCLUSIONS

AS, AVS and AVC share many common risk factors with atherosclerosis and are possible markers of preclinical vascular disease. Statins appear to delay the progression of AS. However, more studies are needed before introducing such pharmacologic treatment for AS. The future may point towards targeted prevention of AS.

Aortic sclerosis, aortic stenosis and lipid-lowering therapy

Calcific aortic stenosis (AS) is a progressive disease that has, until recently, been considered to be a degenerative and unmodifiable process induced by long-lasting mechanical stress. However, histopathologic studies have now demonstrated that the development and progression of calcific AS is based on an active process, sharing a number of similarities with atherosclerosis. Inflammation, lipid infiltration, dystrophic calcification, ossification, platelet deposition and endothelial dysfunction have been observed in both diseases. In addition, several studies have suggested that AS and atherosclerosis share a number of risk factors, such as hypercholesterolemia, elevated lipoprotein (a), smoking, hypertension and diabetes. These findings suggest that statin therapy could be beneficial in AS by its lipid-lowering and/or anti-inflammatory effects, as is the case in atherosclerosis. Although this concept has been supported by experimental work and by four retrospective clinical studies observing significantly slower rates of hemodynamic progression in statin-treated patients, a prospective randomized trial (Scottish Aortic Stenosis and Lipid Lowering Trial, Impact on Regression [SALTIRE]; 80mg of atorvastatin vs placebo) yielded a negative result. In contrast to the retrospective analyses, according to the study protocol, patients with hyperlipidemia had to be excluded in this trial. A recent prospective study (Rosuvastatin Affecting Aortic Valve Endothelium [RAAVE]) treating hypercholesteremic patients with rosuvastatin, found a significantly slower rate of progression in these patients compared with patients with normal cholesterol levels who were left untreated, suggesting that statin therapy may only be beneficial in patients with hyperlipidemia. Lipid-lowering therapy with statins can, therefore, currently only be recommended in this subgroup of patients with AS.

Evaluation and management of aortic valve and root disease

Aortic valve disease manifests in the form of stenosis, regurgitation, or some combination, yielding either excessive afterload and/or excessive preload on the left ventricle. Aortic root disease may affect valvular function, causing regurgitation; may simply be coexistent with stenotic aortic valvular disease; or may exist despite normal aortic valve function. Indications for intervening on aortic valve or root disease are determined by the presence of symptoms, by the pathology's impact on left ventricular function, or by the inherent risk of aortic catastrophe (dissection, disruption, or sudden death). Aortic valvular and root diseases are primarily treated by surgical replacement of the pathologic structures. Mechanical aortic valve replacement has long-term durability but requires continuous anticoagulation. Bioprostheses do not require anticoagulation but have more limited durability. Valve-sparing aortic root replacement and aortic valve repair offer the potential for indefinite durability without the need for anticoagulation but are technically more difficult to perform and require more stringent selection criteria based on determining the reparability of an aortic valve. Emerging percutaneous valve technologies offer new hope for patients who are not candidates for aortic valve surgery, but the applicability and durability of percutaneous aortic valves are not yet known. Timely and appropriate intervention in aortic valve and root disease can result in the restoration of a normal life span for patients with aortic valvular and/or root disease.

Timing of operation in asymptomatic severe aortic stenosis

Calcific aortic stenosis is now the main cause of aortic stenosis in the majority of patients, due to declining incidence of rheumatic fever. Risk factors such as hyperlipidemia play an important role in the progression of aortic stenosis. According to the most recent American College of Cardiology/American Heart Association guidelines, peak velocity greater than 4 m/sec, a mean gradient of more than 40 mmHg and a valve area of less than 1.0 cm(2) is considered hemodynamically severe aortic stenosis. Aortic valve surgery promptly should be done in symptomatic patients due to dismal prognosis without operation. Features such as high aortic valve calcium and positive exercise test identify asymptomatic patients who would benefit from early aortic valve surgery. Due to improvement in surgical techniques and better prosthesis, aortic valve surgery can now be offered at low risk to a selected group of asymptomatic patients with severe aortic stenosis. Currently percutaneous aortic valves are used in very high-risk patients with severe symptomatic aortic stenosis. Their role may expand in the future, depending on the improvements in design and operator experience. Whether advances in molecular cardiology lead to novel therapies in preventing calcific aortic stenosis in the future remains to be seen.

Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest will be abstracted monthly regarding a broad scope of topics.