| Aortic stenosis | |
|---|---|
 | |
| In the center anaortic valve with severe stenosis due torheumatic heart disease. The valve is surrounded by theaorta. Thepulmonary trunk is at the upper right. Theright coronary artery, cut lengthwise, is at the lower left. Theleft main coronary artery, also cut lengthwise, is on the right. | |
| Specialty | Cardiothoracic surgery |
| Symptoms | Decreased ability to exercise,loss of consciousness,shortness of breath,heart related chest pain,leg swelling[1] |
| Complications | Heart failure[1] |
| Usual onset | Gradual[1] |
| Causes | Bicuspid aortic valve,rheumatic fever[1] |
| Risk factors | Smoking,high blood pressure,high cholesterol,diabetes, being male[1] |
| Diagnostic method | Ultrasound of the heart[1] |
| Treatment | Aortic valve replacement,balloon aortic valvuloplasty[1] |
| Prognosis | Five-year survival ~50% without treatment in symptomatic patients[1] |
| Frequency | 2% of people over 65 (developed world)[1] |
Aortic stenosis (AS orAoS) is thenarrowing of the exit of theleft ventricle of theheart (where theaorta begins), such that problems result.[1] It may occur at theaortic valve as well as above and below this level.[1] It typically gets worse over time.[1] Symptoms often come on gradually, with a decreased ability to exercise often occurring first.[1] Ifheart failure,loss of consciousness, orheart related chest pain occur due to AS the outcomes are worse.[1] Loss of consciousness typically occurs with standing or exercising.[1] Signs of heart failure includeshortness of breath especially whenlying down,at night, or with exercise, andswelling of the legs.[1] Thickening of the valve without causing obstruction is known asaortic sclerosis.[1]
Causes include being born with abicuspid aortic valve, andrheumatic fever; a normal valve may also harden over the decades due tocalcification.[2][1] A bicuspid aortic valve affects about one to two percent of the population.[1] As of 2014 rheumatic heart disease mostly occurs in thedeveloping world.[1] Risk factors are similar to those ofcoronary artery disease and includesmoking,high blood pressure,high cholesterol,diabetes, and being male.[1] The aortic valve usually has three leaflets and is located between the left ventricle of the heart and the aorta.[1] AS typically results in aheart murmur.[1] Its severity can be divided into mild, moderate, severe, and very severe, distinguishable byultrasound scan of the heart.[1]
Aortic stenosis is typically followed up with repeated ultrasound scans.[1] Once it has become severe, treatment primarily involvesvalve replacement surgery, withtranscatheter aortic valve replacement (TAVR) being an option in some who are at high risk from surgery.[1] Valves may either bemechanical orbioprosthetic, with each having risks and benefits.[1] Another less invasive procedure,balloon aortic valvuloplasty (BAV), may result in benefit, but for only a few months.[1] Complications such as heart failure may be treated in the same way as in those with mild to moderate AS.[1] In those with severe disease several medications should be avoided, includingACE inhibitors,nitroglycerin, and somebeta blockers.[1]Nitroprusside orphenylephrine may be used in those withdecompensated heart failure depending on the blood pressure.[1][3]
Aortic stenosis is the most commonvalvular heart disease in thedeveloped world.[4] It affects about 2% of people who are over 65 years of age.[1] Estimated rates were not known in most of the developing world as of 2014.[5] In those who have symptoms, without repair the chance of death at five years is about 50% and at 10 years is about 90%.[1] Aortic stenosis was first described by French physician Lazare Rivière in 1663.[6]
Symptoms related to aortic stenosis depend on the degree of stenosis. Most people with mild to moderate aortic stenosis do not have symptoms. Symptoms are usually present in individuals with severe aortic stenosis, though they may also occur in those with mild to moderate aortic stenosis. The three main symptoms of aortic stenosis areloss of consciousness,anginal chest pain andshortness of breath with activity or other symptoms of heart failure such asshortness of breath while lying flat,episodes of shortness of breath at night, orswollen legs and feet.[4][7] It may also be accompanied by the characteristic "Dresden china" appearance ofpallor with a lightflush.[8][clarification needed]
Angina in the setting of heart failure also increases the risk of death. In people with angina, the 5-year mortality rate is 50% if the aortic valve is not replaced.[9]
Angina in the setting of AS occurs due toleft ventricular hypertrophy (LVH) that is caused by the constant production of increased pressure required to overcome the pressure gradient caused by the AS. While themuscular layer of the left ventricle thickens, the arteries that supply the muscle do not get significantly longer or bigger, so the muscle may not receive enough blood supply to meet its oxygen requirement. Thisischemia may first be evident during exercise when the heart muscle requires increased blood supply to compensate for the increased workload. The individual may complain of anginal chest pain with exertion. Exercise stress testing with or without imaging is strictly contraindicated in symptomatic patients with severe aortic stenosis. Exercise stress test is now recommended by current guidelines in asymptomatic patients and may provide incremental prognostic value.[10]
Eventually, however, the heart muscle will require more blood supply at rest than can be supplied by thecoronary artery branches. At this point there may be signs ofventricularstrain pattern (ST segment depression and T wave inversion) on theEKG, suggesting subendocardial ischemia. The subendocardium is the region that is most susceptible to ischemia because it is the most distant from the epicardial coronary arteries.[11]
Syncope (fainting spells) from aortic valve stenosis is usually exertional.[4][12] In the setting of heart failure it increases the risk of death. In people with syncope, the three-year mortality rate is 50% if the aortic valve is not replaced.[13]
It is unclear why aortic stenosis causes syncope. One theory is that severe AS produces a nearly fixedcardiac output.[14] When a person with aortic stenosis exercises, theirperipheral vascular resistance will decrease as the blood vessels of theskeletal muscles dilate to allow the muscles to receive more blood to allow them to do more work. This decrease in peripheral vascular resistance is normally compensated for by an increase in the cardiac output. Since people with severe AS cannot increase their cardiac output, the blood pressure falls and the person will faint due to decreased blood perfusion to thebrain.[15]
A second theory is that during exercise, the high pressures generated in the hypertrophied left ventricle cause a vasodepressor response, which causes a secondary peripheralvasodilation that, in turn, causes decreased blood flow to the brain, resulting in loss of consciousness. Indeed, in aortic stenosis, because of the fixed obstruction to blood flow out from the heart, it may be impossible for the heart to increase its output to offset peripheral vasodilation.[citation needed]
A third mechanism may sometimes be operative. Due to the hypertrophy of theleft ventricle in aortic stenosis, including the consequent inability of thecoronary arteries to adequately supply blood to themyocardium (see "Angina" below),abnormal heart rhythms may develop. These can lead to syncope.[16]
Finally, in calcific aortic stenosis[17][18] at least, the calcification in and around the aortic valve can progress and extend to involve theelectrical conduction system of the heart. If that occurs, the result may beheart block, a potentially lethal condition of which syncope may be a symptom.[citation needed]
Congestive heart failure (CHF) carries a grave prognosis in people with AS. People with CHF attributable to AS have a 2-year mortality rate of 50% if the aortic valve is not replaced.[citation needed] CHF in the setting of AS is due to a combination ofleft ventricular hypertrophy with fibrosis, systolic dysfunction (a decrease in theejection fraction) anddiastolic dysfunction (elevated filling pressure of the LV).[4]
InHeyde's syndrome, aortic stenosis is associated withgastrointestinal bleeding due toangiodysplasia of thecolon.[19] Recent research has shown that the stenosis causes a form ofvon Willebrand disease by breaking down its associatedcoagulation factor (factor VIII-associated antigen, also calledvon Willebrand factor),[20] due to increased turbulence around the stenotic valve.
Notwithstanding the foregoing[clarification needed], theAmerican Heart Association changed its recommendations regarding antibiotic prophylaxis forendocarditis. Specifically, as of 2007, it is recommended that such prophylaxis should be limited only to those with prosthetic heart valves, those with previous episode(s) of endocarditis, and those with certain types of congenital heart disease.[21]
Since the stenosed aortic valve may limit the heart's output, people with aortic stenosis are at risk of syncope and dangerously low blood pressure should they use any of a number of medications for cardiovascular diseases that often coexist with aortic stenosis. Examples includenitroglycerin,nitrates,ACE inhibitors,terazosin (Hytrin), andhydralazine. Note that all of these substances lead to peripheralvasodilation. Under normal circumstances, in the absence of aortic stenosis, the heart is able to increase its output and thereby offset the effect of the dilated blood vessels. In some cases of aortic stenosis, however, due to the obstruction of blood flow out of the heart caused by the stenosed aortic valve,cardiac output cannot be increased. Low blood pressure or syncope may ensue.[citation needed]
Aortic stenosis is most commonly caused by age-related progressivecalcific aortic valve disease (CAVD) (>50% of cases), with a mean age of 65 to 70 years. CAVD is thebuild-up of calcium on the cusps of the valve, and thiscalcification causes hardening and stenosis of the valve.[22] Another major cause of aortic stenosis is the calcification of a congenitalbicuspid aortic valve or, more rarely, a congenital unicuspid aortic valve. Those with unicuspid aortic valves typically need intervention when very young, often as a newborn, while those with congenital bicuspid aortic valve make up 30-40% of those presenting during adulthood[23] and typically present earlier (ages 40+ to 50+) than those with tricuspid aortic valves (65+).[7]
Acute rheumatic fever post-inflammatory is the cause of less than 10% of cases.[24] Rare causes of aortic stenosis includeFabry disease,systemic lupus erythematosus,Paget disease,high blood uric acid levels, andinfection.[25]
The humanaortic valve normally consists of three cusps or leaflets and has an opening of 3.0-4.0 square centimeters.[6][25] When the left ventricle contracts, it forces blood through the valve into the aorta and subsequently to the rest of the body. When the left ventricle expands again, the aortic valve closes and prevents the blood in the aorta from flowing backward (regurgitation) into the left ventricle. In aortic stenosis, the opening of the aortic valve becomes narrowed or constricted (stenotic) (e.g., due to calcification). Degenerative (the most common variety) and bicuspid aortic stenosis both begin with damage toendothelial cells from increased mechanical stress.[7][25] Inflammation is thought to be involved in the earlier stages of the pathogenesis of AS and its associated risk factors are known to promote the deposition ofLDL cholesterol andlipoprotein(a), a highly damaging substance, into the aortic valve, causing significant damage and stenosis over time.[7][25] Infiltration of inflammatory cells (macrophages, T lymphocytes), followed by the release of inflammatory mediators such as interleukin-1-beta and transforming growth factor beta-1 occurs.Subsequently, fibroblasts differentiate into osteoblast-like cells, which results in abnormal bone matrix deposition leading to progressive valvular calcification and stenosis.[26]
As a consequence of this stenosis, the left ventricle must generate a higher pressure with each contraction to effectively move blood forward into the aorta.[4][27] Initially, the LV generates this increased pressure by thickening its muscular walls (myocardial hypertrophy). The type of hypertrophy most commonly seen in AS is known as concentric hypertrophy,[4] in which the walls of the LV are (approximately) equally thickened.
In the later stages, the left ventricle dilates, the wall thins, and the systolic function deteriorates (resulting in impaired ability to pump blood forward). Morris and Innasimuthu et al. showed that different coronary anatomy is associated with different valve diseases. Research was in progress in 2010 to see if different coronary anatomy might lead to turbulent flow at the level of valves, leading to inflammation and degeneration.[28][29][30]
Degenerative aortic valve stenosis represents the most common etiology of aortic stenosis (AS), particularly among elderly populations in industrialized nations. The pathophysiology involves fibrotic and calcific remodeling of the valve, characterized by excesscollagen deposition and disorganization.Transforming growth factor-β (TGF-β) plays a crucial role in this process by stimulatingextracellular matrix formation. The prevalence of degenerative AS has significantly increased due to population aging, making it the most frequent cause of heart valve replacement in developed countries.Valve interstitial cells (VICs) undergo osteogenic differentiation (changing their cell types into bone-formingosteoblasts), facilitated by factors including hemodynamic stress,reactive oxygen species, andinflammatory cytokines, leading to progressivecalcification of the valve tissue.[31]
Bicuspid aortic valve represents the most common congenital valve defect causing AS, with a prevalence of approximately 0.5-1% in children. Patients with bicuspid valves typically develop degenerative AS earlier than those with tricuspid valves. The abnormal valve architecture alters hemodynamic stress patterns across the valve surface, accelerating degenerative processes. These patients often develop symptomatic disease at younger ages compared to those with trileaflet valves affected by age-related degenerative processes.[31]
Rheumatic heart disease, a systemic inflammatory condition resulting from untreatedgroup A streptococcal infection, historically represented a significant cause of AS. However, its prevalence has markedly decreased in developed nations due to improved antibiotic availability. The pathophysiology involves immune-mediated damage to the valve tissue following streptococcal infection, resulting in scarring, commissural fusion, and subsequent calcification.[31]
Lipid accumulation in aortic valves contributes significantly to valvular calcification by promoting osteogenic differentiation of VICs. Oxidized lipids mediate this process viabone morphogenetic protein-2 (BMP2) induction, which upregulates osteogenic pathways involving transcription factors such asmsh homeobox 2 (Msx2) andRunx2/Cbfa1. TheWnt signaling pathway, activated by thelow-density lipoprotein receptor protein-5 (LRP5), is overexpressed in stenotic aortic valves and drives osteogenic differentiation. This lipid-mediated calcification shares many features with atherosclerosis, including oxidative stress patterns that generate reactive oxygen species that further promote BMP2 expression and osteogenic programming.[31]
Inflammatory processes significantly contribute to AS development through multiple pathways. Oxidized lipids activate innate immune responses viatoll-like receptors (TLRs) and thenuclear factor-κB (NF-κB) pathway, promoting osteogenic phenotypes in VICs.Interleukin-6 (IL-6), which is increased in calcified aortic valves, promotes mineralization of valve leaflets through BMP2 expression and induces receptor activator of NF-κB ligand (RANKL), further stimulating extracellular matrix production by VICs. This inflammatory cascade creates a self-perpetuating cycle that accelerates valve calcification and stenosis progression.[31]
Aortic stenosis is most often diagnosed when it isasymptomatic and can sometimes be detected during routine examination of the heart and circulatory system. Good evidence exists to demonstrate that certain characteristics of the peripheral pulse can rule in the diagnosis.[32] In particular, there may be a slow and/or sustained upstroke of the arterial pulse, and the pulse may be of low volume. This is sometimes referred to aspulsus parvus et tardus.[12][24] There may also be a noticeable delay between thefirst heart sound (onauscultation) and the corresponding pulse in thecarotid artery ('apical-carotid delay'). In a similar manner, there may be a delay between the appearance of each pulse in the brachial artery (in the arm) and the radial artery (in the wrist).[citation needed]
The first heart sound may be followed by a sharp ejection sound ("ejection click") best heard at thelower left sternal border and the apex, and thus, appears to be "split". The ejection sound, caused by the impact of left ventricular outflow against the partially fused aortic valve leaflets, is more commonly associated with a mobile bicuspid aortic valve than an immobile calcified aortic valve. The intensity of this sound does not vary with respiration, which helps distinguish it from the ejection click produced by a stenotic pulmonary valve, which will diminish slightly in intensity during inspiration.[33]
An easily heardsystolic, crescendo-decrescendo (i.e., 'ejection')murmur is heard loudest at the upper right sternal border, at the2nd right intercostal space,[24] and radiates to thecarotid arteries bilaterally.[4][12] The murmur increases with squatting and decreases with standing and isometric muscular contraction such as theValsalva maneuver, which helps distinguish it fromhypertrophic obstructive cardiomyopathy (HOCM). The murmur is louder during expiration but is also easily heard during inspiration. The more severe the degree of the stenosis, the later the peak occurs in the crescendo-decrescendo of the murmur.[34]
The second heart sound (A2) tends to become decreased and softer as the aortic stenosis becomes more severe.[24] This is a result of the increasing calcification of the valve, preventing it from "snapping" shut and producing a sharp, loud sound. Due to increases inleft ventricular pressure from the stenotic aortic valve, over time, the ventricle may hypertrophy, resulting in diastolic dysfunction. As a result, there may be afourth heart sound due to the stiff ventricle.[12] With continued increases in ventricular pressure, dilatation of the ventricle will occur, and a third heart sound may be manifest.[35]
Finally, aortic stenosis often co-exists with some degree ofaortic insufficiency (aortic regurgitation). Hence, the physical exam in aortic stenosis may also reveal signs of the latter, for example, an early diastolic decrescendo murmur. Indeed, when both valve abnormalities are present, the expected findings of either may be modified or may not even be present. Rather, new signs that reflect the presence of simultaneous aortic stenosis and insufficiency, e.g.,pulsus bisferiens, emerge.[citation needed]
According to ameta-analysis, the most useful findings for ruling in aortic stenosis in the clinical setting were slow rate of rise of the carotid pulse (positivelikelihood ratio ranged 2.8–130 across studies), mid to late peak intensity of the murmur (positive likelihood ratio, 8.0–101), and decreased intensity of the second heart sound (positive likelihood ratio, 3.1–50).[32]
Other peripheral signs include:[citation needed]
For asymptomatic severe aortic valve stenosis, the European guidelines[36] recommendB-type natriuretic peptide (BNP) measurements to aidrisk stratification and optimize the timing ofaortic valve replacement surgery.[37][38] In patients with non-severe asymptomatic aortic valve stenosis, increased age- and sex adjustedN-terminal pro-brain natriuretic peptide (NT-proBNP) levels alone and combined with a 50% or greater increase from baseline had been found associated with increased event rates of aortic valve stenosis related events (cardiovascular death, hospitalization withheart failure due to progression of aortic valve stenosis, oraortic valve replacement surgery).[39] In patients with non-severe asymptomatic aortic valve stenosis and no overtcoronary artery disease, the increasedtroponin T (above 14 pg/mL) was found associated with an increased 5-year event rate ofischemic cardiac events (myocardial infarction,percutaneous coronary intervention, orcoronary artery bypass surgery).[40]
Although aortic stenosis does not lead to anyspecific findings on theelectrocardiogram (ECG), it still often leads to a number of electrocardiographic abnormalities. ECG manifestations ofleft ventricular hypertrophy (LVH) are common in aortic stenosis[7][12] and arise as a result of the stenosis having placed a chronically high-pressure load on theleft ventricle (with LVH being the expected response to chronic pressure loads on the left ventricle no matter what the cause).[41]
As noted above, the calcification process that occurs in aortic stenosis can progress to extend beyond the aortic valve and into theelectrical conduction system of the heart. Evidence of this phenomenon may rarely include ECG patterns characteristic of certain types ofheart block, such asLeft bundle branch block.[7]
Cardiac chamber catheterization provides a definitive diagnosis, indicating severe stenosis in the valve area of <1.0 cm2 (normally about 3 cm2).[42] It can directly measure the pressure on both sides of the aortic valve. The pressure gradient may be used as a decision point for treatment. It is useful in symptomatic people before surgery.[12] The standard for diagnosis of aortic stenosis is non-invasive testing with echocardiography. Cardiac catheterization is reserved for cases in which there is a discrepancy between the clinical picture and non-invasive testing, due to risks inherent to crossing the aortic valve, such as stroke.[7]
| Severity of aortic stenosis[24] | ||
|---|---|---|
| Degree | Mean gradient (mmHg) | Aortic valve area (cm2) |
| Mild | <25 | >1.5 |
| Moderate | 25 - 40 | 1.0 - 1.5 |
| Severe | >40 | < 1.0 |
| Very severe | >70 | < 0.6 |
Echocardiogram (heart ultrasound) is the best non-invasive way to evaluate the aortic valve anatomy and function.[43]
The aortic valve area can becalculated non-invasively using echocardiographic flow velocities. Using the velocity of the blood through the valve, the pressure gradient across the valve can be calculated by the continuity equation or using the modifiedBernoulli's equation:
Gradient = 4(velocity)²mmHg
A normal aortic valve has a gradient of only a few mmHg. A decreased valvular area causes an increased pressure gradient, and these parameters are used to classify and grade the aortic stenosis as mild, moderate, or severe. The pressure gradient can be abnormally low in the presence ofmitral stenosis,heart failure, co-existentaortic regurgitation, and also ischaemic heart disease (disease related to the decreased blood supply and oxygen causing ischemia).[44]
Echocardiogram may also show left ventricular hypertrophy, a thickened and immobile aortic valve, and dilated aortic root.[12] However, it may appear deceptively normal in acute cases.[24]
Achest X-ray can also assist in the diagnosis and provide clues as to the severity of the disease, showing the degree of calcification of the valve, and in achronic condition, an enlarged left ventricle[12][24] and atrium.[12]
The use of CT calcium scoring is gaining popularity as a diagnostic tool to complement echo in the assessment of patients with aortic stenosis.[45][46] Aortic valve calcium scoring by multidetector computed tomography (CT-AVC) is used to quantify the degree of calcification of the aortic valve.[47] According to the 2021 ESC/EACTS Guidelines for the management of valvular heart disease the recommended thresholds indicating severe aortic stenosis are > 1200 AU in women and > 2000 AU in men.[48]
Treatment is generally not necessary in people without symptoms.[12] Inmoderate cases echocardiography is performed every 1–2 years to monitor the progression, possibly complemented with acardiac stress test.[24] In severe cases, echocardiography is performed every 3–6 months.[24] In both moderate and mild cases, the person should immediately make a revisit or be admitted forinpatient care if any new related symptoms appear.[24] There are no therapeutic options currently available to treat people with aortic valve stenosis; however, studies in 2014 indicated that the disease occurs as a result of active cellular processes, suggesting that targeting these processes may lead to viable therapeutic approaches.[49]
Observational studies demonstrated an association between lowered cholesterol withstatins and decreased progression, but arandomized clinical trial published in 2005 failed to find any effect on calcific aortic stenosis. The effect of statins on the progression of AS is unclear. A 2007 study found a slowing of aortic stenosis withrosuvastatin.[7][50] In 2013, it was reported that trials did not show any benefit in slowing AS progression,[7] but did demonstrate a decrease in ischemic cardiovascular events.[4]
In general, medical therapy has relatively poor efficacy in treating aortic stenosis.[12] However, it may be useful to manage commonly coexisting conditions that correlate with aortic stenosis:[51]
Aortic valve repair or aortic valve reconstruction describes the reconstruction of both form and function of the native and dysfunctional aortic valve. Most frequently, it is applied for the treatment of aortic regurgitation. It can also become necessary for the treatment of an aortic aneurysm, less frequently for congenital aortic stenosis.[54]
In adults, symptomatic severe aortic stenosis usually requiresaortic valve replacement (AVR).[4] While Surgical AVR has remained the most effective treatment for this disease process and is currently recommended for patients after the onset of symptoms, as of 2016[update] aortic valve replacement approaches included open-heart surgery, minimally invasive cardiac surgery (MICS), and minimally invasive catheter-based (percutaneous) aortic valve replacement.[55][56][57] However, surgical aortic valve replacement is well-studied, and generally has a good and well-established longer-term prognosis.[58]
A diseased aortic valve is most commonly replaced using a surgical procedure with either a mechanical or a tissue valve. The procedure is done either in an open-heart surgical procedure or, in a smaller but growing number of cases, a minimally invasive cardiac surgery (MICS) procedure.[citation needed] Minimally invasive approach via right minithoracotomy is most beneficial in the high risk patient such as the elderly, the obese, those with chronic obstructive pulmonary, chronic kidney disease and those requiring re-operative surgery.[59][60]
Globally, more than 250,000 people have receivedtranscatheter aortic valve intervention (TAVI). For people who are not candidates for surgical valve replacement and most patients who are older than 75, TAVI may be a suitable alternative.[55][56] Conduction abnormalities requiring permanent pacemaker (PPM) implantation remain a common finding after TAVI due to the proximity of the atrioventricular conduction system to the aortic root.[61]
For infants and children,balloon valvuloplasty, where a balloon is inflated to stretch the valve and allow greater flow, may also be effective. In adults, however, it is generally ineffective, as the valve tends to return to a stenosed state. The surgeon will make a small incision at the top of the person's leg and proceed to insert the balloon into the artery. The balloon is then advanced up to the valve and is inflated to stretch the valve open.[62]
Acute decompensated heart failure due to AS may be temporarily managed by anintra-aortic balloon pump while pending surgery.[63] In those with high blood pressurenitroprusside may be carefully used.[1]Phenylephrine may be used in those with very low blood pressure.[3]
If untreated, severe symptomatic aortic stenosis carries a poor prognosis, with a 2-year mortality rate of 50-60% and a 3-year survival rate of less than 30%.[64] Prognosis after aortic valve replacement for people younger than 65 is about five years less than that of the general population; for people older than 65, it is about the same.[58]
Approximately 2% of people over the age of 65, 3% of people over age 75,[4] and 4% of people over age 85 have aortic valve stenosis.[65] The prevalence is increasing with the aging population in North America and Europe.[66]
Median age at diagnosis of aortic stenosis is 77 years in men and 81 years in women.[67] Age-sex standardised incidence rates of aortic stenosis range from 52 (severe aortic stenosis) to 98 per 100 000 person-years in recent US and EU cohorts,[68][67]and is about 30% higher in men compared to women.[67]
Risk factors known to influence disease progression of AS include factors similar to those ofcoronary artery disease such as hypertension, advanced age, being male,hyperlipidemia,diabetes mellitus, cigarette smoking,metabolic syndrome, andend-stage kidney disease.[4][7][25]
Aortic stenosis was first described by French physician Lazare Rivière in 1663.[6]
People onbisphosphonates were found in a 2010 study to have less progression of aortic stenosis, and some regressed.[69][70] This finding led to multiple trials, ongoing as of 2012[update]. Subsequent research failed to confirm the initial positive result.[71]
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