= ascending aorta; lv = left ventricle; ecg = electrocardiogram.) palpation aortic stenosis is most often diagnosed when it is asymptomatic 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. 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 as pulsus parvus et tardus. there may also be a noticeable delay between the first heart sound (on auscultation) and the corresponding pulse in the carotid 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). auscultation the first heart sound may be followed by a sharp ejection sound ("ejection click") best heard at the lower left sternal border and the apex, and, thus, appear 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. an easily heard systolic, crescendo-decrescendo (i.e., 'ejection') murmur is heard loudest at the upper right sternal border, at the 2nd right intercostal space, and radiates to the carotid arteries bilaterally. the murmur increases with squatting and decreases with standing and isometric muscular contraction such as the valsalva maneuver, which helps distinguish it from hypertrophic 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. the second heart sound (a2) tends to become decreased and softer as the aortic stenosis becomes more severe. 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 in left ventricular pressure from the stenotic aortic valve, over time the ventricle may hypertrophy, resulting in diastolic dysfunction. as a result, there may be a fourth heart sound due to the stiff ventricle. with continued increases in ventricular pressure, dilatation of the ventricle will occur, and a third heart sound may be manifest. finally, aortic stenosis often co-exists with some degree of aortic 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. according to a meta-analysis, the most useful findings for ruling in aortic stenosis in the clinical setting were slow rate of rise of the carotid pulse (positive likelihood 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). other peripheral signs include: sustained, heaving apex beat, which is not displaced unless systolic dysfunction of the left ventricle has developed a precordial thrill narrowed pulse pressure electrocardiogram although aortic stenosis does not lead to any specific findings on the electrocardiogram (ecg), it still often leads to a number of electrocardiographic abnormalities. ecg manifestations of left ventricular hypertrophy (lvh) are common in aortic stenosis and arise as a result of the stenosis having placed a chronically high-pressure load on the left ventricle (with lvh being the expected response to chronic pressure loads on the left ventricle no matter what the cause). as noted above, the calcification process that occurs in aortic stenosis can progress to extend beyond the aortic valve and into the electrical conduction system of the heart. evidence of this phenomenon may rarely include ecg patterns characteristic of certain types of heart block such as left bundle branch block. heart catheterization cardiac chamber catheterization provides a definitive diagnosis, indicating severe stenosis in valve area of <1.0 cm2 (normally about 3 cm2). 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. 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. echocardiogram severity of aortic stenosis degreemean gradient (mmhg)aortic valve area (cm2) mild<25>1.5 moderate25 - 401.0 - 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. the aortic valve area can be calculated 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 modified bernoulli's equation: gradient = 4(velocity)² mmhg a normal aortic valve has a gradient of only a few mmhg. a decreased valvular area causes 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 of mitral stenosis, heart failure, co-existent aortic regurgitation and also ischaemic heart disease (disease related to the decreased blood supply and oxygen causing ischemia). echocardiogram may also show left ventricular hypertrophy, thickened and immobile aortic valve, and dilated aortic root. however, it may appear deceptively normal in acute cases. chest x-ray a chest 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 a chronic condition, an enlarged left ventricle and atrium. computer tomography the use of ct calcium scoring is gaining spread as a diagnostic tool to complement echo in the assessment of patients with aortic stenosis. aortic valve calcium scoring by multidetector computed tomography (ct-avc) is used to quantify the degree of calcification of the aortic valve. 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. management treatment is generally not necessary in people without symptoms. in moderate cases echocardiography is performed every 1–2 years to monitor the progression, possibly complemented with a cardiac stress test. in severe cases, echocardiography is performed every 3–6 months. in both moderate and mild cases, the person should immediately make a revisit or be admitted for inpatient care if any new related symptoms appear. 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. medication observational studies demonstrated an association between lowered cholesterol with statins and decreased progression, but a randomized 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 with rosuvastatin. in 2013 it was reported that trials did not show any benefit in slowing as progression, but did demonstrate a decrease in ischemic cardiovascular events. in general, medical therapy has relatively poor efficacy in treating aortic stenosis. however, it may be useful to manage commonly coexisting conditions that correlate with aortic stenosis: any angina is generally treated with beta-blockers and/or calcium blockers. nitrates are contraindicated due to their potential to cause profound hypotension in aortic stenosis. any hypertension is treated aggressively, but caution must be taken in administering beta-blockers. any heart failure is generally treated with digoxin and diuretics, and, if not contraindicated, cautious administration of ace inhibitors. aortic valve repair main article: aortic valve repair aortic valve repair or aortic valve reconstruction describes the reconstruction of both form and function of the native and dysfunctioning 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. aortic valve replacement main article: aortic valve replacement in adults, symptomatic severe aortic stenosis usually requires aortic valve replacement (avr). 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 aortic valve replacement approaches included open-heart surgery, minimally invasive cardiac surgery (mics), and minimally invasive catheter-based (percutaneous) aortic valve replacement. however, surgical aortic valve replacement is well-studied, and generally has a good and well-established longer-term prognosis. 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. 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. transcatheter aortic valve replacement globally more than 250,000 people have received transcatheter 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. conduction abnormalities requiring permanent pacemaker (ppm) implantation remain a common finding after tavi due to the close proximity of the atrioventricular conduction system to the aortic root. balloon valvuloplasty 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. heart failure acute decompensated heart failure due to as may be temporarily managed by an intra-aortic balloon pump while pending surgery. in those with high blood pressure nitroprusside may be carefully used. phenylephrine may be used in those with very low blood pressure. prognosis 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%. 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. epidemiology approximately 2% of people over the age of 65, 3% of people over age 75, and 4% percent of people over age 85 have aortic valve stenosis. the prevalence is increasing with the aging population in north america and europe. risk factors known to influence disease progression of as include factors similar to those of coronary artery disease such as hypertension, advanced age, being male, hyperlipidemia, diabetes mellitus, cigarette smoking, metabolic syndrome, and end-stage kidney disease. history aortic stenosis was first described by french physician lazare rivière in 1663. research people on bisphosphonates were found in a 2010 study to have less progression of aortic stenosis, and some regressed. this finding led to multiple trials, ongoing as of 2012. subsequent research failed to confirm the initial positive result.