Aortic Stenosis

Pratap Sagar Tiwari

Aortic Valve: Aortic Stenosis

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Aortic stenosis

• Aortic stenosis (AS) is narrowing of the aorticvalve resulting in obstruction of blood flowfrom the left ventricle to the ascending aortaduring systole.

EtiologyInfants, children, adolescents

Congenital aortic stenosisCongenital subvalvular aortic stenosisCongenital supravalvular aortic stenosis

Young adults to middle-aged

Calcification and fibrosis of congenitally bicuspid AVRheumatic aortic stenosis

Middle-aged to elderly

Senile degenerative aortic stenosisCalcification of bicuspid valveRheumatic aortic stenosis

William Syndrome

boyerpd1bio.wikispaces.com

↑ intraventricular pressure to maintain CO

Pathophysiology: AS

Angina , Syncope, Dyspnea

Valve

obstruction

Impaired passive fillingLVH ↓ Compliance↑preload dependance on

atrial contraction

↑LVEDP Subendocardial ischemia (↓ myocardial perfusion pressure)

Progressive valvular obstruction & increrasing wall stress

↑ Filling pressure , ventricular dilatation, contractile

dysfunction, ischemia, arrythmia

Ventricular wall hypertrophy (to reduce wall stress)

Symptoms

• The classic symptoms due to AS are heart failure(HF), syncope, and angina. However, these“classic” symptoms reflect end-stage disease.

• Now, with earlier diagnosis by echocardiographyand prospective followup of patients, the mostcommon presenting symptoms are:

1. Dyspnea on exertion or decreased exercise tolerance

2. Exertional dizziness3. Exertional angina

Dyspnea and decreased exercise tolerance

• The MC symptom of AS is dyspnea, usually with exertion.• 2 factors can contribute: diastolic dysfunction, with an ↑ in

LV filling pressures with exercise, and an inability of LV to ↑the CO during exercise because the stiff AV obstructs flow.

• Systolic LVdysfunction is rare and overt HF is a late, end-stage finding, usually in who havent received regularmedical care. Once overt HF occurs, the patient maycomplain of SOB, easy fatigability, debilitation, and otherS/S of a low CO state.

• AF, which is uncommon in isolated AS, often accompaniesHF.

Inspection: Carotid pulse

• The quality of the arterial pulse reflects the obstructionto blood flow into the peripheral arterial circulation.

• The arterial pulse :as "parvus and tardus", ie, it is smallor weak and rises slowly.

• Best appreciated in the carotid artery where the pulseis reduced in amplitude and delayed in occurrence.

• The delay can be appreciated by simultaneouspalpation of the apex (PMI) and the carotid artery.

• There may be :an associated carotid artery thrill orcoarse vibration ("shuddering") due to the markedturbulence of blood flow across the stenotic valve.

Palpation of Precordium

• The cardiac impulse at the apex is sustainedand is initially normal in location. (However, itbecomes displaced late in the course of ASwhen left ventricular failure occurs. )

• A systolic thrill :at the base of the heart (2ndICS ), especially during full expiration with thepatient leaning forward.

Cardiac auscultation :Heart Sounds

• S2 :soft and single since A2(due to Avclosure), is delayed and tendsto occur simultaneously with P2(due to PV closure).

• S2 may become paradoxically split when the stenosis is severe andassociated with LV dysfunction .

• With increasingly severe, fixed AS, the A2 closing sound maydisappear.

• The presence of a normal split S2 is the most reliable finding toexclude severe AS in adults.

• The S1 is usually N. However, an aortic ejection click, which is morecommonly heard with a congenital bicuspid valve, may be heardafter S1 (when the leaflets are stiff, but still somewhat compliantand mobile) .

• Vigorous LA contraction can lead to a S4.

AS: MURMUR

• The hallmark finding is a crescendo-decrescendoejection murmur, heard best with the diaphragm ofthe stethoscope at the right upper sternal border whena patient is sitting upright leaning forward.

• The murmur typically radiates to one or both carotidarteries and has a harsh or grating quality.

• The intensity of the systolic murmur does notcorrespond to the severity of AS; rather, the timing ofthe peak and the duration of the murmur correspondsto the severity of AS. The more severe the stenosis, thelonger the duration of the murmur and the more likelyit peaks at late systole.

• In elderly persons with calcific AS, however, the murmur may be more prominent at the apex, because of radiation of its high-frequency components (Gallavardinphenomenon). This may lead to its misinterpretation as a murmur of MR.

• The murmur is soft when stenosis is less severe, growslouder as stenosis progresses, and becomes longer andpeaks in volume later in systole (ie, crescendo phasebecomes longer and decrescendo phase becomes shorter)as stenosis becomes more severe.

• As LV contractility decreases in critical AS, the murmurbecomes softer and shorter. The intensity of the murmurmay therefore be misleading in these circumstances.

• The murmur of AS typically increases with maneuversthat increase LV volume and contractility (eg, leg-raising, squatting, Valsalva release,) and decreases withmaneuvers that decrease LV volume (Valsalvamaneuver) or increase afterload (isometric handgrip).

• These dynamic maneuvers have the opposite effect onthe murmur of hypertrophic cardiomyopathy, whichcan otherwise resemble that of AS.

• The murmur of MR due to prolapse of the posteriorleaflet may also mimic AS.

other

• A high-pitched, diastolic blowing murmur may bepresent if the patient has associated aorticregurgitation.

• Rarely, right ventricular failure with systemic venouscongestion, hepatomegaly, and edema precede LVfailure. This is probably due to the bulging of theinterventricular septum into the right ventricle, withimpedance in filling, elevated jugular venous pressure,and a prominent a wave (Bernheim effect).

•

Management

• Patients with symptomatic severe AS should haveprompt AV replacement.

• Old age is not a contraindication to valvereplacement .

• Aortic balloon valvuloplasty is useful incongenital aortic stenosis but is of no value inolder patients with calcific aortic stenosis.

• Anticoagulants are only required in patients whohave Afib or those who have had a valvereplacement with a mechanical prosthesis.

End of slides

References:

• Medscape

• Uptodate 20.3

• Harrison’s Internal medicine

• Davidson’s

• Merck’s mannual