Aortic Stenosis

Aortic Stenosis

 

Etiology

 

  • Overall, most common cause Calcification

 

(1) Calcification (normal ageing)

 

  • Most common cause in older patients > 65 years

 

(2) Bicuspid aortic valve

 

  • Most common cause in younger patients < 65 years

  • Normal aortic valve is tricuspid (the only bicuspid valve is mitral valve); bicuspid aortic valve may be stenotic due to cusp fusion.

 

(3) William’s syndrome (supravalvular stenosis)

 

  • A congenital fibrous diaphragm is present above the aortic valve.

 

C:\Users\ayyan\Desktop\williams.jpg

 

(4) HOCM (subvalvular stenosis)

 

(5) Rheumatic heart disease

 

  • RHD may result in aortic valve stenosis due to cusp fusion.

 

 

Assessing the severity

 

Severity of AS is assessed by:

 

  • Valve area

  • Pressure gradient across the valve

 

  • Normal valve area = 3 – 4 cm2{cm} ^ {2}

  • Normal valve gradient < 5 mmHg

 

 

Severity of aortic stenosis

Severity valve area (cm2{cm} ^ {2})

Mean gradient (mmHg)

Mild

1.5 - 3

< 25

Moderate

1.0 – 1.5

25 - 50

Severe

< 1.0

> 50

Critical

< 0.7

> 80

 

 

Symptoms

 

The classic triad of AS is:

 

(1) Angina (exertional)

Angina occurs due to 3 reasons:

 

  • Oxygen demand due to LVH

  • Coronary perfusion due to stenosis and C.O

  • In 50% of AS patients above the age of 35 years, angina occurs due to coexisting CAD.

 

(2) SOB (exertional)

 

SOB/orthopnea/PND occurs due to both:

 

  • Systolic failure (dilated ventricles due to high pressure - ​​ dilated cardiomyopathy)

  • Diastolic failure (LVH - Hypertrophic cardiomyopathy)

 

(C) Syncope (on exertion)

 

 

Examination

 

GENERAL PHYSICAL EXAMINATION

 

(1) CAROTID PULSE

 

  • “Low volume” and “slowly rising pulse” called slow rising pulse.

 

C:\Users\ayyan\Desktop\pulse.jpg

(2) PULSE PRESSURE

  • Narrow (because systolic pressure decreases due to C.O

 

PulsePressure=SystolicDiastolic↓ Pulse Pressure= ↓ Systolic -Diastolic

 

C:\Users\ayyan\Desktop\Untitled.jpg

 

  • Vs. aortic regurgitation, in which pulse pressure becomes wide (due to increased cardiac out resulting in increased systolic pressure)

 

(3) JVP

 

Prominent “a” wave – This is due to reduced compliance of right ventricle which is due to:

 

  • Hypertrophy of ventricular septum

  • Pulmonary hypertension

 

“a” WAVE

 

PRODUCED BY

 

a” wave is produced by “atrial contraction” (late ventricular diastole).

 

C:\Users\ayyan\Desktop\JVP.jpg

 

PROMINENT “a” WAVE

 

“a” wave will be prominent whenever atrial pressure increases:

 

  • Pulmonary hypertension ​​ (any disease causing left sided heart failure)

  • Pulmonary stenosis

  • HOCM

  • Tricuspid stenosis

 

All these conditions causes: RV pressure RA pressure Prominent “a” wave

ABSENT “a” WAVE

 

  • Atrial fibrillation

 

 

 

 

 ​​​​ CVS examination

 

PALPATION

 

(1) APEX BEAT

  • Site: Not displaced (The concentric hypertrophy, in contrast to, dilatation, does not produce cardiomegaly)

  • Character: Heaving (forceful – Due to LVH)

 

CONCENTRIC LVH (hypertrophic cardiomyopathy)

 

  • Concentric hypertrophy is a hypertrophic growth of a hollow organ without overall enlargement, in which the walls of the organ are thickened and its capacity or volume is diminished.

  • LV mass” as well as “wall thickness” increases; but wall thickness increases on the inside of ventricular wall; so:

.

 

  • Ventricular cavity size decreases, and

  • Cardiomegaly does not occur (apex beat not displaced)

 

  • The center of the circle remains in the center.

  • It is caused by volume overload (aortic regurgitation, mitral regurgitation, septal defects, pregnancy)

 

C:\Users\ayyan\Desktop\hypertrophy.jpg

 

 

Eccentric LVH (dilated cardiomyopathy)

 

  • LV mass” increases but “wall thickness” remains normal or decreased.

.

 

  • But ventricular cavity size increases, so

  • Cardiomegaly occurs (apex beat displaced)

 

  • The center of circle is in the periphery of the circle.

  • It is caused by pressure overload (aortic stenosis, HOCM, HTN)

 

 

 

Eccentric hypertrophy

Concentric hypertrophy

LV mass

Increased

Increased

LV wall thickness

Normal or decreased

Increased

 

(but on the inside, so no cardiomegaly – Apex beat not displaced)

Cavity

Dilated

 

(Results in cardiomegaly – Displaced apex beat))

Normal

Type of heart failure

Systolic

 

(Dilated cardiomyopathy)

Diastolic

 

(Hypertrophic cardiomyopathy)

 

Added sounds

  • S3 (Increased early diastolic filling into compliant dilated ventricle)

 

  • S4 (Hypertrophy limits diastolic filling)

 

S4

Causes

Increase in left ventricular volume ​​ (and pressure):

 

  • Valvular regurgitations (Aortic regurgitation + Mitral regurgitation

  • Septal defects

  • Pregnancy

Chronic pressure overload

 

  • Aortic stenosis

  • HOCM

  • HTN

 

(2) SYSTOLIC THRILL

  • At aortic area

 

AUSCULTATION

 

HEART SOUNDS

 

(1) S2:

  • Soft”:

 

  • REASON: Calcified aortic valve is immobile A2 is not audible; only P2 is audible Soft S2

  • SEVERE AS: When S2 is not audible, it can be concluded that AS is severe.

  • Reverse splitting of S2:

 

  • REASON: Delayed closure of aortic valve due to AS → P2 occurs earlier than A2 → Reverse splitting of S2

(2) S4:

 

  • Due to LVH

 

MURMUR (EJECTION – SYSTOLIC)

 

Radiation:

 

  • Carotid artery: The ejection systolic murmur of HOCM does not radiate to neck which helps in differentiating it from murmur of AS.

  • Apex: Murmur of MR at apex is “pansystolic” while that of AS is ejection-systolic.

 

C:\Users\ayyan\Desktop\e964ee6d8bd13247e6118bfaa0e7ea79.jpg

 

Maneuvers:

 

  • Valsalva, standing, hand grip: Murmur decreases due to transvalvular flow

  • Squatting, leg raise: Murmur increases due to transvalvular flow

 

Duration:

  • Longer the murmur, severe is aortic stenosis.

 

Intensity:

  • Intensity of murmur typically increases as the disease progresses.

  • However, in very severe aortic stenosis, cardiac output decreases; as a result, the murmur becomes “softer” or “disappears”. Therefore, intensity of murmur is not a good indicator of disease severity.

 

 

Investigations

 

TTE TEE Cardiac catheterization

 

(1) CXR:

  • Normal (concentric hypertrophy – no cardiomegaly)

 

(2) ECG

  • LVH

 

(3) Echo:

 

​​ Echo can determine:

 

  • Valve area

  • Pressure gradient

 

(4) Cardiac catherization

 

Cardiac catherization is indicated in three conditions:

 

  • Measure gradient: Rarely, cardiac catherization is indicated to measure gradient if echocardiography is unable to determine whether severe aortic stenosis is present or not.

 

  • Angina: Cardiac catherization is indicated when it is suspected that the angina of aortic stenosis may be due to coexisting CAD (50% of aortic stenosis patients older than 35 years of age have CAD).

  • AVR: Angiography should be done before AVR, so that CABG, if indicated, can be performed during the procedure of valve replacement.

 

Treatment

 

(1) ASYMPTOMATIC

 

  • Mild to moderate AS: If the patient is asymptomatic, and AS is not severe, just observe the patient is the general rule.

  • Severe AS: AVR is indicated

 

​​ (2) SYMPTOMATIC

 

  • Medical treatment is not effective.

  • Development of any of the three symptoms is indication for AVR.

 

(A) MEDICAL TREATMENT

  • BETA BLOCKERS: Can be used for angina (but may cause hypotension)

  • ACE INHIBITORS, DIGOXIN, NITRATES: Just like HOCM, these drugs are relatively contraindicated.

 

 

 

Drug

Indication

ACE inhibitors

Symptomatic systolic failure

Digoxin

Decreased EF

Nitrates

Angina

 

 

 

 

 

(B) Surgical treatment

 

(i) AVR

C:\Users\ayyan\Desktop\hqdefault.jpg

INDICATIONS:

 

  • Symptomatic patients (any of the three symptoms)

  • Asymptomatic but severe AS (i.e; valvular gradient > 50 mmHg or valve area < 0.7)

  • Patients undergoing CABG or any other heart surgery

 

 

 

 

C:\Users\ayyan\Desktop\Image_201510071501_10068.jpg

 

(II) BALOON VALVULOPLASTY

 

Definition: It is widening of stenotic aortic valve using a balloon catheter inside the valve.

 

INDICATION: Patients with “critical” aortic stenosis who are not fit for AVR.

 

NOTE: Baloon valvuloplasty is not routinely done because “calcified” aortic stenosis does not respond very well to balloon valvuloplasty.

 

 

TAGS: aortic stenosis murmur radiation causes signs symptoms listen murmur location aortic stenosis treatment

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