B.32 Aortic Valve Stenosis Flashcards
B.32 Aortic Valve Stenosis
define
Systolic Murmur
Aortic valve stenosis (AS) is a valvular heart disease characterized by narrowing of the aortic valve.
As a result, the outflow of blood from the left ventricle into the aorta is obstructed.
This leads to chronic and progressive excess load on the left ventricle and potentially left ventricular failure.
B.32 Aortic Valve Stenosis
Epidemiology
Most common valvular heart disease in industrialized countries
Frequently associated with aortic regurgitation
Prevalence
Increases with age
May reach up to 12.4% among individuals ≥ 75 years
B.32 Aortic Valve Stenosis
Etiology
Aortic valve sclerosis: calcification and fibrosis of aortic valve leaflets
Most common cause of aortic stenosis
Occurs at an increasing rate as patients age (prevalence is 35% in those aged 75–85 years) [3]
Similar pathophysiology to atherosclerosis (see risk factors for atherosclerosis)
Bicuspid aortic valve (BAV): fusion of two of the three aortic-valve leaflets in utero
Most common congenital heart valve malformation , predominantly affects males (3:1)
Predisposes the valve to dystrophic calcification and degeneration
Patients present with symptoms of aortic stenosis earlier than in regular aortic valve calcification.
Congenital aortic stenosis is rare and usually features a unicuspid or bicuspid valve.
Rheumatic fever
Rare cause of AS in high-income countries due to consistent use of antibiotics for the treatment of streptococcal pharyngitis
Still remains a significant cause of AS in lower-income countries, where antibiotics may be less readily available
Stenosis is caused by commissural fusion.
B.32 Aortic Valve Stenosis
Pathophys
Narrowed opening area of the aortic valve during systole → obstruction of blood flow from left ventricle (LV) → increased LV pressure → left ventricular concentric hypertrophy, which leads to:
- Increased LV oxygen demand
- Impaired ventricular filling during diastole → left heart failure
- Reduced coronary flow reserve
Initially, cardiac output (CO) can be maintained
Later, the decreased distensibility of the left ventricle reduces cardiac output and may then cause backflow into the pulmonary veins and capillaries → higher afterload (pulmonic pressure) on the right heart → right heart failure
B.32 Aortic Valve Stenosis
signs and symptoms
Dyspnea (typically exertional)
Angina pectoris
Dizziness and syncope
Additional signs specific to infants: wheezing and difficulty feeding
B.32 Aortic Valve Stenosis
physical exam
Small blood pressure amplitude, decreased pulse pressure
Weak and delayed distal pulse (pulsus parvus et tardus)
Palpable systolic thrill over the bifurcation of the carotids and the aorta
B.32 Aortic Valve Stenosis
Auscultation
Harsh crescendo-decrescendo (diamond-shaped), late systolic ejection murmur that radiates bilaterally to the carotids
Best heard in the 2nd right intercostal space - Results from the blood rushing through the narrowed opening of the aortic valve
Handgrip decreases the intensity of the murmur. - Due to increased afterload
Valsalva and standing from squatting decreases or does not change the intensity of the murmur (in contrast to hypertrophic cardiomyopathy).
Soft S2- S2 is the sound of the aortic and pulmonary valves closing. A soft S2 results from a delay in the aortic component (A2) and softer closing of the aortic valve due to reduced mobility.
S4 is best heard at the apex. - Results from the abrupt stop of the valve leaflets upon opening
Early systolic ejection click
B.32 Aortic Valve Stenosis
Echocardiography
Indication: assessment of aortic valve structure, function, and stenosis severity, left ventricle and other heart valves
TTE: recommended primary test and noninvasive gold standard used to confirm diagnosis and determine AS severity
TEE: second-line modality for confirmation of TTE findings or operative planning
Supportive findings
Calcification and narrowing of the aortic valve
Increased mean aortic pressure gradient and transvalvular velocity
Signs of cardiac remodeling, e.g., concentric hypertrophy
B.32 Aortic Valve Stenosis
Lab Findings
usually nonspecific and therefore not routinely indicated; however, they can be useful for the evaluation of other possible etiologies.
BNP/NT-proBNP - Symptomatic patients usually have a higher concentration of BNP. Rise in BNP in asymptomatic patients may indicate impending onset of symptoms.
Troponin T/I - Some studies have shown elevated cardiac troponin in patients with aortic stenosis. Elevated cardiac troponin may even be a prognostic factor.
B.32 Aortic Valve Stenosis
ECG
ECG signs of LVH (e.g., positive Sokolow-Lyon index)
Nonspecific ST-segment and T-wave abnormalities
B.32 Aortic Valve Stenosis
CXR
Used to assess for pulmonary edema or other causes of dyspnea.
Visible calcifications within the aortic valve may indicate more severe disease.
Narrowing of retrocardiac space (lateral view)
Signs of cardiac remodeling and associated heart failure: x-ray signs of LVH, pulmonary congestion, poststenotic dilation of the aorta
B.32 Aortic Valve Stenosis
TX
Symptomatic and/or severe AS: Aortic valve replacement or repair is usually indicated. - The choice of intervention (i.e., open surgical vs. catheter-based) depends on the AHA classification, echocardiographic parameters, and surgical risk.
Asymptomatic or mild-to-moderate AS: usually treated conservatively; consider early aortic valve replacement in select patients
B.32 Aortic Valve Stenosis
Aortiv Valve Replacement and/or Repair (AVR) Indications
Indications
Symptomatic patients with severe, high-gradient AS (stage D AS)
Asymptomatic patients with severe AS and Significantly ↓ LVEF (stage C2 AS)
B.32 Aortic Valve Stenosis
AVR Procedure
Surgical AVR (SAVR) is recommended for patients with:
Age < 65 years
Life expectancy > 20 years
Low to moderate surgical risk
Transcatheter AVR (TAVR)
Recommended for patients with:
Age > 80 years
Life expectancy < 10 years
High or prohibitive surgical risk and predicted survival of > 12 months
Emergency TAVR may be considered in certain patient groups
Percutaneous balloon valvuloplasty
May be used in children, adolescents, and young adults
Limited role in older patients
B.32 Aortic Valve Stenosis
Transcatheter AVR (TAVR)
A minimally invasive, percutaneous procedure that utilizes an endovascular technique to replace the aortic valve.
A collapsible replacement valve is inserted via a catheter and placed over the native valve.
Once the replacement valve is expanded, it displaces the old valve and assumes its function.
PHARMA
vitamin k agonist and if old add anti-platelet e.g. ASA
B.32 Aortic Valve Stenosis
Complications
Cardiogenic shock
Acute heart failure (AHF)
Atrial fibrillation with RVR
B.32 Aortic Valve Stenosis
What is the classic triad of symptoms
Angina – due to ↑ demand + ↓ coronary perfusion
Syncope – especially with exertion (fixed CO)
Dyspnoea / heart failure – due to LV dysfunction
Once symptoms appear, prognosis worsens sharply
→ untreated severe AS: survival is 2–3 years after heart failure develops
B.32 Aortic Valve Stenosis
A loud murmur in AS means severe disease – true or false?
→ ❌ False – a softer murmur may indicate severe AS if LV fails to generate high pressure.
B.32 Aortic Valve Stenosis
The murmur of AS radiates to the axilla – true or false?
→ ❌ False – it radiates to the carotids.
B.32 Aortic Valve Stenosis
Patient with syncope and AS – do you order an exercise stress test?
→ ❌ Absolutely not – contraindicated in symptomatic AS.
B.32 Aortic Valve Stenosis
All patients with AS need antibiotics for dental procedures – true or false?
→ ❌ False – only if there’s prosthetic valve or prior infective endocarditis
