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Aortic Stenosis

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About

Untreated symptomatic aortic stenosis has a prognosis of 2-3 years
Increased LV outflow obstruction leading to LV failure
Commonest valvular lesion most common in men
Seen in approximately 3% of those over 75

Anatomy

The aortic valve has three leaflets, each having a cusp or cup-like configuration.
Left coronary cusp (L), the right coronary cusp (R) and the posterior non-coronary cusp (N).
Above the aortic valves anatomic dilations known as the sinus of Valsalva.

Pathology

Bicuspid valve risk for stenosis
Aortic stenosis +/- Aortic regurgitation
Supravalvular stenosis

Aetiology

LV generates an intraventricular pressure of systolic blood pressure + pressure gradient drops across valve
Can lead to LV pressures > 200 mmHg with Myocardial ischaemia
Diastolic dysfunction too with LV hypertrophy and low aortic root pressure
This increases wall stress, work and impairs coronary flow.
Causes LVH and ultimately LV fails. Needs surveillance
High LVEDP (PAOP) to fill non-compliant ventricle
Sinus rhythm a high priority, normal heart rate
Vasodilation may severely impair coronary and cerebral perfusion and BP

Causes

Commoner Causes	Details
Calcific Aortic Valve Disease (CAVD)	The most common cause in older adults. Progressive calcification of the aortic valve leaflets, leading to restricted valve opening. Age-related and similar to atherosclerosis, involving inflammation and lipid deposition in the valve.
Bicuspid Aortic Valve (BAV)	A congenital condition. Has two leaflets instead of the normal three. Early and more rapid calcification, leading to AS in the 50s or 60s.
Rheumatic Heart Disease	Causes AS due to post-inflammatory scarring and fusion of the AV leaflets. This condition often occurs in conjunction with mitral valve disease. Developing countries where rheumatic fever is prevalent.
Rare Causes	Details
Radiation-Induced Aortic Stenosis	Radiation therapy to the chest post Hodgkin's lymphoma or breast cancer, can cause fibrosis and calcification of the aortic valve years after treatment. This leads to progressive aortic stenosis.
William's syndrome	Supravalvular stenosis. Hypercalcaemia and elfin face and reduced IQ.
Infective Endocarditis	Infective endocarditis if the infection leads to significant damage to the valve leaflets, resulting in scarring and calcification. Often leads to mixed AR/AS.
Connective Tissue Disorders	Marfan syndrome or Ehlers-Danlos syndrome can affect the aortic root and valve structure, leading to AV dysfunction, including stenosis.
Hyperlipoproteinemia	Hyperlipoproteinemia, elevated lipoprotein(a) levels, can accelerate calcification of the aortic valve. This condition is similar in pathogenesis to atherosclerosis and contributes to early-onset aortic stenosis.

Measuring Severity

Severity by valve area (<1 cm² severe) or pressure gradient
Aortic jet velocity and rate of change in jet velocity
Degree of calcification
Functional status, older age
Coronary artery disease, Diabetes mellitus
Signs of LVF, Soft single S2, Paradoxically Split S2
Precordial thrill, Slow rising pulse, narrow pulse pressure
Late peaking of long murmur
valve gradient < 0.5 cm² on echocardiogram
Gradient > 60 mmHg on catheter

Clinical: Ask about Chest pain/Syncope/Dyspnoea

Asymptomatic, Fatigue, Exertional Dyspnoea
Pre syncope and syncope often exercise-induced
Anginal Chest pain - even with normal coronary arteries
Late disease - cardiac failure and LV dilatation and shifted apex beat
Slow rising plateau pulse
Aortic thrill and Ejection systolic murmur? to carotids
Forceful heaving sustained apex beat with a palpable S4
Displacement of the apex is not till late when LV dilates
Soft, split and possibly reversed S2
Left ventricular failure is usually a late sign
The A2 gets fainter as disease progresses and will disappear
Ejection clicks if valve pliable e.g. bicuspid valve

Complications

LV failure, Arrhythmias
Sudden cardiac death, Stokes Adams attacks

Investigations

Bloods: FBC, U&E, LFT, ↑ CRP - think Endocarditis
ECG: LVH + strain pattern
CXR: LV enlargement, Post stenotic dilatation
Echocardiogram: Doppler shows gradient drop across valve. Severe is mean gradient > 50 mmHg. Measure valve area < 1 cm² very severe < 0.5 cm²
Cardiac catheterisation - pressure drop across valve can be measured if the valve can actually be safely crossed. Angiography may be considered and valve + CABG may be done in selected patients
Aortic valve orifice area index is becoming a more commonly used measurement which is calculated from aortic valve orifice area divided by body surface area.

Differential

Aortic sclerosis: Aortic Stenosis more likely if plateau pulse, S4, late peaking of murmur, symptoms e.g. chest pain, heart failure, a loud murmur and thrill
Hypertrophic cardiomyopathy

Management

Treatment Option	Details
Watchful Waiting	Indicated for patients with mild or asymptomatic aortic stenosis. Regular monitoring with echocardiography to assess progression of stenosis. Patients should be educated on recognizing symptoms like chest pain, shortness of breath, or syncope. Patients with mild disease are usually seen annually or sometimes every 2 years at the clinic.
Medical Management	Medical therapy can manage symptoms and associated conditions. Diuretics: e.g. Furosemide IV/PO to manage heart failure symptoms due to fluid overload. Beta-blockers: treat hypertension and reduce myocardial oxygen demand, although care is needed to avoid excessive bradycardia. Statins: may slow the progression of calcific aortic stenosis, but evidence is not conclusive. ACEI/vasodilators: avoided in moderate to severe disease as may cause profound hypotension as their vasodilator function
Surgical Aortic Valve Replacement (SAVR)	Indicated for patients with severe, symptomatic aortic stenosis, or asymptomatic patients with reduced left ventricular ejection fraction. Definitive treatment. When symptomatic and pressure gradient > 50 mmHg or if asymptomatic and gradient >> 50 mmHg and valve area < 0.7 cm². Surgical AVR involves open-heart surgery to replace the stenotic valve with a mechanical or bioprosthetic valve. Mechanical valves require lifelong anticoagulation, while bioprosthetic valves generally do not but may have a shorter lifespan. SAVR is a procedure carried out with good results even in the over 80s.
Transcatheter Aortic Valve Replacement (TAVR)	A less invasive option for patients who are high-risk or unsuitable candidates for surgery. TAVR is performed via catheterization, inserting a new valve within the stenotic valve without open-heart surgery. Increasingly used in lower-risk patients as well, with comparable outcomes to SAVR in selected populations. For older frail patients with the severe symptomatic disease who are not suitable for AVR and have a life expectancy greater than one year and who will gain improvements in quality of life. Can be done under LA or GA. The bioprosthetic valve is delivered via a femoral or transapical approach. Trans oesophageal Echocardiography and fluoroscopy is used to guide placement. It is done on a beating heart and no bypass is needed. Can be done under local or general anaesthesia. Early discharge at 72 hours is possible. TAVI can result in good quality of life. Survival is 50% at 18 months in those with untreated aortic stenosis induced LVF. May be considered on those in whom conventional valve replacement is not possible.
Balloon Aortic Valvuloplasty (BAV)	A palliative procedure that temporarily relieves aortic stenosis by dilating the valve with a balloon catheter. Often used as a bridge to surgery or TAVR in critically ill patients or those requiring urgent non-cardiac surgery. Less effective long-term due to the high rate of restenosis. It is is useful in congenital aortic stenosis but not in older patients with frailty where valves are heavily calcified. TAVI is now preferred.
Management of Comorbidities	Control of hypertension, diabetes, and hyperlipidemia is essential to reduce overall cardiovascular risk. Heart failure management includes cautious use of diuretics and afterload reduction. Patients should be managed according to guidelines for atrial fibrillation, coronary artery disease, and other relevant conditions.
Lifestyle Modifications	Patients should engage in regular, moderate exercise if asymptomatic, but avoid strenuous activities if symptomatic. Dietary modifications, including reduced salt intake, can help manage blood pressure and fluid retention. Smoking cessation and weight management are crucial for overall cardiovascular health.

References

2017 ESC/EACTS Guidelines for the management of valvular heart disease

PLEASE NOTE LEGAL ADVICE: The contents are under continuing development and improvements and may contain errors of omission or fact. Feedback vital and always welcome at drokane at gmail.com. This is not to be used for the assessment, diagnosis or management of patients. It should not be regarded as medical advice. It is only for educational purposes. Please adhere to your local protocols. If you are unwell please seek healthcare advice from your doctor. This does not replace senior or specialist advice. If you do not accept this then please do not use the website. If you need medical advice, please consult a doctor or other appropriate medical professional. If you are a medical professional and you need advice then speak to your senior or colleagues.

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