Aortic Valve diseases Flashcards
what is the aetiology of aortic stenosis?
Aortic valve sclerosis: calcification and fibrosis of aortic valve leaflets [2]
Most common cause of aortic stenosis
increasing rate as patients age; aged 75–85 years
Bicuspid aortic valve (BAV): fusion of two of the three aortic-valve leaflets in utero [2]
Predisposes the valve to dystrophic calcification and degeneration
Patients present with symptoms of aortic stenosis earlier than in regular aortic valve calcification.
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. [3]
what is the pathophysio of aortic stenosis?
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 (see “Compensation mechanisms” in “Congestive heart failure”)
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
what are the clinical features of aortic stenosis?
Aortic stenosis may remain asymptomatic for years, particularly with mild or moderate stenosis. Symptoms usually start to develop when the disease progresses to severe AS, and may present at rest or on exertion.
Signs and symptoms
Dyspnea (typically exertional)
Angina pectoris
Dizziness and syncope
Additional signs specific to infants: wheezing and difficulty feeding
Physical examination
Small blood pressure amplitude, decreased pulse pressure
Weak and delayed distal pulse (pulsus parvus et tardus) [2]
Palpable systolic thrill over the bifurcation of the carotids and the aorta [2]
See cardiovascular examination for further details.
Auscultation
Harsh crescendo-decrescendo (diamond-shaped), late systolic ejection murmur that radiates bilaterally to the carotids
Best heard in the 2nd right intercostal space
Handgrip decreases the intensity of the murmur.
Valsalva and standing from squatting decreases or does not change the intensity of the murmur (in contrast to hypertrophic cardiomyopathy).
See auscultation in valvular defects for comparison with other valvular heart diseases.
Soft S2
S4 is best heard at the apex.
Early systolic ejection click
To remember the three major symptoms of aortic valve stenosis, think: SAD (syncope, angina, dyspnea).
how do you diagnose aortic stenosis?
Echocardiography [8]
Indication: Assessment of aortic valve structure, function, and stenosis severity, left ventricle and other heart valves (see valvular heart diseases)
TTE: recommended primary test and noninvasive gold standard used to confirm diagnosis and determine AS severity [8]
TEE: second-line modality for confirmation of TTE findings or operative planning [9]
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
ECG
ECG signs of LVH (e.g., positive Sokolow-Lyon index)
Nonspecific ST-segment and T-wave abnormalities
Chest x-ray: Used to assess for pulmonary edema or other causes of dyspnea. [2]
Visible calcifications within the aortic valve may indicate more severe disease. [3]
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
Cardiac catheterization
Diagnostic hemodynamic cardiac catheterization: definitive diagnostic test to evaluate aortic valve area, cardiac output, and mean aortic pressure gradient
Consider in symptomatic patients with inconclusive noninvasive testing or discrepancy between symptoms and noninvasive testing. [13]
Findings: similar to echocardiographic findings
Coronary angiography
Indication: Preoperative cardiac risk stratification for patients with angina, reduced LVEF, signs of ischemia, or other CAD risk factors
Findings: signs of CAD (e.g., coronary stenosis)
what is the treatment for aortic stenosis?
Aortic valve stenosis is a progressive condition and definitive management requires valve replacement.
Urgency of valve repair/replacement depends on staging.
Symptomatic and/or severe AS: aortic valve replacement usually indicated
Asymptomatic or mild-moderate AS: management of medical comorbidities and monitoring echocardiography; some may benefit from early valve replacement [16]
Management of acute complications requires individualized and specialized care.
Medical management
Monitoring and prophylactic antibiotics [8]
Echocardiography
Regular follow-up imaging is indicated for asymptomatic patients
Prophylactic antibiotics
Rheumatic heart disease: should receive secondary prophylaxis (see “Prevention” in rheumatic fever for more details). [27]
Dental procedures: consider prophylaxis for infective endocarditis
Aortic valve replacement (AVR) and repair
Indications
Symptomatic patients with severe, high-gradient AS
Asymptomatic patients with severe AS and:
Significantly ↓ LVEF
Undergoing cardiac surgery for other indications
The presence of exertional symptoms (dyspnea on exertion, angina pectoris, syncope) is an indication for surgery.
Procedure
Surgical AVR
Recommended for patients with: [8]
Low to moderate surgical risk
Higher surgical risk AND severe multivessel coronary artery disease
Transcatheter AVR (TAVR)
Recommended for patients with high or prohibitive surgical risk and predicted survival of > 12 months [8][14]
Percutaneous balloon valvuloplasty
Indicated in children, adolescents, and young adults without AV calcification
what is the aetiology of aortic regurg?
Acute AR
Infective endocarditis
Aortic dissection (ascending aorta)
Chest trauma
Chronic AR
Congenital bicuspid valve: most common cause of AR in young adults and in developed countries
Rheumatic heart disease: most common cause of AR in developing countries
Distortion or dilation of the ascending aorta and aortic root
Connective tissue disorders (e.g., Marfan syndrome, Ehlers-Danlos syndrome)
Tertiary syphilis
Also see heart valve disease
what is the pathophysio of aortic regurg?
General
Regurgitation of blood from the aorta into the left ventricle (LV)
→ Increased systolic blood pressure and decreased diastolic pressure
→ Widened pulse pressure → water hammer pulse (see “Diagnostics” below)
Acute AR
Because LV cannot sufficiently dilate in response to regurgitant blood, LV end-diastolic pressure increases rapidly → pressure transmits backwards into pulmonary circulation → pulmonary edema and dyspnea
Decreased cardiac output if severe → cardiogenic shock and myocardial ischemia
Chronic AR
Initially, a compensatory increase in stroke volume can maintain adequate cardiac output despite regurgitation (compensated heart failure)
Over time, increased left ventricular end-diastolic volume → LV enlargement and eccentric hypertrophy of myocardium → left ventricular systolic dysfunction → decompensated heart failure
what are the clinical features of aortic regurg?
Acute AR
Sudden, severe dyspnea
Rapid cardiac decompensation secondary to heart failure
Pulmonary edema
Symptoms related to underlying disease (e.g., fever due to endocarditis, chest pain due to aortic dissection)
Chronic AR May be asymptomatic for up to decades despite progressive LV dilation Palpitations Symptoms of left heart failure Exertional dyspnea Angina Orthopnea Easy fatigability Syncope Symptoms of high pulse pressure (e.g., head pounding, rhythmic nodding, or bobbing of the head in synchrony with heartbeats- de Musset sign)
what are the clinical features of aortic regurg?
PEXAM:
High pulse pressure
Water hammer pulse of peripheral arteries characterized by rapid upstroke and downstroke
Pulsing of carotid arteries with rapid upstroke and downstroke
Visible capillary pulse (Quincke sign)
Nodding of the head with each pulse
Point of maximal impulse (PMI): displaced inferolaterally, diffuse, and hyperdynamic
Auscultation
S3
High-pitched, blowing, decrescendo early diastolic murmur
AR due to valvular disease: best heard in the left third and fourth intercostal spaces and along the left sternal border (Erb point)
AR due to aortic root disease (e.g., aortic dissection): best heard along the right sternal border
Worsens with squatting and handgrip
Austin Flint murmur
In more severe stages, possibly a harsh, crescendo-decrescendo mid-systolic murmur that resembles the ejection murmur heard in aortic stenosis
Confirmatory tests
Transthoracic echocardiogram (TTE)
Indicated for suspected AR as well as to monitor confirmed AR to determine the staging and optimal timing of surgery
Findings
Abnormal aortic valve leaflets
Regurgitant AR jet on Doppler flow tracing
Increased LV size and volume
Dilated aorta
Fluttering of anterior mitral valve leaflet
Transesophageal echocardiogram (TEE): indicated if suboptimal or nondiagnostic TTE
Screening tests (optional) ECG Signs of left ventricular hypertrophy Chest x-ray Prominent aortic root/arch Enlarged cardiac silhouette
what is the treatment of aortic regurg?
Conservative
Indication: asymptomatic patients and symptomatic patients who are not candidates for surgical treatment
Treatment of heart failure
Physical activity , but without excessive straining
Surgical
Indications
Symptomatic patients with acute severe AR
Asymptomatic patients with:
Chronic severe AR and EF < 50%
Left ventricular systolic diameter > 50 mm
Surgical procedure: aortic valve replacement (occasionally valve reconstruction is possible) and long-term anticoagulation therapy for mechanical valve
