Aortic stenosis Flashcards
What is the most common cause of aortic stenosis in patients over 65?
Idiopathic degenerative calcification (wear and tear)
What is the most common congenital cause of aortic stenosis?
Bicuspid aortic valve, often presenting earlier in life. For example, Turner Syndrome (45,X), Noonan Syndrome, Congenital Adrenal Hyperplasia (CAH), 46,XY Disorders of Sexual Development (DSDs).
Bicuspid aortic valve (AV) is one of the most common (about 1% of the population) types of congenital heart disease. It can occur sporadically or as an autosomal dominant inherited disorder with incomplete penetrance. Patients with uncomplicated bicuspid valves typically have an ejection murmur and a sound or click best heard at the lower left sternal border. Chest x-ray is usually unremarkable but can occasionally reveal AV calcification, aortic enlargement (due to aneurysm), or rib notching (due to coarctation). Transthoracic echocardiogram is recommended for diagnosing bicuspid AV and for follow-up. First-degree relatives also should be screened for bicuspid AV to avoid complications including severe regurgitation, stenosis, ascending aorta or aortic root dilation, and dissection. Patients are at increased risk for endocarditis due to abnormal valve anatomy and function; however, routine antibiotic prophylaxis is not recommended.
What is the rare but possible rheumatic cause of aortic stenosis?
Rheumatic heart disease leading to commissural fusion
How does left ventricular hypertrophy develop in aortic stenosis?
Due to chronic pressure overload leading to concentric hypertrophy
What type of murmur is heard in aortic stenosis?
Mid to late systolic crescendo-decrescendo ejection murmur, best heard at the right second intercostal space, radiating to the carotids
How would increased afterload change the intensity of the murmur associated with aortic stenosis?
Decrease in intensity.
Why does handgrip have a depreciating effect on the murmur associated with aortic stenosis?
Decreases intensity due to increased afterload reducing the transvalvular gradient
What maneuvers increase the intensity of the aortic stenosis murmur?
Squatting, leg raise (increase preload), and decreased afterload (amyl nitrite)
How does inspiration, Valsalva, and abrupt standing alter the murmur associated with aortic regurgitation?
Less blood = less murmur
How does the aortic stenosis murmur change with Valsalva?
Either softens or remains unchanged
What is the significance of a soft S2 in aortic stenosis?
Indicates severe stenosis due to immobile aortic valve leaflets, there is often a paradoxical splitting that occurs. In normal physiology, inspiration pulls blood into the right side of the heart and results in delayed closure of the pulmonic valve and slightly earlier closure of the aortic valve; a noticeable split of the aortic (A2) and pulmonic (P2) components of S2 can be appreciated. However, in severe AS, closure of the aortic valve is delayed, which can result in a single S2 during inspiration (due to nearly simultaneous closure of the aortic and pulmonic valves) or paradoxical splitting of S2 (due to A2 occurring noticeably after P2). A loud S2 is heard with mild to moderate aortic stenosis.
Is Erb’s point useful for auscultating aortic stenosis?
No, Erb’s point is more associated with aortic regurgitation and S2 splitting, not aortic stenosis.
What is the meaning of ‘parvus et tardus’?
Weak and delayed carotid upstroke due to fixed left ventricular outflow obstruction, this is a common feature in aortic stenosis.
Where is the PMI located in aortic stenosis?
Sustained and displaced PMI due to left ventricular hypertrophy
What is the classic triad of symptoms in aortic stenosis?
SAD: Syncope, Angina, Dyspnea (heart failure)
What is the first-line diagnostic test for aortic stenosis?
Transthoracic echocardiogram (TTE)
What are the echocardiographic criteria for severe aortic stenosis?
Aortic valve area ≤1.0 cm², mean transvalvular gradient ≥ 40 mmHg, peak velocity ≥ 4.0 m/s.
What are the indications for aortic valve replacement (AVR)?
Severe symptomatic stenosis, asymptomatic with LVEF <50%, undergoing cardiac surgery for another reason, or abnormal exercise stress test
When is balloon valvuloplasty is indicated for aortic stenosis?
Balloon valvuloplasty serves as a bridge to AVR/TAVR in high-risk or unstable patients. This measure can also be implemented in both symptomatic and asymptomatic (if they plan to become pregnant or participate in competitive sports) young adults when the following criteria are met: 1) Aortic stenosis, 2) No significant AV calcification or aortic regurgitation, 3) Peak gradient >50 mm Hg. This is a temporizing measure used to postpone the need for open-heart surgery. Balloon valvuloplasty is reserved for patients who either cannot undergo immediate valve replacement or have special circumstances (young age or pregnancy). It is not routinely used in typical older adults with degenerative AS except as a temporizing measure, because its effects are transient. In adults with calcific AS, BAV yields only short-lived improvement and a high rate of restenosis, so its role is confined to “critical aortic stenosis in patients who are not surgical candidates.
What are the two main types of aortic valve replacement?
Surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR)
Who qualifies for TAVR instead of SAVR?
Older patients or those with high surgical risk
Who requires antibiotic prophylaxis for endocarditis after AVR?
Patients with prosthetic valves, prior endocarditis, unrepaired cyanotic congenital heart disease, or cardiac transplant with valve disease
What procedures require antibiotic prophylaxis for patients with prosthetic valves?
Dental procedures with gingival manipulation, respiratory tract surgery, and infected genitourinary or gastrointestinal procedures
What antibiotic is recommended for endocarditis prophylaxis before dental procedures?
Amoxicillin (or clindamycin if penicillin-allergic) 30-60 minutes before procedure
What is the prognosis for untreated severe symptomatic aortic stenosis?
Poor, with average survival of 2-3 years after onset of heart failure, syncope, or angina
