Aortic Stenosis Risk Factors & Etiology
What is the most common congenital cause of aortic stenosis?
Bicuspid aortic valve
What is the protein affected in Heyde syndrome?
von Willebrand factor (vWF) multimers
55-70%
What chamber enlarges in AS?
Left atrium
What is the first-line diagnostic test for aortic stenosis?
Echocardiogram
What is the inheritance pattern of bicuspid aortic valve?
Autosomal dominant with incomplete penetrance
How does the LV adapt to aortic stenosis?
What is the triad of aortic stenosis?
Angina, syncope, dyspnea
What are the ECG finding of LA enlargement
Biphasic P wave in V1
What 2 conditions define Heyde syndrome?
Aortic stenosis + GI bleeding (angiodysplasia)
What are two major acquired causes of aortic stenosis?
Calcific degeneration and rheumatic heart disease
What is the primary hemodynamic problem in aortic stenosis?
Increased afterload
What classic murmur description is associated with aortic stenosis?
Crescendo-decrescendo systolic murmur
(murmur due to turbulent flow cause by high pressure gradient between LV pressure and aortic valve and resulting high velocity of flow = crescendo. As gradient falls with LV relaxation = decrescendo)
How does AFib develop in relation to aortic stenosis?
LA stretch → tissue remodeling and fibrosis → electrical instability
What is the enzyme that cleaves vWF after it is unfolded by shear stress?
ADAMTS13
Which demographic is at an increased risk for developing calcific aortic stenosis and why?
Women > 70 years of age
Describe the mechanism of vWF dysfunction in Heyde
High shear stress across stenotic valve → vWF cleavage
This symptom occurs during exertion due to a fixed cardiac output
Syncope
Which part of the aorta will most likely be impacted by a bicuspid valve?
Ascending aorta = aortic dilation
True or false: GI bleeding improves after aortic valve replacement in patient's with Heyde?
True: Removes shear stress → restores vWF function
Why do bicuspid valves develop stenosis earlier than normal valves?
Abnormal flow → turbulence → inflammatory damage → early calcification
This hormone is released by the ventricles in response to stretch
BNP (B-type natriuretic peptide)
Why does dyspnea occur in patients with aortic stenosis?
Elevated LV filling pressure leads to backup up flow and pulmonary congestion
What causes HF with preserved EF seen in certain patients with aortic stenosis?
Diastolic dysfunction
What is the definitive treatment for symptomatic severe aortic stenosis?
TAVR: trans-aortic valve replacement or SAVR: surgical aortic valve replacement
Which patient demographic has higher prevalence of bicuspid aortic valve?
Men 40-60 years of age
In bicuspid aortic valves, this hemodynamic change leads to endothelial injury and early calcification
Increased turbulent flow (shear stress)
This classic aortic stenosis physical exam finding refers to a weak and delayed carotid pulse
pulsus parvus et tardus
Infective endocarditis
This type of vascular lesion, commonly found in the colon, is responsible for GI bleeding in patients
Angiodysplasia