AS/AI Flashcards
What are risk factors for aortic stenosis?
Increased LDL + DM + HTN + smoking + mediastinal radiation + renal failure + familial hypercholesterolemia + Ca+ metabolism disorders (i.e. hyperPTH) + NOTCH1 mutations
What are the 3 pathophysiological processes that lead to AS?
Degenerative calcification, bicuspid aortic valve, and rheumatic AS
What is the prevalence of bicuspid aortic valves?
1-2%
When does AS in bicuspid valves normally present?
5-6th decade of life
What is LaPlace’s law?
Wall stress = wall tension / wall thickness
What is the classic triad of AS?
SAD = Syncope, angina, dyspnea
Why do you get angina with AS?
Increased O2 delivery is limited due to LVH
What does dyspnea mean with AS?
Indicates that the beneficial effects of LVH to maintain LV function has diminished now and is a harbinger of LV failure
When do you need to do a cardiac cath for AS?
If noninvasive measures are equivocal in a high risk patient or when there is discrepency between clinical symptoms and echo findings
What is the gold standard for sizing valves in TAVRs?
CTA
What is low flow/low gradient AS?
EF<50% or stroke volume index < 35 mL/m2 + AVA < 1.0cm2 + mean gradient < 40 mmHg on TTE
What is classic low flow/low gradient AS?
AVA < 1.0 cm2 + with dobutamine challenge, the CO and SV index rise and mean AV gradient > 40 mmHg
What is the incidence of classic low flow/low gradient AS?
10-15%
What is pseudo low flow/low gradient AS?
Not real AS as there isn’t enough flow to move the AV leaflets; with dobutamine challenge, CO and SV index rise but the AVA increases above 1.0 cm2
What is paradoxical low flow/low gradient AS?
Normal EF (>50%) + decreased SV index (<35 mL/m2) + AV mean gradient < 40 mmHg + AVA < 1 cm2; indexed AVA < 0.6 cm2/m2 confirms diagnosis
What kind of patient normally has paradoxical low flow/low gradient AS?
Elderly patients with LVH + small LV cavity + diastolic dysfunction; seen in 10-25% of AS patients
What are the benefits of a balloon valve angioplasty for AS?
Symptom relief (short, weeks to months) but no survival benefits
What are the indications of a BVA for AS?
Pediatric patients (bridge to surgery) + bridge to TAVR + improving quality of life for non-surgical/TAVR candidates
What are class 1 indications for aortic valve replacement?
Symptomatic AS, classic and paradoxical LF/LG AS, and asymptomatic severe AS undergoing cardiac surgery for other indications
What are the benefits of using a bioprosthetic valve? Downsides?
No anticoagulation; but can undergo structural valve deterioration
What are the benefits of a mechanical valve? Downsides?
Long durability and easy implantation; but requires anticoagulation and can have thromboembolic complications
What are complications seen more commonly with SAVR?
Bleeding + renal failure + atrial fibrillation + respiratory complications
What are complications seen more commonly with TAVR?
Conduction abnormalities + paravalvular leak + stroke + vascular complications + coronary occlusion
Which cusps of the AV are in continuity with the aorto-mitral curtain?
The noncoronary and left coronary cusps
What are the most common causes of aortic insufficiency?
Endocarditis and aortic dissection
How does the LV compensate with AI?
The increased LVEDP due to AI leads to effective decreased stroke volume -> increased HR (decrease regurgitant volume) + increased SVR (increase coronary perfusion pressure)
What happens to the LV with long standing AI?
Eccentric hypertrophy (due to volume overload)
What happens to myocardial work with chronic AI?
Increased due to eccentric (and sometimes concentric) hypertrophy -> can be doubled
What are the 4 stages of aortic regurgitation?
Stage A (at risk), Stage B (progressive -> mild/mod AI), Stage C (asymptomatic severe), Stage D (symptomatic severe)
What stage(s) of AI should you start an ACE/ARB?
Stage C2 (asymptomatic severe with depressed EF or severely dilated LV) or Stage D (symptomatic severe)
What are grade 1 indications for AVR with AI?
Stage D AI (severe symptomatic AI) + Stage C2 (severe asymptomatic AI with depressed LVEF) + Stage C with other cardiac surgery
What other anomalies are seen commonly with a bicuspid aortic valve?
Proximal aortic dilation (40-87%) + aortic dissection (6-9x the risk)
What is Siever’s Classification system for bicuspid aortic valves?
Sievers 0 = no raphe with two cusps; Sievers 1 (most common) = two smaller, malformed cusps forming the raphe and one larger cusps (normally RCC and LCC fusion); Sievers 2 (least common) = LCC-RCC and RCC-NCC fusions forming 2 raphes
Which Siever’s classification for bicuspid AV has the highest risk of aneurysm formation?
Sievers 2; due to flow direction and increasing local wall stress
What is the effective height of the AV?
The ideal height for repair measured from the aortic annulus to free margin of each aortic cusp in diastole (> 8mm)
What is the geometric height of the AV?
Curved length measured from the aortic annulus to the central part of the free margin (ideally > 20mm)
What is the coaptation height of the AV?
The amount of leaflet coaptation during diastole (normally 2-5mm)
What is the El Khoury Classification?
Functional, repair-centered classification of AR
What is a Type I El Khoury classification?
Normal cusp motion: Ia = dilated distal to STJ (tx = STJ remodeling and ascending aortic graft); Ib = dilation from annulus to proximal ascending dilation (tx = valve sparing root replacement); Ic = aortic annulus dilation (tx = subcommisural annuloplasty); Id = hole in AV (tx = patch repair)
What is a Type II El Khoury classification?
Cusp prolapse; treatment = prolapse repair
What is a Type III El Khoury classification?
Cusp restriction; treatment = leaflet repair
When do you fix the aorta with asymptomatic bicuspid aortic valve?
If aortic root or ascending aorta > 5.5cm OR > 5.0cm with risk factors, low perioperative risk, and access to experienced aortic center
When do you fix the aorta with symptomatic bicuspid aortic valve?
Aortic root or ascending aorta > 4.5cm
Can you do a TAVR for AI?
Difficult because the aortic annulus/root might be dilated -> high risk for valve migration and paravalvular leak
