Aortic Valve Disease questions Flashcards
How is severity of aortic stenosis quantified
1) Planimetry–short axis view on 2D echo
2) Continuity equation–total flow of blood that passes through the LVOT is the same as the total flow passing through the aortic valve
3) Gorlin equation– AVA = CO/44.3 x HR x LVET (left ventricle ejection time) x square root of mean gradient.
3 main causes of aortic stenosis and the pathological features of the disease
1) Rheumatic fever— commissural fusion with leaflet thickening and fibrosis, resulting in triangular aortic valve orifice
2) Calcific degeneration— begins at the base of the cusps and progresses toward the leaflet edges with the commissures remaining open
3) Bicuspid aortic valve— cusps are prone to earlier progressive thickening and calcification with age
Describe pathological findings of calcific degeneration
Masses of lipocalcification lying on the aortic side of the valve consisting of
1) inflammatory cell infiltrate (macrophages, T lymphocytes
2) lipids (LDL and lipoprotein A)
3) Microscoptic calcification
4) other proteins
What are signs of aortic stenosis
Pulsus tardus (slow-rising pulse) Palsus parvus (small amplitude pulse) Single heart sound: A2 component is diminished due to calcification and stiffening Paradoxical splitting of the second heart sound (delayed A2) Fourth heart sound---pre-systolic thrust generated from atrial contraction into a hypertrophied and non-compliant left ventricle Crescendo-decrescendo systolic murmur causes by turbulent flow-(not pansystolic) Late peaking of AS murmur indicates its severity rather then intensity
What is low-flow, low gradient aortic stenosis? how is it managed
Patients with low ejection fraction of <40%, a mean gradient of < 30 mmHg, and a calculated aortic vavle area of < 1.0 cm2
Dobutamine stress echocardiography, 5 -20 ug/kg/min of dobutamine administered in increments of 5 ug every 5 minutes and assesses for increase peak pressure gradient and change in EOA.
What are physical signs of Aortic Regurgitation
Widened pulse pressure
Duroziez’s sign-systolic and diastolic murmur audible over femoral arteries
Quinke’s sign-pulsation in the capillary membranes of the fingertips
Traube’s sign-pistol shot sound audible over the femoral artery
De Musset’s sign-head bobbing with a collapsing pulse
Corrigans pulse–water-hammer collapsing pulse
Mueller’s sign–pulsation of the uvula
Hills sign–SBP in the leg greater then SBP in the arm by at least 20 mmHg.
3rd heart sound loudest at apex
Decrescendo diastolic murmur hear best with patient exhaling
Austin Flint–low pitched diastolic murmur occurs because of turbulence across the mitral valve
List surgical options for patients with a small aortic root
Implanting a valve prosthesis with an improved EOA
stentless valve
small sewing ring valve (CE perimount magna)
surpa-annular
Aortic root enlargement with bovine pericardial patch
Aortic annular enlargement
Aortic root replacement
Apico-Aortic valved conduit
What is Freedom from structural valve deterioration for the different aortic valve prostheses
For patients 70 years old at 15 years
1) Mechanical valve 97%
2) Aortic valve homograft 85%
3) Bovine pericardial valve 85%
4) Porcine bioprosthesis 80%
5) stentless bioprosthesis 80%
6) pulmonary autograft (Ross) 74% for the aortic valve and 80% for the pulmonary valve
Structural valve deterioration (SVD) in bioprosthetic valves based on age at 10 years
40% in patients aged 0 - 40 years
30% in patients aged 40 to 69
10% in patients aged > 70 years
Describe other lesions associated with BAV
Short left main stem coronary artery
A left dominant coronary artery circulation
An anomalous position of the coronary ostia
aortopathy
coarctation of the aorta
earlier onset of aortic stenosis
Histological analysis reveals cystic medial necrosis, reduced fibrilin-1 production and elastin fragmentation
List factors to consider when pregnant pt with a mechanical valve insitu
Warfarin crosses the placenta and increases risks of abortion, prematurity, and stillbirth
Warfarin associated with embryopathy in 5-10% of pts but is lower if dose <5mg/day.
Heparin dose not cross placenta but may induce bleeding at uteroplacental junction
Strategy:
warfarin during weeks 1-6
Unfractionated heparin during 6 -12 weeks
warfarin 12 to 36 weeks
UFH from week 36
stop heparin before delivery
How can atherosclerosis of aorta be classified
Type I: Circumferential calcification or “porcelain aorta” Easily palpable
Type II: Diffuse intimal thickening with ragged friable edges. Unreliable to manual palpation, easy to identify by the TEE or epiaortic scan.
Type III: intramural liquid debris. the most difficult to palpation on TEE.
What is natural history of untreated aortic stenosis
Angina –5 years
Syncope–3 years
dyspnea–2 years
What are two posterior root enlargement procedures
Nicks aortic annuloplasty: incision through the middle of non-coronary sinus
Manougian’s aortic annuloplasty: incision pass through the commissure between the left and non-coronary sinuses and onto the anterior leaflet of the mitral valve
What is natural history of patients with untreated AI
6% of asymptomatic patients with good left ventricular function either become symptomatic develop left ventricular dysfunction per year
25% of asymptomatic patients with left ventricular dysfunction develop symptoms per year
symptomatic patients have a 10% mortality per year
How is aortic regurgitation quantified
mild mod Severe Jet width <25 25-65 > 65 Vena contracta 0.6 Regurgitant fraction% <30 30-50 > 50 Regurgitant volume <30 30-60 >60 Effective regurgitant orifice <0.1 0.1-0.3 >0.3
What structures are at risk during aortic valve surgery
Anterior mitral valve leaflet (beneath the non-coronary and left coronary cusps)
Membranous septum: (beneath the non-coronary and right coronary cusps)
Bundle of HIS: (beneath the commissure between the non-coronary and right coronary cusps)
Left and right coronary ostia
What are the surgical approaches to the aortic valve
Oblique aortotomy (J-shaped)
transverse aortotomy
Greater curve aortotomy, which can be combined with an aortoplasty to reduce the size of a moderately enlarged ascending aorta
What are different methods of implanting an aortic valve prosthesis
Interrupted sutures technique, reduced risk of paravalvular leak
Everting suture–place the prosthetic valve in an intra-annular position thereby reducing the relative effective orifice area (EOA) of the annulus allowing a smaller valve to be implanted
Non-everting sutures-place the prosthetic valve in a supra-annular position, thereby increasing the effective orifice area of the annulus, allowing a larger valve to be implanted, relative to the everting suture technique.
Semi-continuous technique, which is faster, but has theoretical increased risk of PV leak.
What is Marfan syndrom
Autosomal dominant variably penetrant inherited disorder; prevalence is 1 in 5000
Mutation in the gene that endocodes fibrillin-1 on chromosome 15
What are the diagnostic (Ghent) criteria for marfan
Family history Mutation of FBN1 Cardiovascular Aortic root dilation Dissection of ascending aorta mitral valve prolapse calcification of the mitral valve dilation of the pulmonary artery dilation or dissection of the descending aorta Ocular ectopia lentis flat cornea myopia elongated globe Skeletal pectus excavatum pectus carinatum pes plans thumb sign scoloisis. or spondyloisthesis arm span > 1.05 pulmonary apical bulla/spontaneous pneumothorax skin unexplained stretch marks/recurrent incisional hernia
What is Loeys-Dietz syndrome
mutations in TGF beta receptors 1 and 2
similar to that of Marfan or more drastic associated with dissection in children.
characterized by the triad of
hypertelorism
bifid uvula/cleft palate
generalized arterial tortuosity with wide spread vascular aneurysm and dissection
What is Vascular Ehlers-Danlos syndrome
rare autosomal dominant inherited disorder of the connective tissue resulting in COL3A1 gene encoding of type III collagen
spontaneous rupture without dissection of large and medium-caliber arteries accounts for most deaths
Aortic root dilation is common
Name other causes of aneusrym disease of aorta
Athersclerotic Infectious (syphilitic) aortitits giant cell Ankylosing spondylitis Reiters sydrome psoriatic artheritis polyarteritis nodosa Behcet's disease
What is natural history of biscuspid aortic valve
Mayo clinic showed at 15 year follow up the 20 year survival was similar to that of the general population but the incidence of surgery on the aortic valve and/or ascending aorta was 27% and the total adverse cardiovascular events was 42%.
