Valvular Heart Disease Flashcards
1
Q
congenital aortic stenosis
A
- Bicuspid – MC
- Person born with two leaflets instead of three
- Theres a strong correlation between bicuspid valve and marfan system which affects the medial layer of the aorta and dissection of the thoracic aorta
- Aortic dissection = MCC death in bicuspid
- Membranous subvalvar – can be very tricky to determine where problem is – occurs a lot in kids
- Fused leaflets with doming – they are flexible but because of the fusion, they dome upward due to the left ventricular systole
2
Q
Acquired aortic stenosis
A
- Acquired – much more common than congenital
- Calcific – leaflets become sclerotic (we don’t know why)
- You can see in renal disease where they have a lot of calcium phosphate
- Hypertrophic subaortic – this is not actually stenosis of valve, but rather beneath it
- Rheumatic – rheumatic fever typically affects the mitral valve
- Calcific – leaflets become sclerotic (we don’t know why)
3
Q
pathophysiology of aortic stenosis
A
- Increased systolic ventricular pressure – this is like a body builder working out – muscle hypertrophies
- First thing that happens is NOT loss of strength
- Left ventricular hypertrophy
- Diastolic dysfunction – ventricle doesn’t relax as much because its so hypertrophied
- Only later does the ventricle poop out because its tired
- Diastolic dysfunction – ventricle doesn’t relax as much because its so hypertrophied
- Systolic decompensation
- Low pulse pressure, hypotension – if the ejection is impeded, the systolic doesn’t rise as high and because the vessels in the periphery are so constricted, the diastolic doesn’t fall as much
4
Q
symptoms of aortic stenosis
A
- Angina (triad #1) – pain in chest from inadequate coronary blood flow
- Theres no obstruction in coronary artery
- There is more demand for oxygen from the hypertrophied ventricle
- EXERTIONAL angina
- Congestive heart failure – constellation of signs and symptoms
- Diastolic – most common presentation with aortic stenosis – the muscle is so hypertrophied that for the ventricle to fill, the left atrial pressure rises and backs up into the lungs
- Systolic
- Presyncope and syncope (Stokes-Adams attacks) – refers to presyncope and syncope caused by hypotension when the left ventricle cant maintain systolic pressure
- Peripheral vasculature for muscles being utilized are still dilated, but as person slows down, there is a dip in blood pressure or loss in consciousness
5
Q
signs of aortic stenosis
A
- Systolic murmur
- Thrill – palpable murmur, theres nothing different between murmur and thrill except that one is heard and one is felt
- If you feel a thrill, because aorta is anterior, you can be pretty sure it is aortic stenosis
- Thrill – palpable murmur, theres nothing different between murmur and thrill except that one is heard and one is felt
- Soft second heart sound
- Delayed arterial upstroke – normally the ventricle has ejected most of the blood, but now it takes longer to get all the blood out
- If you can feel artery filling under your fingertips, that could be an indication of a delayed upstroke
- Narrow pulse pressure
- Rales and other signs of CHF
6
Q
diagnosis of aortic stenosis
A
- Symptoms
- Examination
- Echocardiogram
- Increased leaflet thickness and echodensity with decreased excursion on structural views
- Increased systolic velocity of blood flow (gradient) with reduced valve area on Doppler
7
Q
Echo findings in aortic valve area with aortic stenosis
A
- If you think about cars in a racetrack (oval), the rate of cars crossing past any point in that oval has to be the same or cars would be piling up
- Continuity principle: flow rate is constant regardless of where it is measured
- Flow rate in an orifice is equal to area multiplied by velocity
- A(cm x cm) x V (cm/sec) = CO (cm3/sec)
- Outflow tract flow = Aortic valve flow
- Aortic area X vel. = Outflow area X vel.
- Aortic area = (Outflow area X vel.)/aortic vel.
8
Q
use of cardiac cath in aortic stenosis
A
- Aortic stenosis and coronary atherosclerosis often go hand in hand
- Systolic gradient across valve
- With cardiac output, valve area is calculated
- Echocardiogram superior to cardiac cath for above
- Cardiac cath primarily to evaluate coronaries: CAD frequently accompanies AS
9
Q
Aortic stenosis tx
A
- CHF from diastolic dysfunction may be treated with medication: diuretics
- ONLY diastolic numbers are off – for any of the other classical triad, you have a mechanical problem with imminent trouble
- For any of the classical triad of angina, CHF (from systolic dysfunction), or Stokes-Adams attacks, mechanical intervention:
- Valve replacement – THE SOLUTION
- Balloon valvuloplasty – makes the valve a little more flexible – if you can increase valve area by 50%, results in a huge difference! But, this is not a permanent cure
- Mostly for people who need urgent surgery but have aortic stenosis
10
Q
aortic stenosis valvuloplasty
A
- Only for calcific or rheumatic AS of trileaflet valves
- Respite is temporary, therefore use limited:
- Palliation of nonsurgical candidates
- Stabilization of patients requiring urgent major noncardiac surgery
- Possible reduction of operative M&M during AVR in patients with poor LV contractility (theoretical)
11
Q
aortic stenosis valve replacement
A
- Mechanical: Indefinite durability at the price of chronic anticoagulation
- Heterograft: anticoagulation not necessary (in the absence of AF); durability finite
- From another species – from a pig or constructed using pig endocardium
- Homograft: at one time more durable; rarely used now
- TAVR: Percutaneous delivery of a heterograft valve mounted on a balloon, supported by a stent
- Transcutaneous aortic valve replacement
- Tissue valve is sewn into metallic stent – stent is crimped onto a catheter with balloon on the end – inserted into femoral artery and up to the heart, balloon is expanded, valve is in place
12
Q
Aortic regurgitation: etiology (chronic)
A
- Hypertension (& other root dilatation) – the leaflets no longer coapt during diastole
- Arteriosclerosis
- Aortic stenosis – leaflets are so stiff that they often don’t come together well – results in some regurgitation
- Prosthesis: leaflet vs. perivalvular
- Leaflet – in a mechanical valve, soft tissue can start to grow into the valve region
- Endocarditis can eat through a leaflet or a tear in the leaflet
- Perivalvular – if there is difficulty in surgery, there might be leakage around where the valve was sewn in
- Endocarditis
- Connective tissue diseases, e. g. Marfan’s
- Inflammatory diseases, e. g. RA, SLE
- Congenital disease
- Bicuspid – can become frozen in open position
- VSD – sometimes the jet from the septal defect can affect the aortic valve and cause leaflet malformation
- Sinus of Valsalva aneurysm – the three pouches that are created by the shape of the aortic valve – sometimes they dilate and rupture – most common on right side of the heart
- Aortitis – can cause dilation and regurgitation
- Rheumatic – can stiffen the leaflets into a position where they can’t coapt
- Syphilis
13
Q
aortic regurgitation etiology (acute)
A
- Aortic Dissection
- Endocarditis
- Trauma
- Valve prosthesis
- Rupture of sinus of Valsalva aneurysm
- Rheumatic fever
14
Q
Aortic regurgitation pathophysiology
A
- Blood regurgitates into LV in diastole
- LV maintains net stroke volume by dilating – the stroke volume can double and that is how CO is maintained
- Acute decompensation: pulmonary congestion – the decrease in LV volume has not occurred
- Diastolic pressure rises so high from the leakage, suddenly someone is in CHF (pulmonary edema)
- Chronic decompensation: LV systolic failure – has maintained normal stroke volume but when it tires out and ejection fraction falls, the decompensation occurs
15
Q
Aortic regurgitation sxs
A
- CHF
- Palpitation
- Increased stroke volume
- Arrhythmia
