Valvular Diseases Flashcards
What three conditions cause aortic stenosis in adults?
Dystrophic calcification
Bicuspid valve
Rheumatic heart disease
What is the normal relationship between LV and aortic pressures during systole?
Normally no pressure gradient
What are the hemodynamic effects of aortic stenosis?
Peripheral auto regulatory mechanisms maintain BP in aorta so LV pressure increases to maintain gradient and flow across valve
LV undergoes hypertrophy –> pulm congestion and SOB
What are the clinical manifestations of aortic stenosis and what is the average survival after the onset of each?
CHF - 2 years
Syncope - 3 yrs
Angina - 5 years
What are physical exam findings in aortic stenosis other than the murmur?
Pulsus parvus et tardus
Post stenotic dilation of aorta
Cardiomegaly
Pulm congestion
What tests can be used to diagnose aortic stenosis?
Echo is most useful noninvasive
Doppler echo can calculate pressure gradients
Cardiac cath - measures pressure gradient
What sizes of the aortic valve are constitute different types of stenosis?
1.5-2 cm squared - mild
1.0-1.5 cm squared - moderate
Less than 1 cm squared - severe
What are indications for surgery for aortic stenosis?
Recommended for symptomatic severe (.5 cm squared)
Asymptomatic patients even with critical AS by measurement should not have operation until symptoms develop
Symptoms are primary indicator - make sure not to miss any subtle ones
Not contraindicated in elderly patients
What kind of concomitant surgery increase the risk of valve surgery for all types of valve lesions?
CABG
What is the physiology of the mitral annulus?
Fibrous and semi rigid posteriorly
Thinner anteriorly and and continuous with aortic valve annulus
What is normal mitral valve area?
4-6 cm squared
What is the main cause of mitral valve stenosis?
Rheumatic heart disease
Avg time from disease to symptoms is 10-30 yrs
What are the hemodynamics of mitral valve stenosis?
Pressure gradient generally doesn’t occur until valve area less than 2 cm squared
Dilation of LA and a fib
Passive increases in pulm art pressure
Increased HR reduces time in diastole for filling and causes LA pressure to rise
What are clinical manifestations of mitral valve stenosis?
First develop symptoms during tachycardias
Mild respond well to beta blockers
Moderate to severe require surgery
SOB due to pulm congestion and fatigue due to low CO
LA thrombus and emoblization can lead to stroke
What are physical exam findings in patients with mitral valve stenosis other than the murmur?
Pulmonary hypertension and congestion
Echo is pathognomonic for MS with a hockey stick deformity of anterior mitral leaflet
Cardiac cath can measure and assess risk before surgery
What is the general treatment strategy for patients with mitral valve stenosis?
Alleviating symptoms and reducing risk of stroke
Beta blockers control tachycardia that provokes symptoms
Diuretics can relieve pulm congestion
Antiarrhythmics
Anticoagulants in all patients with a fib or with dilated LA or prior embolic events to reduce stroke risk
When should surgery for mitral valve stenosis be considered?
Symptomatic patients with mitral valve area <1.2 cm squared
Open commissurotomy is preferable to MVR
Balloon mitral valvuloplasty slightly superior to open commissurotomy - ideal patient has pliable leaflets, minimal thickening, and little involvement of subvalvular apparatus