Cardiac Surgery
Lec : 2
Mitral Valve Disease:
1.Mitral stenosis:
Etiology:-
1.Rheumatic heart disease. 2. Calcific degeneration.
3. Cardiac Tumor like left atrial myxoma 4. Congenital mitral stenosis
Pathophsiology:-
The development of mitral stenosis is usually progressive in which the normal surface area
of valve decrease from 4-6 cm
2
to about 1-1.5 cm
2
at this stage it is called Moderate mitral
stenosis and patient become symptomatic . When valve surface area decrease to 0.8 cm
2
the condition called Severe mitral stenosis.
Mitral stenosis lead to increase in the left atrial pressure leading to pulmonary venous
congestion and pulmonary hypertension this produce left atrial dilatation and atrial
fibrillation this will decrease the volume of blood which pass from the left atrial to left
ventricle which depend mainly on the left atrial contraction therefore left ventricle end
diastolic volume decrease and stroke volume and cardiac out put decrease also.
Clinical Features:-
1.exertional dyspnea 2. decrease exersice capacity
3. orthopnea 4. paroxysmal nocturnal dyspnea
5. pulmonary oedema 6. atrial fibrillation 7. embolic episode
auscultation :
1.Loud first heart sound. 2.Diastolic murmur at cardiac apex.
Diagnosis :
by echo which shows:
1. Valve surface area 2.Transvalvular pressure gradient.
2. Asses leaflet mobility, calcification and subvalvular fusion.
Mangement:-
1. Mitral valve repair: two methods
A. Percutaneous balloon valvoplasty
B. Open mitral commissurutomy: it allows mobilization of fused papillary muscles and
removal of left atrial clot. It can be done for patient with moderate mitral stenosis
with non calcified valve.
2. Mitral valve replacement: TYPES of available valve
A. Mechanical bileaflet valve: This require life-long anticoagulation with warfarin
,suitable for young patient with long life expectancy, require careful INR monitor
which must be kept between 2-3
B . Tissue valve ( either bovine or porcine ):
1.does not require warfarine therapy.
2. sutible for old patient and young female who desire to be pregnant .
3. durability is between 5-10 years, sometimes re-operation may be needed.
. Mitral valve insufficiency:
Etiology :-
1.Degenerative disease 50-60 % 2.Rheumatic fever 15-20 %
3.Ischemic disease 15-20 % 4. Endocarditis
5.Congenital abnormalities 6. Cardiomyopathy
Pathology:
The mitral valve composed of :-
1.Annulus, 2. Leaflets, 3.Chordae, 4. Papillay muscles.
A defect in any one of these components may create mitral insufficiency.
Pathophysiology:
The regurgitation of part of left ventricle stroke volume into left atriam will decrease
forward blood flow and increase left atrial pressure leading to pulmonary congestion and
volume over load on left ventricle, this will lead to dilatation of both left atrium and left
ventricle.
Clinical features:
In acute Mitral Regurgitation symptoms of congestive heart failure may develop
suddenly.
In chronic cases patient complains from exertional dyspnea ,decrease exercise capacity
which progress to pulmonary congestion and left ventricle dysfunction, on auscultation
apical pansystolic murmur radiate to axilla.
Diagnosis : by echo which shows
1. Site of pathology in the valve . 2. Size of cardiac chambers.
3. The volume of forward cardiac output.
Indications for surgery:
1. Symptomatic patient. 2. Recent onset of Atrial fibrillation.
3.Asymptomatic patient with ejection fraction less than 50%(severe mitral insufficiency).
Operative Methods:
1.Mitral valve replacement when the valve is severely damaged.
2.Mitral valve repair when there is minimum damage to valve element, this can be
done by one or combination of the following procedures .
a. Commissurotomy to free fused leaflets from each other.
b. Annuloplasty to correct the size of dilated annulus .
c. Suturing of perforated leaflets.
d. Repair of damaged chordae or rupture papillary muscle .
Aortic valve disease
1. Aortic stenosis:
Etiology:-
1. Congenital 30 % (bicuspid valve ). 2. Rheumatic disease 10-15 %.
3. Calcific valve stenosis 60 % (degenerative disease ).
Pathophsiology:-
Aortic stenosis laeds to reduction in the ejection fraction and increase transvalvular
pressure gradient and increase myocardial work load producing left ventricle
hypertrophy.
.Normal aortic valve has cross sectional area 2.5-3.5 cm
2
.Moderate aortic stenosis 1.2-1 cm
2
.Severe aortic stenosis 0.8 cm
2
or less
Clinical features:-
1.Decrease exercise capacity. 2.Heart failare . 3.Angina. 4.Syncope.
Diagnosis:-
By Echo which shows :
1. measure transvalvular pressure gradient.
2. Calculate valve surface area.
3. Measure blood flow velocity across the valve.
4. Show the degree of leaflet immobility and left ventricle hypertrophy.
Indication for surgery:
1. Symptomatic patient.
2. Asymptomatic patient with moderate to severe aortic stenosis .
Operative methods:- Aortic valve replacement by either :
1. Mechanical valve which requires life long warfarin.
2. Autograft valve in which pulmonary valve is harvested and implanted instead of
aortic valve togeather with coronary artery re-implantation and homograft tissue
valve is put in the pulmonary area(Ross procedure).
Aortic Reguergitation
Etiology:
-
1.degenerative diseases. 2.endocarditis. 3.rheumatic heart diseases
4.conginital. 5.aortic root dilatation.
Pathophiology:-
Blood will return from aorta to left ventricle during diastolic phase
producing left ventricular volume overload and dilatation
Clinical features:-
1.Dyspnea on exertion. 2.Palpitation. 3. Wide pulse pressure
4. Angina due to decrease diastolic pressure which reduce coronary perfusion
5.Diastolic murmur in left third intercostal space when patient lean forwards.
Diagnosis:-
By echo:
1. Measures the degree of valvular insufficiency. 2.Measures left ventricle size.
Indications for surgery:-
1. Symptomatic patient.
2. Asymptomatic patient with severe Aortic insufficiency.
Aortic valve is replaced with mechanical valve with life long warfarin therapy.