Mitral stenosis

Question 1

Etiology

Answer 1

Almost always - rheumatic in origin
Rare -
1. Lutembacher‘s syndrome, combination of acquired mitral stenosis and an atrial septal defect
2. congenital mitral stenosis
3. in the elderly, calcification and fibrosis of the valve, valve ring and chordate tendineae
4. carcinoid tumours metastasizing to the lung, or primary bronchial carcinoid.

Question 2

Forms of rheumatic mitral valve

Answer 2

Commissural (30%)
Cuspal (15%)
Chordal (10%)
Combined

Cusps fuse at edges + chordae fusion = structural thickening & shortening

Question 3

hemodynamic abnormalities

Answer 3

• Normal mitral valve orifice is 4.5-6cm²
• When mitral valve becomes stenosed, flow from LA into LV decrease and Cardiac output decrease too.
• When mitral valve orifice is reduced the press in the left atrium increases to help ejection of blood
• The press rise in the left atrium causes hypertension in the pulmonary veins and capillaries
• Venous hypertension thus develops
• In response to the progressively increasing press in the left atrium and in pulm. vein, an active spasm of pulmonary arterioles dev (Kitaev‘s reflex)
• The pressure in pulmonary artery does not correlate with the increasing press in the left atrium
• So called active/arterial pulmonary hypertension develops
• Pressure in the pulmonary artery rises in response to this spasm and can be 2-3 times higher than in aorta
• Pronounced hypertrophy of right ventricle develops in response to considerable rise in the pressure in the
  pulmonary artery
• As the contractile activity of right ventricle later decreases, congestion in greater circulation develops
• Left ventricle slightly reduces in size due to the lesser amount of blood entering it & so, lesser activity.

Question 4

Clinical picture - symptoms and signs

Answer 4

Symptoms
- no symptoms until the valve orifice is moderately stenosed (2 cm2).
-
- Because of pulmonary venous hypertension and recurrent bronchitis, severe dyspnoea develops.
- A cough productive of blood-tinged, frothy sputum, and frank haemoptysis.
- pulmonary hypertension leads to right heart failure and symptoms of weakness, fatigue and abdominal or lower limb swelling - edema (ascites).
- left atrium atrial fibrillation, palpitations. systemic emboli to the cerebral vessels, mesenteric, renal and peripheral. pulmonary embolism. thromboembolic complications - stroke, ischemic limb

• chest pain, ascites
• Ortner‘s sign (hoarseness): Recurrent laryngeal nerve compression by dilated left atrium.
• epigastric pulsation due to hypertophy of right ventricle.
• right ventricular failure - hepatic enlargement, engorgement of the neck vein, edema of the legs

Signs
1. Face–mitral facies or malar flush. bilateral, cyanotic or dusky pink discoloration the upper cheeks - infantilism - childhood stenosis
2. Pulse–small-volume (pulsus parvus) pulse, atrial fibrillation resulting irregular pulse. pulsus differens
3. Jugular veins–If right heart failure develops, there is obvious distension of the jugular veins.
Palpation–tapping impulse felt parasternally on the left side. diastolic thrill
percussion - displacement of upper border of relative dullness
4. Auscultation–loud first heart sound if the mitral valve is pliable, but not in calcific mitral stenosis.
‗opening snap‘. low-pitched ‗rumbling‘, mid-diastolic murmur at apex, murmur louder at end of diastole.
5. In pulmonary hpt
- accentuated S2 over the pulmonary artery
- diastolic murmur at the left side of the sternum (Grahm‘s Steel‘s murmur)

Question 5

investigations - ECG , US , X-RAY

Answer 5

1. ECG :
   - P-Mitrale (left atrial hypertrophy).
   - Right ventricular hypertrophy. In pulmonary hypertension : tall peaked P waves in lead II & upright in V1, right ventricular hypertrophy.
2. US :
   - estimate transvalvular gradient & mitral orifice size (moderately severe
   stenosis (<2cm2), Severe stenosis (<1cm2), the presence & severity of disease.
   - the extend of restriction of valve leaflets, thickness, degree of distortion of subvalvular apparatus.
   - assess size of cardiac chambers (left AV orifice will be decreased)& left ventricular function.
3. X-Ray :
   - prominence pulmonary arteries, dilatation of upper lobe of pulmonary veins & backward displacement
   of the esophagus by an enlarged left atrium.
   - In severe stenosis, all chambers & vessels upstream to the narrowed valve are prominent.
   - Kerley B lines are fine, dense, opaque, horizontal lines that are prominent in lower & midlung fields.

Question 6

Indications for surgical treatment

Answer 6

• If pulmonary hypertension develops or the symptoms of pulmonary congestion persist.
• severe narrowing of the mitral valve.
• develops complications such as severe atrial fibrillation, systemic embolization, right ventricular failure,
  tricuspid regurgitation, uncontrollable pulm. edema, limiting dyspnea, pulm. HT, RV HT