MITRAL STENOSIS

Question 1

Causes (2)

Answer 1

1- Rheumatic heart disease (99%) (commisural fusion, leaflet thickening)
2- Congenital or carcinoid (1%)

Question 2

Pathophysiology (4)

Answer 2

1- Hallmark of MS is increased LA pressure leading to LA dilatation and backup of blood into pulmonary vasculature

2- Exertional dyspnea:
- On exertion there is increased HR and CO —> decreased ventricular diastolic filling time —> less blood in ventricles —> more blood in LA
- This increased the LAP even more (it’s already higher than normal from the mitral stenosis)
- Increased LAP —> back pressure transmitted to pulmonary veins, capillaries, arteries —> increased pulmonary capillary wedge pressure (PCWP)
- PCWP is now higher than the oncotic pressure of plasma —> exudation of fluid into the interstitium —> stiff lung and symptoms of dyspnea

3- Hemoptysis:
- Rupture of pulmonary capillaries and bronchial venous anastomosis
4- Neurological symptoms:
- Stenotic mitral valve —> Increased LAP —> dilatation of the LA —> stagnation of blood in the LA —> Atrial Fibrillation (irregular contraction) —> thrombus formation —> thromboembolism to the brain
- If a MS patient comes to the ER with neurological symptoms (TIA/stroke) —> give warfarin and heparin until INR = 2, then continue warfarin only
- A wave on JVP and S4 and presystolic accentuation disappear in patients with AFib

Question 3

Symptoms (4)

Answer 3

1- General symptoms of heart failure: SOB, fatigue, etc
2- Hemoptysis (due to rupture of bronchial collaterals)
3- Hoarseness (LA pressing on laryngeal nerve)
4- Dysphagia (LA pressing on esophagus)

Question 4

Signs (7)

Answer 4

• Loud S1, normal S2
• Opening snap (after S2)
  
  • sound of sudden movement of anterior mitral leaflet (usually not as calcified as posterior leaflet)
  • in more severe MS, anterior mitral leaflet heavily calcified —> loss of OS
• MS MDM —> rumbling mid-diastolic murmur
• Presystolic accentuation (sound increases before S1)
• Mitral faces (malar rash/flush)
• Pulse = AFib common, low volume
• Apex = tapping, not displaced

Question 5

Clinical signs of severity (5)

Answer 5

• Soft S1
• Longer duration of the murmur
• Shorter S2- opening snap interval
• Disappearance of the opening snap
• Indirect signs: signs of pulmonary hypertension and RHF

Question 6

Diagnosis (3)

Answer 6

1- Chest X-ray:
- Signs of LA enlargement:
- straightening of left heart border (mitralization)
- widened carina
- double density shadow
- +/- signs of pulmonary edema
- LV is normal size (no cardiomegaly)

2- ECG:
- Atrial Fibrillation
- P.mitrale (bifid p-wave) (indicates left atrial enlargement)
- May develop pulmonary HTN —> P.pulmonale (right atrial hypertrophy)
- Possibly RVH (right axis deviation, tall R waves in V1)

3- Echo:
- EF is normal
- Pathology = commisural fusion, leaflet thickening, calcified nodules, shortened chordae, fish-mouth orifice (hockey stick appearance)
- Signs of severity on echo (3)

Question 7

Treatment (3)

Answer 7

• Main indication of treatment is presence of symptoms
• Medical therapy:
  
  • Beta blockers for heart rate control (decrease HR, decrease LAP, increase diastolic filling time)
  • Loop diuretics for fluid overload + salt restriction
  • A.Fib —> lifelong warfarin
  • Don’t give ACEI inhibitors
• Surgery:
  
  • Percutaneous transseptal balloon valvotomy (TSBV) treatment of choice if severely symptomatic or if pulmonary hypertension develops)
  • If there is an LA thrombus, MR, or a heavily calcified mitral valve, TSBV CANNOT be done —> mitral valve replacement

Question 8

Complications (3)

Answer 8

• Pulmonary hypertension, right sided HF (high JVP, dependent edema, tender hepatomegaly, ascites), congestive heart failure
• Acute pulmonary edema
• Atrial fibrillation —> sudden deterioration + systemic embolization