Skip to content

Mitral Stenosis

Mitral Stenosis, Native

Pathophysiology

  • Leads to blood flow obstruction between left atrium and the LV
  • Causes backflow from the LA, leading to elevated left atrial and pulmonary vascular pressures
  • Progressive obstruction can lead to LA enlargement or atrial fibrillation

Pathology

  • Rheumatic Fever from GAS is the MCC of mitral stenosis
    • History of Rheumatic Heart Disease > Mitral annular calcification, SLE, RA, Radiation, Mucopolysaccharidosis, Carcinoid Syndrome, Myxoma, Amyl Nitrite, Endocarditis
    • Antibodies cross-react with cardiac tissue
  • Typically occurs in childhood but can happen at any age
  • May be a latent period until symptoms occur (4th/5th decade)

Symptoms

  • Typically begin w/MV area <1.5cm
  • Gradual and progressive worsening dyspnea on exertion, orthopnea, PND
  • Pulmonary edema ± right sided HF (LE Edema)
    • Sometimes causes secondary pulmonary hypertension

Exam

  • Eventually causes backflow into the LA, leading to elevated left atrial and pulmonary vascular pressures ± pulmonary vascular congestion
  • Left Atrial Enlargement ensues
    • Voice hoarseness or cough for Recurrent Laryngeal nerve compression (Ortner Syndrome)
  • Mitral Facies (pink-purple patches on cheeks)
    • Thickened pericardial stripe and splayed atriotrial on CXR
    • Indicates left atrial enlargement or cancer

Murmur

  • Low S1, Opening Snap after S2 best heard at the apex
    • Followed by low-pitched mid-diastolic rumble with presystolic accentuation
    • Tensing of the chordae tendinae and stenotic leaflets
    • S1 is accentuated and can have a snapping quality
  • Loud P2 if pulmonary hypertension develops

Diagnosis

  • CXR: Displacement of the left main bronchus posteriorly or increased severity
    • 70% of these patients develop Atrial Fibrillation due to LA dilation
  • ECG: Systemic thromboemboli, stroke
  • EKG: Partial/complete RBBB, right axis deviation, RVH Atrial enlargement, RV strain pattern
  • Echocardiography: Pulmonary hypertension, dilated RV, tricuspid regurgitation

Treatment

  • Diuretics for volume overload (loop diuretics)
  • Beta-blockers or CCBs to slow ventricular rate and improve diastolic filling
  • Anticoagulation if Atrial Fibrillation develops (warfarin preferred over DOAC in mechanical prostheses)
    • Mechanical valve: Warfarin target INR 2.5-3.5
    • Bioprosthetic valve: Warfarin target INR 2-3 for 3 months, then aspirin if no AF
  • Percutaneous Mitral Balloon Valvotomy (PMBV) for symptomatic patients with suitable anatomy
  • Mitral Valve Replacement if PMBV not feasible or failed