Mitral Valve Stenosis (MS)

by | Jul 29, 2015 | Cardiology |

Mitral Valve Stenosis

Symptoms/History:

  • Dyspnea at rest, dyspnea on exertion (DOE)
  • Paroxysmal nocturnal dyspnea
  • R-sided HF symptoms:  slow progressive orthopnea, fatigue, edema
  • Hemoptysis
  • Atrial Fibrillation, palpitations, resultant emboli (stroke/TIA)
  • Potential history of rheumatic fever as a child

MS Physical Exam:

  • Loud S1, loud P2
  • High pitched opening snap followed by a low-pitched holodiastolic rumble at the apex
  • RV lift
  • Liver edge may be palpable in R-HF
  • Possible atrial fibrillation

MS Etiology/Epidemiology:

  • MS almost always results from rheumatic fever
  • Prolonged inflammation causes commisural fusion, diastolic leaflet doming
  • Resultant increase in LA pressure causes LA enlargement, pulmonary hypertension, R-HF, atrial arrhythmias
  • LV is usually unaffected in pure MS;  there is pressure overload in LA, RV, RA, and pulmonary circulation
  • Differential Diagnosis for Mitral Stenosis:  cor triatriatum, atrial myxoma, PV obstruction

Mitral Stenosis Stages:

  • A:  At risk (mild valvular doming)
  • B:  Progressive
  • C:  Asymptomatic severe MS (MVA < 1.5 cm(2), PHT > 150 msec, very large LA,  PASP > 30 mmHg)
  • D:  Symptomatic severe MS (above, with reduced exercise tolerance and DOE)

Chest X-ray in MS:  enlargement of left and right atria, pulmonary congestion, LV normal size

  • Barium swallow study may show esophagus is “pushed-back” due to LA size

Echocardiogram in MS:

  • Echo Doppler of the mitral valve gradient is the gold standard for diagnosis of mitral stenosis & severity
  • Findings of MS on echo:  commisural fusion, increased LA size, diastolic doming, hockey stick appearance, candle-flame appearance of MS jet on Doppler, M-mode with A/P thickening and moves as one unit
  • Severe mitral stenosis:  gradient > 5-10 mmHg, MVA ≤ 1.5 cm(2), PHT > 150 msec
  • Echo is better for evaluating MS, cath is limited by PCWP dampening, cath may need trans-septal puncture
  • MVA = 220/PHT = 0.29 DT
  • MVA = ( LVOT TVI x LVOT A )  /  MV TVI
  • Exercise echo (bike vs. TM) can be used if there is a discrepancy between symptoms and calculated area or gradient.  Of note, gradient is highly dependent on heart rate
  • Wilkins Echo Scoring System for Percutaneous Mitral Balloon Valvuloplasty (PMBV):
    • 4 components:  mobility, subvalvular thickening, valvular thickening, calcification
    • Grade each component 1-4.  component x grade = score
    • PMBV candidate with echo score < 8
    • Surgical MVR if score > 10
  • TEE is useful for pre-PMBV evaluation to r/o thrombus and confirm MS severity

Treatment of Mitral Stenosis:

  • Intervene for HF class III-IV symptoms
  • PMBV for Wilkins score < 8
    • Severe symptomatic MS & pliable MV
    • Asymptomatic with severe MS and PAP > 60 mmHg
    • Severe MS & new AF (regardless of Sx)
    • Exercise with PCWP > 25 mmHg or MV gradient > 15 mmHg
    • Inoue technique most popular
    • Pre-op TEE to r/o LAA thrombus
    • PMBV contraindications: MR > 2+,  LA thrombus,  unsuitable valve (score > 10)
  • Surgical MVR for Wilkins score > 10
    • Poor PMBV candidates
    • Significant MR (>2+)
    • Significant stroke despite anticoauglation
    • Mod-severe MS who is undergoing other cardiac surgery
  • Anticoagulate for the following situations:
    • MS + AF
    • MS + prior embolism/stroke
    • MS + LA thrombus

Special Considerations: Pregnancy and Mitral Stenosis

  • Symptoms usually present in 2nd trimester of pregnancy (13-27 weeks)
  • PMBV is indicated in III/IV Sx refractory to medical management
  • Med Rx:  beta blockers, maintain NSR  –> progress to PMBV, open valvotomy –> MVR

Special Considerations: Rheumatic Disease Primer

  • Most common in “developing” countries, uncommon in the US/Europe currently
  • Peak incidence in children 5-15 y.o. and less common with increasing age up to 5th decade
  • Approximately 3% of patients with group A streptococcal pharyngitis will develop RF
  • Abnormal host immune response is thought to be associated with RF and development of rheumatic MS
  • Jones Criteria for Rheumatic Fever:
    • Major Criteria:
      • Carditis (sinus tachycardia, MR murmur, S3, pericardial friction rub, cardiomegaly, pericardial calcification)
      • Migratory polyarthritis
      • Sydenham’s chorea
      • Subcutaneous nodules
      • Erythema marginatum
    • Minor Criteria:
      • Fever
      • Arthralgia
      • Elevated acute phase reactants (lab)
      • Prolonged PR interval on ECG
    • Positive Jones Criteria is 2 Major OR 1 major 2 minor, Plus:  supporting evidence of a recent group A streptococcal infection  (+ throat Cx, rapid Ag detection test, increasing/elevated streptococcal antibody test ASO)
  • Mitral valve most commonly affected by ARF, followed by aortic valve
  • Treatment:  Oral Penicillin V (IM 1.2 million U)
  • Secondary Prophylaxis:  IM Benzathine penicillin G every 4 weeks, or oral penicillin V 250 mg bid, or oral sulfadiazine 1 g daily
  • Arthritis treatment with salicylates

 

References

Chandrashekhar Y, Westaby S, Narula J.  Mitral Stenosis.  Lancet.  2009;374: 1271-83.

Feldman T and Grossman W.  “Profiles in Valvular Heart Disease.” Chapter 28 in Cardiac Catheterization, Angiography, and Intervention.  New York:  Lippincott Williams & Wilkins, 2006.

Kaplan EL.  “Rheumatic Fever.”  Chapter 302 in Harrison’s Principles of Internal Medicine.  New York: McGraw-Hill, 2005.

Nishimura RA, et al.  2014 AHA/ACC Guideline for the Management of Patients with Valvular Heart Disease.  J Am Coll Cardiol. 2014 Jun 10;63(22):2438-88.

Oh JK, Seward JB, and Tajik AJ.  The Echo Manual.  New York: Lippincott Williams & Wilkins, 2007.

 

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