Mitral regurgitation

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Background

  • Annual incidence of degenerative Mitral Valve (MV) disease ~3% in industrialized countries causing MR[1]
MV Anatomy in PSS
MV Anatomy in PSL
MV Anatomy in Apical
  • Other etiologies of MR:
  • Criteria for MV repair[2]:
    • Development of NYHA class II symptoms
    • Deterioration in LV function
    • LV end systolic diameter < 4.5 cm with EF > 60% to protect LV function[3]
  • However, recent evidence suggests best outcomes of MV repair are in asymptomatic or minimally symptomatic patients selected for surgery soon after echo dx[4]

Clinical Features

  • Heart failure symptoms
  • Atrial dilatation and atrial fibrillation
  • Pulmonary hypertension
  • Ischemic mitral incompetency, following myocardial infarction or LV aneurysm
    • Most common mechanism of MR in developed countries
    • Dysfunction of ventricular wall leads to papillary muscle dysfunction
    • Posterior papillary muscle and supporting ventricular wall most commonly affected

Differential Diagnosis

Valvular Emergencies

Evaluation

  • Clinical history and exam
    • Most common cause is papillary / chordae rupture after MI in first week[5]
    • Myocardial infarction, endocarditis, trauma
    • Dyspnea, tachycardia, pulmonary edema
    • Suspect if new-onset pulmonary edema, alongside normal heart size
    • Cardiogenic shock
    • S4, apical systolic murmur
    • Clinical evaluation with auscultation may underestimate MR severity[6]
  • Echo grading
    • Traditional grading is different from ischemic MR grading
      • Eyeball grading of color jet from 1+ to 4+, set to color gain that minimizes background noise
      • Color jet area in atrium during maximal MR jet, obtain both PSL and apial 4 chamber, at Nyquist limit scale set of 60 cm/s
MR Grading by Eyeball of Color Jet
MR Grading by LA Maximal Jet Area
    • Ischemic MR grading based on lesion severity of papillary muscle
    • Factors that increase MR grading severity
    • Mitral valve anatomy and scalloping much better appreciated in TEE over TTE

Management[7]

  • Consult Cardiology and/or CT Surgery
  • Supportive measures until definitive surgery
  • Appropriate treatment if myocardial infarction to include cath or thrombolysis
  • Pulmonary edema
    • Oxygen
    • Nitrates and diuresis may improve filling pressures and treat edema
    • Early intubation for impending respiratory failure
  • Decrease afterload
    • Nitroprusside can be considered in normotensive patients to increase cardiac output and decrease MR
    • Intra aortic balloon pump may decrease afterload, increase forward cardiac output and reduce regurgitation
  • Inotropes
    • Dobutamine pressor of choice as α agonism and increased afterload minimal compared to beta agonism[8]
    • Do not alleviate tachycardia with beta-blockers as mild to moderate tachycardia allows less time for LV to backfill

See Also

References

  1. Kouchoukos NT. Problems in mitral valve replacement. In: Kirklin TW. eds. Advances in Cardiovascular Surgery. Grune & Stratton, New York,1973:205-16.
  2. Adams DH, Anyanwu AC. Seeking a higher standard for degenerative mitral valve repair: begin with etiology. J Thorac Cardiovasc Surg 2008;136:551-6.
  3. Mohan JC and Mohan V. Subclinical left ventricular systolic dysfunction in chronic mitral regurgitation and its potential impact on management: quo vadis? Indian Heart J. 2012 May; 64(3): 249–253.
  4. Anders S, Said S, Schulz F, et al. Mitral valve prolapse syndrome as cause of sudden death in young adults. Forensic Sci Int 2007;171:127-30
  5. Kosowsky JM: Infective Endocarditis and Valvular Heart Disease, in Marx JA, Hockberger RS, Walls RM, et al (eds): Emergency Medicine: Concepts and Clinical Practice, ed. 7. St. Louis, Mosby, Inc., 2010, (Ch) 81: p.1072-1074.
  6. Mitral Regurgitation, Ahmed MI, McGiffin DC, O'Rourke RA, Dell Italia LJ. Current Problems in Cardiology Volume 34, Issue 3, March 2009, Pages 93–136
  7. DiSandro D et al. Acute Mitral Regurgitation Treatment & Management. eMedicine. Dec 28, 2015. http://emedicine.medscape.com/article/758816-treatment.
  8. Sonoda M et al. Effects of Dobutamine Infusion on Mitral Regurgitation. Echocardiography. 1998 Jan;15(1):13-20.