Mitral Valve Regurgitation (MR)

by | Jul 31, 2015 | Cardiology |

Mitral Valve Regurgitation (MR)

 

Acute MR:

Acute MR Symptoms:

  • Acute severe shortness of breath
  • “Bolt-upright” position in bed
  • Apical tapping
  • Chest discomfort

Acute MR Signs:

  • Hypotension, tachycardia, LV apical tapping
  • Soft, subtle systolic murmur
  • +S3, S4
  • Rales in lungs

Echocardiography in Acute MR:

  • TTE may fail to detect severe acute MR, progress to TEE or cath on clinical suspicion

Treatment of Acute Symptomatic Severe MR:

  • Vasodilators (sodium nitroprusside or nicardipine)
  • Intra-aortic balloon pump (IABP)
  • Surgical repair/replacement stat
    • Papillary rupture
    • Dehisced mitral prosthesis
    • Infective endocarditis + heart failure
    • Chordal rupture (soon if not stat)

 

Chronic MR:

Chronic MR Symptoms

  • Prolonged asymptomatic period, followed by:
  • Pulmonary congestion, dyspnea on exertion
  • Palpitations

Chronic MR Signs:

  • Pulmonary rales
  • S3
  • Tapping apical impulse
  • High-pitched late holo-systolic murmur (sounds like wind in a microphone)
  • Holo-systolic murmur best appreciated at apex in left-lateral decubitus position
  • Loud P2
  • Possible mid-systolic click (MVP)

Chronic MR Epidemiology:

  • Primary MR (organic):  #1 cause is degenerative disease,  #2 rheumatic disease
  • Secondary MR (functional):  dilated CMP, ischemic CMP
  • Chronic MR is pure volume overload –> increased preload,  decreased afterload
  • LV dysfunction occurs before symptoms, so surgical decision is based on LVEF, ESD rather than symptoms
  • LVEF DROPS after repair/replacement surgery
  • Hypertension aggravates MR

Echocardiographic Findings of Chronic MR:

  • Echocardiographic indications for surgery:  LVEF < 60% or ESD > 40 mm
  • Other signs of severe MR:  regurg. vol > 60 mL,  regurg. fraction > 55%,  ERO > 0.4 cm(2), PV systolic reversal, VC > 0.5 cm
  • Note:  chronic MR cannot be severe with normal LVEF and normal LV dimensions
  • Note:  ERO is not accurate in late systolic prolapse of MV (assumes holosystolic regurgitation)
  • Regurgitant jet direction gives indication of etiology:
    • Away from leaflet:  MV prolapse
    • Central MR jet:  annular dilatation
    • Hugging posterior LA:  posterior wall ischemia
  • PISA is an accurate way to calculate MR:    ERO = MV regurg vol / MV TVI  = 2πr(2) x alias-velocity/MR-velocity
  • Cardiac MRI or TEE is indicated for chronic primary MR when TTE does not yield satisfactory information

Catheterization in Chronic MR:

  • Acute MR will have giant v-waves on PCWP
  • Chronic MR will lose giant v-waves on PCWP
  • Protocol:  RHC (RAP & PCWP),  LHC (LVEDP),  C.O. (either Fick or thermodilution), LV gram, +/- nitroprusside

Chronic MR and Exercise Testing:

  • Exercise hemodynamics (Doppler echo or cath) is reasonable when discrepancy between Sx and MR severity at rest

Chronic MR Treatment:

  • Surgical Indications for Severe Chronic MR
    • Any symptoms (Class II-IV symptoms) and LVEF > 30%
    • LV Dysfunction:  LVEF < 60%,  ESD > 40 mm
    • Prophylactic repair in experienced centers for asymptomatic severe MR before LV dysfunction or Sx
    • Surgical contraindications:  LVEF < 25%, multiple comorbidities
    • Repair is preferable to replacement for chronic severe MR limited to posterior leaflet or anterior leaflet, or both if successful/durable repair is likely
    • Severe asymptomatic MR + new AF
    • Severe asymptomatic MR + PHTN > 50 mmHg
    • No need to operate early for secondary (functional) MR, try med Rx (beta blockers, ACEI) first
  • Medical therapy:  vasodilators are contraindicated for chronic MR but who are normotensive, asymptomatic, and normal LVEF

 

Mitral Valve Prolapse (MVP):

  • Non-ejection click, occurs mid-late systole (later than ejection clicks), dynamic nature
  • MVP occurs earlier during standing (valve redundancy)
  • MVP occurs later during squatting (larger LV volume)
  • Supine position causes mid-click

 

References:

Enriquez-Sarano M, Akins CW, Vahanian A.  Mitral Regurgitation.  Lancet.  2009;373: 1382-94.

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

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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