Transcript Document

Mitral Regurgitation
Francesca N. Delling, MD
July 8, 2009
Outline
 Anatomy
 Diagnosis
- Two-dimensional echocardiography (etiology)
- Doppler methods (assessment of severity)
- Role of 2D and 3D-TEE
- Role of CMR
 Treatment
Anatomy: The mitral valve apparatus
 Subvalvular apparatus
(papillary muscles with
their supporting left
ventricular walls and
chordae tendineae)
 Mitral annulus
 Mitral valve leaflets
Anatomy: The mitral valve
 Reference view from the
left ventricular apex
 Surgical view from the
left atrium with the heart
rotated
Diagnosis
2D Echocardiography: Etiology of mitral regurgitation
 Primary:
 Secondary:
- Myxomatous
- Non-ischemic dilated CMP
- Endocarditis
- Ischemic heart disease
- Rheumatic
- HCM
- Trauma
- Congenital
- Drugs (ergotamines,
methysergide, pergolide, fen
fen)
Carpentier classification
 Type I = normal leaflet motion
but with annular dilatation or
leaflet perforation
 Type II = leaflet prolapse (eg
myxomatous disease) or
papillary muscle rupture
 Type III = restricted leaflet
motion.
IIIa = rheumatic disease
IIIb = ischemic or idiopathic
cardiomyopathy.
2D Echocardiography: additional information
 Left ventricular size and function and left
atrial size as clues to:
- severity of MR
- acuteness or chronicity
- necessity and timing of surgery
Mitral valve prolapse
 Occurs in 2.4% of the population (Freed at al. NEJM 1999)
 Patients exhibit fibromyxomatous changes in the mitral leafle
tissue that cause superior displacement of the leaflets into
the left atrium (by definition > 2 mm)
 The most common primary cause of isolated MR
requiring surgical repair
 Both familial (loci identified: chromosomes 11, 16, 13)
and “sporadic” cases observed
Mitral valve prolapse
Mitral valve prolapse
Mitral valve prolapse
 Leaflet elongation can manifest itself not only by
superior motion into the LA but also by anterior
motion that shifts the coaptation point toward the
aortic root and septum.
ANTERIOR
AO
AO
LV
Coaptation
SUPERIOR
Normal
MVP
II
I
RV
RV
AO
LV
AO
LV
AL
Coaptation
PL
AL
PL
LA
Coaptation
III
Prodromal form:
Nesta et al. Circulation 2005
Prodromal form

Anterior displacement of the coaptation point.

Mild bulging of the posterior leaflet relative to the
anterior.
Normal
Prodromal
Functional Mitral Regurgitation:
Incomplete Mitral Leaflet Closure
IMI or global LVD
NORMAL
Papillary
Muscle
Displacement
LV
Mitral Valve
Tethering
IMLC
LA
Courtesy of Judy Hung, MD
AO
MR
Functional Mitral regurgitation
Leaflet concavity (PS view) in functional MR
MR related to HOCM
• LV ejection through an LVOT narrowed by both septal
hypertrophy and anterior displacement of MV apparatus (PM
+ MV) causes the Venturi effect or “drag forces” which drag
the MV leaflets and chordae towards the septum
•
MR is related to SAM of the anterior mitral leaflet AND
failure of post leaflet to move anteriorly with consequent gap
between the two leaflets
Yu et al. Mitral regurgitation in hypertrophic cardiomyopathy: relationship
to obstruction and relief with myectomy. J Am Coll Cardiol 2000;36;2219-2225
Doppler Methods for assessment of severity
 Color flow Doppler
- Regurgitant jet area
- Vena contracta
- Flow convergence (PISA)
 Continuous wave Doppler
 Pulsed Doppler
- Mitral inflow pattern
- Quantitative parameters (regurgitant
volume, fraction, EROA)
Regurgitant jet area
 Pros:
- Simple, quick screen for mild or severe central MR
- Evaluates spatial orientation of jet
 Cons:
- Subject to technical, hemodynamic variation
- Underestimates severity in eccentric jets
 Mild: < 4 cm2 or < 20% of LA area
Moderate: variable
Severe: > 10 cm2 or > 40% of LA area
Vena contracta width
LAX
Mild: < 0.3 cm
Severe  0.7 with large central jet or with wall impinging jet of any size
SAX
Proximal isovelocity surface area (PISA)
 Based on the hydrodynamic principle that the flow profile
of blood approaching a circular orifice forms concentric,
hemispheric shells of increasing velocity and decreasing
surface area.
 Color flow mapping able to image one of these
hemispheres that corresponds to the aliasing velocity or
Nyquist limit of the instrument.
 The aliasing velocity should be adjusted to identify a flow
convergence region with a hemispheric shape.
 PkVreg = the peak velocity of the regurgitant jet by
continuous wave Doppler
 Reg volume = EROA x VTIreg jet
Proximal isovelocity surface area (PISA)
 Mild: EROA <0.2cm2
Severe: EROA >/=0.4cm2
 Pros:
- Presence of flow convergence at Nyquist limit of 50-60
cm/s alerts to significant MR
- Provides both lesion severity (EROA) and volume
overload (R Vol)
 Cons:
- Less accurate in eccentric jets
- Not valid in multiple jets
- Any error is determining the location/radius of the orifice
is squared
Example of PISA calculation
r = 0.8 cm
EROA = [6.28 x (.8)(.8) ml/s x 36] / [480 cm/s] = 0.3cm2
Supportive signs of MR severity
Other supportive signs of MR severity
 Mild MR:
- A-wave dominant mitral inflow **
- Normal LV size
 Severe MR:
- E-wave dominant mitral inflow (E > 1.2 m/s) **
- Enlarged LV and LA size
** Usually above 50 years or in conditions of impaired relaxation, in the absence
of mitral stenosis or other causes of elevated LA pressure
Quantitative pulsed Doppler parameters
ann
 In the absence of regurgitation, stroke volume should be
equal at different sites, e.g. the mitral and aortic annulus.
 In the presence of regurgitation (assuming the absence of
an intracardiac shunt), the flow through the affected valve
is larger than through other competent valves.
Supportive
signs of
severity parameters
Quantitative
pulsed
Doppler
Summary
JASE 2003;16:777
2D-TEE localization of MR defects
Probe in
Standard mid
esophageal
position
Foster et al. Ann Thorac Surg 1998;65:1025
2D-TEE localization of MR defects
Probe at 0
degrees,
effects of
flexion or
withdrawal
and
retroflexion or
advancement
Foster et al. Ann Thorac Surg 1998;65:1025
2D-TEE localization of MR defects
40 to 90 degrees,
effect of
clockwise and
counterclockise
probe rotation
Foster et al. Ann Thorac Surg 1998;65:1025
3D-TEE
 To simulate a surgeon’s view of the valve, the 3D
TEE image is positioned with the aortic valve the 11o’clock position.
Intra-Operative 2D and 3D TEE Depiction of MV
Prolapse and Leaflet Flail
3D-TEE quantitative analysis of the mitral apparatus
CMR
 Etiology of mitral regurgitation
 Quantitation of mitral regurgitation
 Better determination of volumes and LVEF (facilitating
surgical decision making in asymptomatic patients)
LVOT stack
LVOT
Therapy
Therapy
 The distinction between primary and secondary
MR is key
 Correction of primary MR in a timely fashion
reverses LV remodeling, PHTN, and heart failure
 It is less obvious that correcting secondary MR
will be curative or beneficial
Primary MR
 No conclusive data showing that medical therapy
(vasodilators or beta-blockers) is effective in primary MR
without heart failure (however recommended for heart failure)
 Surgical therapy
- Mitral valve repair instead of replacement is the preferred
method in non-rheumatic valves
Survival MV repair vs replacement
Carabello, B. A. J Am Coll Cardiol 2008;52:319-326
Copyright ©2008 American College of Cardiology Foundation. Restrictions may apply.
ACC/AHA 2006 guidelines
Secondary MR
 Should be treated with standard heart failure therapy
 In selected patients, CRT reduces amount of MR
 No evidence of improved survival with annuloplasty
 Also divergence of opinion about whether MR should be
corrected during revascularization
Results of Mitral Surgery in CHF
Carabello, B. A. J Am Coll Cardiol 2008;52:319-326
Copyright ©2008 American College of Cardiology Foundation. Restrictions may apply.
Limitations of ring annuloplasty
• Doesn’t address tethering
LV
• Further ventricular
remodeling after ring
Papillary
Muscle
Ischemic
LV
Tethering
Forces
LA
Ring
Annuloplasty
AO
Percutaneous therapies
Alfieri procedure
Percutaneous mitral
annuloplasty
Noninvasive assessment for percutaneous MVR
Role of TEE
Take home points
 Need to use multiple criteria for more accurate assessment
of MR
 Importance of distinguishing primary from secondary MR
 In secondary MR, indications for mitral valve intervention
are less certain and more data are needed
References
 Recommendations for evaluation of the severity of native valvular regurgitation
with 2D and Doppler echocardiography. J Am Soc Echocardiogr 2003;16
 O’Gara et al. The role of imaging in chronic degenerative mitral regurgitation.
JACC Cardiovascular Imaging 2008;1
 Carabello. The current therapy for mitral regurgitation. JACC 2008;52