1. Mitral Regurgitation
Francesca N. Delling, MD
July 8, 2009

2. Outline Anatomy Diagnosis
- Two-dimensional echocardiography (etiology)
- Doppler methods (assessment of severity)
- Role of 2D and 3D-TEE
- Role of CMR
Treatment

3. Anatomy: The mitral valve apparatus
Subvalvular apparatus (papillary muscles with their supporting left ventricular walls and chordae tendineae)
Mitral annulus
Mitral valve leaflets

4. Anatomy: The mitral valve
Reference view from the left ventricular apex
Surgical view from the left atrium with the heart rotated

5. Diagnosis

6. 2D Echocardiography: Etiology of mitral regurgitation
Primary:
- Myxomatous
- Endocarditis
- Rheumatic
- Trauma
- Congenital
- Drugs (ergotamines,
methysergide, pergolide, fen fen)
Secondary:
- Non-ischemic dilated CMP
- Ischemic heart disease
- HCM

7. 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.

8. 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

9. Mitral valve prolapse
Occurs in 2.4% of the population (Freed at al. NEJM 1999)
Patients exhibit fibromyxomatous changes in the mitral leaflet
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

10. Mitral valve prolapse

11. Mitral valve prolapse

12. 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
Septum
Septum AO AO
Chromosome 13 study: while phenotyping family members we observed that….This has led to the identification of a “prodromal form” or form fruste LV A A
Coaptation P
SUPERIOR
Normal
MVP 3

13. Nesta et al. Circulation 2005
Interestingly, these individuals were all carriers of the locus
Nesta et al. Circulation 2005

14. Prodromal form Anterior displacement of the coaptation point.
Mild bulging of the posterior leaflet relative to the anterior.
Normal
Prodromal

15. Functional Mitral Regurgitation: Incomplete Mitral Leaflet Closure
IMI or global LVD
NORMAL MR
Papillary Muscle Displacement
Mitral Valve
Tethering
IMLC LV
Fig 2. Left panel depicts normal mitral valve geometry. Right panel shows restricted leaflet closure termed incomplete mitral leaflet closure. Several mechanisms have been proposed, including abnormal tethering of the mitral valve by displacement of the papillary muscles in the ischemic territory and by annular dilatation. LA AO
Courtesy of Judy Hung, MD 3

16. Functional Mitral regurgitation

18. Leaflet concavity (PS view) in functional MR

21. 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

22. Yu et al. Mitral regurgitation in hypertrophic cardiomyopathy: relationship
to obstruction and relief with myectomy. J Am Coll Cardiol 2000;36;

23. 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)

24. 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
Small central jet
Large central jet or variable size wall-impinging jet

25. Vena contracta width SAX LAX Mild: < 0.3 cm
Narrowest portion of a jet that occurs at or just downstream from the orifice. The examiner must search in multiple planes perpendicular to the commissural line (such as the PLA view). Widths are not additive, but their cross sectional areas (in SAX view) are
Mild: < 0.3 cm
Severe  0.7 with large central jet or with wall impinging jet of any size

26. 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.

27. Reg volume = EROA x VTIreg jet
PkVreg = the peak velocity of the regurgitant jet by continuous wave Doppler
Reg volume = EROA x VTIreg jet
The radius of the hemisphere is then measured…
The regurgitant volume can be estimated as EROA multiplied by the velocitiy time integral of the regurgitant jet
Since PISA calculation provides an instantaneous peak flow rate, EROA is the maximal EROA

28. Proximal isovelocity surface area (PISA)
Mild: EROA <0.2cm2
Severe: EROA >/=0.4cm2
Pros:
- Presence of flow convergence at Nyquist limit of 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
Therefore PISA is more accurate if the aliasing velocity can be adjusted to obtain a radius of >/=1cm.

29. Example of PISA calculation
r = 0.8 cm
Radius is 0.8, the color Doppler scale has been shifted down so that the MR aliasing velocity has been reduced to 36 cm/s, thus maximizing resolution for measuring the aliasing radius
EROA = [6.28 x (.8)(.8) ml/s x 36] / [480 cm/s] = 0.3cm2

30. Supportive signs of MR severity
Example of findings of continuous wave (CW) Doppler recordings and pulmonary vein flow by
pulsed Doppler in a case with mild and another with severe mitral regurgitation (MR). In mild MR,
spectral recording of the jet has a soft density with a parabolic, rounded contour of the regurgitant velocity
whereas in severe MR, the jet is dense with a triangular, early peaking of the velocity (arrow). Pulmonary
vein flow is normal in mild MR with predominance of systolic flow (S). In contrast, the case with severe
MR displays systolic flow reversal. D, Diastolic flow velocity.

31. 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
Greater E because of increased diastolic flow

32. 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.
Stroke volume = product of CSA and the velocity time integral of flow at the annulus

33. Quantitative pulsed Doppler parameters
Supportive signs of severity
Need to add pros/cons of CW, PW and pulm vein
CW jet profile
Pros: simple, readily available
Cons: qualitative
PW peak mitral E velocity
Pros simple, readily available, A wave dominance excludes severe MR (severe MR = increased diastolic flow across the mitral valve = increased E velocity)
Cons: influenced by LA pressure, LV relaxation, MV area, and atrial fibrillation
Quantitative Pw
Cons: measurement of flow at the MV annulus less reliable in calcific MV. Not valid with concomitant significant AR unless pulmonic site is used
Pulm veins
Pros: simple
Cpms: influenced by LA pressure, afib.

34. Summary
JASE 2003;16:777

35. 2D-TEE localization of MR defects
Probe in
Standard mid
esophageal position
Tee provides a systematic method to accurately localize MR defects and improves preoperative assessment
Foster et al. Ann Thorac Surg 1998;65:1025

36. 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

37. 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

38. 3D-TEE
To simulate a surgeon’s view of the valve, the 3D TEE image is positioned with the aortic valve the 11-o’clock position.

39. Intra-Operative 2D and 3D TEE Depiction of MV Prolapse and Leaflet Flail
Schematic (upper row) and 2D as well as 3D echocardiographic examples of a patient with a normal mitral valve (left panels), mitral
valve prolapse (P1, middle panels) and a flail mitral valve (P2, right panels) as visualized with 2D TEE (long-axis mid esophageal TEE
views (middle row) and real-time 3D TEE volume rendering from the left atrial perspective (bottom row). The surgical views obtained
with real-time 3D TEE provide unique visualization and better understanding of the anatomic relationships of the mitral valve annulus,
commissures and leaflets. Abbreviations as in Figures 1 and 2.

41. 3D-TEE quantitative analysis of the mitral apparatus
Examples of 3D renderings of the mitral valve obtained from 3D-TEE dataset using software designed for quantitative analysis of the
mitral apparatus. (Top, Left) Antero-posterior diameter is shown in green. (Top, Right) Annular height. (Bottom Left) Anterior mitral leaflet
surface area (hatched) with posterior middle scallop leaflet prolapse. (Bottom, Right) Angle between the mitral and aortic annuli. A
anterior, P posterior, AL anterolateral, PM posteromedial, Ao aorta, TEE transesophageal echocardiography.

42. CMR Etiology of mitral regurgitation
Quantitation of mitral regurgitation
Better determination of volumes and LVEF (facilitating
surgical decision making in asymptomatic patients)

43. LVOT stack
A) Left ventricular outflow tract (LVOT) stack prescription is created by obtaining parallel slices across the mitral valve perpendicular to the long axis of the valve.

44. LVOT Borderline-severe MR Eccentric anteriorly-directed flow jet
MVP of P2 scallop with flail posterior leaflet
Mildly enlarged LV with NL systolic function
LVEF was normal at 68%
Effective forward LVEF moderately at 35%
LV Stroke volume 145 ml
Mitral Valve regurgitant volume 70 ml
Normal RV cavity size and systolic function
RVEF normal at 53%
Mild RAE. Mild-to-moderate LAE.

45. Therapy

46. 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

47. 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

48. Survival MV repair vs replacement
Survival after mitral valve repair (MVP) is compared with MVR for propensity-matched groups
Carabello, B. A. J Am Coll Cardiol 2008;52:
Copyright ©2008 American College of Cardiology Foundation. Restrictions may apply.

49. ACC/AHA 2006 guidelines

50. 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

51. Results of Mitral Surgery in CHF
Unadjusted (A) and propensity-adjusted (B) survival of patients with secondary MR are shown and separated into groups of CABG alone or CABG plus annuloplasty. No difference in survival was detected
Carabello, B. A. J Am Coll Cardiol 2008;52:
Copyright ©2008 American College of Cardiology Foundation. Restrictions may apply.

52. Limitations of ring annuloplastyAO LA LV
Papillary Muscle
Tethering
Forces
Ring Annuloplasty
Ischemic
Doesn’t address tethering
Further ventricular remodeling after ring

53. Percutaneous therapies
Alfieri procedure
Schematic of edge-to-edge MV repair (Alfieri procedure; (top) and percutaneous
mitral annuloplasty (bottom), capitalizing on the relationship
between the coronary sinus and the annulus.
Percutaneous mitral
annuloplasty

54. Noninvasive assessment for percutaneous MVR
Role of TEE

55. 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

56. 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