Pathophysiology of Mitral Valve Regurgitation

Pathophysiology of Mitral Valve Regurgitation

Pathophysiology of Mitral Valve
Regurgitation
Hartzell V. Schaff, MD
Division of Cardiovascular Surgery
Mayo Clinic, Rochester
©2013 MFMER | slide-1
No Disclosures
©2013 MFMER | slide-2
Thinking Volumetrically
How is it helpful?
• What is severe MR?
• What happens to EF after MV surgery?
• Is very poor LVEF a contraindication to
MV surgery?
• Difference in ischemic vs organic MR?
©2013 MFMER | slide-3
Thinking Volumetrically
How is it helpful?
• Understand multivalvular regurgitation
• Right ventricular volume overload with
TR and pulmonary valve regurg
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Pathophysiology of MR
Submitted to Circulation Dec, 2013
“The purpose of this investigation was to test the hypothesis
“Left
function,
as assessed
by LV
that ventricular
multiparametric
strain analysis
by magnetic
resonance
dimensions
ejection
(EF),early
wasLV
imaging andand
tissue
tagging fraction
could identify
within normal limits for all MR patients.”
dysfunction in minimally or asymptomatic patients, and that
the volume loading associated with MR creates a contractile
injury that is regionally and heterogeneously distributed in a
predictable pattern.”
©2013 MFMER | slide-5
Pathophysiology of MR
From a case report submitted Jan, 2014
“Transthoracic echocardiography showed an
isolated posterior mitral valve leaflet prolapse
leading to severe mitral regurgitation (effective
regurgitant orifice 57 mm2, regurgitant volume 63
ml/beat). The left ventricle was not dilated with a
preserved ejection fraction, and there was no
pulmonary hypertension.”
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Mitral Regurgitation
Qualitative Assessment
Grade 1
Grade 2
Grade 3
Grade 4
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Effective Regurgitant Orifice
Regurgitant flow rate
(6.28 x r2 x alias V)
=
ERO
Regurgitant Velocity
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Quantitative Hemodynamics
=
R volume
=
x
ERO
x
RTVI
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Mitral Regurgitation
Doppler Quantitation
V
A
TVI
Flow Rate = Area x Velocity
Volume = Area x ∫ Velocity (TVI)
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Mitral Regurgitation
Quantitative Hemodynamics
70 mL
50
mL
Systole
120 mL
Diastole
R volume = 120-70 = 50
R fraction = 50/120 = 42%
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Quantitation of Regurgitation
Concepts
Measures
Volume
overload
R volume
Measures
Effective
R orifice
Lesion
severity
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ERO of Organic MR
ASE Grading of Severity
Mild
Moderate
Severe
R volume (mL)
ERO (cm2)
<30
<0.20
30-59
0.20-0.39
≥60
≥0.40
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EF=60%
EDV=200
Regurg vol = 60
FW SV = 60
Total SV = 120
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LV Function After MV Repair
©2013 MFMER | slide-17
JTCVS April, 2002
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EF=50%
Regurg vol=80
FW SV=60
EDV=280
ESV=140
Total SV=140
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EDV=280
ESV=180
EF=36%
Total SV=100
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JTCVS Dec, 2010
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LV Function After Correction of MR
Intraoperative TEE before bypass and after
bypass + simultaneous hemodynamic data
• 25 patients undergoing MV repair
• 10 patients undergoing CABG
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LVED Dimension
8
MV repair
6
cm
4
2
0
Pre
Post
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Ejection Fraction
80
MV repair
70
%
P<0.001
60
50
40
Pre
Post
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Ejection Fraction
80
70
%
CABG
60
50
40
Pre
Post
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LV Forward SV
80
MV repair
70
mL
60
50
40
Pre
Post
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LV Forward SV
80
70
CABG
mL
60
50
40
Pre
Post
©2013 MFMER | slide-27
LV Function Early After Correction of MR
• EF decreases primarily due to increase of
end-systolic dimension of LV
• Compensatory mechanism to prevent
augmentation of LV stroke volume
©2013 MFMER | slide-28
JTCVS May, 2009
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EF Improves Over Time
68
64
60
EF
56
52
48
P<0.001
44
40
Preop
Pre DC
<1 yr
1-3 yr
3-5 yr
Time
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Recurrent MV Disease
• 77 yr female s/p MV repair 2002
• Heart murmur and 2 episodes of endocarditis and AF
• Severe MR by echo with ERO 0.5 cm2, RVol 88 ml,
LVEDD 51 mm with ant leaflet prolapse
• MV repair with post annuloplasty band and 4
neochordae to ant leaflet
• Discharge echo - No MR, normal LV size and function
LVEF 55-60%
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Recurrent MR
• Atrial fib with rapid HR – cardioversion  AV node
ablation with PPM (5/2013)
• Colon cancer – ileostomy + chemotherapy 2007
• Scoliosis – worsening over time
• Hypothyroid – on Synthroid – recent ↑ dose
• Esophageal spasm – treated with diltiazem and
dilatations
• Profound fatigue and DOE
©2013 MFMER | slide-32
“My best recommendation would be for her to have a redo
sternotomy with mitral valve replacement with a bioprosthesis,
tricuspid annuloplasty and MAZE procedure. She could have an
implantation of a right atrial lead postoperatively and have her
return to sinus rhythm if possible.
I have called Dr. Schaff and explained the current situation and
what my thoughts are, and he will be evaluating her.”
©2013 MFMER | slide-33
Outside echo
Recurrent MR
• Severe LA enlargement
• Moderately severe MR
• Moderate TR
• LV?
Repeat echo Mayo
• RV>30 ml
• MV gradient 8 mmHg
• EF 60%
• LVEDD 45 mm
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Mild MR
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Mitral Regurgitation EF≤30%
Event-Free Survival
100
80
No MV annuloplasty
60
%
40
MV annuloplasty
20
0
0
500
1000
Days
1500
2000
Wu et al: JACC, 2005
©2013 MFMER | slide-38
Ischemic Cardiomyopathy
No Mitral Regurgitation
EF 25%
SV 50 cc
LVEDV 200 cc
©2013 MFMER | slide-39
Inferior MI
LV enlarged
Local remodeling
MR present
LVEDV ?
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Ischemic Cardiomyopathy
Mitral Regurgitation
EF 25%
SV 50 cc
Regurg vol 60 cc
Total SV 110
LVEDV
440 cc
©2013 MFMER | slide-41
Thinking Volumetrically
Key Points
• It has to add up!
• Multiple moderate regurgitant lesions produce
severe overload
• Early after correction of MR (or AR or TR) EF
declines – compensatory
• Recovery of EF depends on  LV volume
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Questions & Discussion
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