Relief of mitral leaflet tethering following chronic myocardial infarction by chordal cutting diminishes left ventricular remodeling.
BACKGROUND
one of the key targets in treating mitral regurgitation (MR) is reducing the otherwise progressive left ventricular (LV) remodeling that exacerbates MR and conveys adverse prognosis. We have previously demonstrated that severing 2 second-order chordae to the anterior mitral leaflet relieves tethering and ischemic MR acutely. The purpose of this study was to test whether this technique reduces the progression of LV remodeling in the chronic ischemic MR setting.


RESULTS
a posterolateral MI was created in 18 sheep by obtuse marginal branch ligation. After chronic remodeling and MR development at 3 months, 6 sheep were randomized to sham surgery (control group) and 12 to second-order chordal cutting (6 each to anterior leaflet [AntL] and bileaflet [BiL] chordal cutting, techniques that are in clinical application). At baseline, chronic infarction (3 months), and follow-up at a mean of 6.6 months post-myocardial infarction (MI) (euthanasia), we measured LV end-diastolic (EDV) and end-systolic volume (ESV), ejection fraction, wall motion score index, and posterior leaflet (PL) restriction angle relative to the annulus by 2D and 3D echocardiography. All measurements were comparable among groups at baseline and chronic MI. At euthanasia, AntL and BiL chordal cutting limited the progressive remodeling seen in controls. LVESV increased relative to chronic MI by 109±8.7% in controls versus 30.5±6.1% with chordal cutting (P<0.01) (LVESV in controls, 82.5±2.6 mL; in AntL, 60.6±5.1 mL; in BiL, 61.8±4.1 mL). LVEDV increased by 63±2.0% in controls versus 26±5.5% and 22±3.4% with chordal cutting (P<0.01). LV ejection fraction and wall motion score index were not significantly different at follow-up among the chordal cutting and control groups. MR progressively increased to moderate in controls but decreased to trace-mild with AntL and BiL chordal cutting (MR vena contracta in controls, 5.9±1.1 mm; in AntL, 2.6±0.1 mm; in BiL, 1.7±0.1 mm; P<0.01). BiL chordal cutting provided greater PL mobility (decreased PL restriction angle to 54.2±5.0° versus 83±3.2° with AntL chordal cutting; P<0.01).


CONCLUSIONS
reduced leaflet tethering by chordal cutting in the chronic post-MI setting substantially decreases the progression of LV remodeling with sustained reduction of MR over a chronic follow-up. These benefits have the potential to improve clinical outcomes.
Messas
Emmanuel
E
Hôpital Européen Georges Pompidou, Department of Cardiology, University Paris Descartes, Paris. emmanuel.messas@egp.aphp.fr
Bel
Alain
A
Szymanski
Catherine
C
Cohen
Iris
I
Touchot
Bernard
B
Handschumacher
Mark D
MD
Desnos
Michel
M
Carpentier
Alain
A
Menasché
Philippe
P
Hagège
Albert A
AA
Levine
Robert A
RA
D000704:Analysis of Variance; D000818:Animals; D002815:Chordae Tendineae / Q000601:surgery*; D002908:Chronic Disease; D004195:Disease Models, Animal; D018450:Disease Progression; D015150:Echocardiography, Doppler / Q000379:methods; D019560:Echocardiography, Three-Dimensional / Q000379:methods; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000601:surgery; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D009203:Myocardial Infarction / Q000150:complications*; D012756:Sheep; D020257:Ventricular Remodeling
Circulation. 1989 Sep;80(3):589-98
2766511
Circulation. 1972 Aug;46(2):227-39
5046018
J Thorac Cardiovasc Surg. 2005 Aug;130(2):589-90
16077444
Circulation. 2007 Sep 11;116(11 Suppl):I259-63
17846314
Circulation. 2001 Oct 16;104(16):1958-63
11602501
Eur J Echocardiogr. 2004 Oct;5(5):326-34
15341868
Circulation. 2003 Sep 9;108 Suppl 1:II111-5
12970218
Circulation. 2007 Sep 11;116(11 Suppl):I288-93
17846319
Ann Thorac Surg. 1994 Feb;57(2):432-9
8311608
J Am Coll Cardiol. 1993 Mar 1;21(3):743-53
8436757
J Cardiol. 2004 Sep;44(3):113-7
15500161
J Am Soc Echocardiogr. 2003 Jul;16(7):777-802
12835667
J Thorac Cardiovasc Surg. 1984 Nov;88(5 Pt 1):718-25
6492840
J Thorac Cardiovasc Surg. 2000 Nov;120(5):966-75
11044323
Curr Opin Cardiol. 1999 Mar;14(2):104-10
10191968
J Am Soc Echocardiogr. 2003 Dec;16(12):1301-8
14652610
J Thorac Cardiovasc Surg. 2007 Jun;133(6):1483-92
17532944
Circulation. 1983 Sep;68(3 Pt 2):II76-82
6872199
Circulation. 1996 Nov 1;94(9 Suppl):II143-51
8901736
J Card Surg. 2008 Jan-Feb;23(1):52-7
18290888
J Am Soc Echocardiogr. 2005 Dec;18(12):1440-63
16376782
Circulation. 2000 Jun 13;101(23):2756-63
10851215
ASAIO Trans. 1990 Jul-Sep;36(3):M405-8
2252712
J Thorac Cardiovasc Surg. 2004 Dec;128(6):916-24
15573077
Circulation. 2004 Sep 14;110(11 Suppl 1):II115-22
15364849
Circulation. 1997 Sep 16;96(6):1826-34
9323068
Circulation. 1997 Aug 5;96(3):827-33
9264489
Circulation. 2001 Apr 3;103(13):1759-64
11282907
J Thorac Cardiovasc Surg. 1993 Mar;105(3):439-42; discussion 442-3
8445923
Circulation. 1986 Aug;74(2):306-14
3731421
J Thorac Cardiovasc Surg. 1983 Sep;86(3):323-37
6887954
Circulation. 2007 Feb 13;115(6):782-91
17283262
Circulation. 1992 Apr;85(4):1248-53
1555268
Circulation. 2005 Aug 30;112(9 Suppl):I396-401
16159853
Circulation. 1997 Sep 16;96(6):1999-2008
9323092
J Thorac Cardiovasc Surg. 2005 May;129(5):1173-4
15867798
Circulation. 2006 Jul 4;114(1 Suppl):I524-8
16820631
J Am Coll Cardiol. 2008 Jan 29;51(4):476-86
18222360
Am Heart J. 1992 Apr;123(4 Pt 1):961-6
1532283
Circulation. 1995 Feb 1;91(3):746-54
7828303
J Am Coll Cardiol. 1992 Apr;19(5):1101-5
1552101