Page 1
Intraoperative TEE Evaluation of Ischemic/Functional Mitral Regurgitation
Stanton Shernan, MD, FAHA, FASE
Professor of Anaesthesia
President, National Board of Echocardiography
Director of Cardiac Anesthesia
Brigham and Women’s Hospital
Department of Anesthesiology, Perioperative and Pain Medicine
Harvard Medical School
While structural, degenerative disease of the mitral valve remains the most common
etiology of surgically treated mitral regurgitation (MR) in the US, patients with functional MR
due to ischemia or global left remodeling remains an important cardiac surgical population.
Ischemic mitral regurgitation (IMR) is defined as mitral valve (MV) incompetence that occurs
directly as a result of coronary artery disease (CAD), and not an intrinsic pathological process.
Mechanisms for the development of IMR are dynamic, complex and multifactorial (1).
Hypokinesia of left ventricle (LV) segments at the base of the papillary muscle may be more
responsible than papillary muscle dysfunction alone for causing retraction of MV leaflets toward
the apex and subsequent incomplete leaflet coaptation. Asymmetric MV annular dilatation can
also interfere with normal leaflet coaptation and cause IMR. Furthermore, increased LV
sphericity has been associated with IMR due to incomplete mitral leaflet coaptation assessed as
an increased tenting area between the MV leaflets and annulus.
A comprehensive pre-cardiopulmonary bypass (CPB) echocardiographic interrogation of
IMR begins with a thorough two-dimensional (2D) evaluation to discern the specific mechanism.
The degree of leaflet motion restriction, annular dimensions, distance between leaflet coaptation
points and septum, anterior and posterior leaflet heights, assessment of regional and global LV
function, and localization of regurgitant jet and severity of MV incompetence should all be
assessed. In addition, any echocardiographically identifiable risk factors for repair failure should
also be identified (2-4). Further delineation of MV pathology and mechanisms associated with
IMR may be obtained using 3-D reconstruction or real-time 3D echocardiography (5-10). The
Page 2
pre-CPB intraoperative echocardiographic evaluation of IMR must take into consideration the
effect of general anesthesia and positive pressure ventilation on the severity of MV incompetence.
Other hemodynamic factors including alterations in preload, acute myocardial ischemia, as well
as heart rate and rhythm may also be responsible for the dynamic nature of IMR. Ideally, efforts
should be made to optimize myocardial performance by administering volume, vasconstrictors,
inotropes or even dobutamine stress echocardiography, before a definitive diagnosis which can
impact surgical decision-making, can be ascertained (11-13).
The initial post-CPB TEE exam is essential in helping to determine MV competency, and
begins with an understanding of the surgical procedure that was performed. The almost
universally reported benefits of MV repair using an undersized annuloplasty ring support the
utility of this technique in the vast majority of patients with IMR. Percutaneous transvenous
annuloplasty devices placed in the coronary sinus have also been utilized to reduce the anteriorposterior mitral annulus dimension, improve leaflet co-aptation and reduce IMR severity (14).
Furthermore, novel surgical approaches including external LV remodeling by infarct plication
(15), external repositioning of the papillary muscles (16), basal chordal cutting (17), and the use
of three-dimensional, asymmetrically shaped geometric annular rings (18) have been proposed as
potentially more effective strategies to treat IMR.
While acute MR present in the immediate post-CPB period may be associated with
perivalvular leaks or residual leaflet malcoaptation, the mechanism of recurrent and persistent
functional IMR in the chronic phase after surgical annuloplasty may be due to augmented and
progressive posterior leaflet tethering (19); anterior leaflet tethering (20), continued left
ventricular remodeling (21), as well as other mechanisms. Significant mitral stenosis following
MV repair surgery is much less common than persistent MR, and can be more challenging to
diagnose. (23-25)
Page 3
References
1. Levine RA.Circ.2005;112:745-58
2. Ayanwu A. JASE 2009;22:1265-1268
3. Penicka M. Circ 2009;120:1474-1481
4. Kongsaerepong V.. AJC 2006;98:504-508
5. Abraham T.AJC 1997; 80:1577-1582
6. Jassar A. ATS 2011;91:165-171
7. Vergnat M. ATS 2011; 157-64
8. Watanabe JASE 2006;19:71-75
9. Watanabe. Circ 2005;112:I-458
10. Mahmood F. ATS 2010;90:1212-1220
11. Shiran A. JASE 2007;6:690-7
12. Matyal R. JCVA 2009 ;4 :555-557
13. Banks D. JCVA 2009;4:558-560
14. Webb JG.Circ. 2006;113:851-55
15. Liel-Cohen N, Circ 2000; 101:2756-27636
16. Hung J. Circ 2002; 106:2594-26007
17. Messas E. Circ 2001;104:1958-19638
18. Votta E. ATS 2007;84:92-1019
19. Kuwahara E. Circ 2006;114 (Suppl I):I529-34
20. Lee A. Circ 2009;119:2606-2614
21. Magne J. JASE 2009;22:1256-1564
22. Maslow A, J Cardiothorac Vasc Anesth 2011;25:221-228
23. Poh K. Int J Cardiol 2006;108:177-180,
24. Riegel A, PLOS One 2011;6:e26559