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(Circulation. 2002;106:I-27.)
© 2002 American Heart Association, Inc.

Surgery for Valvular Heart Disease

Annular Versus Subvalvular Approaches to Acute Ischemic Mitral Regurgitation

Tomasz A. Timek, MD; David T. Lai, FRACS; Frederick Tibayan, MD; David Liang, MD, PhD; Filiberto Rodriguez, MD; George T. Daughters, MS; Paul Dagum, MD, PhD; Neil B. Ingels, Jr, PhD; Craig Miller, MD

From the Department of Cardiovascular and Thoracic Surgery (T.A.T., D.T.L., F.T., F.R., G.T.D., P.D., N.B.I, C.M.), and ^bDivision of Cardiovascular Medicine (D.L.), Stanford University School of Medicine, Stanford, Calif.; and ^cLaboratory of Cardiovascular Physiology and Biophysics, Research Institute of the Palo Alto Medical Foundation, Palo Alto, Calif. (G.T.D., N.B.I.).

Correspondence to D. Craig Miller, MD, Department of Cardiovascular Surgery, Falk Cardiovascular Research Center, Stanford University School of Medicine, Stanford, CA 94305-5247. E-mail dcm{at}stanford.edu

Background Ischemic mitral regurgitation (IMR) has been attributed to annular dilatation, papillary muscle (PM) displacement ("apical leaflet tenting"), or both. We compared the efficacy of reducing annular or subvalvular dimensions to gain more mechanistic insight into acute IMR.

Methods Eight adult sheep underwent implantation of radiopaque markers on the LV, mitral annulus (MA), each leaflet edge, and each PM tip. Trans-annular septal-lateral (SL) and inter-PM tip sutures were placed and externalized. Biplane videofluoroscopy and transesophageal echocardiography were performed before and continuously during LCx occlusion-induced IMR with SL annular (SLAC) or inter-PM (PAPS) suture tightening (4 to 5 mm of cinching for 5 seconds during ischemia). MA SL dimension, inter-papillary distance (APM-PPM), and the distances between the anterior (APM) and posterior (PPM) PM tips and the mid-septal annulus ("saddle horn") were calculated from 3-D marker coordinates at end-systole.

Results SLAC reduced IMR (grade=2.1±0.6 versus 0.7±0.5, P.001), SL annular diameter (4.9±2.5 mm smaller versus pre-cinching; P.001), and PM-"saddle horn" distances (0.9±0.7 and 1.0±0.8 mm reduction for APM and PPM, respectively; P.005). PAPS reduced APM-PPM distance (3.7±1.8 mm reduction versus precinching; P.001), only slightly decreased the PPM-"saddle horn" distance (0.3±0.3 mm reduction; P.03), and had no effect on IMR.

Conclusions Acute IMR was abolished by annular SL reduction, which also repositioned both PM tips closer to the mid-septal annulus and paradoxically increased leaflet "apical tenting"; reducing inter-papillary dimension was not effective, even though it displaced the leaflets toward the annular plane (less "apical tenting").

Key Words: ischemic mitral regurgitation • coronary artery disease • mitral regurgitation • mitral annulus • annular cinching