Document Detail

Persistent reduction of ischemic mitral regurgitation by papillary muscle repositioning: structural stabilization of the papillary muscle-ventricular wall complex.
MedLine Citation:
PMID:  17846314     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Recurrent ischemic mitral regurgitation (IMR) is frequent despite initial reduction by annuloplasty because continued LV remodeling increases tethering to the infarcted papillary muscle (PM). We have previously shown that PM repositioning by an external patch device can acutely reduce IMR. In this study, we tested the hypothesis that IMR reduction persists despite possible continued LV remodeling. METHODS AND RESULTS: In 7 sheep, we used a chronic ischemic posterior infarct model that produces LV dilatation and MR over 10 weeks. An epicardial patch device was adjusted under echo guidance to reduce MR, with follow-up over a further 8 weeks and evaluation by 3D echo and sonomicrometry. In all 7 sheep, moderate IMR resolved with acute patch application and PM repositioning (6.5+/-1.8 mm to 0.6+/-1.3 mm proximal jet width, P<0.001) without decrease in LVEF (43+/-3% to 44+/-8%). Eight weeks after PM repositioning, MR was not significantly greater (0.6+/-1.3 mm versus 1.0+/-1.0 mm, P=NS) despite an increase in LV volumes in 3 animals (2 had increases of 50+/-15%). On average, LV volumes did not change significantly (ESV: 46+/-8 mL versus 49+/-15 mL; P=NS and EDV: 85+/-16 mL versus 89+/-30 mL; P=NS). LVEF was unchanged from acute to chronic patch (44+/-8% versus 43+/-8%). Contractility as end-systolic elastance did not decrease from the chronic MI to the acute and chronic patch stages, nor were there any significant changes in dP/dt, LV stiffness constant, or time constant of LV relaxation (Tau). CONCLUSION: PM repositioning is persistently effective in reducing moderate chronic IMR, even when LV volume increases. This may reflect structural stabilization by an external patch device of the papillary muscle-LV wall complex that controls mitral valve tethering.
Judy Hung; Miguel Chaput; J Luis Guerrero; Mark D Handschumacher; Lampros Papakostas; Suzanne Sullivan; Jorge Solis; Robert A Levine
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Circulation     Volume:  116     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-09-11     Completed Date:  2007-10-11     Revised Date:  2007-12-03    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  I259-63     Citation Subset:  AIM; IM    
Massachusetts General Hospital, Cardiac Ultrasound Laboratory, Blake 256, 55 Fruit Street, Boston, MA 02114, USA.
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MeSH Terms
Cardiac Surgical Procedures / methods*
Mitral Valve Insufficiency / radiography,  surgery*
Myocardial Ischemia / radiography,  surgery*
Papillary Muscles / radiography,  surgery*
Ventricular Dysfunction, Left / radiography,  surgery*
Grant Support
NHLBI R01 038176//PHS HHS; R21 EB005294/EB/NIBIB NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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