Document Detail

Saddle-shaped mitral valve annuloplasty rings experience lower forces compared with flat rings.
MedLine Citation:
PMID:  18824763     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: New insight into the 3D dynamic behavior of the mitral valve has prompted a reevaluation of annuloplasty ring designs. Force balance analysis indicates correlation between annulus forces and stresses in leaflets and chords. Improving this stress distribution can intuitively enhance the durability of mitral valve repair. We tested the hypothesis that saddle-shaped annuloplasty rings have superior uniform systolic force distribution compared with a nonuniform force distribution in flat annuloplasty rings. METHODS AND RESULTS: Sixteen 80-kg pigs had a flat (n=8) or saddle-shaped (n=8) mitral annuloplasty ring implanted. Mitral annulus 3D dynamic geometry was obtained with sonomicrometry before ring insertion. Strain gauges mounted on dedicated D-shaped rigid flat and saddle-shaped annuloplasty rings provided the intraoperative force distribution perpendicular to the annular plane. Average systolic annular height to commissural width ratio before ring implantation was 14.0%+/-1.6%. After flat and saddle shaped ring implantation, the annulus was fixed in the diastolic (9.0%+/-1.0%) and systolic (14.3%+/-1.3%) configuration, respectively (P<0.01). Force accumulation was seen from the anterior (0.72N+/-0.14N) and commissural annular segments (average 1.38N+/-0.27N) of the flat rings. In these segments, the difference between the 2 types of rings was statistically significant (P<0.05). The saddle-shaped annuloplasty rings did not experience forces statistically significantly larger than zero in any annular segments. CONCLUSIONS: Saddle-shaped annuloplasty rings provide superior uniform annular force distribution compared to flat rings and appear to represent a configuration that minimizes out-of-plane forces that could potentially be transmitted to leaflets and chords. This may have important implications for annuloplasty ring selections.
Morten O Jensen; Henrik Jensen; Morten Smerup; Robert A Levine; Ajit P Yoganathan; Hans Nygaard; J Michael Hasenkam; Sten L Nielsen
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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:  118     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-09-30     Completed Date:  2008-10-23     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  S250-5     Citation Subset:  AIM; IM    
Department of Cardiothoracic & Vascular Surgery, Aarhus University Hospital, Skejby, 8200 Aarhus N, Denmark.
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MeSH Terms
Coronary Circulation
Equipment Design
Mitral Valve / surgery*
Postoperative Period
Prostheses and Implants* / standards
Stress, Mechanical
Ventricular Function, Left
Grant Support

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

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