Document Detail

Effect of chronotropy and inotropy on stitch tension in the edge-to-edge mitral repair.
MedLine Citation:
PMID:  17846317     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Our prior studies suggest that mitral annular septal-lateral (SL) diameter is the chief determinant of "Alfieri stitch" tension, but hemodynamic parameters may also play a role. We approximated the central edge of the mitral leaflets with a miniature force transducer to measure tension (T) at the leaflet approximation point during inotropic and chronotropic stimulation. METHODS AND RESULTS: Eight sheep were studied under open-chest conditions immediately after surgical placement of a miniature force transducer to approximate the leaflets and implantation of radiopaque markers on the LV and mitral annulus (MA). Chronotropic stimulation was induced with atrial pacing at 130 minutes(-1) (n=5) whereas inotropic state was increased with i.v. CaCl2 bolus (n=8). Hemodynamic data, stitch tension, and 3-D marker coordinates were obtained throughout the cardiac cycle before and during each intervention. Peak stitch tension (T(MAX)) under all conditions was observed in diastole and temporally correlated with peak annular SL (SL(MAX)) size. Atrial pacing did not change peak transducer tension or annular size. Calcium infusion also did not alter peak transducer tension (0.29+/-0.11 versus 0.32+/-0.10 N; P=NS) and only slightly reduced SL dimension (29.9+/-3.3 versus 29.3+/-3.5 mm; P<0.05). CONCLUSION: Isolated increase in heart rate or inotropic state did not alter peak stitch tension whereas enhanced contractile state decreased SL diameter minimally. These data, combined with those from our previous study, suggest that geometric (SL diameter) rather than hemodynamic parameters are the main determinants of "Alfieri stitch" tension. This implies that any interventional or surgical edge-to-edge repair performed without concomitant annular reduction to limit the SL dimension could expose the leaflet junction to forces which could limit repair durability.
Tomasz A Timek; Sten L Nielsen; David T Lai; David Liang; George T Daughters; Neil B Ingels; D Craig Miller
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Publication Detail:
Type:  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:  2008-08-13    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  I276-81     Citation Subset:  AIM; IM    
Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, California 94305-5247, USA.
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MeSH Terms
Heart Rate / physiology*
Heart Valve Prosthesis Implantation / instrumentation,  methods*
Mitral Valve / physiology*,  surgery*
Mitral Valve Insufficiency / physiopathology,  surgery
Myocardial Contraction / physiology*
Surface Tension
Suture Techniques* / instrumentation
Grant Support
Comment In:
Circulation. 2008 Jul 22;118(4):e78; author reply e79   [PMID:  18645061 ]

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

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