Ανατομία και Φυσιολογία Μιτροειδούς Βαλβίδας σε υγιείς

Transcription

1 Ανατομία και Φυσιολογία Μιτροειδούς Βαλβίδας σε υγιείς Βλάσης Νινιός MD, MRCP Κλινική Άγιος Λουκάς Θεσσαλονίκη Tuesday, March 10, 15

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3 Components of Mitral Valve Mitral annulus Chordae tendineae Papillary muscles Mitral leaflets Tuesday, March 10, 15

4 Mitral annulus

5 Mitral annulus Thin, nonconductive, fibrofatty membrane Hyperbolic paraboloid Nonplanar shape reduces the mechanical stress exerted on the valve leaflets Three types of motion: sphincteric contraction translation folding Sphincteric contraction reduces annular area by approximately 25% Am Heart J 2009;158: Circulation 2002; 106:711-7 JASE 2000;13: Tuesday, March 10, 15

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17 Chordae tendineae

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25 Chordae tendineae The human heart contains >100 chords arising from about 25 major chordal trunks The strut chords, like a stretched rubber band, are under continuous tension, which is transmitted to the PMs and fibrous trigones The aortomitral angle is suspended by the tension in the strut chords, which pull on the fibrous trigones Am Heart J 2009;158: Circulation 2003;108: Thorac Cardiovasc Surg 2003;51:190-5 Tuesday, March 10, 15

26 Strut cords

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29 Papillary muscles

30 Papillary muscles The contraction of the PMs is coordinated with that of the LV as a whole Contraction of helically arranged muscle fibers results in torsional motion around the major axis of the LV The PMs also have a rotational motion around the long axis of the LV Am Heart J 2009;158: Eur J Cardiothorac Surg 2007;32: Tuesday, March 10, 15

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32 Mitral leaflets

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34 Mitral leaflets The mitral valve is metabolically active synthesizing contractile proteins, collagen, elastin, and proteoglycan Valve tissue undergoes remodeling in response to the hemodynamic insults The zone of coaptation measures approximately 1 cm in height Am Heart J 2009;158: Circulation 2008;118(Suppl 1):S243-9 Tuesday, March 10, 15

35 Mitral leaflets During systole, the mitral valve leaflets billow toward the left atrium This curvature reduces leaflet stress acting synergistically with the nonplanarity of the annulus The anterior mitral leaflet undergoes dynamic changes in surface contour throughout the cardiac cycle Am Heart J 2009;158: Circulation 2003;107: J Heart Valve Dis 2008;17:54-61 Tuesday, March 10, 15

36 Surgical anatomy of the heart. New York: Cambdridge University Press; p. 55

37 Mitral leaflets Myocytes occupying the basal portion of the mitral leaflets are activated immediately after the left atrium and may play a role in valve closure Like annular contraction, valvular contraction may position the leaflets prior to ventricular systole Valvular contraction may work in tandem with PM contraction to limit the atrial displacement of the leaflets during ventricular systole Am Heart J 2009;158: Cardiovasc Res 1978;12: Am J Physiol 1992;31:H56-62 Tuesday, March 10, 15

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43 Functional classification

44 Type I

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51 Type II

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63 Mitral annular disjunction in Mitral valve prolapse Tuesday, March 10, 15

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65 Type IIIa

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69 Type IIIb

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83 IMR PRE

84 IMR PRE

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99 POST PRE Tuesday, March 10, 15

100 ΑΝΑΔΙΑΜΟΡΦΩΣΗ ΓΛΩΧΙΝΩΝ LEAFLETS PRE POST ANTERIOR AREA 1235 mm sq. 762 mm sq. POSTERIOR AREA 702 mm sq. 549 mm sq. TENTING VOLUME 6.8 ml 4.7 ml LENGTH A mm 25.1 mm LENGTH P mm 17.8 mm TENTING HEIGHT 13.2 mm 10.4mm Tuesday, March 10, 15

101 ΑΝΑΔΙΑΜΟΡΦΩΣΗ ANNULUS PRE POST AL 45.3 (mm) 34.5 (mm) AP 38.3 (mm) 32.9 (mm) PERIMETER 145 (mm) 116 (mm) AREA 1542 (mm sq.) 945 (mm sq.) Tuesday, March 10, 15

102 CONCLUSIONS Functional anatomy of the Mitral valve is a complex dynamic interaction of several anatomic substructures Each one plays significant role in maintaining the integrity of the MV apparatus Disease process is heterogeneous and affects the function in multiple ways hence the need for functional clacification Recent advances in imaging (3D ECHO) have allowed better understanding of the alterations of the MV structures and have aided diagnosis and Tuesday, March 10, 15