Functional anatomy of the aortic root ΔΡΟΣΟΣ ΓΕΩΡΓΙΟΣ Διεσθσνηής Καρδιοθωρακοτειροσργικής Κλινικής Γ.Ν. «Γ. Παπανικολάοσ» Θεζζαλονίκη
What is the aortic root? represents the outflow tract from the LV provides the supporting structures for the leaflets of AV forms the bridge between LV and ascending aorta extends from the basal attachments of the leaflets within LV to the sinutubular junction
Aortic Root Anatomy Anatomic segment between LV and Asc Ao 1. Subcomissural triangles 2. Aortic annulus 3. Aortic cusps 4. Sinuses of Valsalva 5. Sinotubular Junction
Aortic cusps-sinuses 3 cusps 3 sinuses Left Right Non coronary
the triangle between the LC and NC aortic valvar sinuses is part of aortic-mitral fibrous continuity the triangle between NC and RC aortic valvar sinuses is directly continuous with the membranous part of the ventricular septum
Aortic annulus Fibrous structure The remnants of the removed leaflets? Virtual basal ring by joining together the most proximal parts of each leaflet
Sinotubular junction The STJ forms the discrete distal boundary of the root the length of the base is 1.5 times longer than the length of the free margin the diameter of the aortic annulus is 15 to 20% larger than the diameter of the sinotubular junction
The valvar leaflets are attached peripherally at this level, and the junction is an integral part of the valvar mechanism. Any significant dilation at the level of the sinotubular junction will produce valve incompetence
The three anatomic variations
The total length of the free margin: Equal to the circumference > to the intercommissural distance Complete opening in systole Wrinkle-free leaflet closure
Folding and unfolding of the free edge of the leaflets is necessary for opening and closure of the aortic valve Robicsek F et al. Ann Thorac Surg 2004; 77:177-185
Composition of aortic root Annulus collagen only at the nadir of leaflets attachment Sinuses elastic tissue ST junction elastic component but important collagen support Interleaflet triangles divide the sinuses and are exposed to ventricular pressure
Root deformation during the cardiac cycle: Isovolemic contraction - Expansion at the commissures Pull-and-release mechanism
Root deformation during the cardiac cycle: Ejection - Contraction at the annulus - Expansion at the commissures Root is more cylindrical to favor ejection
Root deformation during the cardiac cycle: Diastole - Re-expansion at the annulus - Contraction at the commissures Recoil to restore the static equilibrium
The paradoxes of the aortic valve The valve opens before the presence of forward flow Ejection continues even after the aortic pressure exceedes ventricular pressure The aortic valve already starts closing during ejection
Answer:
The paradoxes of the aortic valve The valve opens before the presence of forward flow Ejection continues even after the aortic pressure exceedes ventricular pressure The aortic valve already starts closing during ejection
Answer:
Mechanisms of leaflets closure: the role of the sinuses
In the absence of Valsalva sinuses
In the presence of Valsalva sinuses
The paradoxes of the aortic valve The valve opens before the presence of forward flow Ejection continues even after the aortic pressure exceeds ventricular pressure The aortic valve already starts closing during ejection
Answer:
Stress and aortic valve At 100 mmhg the aortic valve withstand a pressure of: 1,3 Kg vertically 0,6 Kg horizontally (200 g for each commissure) Elasticity is an important variable specially at sinus level
Stiffening of the aortic wall at the level of the sinuses leads to loss: the physiologic pull-and-release function of the aortic root stress overload on the aortic leaflets (eventually cusp fibrosis and calcification, and in some cases hemodynamically significant aortic valve disease)
Asc aorta aneurysm with STJ dilation and AI Supracoronary ascending aortic replacement
Noncoronary sinus dilated or altered by aortic dissection
Remodeling of the root was originally designed by M. Yacoub has been demonstrated to restore root geometry and improve aortic valve competence
Yacoub remodeling does not protect the annulus and leaves it susceptible to dilatation and valve insufficiency over time inappropriate for patients with Marfan syndrome or annuloaortic ectasia because the annulus may continue to dilate and cause aortic insufficiency
Yacoub Contraindications Calcification of aortic cusps AAA which starts at the level of STJ Patients>75y Patients with connective tissue disease who have a large annulus>30mm
T. David introduced the re-implantation operation Dacron graft is seated below the annulus of the aortic valve resulting in protection of both the valve leaflets and the annulus
YACOUB DAVID DAVID V The remodeling techniques exhibits valve dynamics closest to the native aortic root. In patients with reimplantation procedure, flow patterns and cusp motion are better with neo-aortic sinuses (DAVID V) than without. Aortic sinuses seem to decrease the mechanical stress on the aortic cusps, but it is not clinically apparent during the first decade of follow-up.
aortic valve-sparing operations are technically demanding operations only surgeons with extensive experience in aortic surgery should perform them the surgeon must have a sound knowledge of the anatomy and pathology of the aortic root and be able to apply the concepts of functional anatomy to create an anatomically and functionally satisfactory new aortic root TE David et al. J Thorac Cardiovasc Surg 2006;132:347-54 2010;140:14-19
ΦΕΙΡΟΥΡΓΕΙΑ ΚΑΡΔΙΑΣ ΚΑΙ ΑΟΡΤΗΣ ΚΑΤA ΤΑ ΕΤΗ 2010-2011-2012 9.2%
ΦΕΙΡΟΥΡΓΕΙΑ ΑΟΡΤΗΣ και ΘΝΗΤΟΤΗΤΑ 2010-2011-2012 32 36 21.9%
. Long-term survival after aortic valve-sparing operations was excellent in our patients. In fact, since valve-related events were infrequent and never fatal, survival in these patients was only slightly lower than that of the general population.