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1、Bicuspid Aortic Valve DiseaseNew Insights in Pathogenesis 106(8):900-4Etiology and Development of Congenital BAV1. Abnormal aortic cusp formation.2. Adjacent cusps fail to separate, resulting in a single aberrant cusp. 3. Phenotypic continuum (unicuspid, bicuspid, tricuspid)Fedak P, Verma S, Circula
2、tion 2002; 106(8):900-4 Fedak, David, Borger, Verma, Expert Rev Cardiovasc Ther 2005Bicuspid Aortic Valve (BAV) MorphologySabet et al, Mayo Clin Proc, 1994;74:14-26Leaflet PositionAnterior-PosteriorLeft-RightEtiology and MechanismsnAbnormal blood flow through aortic valve during valvulogenesis resul
3、ts in a failure of cusp seperationnEmbryonic theory (abnormalities in conotruncal seperation)nCono-truncus divided by the spiral conotruncal septum nRight 126(3): 797-806 - 50% of young asymptomatic patients- Independent of valve function- Associated degeneration of aortic media- Etiology and mechan
4、isms unknown Aortic Dilatation and BAV Aortic Dilatation and BAV Poor Correlation Between Degree of AS and Aortic DilationMagrad et al. JTCVS 2001MediaIntimaAdventitiaHuman AortaElastic Lamellae of Media Elastin 96: 3891 Fibrillin-1 Deficient Mouse: Progressive Aortic Dilation Verma S, Circ Res 2001
5、; 88(1): 37Fibrillin-1 Deficient Mouse: Matrix Disruption in Aortic MediaNormal MouseFbn-1 Deficient MouseDisrupted Matrix Aortic AneurysmNormal Matrix No Aortic DilationFibrillin-1 Deficient Mouse: Fibrillin-1 Deficient Tissues Release MMPs Fibrillin-1 DeficiencyIncreased Matrix Metalloproteinases
6、(MMP) Matrix DisruptionAortic DilationMatrix Disruption in BAV PatientsAORTIC MEDIATricuspid AV (TAV)Bicuspid AV (BAV)Objective HypothesisIn BAV patients, fibrillin-1 deficiency and increased MMP matrix degradation result in aortic dilation Methods AortaFibrillin-1 Content Immunohistochemistry Fluor
7、escence Microscopy Quantitative Image AnalysisElastin 126(3): 797-806 Increased MMP-2 ActivityActiveBAV AortaTAV AortaLatentIncreased MMP-2 ActivityNovel Mechanism of Aortic DilationFBN-1 Gene Mutation (?)Decreased FBN-1 ProductionFBN-1 DeficiencySMC Detachment from Elastin LaminaeMMP-2 ReleaseMatri
8、x DegradationApoptosisMedial DegenerationAortic DilatationA Novel Mechanism for Aortic DilatationSecondary EventsAnatomic Patterns of Aortic Dilation Custom Tailoring RequiredPatterns of Aortic Dilation in Bicuspid Aortic Valves A: aortoventricular jxn B: Sinuses of Valsalva C: Sinotubular jxn D: Tu
9、bular ascending aorta E: Proximal innominate F: Distal innominate G: Proximal left subclavian H: Distal left subclavian I: Proximal descending J: Descending at diaphragmPatterns of Aortic Dilation in Bicuspid Aortic ValvesRoot (Sinuses) Dilation (Valved Conduit or Repair)Ascending Aorta (Supracorona
10、ry Graft)Ascending+Transverse Arch (RAA and Hemiarch)Aortopathy in Bicuspid ValveWhen Should the Ascending When Should the Ascending Aorta Be Replaced in Patients Aorta Be Replaced in Patients with Bicuspid Aortic Valve with Bicuspid Aortic Valve Disease?Disease?Borger, Fedak, Verma et al. JTCVS 200
11、5 Current recommendations for Current recommendations for replacement of the ascending aorta replacement of the ascending aorta (RAA):(RAA): 5.5 cm in diameter 5.5 cm in diameter 5.0 cm in Marfans patients 5.0 cm in Marfans patientsKouchoukos NT, Dougenis D. N Engl J Med 1997;336:1876-88 Optimal dia
12、meter for RAA in pts undergoing aortic valve surgery is unknown Hinge Point (6cm) may be different in BAV 30 times higher risk of post-operative dissection post AVR if AA 5.0cm Lower threshold for RAA in BAV patients (because of congenital aortopathy)? When Should RAA be Done in BAV Patients?When Sh
13、ould RAA be Done in BAV Patients? To determine incidence of long-term To determine incidence of long-term ascending aorta complications ascending aorta complications (aneurysm, dissection or sudden death) (aneurysm, dissection or sudden death) and survival in BAV pts with mild aortic and survival in
14、 BAV pts with mild aortic dilatation (40 50 mm) versus no dilatation (40 50 mm) versus no dilatationdilatation To determine the threshold diameter for RAA in BAV patients undergoing aortic valve surgeryPurpose of StudyPurpose of Study Diameter of ascending aorta determined by Diameter of ascending a
15、orta determined by direct measurement, TEE, or intaoperative direct measurement, TEE, or intaoperative description:description: “normal”“normal” less than 4.0 cm less than 4.0 cm “mildly dilated”“mildly dilated” 4.0 4.4 cm 4.0 4.4 cm “moderately dilated”“moderately dilated” 4.5 4.9 cm 4.5 4.9 cm Pat
16、ients with aortic diameters 5.0 cm underwent RAA and were excluded MethodsMethods Retrospective review of 201 BAV pts Retrospective review of 201 BAV pts undergoing aortic valve replacementundergoing aortic valve replacementBAV DysfunctionBAV DysfunctionPrevalence (%)JTCVS 2005ResultsResultsValve ProsthesisValve ProsthesisPrevalence (%)JTCVS 2005ResultsResultsCauses
