title: A histological and functional description of the tissue causing chronic postthrombotic venous obstruction.
abstract: BACKGROUND
  Postthrombotic intraluminal tissue causing postthrombotic syndrome (PTS) has not been well described. This study defines its histological characteristics and assess whether tissue function evolves over time.
  
  
  METHODS
  Specimens from 18 common femoral veins (CFV) from 16 patients obtained during CFV endovenectomy and iliocaval recanalization were examined. Phase 1 used hematoxylin and eosin and Masson's trichrome stains for collagen, immunohistochemical, and Von Kossa stains. Phase 2 examined young (≤ one year) and mature (≥10years from acute DVT) specimens to evaluate evolution of endothelial function. Antibodies to four biomarkers were used to examine specific functions of endothelial cells lining neovessels and recanalization channels (RC).
  
  
  RESULTS
  Phase 1: Specimens demonstrated 80-90% of collagen type I, 10-20% of collagen type III, and dystrophic calcification. Neovessels and RC were in close proximity to each other. Thrombus and smooth muscle cells were absent, but white blood cells were present. Phase 2: VEGFR2 receptor uptake was more abundant in neovessels than RC and more prominent in younger specimens. Neovascular, nonchannel cells were observed more frequently in young specimens. CD-31 was similar in young and mature specimens. TIE-2 and von Willebrand factor antibodies had greater uptake in mature specimens.
  
  
  CONCLUSIONS
  Tissue causing chronic postthrombotic venous obstruction is predominantly type I collagen. Neovascularization and recanalization occur in close proximity. The biomarker for neovascularization and angiogenesis (VEGFR2) was more prominent in young specimens whereas TIE-2, a stabilizing biomarker and vWF were more frequently observed in mature specimens.
authors.affiliation: Jobst Vascular Institute, Toledo, OH, USA. Electronic address: shakela.watkins@promedica.org.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Comerota
authors.affiliation: Jobst Vascular Institute, Toledo, OH, USA.
authors.forename: Carson
authors.initials: C
authors.lastname: Oostra
authors.affiliation: Jobst Vascular Institute, Toledo, OH, USA.
authors.forename: Ziad
authors.initials: Z
authors.lastname: Fayad
authors.affiliation: The University of Toledo, College of Medicine, USA.
authors.forename: William
authors.initials: W
authors.lastname: Gunning
authors.affiliation: The Conrad Jobst Vascular Research Laboratory, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Henke
authors.affiliation: The Conrad Jobst Vascular Research Laboratory, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Luke
authors.affiliation: ProMedica Toledo Hospital, Department of Pathology, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Lynn
authors.affiliation: Jobst Vascular Institute, Toledo, OH, USA.
authors.forename: Fedor
authors.initials: F
authors.lastname: Lurie
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015415:Biomarkers; D002114:Calcinosis / Q000473:pathology / Q000503:physiopathology; D003094:Collagen / Q000032:analysis; D042783:Endothelial Cells / Q000737:chemistry; D004730:Endothelium, Vascular / Q000473:pathology; D005260:Female; D005268:Femoral Vein / Q000473:pathology / Q000601:surgery; D006801:Humans; D007962:Leukocytes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000209:etiology / Q000473:pathology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D054070:Postthrombotic Syndrome / Q000473:pathology* / Q000503:physiopathology; D042787:Receptor, TIE-2 / Q000032:analysis; D016037:Single-Blind Method; D013194:Staining and Labeling; D013924:Thrombophlebitis / Q000473:pathology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000032:analysis; D014656:Vascular Surgical Procedures; D014841:von Willebrand Factor / Q000032:analysis
chemical_list: D015415:Biomarkers; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D014841:von Willebrand Factor; D003094:Collagen; C000588866:KDR protein, human; D042787:Receptor, TIE-2; D040301:Vascular Endothelial Growth Factor Receptor-2
keywords: Collagen; Iliofemoral DVT; Postthrombotic syndrome; Thrombosis; Venous hypertension; Venous obstruction