title: [Hereditary disorders of the protein C system in central artery and branch arteriolar occlusions].
abstract: BACKGROUND
  Resistance to activated protein C (APC) is the most common hereditary defect in patients with venous thrombosis. There are conflicting reports on the prevalence of APC resistance in patients with arterial thrombosis, e.g. coronary arteries, compared to the APC resistance prevalence among the normal population. The prevalence of APC resistance in branch retinal artery occlusion (BRAO) and central retinal artery occlusion (CRAO) is unknown.
  
  
  METHODS
  29 consecutive patients with arterial retinal occlusions (BRAO, n = 12; CRAO, n = 17) were included in this prospective study over a 23-months-period. We searched for APC resistance, protein C or S deficiencies, as well as for acquired vascular risk factors. Factor-V-deficient plasma and genetic analysis with a PCR method were employed for APC resistance determination. Protein C and protein S activity were determined with functional tests.
  
  
  RESULTS
  APC resistance was found in 3 of 29 patients (10.3%). Two of these patients had BRAO and one patient CRAO. Comparing this prevalence to the APC resistance prevalence within the normal population (9%), the difference was not statistically significant. 27 patients (93.1%) had one or more vascular risk factors (arterial hypertension = 19 [65.5%], hyperlipidaemia = 14 [48.2%], smoking = 7 [24.1%], diabetes mellitus = 5 [17.2%], carotid artery stenosis = 5 [17.2%]).
  
  
  CONCLUSIONS
  We could not find an increased prevalence of APC resistance in patients with CRAO or BRAO when compared to the normal population.
authors.affiliation: Augenklinik, Universitätsklinikum Mainz.
authors.forename: K
authors.initials: K
authors.lastname: Greiner
authors.forename: G
authors.initials: G
authors.lastname: Hafner
authors.forename: W
authors.initials: W
authors.lastname: Prellwitz
authors.forename: N
authors.initials: N
authors.lastname: Pfeiffer
mesh_terms: D020016:Activated Protein C Resistance / Q000097:blood / Q000175:diagnosis / Q000235:genetics*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011486:Protein C / Q000378:metabolism; D020151:Protein C Deficiency / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D017293:Protein S / Q000378:metabolism; D018455:Protein S Deficiency / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D015356:Retinal Artery Occlusion / Q000097:blood / Q000175:diagnosis / Q000235:genetics*; D012307:Risk Factors; D019851:Thrombophilia / Q000097:blood / Q000175:diagnosis / Q000235:genetics*
chemical_list: D011486:Protein C; D017293:Protein S
vernacular_title: Hereditäre Störungen des Protein-C-Systems bei Zentralarterien- und Arteriolenastverschlüssen.