title: Complement component C5a predicts restenosis after superficial femoral artery balloon angioplasty.
abstract: OBJECTIVE
  To investigate whether balloon angioplasty of the superficial femoral artery (SFA) increases serum levels of C5a and whether C5a predicts risk of restenosis.
  
  
  METHODS
  C5a antigen was measured at baseline and 8 hours after intervention in 131 consecutive patients (76 women; median age 72 years) with intermittent claudication who underwent successful primary SFA balloon angioplasty. Patients were followed for a median 10 months [interquartile range (IQR) 6 to 14] for the occurrence of >50% restenosis by duplex ultrasound.
  
  
  RESULTS
  Median C5a levels increased significantly from 39.7 ng/mL (IQR 27.8 to 55.0) at baseline to 53.8 ng/mL (IQR 35.6 to 85.1, p<0.001) 8 hours post intervention. During the follow-up period, 70 (53%) patients developed restenosis. Increasing levels of C5a (quartiles) at baseline were significantly associated with an increased risk for restenosis (p=0.0092). Adjusted hazard ratios (95% confidence intervals) for restenosis with increasing quartiles of baseline serum C5a levels were 1.24 (0.60 to 2.58), 1.93 (0.95 to 3.93), and 2.08 (1.02 to 4.21), respectively, compared to the lowest quartile. This effect was independent of nonspecific inflammation as reflected by plasma levels of C-reactive protein.
  
  
  CONCLUSIONS
  Inflammatory mechanisms play a major role in the development of restenosis after angioplasty. The complement component C5a exerts strong chemotactic and proinflammatory effects. Enhanced complement activation prior to PTA, as measured by higher levels of C5a, was significantly associated with restenosis after SFA balloon angioplasty. Pathways of complement inhibition thus may be worth investigating with respect to improving patency rates.
authors.affiliation: Departments of Internal Medicine II, Medical University of Vienna, Austria. walter.speidl@meduniwien.ac.at
authors.forename: Walter S
authors.initials: WS
authors.lastname: Speidl
authors.forename: Markus
authors.initials: M
authors.lastname: Exner
authors.forename: Jasmin
authors.initials: J
authors.lastname: Amighi
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Mlekusch
authors.forename: Schila
authors.initials: S
authors.lastname: Sabeti
authors.forename: Stefan P
authors.initials: SP
authors.lastname: Kastl
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Zorn
authors.forename: Gerald
authors.initials: G
authors.lastname: Maurer
authors.forename: Oswald
authors.initials: O
authors.lastname: Wagner
authors.forename: Kurt
authors.initials: K
authors.lastname: Huber
authors.forename: Erich
authors.initials: E
authors.lastname: Minar
authors.forename: Johann
authors.initials: J
authors.lastname: Wojta
authors.forename: Martin
authors.initials: M
authors.lastname: Schillinger
mesh_terms: D000368:Aged; D000800:Angioplasty, Balloon / Q000009:adverse effects; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000276:immunology* / Q000503:physiopathology / Q000601:surgery*; D015331:Cohort Studies; D015936:Complement C5a / Q000378:metabolism*; D003251:Constriction, Pathologic / Q000601:surgery; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D007383:Intermittent Claudication / Q000209:etiology; D008297:Male; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012008:Recurrence; D012107:Research Design; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014654:Vascular Patency
chemical_list: D015936:Complement C5a