title: Evolution of deep venous thrombosis: a 2-year follow-up using duplex ultrasound scan and strain-gauge plethysmography.
abstract: OBJECTIVE
  The development of the post-thrombotic syndrome (PTS) and recurrence of deep venous thrombosis (DVT) are not yet fully understood. The aim of the study was to identify factors that lead to the long-term complications of DVT.
  
  
  METHODS
  In a 2-year prospective follow-up study, duplex scanning and strain-gauge plethysmography were used to evaluate DVT in relation to the development of long-term complications. Each of the 12 segments examined was assigned as a thrombosis score (TS). A total TS was calculated for each leg. Patent segments were assigned a TS = 0, noncompressible vein segments with flow TS = 1 and noncompressible vein segments without flow TS = 2. The degree of resolution of DVT and the incidence, timing, and outcome of further thrombotic events were measured during 24 months of follow-up.
  
  
  RESULTS
  The study involved 86 legs with DVT. The 2-year follow-up was completed for 70 legs. Within 3 months, only 1% of the originally occluded proximal deep vein segments were still occluded. Between all time intervals, from month 12 to month 24, for example, thrombus regression continued in 36% of the legs and thrombus propagation continued in 27%. Multiple regression analysis revealed that an increase in age (P = .008) and proximal location of the original DVT (P = .05) was significantly related to thrombus propagation. Multiple regression analysis showed that the risk factors for clinical signs of PTS were a high venous outflow resistance after 1-month and 12-month follow-ups (P <or= .002) and a high thrombosis score in the proximal veins after 3 months (P = .008).
  
  
  CONCLUSIONS
  In the follow-up of older patients and patients with proximal DVT, evolution was shown to be an unstable process with continuing propagation for 2 years. The risk factors for the development of PTS were a slow decrease in venous outflow resistance or a high thrombosis score of the proximal veins after 3 months.
authors.affiliation: Clinical Vascular Laboratory, University Hospital, Nijmegen, The Netherlands. J.Haenen@vasclab.azn.nl
authors.forename: J H
authors.initials: JH
authors.lastname: Haenen
authors.forename: H
authors.initials: H
authors.lastname: Wollersheim
authors.forename: M C
authors.initials: MC
authors.lastname: Janssen
authors.forename: M A
authors.initials: MA
authors.lastname: Van 't Hof
authors.forename: P M
authors.initials: PM
authors.lastname: Steijlen
authors.forename: H
authors.initials: H
authors.lastname: van Langen
authors.forename: S H
authors.initials: SH
authors.lastname: Skotnicki
authors.forename: T
authors.initials: T
authors.lastname: Thien
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use; D001458:Bandages; D003131:Combined Modality Therapy; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010991:Plethysmography / Q000379:methods*; D012008:Recurrence; D012044:Regression Analysis; D012307:Risk Factors; D012720:Severity of Illness Index; D016037:Single-Blind Method; D013577:Syndrome; D013997:Time Factors; D018616:Ultrasonography, Doppler, Duplex / Q000379:methods*; D014655:Vascular Resistance; D020246:Venous Thrombosis / Q000145:classification / Q000150:complications* / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy
chemical_list: D000925:Anticoagulants