title: Venous thrombus stability during acute phase of therapy.
abstract: The purpose of this study was to use serial venous duplex scans to document the status of deep venous thrombi during the early phase of therapy for acute, deep-vein thrombosis (DVT). A total of 71 consecutive participants treated for a first episode of acute DVT were monitored for new venous thrombosis using serial venous duplex scans. An average of 4.6 duplex scans were performed per patient (range, three to seven) during the 3-week study period. The cumulative incidence of contiguous/non-contiguous extension of the DVT at 3 weeks was 26% (95% CI = 14% to 38%). Nine of the 15 (60%) occurrences were asymptomatic. None of the classical risk factors for DVT was significantly associated with the development of new thrombi. The fraction of time during which the level of anticoagulation was considered 'adequate' (international normalized ratio > or =2.0 and/or heparin concentration > or =0.2 IU/ml) was inversely associated with the risk of extension/new thrombi (p = 0.01, Cox proportional hazards analysis). It was concluded that: (1) the frequency of contiguous/non-contiguous extension of venous thrombosis detectable during the first 3 weeks of therapy was higher than previously reported; (2) the majority of the occurrences were asymptomatic; and (3) the risk of developing this complication was inversely associated with the level of anticoagulation achieved.
authors.affiliation: Department of Surgery, University of Washington School of Medicine, Seattle, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Caps
authors.forename: M H
authors.initials: MH
authors.lastname: Meissner
authors.forename: M J
authors.initials: MJ
authors.lastname: Tullis
authors.forename: N L
authors.initials: NL
authors.lastname: Polissar
authors.forename: R A
authors.initials: RA
authors.lastname: Manzo
authors.forename: B K
authors.initials: BK
authors.lastname: Zierler
authors.forename: W L
authors.initials: WL
authors.lastname: Chandler
authors.forename: D E
authors.initials: DE
authors.lastname: Strandness
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000097:blood / Q000627:therapeutic use*; D005260:Female; D006493:Heparin / Q000097:blood / Q000627:therapeutic use*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D016019:Survival Analysis; D018616:Ultrasonography, Doppler, Duplex; D020246:Venous Thrombosis / Q000097:blood / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D000925:Anticoagulants; D006493:Heparin