title: Prognostic significance of residual venous obstruction in patients with treated unprovoked deep vein thrombosis: a patient-level meta-analysis.
abstract: Residual venous obstruction (RVO) could improve the stratification of the risk of recurrence after unprovoked deep vein thrombosis (DVT), but results from clinical studies and study-level meta-analyses are conflicting. It was the objective of this analysis to determine if RVO is a valid predictor of recurrent venous thromboembolism (VTE) in patients with a first unprovoked DVT who had received at least three months of anticoagulant therapy. Individual patient data were obtained from the datasets of original studies, after a systematic search of electronic databases (Medline, Embase, Cochrane Library), supplemented by manual reviewing of the reference lists and contacting content experts. A multivariate, shared-frailty Cox model was used to calculate hazard ratios (HRs) for recurrent VTE, including, as covariates: RVO; age; sex; anticoagulation duration before RVO assessment; and anticoagulation continuation after RVO assessment. A total of 2,527 patients from 10 prospective studies were included. RVO was found in 1,380 patients (55.1%) after a median of six months from a first unprovoked DVT. Recurrent VTE occurred in 399 patients (15.8%) during a median follow-up of 23.3 months. After multivariate Cox analysis, RVO was independently associated with recurrent VTE (HR = 1.32, 95% confidence interval [CI]: 1.06-1.65). The association was stronger if RVO was detected early, i.e. at three months after DVT (HR = 2.17; 95% CI: 1.11-4.25), but non-significant if detected later, i.e. >6 months (HR = 1.19; 95% CI: 0.87-1.61). In conclusion, after a first unprovoked DVT, RVO is a weak overall predictor of recurrent VTE. The association is stronger if RVO is detected at an earlier time (3 months) after thrombosis.
authors.affiliation: Marco P. Donadini, Department of Clinical and Experimental Medicine, University of Insubria, Via Guicciardini, 9, 21100 Varese, Italy, Tel.: + 39 0332 278831, Fax: +39 0332 278818, E- mail: mp.donadini@gmail.com.
authors.forename: Marco P
authors.initials: MP
authors.lastname: Donadini
authors.forename: Walter
authors.initials: W
authors.lastname: Ageno
authors.forename: Emilia
authors.initials: E
authors.lastname: Antonucci
authors.forename: Benilde
authors.initials: B
authors.lastname: Cosmi
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kovacs
authors.forename: Grégoire
authors.initials: G
authors.lastname: Le Gal
authors.forename: Paul
authors.initials: P
authors.lastname: Ockelford
authors.forename: Daniela
authors.initials: D
authors.lastname: Poli
authors.forename: Paolo
authors.initials: P
authors.lastname: Prandoni
authors.forename: Marc
authors.initials: M
authors.lastname: Rodger
authors.forename: Giorgia
authors.initials: G
authors.lastname: Saccullo
authors.forename: Sergio
authors.initials: S
authors.lastname: Siragusa
authors.forename: Laura
authors.initials: L
authors.lastname: Young
authors.forename: Matteo
authors.initials: M
authors.lastname: Bonzini
authors.forename: Monica
authors.initials: M
authors.lastname: Caprioli
authors.forename: Francesco
authors.initials: F
authors.lastname: Dentali
authors.forename: Alfonso
authors.initials: A
authors.lastname: Iorio
authors.forename: James D
authors.initials: JD
authors.lastname: Douketis
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000737:chemistry / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D012008:Recurrence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017131:Thrombectomy; D013927:Thrombosis / Q000503:physiopathology*; D014463:Ultrasonography; D054556:Venous Thromboembolism / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control; D020246:Venous Thrombosis / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control
chemical_list: D000925:Anticoagulants
keywords: Residual venous obstruction; patient-level meta-analysis; recurrent venous thromboembolism; unprovoked deep vein thrombosis