title: Type and location of venous thromboembolism in patients with factor V Leiden or prothrombin G20210A and in those with no thrombophilia.
abstract: BACKGROUND
  Patients with factor (F) V Leiden or the prothrombin G20210A polymorphism are at increased risk of developing deep vein thrombosis (DVT). On the other hand, the risk of developing pulmonary embolism (PE) appears to be low in carriers of FV Leiden, perhaps because of a lower tendency to develop iliofemoral DVT than non-carriers. For prothrombin G20210A, data are scanty and controversial.
  
  
  METHODS
  The clinical manifestations (isolated DVT, DVT and PE, and isolated PE), the extension of DVT, and the presence of transient risk factors were retrospectively investigated in 115 patients with heterozygous FV Leiden, 87 with prothrombin G20210A and 200 with no thrombophilia marker.
  
  
  RESULTS
  Isolated symptomatic PE was less prevalent in patients with FV Leiden (6%) than in those with prothrombin G20210A (21%) and no thrombophilia (23%) (P > 0.0001). The rate of distal DVT was higher in patients with no thrombophilia (16% vs. 7% for FV Leiden and 6% for prothrombin G20210A) (P = 0.02). No difference in the incidence of PE from distal and proximal DVT, the extension of proximal DVT and the type of transient risk factors for venous thromboembolism (VTE) was found in the three groups. Patients with prothrombin G20210A had a younger age at their first VTE (24 years, P < 0.0001) and a higher rate of DVT accompanying PE (P = 0.04) than those with FV Leiden or no thrombophilia.
  
  
  CONCLUSIONS
  Carriers of prothrombin G20210A, unlike those of FV Leiden, have an increased risk of developing isolated PE. This difference was not explained by a different rate of distal DVT, extension of proximal DVT, or distribution of transient risk factors in the two groups. Patients with prothrombin G20210A have more severe clinical manifestations than those with FV Leiden or no thrombophilia.
authors.affiliation: Department of Internal Medicine and Medical Specialties, Bianchi Bonomi Haemophilia and Thrombosis Center, IRCCS Maggiore Hospital Policlinico, Mangiagalli and Regina Elena Foundation and University of Milan, Milan, Italy. martin@policlinico.mi.it
authors.forename: I
authors.initials: I
authors.lastname: Martinelli
authors.forename: T
authors.initials: T
authors.lastname: Battaglioli
authors.forename: C
authors.initials: C
authors.lastname: Razzari
authors.forename: P M
authors.initials: PM
authors.lastname: Mannucci
mesh_terms: D000225:Adenine; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000375:Aging; D002648:Child; D015331:Cohort Studies; D005165:Factor V / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006147:Guanine; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D011516:Prothrombin / Q000235:genetics*; D011655:Pulmonary Embolism / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D019851:Thrombophilia / Q000235:genetics*; D020246:Venous Thrombosis / Q000150:complications / Q000453:epidemiology / Q000235:genetics*
chemical_list: C095381:factor V Leiden; D006147:Guanine; D005165:Factor V; D011516:Prothrombin; D000225:Adenine