title: Management and outcomes of single subsegmental pulmonary embolus: a retrospective audit at North Shore Hospital, New Zealand.
abstract: BACKGROUND
  It is unknown whether filling defects in subsegmental arteries on multidetector computed tomography pulmonary angiography correlate with clinically relevant subsegmental pulmonary embolism (PE) on pulmonary angiography. Current guidelines do not differentiate between PE in segmental and subsegmental vessels, and many patients receive at least 3 months anticoagulation. The strategy employed at North Shore Hospital in haemodynamically stable patients with single subsegmental PE is to perform bilateral lower leg compression ultrasound (CUS). Anticoagulation is withheld if CUS is negative; a bilateral CUS is repeated in 7-10 days.
  
  
  OBJECTIVE
  The aim of this retrospective audit was to ensure our current management strategy is safe.
  
  
  METHODS
  All diagnoses of single subsegmental PE between June 2005 and June 2013 were included. The primary outcome was the rate of venous thromboembolism (VTE) recurrence within 3 months of single subsegmental PE diagnosis. Secondary outcomes were rates of major/minor bleeding and all-cause mortality.
  
  
  RESULTS
  Thirty-two patients were included - 20 were treated with anticoagulation; 12 were managed with observation/serial bilateral lower limb CUS. None of the patients in either group had VTE recurrence by 3 months. No bleeding episodes were observed in the observation group; there was a 10% major bleeding rate (n = 2) in the treatment group. One death occurred in each group, neither of which was attributed to VTE.
  
  
  CONCLUSIONS
  Withholding anticoagulation in patients with single subsegmental PE and negative serial bilateral CUS appears to be a safe and effective management strategy, with a low risk of VTE recurrence.
authors.affiliation: Department of Radiology, North Shore Hospital, Auckland, New Zealand.
authors.forename: D
authors.initials: D
authors.lastname: Mehta
authors.forename: M
authors.initials: M
authors.lastname: Barnett
authors.forename: L
authors.initials: L
authors.lastname: Zhou
authors.forename: T
authors.initials: T
authors.lastname: Woulfe
authors.forename: V
authors.initials: V
authors.lastname: Rolfe-Vyson
authors.forename: V
authors.initials: V
authors.lastname: Rowland
authors.forename: D
authors.initials: D
authors.lastname: Simpson
authors.forename: E
authors.initials: E
authors.lastname: Merriman
mesh_terms: D000368:Aged; D000792:Angiography; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D054869:Clinical Audit; D003250:Constriction; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009520:New Zealand / Q000453:epidemiology; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D012008:Recurrence; D012189:Retrospective Studies; D016896:Treatment Outcome; D014463:Ultrasonography / Q000379:methods; D054556:Venous Thromboembolism / Q000150:complications* / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D000925:Anticoagulants
keywords: diagnosis; multidetector computed tomography; pulmonary embolism; therapy; venous thromboembolism