title: Impact of ventilation/perfusion single-photon emission computed tomography on treatment duration of pulmonary embolism.
abstract: OBJECTIVE
  The aim of the study was to establish whether the duration of anticoagulant (AC) therapy can be tailored, on an objective basis, by using ventilation/perfusion single-photon emission computed tomography (V/P SPECT) and to assess the extent of residual perfusion defects over time. In particular, we addressed the following: (a) is the extent of perfusion recovery at 3 months of initial pulmonary embolism (PE) diagnosis a satisfactory criterion for deciding the duration of oral AC? (b) Is it safe to withdraw AC at 3 months if perfusion recovery is complete?
  
  
  METHODS
  Of 269 consecutive patients with suspected PE, 100 patients were diagnosed with PE using V/P SPECT. Sixty-seven patients with acute PE were followed up clinically and with V/P SPECT at 3 months. Sixty-four patients were subject to review and examination using V/P SPECT for a period of 6 months and 33 were followed up only clinically. Therapy was terminated after 3 months if perfusion was normalized, and patients were free of symptoms and the risk of hypercoagulability. Initial extension of PE did not have an impact on decision making.
  
  
  RESULTS
  PE extension varied from 10 to 70% in the acute stage. After 3 months, complete resolution of PE was found in 48 patients. The treating pulmonologist decided to terminate therapy in 35 (73%) patients and to continue AC in 13 patients because of persistent risk factors. Six months later, at the second control stage, 53 patients had complete recovery of pulmonary perfusion. Eleven patients still had perfusion defects at 6 months. No recurrence was identified at 6 months in the 35 patients whose therapy was terminated after 3 months. No bleeding effects were observed in any of the patients during the 6-month follow-up.
  
  
  CONCLUSIONS
  This study shows that AC therapy can be tailored, on an objective basis, by using V/P SPECT. Normalization of perfusion at 3 months of initial PE diagnosis was a reliable indicator that AC could be safely withdrawn in patients who were without hypercoagulability risk.
authors.affiliation: aClinic for Nuclear Medicine bClinic for Pulmonology, Clinical Centre, University Hospital of Sarajevo, Sarajevo, Bosnia and Hercegovina cDepartment of Medical Imaging and Physiology, Skane University Hospital and Lund University, Lund, Sweden dDepartment of Experimental and Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Amela
authors.initials: A
authors.lastname: Begic
authors.forename: Emina
authors.initials: E
authors.lastname: Opanković
authors.forename: Vesna
authors.initials: V
authors.lastname: Čukić
authors.forename: Medzida
authors.initials: M
authors.lastname: Rustempašić
authors.forename: Amila
authors.initials: A
authors.lastname: Bašić
authors.forename: Massimo
authors.initials: M
authors.lastname: Miniati
authors.forename: Jonas
authors.initials: J
authors.lastname: Jögi
authors.forename: Marika
authors.initials: M
authors.lastname: Bajc
mesh_terms: D000925:Anticoagulants / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D059012:Lost to Follow-Up; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D012123:Pulmonary Ventilation / Q000187:drug effects*; D012039:Regional Blood Flow / Q000187:drug effects*; D012449:Safety; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants