Digital Public Defence: Synne Frønæs Vikum Synne Frønæs Vikum at Institute of Clinical Medicine will be defending the thesis “Improving the diagnostic workup of deep vein thrombosis: FINDINGS FROM THE RI-SCHEDULE STUDY” for the degree of PhD (Philosophiae Doctor).

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The public defence will be held as a video conference over Zoom.

The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.

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Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.

Digital Trial Lecture – time and place

See Digital Trial Lecture.

Adjudication committee

  • First opponent: Associate Professor Kerstin de Wit, Queen's University and McMaster University, Canada
  • Second opponent: Professor Jan Beyer-Westendorf, Dresden University Hospital, Germany
  • Third member and chair of the evaluation committee: Professor Bjørn Bendz, University of Oslo

Chair of the Defence

Associate Professor Frede Jon Frihagen, University of Oslo

Principal Supervisor

Professor II Waleed Ghanima, University of Oslo


In the Rivaroxaban for Scheduled Workup of Deep Vein Thrombosis (the Ri-Schedule) study, we identified low-risk patients with suspected deep vein thrombosis (DVT) of the leg in whom diagnostic workup could be deferred while receiving empiric anticoagulation therapy with rivaroxaban. Furthermore, we found that it was safe to withhold ultrasound imaging tests if the laboratory marker D-dimer was normal. Our findings provide an easier option for anticoagulation therapy than the standard empiric treatment with low-molecular-weight heparin. They may also aid physicians in deciding in which patients diagnostic workup may safely be deferred. Moreover, relying solely on D-dimer instead of combining it with clinical pre-test probability assessment may reduce the number of unnecessary ultrasound examinations, and may allow for an easier and more streamlined diagnostic workup.

Patients with suspected DVT are typically referred from primary care to the hospital Emergency Department. If clinical evaluation reveals a perceived high pre-test likelihood of having DVT, or otherwise if the laboratory marker D-dimer is elevated, patients are referred for a diagnostic ultrasound imaging examination. Patients with isolated DVT of the leg are often not critically ill. Consequently, they often have to wait for a long time for diagnostic workup if there is a great influx of patients to the Emergency Department. Furthermore, they are routinely given empiric anticoagulation therapy and referred for hospital evaluation the following day if they present to primary care during off-hours.

The study was a prospective management outcome study with the overall aim of improving management of patients with suspected DVT. The study included patients referred to the Emergency Department at Østfold Hospital, Norway, with suspected DVT of the leg between February, 2015, and November, 2018.

Our findings may improve the management of patients with suspected lower-extremity DVT.

Additional information

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Published Mar. 4, 2022 11:23 AM - Last modified Mar. 30, 2022 1:26 PM