Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.
Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Professor Emeritus Henrik Sillesen, University of Copenhagen, Denmark
- Second opponent: Associate Professor Elisabeth Kleivhaug Vesterbekkmo, NTNU: Norwegian University of Science and Technology,
- Third member and chair of the evaluation committee: Professor Helge Skulstad, University of Oslo
Chair of the Defence
Professor II Therese Sørlie, University of Oslo
Principal Supervisor
Professor Emeritus John Terje Geitung, University of Oslo
Summary
Simplified ultrasound measures capture only part of the atherosclerotic burden, whereas three-dimensional total plaque volume (TPV) is too cumbersome for use in clinical practice. This thesis evaluated weighted Total Plaque Thickness (wTPT), a novel two-dimensional ultrasound measure of plaque burden in the carotid and femoral arteries. It focused on reproducibility, validity and feasibility; associations with conventional cardiovascular (CV) risk factors and estimated 10-year risk; and discrimination of prevalent CV disease.
The thesis used data from the ongoing Prospective Screening of Non-invasive Atherosclerosis Risk (P-SONAR) cohort. 5,500 self-referred, self-paying adults aged 45–74 years underwent vascular ultrasound, clinical assessments and blood sampling at private clinics in Norway, this population that may not represent the general population. Reproducibility and validity were assessed in 60 participants. Associations with risk factors and NORRISK-2 were examined in 5,180 participants without known CV disease, and discrimination of prevalent disease in 5,418 participants.
wTPT showed excellent reproducibility and correlated strongly with TPV (ρ=0.98), while requiring only a fraction of the assessment time. Among participants without known CV disease, 96.1% had plaque. wTPT correlated slightly more strongly with NORRISK-2 than maximum plaque thickness, plaque count or number of arteries with plaque. Adding wTPT to conventional risk factors increased the c-statistic for prevalent CV disease from 0.84 to 0.88. Participants in the highest wTPT quartile had tenfold higher adjusted odds of prevalent disease than those in the lowest quartile.
wTPT is a feasible and reproducible measure of multiterritorial plaque burden and may provide information beyond conventional risk factors. However, these cross-sectional findings cannot show whether wTPT predicts future CV events. External and prospective validation is required before clinical implementation.
Additional information
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