title: Mural thrombus and the progression of abdominal aortic aneurysms: a large population-based prospective cohort study.
abstract: OBJECTIVE
  To investigate whether the relative size of intraluminal thrombus (ILT) in abdominal aortic aneurysms (AAAs) is associated with AAA growth.
  
  
  METHODS
  This large observational study was based on a randomised population-based screening trial. Six hundred and fifteen AAAs were diagnosed in men aged 65-74 years. The relative cross-sectional area covered by the mural thrombus was estimated by a semiautomatic method using ultrasound equipment to measure the area of the ellipses, and adapting the inner ellipse (IA) to the luminal border of the thrombus and the outer ellipse to the area inside the media border (OA). The relative thrombus area was then calculated as ((OA-IA)/OU) × 100%. Four hundred and sixteen of the patients with AAA were eligible for analysis.
  
  
  RESULTS
  The mean size of the AAA was 40.6 mm, and the mean observation time was 1.78 years. In the group with AAAs measuring 30-34 mm, 42% had ILT, with a mean relative size of 12% of the outer area. In the group with AAAs measuring >64 mm, the presence of ILT increased to 100%, with a mean relative size of 70% of the outer area. Univariate analysis showed relative ILT size, aortic diameter, smoking history, and diastolic blood pressure were significantly positively associated with growth rate, while the presence of diabetes mellitus was significantly negatively associated with growth rate. The relative ILT size remained significantly positively associated with the growth rate after a multivariate linear regression adjusting for potential confounders.
  
  
  CONCLUSIONS
  These findings suggest that ILT may play a part in the progression of AAAs.
authors: Vascular Research Unit, Department of Vascular Surgery, Viborg Hospital, Heibergs Alle 4, 8800 Viborg, Denmark. Electronic address: carsten.behr.rasmussen@viborg.rm.dk.
authors: C
authors: C
authors: Behr-Rasmussen
authors: Vascular Research Unit, Department of Vascular Surgery, Viborg Hospital, Heibergs Alle 4, 8800 Viborg, Denmark.
authors: N
authors: N
authors: Grøndal
authors: Vascular Research Unit, Department of Vascular Surgery, Viborg Hospital, Heibergs Alle 4, 8800 Viborg, Denmark.
authors: M B
authors: MB
authors: Bramsen
authors: Vascular Research Unit, Department of Vascular Surgery, Viborg Hospital, Heibergs Alle 4, 8800 Viborg, Denmark.
authors: M D
authors: MD
authors: Thomsen
authors: Vascular Research Unit, Department of Vascular Surgery, Viborg Hospital, Heibergs Alle 4, 8800 Viborg, Denmark; Department of Thoracic, Heart, and Vascular Surgery, Odense University Hospital, University of Southern Denmark, Sdr. Boulevard 29, 5000 Odense C, Denmark.
authors: J S
authors: JS
authors: Lindholt
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology*; D003718:Denmark; D018450:Disease Progression; D006801:Humans; D008297:Male; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000473:pathology*; D014463:Ultrasonography
keywords: Abdominal aortic aneurysms; Intraluminal thrombus; Ultrasonographic scan