Growth rates of small abdominal aortic aneurysms assessed by computerised tomography--a systematic literature review.
BACKGROUND
Most current evidence examining abdominal aortic aneurysm (AAA) growth is based on ultrasound surveillance.


OBJECTIVE
This review aimed to systematically analyse studies which have assessed small AAA growth using computed tomography (CT) to monitor outcome.


METHODS
Studies investigating small AAA expansion rates using CT images were identified by searching the PubMed database and hand searching article reference lists. Eligible studies must have focused on monitoring small AAA growth using CT and included patients with baseline AAA diameters <55 mm for which growth rates were reported.


RESULTS
Ten studies including 845 patients met eligibility with average baseline AAA diameters ranging from 36.2 to 50.5 mm. AAA growth was assessed using axial (n = 1), orthogonal (n = 2), anterior to posterior (n = 4), and unspecified (n = 3) measurement methods. One study reported the reproducibility of their assessment method. Mean AAA diameter growth rates ranged from 2.6 to 5.2 mm/year. Factors reported to be associated with increased AAA expansion included: large AAA thrombus size (n = 3 studies), large baseline AAA diameter (n = 2), high AAA wall stress, elevated plasma concentration of matrix metalloproteinase-9 and presence of carotid artery disease (n = 1 study each). Factors reported to be negatively associated with AAA growth included presence of diabetes mellitus and chronic limb ischaemia (n = 1 study each).


CONCLUSIONS
Many currently reported studies assessing small AAA growth on CT fail to report consistent use of reproducible measurement methods. CT offers the opportunity to assess orthogonal diameter and perform central reading which could be an advantage of this form of imaging.
Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia.
Kerolos
K
Hendy
Cairns Clinical School, Cairns Base Hospital, School of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia; Research and Development Unit, Primary Health Care and Dental Care, Southern Älvsborg County Region, Västra Götaland, Sweden; Department of Public Health and Community Medicine, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Sweden.
Ronny
R
Gunnarson
Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia; Department of Vascular and Endovascular Surgery, The Townsville Hospital, Townsville, QLD 4811, Australia. Electronic address: jonathan.golledge@jcu.edu.au.
Jonathan
J
Golledge
D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging*; D015415:Biomarkers / Q000097:blood; D002340:Carotid Artery Diseases / Q000097:blood; D018450:Disease Progression; D004730:Endothelium, Vascular / Q000473:pathology; D005121:Extremities / Q000473:pathology; D005260:Female; D006801:Humans; D007511:Ischemia / Q000150:complications; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000097:blood; D012307:Risk Factors; D013927:Thrombosis / Q000473:pathology; D014057:Tomography, X-Ray Computed
D015415:Biomarkers; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9
Abdominal aortic aneurysm; Computer tomography; Growth rate