Endovascular AAA repair: classification of aneurysm sac volumetric change using spiral computed tomographic angiography.
OBJECTIVE
To classify and analyze the volumetric changes seen on spiral computed tomographic angiography (CTA) following endovascular abdominal aortic aneurysm (AAA) repair.


METHODS
Fifty patients (46 men; mean age 71 years, range 51-83) with >1 year of imaging follow-up were retrospectively selected. The volume of the aneurysm sac was calculated on standard CT workstations to obtain plots of volume changes over time. For the purpose of this study, a 10% change in sac volume was considered significant.


RESULTS
Over a mean 32-month follow-up, 256 CTA scans were performed; initial mean sac volume was 259 mL and initial mean AAA diameter was 6.5 cm. Six distinct patterns of volume change were recognized: group Ia (28 patients, 56%): progressive reduction in aneurysm sac volume; group Ib (3 patients, 6%): transient initial increase then same as Ia; group II (4 patients, 8%): no significant change; group IIIa (5 patients, 10%): late increase in volume; group IIIb (8 patients, 16%): progressive increase in volume; and group IV (2 patients, 4%): late reduction in volume after secondary intervention. Group III changes were associated with endoleak types I and III (p<0.0001).


CONCLUSIONS
This classification system of spiral CTA volumetric changes features 6 patterns with recognized clinical significance and predictive value for endoleaks. Group I is the ideal outcome when the aneurysm sac shrinks and often completely disappears, while group III is associated with types I and type III endoleak and should prompt further investigation. Long-term volumetric analysis of all patients is advised.
Pollock
John G
JG
Department of Clinical Radiology, Queens Medical Center, University Hospital, Nottingham, UK.
Travis
Simon J
SJ
Whitaker
Simon C
SC
Davidson
Ian R
IR
Gregson
Roger H S
RH
Hopkinson
Brian R
BR
Wenham
Peter W
PW
MacSweeney
Shane T
ST
D000368:Aged; D000792:Angiography; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000628:therapy*; D019917:Blood Vessel Prosthesis Implantation; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000453:epidemiology; D015607:Stents; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods