Clinical outcome and morphologic determinants of mural thrombus in abdominal aortic endografts.
OBJECTIVE
Endograft mural thrombus has been associated with stent graft or limb thrombosis after endovascular aneurysm repair (EVAR). This study aimed to identify clinical and morphologic determinants of endograft mural thrombus accumulation and its influence on thromboembolic events after EVAR.


METHODS
A prospectively maintained database of patients treated by EVAR at a tertiary institution from 2000 to 2012 was analyzed. Patients treated for degenerative infrarenal abdominal aortic aneurysms and with available imaging for thrombus analysis were considered. All measurements were performed on three-dimensional center-lumen line computed tomography angiography (CTA) reconstructions. Patients with thrombus accumulation within the endograft's main body with a thickness >2 mm and an extension >25% of the main body's circumference were included in the study group and compared with a control group that included all remaining patients. Clinical and morphologic variables were assessed for association with significant thrombus accumulation within the endograft's main body by multivariate regression analysis. Estimates for freedom from thromboembolic events were obtained by Kaplan-Meier plots.


RESULTS
Sixty-eight patients (16.4%) presented with endograft mural thrombus. Median follow-up time was 3.54 years (interquartile range, 1.99-5.47 years). In-graft mural thrombus was identified on 30-day CTA in 22 patients (32.4% of the study group), on 6-month CTA in 8 patients (11.8%), and on 1-year CTA in 17 patients (25%). Intraprosthetic thrombus progressively accumulated during the study period in 40 patients of the study group (55.8%). Overall, 17 patients (4.1%) presented with endograft or limb occlusions, 3 (4.4%) in the thrombus group and 14 (4.1%) in the control group (P = .89). Thirty-one patients (7.5%) received an aortouni-iliac (AUI) endograft. Two endograft occlusions were identified among AUI devices (6.5%; overall, 0.5%). None of these patients showed thrombotic deposits in the main body, nor were any outflow abnormalities identified on the immediately preceding CTA. Estimated freedom from thromboembolic events at 5 years was 95% in both groups (P = .97). Endograft thrombus accumulation was associated with >25% proximal aneurysm neck thrombus coverage at baseline (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.1-3.3), neck length ≤ 15 mm (OR, 2.4; 95% CI, 1.3-4.2), proximal neck diameter ≥ 30 mm (OR, 2.4; 95% CI, 1.3-4.6), AUI (OR, 2.2; 95% CI, 1.8-5.5), or polyester-covered stent grafts (OR, 4.0; 95% CI, 2.2-7.3) and with main component "barrel-like" configuration (OR, 6.9; 95% CI, 1.7-28.3).


CONCLUSIONS
Mural thrombus formation within the main body of the endograft is related to different endograft configurations, main body geometry, and device fabric but appears to have no association with the occurrence of thromboembolic events over time.
Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Angiology and Vascular Surgery, Hospital do Divino Espírito Santo, Ponta Delgada, Azores, Portugal. Electronic address: n.gomesoliveira@erasmusmc.nl.
Nelson F G
NF
Oliveira
Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Angiology and Vascular Surgery, Hospital de Santa Marta, Centro Hospitalar de Lisboa Central, Lisbon, Portugal.
Frederico M
FM
Bastos Gonçalves
Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
Sanne E
SE
Hoeks
Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
Sander
S
Ten Raa
Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
Klass H J
KH
Ultee
Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
Ellen
E
Rouwet
Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
Johanna M
JM
Hendriks
Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
Hence J M
HJ
Verhagen
D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001807:Blood Vessel Prosthesis / Q000009:adverse effects*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation* / Q000401:mortality; D016009:Chi-Square Distribution; D016208:Databases, Factual; D018572:Disease-Free Survival; D057510:Endovascular Procedures / Q000009:adverse effects* / Q000295:instrumentation* / Q000401:mortality; D005260:Female; D006083:Graft Occlusion, Vascular / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011174:Portugal; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents / Q000009:adverse effects*; D062606:Tertiary Care Centers; D013927:Thrombosis / Q000175:diagnosis / Q000209:etiology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome