Abstract
The study aimed to evaluate the morphologic changes in transarterial chemoembolization (TACE) puncture sites implanted with an ExoSeal vascular closure device (VCD) using follow-up computed tomography (CT). Materials and Methods: 16 patients who used ExoSeal VCD after TACE were enrolled. Using CT images, the diameters and anterior wall thicknesses of the puncture sites in the common femoral artery (CFA) were compared with those of the contralateral CFA before TACE, at 1 month after every TACE session, and at the final follow-up period. The rates of complications were also evaluated. Results: There were no puncture-or VCD-related complications. Follow-up CT images of the CFA's of patients who used ExoSeal VCDs showed eccentric vascular wall thickening with soft-tissue densities considered to be hemostatic plugs. Final follow-up CT images (mean, 616 days; range, 95-1106 days) revealed partial or complete resorption of the hemostatic plugs. The CFA puncture site diameters did not differ statistically from those of the contralateral CFA on the final follow-up CT (p > 0.05), regardless of the number of VCDs used. Conclusion: Follow-up CT images of patients who used ExoSeal VCDs showed no significant vascular stenosis or significant vessel wall thickening. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
INTRODUCTION
Regional cancer therapy procedures such as transarterial chemoembolization (TACE) have become mainstay in the treatment of unresectable primary and metastatic hepatic malignancies. TACE extends the life expectancy of patients with advanced hepatocellular carcinoma, and it is now widely used for palliation.
Arterial puncture is required to deliver chemotherapeutic agents to a hepatic tumor. In fact, patients often require one or more additional arterial punctures to treat partially cured or new lesions.
Safe and effective catheter-directed therapy can increase survival in this population which often has other associated comorbid conditions (1) (2) (3) . The vascular closure device (VCD) is widely used in this population for patient comfort and safety (4, 5) .
In the mid-1990s, the VCD was introduced into clinical practice with the aim of improving the efficacy and safety of percutaneous procedures (6) . The devices are implanted to close the arteriotomy site of the vessel wall by targeted force. Different types of VCDs have been developed, including intravascular and extravascular devices (7, 8) . Increased efficacy, i.e., decreased time to hemostasis and earlier ambulation, has been a consistent finding in different VCD trials compared with manual compres- (9) (10) (11) . VCD is preferred to manual compression in patients with coagulopathy (12, 13) . The common femoral artery (CFA) is the most common puncture site and is usually included in the scanning range of follow-up abdominal CT images.
However, changes in puncture sites after VCD insertion have seldom been reported.
The purpose of this study is to evaluate the morphologic changes in TACE puncture sites after VCD (ExoSeal; Cordis, Miami Lakes, FL, USA) implantation in patients using followup CT.
MATERIALS AND METHODS

Study Population
Our hospital's institutional review board approved this retrospective study and waived the informed consent requirement.
We performed 628 TACE procedures in 600 patients between tion was not performed before or after TACE (n = 4), 2) CFA images were not included in the pre-or post-TACE CT (n = 2), 3) both ExoSeal and another VCD were used in one patient during the study period (n = 2). A total of 16 patients (4 females, 12 males; mean age, 62.3 years; range, 45-78 years) were enrolled in this study. The mean serum platelet count was 64875/µL (range, 29000-161000) and mean PT-INR was 1.23 (range, 0.97-1.49).
The demographic data of these 16 patients are summarized in Table 1 . 
Closure of Arterial Puncture
All TACE procedures were performed via 5F sheath access in the right CFA. Upon completion, puncture sites were closed using an ExoSeal VCD. The VCDs were implanted by one author with 8 years of experience in interventional radiology (U.B.J.).
Anticoagulation status and body habitus were assessed at the time of closure to ensure appropriate choice of closure device.
After closure, patients were restricted to bedrest for 3 hours and then allowed to ambulate. Any evidence of complications was recorded and appropriate therapy was initiated.
Image Analysis
The CT images were evaluated to consensus by two abdominal radiologists (J.W.L. and T.U.K.) who had 20 and 5 years of experience, respectively. One month after TACE, CT measure- The changes in hemostatic plug size and right femoral artery lumen diameter are summarized in Table 2 . Table 3 . No closure failures or VCD-related complications occurred in these patients.
DISCUSSION
In this study, we used ExoSeal VCDs for closing arteriotomy sites. The ExoSeal VCD is a novel, bioabsorbable device which is introduced directly through a vascular sheath. The device deploys a polyglycolic acid plug over the arteriotomy site, using a visually guided deployment mechanism (14) . The 1-month follow-up CT examinations in this study showed eccentric wall thickening with soft-tissue densities at the anterior wall of the CFA, which resembled the bioabsorbable plug. Therefore, the eccentric soft-tissue dense wall thickening was assumed to be the hemostatic plug (15) . We found that the diameters of the puncture site CFA did not differ significantly from the contralateral CFA on the 1-month and final follow-up CT images in both the single and multiple vascular closure groups, which suggests the safety of this VCD. Our results correspond to those of previous studies showing the safety and efficacy of these VCDs (7, 16, 17) . Because the hemostatic plug is attached to the outside of punctured vessel wall (18) , it is assumed that the ExoSeal VCD rarely induced luminal narrowing in the vessel. It is known that the hemostatic plug of the ExoSeal is fully resorbed within 60-90 days (18) , but only 54% of our cases showed a completely resorbed hemostatic plug. The remaining cases demonstrated partial resorption at a mean follow-up duration of 323 days, which was longer than the duration reported in a previous study. In conclusion, follow-up CT images in patients who underwent TACE and vascular closure with an ExoSeal VCD showed no evidence of significant vascular stenosis or significant vessel wall thickening despite repetitive punctures. Therefore, ExoSeal VCD can be used safely to achieve hemostasis after regional oncologic interventional procedures in patients with hepatic malignancy. 

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