Four to six percent of patients after endovascular aneurysm repair (EVAR) develop type I endoleak that leaks at either the proximal or distal sealing zone. Type I endoleak of the distal sealing zone (type I_b endoleak) should be treated during or after EVAR [1-3]. If endoleak is expected before EVAR, embolization of the internal iliac artery with limb extension to the external iliac artery, bypass or transposition of the internal iliac artery to the external iliac artery, or iliac bifurcated endograft has been used before or during EVAR. At least, one internal iliac artery should be saved during treatment [2]. We report type I_b endoleak, which was found and successfully treated with a Palmaz XL stent (Cordis, Miami lakes, FL, USA) during EVAR from our experience.

An 86-year-old woman presented with vague abdominal pain. She had been bed ridden for 5 years due to lumbar compression fractures. Though she had no history of ischemic heart disease, a Thallium scan showed reversible ischemia. Computed tomography (CT) revealed aneurysms in the abdominal aorta and right internal iliac artery measuring 66 mm and 40 mm in diameter (Fig. 1B, D). CT showed that the aortic neck was 24 mm in diameter, 20 mm in length and angulated by 80 degrees (Fig. 1A). The right iliac artery was aneurysmal measuring 24 mm in diameter and the left common iliac artery was 22 mm in diameter (Fig. 1C). There was thrombus in the abdominal aortic aneurysm. The patient underwent embolization of the right internal iliac artery with 22 mm Amplatzer vascular plug (AGA Medical, Plymouth, MN, USA) to control type II endoleak from the right internal iliac artery. EVAR was performed one week later. Under general anesthesia, both femoral arteries were exposed by cutdown technique. Three Zenith endografts (Cook Medical, Bloomington, IN, USA) were deployed: 28 mm of the main body through the right side, 24 mm left of the contralateral limb in the left common iliac artery, and 10 mm right of the ipsilateral limb extending to the right external iliac artery. The angiogram after EVAR showed persistent type I_b endoleak in the left common iliac artery even after touch ballooning with Coda balloon (Cook Medical) (Fig. 2A). Balloon-expandable stent, Palmaz XL was deployed (Fig. 2B) and the type I_b endoleak in the left common iliac artery (Fig. 2C) was under control. The Palmaz XL stent was manually mounted with 16 mm Maxi Balloon (Cordis). After deployment of the Palmaz XL stent, it was ballooned again with a Coda balloon. Follow-up angiogram after completion showed no endoleak. The patient was discharged without complications. Follow-up CT in 1 month showed no endoleak (Fig. 3).

When type I_b endoleak is expected before EVAR because of the iliac artery pathology, additional stent graft cuff deployment, embolization of the internal iliac artery with limb extension to the external iliac artery, transposition or bypass of the internal iliac artery to the external iliac artery, or iliac bifurcated endograft may be considered as good alternatives [1,2]. However, treatment modality for type I_b endoleak after EVAR is especially limited, or patients with high risk and those who already have had embolization of the contralateral internal iliac artery.

Type I_b endoleak found at the time of the initial implantation can be managed either by balloon dilatation or placing an additional endograft across leaking graft junctions, or may require extension of endograft distally in order to obtain a complete seal [3,4]. The balloon angioplasty did not seal the endoleak, and we think that the cause of this endoleak was inadequate radial force of an endograft limb in the left common iliac artery. Flare type stent can be another option, but at the time of this case that stent was not available in Korea. So, we used Palmaz XL balloon-expandable stent, which has strong radial force and provides a stronger and more persistent seal.

Arthurs et al. [5] recently reported that aortic neck reinforcement with Palmaz XL stent was still effective in long-term follow-up when used for type I_a endoleak of aortic neck. Malposition of a hand-mounted balloon-expandable stent during deployment is not an unusual complication [6,7]. To prevent malposition and increase the accuracy of stent deployment, the following techniques can be beneficial [6,7]. First, the sheath provides a means to control the sequence of the balloon expansion, and consequently, stent deployment. The portion of the balloonstent apparatus expanding against the overlying sheath also sandwiches the stent between the two providing additional stability. Second, the off-centered loading of the stent onto the balloon leaves a larger portion of the proximal (cranial) balloon exposed when the sheath is partially drawn back. This allows for full expansion of only the proximal portion of the balloon, which prevents proximal stent migration. Again, the distal (caudal) sheath prevents any distal stent migration.

Other methods to reduce maldeployment include using a shorter stent and pre-expanding the proximal and distal end of the balloon prior to placement within the sheath. The partially inflated ends trap the stent and reduce the tendency for one end to unevenly inflate causing "watermelon seeding." The drawbacks of this method include compromised stent length and possible difficulty in inserting the partially deployed balloon and stent past the proximal valve of the sheath [8].

This stent is the hand-mounted balloon-expandable stent, which requires experience in use. And it costs 920,000 Won (Korean currency) in Korea which means additional cost. But, recent data shows long-term stability after deployment during EVAR [5] and this seems to expand indications of EVAR in clinical practices with good results.

In conclusion, we think that Palmaz XL balloon-expandable stent provides strong radial force and a more persistent seal and can be an alternative option to achieve tight sealing and control of type I_b endoleak.