Management of Iliac Stent Embolization During Transfemoral Transcatheter Aortic Valve Replacement

Abstract

Transcatheter aortic valve replacement (TAVR) using stent-based bio-prostheses has recently emerged as an alternative to surgical valve replacement in selected high-risk patients. The main route for TAVR is a percutaneous approach from the femoral artery using large-bore sheaths (16-24 Fr). Vascular access complications are a clinically relevant issue in TAVR procedures and are reported to occur in up to one quarter of these patients. Here we discuss a case of iliac stent embolization as a complication and its management with the use of percutaneous techniques.

Case report

In preparation for a transcatheter aortic valve replacement (TAVR) via left femoral artery access, an 82-year-old male with known history of peripheral arterial disease with left common iliac artery stenosis underwent intervention one month prior. The patient received a 7mm x 30mm Cobalt (Medtronic) balloon-expandable stent that was post-dilated with a Mustang 9mm x 20mm balloon (Boston Scientific). The patient had a CT angiogram that showed his external iliac artery diameter to be 5.8mm on the right and 6.0mm on the left. It was therefore recommended to utilize the left side for access for TAVR. Access was obtained in bilateral common femoral arteries. Intravascular ultrasound (IVUS) (Volcano Corporation) imaging of the left common iliac artery stent was performed, which revealed an average luminal diameter of 8.8mm with a minimal lumen diameter of 8.3mm (Figure 1). Balloon angioplasty of the left common iliac artery stent was performed using a Mustang 9.0mm x 40mm balloon with good expansion. After reviewing the imaging, the left iliofemoral artery segment was deemed feasible for a percutaneous approach to TAVR.  

Serial dilators went through the iliac stent without difficulty into the descending aorta.  However, as the expandable 18-French Edwards delivery sheath (Edwards Lifesciences) was advanced up to the common iliac artery, it deformed the common iliac artery stent longitudinally, as shown on fluoroscopy. The delivery system was removed and further dilation of the common iliac stent was performed using a Mustang 10mm x 40mm balloon. Nevertheless, the delivery system was unable to advance past the stented segment in the iliac artery without further damaging the iliac stent. At this point, a SoloPath (Terumo) 21-French sheath was placed and gradually dilated to its maximal sheath diameter. Once in place, aortic valve balloon valvuloplasty using an Edwards 23mm x 40mm balloon was performed with good expansion. The Edwards 26mm valve delivery sheath was then advanced through the SoloPath Sheath, but completely dislodged the left common iliac artery stent, embolizing it around the delivery sheath.  However, since the stent was in a stable position on the delivery sheath without movement, the valve was advanced and positioned across the aortic valve for deployment. TAVR was performed successfully, while the embolized iliac stent remained around the delivery sheath (Figure 2). Subsequent transesophageal echocardiography images revealed an excellent result with only trace paravalvular leak.  

Upon retrieval of the delivery system, the common iliac stent was then slowly positioned in the distal descending aorta and deployed using the valve balloon (Figure 3). An iCAST 10mm x 38mm covered stent (Atrium Medical) was deployed in the distal aorta to exclude the deformed deployed stent. This stent was then crossed from the contralateral side and the stent post-dilated using simultaneous kissing technique from bilateral aorto-iliac arteries using two Mustang 10mm x 40mm balloons with good expansion. A subsequent aortogram revealed excellent angiographic result through the distal aorta (Figure 4). A new Cobalt 9mm x 40mm balloon-expandable bare metal stent was then deployed in the left common iliac artery with good expansion. Final angiogram revealed no dissection or extravasation with fully expanded and apposed stents (Figure 5). The SoloPath sheath was removed and access site hemostasis achieved using the Prostar suture-closure device (Abbott Vascular). The patient was monitored in the ICU and discharged home 48 hours later.

Discussion

In percutaneous TAVR trials, there is almost a three-fold increased risk of mortality resulting directly from vascular access complications. Some studies have demonstrated that Prostar failure accounts for up to half of all vascular events following TAVR, with the operator learning curve and inappropriate patient selection strongly implicated.¹ Problems in vascular access can occur when sheaths are moved perpendicular to the calcium, as well as from the act of pushing large-caliber catheters and devices through the artery and subsequently pulling them back out again, resulting in a shearing effect to the vasculature. There are three points at which damage takes place in vascular access: 1) gaining access; 2) advancing catheters and devices in and out multiple times; and 3) sheath removal.¹ 

The SoloPath sheath minimizes risk during these periods, because the operator inflates the sheath to improve access and then shrinks it back down again to pull it out. The sheath is inserted in its unexpanded state with an outer diameter of only 4.3mm, facilitating delivery through difficult and tortuous anatomy. A balloon is then inflated to expand the sheath and reach the intended diameter (18 French to 21 French). After completion of the procedure, the sheath can be deflated, enabling low-resistance removal.^2,3 The SoloPath sheath is a feasible alternative to conventional sheaths for transfemoral TAVR patients with advanced atherosclerotic disease or an arterial diameter ≤7mm.⁴ The available expandable sheath for the Edwards Sapien XT valve (eSheath 16-18 French) facilitates expansion for valve passage, and returns to a reduced profile once the valve has passed, limiting vascular trauma.⁵  

Herein, we describe a case where the Edwards eSheath did not allow safe passage of the valve delivery system through the iliac stent, resulting in the embolization of the stent and its subsequent stabilization using a SoloPath sheath and deployment of the embolized stent in the descending aorta.

References

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*Dr. Jon C. George is now Cath Lab Director, Einstein Medical Center, Philadelphia, Pennsylvania.

Disclosure: Drs. Doshi, Kovach, and Varghese report no conflicts of interest regarding the content herein. Dr. George reports he is a consultant for Abbott, Atrium/Maquet, Boston Scientific, Edwards, and Medtronic.

The authors can be contacted via Dr. Jon George at jcgeorgemd@gmail.com.