Angiographic and Intravascular Imaging Findings for Ultrasound Detected Aneurysmal Degeneration Following Polymer Based Paclitaxel Eluting Nitinol Stent Implantation for Femoropopliteal Artery Occlusion

The Eluvia (Boston Scientific, Arden Hills, MN, USA) polymer based paclitaxel eluting nitinol stents (PB-PESs) showed favourable durability in the latest clinical trials. However, aneurysmal degeneration (AD) was identified by duplex ultrasound (DUS) after PB-PES implantation.¹ The long term impact of AD remains unclear.

An elderly man in his eighties, with a history of endovascular therapy (EVT) for right superficial femoral artery (SFA) and proximal popliteal artery (PPA) occlusion, underwent follow up DUS three months after the procedure. To avoid the oversized ballooning and tenting, the device sizes were chosen based on the external elastic membrane diameter (7.0 mm in SFA and 6.5 mm in PPA), which was evaluated by intravascular ultrasound (IVUS). Pre-dilatation was performed with a 6.0 mm non-compliant balloon. Two 7.0 × 120 mm PB-PESs were implanted in the SFA; similarly, 5.5 × 80 mm SUPERA (Abbot Vascular, Lake Buff, IL, USA), a bare nitinol interwoven stent (IWS), was implanted in the PPA (Fig. 1A). A drug coated balloon was not used at any stage of this endovascular treatment. DUS revealed AD around the PB-PES (Fig. 1B, C). No blood flow was identified outside the stent (Fig. 1E, F). However, no AD was observed around the IWS (Fig. 1D, G). Follow up angiography, IVUS, optical frequency domain imaging (OFDI), and angioscopy were performed.

Fig. 1.

Aneurysmal degeneration (AD) after polymer based paclitaxel eluting nitinol stent (PB-PES) implantation. Two 7.0 × 120 mm PB-PESs and a 5.5 × 80 mm interwoven stent (IWS) were implanted for right femoropopliteal artery occlusion (A). AD can be observed around the PB-PES (B,C). No blood flow can be seen outside the stent (E,F).

Follow up angiography findings are shown in Fig. 2A. No stent malapposition was observed at the PB-PES site. IVUS also showed no stent malapposition around the PB-PES (Fig. 2H, I). OFDI (Fig. 2E, F) and angioscopy (Fig. 2B, C) revealed findings similar to those observed for coronary drug eluting stents. At the IWS site, there was no aneurysmal change, and a thicker neointima was observed (Fig. 2D, G, and J).

Fig. 2.

Imaging findings for aneurysmal degeneration (AD) after PB-PES implantation. Angiography shows no aneurysm formation around the polymer based paclitaxel eluting nitinol stent (PB-PES) site (A). Optical frequency domain imaging (OFDI) (E,F) and angioscopy (B,C) showed coronary drug eluting stent like epithelialisation without aneurysm formation at the PB-PES site. At the interwoven stent (IWS) site, a relatively thicker neointima can be observed on angiography (A), intravascular ultrasound (J), OFDI (G), and angioscopy (D).

This is the first report of angiographic and intravascular imaging findings for AD following PB-PES implantation. Although the cause of AD could not be identified, it may be that AD does not cause the stent malapposition, which carries a risk of stent thrombosis (ST). After the PB-PES implantation, even though AD was observed, stent apposition and epithelialisation seemed almost perfect. AD itself may not be a risk of ST. These findings are relatively different from conventional aneurysmal change after EVT. Therefore, it is proposed that this finding is called the “Halo sign”.

Transparency declaration

Tatsuya Nakama is a consultant at Boston Scientific, Medtronic and Century Medical (Distributer of SUPERA in Japan).

Funding

None.