In-Stent Restenosis After Femoropopliteal Interventions With Drug-Eluting Stents: Same But Different?

SEE PAGE 828 T he superficial femoral artery (SFA), the longest artery in the human body, is subjected to nearly constant torsion, bending, and compression. It is perhaps natural to expect it to be the Achilles heel of endovascular interventions, plagued by higher rates of in-stent restenosis (ISR) compared to other arterial beds. Indeed, the 12-month rates of ISR after implantation of modern bare metal nitinol stents in the SFA and proximal popliteal artery range from 18% to 37% (1–6). The variation in rates of ISR depend in part on the patient and lesion characteristics and on the particular ultrasonographic criteria used to define the binary restenosis of 50% diameter reduction. The advent of drug-eluting stent (DES) technology created optimism that rates of ISR could be reduced but ultimately led to disappointment after sirolimus-eluting stents were found to be no better than bare metal stents (BMS) (7). The introduction of paclitaxel-eluting selfexpanding stents a decade later reignited the hope of reducing ISR rates. In the randomized Zilver PTX study, restenosis was conservatively defined as a peak systolic velocity ratio >2 on duplex ultrasound and occurred in 17% of patients after 12 months of follow up (8). The study population was carefully selected and included 9% of patients with critical limb ischemia, short lesions (mean lesion length 66 39 mm) and excluded cases of in stent restenosis. The fact that similar rates of restenosis were found in a more challenging patient population studied in the Zilver PTX Global Registry is very