Morphology of In-Stent Restenosis Associated With 1-Year Prognosis After Repeat Endovascular Therapy

In a subanalysis of the ZEPHYR study, researchers evaluated characteristics of in-stent restenosis (ISR) after drug-eluting stent (DES) implantation for femoropoplietal lesions.

After repeat endovascular therapy, the morphology of DES-ISR had a significant association with 1-year prognosis, according to findings published in JACC: Cardiovascular Interventions.

While new generation bare-metal nitinol stents (BNS) and DES have improved endovascular therapy outcomes, the incidence of ISR continues to be a problem, particularly during the chronic phase.

The ZEPHYR study (Zilver PTX for the femoral artery and proximal popliteal artery) was a prospective multicenter study that included 210 cases (mean age: 73 ± 9 years; 67% male) with ISR confirmed at 1 year post-DES implantation. DES-ISR was categorized into the following classes: class 1, focal lesions (≤50 mm in length); class II, diffuse lesions (>50 mm in length); and class III, totally occluded ISR.  

Of the 210 cases with ISR, 134 underwent re-endovascular therapy to re-canalize the restenotic lesions. Restenosis was defined as “recurrence of ≥50% diameter stenosis determined by angiography or a peak systolic velocity ratio >2.4 by DUS [duplex ultrasonography].”

Critical limb ischemia occurred at a prevalence of 25% (n=58) and the average lesion length was 18 ± 9 cm. Class II and III lesions had a significantly higher risk of restenosis, compared with class I (74% and 78% vs 53%; P=.048 and .019, respectively). Major adverse limb events were also higher in the class II and III groups (56% and 56% vs 32%; P=.025 and .022, respectively), 1 year following therapy.

Chronic total occlusion and external elastic membrane area size prior to DES implantation were factors associated with DES-ISR morphology (P=.009 and .017). The proportion of classes I, II, and II cases with a loss of patency 1 year after DES implantation were as follows: 50% (n=106), 25% (n=52), and 25% (n=52), respectively.

Among the different DES-ISR classes, the treatment strategy was not significantly different and approximately two-thirds underwent re-endovascular therapy.

After re-endovascular therapy, the incidence of restenosis was estimated at 53% for class I (95% confidence interval [CI]: 39% to 67%), 74% for class II (95% CI: 58% to 90%), and 78% for class III (95% CI: 16% to 94%). Major adverse limb events were observed in 32% of class I cases (95% CI: 20% to 45%), 56% in class II (39% to 73%), and 56% in class III (41% to 72%). Class II and III lesions had significantly higher risks of both restenosis and major adverse limb events (P=.025 and .022, respectively).

“This difference of the ISR-pattern distribution between DES and BNS might lead to a possible superiority of DES to BNS,” researchers noted. “However, because the current study did not directly compare DES to BNS, it remains unrevealed whether DES would be superior to BNS in subsequent treatment for ISR.”

However, based on DES’s reliability and potential to reduce restenosis rates, researchers speculate that the device will continue to be used, and that their findings will help inform clinicians when considering patients for endovascular revascularization.

More studies are necessary to determine the clinical impact of restenotic patterns after DES implantation for femoropopliteal lesions.

Reference

Iida O, Takahara M, Soga Y, et al; on behalf of the ZEPHYR Investigators. The characteristics of in-stent restenosis after druge-eluting stent implantation in femoropoplietal lesions and 1-year prognosis after repeat endovascular therapy for these lesions. JACC Cardiovasc Interv. 2016;9(8):828-834. doi: 10.1016/j.jcin.2016.01.007.