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In many patients with superficial femoral artery (SFA) disease, implantation of a self-expanding nitinol stent is safe and yields favorable acute and 1-year results, according to an observational study published in the August 2014 issue of the Journal of Endovascular Therapy. However, those with longer lesions are more likely than other patients to need target lesion revascularization (TLR) within that time frame.

Acute technical success was achieved in all but 8 lesions (99.2%). Periprocedural complications (5.4%) were minor, with no deaths, acute amputations, or conversions to vascular surgery.

One-year clinical follow-up was complete in 789 patients (79.1%), with duplex ultrasound imaging available in 754. Clinically driven TLR (primary endpoint) was performed in 17.2% of patients. 

Female Sex, Longer Lesions Predict Revascularization

At 12 months, restenosis occurred in 23.7% of lesions and reocclusion in 10%. The incidence of restenosis/reocclusion was associated with lesion length: 21.7% for lesions up to 10 cm vs 34.7% for intermediate (10-20 cm) and 51.2% for long (> 20 cm) lesions (P for trend < .001). Moreover, the restenosis/reocclusion rate was 39.5% for occlusions vs 21.8% for stenoses (P < .001). In addition, restenoses/reocclusions occurred more often in the left leg than in the right leg (37.5% vs 28.9%; P = .021).

On multivariable analysis, female sex predicted lower rates of TLR at 12 months (OR 0.5; 95% CI 0.3-0.7), while lesion length greater than 20 cm (OR 2.7 vs 10 cm; 95% CI 1.1-6.6) or between 10 and 20 cm (OR 1.9 vs 10 cm; 95% CI 1.0-4.1) predicted higher rates.

At 12 months, Rutherford class, mean ankle-brachial index, and mean walking distance all were improved over baseline (table 1).

Table 1. Changes in Clinical Outcomes at 1 Year

Among the 524 patients assessed with biplanar radiography, 9.4% had a stent fracture; restenosis/reocclusion rates were not significantly increased in this cohort compared with the overall study population (P > .05).

During follow-up, 14 patients died and 4 had an amputation due to preexisting gangrene; no death or amputation was related to the index procedure.

The finding that about one-third of patients experienced restenosis/reocclusion within 1 year is consistent with results from other nitinol stent trials, the authors say. Interestingly, they note, the higher restenosis/reocclusion rate in occluded compared with stenosed lesions did not result from more frequent residual restenoses in the former, as others have suggested. Instead, the difference may be due in part to the longer average stented length of occluded compared with stenosed lesions (16.4 cm vs 7.5 cm), they add.

Previous studies of the impact of sex on restenosis have been inconsistent, the investigators say, with some speculating that vessel diameter or baseline disease may play a role in women’s risk. However, they note, no causal connection between female sex and SFA restenosis has been established, and further investigation is required.

In addition to the observational nature of the study, Dr. Krankenberg and colleagues say its focus on a single technology and the loss of almost one-fifth of patients to follow-up over 12 months are important limitations.

Not Quite ‘Real World’

In an accompanying editorial, Mark G. Davies, MD, PhD, MBA, of Houston Methodist Hospital (Houston, TX), notes that registry patients were primarily from 3 centers, weakening the authors’ claim that the study population is ‘real world.’

Moreover, Ehrin J. Armstrong, MD, of the University of Colorado Denver School of Medicine (Denver, CO), observes that the lesion lengths are relatively short and very few had severe calcification.

“These lesions are less complex than [those of] most real-world patients, but also reflect the available data for anatomic subsets where stenting has proven beneficial,” he told TCTMD in an email communication. “Currently, endovascular treatment of SFA lesions longer than [20 cm] may not provide sustained clinical benefit in the majority of claudicants. However, we need more data in these more complex patient subgroups, [because] stent technology continues to evolve.”

In fact, Dr. Davies says, the findings demonstrate that “outside a clinical trial the best results are achieved when the original inclusion criteria are used and the [indications for use] are clearly followed. The results reflect the established paradigms in SFA disease.”

Stent Fracture Has Been Reduced

Dr. Armstrong commented that the stent fracture incidence of 9.4% is much higher than expected based on recent registry studies with newer-generation nitinol stents, adding that the data are difficult to interpret due to the variable follow-up and possible selection bias in follow-up radiography. Nonetheless, he said, contrary to the current results, “prior studies have definitively shown that fracture is associated with restenosis.”

Moreover, the improvement observed in walking distance, while impressive, “still represents poor functional capacity,” Dr. Davies says, adding that measures to improve patients’ overall health, such as education on smoking cessation and prescription of statins, are needed to enhance functionality.

Finally, Dr. Davies advises that in an era of reduced healthcare resources, physicians “must weigh the benefit of best medical therapy over any intervention for claudication, especially in those with Rutherford category 1 or 2 disease.”

1. Krankenberg H, Tübler T, Sixt S, et al. German multicenter real-world registry of stenting for superficial femoral artery disease: clinical results and predictive factors for revascularization. J Endovasc Ther. 2014;21:463-471.

2. Davies MG. Newer generation stent delivers good 1-year functional outcome in patients with SFA disease [editorial]. J Endovasc Ther. 2014;21:472-473.

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