First-Generation Bioresorbable Stent Performs Well in SFA Lesions

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The first fully bioresorbable stent implanted in human patients shows angiographic results similar to those of permanent metal stents in occlusive lesions of the superficial femoral artery (SFA), according to a multicenter, nonrandomized study appearing online February 12, 2014, in JACC: Cardiovascular Interventions.

Researchers led by Martin Werner, MD, of Park Hospital Leipzig (Leipzig, Germany), prospectively enrolled 30 patients with symptomatic de novo SFA disease, implanting them with Igaki-Tamai (Igaki Medical Planning Company, Kyoto, Japan) bioresorbable stents. The Igaki-Tamai stent is made of biodegradable poly-L-lactic acid (PLLA) that ultimately metabolizes to carbon dioxide and water. The stent is CE mark approved in Europe. Previous studies indicate the stent disappears from human coronary arteries within 3 years.

There is currently 1 fully bioabsorbable DES at an advanced stage of development, the everolimus-eluting PLLA-based BVS stent (Abbott Vascular, Santa Clara, CA), implanted in human patients after the Igaki-Tamai stent.

Results in the 30 patients were comparable to those receiving metal stents through 1 year (table 1). Technical success was 96.7%, and mean diameter stenosis was reduced from 89.9 ± 11.1% to 6.2 ± 12.0%.

Table 1. Outcomes Through 1 Year

At 57 days postprocedure, 1 patient died due to heart failure and pneumonia, though this was adjudicated as not related to the procedure or device. At 12 months, there were 34 serious adverse events, 18 related to the device or procedure, but in all cases of restenosis or reocclusion, it was possible to navigate a guidewire through the obstructed stent without difficulty so that all cases of TLR were successful.

In addition, mean ankle brachial index increased from 0.71 at baseline to 0.89 (± 0.19) at 12 months, improving by more than 0.15 compared with baseline in 15 cases (53.6%). At 6 months, 23 patients (82.1%) had an improved walking capacity compared with baseline, and 20 patients (71.4%) had improved their walking speed. The majority of patients (n = 26; 92.9%) also could climb stairs with less trouble. At 1 year, all patients showed improvements in walking distance compared with baseline capacity. Twenty-four patients (85.7%) also showed improved walking speed and 23 (82.1%) could climb stairs with less trouble

Stent Modifications Still Needed

“Similar to the results in the coronaries, the treatment of symptomatic SFA lesions with the biodegradable Igaki-Tamai stent was safe and effective in achieving favorable acute angiographic results,” the authors conclude. “Functional endpoints. . . , even if affected by a relatively high reintervention rate, were acceptable, showing improvement in most of the patients in walking distance and speed, because of the high secondary patency rate.”

Nevertheless, they acknowledge, “Compared with recently published trials, the Igaki-Tamai stent did not match the patency rates of third-generation nitinol stents,” such as in the RESILIENT trial, which utilized the LifeStent (Bard Peripheral Vascular, Tempe, AZ).

Still, “this study shows that the biodegradable Igaki-Tamai stent can achieve an immediate angiographic result similar to the result of other metal stents,” the authors maintain. “Modifications of stent characteristics (eg, drug-eluting properties) or combination with other treatment modalities (eg atherectomy, drug-coated balloons) are needed to optimize the results, while leaving nothing behind.”

Long-term Durability Questioned

In an accompanying editorial, Barry T. Katzen, MD, of the Baptist Cardiac & Vascular Institute (Miami, FL), notes that “excellent short-term results can be achieved using this PLLA stent,” as confirmed by the high short-term technical success rate. However, the primary patency rate at 12 months is more or less equivalent to angioplasty. In addition, “the restenosis rates … do raise concern about durability and healing long term,” Dr. Katzen cautions.

Overall, while “there is great enthusiasm for biodegradable devices,” Dr. Katzen notes, “this study raises concerns about this device being able to [achieve] sustainable results. . . Although the device is able to achieve satisfactory short-term outcomes, further study and modification will be required to improve outcomes to the expected levels of contemporary self-expanding nitinol stents.”

Study Details

The mean age of patients was 67.7 years and 77% were male. The mean lesion length was 5.9 cm. Target lesions were mainly situated in the mid (46.7%) and distal (40.0%) SFA. Average reference vessel diameter was 5.3 ± 0.4 mm. CV risk factors were highly prevalent, including hypertension (90%), current or former smoking (60%), and diabetes (56.7%).

 

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Sources:
1. Werner M, Micari A, Cioppa A, et al. Evaluation of the biodegradable peripheral Igaki-Tamai stent in the treatment of de novo lesions in the superficial femoral artery: the GAIA study. J Am Coll Cardiol Intv. 2014;Epub ahead of print.

2. Katzen BT. A great start, but the promise of biodegradable stents remains to be proven [editorial]. J Am Coll Cardiol Intv. 2014;Epub ahead of print.

 

Disclosures:

• Dr. Werner reports serving as a consultant for Kyoto Medical.
• Dr. Katzen reports serving on the advisory boards of Boston Scientific, Medtronic Vascular, and WL Gore, and holding the Endowed Chair of Cook Medical.

 

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