Biotronik Studies Investigate Efficacy of Minimizing Metal Burden in SFA Therapy

September 18, 2017—Biotronik announced that data from various Biotronik studies demonstrating that reducing metal burden in superficial femoral artery (SFA) therapy could effectively reduce restenosis rates were presented at CIRSE 2017, the annual congress of the Cardiovascular and Interventional Radiological Society of Europe held September 16–20 in Copenhagen, Denmark.

As summarized by the company, Jos van den Berg, MD, chaired a session on reducing metal burden that centered on clinical options to treat SFA lesions with reduced or no metal burden. The symposium included a presentation of clinical results from an extensive “drug-coated balloon (DCB) only” registry, as well as studies focusing on the combined use of DCBs and a low chronic outward force (COF) stent. The session also covered the clinical impact of COF in nitinol stents.

Martin Funovics, MD, presented preclinical data on the use of low COF versus high COF stents, which was supplemented by the interim results of the BIOFLEX COF randomized controlled trial that established that lower COF results in lower restenosis rates. This could be pivotal in changing the way physicians plan treatment of SFA disease when implanting self-expanding stents.

According to Biotronik, the innovative methodology of evaluating efficacy using “normalized, cumulative percent restenosis” offers, for the first time, an accurate way to systematically assess restenosis with a higher sensitivity and specificity than the traditional Doppler ultrasound method.

Claus Nolte-Ernsting, MD, presented the all-comers stenting registry BIOFLEX PEACE, which investigated the Pulsar-18 stent. The registry demonstrated that in a real-world setting, physicians are aware of the higher COF/higher restenosis link. This is a shift from the established 1 to 2 mm that has been followed in the last decade. Reducing stent oversizing is a simple method to reduce the COF of the implanted stent. A primary patency rate of 86.2% and a freedom from target lesion revascularization rate of 97.1% despite a lesion length of 11.6 cm appear to indicate improved outcomes.

Gunnar Tepe, MD, presented results from the Passeo-18 Lux all-comers registry, BIOLUX P-III. The registry enrolled more than 700 patients with SFA lesions. The results demonstrated a primary patency rate of 84.9% and freedom from target lesion revascularization rate of 94.5% clearly indicate the success of the Passeo-18 Lux. Despite the high moderate/severe calcification rates of 41.7% in lesions with an average length of 9.4 cm, the bailout stenting rate was only 20%.

BIOLUX 4EVER, which is designed to challenge the need for an SFA drug-eluting stent (DES), investigated the use of full-lesion coverage with a DCB followed by a bare-metal stent (BMS). Koen Deloose, MD, presented data showing the Passeo-18 Lux and Pulsar-18 study devices generated a primary patency rate of 89.9% at 12 months in average lesion lengths of 8.3 cm. At the 24-month follow-up, primary patency was numerically higher with the DCB and BMS than with the DES. Although these were the interim results from 85 of 120 patients, the primary patency of 84.1% reported compares favorably to reported DES results of 78.2% and 74.8%.

Exploring how to translate all the presented data into clinical practice, Ralf Langhoff, MD, shared a treatment strategy algorithm based on clinically available evidence on the Passeo-18 Lux DCB, the Pulsar-18 BMS, and the combined use of both. By starting treatment with the Passeo-18 Lux device, the physician can decide whether the lesion also needs to be stented based on the response to the DCB. To test this algorithm, he further proposed an outline for a trial.

In Biotronik's press release, Dr. van den Berg concluded, “The emergence of DCBs has revolutionized SFA intervention by eliminating or reducing the need for permanent metallic implants. However, adjunctive stents are still required to scaffold the vessel wall.” He explained, “As the presence and amount of metal may contribute to inflammatory response, potentially leading to restenosis, it seems logical that using thin-strut, low COF stents such as Pulsar is one way to reduce the metal burden.”

He stated further, “Adopting a reactive approach gives us the opportunity to reduce metal burden by only implanting the stent length that’s needed while benefiting from the antiproliferative effect of DCBs. This versatility is, for example, not possible with DES.”