Balloon with microneedle creates drug-eluting reservoir to prevent restenosis

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Patrice Bergeron, Hôpital Privé Residence du Parc, Marseille, France, presented initial results of a new device used in the treatment of peripheral arterial disease at the Multidisciplinary European Endovascular Therapy (MEET) Congress (9–11 June 2013, Rome, Italy). The new balloon deploys a microneedle into the adventitia and diffuses anti-inflammatory drug into the arterial wall.

Bergeron told delegates at the congress that the physiopathology of restenosis includes injury, inflammation and cell recruitment, resulting in intimal hyperplasia, media proliferation and adventitial neovascularisation and fibrosis. The hypothesis behind this technology is that stopping inflammation and neovascularisation from adventitia prevents restenosis.

The Bullfrog drug-delivery catheter (Mercator MedSystems) is a micro-infusion catheter containing a microneedle of 130-micron diameter and 0.9mm length. It allows clinicians to pinpoint the delivery of drugs and biologics deep into the body to treat the root cause of disease. The balloon deploys a microneedle into the adventitia, where the drugs are diffused to bathe the entire vessel cylindrically, from the outside to the inside, creating a unique, tissue-based, drug-eluting reservoir.

The device used dexamethasone, which is a well known and widely available anti-inflammatory drug. “Inflammation begins the restenosis cascade, and dexamethasone reduces inflammation and remodelling proteins, including MCP-1, CRP, TNFα, GM-CSF and MMP-9,” said Bergeron.

He explained that the procedure, using Bullfrog, includes percutaneous device placement over the wire and balloon inflation, followed by subadventitial injections of dexamethasone plus contrast (1cc) every 3cm. This is then followed by subintimal diffusion and balloon angioplasty and/or stenting.

The DANCE (Dexamethasone infusion to the adventitia to enhance clinical efficacy after femoropopliteal revascularization) pilot study is an open-label, non-randomised, single-arm, single-centre clinical feasibility evaluation of adventitial dexamethasone after peripheral arterial disease intervention. The objective was to evaluate technical success, safety and effectiveness outcomes of adventitial dexamethasone delivery by the Bullfrog catheter. The principal investigator is Christopher D Owens, University of California San Francisco, USA.

Twenty patients with superficial femoral artery or popliteal lesions were enrolled in the study between February 2011 and September 2012 at San Francisco VA Medical Center. The mean age was 66±10 years, 100% were men, 55% were diabetic, 95% suffered from hypertension and 100% had hyperlipidaemia. Most of patients (16) had Rutherford class 2 and 3. In the TASC II classification, three patients had type A lesions, nine had type B, seven had type C and one patients presented with type D lesion. Half of the patients had occluded arteries, and the mean lesion length was 8.9±5.3cm.

All patients underwent angioplasty, and three of them also underwent atherectomy. Six of the patients had provisional stents placed.

The haemodynamic and clinical results showed that ankle brachial index improved on discharge, at six months and at 12 months (n=10). The patients treated with the device also had an improvement on Rutherford scores. Six-month patency rates were comparable to results of drug-eluting stents and drug-eluting balloons for longer lesions, Bergeron said.

“Subadventitial injection of dexamethasone seems promising in reducing restenosis at six months. The Bullfrog device is safe and reliable, and is showing good results in US and European trials,” he noted.

The Bullfrog device received the CE mark in February. It had previously received 510(k) clearance from the FDA. In a press release distributed by Mercato after the granting of the CE mark, Owens commented: “The Bullfrog catheter has demonstrated its ability to efficiently deliver potent therapeutic agents outside the blood vessel, specifically to the adventitia. I believe we are now seeing the promise of adventitial delivery: a biologic effect of the drug interrupting the inflammatory cascade that normally leads to restenosis after a vascular intervention.”

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