Novel Carotid Artery Revascularization Approach Yields Unprecedented Pivotal Data

Silk Road Medical, Inc. has followed up clinical data presented at the VIVA congress a few weeks ago, with another appearance, this time at the Veith Symposium in New York. 30 day outcomes from the ROADSTER IDE Study point to 1.4% 30 day stroke rate, the lowest seen to date of any contemporary prospective trial of carotid angioplasty and stenting (CAS).

Background

Celebrating its 60th anniversary in 2013, carotid endarterectomy (CEA) has been the “Gold Standard” in carotid artery revascularization because of the low stroke and death rates in multiple prospective trials. Yet CEA is not free of the potential for certain local and systemic complications such as cranial nerve injury and myocardial infarction.

Fifteen years ago transfemoral CAS was introduced with much initial excitement due to the minimally invasive, endovascular advantage, but fell out of favour due to the excess risk of peri-procedural stroke compared to CEA: In a standard surgical risk population, the CREST trial demonstrated peri-procedural strokes occur twice as often in transfemoral CAS patients.

Along came Silk Road Medical’s ENROUTE™ Transcarotid Neuroprotection System (NPS), designed to provide direct access to the carotid artery and reduce the risk of stroke during CAS by diverting dangerous debris away from the brain with a surgically-inspired mechanism to temporarily reverse blood flow. Clever stuff, resulting in a short, minimally invasive and theoretically safe procedure…so how do the numbers add up?

Data from the ROADSTER IDE study using the ENROUTE system, were presented at the Late Breaking Clinical Trials Session at the 2014 Vascular InterVentional Advances (VIVA) Meeting in Las Vegas, with additional data presented at the Veith Symposium in New York, NY.

ROADSTER was a prospective, multi-center, IDE study designed to evaluate the safety and effectiveness of the ENROUTE Transcarotid NPS in a hybrid procedure combining the best elements of CEA and CAS.

Richard Cambria, MD and Christopher Kwolek, MD of Massachusetts General Hospital served as the trial National Co-Principal Investigators. Patients were enrolled at 15 vascular surgery sites, one neurosurgery site, and two multi-specialty sites. The primary endpoint was a composite of Any Stroke (S), Death (D), or Myocardial Infarction (MI) through 30 days.

The trial involved 208 patients in total, with the first 67 classified as “lead-in”, and 141 documented as pivotal. Symptomatic and asymptomatic patients who were at high risk for complications from CEA were enrolled and FDA-approved carotid stent systems were delivered through the direct carotid access point under high rate flow reversal afforded by the ENROUTE Transcarotid NPS. 

Results at 30 days in the Intention to Treat population showed an all stroke rate of 1.4%, which investigators say compares well with documented stroke incidence in traditional carotid endarterectomy procedures. 

Investigator comments 

“These stroke rates in a high surgical risk population are the lowest to date for CAS and comparable to the peri-procedural rates in the standard surgical risk CEA arm of CREST (2.3%). The Silk Road procedure is less of an operation for the patient than a traditional CEA and can be performed in under an hour with local anesthesia. With more experience and evidence, vascular specialists can look forward to incorporating this procedure as a true alternative to CEA for patients,” commented Dr. Cambria.

Company comments

Erica Rogers, CEO for Silk Road Medical, commented, “The ROADSTER data support our hypotheses that led to this device design and procedure. It’s all about stroke. Doctors perform these procedures to reduce the risk of stroke, not to cause a stroke. The ENROUTE transcarotid platform finally delivers a less invasive alternative with the neuroprotection you would expect from a CEA procedure.”

Regulatory status

The ENROUTE NPS and Stent Systems are limited by United States law to investigational use; the ENROUTE Transcarotid NPS has been submitted for 510(k) review and the ROADSTER trial also supports the pending Premarket Approval PMA for the ENROUTE Transcarotid Stent System. The ENROUTE Transcarotid NPS and the ENROUTE Transcarotid Stent System have been granted CE Mark.

Source: Silk Road Medical, Inc., PR Newswire

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