Data Presented on Silk Road Medical's Enroute Neuroprotection System

June 15, 2016—Silk Road Medical, Inc. announced that data for the company’s Enroute transcarotid neuroprotection and stent system were presented at the Society for Vascular Surgery’s 2016 Vascular Annual Meeting held June 8–11 in National Harbor, Maryland. Six presentations on the Enroute system, which is designed and indicated for transcarotid artery revascularization (TCAR), were featured at the meeting.

According to the company, Christopher Kwolek, MD, who is National Coprincipal Investigator for the ROADSTER trial, presented data on TCAR with high-rate flow reversal embolic protection. In this study, the Enroute device demonstrated improved stroke and death rates after US Food and Drug Administration premarket clearance.

Dr. Kwolek presented a 30-day all-stroke rate of 1.3% from the continued access cohort of patients from the ROADSTER trial, which consisted of an additional 78 high-surgical-risk patients enrolled beyond the pivotal cohort of 141 patients while the company’s premarket clearance application was being reviewed by the US Food and Drug Administration. This rate compares to a 30-day all-stroke rate of 1.4% in the pivotal cohort, for a combined rate of 1.4% in 219 patients.

The 30-day stroke and death rates were 2.8%, 1.3%, and 2.3% in the pivotal, continued access, and combined cohorts, respectively. “The combined outcomes in high-surgical-risk patients are remarkably better than high-surgical-risk patients treated with conventional carotid endarterectomy,” commented Dr. Kwolek in the company’s press release. Dr. Kwolek is Director of the Vascular and Endovascular training program at Massachusetts General Hospital in Boston, Massachusetts, and Chief of Vascular Surgery at Newton Wellesley Hospital in Newton, Massachusetts.

Also at the Vascular Annual Meeting, Ignacio Leal, MD, of Complejo Hospitalario de Toledo in Spain, whose site was the leading enroller in the ROADSTER study, presented 1-year follow-up after TCAR with the Enroute transcarotid neuroprotection system. Dr. Leal presented on a cohort of 50 consecutive patients, including those enrolled before and within the ROADSTER trial, and reported no strokes or deaths at 30 days and a 12-month stent patency and stroke-free survival rate of 100%. Dr. Leal concluded, “TCAR can be done with a high rate of technical success, an extremely low rate of major adverse events, and excellent 1-year stroke-free survival and stent patency.”

Silk Road Medical also noted that a poster demonstrating that the temporary reversal of blood flow during TCAR does not change brain electrical activity was presented by Ann Kim, MD, of University Hospitals Case Medical Center in Cleveland, Ohio, on behalf of her colleagues at Case Medical Center, University of California Los Angeles School of Medicine in Los Angeles, California, and State University of New York at Buffalo, New York.

Dr. Kim reported that 28 patients enrolled in the ROADSTER trial underwent electroencephalogram monitoring during TCAR, with nine patients having bilateral carotid artery disease including four of nine with contralateral occlusion. No changes in electroencephalogram or somatosensory evoked potentials or adverse events occurred during the implementation of the ENROUTE NPS device in any patients. Furthermore, none of the patients exhibited changes in their pre- and postintervention neurologic physical exam or their National Institutes of Health stroke scale.

Dr. Kim concluded, “Reversal of flow did not elicit any change in brain electrical activity, even in patients with bilateral carotid disease. This finding, coupled with the unchanged postoperative neurologic exam, suggests that temporary reversal of flow is safe. Carotid stenting performed with carotid artery reversal of blood flow can mitigate carotid embolization without causing brain ischemia."

Vikram Kashyap, MD, who is the Coprincipal National Investigator for the ongoing ROADSTER 2 study, led an Society for Vascular Surgery/European Society of Vascular Surgery joint debate session titled, “During Carotid Artery Stenting, Retrograde Flow is better than Filter-Based Embolic Protection Devices for the Prevention of Embolic Stroke.”

In his presentation, Dr. Kashyap commented, “The very nature of TCAR and its direct carotid approach significantly reduces the risk of stroke, since it does not require embolegenic steps like traversing the aortic arch and the carotid lesion with wires and catheters before implementing neuroprotection. It is simply a more logical approach.” Dr. Kashyap is Professor and Chief, Division of Vascular Surgery, at University Hospitals Case Medical Center in Cleveland, Ohio.

Also a Vascular Live presentation titled, “TransCarotid Artery Revascularization (TCAR): The Way Forward in Treating Carotid Artery Disease and Stroke Prevention,” featured Drs. Kashyap, Raghu Motaganahalli, and Peter Schneider.

Dr. Motaganahalli is Associate Professor at Indiana University in Indianapolis, Indiana. Dr. Schneider, who serves as Coprincipal National Investigator of the ongoing ROADSTER 2 postapproval study, is Chief of the Division of Vascular Therapy at Kaiser Foundation Hospital in Honolulu, Hawaii.

During the session Dr. Schneider commented, “ROADSTER 2 is enrolling faster than we anticipated in a broad group of centers including many sites where TCAR has just recently been adopted. There is a high level of enthusiasm for the procedure and this experience will build upon the compelling evidence base from ROADSTER 1.” Dr. Schneider and Dr. Kashyap also led a pre-course education session titled, “How to Make Carotid Stenting Competitive with Carotid Endarterectomy" that featured TCAR and the Enroute system, reported Silk Road Medical.