Silk Road raises $47M to grow stroke-prevention business

Silk Road will use the money build out its commercial infrastructure in the U.S. while targeting markets overseas. 

Silk Road Medical has raised $47 million to commercialize its stroke-prevention devices in the U.S. and overseas. The funding positions Silk Road to build on approvals and reimbursement nods it has picked up on both sides of the Atlantic for its transcarotid artery revascularization (TCAR) devices. 

New investors Norwest Venture Partners and Janus Capital Management led the round with the support of existing backers Warburg Pincus, The Vertical Group and CRG. Silk Road persuaded the syndicate to invest $47 million less than two years after it tapped some of the same investors for $57 million on the strength of its potential to corner a big, emerging medical device market.

Sunnyvale, California-based Silk Road has built its nascent business upon products that facilitate the TCAR surgical procedure. TCAR is used to treat carotid artery blockages that could cause strokes. The first step is to direct blood flow in the carotid artery away from the brain. Once this is done, surgeons can insert a stent into the carotid artery to stabilize the plaque without putting the brain at risk of fragments that may come loose during the procedure.  

Silk Road’s Enroute product line covers both steps in this process. The Enroute Transcarotid Neuroprotection System takes blood from the carotid artery, filters it and returns it to the body via the leg. While this system is in place, surgeons can insert the Enroute Transcarotid Stent System.

Silk Road has won approvals for the devices on the strength of data linking the system to a 1.4% 30-day all stroke rate. And in doing so has attracted the attention of a growing pool of investors. 

"TCAR is an elegant, patient-friendly approach that has really resonated with physician leaders in the field. I have followed the company and its progress for years and have been pleased to see their rapid FDA approvals and favorable reimbursement decisions,” Norwest Venture Partners’ Robert Mittendorff, M.D. said in a statement.

The challenge now is to turn first-mover status in the transcarotid sector into sales that justify the amount of money investors have pumped into Silk Road. The $47 million investment is intended to support this effort by equipping Silk Road to build out its commercial infrastructure in the U.S. while targeting markets overseas.