Medical devices & diagnostics · Venous disease
InnoVein
A prosthetic valve for the deep veins of the leg, aimed at a disease with no cure and at a device category that has never reached market. Five patients were to receive it in Australia. The public record has not moved since 2021.
A ball in a cage, inside a thigh vein
The drawing in the patent is almost plumbing. An expandable metal frame sits inside the femoral vein. Near its middle there is a seat, above it a retention member, and between them a ball.
Blood heading toward the heart pushes the ball off its seat and flows past. Blood falling back under gravity drives the ball into the seat and stops. That is the whole mechanism, and InnoVein holds three granted US patents on versions of it.
On January 15, 2020, according to the study registration, the first patient was to receive one. Not in San Carlos, where the company was based, and not anywhere in the United States. The listed sites were Hollywood Private Hospital and Sir Charles Gairdner Hospital in Nedlands, Western Australia, and Flinders in Adelaide.
The disease that only gets managed
Chronic venous insufficiency begins when the one way valves inside the leg veins stop closing. Blood pools, pressure rises, ankles swell, skin darkens, and eventually the skin opens into an ulcer that can stay open for years.
The National Science Foundation abstract for InnoVein’s Phase II grant states it in the government’s own words: “Currently, no definitive treatment option exists to address the underlying cause of the disease, valvular reflux, which leaves millions of patients with chronic venous ulcers, skin thickening, and pain for years to decades.” Compression, dressings and ablation of surface veins all treat what the failure produces. None puts a working valve back.
A category with a long record of failing
Replacing a venous valve sounds like replacing a heart valve, and it is not. Veins carry slow, low pressure flow, which is the condition in which artificial surfaces clot. The literature is old and consistent. A 2008 engineering paper reported that “Currently, there are no commercially available prosthetic venous valves as previous efforts have been hampered by late failure and biocompatibility issues”. A 2022 review listed the materials tried, among them platinum, pyrolytic carbon covered titanium and polytetrafluoroethylene, and found that “these concepts failed to meet clinical standards, with occlusion, hyperplasia, fibrosis, and thrombosis among the main drawbacks observed”. Sixteen years after the first paper, a 2024 review still reported that “There is an unmet clinical need, no valve prosthesis is commercially available to date.”
The nearest counterexample is enVVeno Medical’s VenoValve, a bioprosthetic valve that completed a US pivotal trial. On August 20, 2025 the FDA sent enVVeno a not approvable letter, saying the improvement in severity scores was not enough on its own without a hemodynamic measurement correlating with it, and raising concerns about rehospitalizations after the open operation. That is the bar InnoVein’s device would also have to clear.
A mentor, a student, and a catheter that went nowhere
Austin Walker trained as a biomedical engineer at Northwestern and went to the University of California, San Francisco intending to become a surgeon. He spent a year designing a urinary catheter, and the patent landscape killed it. Under the mentorship of Albert K. Chin, who became his cofounder, he turned to veins. Y Combinator lists three founders: Walker as founder and CEO, Al Chin, and Tom Kramer. All three are inventors on the earliest granted patent.
Money in, then quiet
The money arrived early. A Form D filed in July 2018 reported $6,535,535 sold from 55 investors. An amendment three months later raised that to $10,748,933 from 66. The NSF added $225,000 in 2017 and a Phase II award that reached $1,371,596 and ran to March 2023.
Then the tempo changed. A second Form D, filed February 6, 2023 from a new address in Santa Rosa, reported an $11,923,800 offering with only $2,545,164 sold to seven investors. Walker had moved from executive officer to director. A new name, David Hovda, appeared as executive officer and director. Hovda later became CEO of another valve company, Versa Vascular. Y Combinator now lists InnoVein as Inactive.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| Patents | Three US grants name Innovein, Inc. as assignee: US 10,231,838 (granted Mar 19, 2019), US 10,912,647 (granted Feb 9, 2021) and a third granted Jan 31, 2023. Inventors include Albert K. Chin, Austin Walker and Thomas A. Kramer. | Public record |
| Federal grants | NSF SBIR Phase I award 1722221, $225,000, Jul 2017 to Dec 2018, principal investigator Austin Walker. Phase II award 1927074, $1,371,596 obligated, Oct 2019 to Mar 2023, principal investigator Teresa Woodson. Total $1,596,596. | Public record |
| Animal data | A Forbes profile dated January 2017 said “Innovein’s procedure has been validated in lab and animal trials, and human trials are set to start next year.” Implants were registered to begin in January 2020, three years later. No animal study has been published. | Independent |
| Clinical study, as registered | NCT04253301, protocol IM-CP-2001. Single group, estimated enrollment 5, start date Jan 15, 2020 listed as actual. Primary outcome: major adverse events at 30 days. Three Australian sites, none in the United States. | Public record |
| Study status | The registry still reads RECRUITING, last verified September 2021 and last posted September 17, 2021. The estimated primary completion date of Feb 15, 2022 passed with no update. Estimated overall completion is still Jan 15, 2027. | Public record |
| Results | No results posted on ClinicalTrials.gov. No peer reviewed paper by the company found in PubMed as of September 23, 2026, and no coverage found in the vascular trade press. | Not found |
| US regulatory | No FDA 510(k) and no premarket approval on record. No public record found of an investigational device exemption or a breakthrough device designation. | Not found |
| Australian oversight | Trials of unapproved devices in Australia run through the Therapeutic Goods Administration, which says of its notification scheme: “We do not evaluate any data about the clinical trial at the time of notification.” No record found identifies which pathway this study used. | Public record |
| Capital reported | Form D filings report $13,294,097 sold in total. A startup tracker reported in November 2020 that “To-date, the company has raised $6.7M.” That is $4.0 million below what the company told the SEC two years earlier. | Differs from filings |
| Peer recognition | A 2024 survey lists Innovein among the venous valve programs that reached clinical testing, alongside VenoValve and enVVe, citing its patent application and NSF award rather than any clinical publication. | Independent |
Read plainly: InnoVein built real intellectual property, won competitive federal grants twice, raised more than $13 million from accredited investors, and got a device into human beings. What it has never produced in public is a number. No safety result, no reflux measurement, no ulcer healing rate, not even a line saying how many of the five patients were implanted. For a device class whose history is late failure, the absence of follow up data is the finding.
What to watch
- Any update to NCT04253301. The record has been frozen since September 2021 and the listed completion date is January 2027.
- Any publication or conference report of the Australian feasibility results. None has appeared in six years.
- A new Form D. The February 2023 offering left $9,378,636 unsold.
- What the FDA asks for next in this category after the August 2025 not approvable letter for VenoValve.
In their words
“We cure intractable leg wounds with a replacement valve for veins.”
InnoVein company description, Y Combinator startup directory · Company-stated
“Over 10% of the U.S. is affected by poorly functioning valves in the veins of legs and advanced vein disease.”
InnoVein website, 2017 archive · Company-stated
“We are driven by the desire to tackle this massive unmet clinical need and are happy to discuss with all individuals interested in this disease.”
InnoVein contact page, 2015 archive · Company-stated
“Incredible mentors and advisors. I am fortunate to be surrounded by CEOs who have +$100 million in financing and exited multiple medical technology companies, physician thought leaders, regulatory/reimbursement experts, and more.”
Austin Walker, CEO, Medical Device and Diagnostic Industry, 2016 · Interview
“Currently, there are no commercially available prosthetic venous valves as previous efforts have been hampered by late failure and biocompatibility issues”
Oberdier and colleagues, BioMedical Engineering OnLine, 2008 · Peer reviewed
“There is an unmet clinical need, no valve prosthesis is commercially available to date.”
Götz and colleagues, BioMedical Engineering OnLine, 2024 · Peer reviewed
“We are obviously disappointed by the FDA’s decision”
Robert Berman, CEO of enVVeno Medical, in Endovascular Today, August 2025 · Independent
Related companies
Sources
- Public recordClinicalTrials.gov NCT04253301, InnoVein Valve and Delivery System feasibility study
- Public recordForm D and Form D/A, Innovein, Inc., CIK 0001745398
- Public recordForm D, Innovein, Inc., CIK 0001745398
- Public recordNSF SBIR Phase I award 1722221 and Phase II award 1927074
- Public recordPatents assigned to Innovein, Inc., including US 10,231,838 and US 10,912,647
- Public recordClinical Trial Notification scheme guidance
- Peer reviewedThe design, development, and evaluation of a prototypic, prosthetic venous valve
- Peer reviewedBiohybrid elastin-like venous valve with potential for in situ tissue engineering
- Peer reviewedTranscatheter bicuspid venous valve prostheses: fluid mechanical performance testing
- IndependentFDA Issues Not-Approvable Letter for enVVeno’s VenoValve for CVI
- InterviewMedtech’s Rising Stars: Austin Walker
- IndependentAustin Walker profile, 30 Under 30
- IndependentInnovein Medical On The Move
- IndependentMedtech Startups: Venari Medical, Companion Medical, InnoVein
- IndependentMedtronic veteran named CEO of Versa Vascular
- CompanyInnoVein company page and founder list
- CompanyInnoVein website, The Need and Contact Us pages
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
