NYA FOUNDER SPOTLIGHT ‒ JOHN SLUMP, ATRAVERSE MEDICAL CEO & CO-FOUNDER
Atraverse Medical CEO & Co-Founder John Slump is a serial medical device entrepreneur with several successful exits, including Surgical Innovation Associates (SIA) where he previously served as CFO. New York Angels (NYA) Members invested in multiple rounds with SIA. Now in his first CEO role, John secured initial seed investment plus additional follow-on investment from NYA Members in every subsequent round offered by Atraverse, the medical device company pioneering next-generation left-heart access and optimized RF technology. John shares how he pitched to New York Angels multiple times, how NYA’s investment process is in the “Goldilocks” zone, and why fundraising is a team sport.
How did you first connect with New York Angels?
I started my first medical device company in my early 20s, and frankly, medical device startup companies are all that I have ever known or experienced professionally. Over the years, I applied for funding from New York Angels with several different companies. My first experience with NYA as a portfolio company was when they invested in Surgical Innovation Associates (SIA), a women’s health company commercializing an implantable device for breast cancer patients undergoing mastectomy and reconstruction.
At SIA, I was a recruited CFO and employee #3 joining Founding CEO Dr. Alexei Mlodinow and Co-Founder/COO Todd Cruikshank. Together, we scaled the company from 3 to approximately 30 employees, grew from $0 to nearly $10 million in revenue, and ultimately consummated a successful acquisition with Integra Lifesciences. With SIA, NYA Members participated across various rounds.
Now in my first CEO role with Atraverse Medical, we are grateful to have garnered investment from NYA Members, many of whom invested in our inaugural seed round in 2023, along with other top-tier angel investment groups across the country. We are pleased that NYA members have reinvested in every single round that we’ve offered since.
Even though you did not initially secure funding from NYA, why did you continue to pitch to NYA with other companies?
New York Angels has maintained a top pedigree and strong reputation in the early-stage startup world over decades. Even when NYA Members did not invest in my prior companies, they always gave me clear feedback. I continued applying to NYA because of their outstanding reputation, deal flow, and the outsized capital they deploy. NYA punches above their weight for an angel group, and I knew it would be worth the persistence.
What was the fundraising process like for Atraverse?
We exited SIA in December 2022, but we had already formed Atraverse that July. The three Co-Founders (Dr. Steven Mickelsen, Eric Sauter, and myself) each invested $25k and became equal partners and board members. Today, we are the only three board members even though we are minority owners now after having raised over $40 million, which I believe is a tribute to the trust our investors have in us.
Our first outside round of financing closed January 31, 2023, which was within 60 days of the SIA exit. Several SIA shareholders rolled over a portion of their proceeds into Atraverse, leveraging QSBS tax advantages.
I think we have had a very different fundraising experience than most medical device startup companies because Atraverse had a rapid, multi-million Seed I raise within roughly six months of founding the company. This was especially unique because we had only just filed our first patent in the prior month and only had rudimentary prototypes and preliminary data! In our Seed II round, we raised 50% more at a higher pre-money valuation and secured follow-ons from NYA and other new and existing angel investment groups; the Seed II round closed in April 2024. More recently in June 2025, we oversubscribed a $29 million convertible note financing including investment from new and existing investors. We also have world-renown cardiac electrophysiologists who invested across multiple rounds, which shows that our end-users and physician experts who truly understand the industry believe in our product and opportunity.
Today, Atraverse is very well capitalized with over $40 million of total capital raised from approximately 100 unique investors. We have grown to nearly 25 employees, and just posted our first month over $1M annual recurring revenue (ARR) in April 2025, with an exciting growth trajectory all the while maintaining our gross profit margin goal.
What have you enjoyed most about working with New York Angels?
Honestly, Mauri Rosenthal. Mauri is amazing; he is thoughtful, respectful, and inquisitive. One thing that I love about NYA is how your organization designates a liaison for portfolio companies. Having one point person makes interactions focused and efficient. I have worked with dozens of angel groups over the past 20 years, and New York Angels really stands out with its impressive investment capability and robust syndicate investor network.
NYA has also shown great flexibility from accommodating smaller check sizes when we were oversubscribed to working with SPVs to consolidate the number of investors on the cap. table, which is atypical and has also required significant support from us to make happen. The logical, rational approach to investing is something I really value about NYA.
What advice would you give to other founders who are fundraising?
Entrepreneurs ought to build a rockstar board of advisors consisting of people who have both fundraising experience and connections as well as medical device startup operating experience. Too many focus only on scientific advisors, but it is equally important to build business advisory boards at the same time.
Leverage your networks. If you are a startup, you are so small, and especially if this is your first company, you may not know many people. Early-stage startups can significantly benefit from networking in everything from introductions to potential investors, customers, partners, mentors, and more. I call it the archetypal networking game. The sooner you can tap into other people’s networks, the sooner you see the catalytic effects of knowing those in just 2-3 degrees of separation.
Know your market. Really understand the problem that you’re solving and whether people will pay for your solution.
Be relentlessly perseverant. Fundraising is a numbers game. First-time founders should expect to pitch to a much larger sample size of investors, especially if they don’t have a value-added board or network, in which case it’s even more important to remain vigilant.
Finally, fundraising is a team sport. Everyone can chip in and help, and the management team as a whole is often needed to bring investors across the finish line - as a team! I might have developed a reputation for oversubscribing rounds, but I have never seen a company fail from having too much cash. Raising money can be one of the hardest challenges in an early-stage medical device startup company, and I often find myself encouraging founders and boards to take a little extra cash, when available, because it allows the company to add significant value, extend cash runway, and delay the timing for the next round of financing. To note, typically the marginal dilution is fairly modest as well, plus founders share the dilution pro rata!
What advice would you give other early-stage investors?
Having a structure and a clear process for managing deal flow is important for founders. New York Angels does this well. I have heard some say NYA’s process can be a bit intensive, but I actually think NYA has found their way to the ’Goldilocks zone,’ which I would characterize as rigorous but not excessive. I find a lot of angel groups are superficial in their diligence or have no defined process whatsoever. NYA Members conduct real diligence and offer entrepreneurs a chance to have meaningful discussions.
I would encourage NYA investors and other angel groups to maintain the liaison model that I mentioned earlier as this helps entrepreneurs to focus their efforts. I also hope angels will be more open to SPVs and help find ways to make them more cost-efficient over time.
What has driven Atraverse’s success so far?
Atraverse has a very talented team. We have an exceptional set of co-founders: Dr. Mickelsen is a brilliant physician-inventor, and Eric Sauter is an equally brilliant engineer-inventor. We also have a talented quasi co-founder and co-inventor in Mr. Jay Kelly, who is an engineer by training but who serves as Chief Marketing Officer. The three of them are a force to be reckoned with between their prior med tech experience. We also have a world-class leadership team across all key disciplines who have collectively attracted additional talented personnel, and this is truly the secret to success in a startup: great people!
What motivates you personally and professionally?
I am a builder. I like to build things, so it is rewarding to build a company both in terms of shepherding innovative medical technology to market, but also in terms of recruiting exceptional people and retaining them with a stellar culture. Hiring the right people is a critical component to building a company, and I am extremely proud that Atraverse has 100% employee retention with no resignations nor terminations inception to date.
On the personal side, my 17-year-old son motivates me. He’s 6’4", 205 pounds, and absolutely shredded. Next year, I'll be 40 and an empty nester. He has motivated me to be healthier. I won’t be as lean as my protégé, but he certainly has inspired me to take my own health more seriously.
