Artivion, Inc. (AORT) Earnings Call Transcript & Summary

Greetings, and welcome to Artivion 4Q and Year-end 2021 Financial Conference Call. [Operator Instructions] As a reminder, this conference is being recorded. It's now my pleasure to introduce your host. I will now turn the call over to Brian Johnston from the Gilmartin Group. Thank you, and you may begin.

Thanks, operator. Good afternoon, and thank you for joining the call today. Joining me today from Artivion's management team are Pat Mackin, CEO; and Ashley Lee, CFO. Before we begin, I'd like to make the following statements to comply with the safe harbor requirements of the Private Securities Litigation Reform Act of 1995. Comments made on this call that look forward in time involve risks and uncertainties and are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. The forward-looking statements include statements made as to the company's or management's intentions, hopes, beliefs, expectations or predictions of the future. These forward-looking statements are subject to a number of risks, uncertainties, estimates and assumptions that may cause actual results to differ materially from these forward-looking statements. Additional information concerning certain risks and uncertainties that may impact these forward-looking statements is contained from time to time in the company's SEC filings and in the press release that was issued earlier today. Now I'll turn it over to Artivion's CEO, Pat Mackin.

Thanks, Brian, and good afternoon, and thanks for joining us on the call. This is our first call since rebranding as Artivion. This name was derived from the words aorta, innovation and vision and reflects our evolution to be a global leader, providing innovative treatments for aortic disease and our vision to continually innovate to maintain our position of leadership. It was time to change our name as we significantly evolved from the CryoLife I joined 7 years ago. During these past 7 years, as we continued to evolve, I would come across investors and customers who are not aware of the significant transformation that was taking place in our company. Investors and customers now have a fresh look at Artivion to see what we do and to learn more about our significant transformation. Artivion now encapsulates all that we've accomplished since we acquired On-X in 2016. Through a series of strategic acquisitions and divestitures and our new development initiatives, we've assembled a portfolio of products focused on aortic repair that we believe can compete with those of any company on the market today. We provide cardiac and vascular surgeons with innovative solutions to their most difficult challenges, and will continue to do so in the future as our product pipeline and new regulatory approvals will open access to our innovative therapies to many more patients around the globe. My goal since becoming CEO of CryoLife was to transform into Artivion. And our employees, by collaborating with each other, and our physicians have basically done just that. We now expect to organically grow our revenue double digits at the midpoint of our 2022 guidance. We believe our product pipeline and regulatory strategy sets us up well for continued success for years to come. Our rebrand followed on the heels of a record fourth quarter 2021 for Artivion as we posted strong quarterly revenue growth. Revenues for the fourth quarter were $79.4 million, that's up 16.9% compared to the fourth quarter of 2020 and up 18.8% on a pro forma constant currency basis. Revenues were up 13.5% on a pro forma constant currency basis compared to the fourth quarter of '19. Our growth in Q4 was driven by our stent grafts as well as our On-X product segments. More specifically, on a pro forma constant currency basis, comparing Q4 '21 to Q4 of '20, stents and stent grafts grew 33%, On-X grew 13.5%. Here, the growth rates for the products that are in the stent and stent graft segment: AMDS, up 20%; NEO, up 73%; E-nside, up 39%; NEXUS, up 233%. We also saw a return to growth in cardiac tissue as well as the relaunch of our TMR business. In all, we are pleased with our fourth quarter results despite continued and lingering headwinds from the Delta variant and Omicron variants that were associated with staffing issues and patient overflow issues in the hospitals. As I explained on our last call, our near-term plan is to accelerate revenue growth through 3 main initiatives. First, we plan to drive On-X growth while commercializing AMDS, NEXUS, E-nside and NEO, our new aortic stent and stent graft products. Second, we plan to further expand into Asia Pacific and Latin America by gaining regulatory approvals and expanding our commercial channels. Finally, to secure regulatory approvals for PerClot and PROACT Mitral in the U.S. and BioGlue in China. I will walk you through an update on each of these 3 initiatives. Starting with AMDS. This is the world's first arch remodeling hybrid device for use in the treatment of acute type A aortic dissections, we remain very optimistic on the product line given our experience to date. As noted earlier, during the fourth quarter, revenues increased 20% on a pro forma constant currency basis over the fourth quarter of 2020. Increases were driven by continued strength in Europe and the regulatory approvals in countries outside of EMEA and the U.S. Second, NEXUS posted quarterly revenues of 233% increase on a constant currency basis compared to the fourth quarter of 2020. Given the anticipated decline in COVID-19 infection rates associated with hospital staffing shortages and travel restrictions as well as improved physician adoption, we anticipate an uptick in NEXUS procedures in 2022. Third, E-nside, this is our newest device in our portfolio to treat thoracoabdominal aneurysms with endovascular stent grafts. Our revenues in this product line, which include E-nside and E-xtra DESIGN, grew 39% on a constant currency basis when compared to Q4 2020. Fourth, E-vita OPEN NEO. This is our newest product in the frozen elephant trunk category. This is used to treat dissections and aneurysms in the aortic arch. Revenues from this product line, which include E-vita OPEN PLUS and NEO, grew 73% on a constant currency basis compared to Q4 2020. Regarding Enya, we've decided to make modifications to the delivery system based on customer input and anticipate rereleasing this product in early 2023. We anticipate the demand for these products will continue to build as market adoption improves, COVID-19 infection decrease or become less virulent and hospital staffing shortages abate. Most of these products were fully launched during the COVID-19 pandemic or shortly before and, therefore, have not seen their full potential and environment not significantly hampered by the effects of the pandemic. In addition, while NEXUS and AMDS both launched shortly before the pandemic, they also benefited from our larger, more experienced sales force in Europe. Given the positive feedback we received in our newly offered products, I believe our growth in these product lines would have been even greater in the absence of the pandemic. Moving on to our next initiative, international expansion in Asia Pacific and Latin America through new regulatory approvals and commercial footprint expansion. I'm pleased to report that we are executing very well on this strategy. Our quarterly revenues on a pro forma constant currency basis increased in Asia Pacific and Latin America by 29% and 34%, respectively. Those are over the fourth quarter of 2020. We continue to expect these regions to be important contributors to our growth over the coming years as we continue to execute on this strategy. Regarding our third initiative, we continue to make progress on achieving 3 regulatory approvals in major markets. Our first is to attain U.S. a lower INR label for the On-X mitral valve. We've submitted our PMA supplement to the FDA, and it is currently under review. If our new label is approved, we believe lower anticoagulation levels will be a significant clinical benefit for patients. We are in active dialogue with the FDA. We continue to expect to receive PMA approval for the lower INR label of the On-X mitral valve, like our lower INR label for aortic valve sometime during 2022. If approved, we believe we will take significant market share in the U.S. with the On-X mitral valve just as we've done and are continuing to do with the On-X aortic valve. For PerClot, as you know, we filed a PMA with the FDA last quarter and we're working closely with the FDA. We still expect to receive approval from the FDA during the second half of 2022. If approved, for approximately 2 years thereafter, we will supply PerClot to Baxter and generate revenue. Lastly, as it relates to the regulatory approval for BioGlue in China, we remain actively engaged with NMPA and expect to have more clarity about a possible approval pathway within the next couple of months. In addition to our progress in each of these initiatives, we also continue to make strides in our midterm pipeline, with key products currently in the U.S. clinical trials and others are expected to start later this quarter. These 3 products are PROACT Xa, NEXUS and AMDS. We continue to make significant progress in enrollment in our PROACT Xa trial. This is our prospective randomized clinical trial to determine if patients with the On-X aortic valve can be maintained safely and effectively on Eliquis versus warfarin. We currently have enrolled 573 patients in this trial, and feedback from surgeons and patients participating has been excellent. We anticipate completing enrollment in the trial around the end of the second quarter of 2022. And assuming the trial meets its endpoints, we believe we can achieve FDA approval for this new indication by late '24 or early '25. If approved by the FDA, we believe the On-X aortic valve using Eliquis rather than Coumadin should become the market share leader in the aortic valve market in patients under the age of 70. As for AMDS, we recently received FDA approval to begin our pivotal clinical trial called PERSEVERE. The PERSEVERE trial is a nonrandomized clinical trial in up to 25 sites in the U.S. We expect to enroll approximately 100 participants who've experienced an acute type A dissection. The combined primary efficacy and safety endpoints of the trial are the reduction in: A, all-cause mortality; b, new disabilitating stroke; c, myocardial infarction; and d, new onset renal failure requiring dialysis; as well as the re-expansion of the true lumen of aorta. We anticipate enrolling the first patient this quarter and completing full enrollment by the end of this year. With a 1-year follow-up period, we anticipate we will receive FDA approval for AMDS in late '24. In addition to the progress we've made on the PROACT Xa trial as well as the AMDS trial, we also wanted to update investors about our partner, Endospan, and how they're making progress on their U.S. IDE trial for NEXUS called TRIOMPHE. As you recall, we've secured an option to potentially acquire Endospan. Due primarily to delays resulting from the pandemic, enrollment in the TRIOMPHE trial has been slower than anticipated. As a result, we do not believe an enrollment in the trial will be completed until sometime in 2023. We, therefore, do not anticipate approval for the NEXUS system until sometime in 2025, at the earliest, given the time required for follow-up, PMA submission and FDA review and approval. Given this delay as well as associated challenges related to market adoption during the pandemic, we've also fully impaired the value of the option to purchase Endospan and recorded as associated charge. Accordingly, we'd push the potential capital need out at least 1 year if we decided to proceed. With that said, we still remain bullish on the NEXUS technology, and Ashley will provide more color in his comments. If each of these 3 trials proceed as anticipated, we anticipate FDA approval for PROACT Xa, AMDS and NEXUS by late '24 or into '25, which would increase our addressable market opportunity by an estimated $1.5 billion. With that, I'll now turn the call over to Ashley.

Thanks, Pat, and good afternoon, everyone. Total revenues were $79.4 million for the fourth quarter, up 16.9% on a GAAP basis and up 18.8% on a pro forma constant currency basis, both compared to the fourth quarter of 2020. Revenues benefited from strength in aortic stent and stent grafts, On-X, cardiac tissues and the relaunch of TMR. On a year-over-year basis, in the fourth quarter of 2021, aortic stent and stent graft revenues increased to 31%, reflecting increased procedure volumes and revenues from our new product launches. On-X revenues increased 14% and BioGlue revenues increased 8%, reflecting improved procedure volumes relative to the fourth quarter of 2020. And tissue processing revenues increased 17%, benefiting from the release of tissue impacted by the TRIS hold in 2020. On a pro forma constant currency basis, compared to the fourth quarter of 2020, aortic stent and stent graft revenues increased 33%; On-X revenues increased 13%; BioGlue revenues increased 8%; and tissue processing revenues increased 17%. On a pro forma constant currency basis compared to the fourth quarter of 2019, On-X revenues increased 16%; aortic stent and stent graft revenues increased 37%; BioGlue increased 3%; and tissue processing revenues increased 4%. On a regional basis, fourth quarter 2020 revenues in EMEA increased 22%, Asia Pacific increased 28%. Latin America increased 31% and North America increased 12%, all compared to the fourth quarter of 2020. On a pro forma constant currency basis, revenues in Europe increased 27%, Asia Pacific increased 29%, Latin America increased 34% and North America increased 11%, all compared to the fourth quarter of 2020. Gross margins were 64.7% in the fourth quarter compared to 65.7% for the fourth quarter of 2020. The decrease was driven by higher-than-anticipated inventory obsolescence and inflationary impacts. G&A expenses in the fourth quarter were $51.3 million compared to $36.1 million in the fourth quarter of 2020. Excluding nonrecurring acquisition-related and business development charges of $10 million in 2021, which primarily consists of a noncash $4.5 million charge related to fair value adjustments for Ascyrus contingent consideration and a noncash $4.9 million charge related to the impairment of the Endospan purchase option and excluding $4.8 million in charges in 2020 primarily related to noncash fair value adjustments for Ascyrus, G&A expenses were $41.2 million and $31.3 million, respectively, in the fourth quarters of 2021 and 2020. With the impact of the pandemic and physician adoption on sales of NEXUS, both historically and in the future, we evaluated the purchase option relative to the purchase price and forecasted operating results and determined that it was appropriate to take an impairment charge. The remaining increase in SG&A primarily relates to personnel-related expenses, including salaries, commissions, stock compensation and travel as our spending returned closer to pre-COVID levels and additional expenses to support our expected future growth. R&D expenses were $9.5 million in the fourth quarter compared to $6.6 million for the fourth quarter of 2020, reflecting increased spending related to the PROACT Xa trial and investments to bring our aortic stent pipeline in the U.S. Fourth quarter interest expense of $3.9 million included approximately $2.5 million of expense related to our Term Loan B; $1.1 million related to our convertible debt; and approximately $300,000 in amortization of debt origination costs. Other expense in Q4 includes $2.9 million in realized and unrealized foreign currency translation losses. Income tax expense of $4 million in the fourth quarter reflects valuation allowances against deferred tax assets. On the bottom line, we reported GAAP net loss of approximately $20.1 million or $0.51 per diluted share in the fourth quarter. Non-GAAP net loss was $141,000 or $0.00 per share in the fourth quarter. GAAP and non-GAAP earnings includes the pretax loss of approximately $2.4 million or approximately $0.05 per share related to foreign currency translation losses. Adjusted operating income was $5.7 million for the fourth quarter of '21 compared to $11.1 million for the fourth quarter of 2020. Adjusted operating income reflects add-backs of amortization expense, business development and other nonrecurring charges to operating income. As of December 31, 2021, we had approximately $55 million in cash, $317 million in debt and the full $30 million available under our revolving credit facility. Adjusted EBITDA for the fourth quarter of 2021 was $10.8 million compared to $12.1 million for the fourth quarter of 2020. Net leverage, as defined by our credit facility, stood at 5.1x. On other balance sheet-related items, Pat mentioned our Endospan relationship. As he mentioned, given pandemic-related delays and commercial traction in Europe to date, we recorded an impairment in the value of the option related to this opportunity. While we remain positive on this product, the clinical timing delays push out any potential deal to acquire Endospan and any associated capital need by at least 1 year to 2025 or later. Please refer to our press release for additional information about our non-GAAP results, including a reconciliation of these results to our GAAP results. And now for our initial 2022 outlook. We expect constant currency growth of between 9% and 11% for the full year of 2022 compared to 2021. Using a euro-USD exchange rate of 1.13, revenues are expected to be $319 million to $325 million. The average euro-USD exchange rate in 2021 was 1.18, resulting in a $6 million revenue headwind for 2022. Our guidance assumes an impact from COVID during the first quarter of this year and a return to a more normal operating environment for the balance of the year, meaning limited deferred surgeries and staff shortages and more in-person selling. Although we do not anticipate a significant improvement in operating margin and adjusted EBITDA in 2022, we believe that we can comfortably continue to invest in our commercial channels in Asia and Latin America, our R&D pipeline and service our debt without having to raise additional capital. I will turn the call back to Pat for his closing comments.

Thanks, Ashley. So before we move to take your questions, I'll leave you with a few final thoughts. Our business momentum is strong, and we believe we have the strategy, the products and the team in place to continue that trend. We just posted strong year-over-year revenue growth despite COVID-related headwinds. We expect this momentum to continue into 2022, particularly into the second quarter and beyond. As I explained earlier, we have 3 short-term initiatives that will drive growth from now through the end of '24. First, we should see continued growth in On-X and our new aortic stents and stent grafts, AMDS, NEXUS, E-nside and NEO. Second, we anticipate further upside from our investments in our channels and new regulatory approvals in Asia and Latin America. Third, in 2022, we expect to receive PMA approval for PerClot and On-X PROACT Mitral in the U.S. And finally, we have a robust midterm pipeline with 3 U.S. PMAs that are currently enrolling, i.e., PROACT Xa or NEXUS TRIOMPHE or about to start enrolling AMDS PERSEVERE. Based on our enrollment projections for these 3 trials, we anticipate 3 PMA approvals in late '24 or into '25 and will expand our total addressable market by $1.5 billion. I would encourage all of you to join us in New York City for our Investor Analyst Day on March 23. It will be an excellent opportunity for you to learn more about our strategy, our products, our R&D pipeline and our leadership team. If any questions you'd like to attend in-person, please reach out to our Investor Relations team at [email protected]. Operator, would you please open the line for questions?

[Operator Instructions] Our first question is from Cecilia Furlong with Morgan Stanley.

This is Calvin on for Cecilia. Just 2 kind of buckets of questions. First off, I want to ask about the AMDS trial progress. So wondering if you could speak a little bit more to your confidence in enrolling this within sort of a 9-month period as you spoke to in your prepared remarks? How -- and how you think about potential COVID-related pressure on your enrollment that you've seen kind of in your other trials? And also just initial thoughts on driving awareness around AMDS? And then I had a follow-up.

Yes. So I think maybe one good surrogate is the PROACT Xa trial. I mean we started enrollment in that trial in May of 2022, about 6 weeks after COVID hit the U.S. And we've enrolled almost 570 patients during the pandemic. So we're on track to enroll 1,000-patient trial in 2 years under a pandemic. I think the second thing about AMDS, we've got the IDE approved. We should enroll our first patient this quarter. We have 25 centers. The trial is about 100 patients. Those 25 centers represent the largest aortic centers in the country. I've personally visited all of them. I know how many cases they do a year. And this is a life-saving procedure. These patients are typically Medevac in at night. So COVID's the least of people's worries when it comes to acute type A dissections. So there's always kind of the contracting and getting through IRBs and these kind of things. It takes time, but we feel that given the importance of this technology, the lifesaving nature of this procedure, that with the centers we're in and the volume that they do, that we should enroll this trial pretty quickly.

Got it. That's very helpful. The second one is just on margins. I have 2 checks. One is on gross margin. I wanted to dig a little bit into the sequential compression. So just curious what's reflected in 4Q associated with kind of your tissue coming back versus inflationary pressures that you spoke to? And how you think about that jumping off into '22? And then also on the R&D cadence in '22 between PROACT Xa, ramping AMDS and just other drivers, what would drive that R&D cadence in '22?

Yes. So gross margins, as you know, are a combination of many moving parts, right? So clearly, the inflationary pressures from whether it's increased labor costs or increased materials are baked in there. The second thing we've seen in '21 is increased obsolescence, primarily around we were staffed up and had product in the field to support the normal growth rates. And we just had more exposure to obsolescence given the kind of the volume reductions. And then third, as you mentioned, there's mix, whether it's international or our product line. And we did see a higher return to growth of our cardiac tissue, which is a lower gross margin than our -- kind of our high-end devices. So it was kind of a mix of all those things. And clearly, the inflationary pressures was one that was unforecasted at the beginning of the year. And then maybe you can comment on the R&D actually.

Yes. So we ended up fourth quarter at about $9.5 million in R&D. And clearly, PROACT Xa continues to ramp up. We're going to be starting AMDS, but we're also going to have some R&D efforts that are going to be rolling off this year. We invested a lot of money in getting to the point where we could submit PerClot to the FDA. So we are going to have some progress. And PROACT Mitral just recently wrapped up as well. So with all that being said, we think that R&D in 2022 is going to be in the high $30 millions to the low $40 millions, and a lot of it will just depend on the progress that we make with the programs.

The next question is from Jeffrey Cohen with Ladenburg Thalmann.

So firstly, could you talk a little bit about the aortic stent pipeline? I know you had some manufacturers and throughput issues out of JOTEC, and you were putting up a second source under development. What's the status there? And are you caught up? Have you caught up? What are the plans going forward?

We grew 33% in the fourth quarter.

So no issues on backlog whatsoever?

Yes. We brought in new selling suppliers, as we mentioned. We've built a new facility, which is not up and running, but we've had no issues on the supply side. And I said, we put up -- depending on which number you want to look at, versus '20, we grew the stents and stent grafts almost 30%. And versus '19, we grew them 22%, so...

Got it. Fantastic. Okay. And then could you comment a little bit on your channels and the size of the commercial force for Asia and Latin America? And how you're tackling that as far as direct versus distribution arrangements?

Yes. So we've talked kind of consistently over the last probably 18 months about we see this as one of our growth drivers. And we saw a nice performance in both of those markets this quarter. I commented on the growth rates in Asia Pacific and Latin America. We're seeing 34% growth in Latin America and 29% growth in Asia. Those channels, we're expecting to build Asia up more. It's obviously a bigger geography. So I think there's probably another 15 to 20 people we'll be adding there over the next 3 years. Probably half of that in Latin America. And then we basically are fully staffed up and don't need to add any more. So it's an investment that's actually returning, right now, really nice growth rates. And we're also feeding the regions as they grow. So when COVID hit, we kind of slowed it down. And then when things started loosening it up, we started adding people back on. But we expect to have that investment probably flattening out itself in the next 24 months.

Okay. Perfect. And then lastly for us, Ashley, any comment on the $10 million integration severance and business development from Q4? Is that onetime in nature? Or should we expect any further impacts into the first half this year?

Yes. The fair value accounting for the Ascyrus contingent consideration is something that we will see every quarter going forward until the milestones are fully earned and paid and that's way out in the future. So going forward, our best estimate right now for Ascyrus is maybe $1.5 million per quarter. But again, that could change based on a variety of factors, progress that's made, discount rates, there are a lot of things. But that's our best guess. For Endospan, the option is fully written off. So you won't see any charges related to that. we do have an obligation to pay them another $5 million once they reach 50% enrollment in their clinical trial. We anticipate them hitting 50% at some point this year. And whenever they reach that milestone and we make that payment, there will be a $5 million charge approximately in other expense.

The next question is from Mike Matson with Needham & Company.

I guess I just want to ask about the revenue guidance. So you just grew 19% on a pro forma constant currency basis. You're guiding to around 10%. I mean I understand there's some COVID impact expected, particularly in the early part of the year. But why the slowdown, I guess? And I guess, as a follow-up to that, just was there any kind of one-offs in the fourth quarter that helped your growth that aren't really sustainable, I guess, but maybe that's probably why you're guiding forward?

Yes. I think the biggest issue, Mike, and again, this is one that's probably not common for a lot of companies of our size that have single products and are mostly in the U.S. I mean almost 40% of our business is in Europe, and the euro has dropped 7 points in the last year. That's a $6 million headwind. So if people are kind of taking our Q4 number and trying to straight line it out to next year, it's the wrong math equation. I mean the euro a year ago was 1.22 this quarter, and now it's 1.13. So we got a serious headwind when it comes to the euro in Europe, and we have a big chunk of business there. So it's got nothing to do with our -- we're backing off on what we think is going to happen. It's more -- we got a lot more to do with the headwind on currency.

Yes. And the other thing, Mike, too, is that 18% growth, that was against the fourth quarter of '20. We were up 13.5% against the fourth quarter of 2019. So we're guiding to between 9% and 11% versus, again, if the comparison is 2019, it was 13.5%.

Yes, I don't think -- yes, I think the big thing people aren't catching is the currency, right? Because if you revalue 2021 revenues at the new currency, our $298.8 million turns into like $293 million. It's the 7% drop and it's all currency. So we're saying we're going to grow 9% to 11%. You just got to -- I'm not going to get set up with -- I can't control currency.

Yes. No, I understand that. I mean it's consequent to guidance. So that's fine. Okay. All right. And then let's see. So just want to ask about the first quarter specifically. It sounds like you're expecting some COVID impact there. I didn't really hear any specific revenue ranges or anything. It looks like consensus is just under $79 million, which would sort of imply 11% growth versus the first quarter of '21, if my math is right. So that probably too high based on what you're saying because of your full year guidance. I mean that's at the high end of the range for the full year.

Yes. So that $79 million has no impact of the 6% drop in currency. So I think people need to readjust their numbers based on the 2022 currency. And we're giving -- we've given full year guidance, 9% to 11%. And clearly, COVID is an issue in the first quarter. I mean January was slow. In our checks with hospitals, the -- a lot of these hospitals had as many patients in January as they did at any point in the pandemic. They were reducing elective procedures. The bigger issue is, frankly, hospital staffing. I think the good news is we're seeing cases drop, hospitals emptying out and staffing coming back. So we don't think it's going to persist, but we definitely think Q1 is going to be lighter than the rest of the year.

Yes, Mike, this is Ashley. So I mean, to Pat's point, talking about currency, last year, we posted $71 million in revenue. And if you take into account the change in FX rates, that $71 million translates to $69 million. So that's really the base that you should be looking at. And if you just take the midpoint of our guidance that we guided to, which is 9% to 11%, 10% on top of that is 76%. And as Pat indicated, the COVID's really had an impact at least to date this quarter.

Yes. Okay. I understand. All right. And then just as far as On-X Mitral goes, so when you hopefully get that approval for the lower INR, how quickly do you think the uptake will be on that? I mean you've talked about it being, I think, a $40 million, if I remember right, opportunity.

Yes.

So how quickly can you get to $40 million, I guess, there?

Yes. I think you've seen -- I mean, we have a great case study, right, because we've already done this. We did it on the aortic side, where we got the exact same -- it's the sister product, right? We had a lower INR for the aortic. It has to -- the paper has to get out. It has to get socialized and educate -- you have to educate your physicians. The great news about PROACT Mitral is we -- again, we've already done it with aortic, number one. Number two, the valves are already on the shelves. We have mitral valves in probably 500 accounts in this country. So all that's going to happen. The label is going to change, and our reps are going to market the paper. So as far as like making new product and getting it out and all that, what happens with a lot of our other products, that doesn't exist. We already have product on the shelf. So I think we're going to see a steady increase in the mitral like we did with On-X aortic over the next 3 or 4 years.

Our next question is from Suraj Kalia with Oppenheimer & Company.

Pat, Ashley. hope everyone is safe and healthy. So Pat, On-X Mitral, I'd love to get you guys' perspective what has the reception been on the data? And if I could piggyback on the previous questioner, On-X aortic, right? If my math is right, like within 5 years, you guys became pretty much the market leader in your day. Just kind of map us the trajectory of On-X Mitral, if you could, knowing that this is, let's say, a $40 million, $50 million opportunity in the U.S.

Yes. No, I think it's a good point and dovetailing off Mike Matson's question. I mean I'm looking at the On-X numbers. So compared to 2021 versus '20, we grew On-X 18%. '21 versus '19, if you think that's too easy, we grew 14%. So here we are 5 years after we acquired them and after they got the indication. And given the pandemic, we had a little bit of a slowdown in the pandemic. But we've basically grown On-X double digits every year for the last 5 years. So one of the things you see, and you know this well from -- as a new paper gets out, you've got to educate your physicians, you've got to look to get the guidelines changed. And I do think we have a kind of a tailwind because we just did it for the last 5 years with On-X aortic. So I think that the brand represents a different valve within a coagulation. So I think the steps here are getting the publication out, educating physicians and obviously, we've got to get the FDA approval, right? I mean we can't really do any of this stuff until we get the FDA approval. Once we get that, I mean, the products on the shelves, our reps know the surgeons and we'll present the data. The feedback we've had has been excellent. We've got a lot of market research. I mean, again, it's a little bit like the aortic valve in that, why wouldn't you want a lower INR if you're a patient who's going to get a mitral valve? We've shown that we can protect the valve with less Coumadin in the aortic position and that was very well adopted. And now we're -- we've done it with the mitral valve. So I think it's -- you don't get it all. You don't get all $40 million in 1 year. Nobody does that, right? It's a technology adoption and uptake. But I do think it's going to probably go faster than the aortic did.

Pat, PROACT Xa, 570 patients enrolled so far, if I heard you guys correctly.

That's right. That's correct.

Do we need to -- or do you anticipate a pickup in enrollment to maintain the Q2 timing for finishing up enrollment?

Yes. I mean, I think we continue to add centers. So we're -- we've got 60 centers signed up. We have 55 on board at this point. So we've got 5 more centers coming in. And we typically see a bolus of patients when a new center comes in. And we've seen nice enrollment. I do think -- I think it's not misstating it, when you see a massive surge in a hospital, like in January, I think it's fair to say that clinical trials probably get impacted. People are busy in doing other things. So I think it's helpful for us as things kind of calm down on the COVID front with the hospital that it should help. But we're -- I mean, we're very aggressive. We're having regular investigator meetings, but we've got the centers all up and running. It's now a matter just of putting the foot down and getting these patients in.

Fair enough. And Pat, last question from my side, and I'll hop back in queue. So Pat, you've been there 7 years, right? Take a step back, and obviously, you have transformed the company. And I'm curious, as you look at it at the cutting junction, how would you characterize, let's say, average rep productivity, average revs per account? What do you see as optimal levels? What does the gap analysis tell you? And how do we fill that gap?

Yes, thanks. Yes, so I think it depends on the region, right? So if you look at Europe, we've thrown a lot of new products with them, right? We acquired JOTEC and then we brought on Endospan with NEXUS and then we brought on AMDS. We've launched E-nside. We've launched NEO. So it's like we've got kind of a treasurer of products in Europe where they've got the whole pipeline. So I would say that, that group is extremely busy. The U.S. team, as a kind of comparison, they haven't really got any of the new stuff. But they've got PROACT Mitral coming and they're very well positioned for that. So we've got kind of 60 feet on the street in the U.S. They're well positioned for PROACT Mitral. They're well positioned for PROACT Xa when it comes. They're well positioned for AMDS. And I think that's one that people don't necessarily grasp. And a lot of these businesses that I've been, you've really got to add a lot more reps when you bring in new products. We don't need to add any more reps. I can add $400 million worth of new revenue into the U.S. and not add a single rep. So I think that's one of the real kind of secret sauces of Artivion, is once we finish our investment in Asia Pacific, and maybe some spotty things here and there in Europe as you maybe go direct in countries and we're mostly direct there now, we're going to kind of flatten out our investment in direct distribution. And all these new products that come through, we're going to see significant drop-through to the bottom line, accelerating growth and accelerating gross margin as well as just sheer drop-through because we don't have to add any more reps. So I think it's a unique thing about cardiac surgery in particular, where you can cover a lot of accounts without a lot of reps. Okay, operator, any more questions?

Mr. Mackin, there are no further questions at this time. I would like to turn the floor back over to management for closing comments.

Okay. Yes. Well, first of all, thanks for joining today, and we appreciate you spending some time with us. And we've tried to simplify the story to a pretty digestible plan, which is Phase I or the current growth initiative. Number one is our new products, right? We were showing significant growth. Our On-X platform grew this year 18% versus '20 or 14% versus '19. Our stents and stent grafts grew 28% versus 2020 or 22% versus '19. So any comparator, we're talking about nice growth that is driving the growth of Artivion. So that's our first pillar in our growth. The second is Asia Pacific, Latin America. We talked about the growth rates in those 2 regions. We continue to invest in those areas. The third is we've got 2 PMAs that should come through this year. PerClot, which will give us a $25 million payment from Baxter, and then revenue that we sell to them. And then PROACT Mitral, which we talked a lot about on the call. And then the fourth piece of the puzzle is 3 PMAs. We're enrolling PROACT Xa. We're 57% of the way done with that trial. We expect to enroll in the first half of this year. We expect to enroll our first patient in the second trial PERSEVERE, which is AMDS. And we're still pursuing FDA approval with the NEXUS device. So I think we've got a great story, and we're looking to deliver the numbers we talked about and look forward to updating you on the next call. So thanks for attending.

Thank you. This concludes today's conference. You may disconnect your lines at this time. Thank you for your participation.