TMDX Earnings Report

Earnings are out. Solid results. Not quite as great as I was hoping for, but 156% YoY revenue growth is pretty good. I will send notes from the conference call later tonight.

  • Net revenue of $52.5 million in the second quarter of 2023, a 156% increase compared to the second quarter of 2022.
  • Transplant centers’ use of the National OCS Program (NOP) drove approximately 93% of total U.S. OCS cases.
  • Signed definitive agreement to acquire Summit Aviation.
  • Acquired assets and IP related to the Ex-Vivo Organ Support System (“EVOSS”) and LifeCradle Heart Preservation Transport System technologies from Bridge to Life.
  • Completed convertible senior notes offering for approximately $393 million in net proceeds.
  • Results of OCS DCD Heart Trial published in New England Journal of Medicine.
  • Received CE mark for OCS Liver combined with bile salt as a Class III medical technology according to MDR, enabling commercial sales of OCS Liver in Europe.
  • Appointed Anil Ranganath as Senior Vice President, General Counsel and Corporate Secretary.

Looks like the algos hate the result. It’s down considerably. I bought another 1/5 share to bring it up 9.5% of the port


Yeah, humbling.

I sold about 1/6 of my shares after hours. There were a couple things in the call that I think spooked investors. Stock was up slightly on the initial news release, but it tanked during the call. Lots of uncertainty right now related to transportation.

Don’t have time to type my notes from the call right now, but will try later tonight.

I still believe in the company long term, but I think the next 3 to 9 months could be tough for the stock. I think the shorts are in control for the time being until we get some clarity on the aviation total costs and impact on profitability.


Just one more follow up.

Mgmt seemed defensive against questions asked. I’m not so sure it was anything other than being conservative and not being used to dealing with high growth expectations?

I didn’t like the response implying many aircraft would be required to support the mission (beyond the announced 2).

Also, a follow up question about aviation program impacts to margin, break even profits and timing led to a response that implied those considerations were secondary to building the network, organ transplant attainment against opportunity and quality of service.

On the face of it, it implies that mgmt either didn’t do the homework, didn’t care to share details that might not be favorable, or prioritized service quality and coverage over other factors.

I really appreciated the comments about losing opportunities. This team continues to be laser focused on capturing the market (and not losing transplant opportunities). This is the right long term vision for the team to have.

(and I would want this culture overseeing my donation or receipt of an organ!).

As an investor, they guided down. The response for the guide was:

  1. Holiday impacts (seasonal cyclical and expected)
  2. Conservatism
  3. Continued concern about losing opportunities as they build their network

While I don’t like #3, I am happy to see their will not let go of these lost opportunities as an area of focus.

AK70, it looks like I bought your shares! :smiley:


TMDX CEO is definitely a world-class sand baggers. They could easily raise 20M each for Q3 and Q4 to bring 2023 FY revenue to 230m. TMDX has been giving this extremely conservative guidance for many quarters already.

For anyone who is worrying about their growth, here is what the CEO said in Q2 CC:
“I don’t think investors should be concerned about where we are, we have a bigger growth wave ahead of us.”

“So I don’t want this to be misinterpreted in any way other than we are growing with a neck breaking speed and we need to take that time to acclimatize and integrate on our way to the top of the summit, and we’re not anywhere close yet.”

"So as far as the other capacity constrain, it’s really, we are not satisfied by the growth we are achieving now. - Look, they were not happy with 156% growth!!

The management explained well on why they have to own the logistics network by themselves:
"We missed cases in the quarter mainly lung , not because of supply chain issues, but because of logistical issues. We could not find planes to get us to where we need to be to achieve our missions. We’ve done the same – we lost few missions as well for heart and liver as well in Q3 because of lack of logistical support and capacity in the system . "

“And we need to beef up our surgical capacity, but most importantly, we need to get the TransMedics Aviation and TransMedics logistics, the broad logistics network up and running to be able to not to lose any case going forward.”

Owning TMDX as 2nd largest position


I view the guide as more flat. $94M on the books through Q2 with $96M needed to hit the top end $190M. That conservatism along with summer and holiday seasonality were the exact same reasons given for last year’s flattish second half guide. At the time, TMDX had posted $36M through Q2 with a $75M top end before outperforming in Q3 and Q4 to end at $93.5M.

I am also balancing those quotes with the ones @ZoroSGInvesting noted above. In the last five quarters management has raised the FY guide $10M, $10M, $10M, $25M, and now $20M. While tacking on an aviation network is quite a challenge, I have no reason to think TMDX won’t continue to meet and beat expectations going forward.

I didn’t go crazy but did add back a block of shares I trimmed at $80 on the way up in June. I’m personally OK for now keeping TMDX in the same 9-10% range it’s been the last few months.


The future growth path is quite clear, and in addition to transportation, they continue to expand product applications and the next generation OCS.

Currently, I have 6%, which will increase to 8-10%.


I have additional thoughts from the call, but I want to wait until I hear the Canacord presentation on Wednesday before commenting more. I reduced exposure because I was overweight and I want to see what they say in the upcoming presentation before deciding if I will add shares back. I love this company (as you all know) and I trust the CEO, but there are some things that are not adding up for me.

This is a forever stock for me at this point, so I will always own some shares, but I’m not sure if I want to have as much invested in them until I get clarity on some things.

FWIW I also reduced stock exposure pretty much across the board. I had gotten a little FOMO in the last few months, and I did pretty well with it in most cases, but I decided to go back to a higher % in cash for now. That’s just me - I often get panicky and can’t sleep due to nervousness about stocks and that’s my trigger that let’s me know I need to back off. I know that’s not the mantra of this board, and I’m not trying to influence anyone - just being transparent. I still have large (for me) positions in TMDX, TTD, NET, TREX and SOFI. Smaller positions in several others.


Sorry for not having time to comment more. I’m currently traveling for work and have not been able to write out all my thoughts. I will make time later this week after I listen to the Canacord presentation. I’m really hoping the CEO will be asked some more detailed questions about staffing for NOP, expected total costs for aviation (I don’t think we have any idea right now how much cash they have left and if they will need to do another raise), and I don’t understand how their revenue for lungs can be as low as it is.

FWIW - I trimmed more today.


Now after Summit Aviation acquisition, everyone was saying TMDX’s future gross margin would be lower. Is that really so?

According to TMDX 10-K, the transportation cost is part of “Cost of service revenue” and "Cost of service revenue primarily consists of labor and overhead and transportation costs that directly support organ retrieval and OCS organ management services. We expect that cost of revenue will increase or decrease in absolute dollars primarily as, and to the extent that, our revenue increases or decreases. "

IMO, if TMDX owns the aviation business and fleet, compare to paying 3rd party for transportation, I would say the in-house transportation cost would be lower after the acquisition is completed. And we might expect the gross margin of service revenue to be higher and therefore the total gross margin will be higher as well. Here is TMDX 10-K about GM:
We expect that the cost of net product revenue as a percentage of net product revenue will moderately decrease and gross margin and gross profit will moderately increase over the long term as our sales and production volumes increase and our cost per unit of our OCS disposable sets decreases due to economies of scale, our product enhancements and improved manufacturing efficiency. We intend to use our design, engineering and manufacturing capabilities to further advance and improve the efficiency of our manufacturing processes, which we believe will reduce costs and increase our gross margin. We also expect to see modest improvements in the future in our gross margin on services as we provide more services and the efficiency in provisioning of these services improves due to scale and experience. While we expect our gross margins to increase over the long term, they will likely fluctuate from quarter to quarter.

So there are two sides of the coin for this aviation initiative:

  1. The good - higher gross margin and higher revenue growth rate (they don’t have to lose the missions due to no planes)
  2. The not so good - the short term CAPEX in 1-2 years would be higher but that investment in inevitable for TMDX to maintain hypergrowth (similar to NET investing ton of CAPEX in the early days to build CDN networks).

Good thing is that with the economic scale, they are quite close to GAAP breakeven in Q2 and I believe they might be GAAP profitable starting Q3 and probably generating positive FCF from 2024 onwards.

With higher GM, why TMDX needs to be traded at lower multiples? Another buying opportunity today.



My understanding is the flight costs would raise service margins but slightly pressure overall margins. Here’s a CFO quote from last Q:

“Yes, Bill, from a P&L perspective, so today, the revenue for flights is not in our P&L. So we would think of that as an adder from a revenue perspective for each transplant, whether it’s $20,000 or $30,000 depends on the length of the flight. So that will be one change. So more of our revenue would be in the service bucket, although we think the service revenue, the service margin will be improved. The overall company gross margin percent may come down a bit. But from a dollar perspective, it should be an accretive to our income. And once we’re in positive EPS, it would be favorable to EPS.”

Ultimately, TMDX has now become an organ transplant and charter flight company. That certainly makes it more complicated. However, even at its peak management anticipates needing 10-15 planes. At the $10M-$12M per plane cost floated by an analyst, that would mean $180M max outlay even if TMDX needed to buy all 15 new (which doesn’t seem to be the case anyway).

We have no reason to think this management team hadn’t crunched the numbers repeatedly before announcing these plans and issuing notes to raise the funds at surprisingly favorable terms. With $580M on the books and very little cash burn, it seems there is plenty of money to back this initiative. Of course, the only thing management needs to do now is make it work.



I don’t have the transcript and I’m away from home and don’t have my notes from the call, but in the Q&A I’m pretty sure the CFO said there would be a need for more planes in the future.

I agree that they probably have enough money for now, but I would like someone to ask the CEO that question. How much money have they spent for the IP purchase, the acquisition, and the plane purchases?

The cash question is important, but it’s not my major concern. My major concern is around lung revenue - or lack thereof. And very little growth in heart revenue - in relation to the increased number of total transplants for both heart and lung. The numbers do not add up and that is what has me most concerned. I’ll try to explain better after the Canacord presentation. Maybe I’m worried about nothing. Maybe I’m misinterpreting the total transplant data and drawing wrong conclusions.

I thought TMF had copies of transcripts, but I can’t find any. If anyone can tell me where to get a copy I would appreciate it. Seeking Alpha now has them behind a paywall. I googled, but was not successful.


Yes @AnalogKid70 you are correct. They will need more planes. Here’s the CEO quote I used for the 10-15.

“This center will efficiently deploy the TransMedics aviation fleet from approximately 8 dedicated aviation hubs, capable of covering 100% of the Continental U.S. We will use a data-driven approach to continue to refine the national TransMedics transplant logistical network to maximize coverage, and efficiency of the operations. We have also begun the process of acquiring several additional aircraft to expand the TransMedics fleet, to reach our target goal of initially having 10 to 15 operational airplanes by the first half of 2024.”

I used this exchange for the $10-$12M per plane:


“Perfect. That’s very helpful. And then one last one, just in regards to the potential CapEx for planes. I don’t know if you mentioned this, but should we be thinking of outright purchases or leases? And then if it’s a purchase is a CapEx $10 million to $12 million range, is that what we should be thinking per plane? Thanks.”


“Yes, Ryan. I think in the near term, it is CapEx. It is purchases and the range is pretty close to what you just described.”

The CFO also stated they purchased two aircraft in early Q3, so we’ll get our first CapEx comments next Q. My guess given the post-earnings reaction is management will spend quite a bit of time on this topic at the Canacord presentation. The timeline in building out the fleet should also be reasonable enough we’ll get a chance to assess the CapEx progress as we go (hopefully).

I’m curious to hear your take on Canacord along with your heart and lung numbers if and when you get a chance to share. You know TMDX as well as anyone here, certainly better than I do. I’m just going with the consistently strong outperformance and a management team that expresses a clear roadmap for its success. Of course, that got me smoked on ENPH so take that for what it’s worth.

And as for transcripts, I have a free account at Their turnaround is pretty quick on most companies. Past transcripts eventually go behind a paywall, but I’ve never had a problem finding at least the most recent for any firm I want.


" initially having 10 to 15"

The word initially makes me think there will be more than 15 in the future.

Also, I thought there was another exchange later with a different analyst who specifically asked if there would be more planes in the future and the CFO indicated that yes there would be. I’m going off memory, so I could be wrong, but it kind of stood out to me when I heard it because it’s an open-ended expense.

Regarding lung numbers, I’m just going off the graphs I have shared in the past of transplant numbers for different organs. There was a significant jump in lung transplants in 2023 and I really expected that to translate into much higher lung revenue for TMDX. I’ll put together a summary with more details on this, but that’s the high-level question. Where are all those additional lungs coming from if not from TMDX? And why has lung revenue been stagnant for so long? Seems like the lung transplant community is not adopting it, but they are somehow still significantly increasing lung transplants.


You can find the CC transcript here (you might have to register, but it’s a free site):


@AnalogKid70 I hear you on lung.

But lung has had a long hiatus and was still up 100% qoq - so I was actually encouraged.

The real reason for a bit of a slowdown/tempering of the growth was a qoq slowdown in heart (which the ceo dismissed as a “blip”) and a decline qoq in international, which no-one seemed to have picked at. Would love to hear your thoughts on that?

I put the following together which shows the revenue breakdown per organ, plus international going back a few quarters with the latest quarter qoq and yoy growth per organ.

Revenue $m Q US Liver US Heart US Lung Non-US Total
2021 Q4 1.5 4 1.8 2.5 9.8
2022 Q1 7.9 3.7 2 2.3 15.9
2022 Q2 9.6 5.9 2.6 2.4 20.5
2022 Q3 12.4 8.2 1.3 2.4 24.3
2022 Q4 16.1 11 1.9 2.3 31.3
2023 Q1 23.1 13 1.4 4.1 41.6
2023 Q2 32.7 13.5 2.8 3.5 52.5
yoy 240.6% 128.8% 7.7% 45.8% 156.1%
qoq 41.6% 3.8% 100.0% -14.6% 26.2%

-wsm, long 8%


I took some notes on the Canaccord investor presentation today.

The CEO got into defense/lecture mode a couple times, but the info was solid. Nothing I heard either changes the difficulties of the challenge or my conviction about it. The Summit and Bridge to Life acquisitions totaled $45M with Summit being the lower cost, so it does appear TMDX has more than enough cash to build out the initial stages of its aviation plan with no real fear of another capital raise.

CEO’s opening:

  • Improved adoption rates in all organ categories

  • Highlighted business model change to end-to-end handling model (NOP). Called it “path to standard of care in this country.”

  • Talked about all stakeholders from insurers to hospitals to patients being aligned in improving systems. Also mentioned government bill currently being approved allowing TMDX and other voices to help revamp current national organ system.

  • Working toward launching products outside the US.

  • Views technology as a moat and believes owning own logistics network only increases that moat. Called it “game, set, match” for TMDX.

  • Mentioned kidneys as additional offering though no timeline given. (me: I don’t put much stock into this right now since we have plenty of other info to follow.)

Q: On disappointing heart revenues.

A: Grew number of clinics, repeat customers, overall heart transplants, and overall revenue. What couldn’t be mentioned on call was total number of heart calls much higher in Q2, but number of actual hearts donated fell short of expected as 53 DCD calls were serviced but didn’t turn into harvestable organs. (Me: DCD is “a donor who has suffered devastating and irreversible brain injury and may be near death but does not meet formal brain death criteria.” I feel a bit morbid writing that but want to remember there is a waiting recipient on the other end.)

If the patient doesn’t die during the time TMDX is called, it becomes a “dry run.” TMDX doesn’t want to avoid these DCD calls because the goal is to provide as many organs as possible to transplant candidates. This quarter’s smaller increase in heart revenue was simply a side effect of the DCD ebbs and flows with regard to dry runs. Management has “no fundamental concerns” with its heart growth or opportunity.

TMDX already knows it will double growth in 2023. Putting systems in place to make sure that growth continues in 2024 and 2025. Demand is there. Needs logistics and capacity to meet it.

Q: Does bottleneck include any shortfall in staff or any pushback from aviation providers knowing you will buy network?

A: No staffing issues or pushback. Strictly flight availability. Lost 12 lungs, 10-15 hearts, and 10-15 livers due to lack of flights. Said that represents $100K in revenue per case. (Me: So $3.2M to $4.2M in inaccessible revenue this Q. I guess the question becomes whether TMDX has tapped out the system until it gets its planes on line.)

Q: $70M in extra spend listed in 10K. Parse out at all? What are metrics for Summit? How many more planes?

$45M total for the Summit and Bridge To Life acquisitions. Summit was lower cost of the two. More details in Q3 with complete Summit metrics by Q4. (Analyst made it very clear Summit is mucking things up and pushed for modeling call if available sooner.)

Q: Any national partnering opportunities rather than buying planes?

No. No such thing as a national transplant courier. All regional mom-and-pops booked through brokers. The CEO said some brokers suggested acquiring them, but brokering isn’t the issue. Planes are. Compared it to mini-Amazon situation. Moving organs from San Francisco to Boston wasn’t possible before. Now it is. Estimate 25-30% gross margins on each flight with the benefit of increased volume tapping into higher-margin products especially 90% margin disposables.

Q: Will Summit be loss leader? Breakeven? How many more planes?

Plan to have 15 planes total by mid-2024. Now have four. Two from Summit and two more purchased in early Q3. Expects aviation to be accretive as a standalone but main impetus is to grow cases and increase other areas of business. (Me: This is the big unknown. We’re probably looking at $20-$25M for planes in Q3 with another $110-$130M more over the length of the buildout. We know they have the cash, but we have little info yet on outlays or margins. The four dedicated planes should help regain some of those missed organs starting in Q3. The risk is growth lags in the second half because TMDX has maxed out the rest of the transportation network. I guess we’ll see how the market reacts to this new info.)


I will type up some additional thoughts, but stocknovice captured many of the highlights.

One quick note to circle back to a topic discussed last night - The CFO clarified the question on number of planes. Summit has 2 that they lease and TMDX just bought 2 more. So they only have access to 4 of their own planes as of today. They plan to buy 11 more by mid-2024. Each one is ~ $12M, so I agree that they should be ok on cash for now.


OK, here are my thoughts on this. I had to put this together fairly quickly, but I did the best I could in the time available.

2023 Q2 – Thoughts from ER and Canacord Presentation

Disclaimer - I am not a medical professional, I don’t work in this industry, and it’s very possible I could have gotten something wrong in my conclusions. I’m sharing my observations to the best of my ability.

Let me start by reiterating that I still have some shares and I still believe in this company for the long-term. However, my personal opinion is that the share price could suffer in the short term due to a potential temporary reduction in revenue growth numbers. For that reason, I have reduced my % allocation.

My biggest concerns fall into two broad categories:

  1. Short-term - capacity issues due to
    a. aviation and
    b. internal perfusionist staffing
  2. Long term - lack of adoption of Lung OCS

Capacity issues:
In the last couple of quarters, the main capacity constraint was due to lack of TMDX’s internal production capacity to produce the OCS consumables. That no longer seems to be an issue and they have qualified their expansion on schedule. Great job by them to get this done quickly so that it is no longer an impediment to growth.

Aviation - The company has reported that they have missed out on potential organ donations because they did not have rental planes available for all of the potential organs offered to them in Q2. They had to turn down opportunities for over 30 organs in Q2 which would have contributed another $3M in revenue. TMDX plans to address this by purchasing an aviation company and creating their own nationwide network of planes and pilots to be dedicated to TMDX organ retrieval. This is great longer term, but it is going to take them 6-12 months to get this implemented and this could significantly limit their growth during that time. Long-term I am sure they can pull this off and I do agree that it is going to dramatically improve their moat as a business, but if it causes a short term drop in revenue growth, my concern is that the stock is going to be punished in the short term while the market waits for TMDX to implement this and prove that it can be successful. There is no way to know for sure how the market will react and what the stock price will do, but I am concerned that this could contribute to lower growth numbers and at least a temporary drop in the stock for a couple of quarters (or longer).
Another unknown is - can they get enough pilots. In the ER they stated that they are going to maintain the flight school in Bozeman, Montana (this was part of the aviation acquisition) - to funnel pilots into TMDX aviation. Will those pilots be willing to move to various parts of the US? If TMDX plans to have 15 total planes operational by the middle of next year, they need to probably hire at least 30 pilots - maybe double that amount if they want to have the planes available seven days per week 24 hours per day. I have no idea how easy or difficult it is to find that many pilots for this specific aircraft, but it’s one more risk.

Perfusionist staffing – In both the earnings report and the Canacord presentation, the CEO made comments regarding how much longer perfusionists are having to care for the organs compared with last year. He gave an example stating that in 2022 the average support time for a donated liver was 6-8 hours. In 2023 he said it was up to 24 hours. He stated that this “saps capacity” of their overall system because if somebody is on a mission for 24 hours straight they then need to be off for 24 hours before they can be redeployed. He did not go into specifics but he alluded to needing time to staff up in order to be able to handle the longer durations of caring for each individual organ. I’m sure this is a very solvable problem, but (again) it’s just one more risk and another thing that makes me concerned about the next few quarters of growth.

Lack of growth in Lung OCS
This is my bigger area of concern because this has been a lingering issue for years. The company consistently says they are working on it and it’s going to get better, but so far it’s not happening.
I have tracked revenue from lung OCS since 2Q2019. At that time, the lung product was fully approved by the FDA and commercially available. The revenue numbers for each quarter were as follows:
2.2, 2.1, 3, 2, 0.4*, 0.6*, 2.5, 2.4, 3.6, 3.3, 2.2, 2.3, 2.8, 1.5, 2.1, 1.6, 3.2
The number of lung transplants has barely moved in four years.

  • The 0.4 and 0.6 were the worst COVID quarters.

At the same time, the number of lung transplants made a significant jump in 2023 compared to the last few years. The chart below shows the total number of lung transplants for the last two years plus what has been completed so far in 2023. There have been 200 more lung transplants so far in 2023 than there were at the same time in either of the last two years. When I saw these numbers prior to the earnings report, I was expecting TMDX to have significantly improved results in lung revenue. I don’t know how else all of these lungs could be made available if not through the TMDX technology. I don’t have an explanation for this, but it made me start to really question if I am missing something else that is happening in the lung market that I am just not aware of.
In addition, the total number of lung transplants completed so far in 2023 is around 1500. Based on US lung revenue, TMDX has only provided about 40 of these – after 4 years of being commercial with Lung OCS.

Questions about lung OCS technology. I apologize that I don’t have the exact reference/wording for this, but I didn’t want to keep delaying writing something. I believe that in the earnings report there were a few comments made related to the new technology IP that TMDX just purchased last week and how it might be integrated with the existing OCS system. I believe the comments had to do with positive ventilation versus negative ventilation. I’m not expert in this, but I think it might be possible that there is an existing non-portable lung perfusion system which might use negative ventilation where as TMDX uses positive ventilation. I think there might be disagreement about which is better, and that might be part of why TMDX is struggling to get traction in the lung transplant community. It’s possible that TMDX might have purchased the lung IP because they need to in order to meet what the market is asking for. I think the CEO said the integration of this IP would not be available until at least the end of 2024. This is a lot of extrapolation and guesswork from me, but the comments just raised some additional caution flags for me when combined with the fact that lung OCS has struggled so much.
Final observation about lung results - Canacord did not ask at all about lung results and/or plans. Maybe I’m reading too much into this, but I was kind of surprised that they did not dig into this more. TMDX can be very successful if they never really break into the lung portion of the market, but in my opinion they don’t deserve nearly as high of a multiple if there is significant risk in the lung portion of the TAM.
So that’s it. I don’t have anything more concrete. You could call it an uneasy feeling. I did not feel comfortable having as high of an allocation in this company until they prove some things. This is now a 1% position for me.

Few Random Thoughts:

  • Their revenue growth for the last couple of years really has been tremendous. Aside from the issue with Lung OCS, I don’t think you could ask for much better execution from a company or leader. They are breaking down the barriers as they come, but the past results give confidence in the quality of the leadership.
  • Maybe my interpretation of the yearly transplant numbers on the UNOS website is wrong, and maybe there are not as many additional lung transplants as I thought there were. I am going based on what is published on the site, but I can not prove the reliability of the data I’m referencing for the total yearly transplant numbers.
  • Maybe there is another way that hospitals are obtaining more lung organs? If this is the case, then perhaps a competing process is taking share. Maybe Pargonix or EX Vivo or something else.
  • The CEO is a sandbagger, so maybe he is just sandbagging again for forward guidance. The problem with sandbaggers is that you never know when they are done sandbagging and the current estimate they are giving you is real.
  • The CEO said that they went on 53 “dry runs” during Q2 that did not result in obtaining an organ. He said that they will get better in the future at predicting which cases will not yield organs, but for now they are going on pretty much every case they are offered because they don’t want to turn anything down at this point.
  • The CEO said that each transplant is $100k in revenue. I assume he was rounding off, but that statement reconfirms the rough amount they get for each transplant they facilitate.
  • One interesting point he made that I had not heard before is that having an organ (specifically liver) on perfusion for a longer amount of time is actually better because the liver is functioning and producing bile and the physicians can measure the performance of the liver and have greater confidence in its viability the longer they see it function on the perfusion system. This is in contrast to cold storage which damages organs the longer they are stored prior to transplant.