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Biotech / Medical : World Heart Corp - WHRT and TSE/WHT -- Ignore unavailable to you. Want to Upgrade?

To: Mindshare who wrote (263)	5/20/1999 9:09:00 AM
From: the Chief	Read Replies (1) \| Respond to of 500

1) Granted, the first targeted market for most VAD's is bridge to transplant, hopefully followed by bridge-to-recovery (permanent implant). This is a logical sequence. I cannot imagine the Heart Saver would not be used as a bridge-to-transplant first. Anything else would be foolish and over-confident. It would be like trying to run a marathon before you could walk. Jarvik tried this with the Jarvik-7. The results were less than inspiring. Whoever dominates the bridge-to-transplant market will have a huge advantage in the permanent implant market. This assumes the device is capable of doing both. Clinical data is showing that the DeBakey VAD has a high probability of achieving this. whoever dominates the bridge-to-transplant market will have a huge advantage in the permanent implant market. I don't necessarily agree. Bridge to transplant may very well be dominated by one device and permanent implant by another. The recipients will probably determine that! In the case of a bridge to transplant, the less intrusive device would probably be the better unit, assuming both perform equally well. Whereas the longterm longevity and reliabilty of the device will dominate the decision for permanent implantation. They very well may be the same unit in the end, but only time will tell. 2) Cell damage and clotting are no more of an issue with the DeBakey VAD than a pulsatile pump. Cell damage levels for the DeBakey VAD are lower than some people even believe. Clotting is proving to be less of an issue with the DeBakey VAD than with pulsatile pumps. It's all in the design. Blood gets in and out of an axial pump so much faster than a pulsatile pump. Residence time seems to be an important factor. Actually the clotting issue is a concern, I have been told. The rotating impeller in the blood stream apparently creates the same problems that any rotating device causes in a liquid solution. Apparently the rotating impeller creates (for ease of explanation and my understanding) the equivalent of a "magnetic field" that attracts a film to the surface of the impeller and clotting is a concern. (Appreciate this is all hear-say, and is based on no fact, but also appreciate there is little information available on the deBakey unit at this point) The other issue that is of major concern is if the impeller stops! Apparently the path of the blood instead of "thru the body" is lessened because the "path of lesser resistance" is thru the stalled impeller. I am told that this is of such concern that the deBakey unit will be modified and fitted with valves (hear-say). 3) As for changing flowrate in response to physical exertion, we're not talking about taking a bedridden person and turning them into an Olympic athlete. Adding an additional 5 liters/minute will allow the patient to do all but the most strenuous tasks. When someone is able to go from complete lethargy to active walking, traveling, and normal social activities, it's a huge improvement in their quality of life. Actually, this is one of the disadvantages of the deBakey unit at the moment, the user has no control over the variance of impeller speed, nor does the bodies demand cause the impeller to change speed. You state it wouldn't take much to produce a variance of impeller speed to "create a pulse"! That is very true, however, you must now "electronically control the device" to mimic the pulsatile rate of the recipients heart. This is to ensure that the heart and deBakey unit stay in "sync" with each other....that the pulse created by the flushing heart, occurs at the sametime as the pulsating deBakey! 4)Organ damage from a continuous flow vs. pulse? Don't know much about that one. I do know if the patient has a pulse at all, the DeBakey VAD will follow it and in fact amplify the pulse. Will it do this as strongly as a pulsatile pump? Certainly not. Now we're talking about degrees of pulsatility. What's sufficient for long term organ health. (140/60,120/80, etc...) Keep in mind that the speed of an extremely lightweight impeller can be changed rapidly. You don't need much of speed change to make a pulse. It's easily done. Also, it's well known that after a VAD is implanted, the patient's own heart improves, sometimes dramatically. This would result in improving pulsatility over the long term. This is not conjecture, but actual proven fact. Add in all the features of a tiny, lightweight, low power, reliable pump and the competitive advantage gets pretty compelling. The volume of blood that the debakey unit can pump is also not an argument for allowing the patient to exert himself, the volume of blood must be variable based on the bodies needs at the time, the deBakey unit does not, in its present form, allow for this. All the things you describe, now raise the complexity of the deBakey unit to the level of the Heartsaver, which as originally touted was the saving grace of the deBakey....its simplicity! Couple this with the fact that the deBakey unit, as it exists right now, must have wires leaving the body to an electrical power supply and you really are talking about two totally different devices. To ensure the "variance of fan speed, to ensure its asynchronous function with the heart, to ensure its total body cavity integrity, to ensure it is "not" the path of lesser resistance....you have to build a non-pulsatile Heartsaver...which deBakeys unit is not. The things you describe can be added to the deBakey unit...but in doing so I then challenge its "description of being "tiny, compact etc. etc....it then becomes a "Heartsaver like" non-pulsatile unit. Disclaimer I have not one clue..of what I speak! I have literally no idea how difficult it would be to do the work described, the information I have compiled is thru reading the Ottawa Citizen as opposed to any reputable medical journal. The "shortfalls" I have outlined in the debakey unit are my perception and may be a long way from "reality"! And for God's sake don't invest in either unit based on my ramblings!! just trying to motivate a discussion! the Chief

To: Mindshare who wrote (263)	5/20/1999 10:09:00 AM
From: Dan Hamilton	Read Replies (2) \| Respond to of 500

Thanks for your comments. Of course I am influenced by my investment, but that doesn't mean I'm blinded by it. That's why I continue to research the rest of the players in the sector. Investments in these types of devices are of course speculative. I would liken them to a horse race. No doubt a number of these devices will eventually obtain approval. World Heart's initial production is slated for 2,000 devices maximum annually - a tiny fraction of the demand. I'm guessing that enough uncertainty will initially exist with respect to the overall desirability of a non-pulsatile device, that WHT should find a ready and willing market. Obviously, if they cross the finish line first (which I think they will) then it's even easier. Remember, right now the only alternative is death for Class IV patients. Frankly, I'd take whatever device my clinic could get their hands on. Right now, the most intriguing competitors, MicroMed and Apex, are not open to public investment. If they were, I might invest in all 3 as a hedge. Furthermore, who says you can't make money on the investment as you go along. I have sold and rebought 1/3 of my holdings in WHT a couple of times. I don't think World Heart needs to worry about raising capital at the moment. They have enough to see them through the clinical trials, including reasonable delays. The only issue might be if they encountered lengthier delays (say a year or more). Then of course, all bets are off. If they succeed, I don't think raising capital to expand should be an issue. Mindshare, you seem fairly knowledgeable about the DeBakey device. Are you a physician? You said cell damage levels are lower than some people believe. Do you draw this from the published literature, or have you spoken with the developers? You indicated before that you are not an investor in either MicroMed or World Heart, but you obviously have more than a passing interest in their progress. It would be helpful for me to know the context from which you write. I think it is great to have this type of discussion on the thread. The more information and opinions we can share, the better. It's not surprising there would be some differences of opinion here - I think it mirrors the situation in the medical community. It would be great if more physicians would post. Likely there are a few reading the thread (I always hated the term "lurking" :-))