IMAT.... What Motley Fool Has To Say...
.......................................
Technology or Economics?
[EDITOR'S NOTE: Today, Rogue looks at Imatron Corporation, makers of a new heart scan
technology that earned the company considerable market interest. After its stock price
jumped quickly, though, the shares came back to earth. What's the real value of Imatron's
technology? How seriously should we take criticisms of it from the medical establishment?]
Earlier this month, the American Heart Association issued an official report on Imatron
Corporation's much talked-about Ultrafast CT heart scan technology. The AHA statement
expressed considerable skepticism about the value of the technology and emphasized potential
objections to its widespread use.
The report was far more ambiguous than expected, since a recent spate of positive scientific studies
had suggested that Imatron's technology is remarkably valuable as an inexpensive, non-invasive
screening and diagnostic tool for coronary artery disease. Investors looking for a quick jump in
Imatron's stock price were sadly disappointed.
The AHA statement triggered several related discussions. Some individual investors in THE
MOTLEY FOOL's Imatron folder complained that a number of committee members had conflicts
of interest that biased them against the test. Meanwhile, Imatron's President and CEO Lewis Meyer
attempted to put a positive spin on the AHA's findings, going as far as accusing THE WALL
STREET JOURNAL of inaccurately reporting the committee's recommendations.
The most interesting complaints, though, have come from exasperated members of the research
community itself. A number of doctors involved in important recent studies employing the Ultrafast
CT scan, known generically as Electron Beam Computed Tomography (EBCT), were simply
dumbfounded by the AHA's statement.
In telephone interviews with ROGUE, these doctors argued that the recommendations are
unnecessarily conservative. According to these researchers, the principal objections to the scan's
broad adoption both as a primary screening test and as a management tool for middle-aged
Americans suffering from coronary artery disease have already been answered.
Indeed, some doctors advocating use of the scan believe that the AHA statement was derailed by
still obscure political considerations. While they each offered somewhat different explanations, the
politics in this case may be largely economic. The scan may threaten cardiologists, in part because its
use might dramatically improve efforts to prevent coronary artery disease, and thus decrease the
number of angioplasty and bypass procedures that are conducted.
In following this story, it's worth starting with Imatron's press release of September 4th which
commented on the lenghthy statement printed in the September 1st issue of CIRCULATION, the
AHA's journal. Imatron proclaimed that the new report represented a significant extension of the
AHA's previous position on Imatron's scan. This was in fact the case. As the company put it, the
AHA "now acknowledges the role of EBCT in the diagnosis and management of coronary artery
disease." According to "extremely pleased" Imatron CEO Meyer, the statement "clearly places our
Ultrafast CT Scanner in the mainstream for the diagnosis of coronary artery disease."
THE WALL STREET JOURNAL, however, offered a very different account. In a September 5th
article, JOURNAL reporter Amal Kumar Naj indicated that the AHA had concluded that the
EBCT scan "can detect the risk of coronary heart disease, but warned doctors against using the new
tool indiscriminately."
The article concluded with a quote from Dr. Lewis Wexler, a professor of radiology at Stanford
University Medical Center and chairman of the scientific committee that wrote the report. "We are
still looking for a way to predict which patients who don't have symptoms will develop a heart attack
or acute chest pain."
Alarmed by this negative account, Imatron itself issued another press release that day rebutting the
JOURNAL'S interpretation of the study.
"No where [sic] does the AHA 'warn' doctors against using EBCT indiscriminately," Meyer said.
The guidelines, indeed, were those used by the company itself. "We, too, have consistently
maintained that EBCT should not be indiscriminately used as a screening tool in people under age 40
who do not have symptoms of or known risk factors for heart disease. EBCT has been
demonstrated to be effective in screening individuals over age 40 with either known risk factors for
or symptoms of coronary artery disease.
"We are also perplexed by the concluding quote in the article since it is in direct contradiction to the
conclusions of the AHA's Statement, as well as a recent study highlighted in the June issue of
CIRCULATION, the journal of the AHA, which reported that Imatron's Ultrafast CT scanner is
'more powerful than the best non-invasive test in predicting heart attacks and other coronary disease
episodes, even in apparently healthy people.'"
At the heart of the controversy is the AHA statement itself. On the one hand, it does endorse the
scan for diagnosing and managing coronary artery disease. But it does so in the most backhanded
terms possible. Given Wexler's public statements to the JOURNAL, it's clear that Wexler was one
figure who influenced the report's strongly qualified endorsement of the EBCT scan. Such a
lukewarm recommendation was only possible if Wexler and the committee dismissed the evidence
offered by recent studies or explained it away as biased or simply insufficient.
Indeed, the June 1st paper in CIRCULATION directly contradicts Wexler's statement to the
JOURNAL. In that study, Dr. Yadon Arad, Dr. Alan Guerci, and other researchers at St. Francis
Hospital in Roslyn, New York showed that the EBCT scan offers the best way to predict which
people without symptoms will go on to develop heart attacks or other cardiac events.
EBCT measures coronary calcium, which is one component of the plaque build-up responsible for
atherosclerosis, or hardening of the arteries. The amount of coronary calcium is correlated with
narrowing of the arteries, particularly as the arteries become more dangerously clogged with plaque.
Arad's paper revealed just how useful the scan can be.
The St. Francis study looked at 1173 asymptomatic people, 71% of them male, with a mean age of
53. During 19 months of follow-up, 18 patients experienced a coronary event (such as death, a
heart attack, stroke, bypass surgery, or angioplasty). Forty-four patients developed angina.
The study showed that these previously healthy people who experienced cardiac events had calcium
scores more than *six times greater* than the subjects who did not experience events. Additionally,
people who went on to experience angina pain scored more than twice as high, on average, as those
who did not.
Perhaps most important, the study revealed that aside from age, no other coronary risk factor
(including high cholesterol, low HDL cholesterol, hypertension, smoking, diabetes, or a family
history of premature atherosclerotic disease) correlated with a subsequent cardiac event. In short,
Imatron's EBCT fit Wexler's bill perfectly.
Given the results of this large study, the AHA committee might have opted for a rather broad
recommendation encouraging all middle-aged Americans, say men over 45 and post-menopausal
women, to take an EBCT test every 3-5 years as part of a routine screening to detect and prevent
coronary heart disease. A more conservative stance would have been to recommend such screening
only for asymptomatic people of middle age who have more than one risk factor for the disease. The
committee recommended neither.
The panel laid out three possible practical applications of the test. It could be used to evaluate
patients with chest pain to determine if a stress test, angiogram, or further medical therapy was
required. It could be used to screen asymptomatic subjects. It could also be used to follow the
progression of atheroslerosis and to help determine whether nutritional or pharmacological
treatments were working. The AHA committee basically gave only the first and third of these
applications a (qualified) vote of confidence.
The statement deemed the current data insufficient to recommend the EBCT in place of a
conventional stress test for most patients with chest pain, "except in those with atypical chest pain,
for whom a negative study may be useful by itself." Some 30% of people presenting with chest pain
in emergency rooms each year do not have heart trouble, and the EBCT can quickly specify these
individuals, who can then be examined for other problems. This clear recommendation of the test, if
widely adopted, should save millions of dollars in unnecessary hospitalization costs as well.
Next, the statement said that the test could be "used as part of a cardiological examination" by a
physician knowledgeable about the test and the management of heart disease. But the panel argued
that reproducibility of calcium scores on the exam is "insufficient for serial assessment" of calcium
levels in individual patients.
What this means is that the committee suggested the test might be used in management of coronary
artery disease but instructed physicians not to use calcium scores as a surrogate marker to help
determine whether the disease was being controlled or not.
Finally, the AHA report came out against use of the test as a screening tool for asymptomatic
patients below the age of 40. "The importance of calcification in such individuals will have to await
event data that are currently being obtained." The panel also rejected use of the scan as a screening
test for people with conventional risk factors, because its role in these patients "is not yet clearly
defined."
There are a number of problems with these conclusions. First, the committee remained silent
concerning exactly the group of people examined in the St. Francis study. As Dr. Arad told me,
"What happened to people over 40 who don't have symptoms? They make no recommendations for
people over 40 for screening purposes."
According to Arad, the EBCT is "as good a screening test as we have in this world." In people age
45 and up, "it's a hell of a lot better than a stress test." He says that while the June CIRCULATION
paper is the only one published on the subject so far, there are three other abstracts that support his
group's conclusions. Those studies cover more than 3,500 people.
Indeed, Arad believes the committee's objections to the St. Francis data for selection bias and use
of ambiguous endpoints, such as surgery or angina, are unfounded. He believes that an objective
analysis of the data would lead to the "unavoidable conclusion that this test will tell you who has
heart disease and who is likely to have an event if you have a screening program."
"At what point do you say that you have enough data?" he asked. "From a scientific point of view, I
have no problem saying that I'd love to see a study of 40,000 people over 12 years. The question is,
should we wait 12 years before using the test? For years, we've been looking for this holy grail that
would allow us to identify the subjects who are most likely to benefit from [preventive] treatment...
And here it is."
A second problem with the statement is that the AHA committee essentially validated the use of the
test to help manage coronary heart disease while simultaneously saying the the test suffers from
significant reproducibility problems. But according to Dr. Paul Shields, a cardiologist in Spokane,
Washington, that's not true.
Shields has been involved in a number of recent studies, including investigations into the scan's
reproducibility. Shields said, "The test is not as variable as reported, if you're careful with [it]." He
said that the data he's collected argues that, with skilled technicians, there's no problem reproducing
results with very high accuracy. "I don't know why the committee concluded that our data is not
sufficient. In my experience, it's an extremely repeatable test. They just don't want to accept the
data."
What is most surprising, though, is that the AHA statement does not recommend use of the test to
screen asymptomatic, middle-aged people at risk for heart disease. As Arad pointed out, the EBCT
has been shown to be the "single best test we have" for this group. Indeed, in an abstract published
last year, committee members Dr. Bruce Brundage and Dr. Robert Detrano, both of Harbor UCLA
Medical Center, reached this same conclusion. "Coronary calcium does predict death and
myocardial infarcation in high-risk asymptomatic adults."
In a phone interview, Detrano rejected his group's own conclusion. He said that the study covered
only a small number of patients and that more recent data from the same patient sample offers a
more ambiguous picture. Indeed, despite having done a significant amount of all the work conducted
on EBCT, Detrano offers a far more conservative interpretation of his data than do others who have
studied his results.
Detrano was clearly a strong voice restraining the committee's recommendations. He said there's
simply insufficient data to back wider acceptance of the scan. Though advocates of the Ultrafast CT
(such as Brundage) call it "potentially a mammogram of the heart," Detrano pointed out that there's
far more data to support the use of mammograms.
Indeed, he believes that the AHA's recommendation is a timely liberalization of the association's
previous stance on EBCT. Only future studies will determine whether the test can be used as a
broader screening device. In talking with him, one gets the impression that the process of
accumulating those data could take years.
Other doctors I spoke with, however, suggest that Detrano may be interested in protecting his
research interests. As one doctor in the field said, "Research can only be done when an answer is
not known. So if they know the answer, their grant money runs out."
One physician who has worked with him described Detrano as an enigma. "We get these
preliminary papers, and you think, well that's a super paper. Then it's published and there's all this
negative comment at the end of the paper saying that is hasn't quite been proved yet. Then when you
talk to him, he says it's the best test he's ever seen."
This same researcher said, "My personal feeling about the [investigative] community is that I'm not
sure how honest they are. Maybe it's because of all the trouble they have with funding, but boy,
there seem to be a lot of games going on."
Some individual investors on the FOOL have suggested that the chief conflict over wide acceptance
of the EBCT scan is between radiologists such as Wexler and cardiologists such as Detrano. The
scan was originally used by radiologists. But as its utility in detecting coronary calcium has become
clear, this technology, like other imaging technologies that were once the main province of
radiologists, has increasingly fallen within the cardiologists' domain. Still, there are other issues
related to economic and institutional reputation at play here.
As one researcher I spoke with said, "Unless you're completely innocent, you would have to surmise
that this could be a tremendous economic risk [for cardiologists]. Here's a test that can identify
people at an early stage of heart disease and hopefully prevent them from ever proceeding to the
point where they need the catherization, and the surgery, and everything else. And that's what
people make a living off of. There is out there in the community an awareness that this is a
competition. The cardiologists would lose out."
Indeed, it's clear that to the extent that EBCT could be used for early detection, cardiologists would
likely lose some of their more profitable business to general practitioners, who could effectively
provide an early safety net of nutritional instruction and cholesterol-lowering drugs that could prevent
many people from ever developing the severe heart disease requiring expensive surgery.
Shields concurred with this analysis. "I see the cardiology community continuing to fight it. Where it's
going to be accepted is in the non-cardiology community." That means that primary physicians will
be the main users of EBCT. Shields said he that he had already advised advised many such
physicians on how to use the technology to manage their patients.
In fact, Shields suggests that the test should be used to screen all middle-aged asymptomatics. Such
screening would create cost savings, and it would also make more effective use of the existing
diagnostic technologies. He says that one cardiologist he knows had used the scan for six years and
that, as a result, he now avoids conducting invasive heart catheterization procedures on patients who
don't need it.
But based on the committee's recommendations, Arad believes that the medical community will
likely remain lukewarm on the calcium data that the test provides. Still, he thinks the EBCT scan
"will explode" over the next five years as it becomes apparent that the test can be used not just for
angiograms but for other dye-distribution tests as well. "That will overtake the whole calcium story.
And cardiologists will buy these machines not because they can detect calcium when you screen
people but because" they will allow doctors to "do all the tests in one place."
Arad thinks the scan will wipe out much of the business for the radiologists. "The first ones to jump
there and get the machines are going to control the business. There's a limited number of machines
that will be needed."
Still, the EBCT scan's ability to quantify coronary calcium seems to offer the best chance yet for
doctors to head off heart disease before it takes hold. As Shields said, "To me the data is
overwhelming. The extreme reservation about what should be done with the test. . .I don't
understand it. This is the best test we have to date."
Shields concluded with a view shared by a number of other researchers in the field. "We've got a lot
to learn, but we're not going to learn it by sticking our heads in the sand, and that's what I think the
committee has done."
As ROGUE has reported previously, however, there are reasons to doubt whether even an
unqualified AHA endorsement of the Ultrafast CT scan would lead to a genuine earnings pay-off for
Imatron, at least anytime soon. The scan, which sells for about $1.8 million, is currently in use in
about 35 mostly research-oriented facilities in the U.S., and about 65 sites worldwide. The principal
vehicle for Imatron's growth going forward, though, is HeartScan Imaging Inc., a subsidiary which
currently operates four U.S. centers where the Utrafast CT is used to assess people's risk for heart
disease.
HeartScan should prove a cash cow if successful, as it will pocket the $400 user fees for the test.
Unfortunately, to help pay for start-up costs, Imatron sold off more than 50% of HeartScan to
international investors for a relatively modest sum. Thus Imatron shareholders don't stand to benefit
as much as they might have.
Moreover, on August 14th, the company reported a four-cent loss for the second quarter versus a
one cent loss from the year before. And for the first six months of this year, the company lost seven
cents a share versus a gain of a nickel in 1995. Revenues for the quarter were down to $6.3 million
from $11.3 million during the first quarter of 1995.
With 77 million shares outstanding and a market cap of $385 million at the recent price of $5 a
share, considerable expectations already seem to be built into the stock. Indeed, the stock has risen
400% in the last year, even touching $8.37 a share in June following the publication of Dr. Arad's
paper.
Still, Imatron's story remains a curious one. Even with outstanding technology, the company's stock
may not have far to go, at least in the short-term. But even the long-term outcome is unclear, in part
because the American Heart Association may be unnecessarily impeding widespread acceptance of
the EBCT scan. It's the latter public health considerations that should concern all of us.
-- Louis Corrigan (RgeSeymour), 9/20/96
(c) Copyright 1996, The Motley Fool. All rights reserved. This material is for personal use only.
Republication and redissemination, including posting to news groups, is expressly prohibited without
the prior written consent of The Motley Fool.
Transmitted: 9/20/96 6:24 PM (media) |
