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Strong association found between the use of diagnostic
testing and subsequent invasive cardiac procedures
Patients who undergo coronary stress testing (treadmill tests)
are more likely to undergo subsequent coronary angiography, and
similarly, patients who have angiography are more likely to
undergo a revascularization procedure such as angioplasty or
coronary artery bypass graft (CABG) surgery. This association
between testing and subsequent therapeutic procedures reflects
underlying uncertainties about when to test for and treat
ischemic heart disease, according to a study supported in part by
the Agency for Health Care Policy and Research (HS06813).
David E. Wennberg, M.D., M.P.H., of the Maine Medical Assessment
Foundation, and his colleagues analyzed procedure data for all
Medicare beneficiaries in northern New England (Maine, New
Hampshire, and Vermont) who were treated in 12 coronary
angiography service areas in 1992 and 1993. They calculated total
stress tests (imaging and nonimaging), coronary angiography, and
revascularization procedures. Slightly more than half of the
12,553 Medicare patients who had an imaging stress test
subsequently underwent coronary angiography (7,117), and nearly
half (3,874) of those who had angiography later underwent
These findings suggest that the decision to test is remarkably
close to being a decision to treat, according to the researchers.
They point out that this cascade of events is more likely to
occur when there are differences of opinion about which
interventions are appropriate. The researchers conclude that
local diagnostic intensity is a critical link to the risk of
therapeutic interventions in coronary heart disease.
Details are in "The association between local diagnostic testing
intensity and invasive cardiac procedures," by David E. Wennberg,
M.D., M.P.H., Merle A. Kellett, M.D., John D. Dickens, Jr., and
others, in the April 17, 1996 Journal of the American Medical
Association 275(15), pp. 1161-1164.
Physicians vary by specialty in their use of
treatments for patients with end-stage disease
Cardiologists are the least likely physicians to withhold or
withdraw life sustaining treatment for their patients, and when
presented with hypothetical cases, they are more aggressive in
their recommendations for such treatment. Oncologists, on the
other hand, are more apt to withhold treatment than other
physicians and more willing to recommend withholding treatment
for the same hypothetical cases.
These differences most likely are due to the lessons the
physicians have learned from the practice of their specialties.
Cardiologists may view cardiopulmonary resuscitation (CPR) and
intensive care favorably because they work well for patients with
acute heart disease. On the other hand, cancer patients are
unlikely to survive CPR, and oncologists have learned to be
conservative in recommending its use, according to researchers at
the University of North Carolina at Chapel Hill.
In a study supported in part by the Agency for Health Care Policy
and Research (HS06655), they interviewed 158 physicians who cared
for hospitalized patients with end-stage congestive heart
failure, chronic obstructive pulmonary disease (COPD), cancer, or
cirrhosis of the liver to assess the physicians' thresholds for
use of specific life-sustaining treatments. The researchers then
followed up to determine which decisions were made regarding use
or withholding of CPR, ventilator support, or intensive care.
Overall, physicians recommended CPR and ventilator support for
patients with end-stage congestive heart failure or COPD if the
chance for survival was at least 48 percent, but they required a
predicted survival of at least 74 percent for patients with
cancer. Cardiologists recommended CPR if the patients with
end-stage heart or lung disease had a 30 percent or better
likelihood of survival, but other physician groups required a 44
percent to 58 percent probability of success. Oncologists
recommended CPR for patients with metastatic cancer if their
probability of survival was 82 percent, compared with 58 percent
for cardiologists. In practice, cardiologists were least likely
to issue orders to withhold treatment and most likely to use
life-sustaining treatments for patients with end-stage
The researchers conclude that physicians vary in their
willingness to use and in the actual use of life-sustaining
treatments, and some of this variation is explained by specialty
training. They suggest that efforts to change end-of-life care
may be more successful if they include physicians as well as
patients and that educational interventions in fellowship
programs might help to ensure that all physicians learn similar
approaches to end-of-life decisionmaking.
More details are in "Who decides? Physicians' willingness to use
life-sustaining treatment," by Laura C. Hanson, M.D., M.P.H.,
Marion Danis, M.D., Joanne M. Garrett, Ph.D., and Elizabeth
Mutran, Ph.D., in the April 8, 1996, Archives of Internal
Medicine 156, pp. 785-789.
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