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People with severely clogged coronary arteries coupled with other serious
health problems lived longer if they underwent surgery to bypass the blocked
vessels rather than less-invasive percutaneous procedures to reopen them, new
Cleveland Clinic research shows. Full results of the study were published in the
May 18, 2004 Circulation.
For the study, Cleveland Clinic researchers examined five-year mortality
rates in a group of patients with high-risk characteristics, such as coronary
artery disease in multiple heart vessels coupled with diabetes, high blood
pressure or heart failure.
Patients who had percutaneous coronary interventions (PCI), such as
angioplasty or stenting, to reopen clogged arteries had mortality rates nearly
two times greater than patients who had coronary artery bypass grafting (CABG)
surgery. CABG surgery restores blood flow to heart tissue by taking a healthy
vein or artery from the leg, arm, or chest and moving it outside the heart to
bypass the clogged coronary vessel. In PCI, cardiologists typically gain access
to the heart’s clogged vessels by snaking slender tubes and instruments into
and up through the femoral artery (the initial incision is made in the groin).
Using a specially outfitted catheter, the cardiologist can then widen a narrowed
artery and even prop it open with a mesh tube called a stent.
Reaping benefit from results
The study results were somewhat surprising in light of recent technological
and medical advancements in PCI, which is considered significantly less invasive
than open-heart surgery, said Sorin J. Brener, M.D., one of the study
co-authors.
"Bypass surgery tended to have a greater benefit in the sickest
patients," said Dr. Brener, Cleveland Clinic staff cardiologist.
"Particularly if they contradict conventional wisdom, surprising results
are beneficial to patients because they help guide us in targeting treatment
options that can help optimize care."
Investigators reviewed the medical records of more than 5,100 patients who
had CABG and more than 870 who had PCI. All patients were treated at The
Cleveland Clinic between 1995 and 1999. Although overall survival rates were not
significantly different between the two groups, researchers found important
differences after adjusting for certain risk factors, for instance diabetes,
hypertension, smoking, body weight and other factors.
The one- and five-year mortality rates were 5 percent and 16 percent,
respectively, for the PCI treatment group, and 4 percent and 14 percent for the
CABG treatment group. After adjusting for additional risk factors, PCI was
associated with significantly higher death rates in all categories.
Clinic expertise likely plays a role
Study investigators noted several points to consider in light of these
findings. First, the Cleveland Clinic’s operative mortality rates for these
procedures are significantly lower than national averages calculated by Society
of Thoracic Surgeons (STS), which has data on more than 100,000 cardiovascular
surgeries. So the same study performed at another center might reach different
conclusions. The Cleveland Clinic’s in-hospital mortality rate is 1.1 percent,
whereas the national rate reported by STS is 3.3 percent. In addition, compared
with CABG, PCI is likely to be the better treatment for lower-risk heart disease
patients because of its shorter recovery time, less-invasive nature and lower
blood loss.
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