May 26, 2005
Study favors bypass surgery over angioplasty
The New England Journal of Medicine yesterday published the findings of a large-scale study that indicate that angioplasty -- an increasingly popular invasive procedure for patients with blocked coronary arteries -- carries a higher risk of death over the long term than open-heart bypass surgery. The researchers were led by Edward L. Hannan, chairman of the Department of Health Policy Management and Behavior at the University at Albany School of Public Health.
The study is particularly significant because it raises questions regarding the shift in treatment for blocked coronary arteries over the past decade or so -- the shift away from coronary bypass surgery in favor of angioplasty, which involves sliding a balloon into an artery through a small incision and then propping it open with a wire-mesh stent.
Inasmuch as angioplasty procedures require a far shorter recovery time and lower risk of in-hospital complications than bypass surgery, it is currently performed more than one million times a year in the U.S., which is about three times the rate of bypass operations. Bypass surgery generally costs between $25,000 to $35,000 while angioplasties run from around $10,000 to $15,000.
The study involved a review of almost 60,000 patients from 1997 through 2000 with serious heart disease in two government databases in New York state. Researchers concluded that those with three blocked arteries who received stents were 1.56 times as likely to die within three years as those who had bypass surgery. Similarly, those with two blocked arteries who got stents were 1.33 times as likely to die as those who had bypass surgery. Finally, over a third of the angioplasty patients required either surgery or additional stents within three years, while only 5% of the bypass surgery patients required either angioplasty or further surgery within the same period. The researchers note that the study does not include findings on the newer generation of drug-coated stents, which some cardiologists believe will improve the outcome for angioplasty.
This large scale study adds to an increasing number of smaller studies finding advantages of bypass surgery over angioplasty for long-term survival. Last year, a Cleveland Clinic study that followed 6,000 patients found that the risk of death over time was more than twice as high in the angioplasty group of relatively high-risk patients.
Both the Cleveland Clinic and New York studies involved review of registry data and not the controlled clinical trials that scientists consider the best form of evidence. In registry studies, researchers must adjust existing data for various factors, which can lead to debate and criticism over the effect such adjustments have on the ultimate findings of the study. Nevertheless, registry data studies allow the reearchers to involve much larger patient groups than clinical trials and to evaluate medical practices that are being most commonly performed in the medical marketplace.
Posted by Tom at May 26, 2005 5:10 AM |
On the surface, this study seems to favor Coronary Artery Bypass Grafting (CABG) over Percutaneous Transluminal Coronary Angioplasty (PTCA).
However, the patients who had improved survival after CABG had extensive and diffuse disease:
- All 3 coronary arteries with 70% blockage (or more) with involvement of the proximal Left Anterior Descending artery (LAD). The LAD supplies blood for the anterior wall of the left ventricle, and is the "Southwest Freeway" equivalent of coronary blood flow, compared to the other two vessels, which might be represented by "Bissonett Avenue".
- 70% blockage of 2 of the 3 coronary arteries, but also involving the LAD, either proximally or more distally.
These are patients who traditionally would have been received recommendations for CABG surgery. It is only recently that Cardiologists have begun to "plasty" patients with 3 vessel disease, primarily because it is such an "easy" procedure (relative to CABG). It also takes business away from the Cardiovascular Surgeons, who do the CABG's.
Please note that one of the authors of the NEJM article is Wayne Isom, a CV Surgeon originally from West Texas who gained his 15 minutes of pop fame by doing CABG on David Letterman. While Dr. Isom is a leader in his field, you have to be a little careful when a surgeon recommends that surgery is better than the other treatments available. Remember the truism "If all you have is a hammer, the whole world looks like a nail."
What I find most interesting about the study is the data about repeat procedures after initial CABG or PTCA. 27% of patients who had PTCA ended up having another "plasty" within 3 years, where only 8% of folks undergoing CABG had a "plasty" in the same time frame. To me, this speaks more about the negative reinforcement that CABG offers than how successful a procedure it might be.
As a General Internist who does neither PTCA or CABG, I have a standard routine I follow for patients of mine who get some form of coronary revascularization. As they lie in bed, recovering from the procedure, I tell them, "OK, you just got a plumbing job to open up your pipes. Now we've got to go to work to keep those new pipes from clogging up like the old ones did." I have found that persons who have had their chest cracked open like an oyster shell are much more receptive to suggested changes in diet and life style than those who have only had a catheter inserted into their femoral artery. PTCA may be a little too non-invasive and too "easy" to be a factor in getting people to effect significant change, like stopping smoking, eating better, and getting regular exercise.....
Posted by: jim bob baker at May 26, 2005 8:57 AM
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