DALLAS, June 3 -- "Practice makes perfect," the old adage goes. Nowhere is it more true these days, new research suggests, than in America's hospitals which perform balloon angioplasty, the increasingly popular non-surgical technique to reopen clogged heart arteries and to prevent heart attacks.
Two new studies published in the June 3 issue of the American Heart Association journal Circulation indicated that fewer procedures per physician translate into more complications including death, heart attack and emergency surgery. The procedure involves making a small incision, usually in the groin, where a balloon-tipped tube is threaded through blood vessels to the site of a blockage in a diseased heart artery. The balloon inflates, flattening the fatty material and restoring blood flow.
"These new data, tying annual physician case volume to patient outcome cannot be ignored. The implications for patient care are obvious, and it is now up to the cardiology community to react to the new findings," says Paul S. Teirstein, M.D., in a commentary accompanying the studies, which the researchers describe as among the first to look at the angioplasty outcome by tapping great data bases that include tens of thousands of patients.
Teirstein, director of interventional cardiology at the Scripps Clinic in La Jolla, Calif., describes what might be called a "score card" for angioplasty doctors as one approach to informing the public about the relationship between complication rate and the number of procedures a doctors performs.
Major complication rates were 9.3 percent for patients treated by doctors who performed fewer than 70 angioplasties a year versus only 2.9 percent of patients whose doctors handled more than 270 of the procedures. The study examined 12,985 angioplasties by 38 physicians at five major medical centers in 1993 and 1994.
This is a "highly significant" 69 percent reduction in major complications, even after adjustments for differences in patients' disease, report the researchers, led by Stephen G. Ellis, M.D. of the Cleveland Clinic, Cleveland.
In a second analysis in today's Circulation, James G. Jollis, M.D., associate professor of medicine at Duke University Medical Center, Durham, N.C., found that more than half of the physicians and one-fourth of the hospitals they studied were unlikely to have met minimum patient volume guidelines issued by the American Heart Association and the American College of Cardiology.
Senior citizens whose angioplasties were performed by the low-volume doctors had significantly worse outcomes, as shown by higher rates of emergency bypass surgery performed to overcome problems, the Duke investigators report. Low-volume hospitals also had higher death rates among angioplasty patients. Data included some 97,000 Medicare patients.
The AHA/ACC guidelines, first published in 1988, called for physicians to perform a minimum of 50 angioplasties a year to maintain competency. In revised guidelines issued in 1992, the two organizations raised the recommended minimum number of procedures to 75.
Ellis and his co-authors, noting that adverse consequences for patients were "significantly and inversely related" to the number of angioplasties done, whether adjustments were made for differences in risk or not, conclude: "Physician-to-physician differences in angioplasty outcome appear to be large enough so that it may be useful to develop individual physician profiles."
While a score card for angioplasty performers sounds appealing, "the devil is in the details," Teirstein comments in his editorial. He believes the concept has several major limitations: Complication rates between high- and low-volume performers are statistically difficult to compare, he says, and methods for correcting for differences in risk are imperfect and do not "enjoy widespread confidence among practicing physicians." Score carding in some high-risk cases has led to denial of care or the transfer of riskier cases to out-of-state hospitals, he adds.
Much of the problem reflected in these new studies, Teirstein says, relates to paradoxical shifts in angioplasty technology. "Coronary angioplasty has become both more simple and more complex." New techniques include use of stents, tiny "Slinky"-type coils inserted into diseased vessels to prop them open, as well as new clot-deterrent drugs (called glycoprotein inhibitors) that help keep new blockages from forming in the treated arteries. As a result, the number of patients that have to be rushed to emergency bypass surgery has recently declined.
These new "tricks of the trade" have made it easier for inexperienced doctors to be more successful handling routine angioplasties, Teirstein says. But at the same time, the advances have made it tempting for them to treat patients with more serious disease not previously treatable -- including complicated blood vessel blockages that involve hard-to-handle calcified deposits in vessels. Thus there's added risk for less experienced angioplasty performers.
"An inexperienced operator is more likely to achieve an excellent result when undertaking a straightforward procedure but is less likely to succeed if [angioplasty] is more complex or if unexpected complications arise," he says. "Exponential" growth in new technology will only widen this experience gap, Teirstein predicts. What can be done about this?
The relationship between patient volume and angioplasty outcome should be continually monitored, he says. And a new certification process for interventional cardiologists that will be coordinated by the American Board of Internal Medicine should be "vigorously pursued." Further, Teirstein recommends that a new notification process be set up to make information on physician caseload readily available.
And with technology used in angioplasty growing more complex even as the procedure itself becomes more commonplace, experts predict this "experience gap" will only widen.
"I believe we have a responsibility to our patients to set up a mechanism that, at a minimum, ensures that patients have access to these new data," he writes.
About 404,000 angioplasty procedures were done in 1994 in the United States, according to the most recent figures available from the American Heart Association.
Co-authors with Ellis are William Weintraub, M.D.; David Holmes, M.D.; Richard Shaw, Ph.D.; Peter C. Block, M.D.; and Spencer B. King III, M.D.
Jollis's co-authors include Eric D. Peterson, M.D., M.P.H.; Charlotte L. Nelson, M.S.; Judith A. Stafford, M.S.; Elizabeth R. DeLong, Ph.D.; Lawrence H. Muhlbaier, Ph.D.; and Daniel B. Mark, M.D., M.P.H.
Circulation is one of five journals published in Dallas by the American Heart Association.
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Media advisory: Dr.Teirstein can be reached in La Jolla by calling (619) 554-9905. Dr. Ellis can be reached in Cleveland by calling (216) 286-8916. Dr. Jollis can be reached in Durham by calling (919) 286-8747. Reporters may call (214) 706-1173 for copies of the reports and editorial. (Please do not publish telephone numbers.)
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