WEDNESDAY, March 31, 2010 (HealthDay News) -- Who's most at risk when undergoing the common, artery-opening procedure known as angioplasty?
A major U.S. study may have come up with some answers -- risk factors that doctors can use to gauge the odds of death after angioplasty, also known as "percutaneous coronary intervention" (PCI).
"This is the largest representation of PCI practice in the country," said study co-author Dr. Sunil V. Rao, assistant professor of medicine at Duke University in Durham, N.C. "It is a nice cross-section of what is happening nationwide," he said.
The study, using data on nearly 600,000 procedures done between 2004 and 2007, found an overall in-hospital death rate of 1.27 percent. But the rate differed sharply among people undergoing angioplasty for different reasons.
For example, someone having elective (not emergency) angioplasty to prevent a possible heart attack or other cardiac problem faced a 0.65 percent risk of dying within 30 days. But the death risk was 4.81 percent -- nearly one chance in 20 -- for someone given the procedure because of a severe heart attack.
A number of other risk-predicting scores are available, Rao said, but the new one has the major advantage of being based on national experience. "It overcomes individual practice bias," he said. "Other studies have been done in single medical centers."
The journal report lists nine characteristics that influence the risk of death, starting with age and going on to such matters as previous heart failure; the presence of peripheral arterial disease (blockages in leg arteries); chronic lung disease; measures of kidney function; and the type of heart attack for which the procedure might be done.
It is not possible to look at the list and quickly assess a patient's risk, Rao said. Instead, you have to apply it to each patient's characteristics.
The study results, published April 1 in the Journal of the American College of Cardiology, can be used in several ways, Rao said. "It can be a benchmark to measure a center against other facilities," he said. "If one center's results differ markedly, you can go back and see why that is so. You want to make sure that all the factors are accounted for so that you have a level playing field."
The risk-factor assessment will be most important for someone who is advised to undergo angioplasty and is then asked to sign a consent agreement, Rao said. "This allows us to say, 'your risk is X percent,' " he said. "That allows for truly informed consent. It allows us to put an actual number on it."
On the other side, the risk-factor assessment could affect how a physician practices, Rao said. "If it is a higher-risk patient, there might be a need to change the procedure," he said. "So it can change behavior on the part of both the patient and the provider."
The new approach has two important advantages over existing PCI risk-assessment models, said Dr. Kirk Garratt, who helped develop a previous model 10 years ago at the Mayo Clinic, and who now is director of clinical research at Lenox Hill Hospital in New York City.
"First, it focuses on the risk of death," Garratt said. "Many models have looked at a composite of complications, including death. This provides pretty reliable information on the most important complication.
"Second, it is constructed from data from many hospital centers in many regions with widely different patient populations. It benefits from having drawn information from a much more varied group than used by most other studies."
However, the new measurement is not likely to be the final word on risk, Rao added. PCI techniques can change, often rapidly, so the importance of various factors may change as new information accumulates.
And the new report lists only one end point, 30-day mortality. The same data is currently being mined to determine the effect of risk factors on other end points, such as the longer-term death rate, rate of re-hospitalization and the incidence of heart attacks and other complications, Rao said. "Those data bases are in the process of being constructed," he said.
There's more on angioplasty at the American Heart Association.