Scoring system predicts risks of heart procedure
CHICAGO (Reuters) - A new scoring system may help doctors and patients get a better handle on the potential risks of undergoing a common procedure to open blocked heart arteries, U.S. researchers said on Wednesday
Researchers at the Mayo Clinic in Rochester, Minnesota, developed a seven-point scale to predict a patient's risk of dying from angioplasty or percutaneous coronary intervention (PCI), which involves inserting and inflating tiny balloons into vessels to widen narrowed arteries.
The scale uses information that typically can be gathered in a patient interview such as age, gender, the incidence of heart attack, cardiac shock, kidney failure, diabetes or heart failure, to arrive at a risk score.
Prior scales have relied on information that could be gathered only through a diagnostic exam known as a coronary angiography, an X-ray of the inside of heart arteries that is done by threading a narrow tube through blood vessels leading to the heart and injecting a special dye that creates a picture of the vascular system.
By then, the patient is often already sedated and the doctor is ready to go ahead and finish the job by inflating a tiny balloon in the vessel and opening up the blockage.
"That is not the best time to tell the risk to the patient," Mayo's Dr. Mandeep Singh, who helped develop the scale, said in a telephone interview.
Singh and colleagues created the scale based on data gathered at Mayo, but to test its accuracy, they used data on 309,351 patients in a large national database who had undergone PCI between 2004 and 2006.
They plugged patient information into their formula to calculate the predicted probability of death and compared this to how the patients actually fared.
Initially, the model tended to underplay the risks, but they were able to correct this problem.
The retooled scoring system proved highly accurate at predicting which patients in the database died from their procedure. The model correctly predicted about 88 percent of the problem procedures.
"Anything above 75 percent is considered good," said Singh, whose research was published in the journal Circulation: Cardiovascular Interventions.
He said having an accurate assessment of a patient's risk before the procedure can help doctors better plan treatment and better advise patients in advance of PCI.
If widely adopted, Singh thinks the scale could also be used to assess hospital and individual physician quality by comparing patients' predicted scores with the actual outcome of the procedure.
U.S. doctors performed more than 1.3 million PCIs in 2005, according to the American Heart Association.
(Editing by Will Dunham and Eric Walsh)
