Hospitals specializing in emergency angioplasty show best results

January 18, 2006

Patients in need of emergency coronary artery angioplasty fare better when treated at a hospital that performs the procedure around the clock than at one that offers angioplasty part time, according to a study in the Jan. 17 issue of Circulation.

Patients in need of emergency coronary artery angioplasty fare better when treated at a hospital that performs the procedure around the clock than at one that offers angioplasty part time, according to a study in the Jan. 17 issue of Circulation.

A team led by University of Michigan and Yale University cardiologists found that patients receive faster treatment and are less likely to die during their hospital stay if they have their emergency angioplasty at a hospital where it is the default treatment used on most patients suffering acute myocardial infarction.

By contrast, delayed treatment and the risk of in-hospital death were both higher for patients treated at a hospital where emergency angioplasty was used in a minority of MI patients. Patients were significantly more likely to die before leaving the hospital, and they waited an average of 20 minutes longer for treatment than those treated at a hospital where most heart attack patients received angioplasty. Many waited far longer than the 90-minute window during which emergency angioplasty is thought to have an edge over fibrinolytics.

Researchers evaluated the records of 37,233 patients who were treated at 463 hospitals divided into four categories: The most specialized group performed emergency angioplasty on more than 88.5% of MI patients. The least specialized group provided emergency angioplasty to fewer than 34% of their heart attack emergency patients. The other two groups fell in between.

The biggest difference in survival and time-to-treatment for angioplasty patients was seen between the highest and lowest groups. A noticeable, though not statistically significant, difference existed between the highest group and the next two groups. There were no significant differences among the groups in death risk or treatment time for patients given fibrinolytic drugs.

All of the patients had suffered a form of heart attack known as ST-elevation MI, and all had arrived at the hospital within 12 hours of the start of their symptoms. None was transferred from an acute-care hospital or had conditions that would have kept them from getting either angioplasty or fibrinolytics.

Surprisingly, the study suggests that a hospital's level of specialization in emergency angioplasty has more to do with patient survival than does the sheer number of emergency angioplasties performed there each year. Previous studies have shown that patients do better when they receive angioplasties and other such treatments at hospitals where many such procedures take place each year.

"In the case of emergency angioplasty, for hospitals it seems that it's not just how many you do, but how used to doing them you are," said lead author Dr. Brahmajee Nallamothu, an assistant professor of internal medicine at the U-M Medical School. "The overall commitment to doing emergency angioplasties, and the protocols and staffing that come out of that commitment, appear to be key."

Hospitals where the default emergency treatment for acute MI is fibrinolytics may want to focus on optimizing that approach or determine better ways to institute emergency angioplasty protocols and staffing for around-the-clock care, according to the study.

Nallamothu noted that public policy can also play a role. Michigan has recently required that hospitals newly licensed to perform emergency angioplasty without onsite cardiac surgery be able to do it 24/7.

The study was funded by a National Heart, Lung, and Blood Institute grant and used data from the National Registry of Myocardial Infarction (NRMI) collected from 2000 to 2002.

Funding for the NRMI study that yielded the data was provided by Genentech, which makes two fibrinolytic drugs used to treat acute MI. The company provided access to the NRMI data at no charge and approved the study protocol before the analysis.

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