LOS ANGELES — An intense nationwide push to speed hospital treatment for heart attack patients has been a success, cutting by 20 percent the average time people waited before getting their clogged arteries opened between 2005 and 2009.
But in a twist cardiologists called “disappointing,” the improvement did not translate into lower death rates, according to a study published in The New England Journal of Medicine.
“We had hoped this would make a huge difference, and it hasn’t,” said study senior author Dr. Hitinder Gurm, an interventional cardiologist at the University of Michigan in Ann Arbor. “We need to explore other strategies.”
Major heart attacks occur when arteries carrying blood to the heart become blocked, starving the muscle of oxygen and eventually killing heart tissue. Physicians treat heart attack patients by opening up the blood vessels, often by inserting a balloon into the vessel and inflating it to remove the blockage.
Speed is of the essence for these angioplasty procedures. As the doctors who perform them like to say, “Time is muscle.”
“The concept has always been, the faster we open the artery, the more heart muscle we can protect and the more lives we can save,” said study leader Dr. Daniel Menees, also an interventional cardiologist at the University of Michigan.
About a decade ago, the American College of Cardiology and the American Heart Association began instituting guidelines to help hospitals reduce their so-called door-to-balloon times to 90 minutes or less.
More than 1,000 hospitals eventually participated in a campaign backed by the American College of Cardiology, said Dr. John Rumsfeld, who leads the organization’s efforts to track hospital performance on heart attack care. The effort became one of medicine’s largest and most successful quality improvement projects.
Medicare began reporting which hospitals were performing well, which also encouraged medical centers to improve their door-to-balloon times, he added.
But while hospitals were clocking better times, the benefits for patients weren’t always clear-cut. Some studies seemed to show that the patients with shorter wait times were more likely to survive their heart attacks than those with longer waits. However, other research didn’t find that improved door-to-balloon times translated into lower overall death rates.
In 2010, Gurm worked on a study of 8,771 patients in Michigan that found that big improvements in door-to-balloon time didn’t translate into better survival rates. To expand on that work, the team looked at 95,007 patients admitted to 515 hospitals throughout the U.S. from July 2005 to June 2009, a period that coincided with the quality-improvement effort.
The average time it took for a patient to get treatment in a catheterization lab decreased every year, dropping from 83 minutes in 2005-06 to 67 minutes in 2008-09. But the proportion of patients who died before leaving the hospital barely changed at all, starting out at 4.8 percent and winding up at 4.7 percent.
The researchers also looked at Medicare data for a subset of 26,202 patients to see how many were alive 30 days after their procedures. Again they found no significant change in death rates, even as door-to-balloon times decreased from 88 minutes to 68 minutes.
Gurm called that additional evidence “sobering.”
He and Menees said they would like to see more attention placed on the period before a patient arrives at the hospital, a critical time when damage to heart muscle can begin to set in.
“Door-to-balloon time is really only one part of the puzzle,” Menees said.