Door-to-balloon time has dropped dramatically as hospitals rush heart attack patients into treatment, but a five-year study released last week shows quicker hospital care has not saved more lives.
Heart attacks are a medical emergency and hospitals race against the clock to open the clogged artery causing the attack, and restore blood flow.
Door-to-balloon time is the amount of time between a heart attack patient’s arrival at the hospital to the time he or she receives an intervention, such as a balloon angioplasty, to open the artery.
The study published in the Archives of Internal Medicine showed no change in mortality, in spite of the drops in the median door-to-balloon time at Michigan hospitals from 113 minutes in 2003 to 76 minutes in 2008.
“Considerable effort had focused on reducing door-to-balloon time with the assumption that quicker care translates into a significant reduction in mortality,” says study senior author Dr. Hitinder Gurm, clinical assistant professor of internal medicine and an interventional cardiologist at the Cardiovascular Center.
“When we looked at our data, the reduction in door-to-balloon time was dramatic. However, to our surprise and dismay, we found the number of patients who died had not changed,” Gurm says.
The Cardiovascular Center and colleagues at Michigan hospitals tracked the outcomes of 8,771 patients with acute ST-elevation myocardial infarction, commonly known as a severe heart attack.
Current American Heart Association and American College of Cardiology guidelines recommend getting these patients into treatment in 90 minutes or less.
By the end of the study period, nearly 70 percent of Michigan patients received care in the recommended door-to-balloon time. The study examined whether patients did better because of it.
“Our results suggest that a successful implementation of efforts to reduce door-to-balloon time has not resulted in the expected survival benefit,” says Dr. Anneliese Flynn, a resident in the Department of Internal Medicine, and lead author of the trends study.
In-hospital mortality remained unchanged at about 4 percent.
“The obvious next question is should we stop worrying about door-to-balloon time? I think that would be wrong,” Gurm says. “My concern is that door-to-balloon time is only one part of the delay that a patient has from the time their symptoms start to the time the artery is opened.
“We need to do a better job at educating patients and developing systems of care so that patients get to the hospital quicker and not only worry about the time involved once they hit the hospital door.”
Although door-to-balloon time dropped, the study showed no improvement in the time between the onset of symptoms such as chest pain, and when patients arrived at the hospital.
“It could be that the negative impact of the increased symptom-to-door time among high risk patients is sufficient to mask any potential protective effect of the decreased door-to-balloon time,” Flynn says.
Data on trends in door-to-balloon time came from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium.
Additional U-M authors are Dr. Mauro Moscucci, University of Miami, formerly of U-M; Dr. David Share, Department of Family Medicine; and Dean Smith, Cardiovascular Center.
