Although door-to-balloon times have considerably decreased across the country, the rate of in-hospital mortality among patients with ST-segment elevation myocardial infarction (STEMI) who underwent percutaneous coronary intervention (PCI) has not, according to a study published Sept. 5 in The New England Journal of Medicine.

Door-to-balloon time is now a key quality indicator and is also a determinant of institutional financial reimbursement. As a result, door-to-balloon times have decreased, the authors explained, and they sought to determine whether mortality rates followed the same trend.

“[C]urrent joint clinical practice guidelines of the American College of Cardiology and the American Heart Association (ACC-AHA) endorse a door-to-balloon time of 90 minutes or less as the goal,” explained Daniel S. Menees, MD, of the University of Michigan Health System in Ann Arbor, and colleagues.

Using a nationwide registry, the researchers analyzed data for more than 95,000 patients admitted for PCI after a STEMI at 515 sites between 2005 and 2009.

Door-to-balloon time decreased from 83 minutes between 2005 and 2006 to 67 minutes between 2008 and 2009, but in-hospital mortality rates remained virtually unchanged (4.8 percent in the first year and 4.7 percent in the fourth year). There was also no significant increase in unadjusted 30-day mortality.

“These data suggest that additional strategies are needed to reduce in-hospital mortality in this population,” the authors concluded.

Since door-to-balloon time is only a portion of the time the heart is ischemic, as the door-to-balloon time decreases, the time it takes to get to the hospital becomes more important.

“Therefore, efforts with potential to improve outcomes may include increasing patients’ awareness of symptoms, reducing the interval from the time of symptom onset to treatment, and shortening the transfer time between medical facilities,” they argued.

The authors acknowledged that one limitation of their study is its observational nature. They could not control for variables that could have impacted their results.

In an accompanying editorial, Eric R. Bates, MD, of the University of Michigan Health System and Alice K. Jacobs, MD, of Boston University Medical Center in Boston noted that same limitation, but also argued that more emphasis should be placed on reducing the time from the onset of symptoms to the first contact with a provider.

“Although it is shorter than it was several years ago, mean symptom duration is still two hours before first medical contact, and 40 percent of patients do not contact EMS,” they wrote. “Continued efforts are needed to educate patients about STEMI symptoms and about calling 911 to permit EMS triage, treatment, and transport, as STEMI teams shift their focus from in-hospital to prehospital treatment delays.”