After-Hours MI Patients Have Longer Door-to-Balloon Waits


WASHINGTON — Door-to-balloon times are significantly longer for those whose heart attacks land them in the emergency department after regular working hours than if they arrive during a weekday, Dr. Nowwar Mustafa said at a conference sponsored by the American Heart Association.

Despite presenting at a hospital with a round-the-clock cardiac catheterization lab, night and weekend patients still experienced significant delays in receiving percutaneous coronary intervention (PCI), compared with weekday patients, said Dr. Mustafa, of Christiana Hospital, Newark, Del.

Dr. Mustafa identified three periods of crucial delay in assessing and treating patients who arrived from 7 p.m. to 7 a.m. on a weeknight or from 7 p.m. on a Friday to 7 a.m. the following Monday. “The only time in which there was no significant delay compared to weekday patients was their time to first EKG,” he said. “At every other time interval the differences were significantly longer.”

He retrospectively analyzed time delays for 893 consecutive patients who presented to the hospital's emergency department with ST-segment elevation myocardial infarction during 2002–2006. All received emergent PCI. The mean door-to balloon time was 85 minutes, and 67% of the group fell within the recommended 90-minute treatment window.

He measured four time intervals: door to first ECG; first ECG to treatment decision; treatment decision to leaving the emergency department (ED); and leaving the ED to balloon inflation.

The time to first ECG was not significantly different between those who arrived during regular hours and those who did not (9.5 minutes vs. 8 minutes). At all other intervals, patients who arrived after-hours were significantly delayed: ECG to decision, 20 vs. 16 minutes; decision to leaving the ED, 15 vs. 10 minutes; and leaving the ED to balloon inflation, 48 vs. 42 minutes.

Those delays added up, Dr. Mustafa said. The mean door-to-balloon time was significantly longer in the off-hours group (92 vs. 78 minutes). The portion of those who fell within the 90-minute treatment window was also significantly smaller (58% vs. 76%).

The hang-up appeared to be the time it took to get a cardiologist consult, he said. “During regular working hours the cath lab staff is in-house, and after working hours, the staff is on-call and ready to start the case within 30 minutes of notification. But the decision to take the patient to cath lab is made by the on-call cardiologist. During regular working hours, we have a cardiologist in-house, but this is not necessarily the case after hours.”

Dr. Mustafa will evaluate patient outcomes in these groups to determine whether the delays affected mortality.

But in a recent, separate study, delays in door-to-balloon time were associated with an increase of up to 60% in mortality (N. Engl. J. Med. 2007;356:1099–109). “The curves separated early, on the second day of hospitalization, and persisted for an entire year,” he said.

The after-hours hang-up appeared to be the time it took to get a cardiologist consult. DR. MUSTAFA

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