EW YORK (Reuters Health) – Low-risk patients with ST-segment elevation myocardial infarction (STEMI) treated with angioplasty can be discharged within 72 hours, Canadian investigators suggest.

Although STEMI patients are usually hospitalized for 5 to 7 days to monitor for serious complications, Dr. Madhu K. Natarajan and colleagues at Hamilton Health Sciences-General Site in Hamilton, Ontario, were able to safely target low-risk patients for early discharge followed by close nursing follow-up.

Within 24 hours of percutaneous coronary intervention (PCI), participants were randomized to discharge within 72 hours or standard care. Patients were eligible for the study if they had a Zwolle score of 3 or less, with no obvious contraindication to early discharge at the time of randomization.

"We find the Zwolle score particularly useful," the authors write in the January issue of the American Heart Journal. The Zwolle Primary PCI Index takes into account Killip class, postprocedural TIMI (Thrombolysis In Myocardial Infarction) flow, age, 3-vessel disease, site of infarction, and ischemic time. Patients with a score of 3 or less (out of 16) have a 30-day mortality risk of 0.5% and a 0.2% risk of malignant ventricular arrhythmias after 48 hours.

In their report, the researchers describe a prospective pilot study in 54 patients conducted from January to October 2007.

In fact, the authors found, "length of stay was short in all study patients" – a median of 55 hours overall. There was no difference between the groups either in length of stay or rate of rehospitalization at 6 weeks (8% with early discharge and 4% with standard care). No patient from either group died.

The intervention group met all prespecified criteria for feasibility, including 74% discharged within 72 hours and at least three follow-ups with the nurse, the first being within 3 days of discharge.

Among patients who could not participate in the trial because they were being transferred back to their referring hospital after PCI, the median length of stay was 78 hours (p = 0.0003). Therefore, the authors recommend, "It may be preferable to discharge these patients directly from the hospital where PCI was performed."

Am Heart J 2010;159:117e1-117e6.