Comparison of Official Hours versus Non-Official Hours: Percutaneous Coronary Intervention in Acute ST-Elevation Myocardial Infarction Patients
Suphot Srimahachota MD*, Smonporn Boonyaratavej MD*, Wasan Udayachalerm MD*, Wacin Buddhari MD*, Jarkarpun Chaipromprasit MD*, Taworn Suithichaiyakul MD*
Affiliation : * Cardiac center and Division of Cardiology, King Chulalongkorn Memorial Hospital
Background : Percutaneous coronary intervention (PCI) is now a favorable treatment for acute ST elevation
myocardial infarction (STEMI). However, in non-official hours (non-OH), this modality of treatment has a
questionable outcome because of the treatment delay.
Objective : To compare the outcomes of PCI during official hours (OH) with non-OH in acute STEMI patients.
Materials and Methods : A prospective consecutive registry of PCI in acute ST-elevation MI patients at King
Chulalongkorn Memorial Hospital from May 1999 to December 2003 were analyzed. Kaplan Meier survival
analysis was used to determine the in-hospital mortality. Multivariate analysis was used to determine the
prognostic factors for in-hospital mortality.
Results : Two hundred and fifty six consecutive patients (OH-107, non-OH-149) who underwent PCI for acute
STEMI were enrolled. Their mean age (61.9 + 12.2 vs 60.6 + 12.8 y, p = ns), male gender (73.8% vs 73.2%, p
= ns), history of diabetes (30.2% vs 33.8%, p=ns), severity of the patients (percent of patients in Killip IV –
22.4 vs 21.5, p = ns), ejection fraction (48.7 + 15.1 vs 45.9 + 14.7, p = ns), cardiopulmonary resuscitation prior
PCI (15.0% vs 14.2%, p = ns), anterior MI (55.1% vs 51.0%, p = ns) were similar in both groups. Hypertension
was slightly less common (39.6% vs 52.7%, p = 0.04) but smoking was more common (62.6% vs 49.0%, p =
0.03) in OH group. Door to balloon time and decision to balloon time were significantly shorter in the OH
group than the non-OH group (67.9 + 47 vs 119.6 + 83 min, p < 0.001 and 60.8 + 35 vs 98.3 min, p < 0.001).
However, the total delayed time was not statistically significantly different (402 + 316 vs 424 + 215, p = 0.55).
Angiographic success rate was achieved in 98.1% for the OH group and 94.7% in the non-OH group (p = ns).
In-hospital mortality rate was 10.3% and 10.7% respectively.
Conclusion : The door to balloon time for PCI in acute STEMI patients in the non-OH group was longer than
the OH group; however, the total delayed time was not different. The in-hospital mortality rate was similar.
Keywords : Primary percutaneous coronary intervention, ST-elevation myocardial infarction, Official hours, Non-official hours
