Importance of Delayed Perfusion with Primary Angioplasty on Short-Term Mortality in Acute Myocardial Infarction Patients
Khanat Kruthkul MD, MSc*, Suphot Srimahachota MD*, Wasan Udayachalerm MD*, Wacin Budhari MD*, Jarkarun Charipromprasit MD*, Taworn Suitthichayakul MD*, Chitr Sitthi-amorn MD, MSc, PhD*
Affiliation : * Division of Cardiovascular Disease, Department of Medicine, King Chulalongkorn Memorial Hospital, Bangkok
Background : Early primary coronary interventions (PCI) in acute ST elevation myocardial infarction (STEMI)
is associated with improved outcome and mortality rate but delayed reperfusion especially after 6 hours is still
doubtful in terms of clinical benefits because most myocardial muscle are infarcted after 6 hours of onset of
chest pain.
Objective : The aim of the present study was to compare the mortality rate of patients treated with PCI within
6 hours of symptom onset to those treated between 6 to 24 hours after the onset of STEMI.
Materials and Methods : The present study included consecutive patients from the data of the Fast Track Registry
of King Chulalongkorn Hospital from June 1, 1999 to October 31, 2003 to compare the thirty-day mortality of
patients treated with early or delayed PCI (0-6 hours vs. 6 -24 hours after symptom of chest pain) for STEMI.
Results : Two hundred and sixteen patients who underwent PCI were enrolled. Male gender (82% vs. 64.9%,
p = 0.03) and history of smoking (72.1% vs. 50%, p = 0.04) were predominant in the early treatment group
(ETG) vs. the delayed treatment group (DTG). Mean age (60.5% vs. 61.03%, p = 0.11), diabetes (31.4% vs.
29.7%, p = 0.82), hypertension (64.0% vs. 54.1%, p = 0.20), dyslipidemia (58.1% vs. 60.8%, p = 0.73), and
ejection fraction < 40% (22.8% vs. 32.0%, p = 0.625) were similar in both groups. There were no differences
in angiographic finding and hospital management. Door to balloon and total delay time were 124.13 +
143.27 min and 407.94 + 268.183 min, respectively. The thirty-day mortality (9.01% vs. 12.76%, p = 0.379)
and 1 year mortality (12.4% vs. 16.9%, p = 0.532) were not significantly determined by Log rank test in both
groups. As for cardiogenic shock, ETG tended to have a lower thirty-day mortality than DTG but no statisti-
cally significant difference (12.5% vs. 50.0%, p = 0.0809).
Conclusion : The delayed PCI up to 24 hours in STEMI does not increase short-term mortality at thirty days;
therefore, it may still have benefit in STEMI patients. However, it tended to have higher short-term mortality
than early PCI especially in cardiogenic shock but showed no statistical significance.
Keywords : Acute ST-elevation myocardial infarction (STEMI), Percutaneous coronary intervention (PCI), Delay reperfusion
