Factors Associated with Delay in Thrombolytic Therapy in Patients with ST-Elevation Myocardial Infarction

Treatment delay in the management of ST-elevation myocardial infarction conversely correlates with prognosis and survival of the patients. This study aimed to investigate factors associated with delay in the thrombolytic therapy of these patients in Tehran.

Between 2007 and 2010, the interval between the self-reported time of the onset of symptoms and initiation of the thrombolytic agent in 513 patients with a diagnosis of acute ST-elevation myocardial infarction was recorded. Medical history and socio-demographic characteristics of the patients treated within two hours after the onset of symptoms and patients treated after two hours from the onset of symptoms were compared, and the odds ratios were calculated using logistic regression.

The mean age of the patients was 61.2 (SD = 11.1) years, and 76% of the patients were male. The median time between the onset of symptoms and treatment was 158 (SD = 30.4) minutes. Mean for decision time was 61 (SD = 19), which was responsible for 83% of the entire treatment delay. The mean transportation time was 34 (SD = 12) minutes, and the median door-to-needle time was 44 minutes. Odds ratio for history of diabetes mellitus was 1.90 (95% CI: 1.26-2.87), for hypertension was 1.55 (95% CI: 1.08-2.23), and for prior coronary heart disease was 1.47 (95% CI: 1.17-1.84).

The most important factor associated with delay in treatment was decision time. Improving emergency medical services dispatch time, obtaining pre-hospital electrocardiograms for early diagnosis, and pre-hospital initiation of thrombolytic therapy may reduce the delay time.