Analysis of Time Delay to Affect Thrombolytic Therapy in Patients with Acute Myocardial Infarction

ABSTRACT

BACKGROUND: Early reperfusion therapy with thrombolytic agents or primary PTCA is most important to salvage ischemic myocardium in acute myocardial infarction(AMI). Timely reperfusion of jeopardized myocardium clearly improves hemodynamics, decreases infarct size and improves survival. The extent of protection appears to be directly related to the rapidity of reperfusion after onset of coronary occlusion. Although the intravenous thrombolysis is a feasible therapy in the patients with evolving AMI, the benifit of thrombolytic therapy decreases because of the time delay after onset of symptom. This study was perfomed to analyze the factors time delay between onset of symptom and the thrombolytic therapy with retrospective and prospective questionaire in the patients with AMI. METHOD: Eighty one patients with AMI were included in this study who came to the emergency room(ER) of Chungnam National University Hospital(CNUH) from Feburary 1995 to October 1996. Delay between door and thrombolytic therapy was defined as hospital time delay. RESULTS: Thrombolytic therapy(rt-PA or urokinase iv) was done in 60 patients(74.1%) and mean prehopital time delay was significantly decreased in the patients with thrombolytic therpapy when compared with those without thormbolytic threapy(462+/-90 vs 1375+/-473 minutes, p=0.005). There were no singificant factors for prehospital time delay such as age, sex, redsidence, ER near residence, transfer time to ER near residence, family status, family history of AMI, severity of chest pain, presence of risk factors of cardiovascular disease(CVD), previous CVD, degree of education, history of other disease and routine check, transfer methods. The only 8 patients(9.8%) knew about AMI and 7 patients among these patient came to ER earlier and received thrombolytic therapy. From 57 referred patients, 40 patients(70.2%) received reperfusion therapy and only 30 patients(52.6%) had recored EKG in the referred hospital. In the analysis of hospital delay from patient's arrival to the thrombolytic therapy, the arrival time at weekdays and weekend had no differences, but hospital delay were significantly prolonged when patients arrived at ER in the night. CONCLUSION: Since prehospital time delay is a most important factor of time delay for the effective thrombolytic therapy in AMI, the pubic education program and effective transport system are needed. And routine record of EKG in patient with chest pain in the local hospital is very helpful to start effective thromolytic therapy at ER. The well designed prospective study with more patinets in our local region is essential to get more accurate information about transport system and to improve survival rate in patients with AMI.