Cardiovascular diseases are the most common cause of death in many countries, especially in Iran . Coronary artery disease (CAD) is the leading cause of cardiac diseases in Iran. It usually happens in people aged the 70s, but nowadays, the prevalence of cardiac events has been raised up to 45% in middle-aged people (aged 40s and 50s) .
ST-Elevation Myocardial Infarction (STEMI) is a severe type of heart attack during which one of the heart's main arteries is occluded. The ST-segment elevation is an abnormality detected on the 12-lead ECG. This sudden disturbance in blood flow can be due to an obstructing thrombosis caused by erosion, fissuring, or dissection. Platelets gathering can form thrombus in the vessel and thus cause stenosis [3, 4]. Sometimes it can block blood flow completely [5, 6]. The pain usually occurs when myocardial demand for oxygen gets higher, and blood flow is insufficient for this demand .
Several medications are used for the treatment of myocardial infarction (MI). To name some, there are beta-blockers, statin, aspirin, P2Y inhibitor, and nitroglycerin . Antiplatelet medication choice can be affected by previous percutaneous coronary intervention (PCI) or fibrinolytic treatments. According to recent trials, ticagrelor and prasugrel are shown superior to clopidogrel and are preferred in patients with a history of PCI, [9, 10] but clopidogrel should be prescribed in patients who are undergoing fibrinolytic therapy . Sometimes the plaque ruptures and the diagnosis of STEMI is made by ECG changing and troponin rising, and symptoms cannot be controlled with medications. The golden time to perform PCI in PCI-capable hospitals is 90 minutes, or if not, the patient should be transferred to a PCI-capable hospital in 120 minutes . Thrombolytic therapy should be started for the patient in the first 30 minutes of patient's presentation in the hospital if PCI is unavailable within 120 minutes of first medical contact . The goal of thrombolytic therapy is to remove life threatening clots in blood vessels, facilitate blood flow, and protect the tissues and organs from being damaged. Thrombolysis can be performed by injecting clot-dissolving drugs using an intravenous (IV) line or using a long catheter to deliver the thrombolytic agent to the blockage site. The clot can also be removed or broken physically using a long catheter with an attached mechanical device to the catheter’s tip . Indication for thrombolytic therapy in emergencies is to dissolve clots in the main arteries of the heart, brain, and lungs . PCI is a non-surgical procedure that involves a combination of angioplasty with stenting and is used to treat narrowing of the heart's coronary arteries. In this procedure, femoral or arterial arteries are used to access the bloodstream. Then X-ray imaging is used to determine the path of coronary arteries and the exact site of blockage. After that, a coronary angioplasty can be done to relieve the narrowing of coronary arteries using balloon catheters or keep them open using stents. CABG (coronary artery bypass grafting) involves replacing the stenotic arteries with grafted vessels from elsewhere in the body. PCI can be an alternative to CABG, but in some instances, CABG may be superior [15, 16].
To evaluate the cardiac performance, usually, Ejection fraction (EF) and stroke volume (SV) are measured in emergency rooms or cardiac care unit (CCU). However, SV and EF do not always change in parallel and are affected differently by changes in cardiac load .
EF is defined as the percentage of the ejected blood to diastolic volume during ventricular contraction. Echocardiography is used to determine EF in the CCU, which usually is about 55% for LV . In patients with acute STEMI who have undergone P-PCI and thrombolysis, the objective is to enhance the blood flow to ischemic sites as well as preserving the quality and quantity of the patient's life .
Previous studies have released controversial results. Some of them demonstrated no significant difference in mortality rate and re-hospitalization of patients who underwent PCI with those who received thrombolytic therapy [19–21]. However, some studies showthat PCI is superior to thrombolytic therapy according to long-term outcomes .
To determine the prognosis in patients with STEMI, left ventricular ejection fraction (LVEF) is a reliable predictor of clinical outcomes; therefore, we aimed to compare the mortality rate, re-hospitalization, and ejection fraction of smoker patients who underwent PCI with those who received thrombolytic therapy in Ayatollah Taleghani and Labbafinejad hospitals of Shahid Beheshti University of Medical Sciences, Tehran City, Iran, in autumn 2018.