DOI: https://doi.org/10.53350/pjmhs22161530 ORIGINAL ARTICLE 530 P J M H S Vol. 16, No.01, JAN 2022 The Frequency of Early Subacute Stent Thrombosis after Primary Percutaneous Coronary Intervention in Patients with St-Segment Elevation Myocardial Infarction SANAULLAH SHAIKH 1 , VASHU MAL 2 , JAGDESH KUMAR 3 , SUHAIL AHMED 4 , FARAZ FAROOQ MEMON 5 , BILAWAL ADRANI 6 1,2 Postfellow intervention cardiology, NICVD 3 Consultant Interventional Cardiologist, Memon medical institute hospital karachi 4 Interventional Fellow, Nicvd Karachi 5 Senior Registrar, National Institute of Cardiovascular Diseases Hyderabad Satellite 6 Clinical fellow, NICVD ABSTRACT Introduction: Acute coronary syndrome(ACS) is associated with activation ofplateletsand thecoagulationsystem which could influence the incidence of early stentthrombosis(EST).Stent thrombosis is a relatively uncommon phenomenon, yet it is a serious complication which often presents as an ST-segment elevation myocardial infarction (STEMI) and/or sudden cardiac death 1,2 .Stent thrombosis (ST) is an uncommon but life-threatening complication after percutaneous coronary intervention (PCI), frequently manifesting as acute coronary syndrome (ACS) or even cardiac death.Platelet activation and the heightening of the coagulation system play a major role in the pathogenesis of acute coronary syndrome (ACS) and might impact the occurrence of stent thrombosis in those patients who undergo stenting during ACS. Unfortunately, stent thrombosis (ST) is more frequent after stenting for STEMI than after elective stenting with both drug-eluting stents (DES) and baremetal stents (BMS). Objective: To determine the frequency of early subacute stent thrombosis after primary percutaneous coronary intervention in patients with STsegment elevation myocardial infarction Methodology: Study Design: Descriptive Case Series Setting: This study was conducted in NICVD Hospital, Karachi Subjects and Methods: Study was approved by hospital ethical review committee. All patients who fulfilled the inclusion criteria were included in the study. Pre-operatively a written consent was taken from each patient by the primary investigator of this study. All these patients were undergone primary PCI and stent either drug-eluting stents (coated with medication) or bare-metal stent was placed. These patients were observed for 24 hours for early subacute stent thrombosis. All the collected data were entered into the proforma attached at the end. Results: Mean ± SD of age was 55.56±12.24 with C.I (53.52------57.59) years. Mean ± SD duration of surgery was 33.48±9.26 with C.I (31.90------35.05) minutes. Out of 142 patients 103 (72.53%) were male and 39 (27.4%) were female. Frequency of early subacute stent thrombosis was found to be 4(2.82%). Conclusion: It is to be concluded that frequency of early acute stent thrombosis after primary PCI was found to be 2.82%.Patients presenting with STEMI who are hemodynamically unstable and have multivessel coronary disease undergoing coronary stenting during ACS, are at increased risk of EST. Keywords: Acute myocardial Infarction, Primary PCI, Early Subacute Stent, Thrombosis, STEMI INTRODUCTION Stent thrombosis (ST) is the most feared complication of coronary stent treatment because of its morbidity and mortality. Subacute thrombosis (SAT) is a major concern in patients undergoing percutaneous coronary intervention (PCI). One of the major concerns remaining in the treatment with stenting of patients with acute myocardial infarction (AMI) is the occurrence of stent thrombosis (ST). Early subacute ST is reported to occur with an incidence ranging from 0.5–2.0 % 1-3 . These early events may be related to lesion-related and procedural factors such as edge dissection, residual thrombus or tissue protrusion, compromised flow, stent under expansion or a combination of these. 4-5 Stent thrombosis (ST) is an uncommon but life- threatening complication after percutaneous coronary intervention (PCI), frequently manifesting as acute coronary syndrome (ACS) or even cardiac death. The use of coronary stents has become the preferred therapy with primary percutaneous coronary intervention (PCI) for ST- segment elevation myocardial infarction (STEMI). This is based on data showing that stents have been able to reduce ischemicdriven target vessel revascularization and angiographically documented restenosis and re-occlusion. 6 Unfortunately, stent thrombosis (ST) is more frequent after stenting for STEMI than after elective stenting with both drug-eluting stents (DES) and bare-metal stents (BMS). 7-8 In other different studies, early subacute stent thrombosis after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction was reported as 5.3% 9 , 62% 10. Primary percutaneous coronary intervention (PCI) for treatment of ST-segment elevation myocardial infarction (STEMI) has significantly improved clinical outcome as compared with thrombolytic therapy. 11 Stent thrombosis (ST) is a recognized complication occurring in 0.5% to 2.2% of patients with coronary artery disease treated by percutaneous coronary intervention (PCI) with stent implantation. 12,13 Its occurrence is expected to increase with the number of stents in particular drug-eluting stent (DES) implantation procedures