Abstracts Category : Other

THE COMBINATION OF CARDIOVASCULAR AND GLYCEMIC BIOMARKERS FOR EARLY DECISION MAKING IN PATIENTS PRESENTING TO THE EMERGENCY DEPARTMENT WITH SYMPTOMS OF ACUTE CORONARY SYNDROME

by Colleen Shortt

Chest pain is a common presenting complaint to emergency departments (EDs) and is a symptom of serious cardiovascular events such as myocardial infarction (MI) and possibly cardiovascular death. Early decision-making regarding patient disposition is crucial for early intervention and to avoid ED congestion. The Third Universal Definition of MI states that MI diagnosis be made using electrocardiogram (ECG) findings and/or a rise and/or fall in cardiac troponin (cTn) concentrations. However, patients with ECG abnormalities represent less than 1/3 of all ACS patients, leaving the remaining to be diagnosed using multiple measurements of cTn over several hours. I therefore aimed to develop a strategy to identify patients at low-risk for major adverse cardiovascular events (early rule-out), as well as those at greatest short-term cardiac risk (early rule-in).In this thesis I present published work on the clinical utility of glycogen phosphorylase Isoenzyme BB (metabolic marker) in combination with high-sensitivity cTn (hs-cTn) to rule-out adverse cardiac events within 72hrs for patients presenting to the ED within 6hrs of ACS symptom onset. I further assessed the utility of metabolic markers using glucose in this setting. Preliminary results show that using a healthy hs-cTn concentration with a normal glucose measurement at presentation can be used to rule-out patients who present to the ED with clinical suspicion of ischemia.Further expansion of this hypothesis demonstrated that an algorithm incorporating both glucose and cTn can effectively rule-in/rule-out MI or MI/cardiovascular death in patients who present to the ED with symptoms of ACS. In addition, presentation hemoglobin A1c identified previously unknown diabetes; which may have overall health implications for these patients. I also demonstrate that using glucose in combination with cTn is a cost-effective decision-making tool in the ED as compared to cTn alone.Application of these rule-in/rule-out algorithms can improve morbidity/mortality rates, and alleviate healthcare burdens. Thesis Doctor of Philosophy (Medical Science) Myocardial ischemia is a reduction in coronary blood flow that is insufficient for heart cell demand, which can lead to myocardial injury and cell death. Acute Coronary Syndrome (ACS) encompasses three clinical presentations of myocardial ischemia: ST-elevation MI (STEMI), non-STEMI (NSTEMI) and unstable angina (UA). Current guidelines recommend using electrocardiogram (ECG) findings and multiple cardiac troponin (cTn) measurements over several hours to diagnose (rule-in) or rule-out ACS in the emergency department (ED). However, given these recommendations patients may spend several hours in the ED, consuming valuable time and resources.This project explores the use of glycemic biomarkers [e.g., glucose and haemoglobin A1c] in combination with cTn to rule-in/rule-out MI and other major cardiovascular events (MACE) to facilitate early decision-making in the ED. This thesis demonstrates that a combination of cTn and glucoseAdvisors/Committee Members: Kavsak, Peter, Medical Sciences (Division of Physiology/Pharmacology).