Methods to optimise the diagnosis and management of acute coronary syndromes: Biomarkers, antithrombotic agents, and thromboinflammatory responses

Introduction: Despite advances in diagnostics and interventional therapies in acute coronary syndromes (ACS), key uncertainties persist. This thesis investigates complementary diagnostic and therapeutic approaches across the ACS pathway, aiming to improve precision and safety in clinical decision making.
Methods: Four studies were conducted. Study 1 was a prospective biomarker study including 25 participants with angiographically confirmed coronary artery disease (CAD) and 15 controls without CAD, evaluating exercise-induced changes in glycosylated apolipoprotein J (ApoJ-Glyc) as a potential early ischaemia biomarker. Study 2 was an observational substudy examining high sensitivity troponin (hsTn) kinetics during exercise testing in patients with non-thrombotic occlusive CAD compared with controls, aiming to refine interpretation of stress related troponin elevation. Study 3 was a prospective registry of 634 opioid-treated patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI), comparing enoxaparin with unfractionated heparin (UFH) ± glycoprotein IIb/IIIa inhibitors (GPI), focusing on thrombotic and bleeding outcomes during index admission.
Study 4 was a prospective observational study assessing thromboinflammatory responses in 12 patients undergoing coronary artery bypass grafting (CABG) before and after cardiopulmonary bypass (CPB).
Results ApoJ-Glyc showed a modest post-exercise decline in CAD patients with no significant difference versus controls (A2 p=0.22; A6 p=0.43). Post exercise hsTn levels increased significantly in CAD patients compared with controls (p< 0.01). Enoxaparin demonstrated comparable thrombotic (p=0.35 and 0.53) and bleeding outcomes (p=0.2 and 0.55) to UFH ± GPI. Following CABG, ADP-induced platelet aggregation significantly decreased after CPB (p=0.01), alongside marked neutrophil activation (CD11b, p< 0.001).
Conclusions ApoJ-Glyc lacks diagnostic utility for early myocardial ischaemia. HsTn is highly sensitive but risks overdiagnosis in non-thrombotic occlusive CAD. Enoxaparin appears safe during PPCI in opioid-treated STEMI. CPB induces transient platelet desensitisation with a pronounced inflammatory response. These hypothesis-generating findings support further large, multicentre validation studies.