Cardiac Troponins in Critical Illness

Abstract

Troponin elevations are frequent during critical illness and associated with higher short-term mortality. Whether troponin elevations in that population independently confer a worse prognosis remains a matter of debate and how to manage patients with troponin elevations in the intensive care unit is unknown. Myocardial injury after noncardiac surgery is a well-defined entity, but can the same criteria be applied in patients who transition in the intensive care unit? Most patients present a troponin elevation early after coronary artery bypass surgery. How should a myocardial infarction be defined in these patients? This thesis comprises 7 chapters that inform these knowledge gaps. Chapter 1 is an introduction providing the rationale for conducting each of the included studies. Chapter 2 reports on the PROTROPIC pilot study evaluating the feasibility of a larger study to assess whether troponin elevations in critical illness independently predict mortality. Chapter 3 presents the use of secondary cardiovascular prevention medications and cardiac risk stratification in the PROTROPIC pilot study participants. Chapter 4 is a systematic review and meta-analysis of randomized controlled trials evaluating the efficacy and safety of statins in critically ill patients. Chapter 5 describes patients admitted to the intensive care unit after noncardiac surgery in the VISION cohort. This substudy also evaluates whether admission to the intensive care unit modifies the prognosis associated with myocardial injury after noncardiac surgery. Chapter 6 evaluates the prevalence and prognosis associated with different definitions of myocardial infarction after coronary artery bypass grafting using data from the CORONARY trial. Finally, Chapter 7 discusses the conclusion, limitation, and implications of the research presented in this PhD thesis.