Novel aspects of cardiovascular biomarkers in myocardial infarction and obstructive sleep apnea

• Main Author: Hall, Trygve Sørdahl
• Format: Dissertation
• Language: English

Background In contemporary clinical practice, measurement of circulating biomarkers is an integral part of patient care. Biomarkers have many areas of application and provide diagnostic, prognostic and therapeutic information. The appropriate use of biomarkers can facilitate the understanding of underlying pathophysiological processes and may contribute to improved management of various disease states. Aim The aim of this thesis was to explore novel aspects of circulating biomarkers associated with cardiovascular disease, with an emphasis on myocardial infarction (MI) and obstructive sleep apnea (OSA). Methods In a retrospective, national, single-center, pre-post comparison study of hospital admissions, changes in non-ST-segment elevation myocardial infarction (NSTEMI) diagnostics after the implementation of a high-sensitivity cardiac troponin T (hscTnT) assay were examined. In a post hoc analysis of patients with acute ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) who participated in a prospective, international, multi-center, randomized placebo-controlled trial, the utility of cardiac troponin I (cTnI) variables for prediction of clinical outcomes and cardiac function during three months followup were investigated. In a national, single-center, cross-sectional study of individuals examined for possible OSA, circulating levels of several biomarkers (myocardial stress; single-molecule cTnI [S-cTnI] and hs-cTnT, inflammation; myeloid-related protein-8/14 and C-reactive protein) and their associations to variables of disordered breathing during sleep were explored. Results An increase of primary NSTEMI admissions after the implementation of a highsensitivity assay was observed, while a higher proportion of the subjects did not have pathological findings on coronary angiography and fewer had significant dynamic cTnT changes. In patients with STEMI, cTnI levels were associated with an increased risk of clinical events and decreased cardiac function at three months independent of clinical risk factors. Furthermore, cTnI significantly improved discrimination of patients with and without endpoint. In individuals investigated for possible OSA, the application of novel cardiac troponin (cTn) assays facilitated estimation of myocardial stress in all subjects. No independent associations between apnea-hypopnea index and myocardial stress or inflammation were found after adjustment for other risk facto