Novel aspects of cardiovascular biomarkers in myocardial infarction and obstructive sleep apnea
Year: 2015
Type: dissertation
Abstract: 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.\nAim 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).\nMethods 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.\nResults 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 factors, whereas oxygen variables were observed to inherit a heterogeneous pattern of selected independent associations. The association between several of the variables of disordered breathing during sleep and inflammation was stronger in individuals with a higher body mass index (BMI).\nInterpretation and conclusion The introduction of a hs-cTnT assay enhanced NSTEMI diagnostics, but more patients will have to be considered for potentially having increased cTnT levels due to other etiologies than MI. In STEMI patients, the present findings imply that one single measurement of cTnI after PCI provides incremental information to conventional risk stratification. In individuals investigated for possible OSA, the use of S-cTnI and hs-cTnT confirmed that improved performance characteristics are broadening potential applications of cTn assays. For the diagnostic evaluation of possible OSA, the future clinical utility of all investigated biomarkers appears limited. However, the observed interaction between a higher BMI and several variables of disordered breathing during sleep may indicate activated inflammatory pathways inconsistently masked by unmeasured confounders or too moderate to be significant in this study sample. These findings expand our knowledge of the investigated biomarkers and contribute to determine their future role in patient care.
Author: Trygve Sørdahl Hall
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2288988784