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ENGLISH SUMMARYCoronary artery disease (CAD) is the leading cause of death world-wide and continues to be a major health care expense also in developed countries. It is often of significant concern when patients show symptoms of the disease, and this might be one of the reasons that only 6-12% of suspected CAD patients are diagnosed with obstructive-CAD, even after general practitioners and cardiologists have evaluated the patients. This means that a large portion of patients go through expensive and sometimes invasive testing that might be avoided through more careful pre-test risk estimation. This thesis consists of four studies, which in concert investigate the possibility to perform early risk estimation of suspected CAD patients and to safely rule-out a portion of these before proceeding to more expensive and invasive testing. The studies analyze heart sound recordings from a collection of studies performed by Acarix that in total contains more than 2500 patients. Features from heart sound analysis are used to augment an existing clinical risk model for the rule-out of healthy patients suspected of CAD.Study I established a relationship between heart sounds and clinical parameters age, sex, and BMI. Study II documented the development of a whitening filter designed to emphasize high-frequency differences in heart sounds from CAD patients. Using knowledge and methods obtained in the previous two studies, Study III investigated the spectral differences between CAD and non-CAD patients. Finally, in Study IV, acoustic features were extracted from the heart sound, and joined to an existing highperforming clinical risk model. The addition of acoustic features to the clinical risk models significantly increased the specificity from 41.5% to 48.6% while keeping the sensitivity the same 84.9%.The heart sound of patients with CAD carry information beyond what is contained in the parameters of modern clinical risk estimation models.