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Coronary Computed Tomographic Angiography in Patients Suspected of Stable Angina Pectoris A Clinical and Methodological Evaluation

 

Kristian Altern Øvrehus

Summary

Coronary CT angiography (CTA) has emerged as a useful diagnostic tool and is increasingly usedfor the evaluation of patients with suspected coronary artery disease (CAD). Technicaladvancements during the last decade have enabled 3-dimensional evaluations of the tortuous andconstantly moving coronary arteries by coronary CTA permitting assessment of atheroscleroticchanges affecting the coronary artery lumen and vessel wall. A number of studies havedemonstrated its high diagnostic accuracy for detection and exclusion of significant CAD inpatients with suspected CAD. However, most of these studies derived from highly experiencedcenters. The growing body of evidence has also suggested that coronary CTA may performfavorably to other traditional non-invasive diagnostic methods in the evaluation of patients withsuspected CAD, however, limited prognostic data have hampered the enthusiasm for its use as afrontline diagnostic test.The objectives of this PhD thesis was to evaluate1. The diagnostic performance of coronary CTA in a center with limited experience (Paper I)2. The diagnostic performance of coronary CTA compared to exercise testing in patients withsuspected CAD (Paper II)3. The frontline use of coronary CTA in patients with suspected stable angina and its influenceon patient management and outcome (Paper III).4. The interscan, interobserver and intraobserver reproducibility of coronary artery plaquedetection by low-radiation dose high-pitch spiral acquisition coronary CTA (Paper IV).The main results demonstrate that coronary CTA by 64-SCT or DSCT in a center with limitedexperience initially has a suboptimal diagnostic accuracy for detection and exclusion ofsignificant CAD, and that a high diagnostic performance requires a large number of caseinterpretations using state-of-the-art scanner technology. Coronary CTA seems to performfavorably compared to traditional functional testing in patients with low to intermediate pretestlikelihood of significant CAD, hence has the potential to reduce the number of unnecessary ICA in comparison to current standards. In similar patients a frontline coronary CTA influencespatient management without resulting in excessive additional testing. Furthermore, coronaryCTA provides valuable prognostic information with an excellent intermediate term outcome inpatients with a normal scan. Finally, a high interscan, interobserver and intraobserverreproducibility for coronary plaque or calcified plaque detection was demonstrated using therecently introduced low-radiation dose high-pitch spiral acquisition coronary CTA protocol insymptomatic patients of intermediate risk. However, the fair to moderate reproducibility fornon-calcified plaques and the variability in semi-quantitative plaque burden estimationunderscore that low radiation dose coronary CTA plaque imaging remains challenging.