Clinical applications of stress cardiovascular magnetic resonance imaging in ischemic heart disease

Abstract

Ischemic heart disease (IHD) remains the leading cause of death worldwide. Although the global mortality rate of in patients with IHD has achieved a successful decrease, new issues have been raised meanwhile. The understanding of IHD has experienced the tremendous changes. For example, coronary microvascular disease (CMD) has been included as the subtype of IHD in addition to epicardial coronary artery disease (CAD). In the clinical setting, up to 90% patients with stable chest pain have been found without overt coronary stenosis, and they may have CMD. However, poor clinical prognosis and reduced life quality have been well recognized in patients with CMD. However, this condition remains poorly understood. Stress cardiovascular magnetic resonance imaging (CMR) has emerged as a promising tool to detect CAD with satisfactory diagnostic accuracy reaching to over 90%, showing non-inferior capability, compared with other cardiac imaging modalities. The stress application of CMR has been extended to CMD studies for its unique advantage in myocardial perfusion quantification. In this thesis, the coronary microcirculation function is investigated in a retrospective cohort of 199 patients with stable chest pain but free of obstructed coronary arteries, linking with clinical factors to explore the underlying mechanisms from an imaging perspective. Furthermore, the prognostic value of stress perfusion CMR in the area of CMD is determined. The result shows a high prevalence of coronary circulation dysfunction occurring in 81% symptomatic patients without epicardial CAD. Cardiovascular risk factors may contribute to CMD development, especially hypertension. 15.6% adverse clinical events happened during a median follow-up of 5.8 years in this cohort. CMR-derived myocardial perfusion reserve index (MPRI) is an independent predictor for CMD patients, and subjects with MPRI <1.4 have a 2.5-fold increased risk. This study analyses 10-year follow-up prognostic data of CMD aiming to better understand this disease and provides novel information to guide clinical management of CMD in future.