Novel insights into the complexity of ischaemic heart disease derived from combined coronary pressure and flow velocity measurements

This thesis concerns the complexity of ischaemic heart disease, and the crucial role of the coronary microcirculation in its diagnosis and prognosis. After five decades of a stenosis-centered approach towards both its diagnosis and treatment, it is increasingly acknowledged that ischaemic heart disease is a complex disease that involves multiple levels of the coronary circulation, including both the epicardial and microvascular domains of the coronary circulation, as well as the myocardium. This multi-level origin of ischaemic heart disease has important implications for routine physiology-guided strategies applied in contemporary clinical practice, as is discussed in Part A of this thesis.
Despite a well-documented benefit of physiology-guided coronary revascularization compared with angiographic guidance, its application in clinical practice remains limited. This has governed attempts to optimize the applicability of coronary physiology techniques in clinical practice by circumventing part of the practical ambiguities associated with physiological testing. One of such approaches, circumventing the need for pharmacological vasodilation, is discussed in Part B of this thesis.
Finally, the acknowledgement of the coronary microcirculation as an important prognostic component in ischaemic heart disease has governed attempts to identify the magnitude of its prognostic value, as well as to design novel therapeutic strategies that specifically address the coronary microcirculation, which is discussed in Part C of this thesis.