Principles and pitfalls in coronary vasomotor function testing

BACKGROUND Coronary vasomotor dysfunction can be diagnosed in a large proportion of patients with angina in the presence of non-obstructive coronary artery disease (ANOCA) using comprehensive protocols for coronary vasomotor function testing. Although consensus on diagnostic criteria for endotypes of coronary vasomotor dysfunction have been published, consensus on a standardised study testing protocol is lacking. AIMS In this review we provide an overview of the variations in coronary vasomotor function testing used and discuss the practical principles and pitfalls of coronary vasomotor function testing. METHODS For the purpose of this review we assessed study protocols that evaluate coronary vasomotor response as reported in the literature. We compared these protocols regarding a number of procedural aspects and chose six examples to highlight the differences and uniqueness. RESULTS Currently, numerous protocols co-exist and vary in vascular domains tested, the manner to test these domains (e.g. pre-procedural discontinuation of medication, provocative agent, solution, infusion time, and target artery) and techniques used for measurements (e.g. doppler vs thermodilution technique). CONCLUSIONS This lack of consensus on a uniform functional testing protocol hampers both a broader clinical acceptance of the concepts of coronary vasomotor dysfunction, and the widespread adoption of such testing protocols in current clinical practice. Furthermore, the endotype of coronary vasomotor dysfunction might differ between the few specialised centres that perform coronary vasomotor function testing as a result of the use of different protocols. In this review we provide an overview of the variations in coronary vasomotor function testing used and discuss the practical principles and pitfalls of coronary vasomotor function testing.