Invasive Diagnosis of Coronary Functional Disorders Causing Angina Pectoris

Coronary vasomotion disorders represent a frequent cause of angina and/or dyspnoea in patients with non-obstructed coronary arteries. The highly sophisticated interplay of vasodilatation and vasoconstriction can be assessed in an interventional diagnostic procedure. Established parameters characterising adequate vasodilatation are coronary blood flow at rest, and, after drug-induced vasodilation, coronary flow reserve, and microvascular resistance (hyperaemic microvascular resistance, index of microcirculatory resistance). An increased vasoconstrictive potential is diagnosed by provocation testing with acetylcholine or ergonovine. This enables a diagnosis of coronary epicardial and/or microvascular spasm. Ischaemia associated with microvascular spasm can be confirmed by ischaemic ECG changes and the measurement of lactate concentrations in the coronary sinus. Although interventional diagnostic procedures are helpful for determining the mechanism of the angina, which may be the key to successful medical treatment, they are still neither widely accepted nor applied in many medical centres. This article summarises currently well-established invasive methods for the diagnosis of coronary functional disorders causing angina pectoris.