Comprehensive COROnary PHYSiology Assessment in Patients With Angina With Nonobstructive Coronary Arteries - CZECH Republic (CoroPhys-CZECH)

Two mechanisms are primarily involved in the pathophysiology: structural and functional impairment, which can affect both epicardial and microcirculatory arteries and may also be combined. Thus, from a clinical point of view, two basic endotypes are distinguished in ANOCA: 1) microvascular angina (MVA) due to structural damage of microcirculation (coronary microvascular dysfunction - CMD), or functional microvascular vasospasm (angina and ECG changes without epicardial vasospasm on acetylcholine testing) and 2) epicardial vasospastic angina (VSA) - angina, ECG changes and vasospasm on acetylcholine testing (Table 1).

1. Microvascular Angina (MVA) (FFR > 0,80, iFR > 0,89)

• coronary microvascular dysfunction (CMD) (CFR < 2,0 (2,5), MRR < 2,1, IMR > 25)
• microvascular vasospasm (angina + ECG changes + < 90% epicardial spasm during Ach testing)

2. Vasospastic Angina (VSA) (angina + ECG changes + > 90% epicardial spasm during Ach testing)
3. Non-coronary chest pain (negative thermodilution and Ach testing)

Table 1 - ANOCA endotypes. FFR - fractional flow reserve, iFR - instantaneous wave-free ratio, CFR - coronary flow reserve, MRR - microvascular resistance reserve, IMR - index of microcirculatory resistance, EKG - electrocardiogram, Ach - acetylcholine.

The clinical manifestation of ANOCA includes a wide range of symptoms that reduce the quality of life and are often misdiagnosed, mistreated, and not infrequently, leading to repeated hospitalizations and invasive investigations. At the same time, patients with both MVA and VSA have a poorer long-term prognosis. Direct assessment of the response of the coronary microcirculation to vasodilator stimuli and diagnosis of vasomotor abnormalities are crucial for accurate stratification and selection of treatment strategies for patients with ANOCA, resulting in reduced angina severity and improved quality of life compared to standard care. Comprehensive invasive coronary functional testing (CFT) is currently the only diagnostic method to establish a definitive diagnosis and characterize a specific ANOCA endotype, supported by professional societies' current recommendations.