Table 2. INOCA endotypes diagnostic criteria.

	INOCA endotypes	Pathophysiology	Diagnostic criteria
1	Microvascular anginaa	CMD	Diagnostic guidewire and Adenosine test
			FFR >0.8
			CFR <2.0
			IMR ≥25b
			HMR ≥19b
			Vasoreactivity (acetylcholine test)
			No or <90% diameter reduction
			+angina
			+ischaemic ECG changes
2	Vasospastic angina	Epicardial spasm	Diagnostic guidewire and Adenosine test
			FFR >0.8
			CFR ≥2.0
			IMR <25
			HMR <1.9
			Vasoreactivity (acetylcholine test)
			≥90% diameter reduction
			+angina
			+ischaemic ECG changes
3	Both microvascular and vasospastic angina	Both CMD and epicardial spasm	Diagnostic guidewire and Adenosine test
			FFR >0.8
			CFR <2.0
			IMR ≥25
			HMR ≥1.9
			Vasoreactivity (acetylcholine test)
			No or <90% or ≥90% diameter reduction
			+angina
			+ischaemic ECG changes
4	Non-cardiac chest pain	None	Diagnostic guidewire and Adenosine test
			FFR >0.8
			CFR ≥2.0
			IMR <25
			HMR <1.9
			Vasoreactivity (acetylcholine test)
			No or <90% diameter reduction
			No angina
			No ischaemic ECG changes
5	Non-flow-limiting CADc	Diffuse coronary artery atherosclerosis	Diagnostic guidewire and adenosine test
			FFR >0.8
			CFR ≥2.0
			IMR <25
			HMR <1.9
			Vasoreactivity (acetylcholine test)
			No or <90% diameter reduction
			No angina
			No ischaemic ECG changes
CAD: coronary artery disease; CFR: coronary flow reserve; FFR: fractional flow reserve; HMR: hyperaemic myocardial velocity resistance; IMR: index of microvascular resistance. aNon endothelial dependent microvascular angina may be diagnosed non-invasively by the methods described. bIMR and HMR values shown in table as alternative measures of microcirculatory resistance (based on thermodilution or Doppler: respectively). c<50% stenosis severity by visual assessment