Characterization of Different Phenotypes of Microvascular Dysfunction and Their Impact on Angina Severity in Patients With Chronic Angina in the Absence of Obstructive Coronary Artery Disease.

The aim of the present study will be to identify different phenotypes of microvascular dysfunction and their associations with the severity of anginal symptoms assessed through the Seattle Angina Questionnaire(SAQ-7).

Inclusion Criteria:Patients who meet all of the following criteria will be considered for study participation:Age ≥18 and <85 years. Chronic coronary syndrome (including patients with anginal equivalents) Angina CCS class II-IV Evidence of inducible reversible ischemia in noninvasive trialsAvailability of the following measurements:Microvascular resistance index (IMR)Quiescent full cycle flow ratio (RFR),fractional flow reserve (FFR),Coronary flow reserve (CFR) Willingness to participate and sign the informed consent document prior to the procedure.Exclusion Criteria:At least one of the following:Pregnancy or breastfeeding. Medical or psychological conditions that would compromise proper and orderly participation.Left ejection fraction less than 30% Prior coronary artery bypass surgery (CABG) Decompensated congestive heart failure (CHF) Chronic or acute renal failure with creatinine >2mg/dl Severe valve disease Patients with comorbidities limiting life expectancy to less than one year.