The role of coronary reactivity testing in women with no obstructive coronary artery disease

Two-thirds of women with signs and symptoms of ischemia and no obstructive coronary artery disease (INOCA) have abnormal coronary reactivity. These women are challenging to assess, diagnose and manage because of a lack of evidence-based guidelines. Furthermore, they are considered to be at 'low risk' by most physicians, often receive no specific therapy and tend to be dismissed from subspecialty care.

Coronary reactivity testing (CRT) is considered the reference-standard for evaluation of epicardial and microvascular coronary function in response to various vasoactive agents. It provides a comprehensive vascular function assessment for diagnosis, a guide for management, and has prognostic benefit that outweighs the risk of the procedure. We recently demonstrated the prognostic value of assessing coronary vascular reactivity in women with signs and symptoms of ischemia, especially those with no obstructive coronary artery disease.

Invasive CRT is a feasible, useful method to identify coronary microvascular dysfunction (CMD) and risk stratify women with INOCA. It has a comparable safety record with other invasive procedures. Future research is directed at optimizing patient selection, streamlining of invasive CRT methods using user-friendly catheters to enhance feasibility in the routine clinical setting, and optimizing treatment protocols, with clinical trials designed to evaluate outcomes.