Invasive Endotyping in Patients With Angina and No Obstructive Coronary Artery Disease: A Randomized Controlled Trial

Area of Science:

• Cardiology
• Diagnostic Imaging
• Clinical Trials

Background:

• Angina in patients with non-obstructive coronary arteries (INOCA) presents a diagnostic challenge.
• Invasive coronary function testing (ICFT) is explored to identify underlying causes like microvascular dysfunction or vasospasm.
• Coronary computed tomography angiography (CCTA) is used for initial assessment.

Purpose of the Study:

• To evaluate the diagnostic utility of ICFT in patients with INOCA.
• To assess the impact of ICFT-guided diagnosis on angina burden and treatment satisfaction.

Main Methods:

• Prospective screening of outpatients undergoing CCTA.
• Invasive endotyping including coronary angiography, fractional flow reserve, coronary flow reserve, index of microvascular resistance, and acetylcholine provocation.
• Randomized assignment to disclosure or non-disclosure of ICFT results to the invasive cardiologist.
• Primary outcome: reclassification rate of initial diagnosis. Secondary outcomes: Seattle Angina Questionnaire and Treatment Satisfaction Questionnaire.

Main Results:

• Of 231 patients, 76.5% in the intervention group received a diagnosis of coronary vasomotor disorder compared to 47.4% in the control group (OR 4.05, P<0.001).
• No significant difference in Seattle Angina Questionnaire summary scores between groups at 6 and 12 months.
• Global treatment satisfaction was significantly higher in the intervention group at 12 months (P=0.013).

Conclusions:

• Invasive functional assessment in INOCA patients improves diagnostic accuracy for coronary vasomotor disorders.
• While ICFT does not reduce long-term angina burden, it enhances patient treatment satisfaction.
• ICFT plays a role in optimizing management strategies for INOCA.