Introduction
The diagnostic and therapeutic approach for patients with chronic coronary syndromes (CCS) is evolving from a simplistic approach focused on diagnosis and treatment of obstructive epicardial coronary artery disease (CAD) to include a comprehensive assessment of the functional status of the coronary circulation to assess causes of angina with non-obstructive coronary arteries (ANOCA).
ANOCA is present in 50%–70% of patients with CCS who are referred for invasive coronary angiography (ICA) and can originate from a diverse range of pathophysiological mechanisms. Invasive coronary function testing (CFT) involves additional assessment of coronary vasomotion and microvascular function to test for coronary vasomotor function disorders during ICA. Notably, when CFT is performed, underlying coronary vasomotor disorders are detected in up to 90% of patients. These disorders include impaired (microvascular) vasodilation and epicardial and/or microvascular vasospasm, reflecting functional and/or structural abnormalities of the coronary (micro)circulation. Each of these conditions has been associated with significant burden of anginal symptoms, impaired quality of life, increased risk of major adverse cardiovascular events, and substantial healthcare utilization and associated costs.
The European Society of Cardiology has recently recommended CFT for persistently symptomatic patients with ANOCA despite medical treatment (Class I, Level of Evidence B) to identify potentially treatable ANOCA endotypes and to improve symptoms and quality of life. As such CFT is typically reserved for the situation where initial medical therapy has failed and involves a second invasive procedure. However, given that 50%–70% of patients undergoing ICA have ANOCA, implementing ad hoc CFT during the initial ICA could reduce time to diagnosis without the need for ancillary invasive procedures and may lead to earlier symptomatic improvement. Both the Coronary Microvascular Angina (CorMicA) and Advanced Invasive Diagnosis for Patients with Chronic Coronary Syndromes Undergoing Coronary ANGIOgraphy (AID-ANGIO) studies previously demonstrated a high diagnostic yield of ad hoc CFT in patients presented to the catheterization laboratory for suspected CAD. The CorMicA trial additionally concluded that an ad hoc CFT approach to guide medical therapy improves quality of life in ANOCA patients, but further evidence supporting the clinical benefit of this strategy remains limited.
The ILIAS ANOCA (Inclusive Invasive Physiological Assessment in Angina Syndromes—Angina with No Obstructive Coronary Artery Disease) trial aimed to explore the clinical utility of ad hoc CFT in a multicentre setting. We hypothesized that a routine ad hoc CFT strategy, combined with a disease-specific treatment protocol, would lead to a significant improvement in quality of life among patients with ANOCA compared with standard care. Additionally, we proposed that routine ad hoc CFT would be both feasible and safe in routine clinical practice, offering an effective means of providing an early and comprehensive diagnosis.
