Backround: The current guidelines recommend complete revascularization during the initial procedure for Non-ST Elevation Acute Coronary Syndrome (NSTE-ACS) with multivessel disease (Class IIa), or a functional evaluation of non-infarct-related artery (non-IRA) severity (Class IIb). Recent trials have demonstrated that in ACS patients with multiple affected vessels, Fractional Flow Reserve (FFR)-guided selective percutaneous coronary intervention (PCI) in the non-IRA is superior to routine PCI in the non-IRA, leading to reduced rates of death, myocardial infarction (MI), and repeat revascularization. FFR accurately assesses coronary lesions but is invasive and entails risks and expenses. The exercise stress test (EST) is a safe, and cost-effective method for evaluating coronary artery disease. The Duke treadmill score (DTS), a prognostic indicator, interprets EST data. We planned to examine the correlation between EST and DTS, with FFR.

Methods: This prospective study included patients undergoing revascularization for ACS with an additional borderline stenosis. FFR measurements were scheduled after 30 days post ACS. Asymptomatic patients during this period underwent an EST. The study assessed the correlation between EST parameters (DTS) and FFR measurements in this subgroup.

Results: Seventy-eight eligible patients participated. EST parameters and FFR measurements correlated significantly. DTS, treadmill angina index, and FFR measurements also showed significant relationships (p=0.007, p<0.001, respectively).

Conclusion: Non-invasive, simple, and safe EST data, including DTS, could be a viable alternative to FFR procedures. This approach, especially useful in low-income countries with rising Non-NSTE-ACS cases, offers a cost-effective diagnostic method, and minimizing the need for PCI and stents.