Non-Invasive Coronary Functional Evaluation of Patients With Single-vessel Coronary Artery Disease

Persistent or recurrent angina after successful percutaneous coronary intervention (PCI) remains a common clinical problem, affecting approximately 20-30% of patients despite complete epicardial coronary revascularization. Coronary microvascular dysfunction (CMD) has been proposed as a potential mechanism underlying persistent symptoms and abnormal functional testing after PCI, but it is still unclear whether CMD develops as a consequence of the PCI procedure or represents a pre-existing condition associated with coronary artery disease. The NICE-CAD-PCI study is a prospective, single-center study designed to investigate coronary microvascular function in patients with stable single-vessel coronary artery disease treated with PCI. Specifically, the study will compare coronary microvascular function in the left anterior descending coronary artery (LAD) territory between patients undergoing PCI of the LAD and patients undergoing PCI of a different coronary artery (right coronary artery or left circumflex artery). This approach aims to clarify whether impaired coronary microvascular function is limited to the treated vascular territory, suggesting a PCI-related effect, or is also present in non-treated territories, supporting the hypothesis of a pre-existing generalized microvascular abnormality. Within four weeks after PCI, all participants will undergo a comprehensive non-invasive coronary functional evaluation using transthoracic Doppler echocardiography (TTDE) to assess coronary blood flow velocity in the LAD during hyperventilation, cold pressor, and dipyridamole stress tests. Coronary flow reserve and coronary flow responses to the different physiological stimuli will be evaluated as markers of coronary vascular function. Participants will be followed for six months after PCI to assess the occurrence of clinically driven target lesion revascularization and major adverse cardiovascular events. The study will also explore whether abnormalities detected by non-invasive coronary functional testing are associated with restenosis or adverse clinical outcomes. The findings of this study may improve the understanding of the mechanisms responsible for persistent symptoms after PCI and contribute to the identification of patients with coronary microvascular dysfunction who may benefit from tailored diagnostic and therapeutic strategies.

Inclusion Criteria: * Invasive coronary angiography and PCI performed within the previous 4 weeks from enrollment; * Obstructive single-vessel CAD (\>75% coronary diameter reduction or fractional flow reserve \