Coronary stent loss is a rare but potentially catastrophic complication of percutaneous coronary intervention (PCI), particularly during complex procedures involving calcified lesions and bifurcations. We report the case of a 74-year-old man undergoing PCI of a subacutely occluded proximal left anterior descending artery, complicated by stent dislodgement following an involuntary deep inspiration by the patient. The stent became partially detached from the delivery balloon and was successfully moved into the radial artery while remaining over the guidewire. A stepwise bailout strategy allowed safe completion of the coronary intervention via secondary access, followed by successful snaring and retrieval of the lost stent. This case highlights the importance of maintaining wire position, procedural patience, and structured problem-solving in managing rare but high-risk intraprocedural complications.

Acute and Chronic Coronary Syndromes represent two major medical challenges and are the leading cause of cardiovascular mortality and morbidity. While Chronic Coronary Syndrome (CCS) can be defined as the whole group of structural and/or functional abnormalities involving coronary arteries before and after an acute event, Acute Coronary Syndrome (ACS) encompasses the condition of acute myocardial ischemia (with or without consequent myocardial injury and troponin release) due to dynamic mechanisms such as athero-thrombosis or vasospasm. Because of this complex interplay between structural and functional mechanisms arising from both the epicardial and microvascular compartments, a comprehensive approach to fully investigate the whole spectrum of coronary disease is therefore essential. To address this issue, the invasive functional assessment has evolved through the years, from a way to guide revascularization to a meticulous protocol for characterizing ischemia-leading mechanisms and stratifying prognosis both in ACS and CCS. However, coronary physiology remains underused in clinical practice, and multiple gaps in knowledge still exist; on top of this, there is increasing heterogeneity regarding how to perform functional assessment, with different protocols proposed by various centers. The aim of this review is to summarize the evidence in the field of coronary physiology, and to discuss how and when to use it at its best.