Percutaneous coronary intervention (PCI) is a common procedure to treat coronary artery stenoses. Several studies had demonstrated that PCI does not reduce the risk of death or myocardial infarction when performed to patients with stable angina. However it has been observed that most patients believe that PCI will reduce their risk for death and myocardial infarction. On the other hand, cardiologists generally acknowledge the limitation of PCI according to the current literature.Cardiologists' decision to refer a patient to PCI is based on factors other then perceived benefits such as fear of missing a needed procedure, defensive medicine, desire of demonstrating their professional competence, vested professional and economic interests, accomplish patient expectation, the so called oculo-stenotic reflex, when a lesion is dilated regardless the clinical indication. Patients' misleading perception of harm and benefits of a procedure is mainly related to the cognitive dissonance, when individuals tend to reduce the conflict of an uncomfortable decision adopting information, which are likely to reduce their discomfort. Furthermore, patients believe that doing more means doing better, that technologic intervention are better than pharmacological treatment that in turn are better than doing nothing. Finally, they assume that a procedure is really effective since their physician suggested it.It should be emphasized that physicians and patients do not communicate successfully about key decision and how little we know about patient understanding of the factors that influence important medical care decisions. Although considerable attention is given to facilitating informed consent, patients' perceived benefits of elective PCI do not match existing evidence, as they overestimated both the benefits and urgency of their procedures. These findings suggest that an even greater effort at patient education is needed prior to elective PCI to facilitate fully informed decision-making.