It is an observational study which objective is to analyze, through a series of invasive parameters, the state of the coronary microvasculature immediately after the successful percutaneous coronary intervention of a chronic total occlusion and at 6 months after the index procedure.

The aim of the study is to check the variation in the values of the index of microcirculatory resistance (IMR) and invasive absolute coronary flow (AF). The working hypothesis is that, in the follow-up of these patients, AF will increase significantly with respect to its baseline and, conversely, IMR will be reduced during the follow-up.

Inclusion Criteria:

• Those patients with a clinical indication for percutaneous coronary intervention of a chronic total occlusion. As a routine clinical practice in our center, it is proposed to perform a angiographic follow-up 6 months after the index procedure.

Exclusion Criteria:

• No specific exclusion criteria.

Patients with ischemic heart disease and evidence of at least one chronic total occlusion, with data of inducible ischemia and/or viability and susceptible to percutaneous coronary intervention.