the use of pressure wires is the standar of care to evaluate angiographically intermediate coronary lesions, however, limitations in the management of these type of lesions continue to be a challenge for the interventional cardiologist. The use of FFR has some limitations such as the use of adenosine due to its cost, adverse effects (e.g. transient atrioventricular block, angina, headache, etc.), time consuming and some relative contraindications for its use. In this sense, in recent years new rest indices (iFR, RFR, dPR) and hyperemic indices without adenosine (cFFR-NTG, Pd/Pa-NTG or cFFR) have been developed, demonstrating an improvement in terms of outcomes with its use, so they can also be used as a tool to guide us to plan our strategy. These new indices, particularly the cFFR-NTG, are simpler, at least as safe and have an excellent correlation with the FFR with adenosine in the assessment of intermediate coronary lesions.

In recent years, functional assessment after intervention has also been increasingly implemented, which, like intracoronary imaging, can make us change our attitude and correlate with the prognosis. The lower implementation of this practice, especially in multivessel patients, may result from having to lose the position of the wire to check equalization, difficulty in crossing the wire, wear/breakage of the material after diagnosis (2-3 vessels), use more time and contrast, etc. These problems could be reduced, at least partially, with the use of the workhorse coronary guidewire pressure microcatheter to measure post-PCI functional assessment. Although the usefulness of post-PCI FFR has been demonstrated, there is no clearly established cut-off value (0.84-0.96) and it seems that in reality the values are a continuum of risk so that the higher the value, the better the prognosis . Furthermore, other simpler indices such as rest or hyperemic indices without adenosine have not been correlated with FFR in post-PCI.

The purpose of this study is to evaluate the correlation between cFFR-NTG and other indices taking FFR as a reference in multivessel patients after undergoing intervention. Establish cut-off points and correlate it with adverse cardiovascular events (MACE) in a 1-year clinical follow-up.

Percutaneous coronary intervention (PCI) is a standard treatment strategy for coronary artery disease (CAD). With the presence of myocardial ischemia, PCI reduces the risks of death, myocardial infarction (MI), and revascularization compared to medical therapy. However, the risk of future clinical events remains high, and about 10% of patients experienced further cardiovascular events after PCI. Facing intermediate coronary lesions the use of pressure wires is the standar of care, however, limitations in the management of angiographically intermediate coronary lesions continue to be a challenge for the interventional cardiologist. The measurement of fractional flow reserve (FFR) to determine the hemodynamic relevance of coronary stenosis has been shown to be a technique that improves the prognosis and cost-efficiency of the procedures when compared to visual angiographic interpretation alone. Due to this evidence, the use of FFR to guide interventional procedures is a class I recommendation in current clinical practice guidelines.

Patients with multivessel coronary artery disease are another field in the use of pressure guiding. In these patients, the use of FFR has demonstrated the reclassification of the severity of coronary lesions in up to 40% of cases, modifying the number of functionally significant lesions and making it possible to reorient therapeutic decisions, avoiding interventional treatment of non-significant lesions and with a better prognosis.

However, the use of FFR has some limitations such as the use of adenosine due to its cost, adverse effects (e.g. transient atrioventricular block, angina, headache, etc.) and time consuming. In addition, the presence of atrioventricular block, asthma or severe chronic obstructive pulmonary disease are relative contraindications for its use. In this sense, in recent years new rest indices (iFR, RFR, dPR) and hyperemic indices without adenosine (cFFR-NTG, Pd/Pa-NTG or cFFR) have been developed , demonstrating an improvement in terms of outcomes with its use, so they can also be used as a tool to guide us to plan our strategy. These new indices, particularly the cFFR-NTG, are simpler, at least as safe and have an excellent correlation with the FFR with adenosine in the assessment of intermediate coronary lesions.

In recent years, functional assessment after intervention has also been increasingly implemented, which, like intracoronary imaging, can make us change our attitude and correlate with the prognosis. The lower implementation of this practice, especially in multivessel patients, may result from having to lose the position of the wire to check equalization, difficulty in crossing the wire, wear/breakage of the material after diagnosis (2-3 vessels), use more time and contrast, etc. These problems could be reduced, at least partially, with the use of the workhorse coronary guidewire pressure microcatheter to measure post-PCI functional assessment. Although the usefulness of post-PCI FFR has been demonstrated, there is no clearly established cut-off value (0.84-0.96) and it seems that in reality the values are a continuum of risk so that the higher the value, the better the prognosis . Furthermore, other simpler indices such as rest or hyperemic indices without adenosine have not been correlated with FFR in post-PCI.

The purpose of this study is to evaluate the correlation between cFFR-NTG and other indices taking FFR as a reference in multivessel patients after undergoing intervention. Establish cut-off points and correlate it with adverse cardiovascular events (MACE) in a 1-year clinical follow-up.

Inclusion Criteria:

• Patients >18 years old and,
• Patients with multivessel coronary artery disease (multivessel coronary artery disease will be considered the presence of significant stenosis in 2 or more first or second order vessels greater than 1.5 mm in diameter with an angiographic reduction of their diameter ≥50% by visual estimation) subsidiary of percutaneous coronary revascularization in at least one of them and,
• Use of Navvus pressure microcatheter both for functional diagnosis and for post-PCI evaluation of the different vessels and,
• Patients who have signed the Informed Consent.

Exclusion Criteria:

• Patients with intolerance or contraindication to adenosine.
• Hemodynamically unstable patients, acute phase of a STEACS.
• Patient with significant comorbidity with limited life expectancy.
• Patients with the patient's express refusal to participate in the study.
• Pregnant or breastfeeding female patients.