Transit-time flowmetry (TTFM) allows grafts quality control during coronary artery bypass surgery by measuring the flow volume through them.

To date, many studies have deeply studied the predictive role on the graft outcomes of the various flowmetry-derived parameters. One of the least investigated aspects, however, is the mutual influence that two newly realized grafts can have. This possibility would be related to the presence of a more or less developed collateral circulation between the bypassed territories.

The purpose of this study is to assess whether a graft for a territory different than that provided by the left anterior descending artery (LAD) may affect the functionality (measured through flowmetry) of the left internal mammary artery - LAD graft.

Inclusion Criteria:

• age > 18 years;
• informed consent acquired and registered;
• patients who undergo coronary artery bypass grafting (with or without cardiopulmonary bypass);
• patients with stable angina, unstable angina or acute coronary syndrome without elevation of the ST tract (NSTEMI)

Exclusion Criteria:

• patients unable to give informed consent;
• patients undergoing emergency surgery;
• patients in unstable haemodynamic conditions or in need of pharmacological or mechanical support;
• patients undergoing combined surgery;
• patients undergoing single aortocoronary bypass surgery

All patients with coronary artery disease and an indication for surgical revascularization (coronary artery bypass grafting) who meet the above-described inclusion and exclusion criteria will be enrolled by signing the informed consent the day before surgery.

Patient data (personal data, anthropometric data, cardiovascular risk factors, co-patologies, cardiac history, blood tests, drug therapy, electrocardiogram, echocardiogram, angiography) will be recorded