The RITMO (Registro Italiano sul trattamento del Tronco coMune non protettO) observational study will appraise the prevalence, management strategy, and prognosis of unprotected left main coronary artery disease in Italy.

The RITMO (Registro Italiano sul trattamento del Tronco coMune non protettO) observational study will be a prospective, multicenter, observational study aiming to appraise the prevalence, management strategy, and prognosis (up to 5 years) of unprotected left main coronary artery disease in Italy. A total of 45 Italian secondary and tertiary care centers will participate, and enroll patients during a period of 12 to 18 months. Patients will be included provided that they complete a written informed consent form and significant unprotected left main coronary artery disease is established at diagnostic coronary angiography. The primary end-point will be the 12-month rate of major adverse cerebro-cardiovascular events (ie death, myocardial infarction, stroke, or coronary revascularization).

Inclusion Criteria:

• angiographic evidence of significant unprotected left main disease
• lack of patent bypass grafts for the left coronary system
• willingness to complete written informed consent form
• willingness to comply with subsequent follow-up contacts

Exclusion Criteria:

• lack of written informed consent form
• inability to comply with subsequent follow-up contacts

Patients with suspected coronary artery disease undergoing diagnostic coronary angiography.