The aim of this study is to compare coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in the treatment of isolated chronic total occlusion (CTO) of the left anterior descending (LAD) artery in terms of short- and mid-term clinical outcomes, myocardial revascularization success, and complication rates.

Chronic total occlusion (CTO) represents one of the most challenging subgroups of coronary artery disease and is closely associated with adverse cardiovascular outcomes. Previous studies have demonstrated that patients with CTO experience a higher incidence of major adverse cardiovascular events compared with patients without CTO but with significant coronary artery disease (CAD), even after adjustment for demographic characteristics, clinical parameters, and disease severity. Among these patients, those with unrevascularized CTO constitute the highest-risk group, whereas successful revascularization has been shown to reduce the risk to a level comparable to that of patients without CTO but with significant CAD.

Among CTOs, isolated total occlusion of the left anterior descending (LAD) artery has particular clinical importance due to its critical role in myocardial perfusion. Two main revascularization strategies are currently used in the treatment of isolated LAD CTO: percutaneous coronary intervention (PCI) and single-vessel coronary artery bypass grafting (CABG). In surgical revascularization, the left internal mammary artery (LIMA) is most commonly used, although saphenous vein grafts may be preferred in selected cases.

However, direct comparative data between these two treatment strategies in this specific patient population remain extremely limited. In particular, differences between CTO-PCI and single-vessel CABG with respect to revascularization success, in-hospital events, and early post-discharge outcomes have not been systematically evaluated. In the present study, within the framework of the RITUAL study, the outcomes of CTO-PCI and CABG surgery were compared in patients with isolated LAD CTO.

Inclusion Criteria:

• Age 18 years or older at the time of the index procedure.
• Diagnosis of isolated chronic total occlusion (CTO) of the left anterior descending (LAD) coronary artery.
• Isolated LAD CTO defined as a de novo or in-stent total occlusion confined to the LAD artery, without significant coronary artery disease (defined as ≥50% stenosis) in other major epicardial coronary arteries, including the left circumflex (LCx), right coronary artery (RCA), or major side branches.
• No prior percutaneous coronary intervention (PCI) performed in non-LAD coronary arteries.
• Patients who underwent coronary revascularization with either coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) for isolated LAD CTO.

Exclusion Criteria:

• History of malignancy or active malignant disease at the time of the index procedure.
• Prior coronary artery bypass grafting (CABG) or prior percutaneous coronary intervention (PCI) performed in non-LAD coronary arteries.
• Presentation with ST-segment elevation myocardial infarction (STEMI).
• Discontinuation of prescribed medical therapy by patient preference within one year after the index procedure.
• Presence of multiple chronic total occlusions (CTOs) involving more than one coronary artery.
• Significant side branch disease of the LAD requiring two bypass grafts.
• Performance of crossover stenting from the LAD into the left main coronary artery during LAD CTO-PCI.
• Treatment of LAD CTO with drug-eluting balloon (DEB) angioplasty without stent implantation.
• Left ventricular ejection fraction (LVEF) less than 30%.
• Presence of severe valvular heart disease (e.g., severe aortic or mitral stenosis or regurgitation).
• Incomplete angiographic or clinical follow-up data.
• Use of mechanical circulatory support devices due to advanced heart failure, including intra-aortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), or left ventricular assist device (LVAD).

The study population consists of adult patients aged 18 years or older with isolated chronic total occlusion (CTO) of the left anterior descending (LAD) coronary artery who underwent coronary revascularization with either coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) as part of routine clinical care. Isolated LAD CTO was defined as a de novo or in-stent total occlusion confined to the LAD artery, without significant coronary artery disease (≥50% stenosis) in other major epicardial coronary arteries. Patients with prior coronary revascularization, multiple CTOs, severe left ventricular dysfunction, or incomplete follow-up data were excluded.

Individual participant data will not be shared due to the retrospective design of the study and institutional data privacy policies.