Coronary artery disease is a leading cause of mortality and morbidity globally. The left coronary artery system is critically important due to its supply of a large area of myocardium. Ostia lesions of left anterior descending artery [LAD] and circumflex artery [CX]) present technical challenges during percutaneous coronary intervention (PCI) and are considered high-risk lesions due to their anatomical location, relationship with the left main coronary artery bifurcation. Two main approaches exist for treating these lesions: accurate ostial stenting and crossover stenting extending from the left main coronary artery to the relevant branch. Accurate ostial stenting aims to avoid unnecessary stenting of the left main coronary artery, while crossover stenting is more advantageous in terms of ensuring complete coverage of the ostial region. However, the crossover approach may have disadvantages such as larger stent implantation and potential side branch involvement. The current literature does not clearly define the clinical superiority of these two strategies. While various studies have shown no significant difference in mortality, myocardial infarction, and target lesion revascularization, the results are heterogeneous, and a definitive consensus has not been reached. The majority of current data are based on retrospective or observational studies. Therefore, well-designed prospective studies comparing crossover stenting and accurate ostial stenting strategies in the ostial left-sided coronary artery (LAD and CX) lesions are needed. This planned study aims to contribute to this gap in the literature by comparing the clinical outcomes of the two approaches.

There are significant conceptual differences between accurate ostial stenting and crossover stenting strategies extending from the left main coronary artery to the target vessel. The isolated approach aims to avoid unnecessary left main coronary artery stenting, while the crossover technique aims to minimize the risk of residual stenosis by ensuring complete coverage of the ostial segment. However, the current literature presents inconsistent and heterogeneous results regarding the clinical superiority of these two approaches. The current evidence is based on retrospective analyses and observational records, and the lack of prospective and methodologically robust comparative studies is noteworthy. In this context, a prospective evaluation of these two strategies is critical not only for comparing clinical outcomes but also for standardizing the interventional approach. In particular, a systematic comparison based on clinically significant endpoints such as major adverse cardiovascular events (MACE), target lesion revascularization, and procedural success has the potential to fill the existing knowledge gap. This planned study aims to generate high-level evidence regarding which stenting strategy is superior in the treatment of left coronary artery ostial lesions. The findings are expected to make clinical decision-making processes more rational and evidence-based, and to improve patient prognosis. In this respect, the study has high potential for impact both in clinical practice and in the scientific literature.

This study aims to generate high-level evidence regarding which stenting strategy is superior in the treatment of ostial lesions of the left-sided coronary artery. It compares the 1-year clinical outcomes of patients treated with accurate ostial stenting and those treated with crossover stenting extending from the left main coronary artery to the target vessel.

The study was designed as a multicenter and prospective study between May 2026 and May 2027. Patients meeting the inclusion criteria who had critical ostial lesions of the left anterior descending artery and circumflex artery and underwent revascularization with accurate ostial stenting and crossover stenting extending from the left main coronary artery to the target vessel will be included. Patients will attend follow-up visits at 1 month, 6 months, and 12 months. At each visit, routine examinations will include biochemical parameters, ECG, and, if clinically necessary, ischemia investigation (exercise stress test, myocardial perfusion scintigraphy, coronary CT angiography) in the presence of ischemic symptoms. Control angiography will be performed if clinically necessary (>10% ischemia in scintigraphy, unstable angina pectoris, acute coronary syndrome). The following parameters will be recorded in detail in the study dataset for patients: age, gender, height, weight, Body Mass Index, smoking, diabetes mellitus, chronic renal failure, hypertension, hyperlipidemia, peripheral arterial disease, chronic obstructive pulmonary disease, left ventricular ejection fraction, symptoms, previous coronary intervention, multivessel disease, severe valvular disease, medical treatment parameters, procedural and angiographic parameters, 12-month mortality, myocardial Infarction, ee-intervention, stent thrombosis, and stroke.

Inclusion Criteria:

• Ostial left anterior descending artery or left circumflex artery disease
• Coronary intervention with second or third generation drug-eluting stent

Exclusion Criteria:

• Severe left main disease (≥30%, intravascular ultrasound plaque burden >50%)
• History of coronary bypass grafting
• Cardiogenic shock
• Left main diameter greater than stent expansion capacity (for crossover group)
• In-stent restenosis
• End-stage liver or kidney disease (cirrhosis, hemodialysis-dependent chronic kidney disease),
• Coronary intervention with bare-metal stent
• Early discontinuation or inappropriate use of DAPT treatment
• Patients lost to follow-up
• Patient life expectancy <1 year (such as cancer)

Medina 0.0.1 and 0.1.0 left main bifurcation disease