Patients with coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM) often present with diffuse, complex lesions and a higher risk of in-stent restenosis after PCI. While drug-eluting stents (DES) remain the standard treatment, their long-term efficacy in diabetic patients is suboptimal. Drug-coated balloons (DCBs) offer a "leave nothing behind" strategy by delivering anti-proliferative drugs without permanent implants, potentially reducing restenosis and adverse events. Although DCBs have shown promise in selected lesion types, evidence in T2DM patients is limited, particularly from prospective, randomized trials. This study aims to evaluate the efficacy and safety of DCB angioplasty compared to conventional strategies in patients with CAD and T2DM, focusing on angiographic outcomes, symptom relief, and major adverse cardiovascular events.

Coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM) often coexist, and the long-term hyperglycemic state and metabolic disorders in diabetic patients contribute to endothelial dysfunction and accelerated atherosclerosis. As a result, coronary lesions in T2DM patients tend to be more diffuse and complex, posing greater challenges to percutaneous coronary intervention (PCI). Although drug-eluting stents (DES) have significantly improved clinical outcomes, diabetic patients remain at higher risk for in-stent restenosis (ISR) and target lesion revascularization (TLR), negatively impacting long-term prognosis.

Drug-coated balloons (DCBs), a novel PCI technique, allow for rapid and effective delivery of anti-proliferative agents (e.g. paclitaxel or sirolimus) to the vessel wall without leaving behind a permanent implant. This "leave nothing behind" approach reduces the risk of chronic inflammation and stent-related complications. DCBs have shown promising results in non-diabetic populations, particularly in small vessel disease and bifurcation lesions. However, evidence supporting their use in T2DM patients remains limited, especially from prospective, randomized controlled trials. As such, whether DCBs can serve as a viable alternative to DES in this high-risk group remains an open question.

This study aims to evaluate the efficacy and safety of DCB angioplasty in patients with CAD and T2DM through a prospective, randomized controlled design. The study will focus on restenosis rates, improvement in angina symptoms, incidence of major adverse cardiovascular events (MACE), and patient-reported quality of life outcomes, providing a more individualized and evidence-based treatment approach for this challenging patient population.

Inclusion Criteria:

• Age ≥18 years
• Diagnosed CAD with ≥70% stenosis in ≥1 coronary artery confirmed by coronary angiography
• Diagnosed type 2 diabetes (per WHO criteria)
• Target lesion suitable for DCB (diameter 2.0-4.0 mm, length ≤40 mm)
• Informed consent provided

Exclusion Criteria:

• Prior coronary artery bypass surgery or PCI with complications
• STEMI within 24 hours
• Severe hepatic/renal dysfunction
• Active bleeding or uncontrolled anticoagulation
• Allergy to DCB components
• Pregnancy or lactation
• Psychiatric conditions limiting compliance