Comparison of safety and long-term outcomes of retrograde chronic total occlusion percutaneous coronary intervention in patients with vs. without diabetes mellitus: a retrospective cohort study.

BACKGROUND: The safety profile and long-term outcomes of retrograde percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) in patients with diabetes mellitus (DM) remain inadequately characterized. We evaluated procedural and extended follow-up results in this cohort. METHODS: This single-center retrospective study enrolled adults undergoing retrograde CTO-PCI; individuals with incomplete data, malignancy, or end-stage renal disease were excluded. Primary and secondary outcomes were all-cause mortality and major adverse cardiovascular events (MACE), respectively. Intergroup comparisons used standard univariate tests. Cumulative hazard functions were estimated via the Nelson-Aalen method, and multivariable Cox proportional hazards models were performed to adjust for clinical confounders and identify variables associated with MACE. RESULTS: In total, 836 patients met the criteria. Success rates for collateral channel (CC) tracking (92.0% in the DM group vs. 95.0% in the non-DM group, P=0.08), retrograde PCI success (87.4% in the DM group vs. 91.3% in the non-DM group, P=0.07), and final recanalization (89.4% in the DM group vs. 92.0% in the non-DM group, P=0.20) were statistically similar. In-hospital complication rates were minimal and comparable (all P>0.05). Follow-up data were obtained for 767 patients (91.7%) over a median of 1,041 days. Patients with DM experienced a significantly higher risk of MACE (19.2% in the DM group vs. 13.9% in the non-DM group, P=0.046), primarily driven by increased all-cause mortality (9.3% in the DM group vs. 4.5% in the non-DM group, P=0.007) and cardiac death (7.4% in the DM group vs. 2.2% in the non-DM group, P<0.001). After multivariable adjustment for clinical confounders, DM remained a strong independent predictor of higher long-term all-cause and cardiac mortality. CONCLUSIONS: Retrograde PCI is technically safe and effective in CTO patients with DM. However, this cohort carries a significantly higher long-term risk of mortality and MACE than non-diabetic counterparts, necessitating intensified post-procedural risk-factor management.