Impact of Single-Vessel vs Multi-vessel CAD on Long-Term Mortality in Patients with Diabetes Mellitus Undergoing PCI

Background: Long-term outcomes of percutaneous coronary intervention (PCI) for multi-vessel disease (MVD) with diabetes mellitus (DM) are inferior to coronary artery bypass grafting (CABG), but the outcomes of PCI in diabetics with single vessel disease (SVD) are less well known. We aimed to assess the long-term mortality of patients with DM with SVD compared to MVD undergoing PCI. Methods: We included 8,795 consecutive patients with DM undergoing PCI from 34,784 patients in the Melbourne Interventional Group registry (2005–2018). Patients were stratified based on whether they had SVD or MVD. Long-term mortality was assessed via linkage with the National Death Index (NDI). Results: 6,138 (70%) of DM patients had MVD. Compared to SVD, MVD were older (67 ± 11 vs 64 ± 10 years), with higher rates of hypertension, insulin dependence, prior PCI, renal impairment, left ventricular ejection fraction <45%, cardiogenic shock and out-of-hospital cardiac arrest (all p < 0.001). Patients with MVD had significantly higher rates of stent thrombosis, unplanned CABG and major bleeding with lower procedural success and 30-day major adverse cardiac events (5.5% vs 2.6%, p < 0.001). Long-term mortality (mean 5.4 ± 3 years) was significantly higher in MVD (28% vs 17%, p < 0.001). Cox proportional hazard modelling found MVD as an independent predictor of long-term mortality (HR 1.37, 95% CI 1.2–1.5, p < 0.001). Conclusion: Patients with DM and SVD undergoing PCI had a lower long-term mortality compared to MVD. However, the mortality beyond 3 years in SVD increases, mandating aggressive risk factor control and close clinical follow-up.