Elevated levels of plasma inactive stromal cell derived factor-1a predict long-term adverse outcomes in diabetic patients with coronary artery disease

Abstract Background Because of the significantly increased cardiovascular risk by complicating type 2 diabetes (T2D) in patients with coronary artery disease (CAD), the appropriate risk estimation is crucial in patients with T2D following percutaneous coronary intervention (PCI). Nevertheless, there is no established biomarker which can precisely predict outcomes in this particular population. Although stromal cell derived factor-1α (SDF-1α) has been suggested to play a key role in the pathogenesis of T2D, the prognostic impact of SDF-1α in the secondary prevention of CAD is yet to be elucidated. In particular, the ability of SDF-1α isoforms in outcome prediction in this population has not been assessed. Purpose The aim of present study was to investigate the prognostic implication of three isoforms of SDF-1α, such as total, active, and inactive forms of SDF-1α in diabetic patients following PCI. Methods This single-center retrospective analysis involved consecutive patients with T2D who underwent PCI for the first time between 2008 and 2018 (n=849). Primary and secondary outcome measures were all-cause death and the composite of cardiovascular death, non-fatal myocardial infarction, and ischemic stroke (3P-MACE), respectively. For determining plasma levels of SDF-1α, we measured not only total, but also the active type of SDF-1α by ELISA. Inactive isoform of the SDF-1α was calculated by subtracting the active isoform from total SDF-1α. Participants were divided into two groups according to the median of three forms of plasma SDF-1α levels (total SDF-1α: 2270 pg/mL, active SDF-1α: 686 pg/mL, inactive SDF-1α: 1537 pg/mL) at PCI procedure and the incidence and risk of subsequent endpoints following PCI were assessed. Results Kaplan-Meier analyses revealed increased risk of both all-cause death and 3P-MACE in patients with elevated levels of inactive SDF-1α (Figure 1). Constantly, multivariate Cox hazard analyses adjusted by age, sex, body mass index (>25), acute coronary syndrome, and chronic kidney disease (≥ stage 3) repeatedly indicated the 1 higher log-transformed inactive SDF-1α was significantly associated with increased risk of all-cause death (hazard ratio (HR): 2.21, 95% confidence interval (CI): 1.05–4.67, p=0.04) and 3P-MACE (HR: 2.30, 95% CI: 1.01–5.09, p=0.04). However, neither of total and active SDF-1α reached statistical significance (Figure 2). Furthermore, the addition of inactive SDF-1α to baseline models in multivariate Cox proportional hazard analysis significantly enhanced both the net reclassification improvement (NRI) and the integrated discrimination improvement (IDI) for all-cause death (NRI 0.29, p=0.009; IDI 0.007, p=0.03) and 3P-MACE (NRI 0.38, p=0.001; IDI 0.007, p=0.01) while adding total and active SDF-1α did not improve them. Conclusion In diabetic patients following PCI, elevated levels of plasma inactive SDF-1α, not total and active isoforms, might be a useful indicator of adverse outcomes.