Background: The efficacy of percutaneous coronary intervention (PCI) is limited by the need for repeat revascularization resulting from restenosis. The restenosis rate after treatment for in-stent restenosis (recurrent restenosis) is high (> 30%). Numerous studies have suggested the predictive value of interleukin 6 (IL-6) and transforming growth factor beta1 (TGF-beta1).
Methods: We sought to determine whether serum levels of IL-6 and TGF-beta1 could help identify individuals with recurrent restenosis. Thirty seven patients with a history of stent implantation were enrolled and divided into three groups: (1) patients with a current, first restenosis (n = 9); (2) patients with current restenosis and at least one prior restenosis (recurrent restenosis) (n = 11), and (3) patients with a history of restenosis, but without current restenosis (n = 17).
Results: The baseline profile was similar in all three groups. The median (25th-75th percentile) concentrations of IL-6 were: group 1 - 2.8 (1.4-5.5); group 2 - 2.6 (0.6-8.6); group 3 - 2.4 (0.9-4.7) p = 0.69 and TGF-beta1: group 1 - 3.6 (0.2-14.4); group 2 - 4.2 (1.8-57.6); group 3 - 6.6 (2.8-30.0) p = 0.57. Moreover we found no correlation, either between diameter stenosis and IL-6 (R = 0.10; p = 0.38) or TGF-beta1 (R = 0.10; p = 0.57). Both IL-6 (AUC 0.59 p = 0.4 and AUC 0.51 p = 0.9) and TGF-beta1 (AUC 0.64 p = 0.2 and AUC 0.50 p = 0.9) failed to provide significant results in receiver-operating characteristic analysis.
Conclusion: We report that there is no association between the severity of diameter stenosis (restenosis) and IL-6 or TGF-beta1 concentrations. Our findings might suggest that levels of IL-6 and TGF-beta1 have no predictive value for identifying patients with recurrent restenosis.