Influence Of Overexpansion On In-stent Restenosis In Drug Eluting Stent

Background—Overexpansion in drug eluting stent is common in clinical practice.Basic researches have revealed that overexpansion is associated with in-stentrestenosis, while rarely clinical study evidence exists. This study was designed toassess the effects of stent overexpansion on in-stent restenosis in the real world.Method—This was a single-center, retrospective cohort study. A total of124patientswith162lesions were enrolled, who were been implanted drug eluting stentsuccessfully in the year of2012and received coronary angiography in9-12follow-upvisit. According to the ratio between stent diameter and reference artery diameter afterstent implanted (S:A),76lesions (46.91%) were overexpanded while86were not.Result—For indexes of intimal hyperplasia, overexpansion group were higher thanthat in non-overexpansion group, the differences became more obvious afterpropensity score matching: diameter stenosis percentage (DSP) at follow-up in stentwere22.15±24.50%vs11.62±15.17%(p=0.007); DSP in segment were27.29±23.25%vs12.77±15.92%(p <0.001); late lumen loss (LLL) were0.52±0.65mm vs0.21±0.55mm (p=0.007). The subgroup analysis of distal segmentshowed precise expansion (S:A=0.95-1.05) induced lower intimal hyperplasia thanunderexpansion (0.8-0.95), slight overexpansion (1.05-1.20) and gross overexpansion(>1.20): DSP at follow-up were5.93±11.99%vs10.37±10.02%,14.23±18.25%and25.25±15.23%(p=0.003); LLL were0.14±0.42mm vs0.87±1.72mm,0.45±0.66mmand0.67±0.51mm (p<0.001). Multiple linear regression was performed, DSP atfollow-up in distal segment has a positive relationship with expansion extent (r=0.27,p=0.001).Conclusion—Stent overexpansion could induce intimal hyperplasia and had adose-effect relationship with the extent of in-stent restenosis. Overexpansion in the distal point of stent would make the edge restenosis.