Background The acute inflammatory response of high-pressure post-dilation with non-compliant balloon (HPNC)after drug-eluting stent (DES) deploymentremains still unknown.We sought to evaluate the inflammatory effects and clinical outcomes of HPNCafter DES implantation.Methods We enrolled consecutive patients with stable angina pectoris, who were treated with single drug-eluting stentdeployed by nominal pressure in de novo ischemia-related coronary artery.In this per-protocol study, patients were divided into HPNC group (≥14atm) or non-HPNC group.The development of inflammatory markers (C-reactive protein and interleukin-6) was used to evaluate the acute inflammatory response of HPNC (baseline, 1, 6, 24 and 72 hours after procedure).The baseline reference vessel diameter, minimal stent diameter soon after DES deployment, and final minimal stent diameter after HPNC were measured by quantitative coronary analysis.All patients were followed up for 1 year.Results There was no significant difference between the-HPNC group (n=42) and non-NPNC group (n=11) with regard to the changes of inflammatory markers (CRP, P=0.739; IL-6, P=0.936) within 72 hours after procedure.The minimal stent diameter after HPNC was larger compared with soon after stent deployment (2.71±0.43mm vs 2.47±-0.41mm, P<0.001).The percentage to reference vessel diameter after HPNC was also larger compared with soon after stent deployment (85.5±12.1% vs 77.9±11.8%, P<0.001).There was no adverse coronary event in the two groups at 1 year.Conclusions The acute systemic inflammatory response induced by HPNC appeared to be similar to that induced only by stent deployment.HPNC achieved larger stent diameter, which was associated with similar in-hospital and long-term outcomes compared with stent deployment only.