Intra-individual changes of active matrix metalloproteinase-9 are associated with clinical in-stent restenosis of bare metal stents

Abstract

Objectives: Increased chronic postprocedural levels of active matrix metalloproteinase-9 (MMP-9) have been associated retrospectively with a history of in-stent restenosis (ISR). This study aimed to determine whether index or post-percutaneous coronary intervention (PCI) plasma levels of active MMP-9 are a predictor of subsequent clinical ISR, in a standard population of patients treated with bare metal coronary stents.

Methods: Four hundred thirty-two patients were prospectively recruited and sampled at index and 3 and 6 months after PCI. Those who developed symptomatic angiographically confirmed ISR were compared to randomly selected, asymptomatic controls, stratified by index presentation in a nested case-control design. Plasma samples were analyzed for the active form of MMP-9.

Results: In all, 35 patients (8.1%) developed ISR, and these were compared to 98 controls. The increase in active MMP-9 over 3 months was significantly greater in the ISR group (p = 0.030) and independent of the established risk factors. Index clinical presentation was not associated with acute changes in active MMP-9; however, patients with ST-elevation myocardial infarction had greater increases in active MMP-9 at 3 months.

Conclusions: The change in active MMP-9 over 3 months after bare metal coronary stent placement appears to be independently associated with the development of ISR in a standard PCI population.