Pressure rinsing of coronary stents immediately before implantation reduces inflammation and neointimal hyperplasia

OBJECTIVES This study evaluates whether rinsing stems with high pressure im mediately before implantation minimizes stunt-induced inflammation and neoi ntimal formation. BACKGROUND Several reports indicate that manual stent manipulation before i mplantation results in foreign body contamination and increased neointimal hyperplasia. METHODS A stent-cleaning chamber was developed to rinse stems at a sustaine d hydrodynamic pressure of 4 atm for 10 s. Commercial pre-mounted stems wer e examined with different levels of manipulation: 1) untouched stems: no st ent manipulation before implantation; 2) handled stems: manual stent re-cri mping on the balloon; 3) rinsed stems: pressure-rinsed with the stent-clean ing chamber. In vitro surface analysis was evaluated by scanning electron m icroscopy. Neointimal hyperplasia and inflammation around stent struts were also assessed in the pig in-scent restenosis model. RESULTS In vitro analysis revealed fewer contaminants on rinsed stems compa red with untouched (p = 0.01) and handled stems (p < 0.001). In vivo, neoin timal thickness, neointimal area and vessel percent stenosis were significa ntly reduced in rinsed, compared with nut-rinsed, stems (p = 0.002, p = 0.0 07, p = 0.008 respectively). In addition, a significant reduction in the in flammatory infiltrate around struts was observed in untouched, compared wit h handled, stems (p = 0.04) and in rinsed, compared with not-rinsed, stents (p < 0.001). Regression analysis accounting for injury and neointimal thic kness showed significant differences in slopes between "handled + not-rinse d" and "handled + rinsed" stems (p = 0.004), and between "untouched + not-r insed" and "untouched + rinsed scents" (p = 0.037). CONCLUSIONS Rinsing scents under high pressure immediately before coronary implantation results in less inflammation around struts and thinner neointi ma at 28 days in this pig model. (J Am Coll Cardiol 2001;38:562-8) (C) 2001 by the American College of Cardiology.