Pressure rinsing of coronary stents immediately before implantation reduces inflammation and neointimal hyperplasia.
OBJECTIVE
This study evaluates whether rinsing stents with high pressure immediately before implantation minimizes stent-induced inflammation and neointimal formation.


BACKGROUND
Several reports indicate that manual stent manipulation before implantation results in foreign body contamination and increased neointimal hyperplasia.


METHODS
A stent-cleaning chamber was developed to rinse stents at a sustained hydrodynamic pressure of 4 atm for 10 s. Commercial pre-mounted stents were examined with different levels of manipulation: 1) untouched stents: no stent manipulation before implantation; 2) handled stents: manual stent re-crimping on the balloon; 3) rinsed stents: pressure-rinsed with the stent-cleaning chamber. In vitro surface analysis was evaluated by scanning electron microscopy. Neointimal hyperplasia and inflammation around stent struts were also assessed in the pig in-stent restenosis model.


RESULTS
In vitro analysis revealed fewer contaminants on rinsed stents compared with untouched (p = 0.01) and handled stents (p < 0.001). In vivo, neointimal thickness, neointimal area and vessel percent stenosis were significantly reduced in rinsed, compared with not-rinsed, stents (p = 0.002, p = 0.007, p = 0.008 respectively). In addition, a significant reduction in the inflammatory infiltrate around struts was observed in untouched, compared with handled, stents (p = 0.04) and in rinsed, compared with not-rinsed, stents (p < 0.001). Regression analysis accounting for injury and neointimal thickness showed significant differences in slopes between "handled + not-rinsed" and "handled + rinsed" stents (p = 0.004), and between "untouched + not-rinsed" and "untouched + rinsed stents" (p = 0.037).


CONCLUSIONS
Rinsing stents under high pressure immediately before coronary implantation results in less inflammation around struts and thinner neointima at 28 days in this pig model.
Bayes-Genis
A
A
Division of Cardiovascular Diseases, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
Camrud
A R
AR
Jorgenson
M
M
Donovan
J
J
Shogren
K L
KL
Holmes
D R
DR
Schwartz
R S
RS
D000818:Animals; D003327:Coronary Disease / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D005549:Foreign-Body Reaction / Q000473:pathology / Q000517:prevention & control; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D007249:Inflammation / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D008854:Microscopy, Electron; D011312:Pressure; D055672:Static Electricity; D015607:Stents / Q000009:adverse effects*; D013552:Swine