Coronary artery overexpansion increases neointimal hyperplasia after stent placement in a porcine model.
OBJECTIVE
To determine if an aggressive approach to coronary revascularisation with oversized balloons is counterproductive, we studied the effect of increasing balloon-to-artery (B:A) ratio on neointimal hyperplasia following primary stent placement using a non-atherosclerotic porcine coronary overstretch model.


METHODS
60 vessels in 33 Yorkshire swine were randomly assigned to one of five B:A ratios between 1.0:1 and 1.4:1. Intravascular ultrasound (IVUS) imaging was performed before bare-metal stent placement to accurately determine vessel size, after stent placement, and at 28 days.


RESULTS
The mean prestent vessel diameter was 3.05 (0.31) (SD) mm. In-stent neointimal volume, in-stent volume stenosis and cross-sectional area stenosis at the stent minimum lumen diameter increased significantly with increasing achieved B:A ratio (multilevel regression test for slope, p<0.001, p = 0.002 and p<0.001, respectively) and were independent of vessel size. Even minor vessel overstretch at an achieved B:A ratio of 1.1:1 resulted in significant neointimal hyperplasia. Larger B:A ratios were also associated with more neointima beyond the stent edges (p = 0.008). For vessels from the same animal, neointimal response at a given B:A ratio was dependent upon the animal treated.


CONCLUSIONS
In a porcine model of IVUS-guided coronary primary stent placement, vessel overexpansion is counterproductive. Neointimal hyperplasia at 28 days is strongly associated with increasing B:A ratio. In addition, vessels do not respond independently of each other when multiple stents are placed within the same animal using a range of B:A ratios.
Russo
Robert J
RJ
Division of Cardiovascular Diseases, Scripps Clinic, SW206, 10666 North Torrey Pines Road, La Jolla, CA 92037, USA. Russo.Robert@ScrippsHealth.org
Silva
Patricia D
PD
Yeager
Mark
M
D000818:Animals; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods*; D003331:Coronary Vessels / Q000473:pathology / Q000601:surgery*; D006965:Hyperplasia / Q000473:pathology; D011897:Random Allocation; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000473:pathology*; D018084:Ultrasonography, Interventional