Aims: High rates of restenosis and stent thrombosis are still often observed after bifurcation stenting despite the recommended stent post-dilatation using the kissing balloon (KB) technique. We investigated the potential benefits of a final post-dilatation step in bifurcation stenting with a balloon that respects the natural diameter ratio of the proximal and distal vessels in bifurcations (Murray's law).
Methods and results: Fourteen commercially available stents (Xience V, Taxus Liberté and Presillion) were deployed in a silicone model of a coronary bifurcation using a provisional stenting approach. After side branch (SB) ostium dilatation and KB inflation, stent geometry and strut apposition was analysed using micro-CT. A final proximal inflation step was then performed to post-dilate only the proximal segment of the main vessel (MV). KB inflation produces an asymmetrical dilatation of the stent in the proximal part of the bifurcation with a number of struts left malapposed in the MV. Using the proposed final proximal inflation (FPI) step reduces the average stent eccentricity index from 0.72 to 0.90 (p<0.001) and the percentage of malapposed struts in the proximal part of the MV from 33.4% to 0.6% (p=0.02), while increasing the minimum stent area from 6.8 mm² to 8.5 mm² (p < 0.0001).
Conclusions: A final dilatation of the stent only in the MV proximal to the SB with a balloon sized according to the mother vessel is suggested to prevent stent malapposition and optimise stent deployment in bifurcation stenting.