Abstract 2541: Role of Stent Expansion on Hemodynamic Profile in Bifurcation Lesions
Backgrounds: Coronary artery bifurcation is governed by fractal geometry. Previous studies have shown that the ratio of parent vessel (PV) lumen diameter to the sum of the 2 daughter vessel lumen diameters is constant (fractal ratio=0.678; Finet’s law) in normal coronary arteries. The AXXESS stent is a novel self-expanding drug-eluting stent with flared configuration designed to be properly implanted and expanded at the level of carina. We sought to evaluate the hemodynamic compatibility of this self-expanding stent implanted in bifurcation lesion using volumetric intravascular ultrasound (IVUS) data.
Methods: From AXXESS stent trials, 31 patients who met all the following criteria were included in this study: non-left main bifurcation lesion, AXXESS stent in PV, conventional stents in both daughter vessels and available volumetric IVUS analysis of all 3 segments (PV and 2 daughter vessels). Average lumen diameter was obtained from the non-overlapped proximal 5-mm part of each vessel segment. Hemodynamic profile of bifurcation anatomy was evaluated by the diameter optimality which was defined as [measured-PV diameter]/[calculated ideal-PV diameter using the fractal ratio of 0.678].
Results: During mean follow-up duration of 8.7±2.1 months, average AXXESS stent area was increased by 28±17% and lumen area by 23±15%. Percent neointimal volume obstruction was 4.4±5.7%, 7.3±13.7% and 7.9±8.7% in PV and 2 daughter vessels, respectively. The expansion of AXXESS stent and lumen results in better hemodynamic profile (Lumen diameter optimality: 0.89±0.10 to 1.04±0.19, P<0.0001, Table⇓. When the law of energy conservation (Murray’s law) was applied, follow-up lumen diameter optimality was 1.10±0.16.
Conclusion: Expansion of AXXESS self-expanding stent during follow-up conforms to confer a hemodynamically more suitable bifurcation anatomy.