BACKGROUND: Conformability has been shown to be a surrogate predictor of long-term outcomes and is dependent on stent material, strut thickness and design.
METHODS:
A total of 59 consecutive, contemporaneous patients were analyzed for conformability of which 30 patients were treated with the Supraflex stent and 29 patients with the Xience Prime stent. Patients with totally occluded arteries or excessive proximal tortuosity were excluded. Stents were assessed using a validated software analysis of arterial curvature and angulations at pre- and post- implantation. The absolute difference between post implantation and pre implantation was used as a surrogate of stent conformability.
Conformability was assessed by curvature and angulations of arterial curvature. Curvature is defined as the infinitesimal rate of change in the tangent vector at each point of the centreline.
RESULTS: In both the Supraflex and Xience Prime groups, there was a significantly lower curvature after treatment than before treatment. The relative changes in percentage (i.e., from pre-to post-treatment) in curvature was 22.31% in the Supraflex (from 0.502 to 0.390 cm-1, p < 0.001), whereas the corresponding reduction with the Xience Prime was 24.78% (from 0.557 to 0.419 cm-1, p < 0.001). The comparison between the two devices in terms of change in curvature showed a significant change (p = 0.016).
As with curvature analysis, angulation changed significantly after deployment. The relative changes in percentage of angulation within pre- and post-treatment measures resulted in less modification with the Supraflex, 10.80% (from 42.97° to 38.33°, p < 0.001), versus 27.04% with the Xience Prime (from 36.61° to 26.71°, p < 0.001). The comparison between the two devices in terms of change in angulation showed a non-significant trend in favor of Supraflex.
CONCLUSIONS: Both the stents cause alteration in vessel geometry measured in terms of curvature and angulation in coronary artery post-deployment. The conformability of Supraflex was better as compared to Xience Prime using curvature index but was marginally better using angulation index.
