P1434 Evolution of coronary wall shear stress following implantation of bioabsorbable vascular scaffolds - first results of a 1-year follow-up pilot study

Funding Acknowledgements

This research has been funded by the research grant PlaqueImage, contract number 26/01.09.2016, SMIS code 103544, Project funded by the European Union

Aims

Coronary shear stress (CSS) has been recently recognized to play a significant role in coronary plaque progression and vulnerabilisation. However, the evolution of CSS after implantation of different types of coronary stents is still under investigation. The aim of this study was to assess the evolution of the CSS along the coronary lesions following implantation of bioabsorbable vascular scaffolds (BVS), to determine the impact of BVS on coronary flow haemodynamics.

Methods and results

This was a single center prospective pilot study which enrolled 15 patients (aged 58.35 +/- 7.79 years, 13 males) with coronary artery disease undergoing BVS implantation in a major epicardial vessel. In all patients, angio CT scanning (Siemens Somatom Sensation scanner, Erlangen, Germany) was performed prior to the BVS implantation and repeated after 12 months. Lumen information was extracted from the vessels of interest and coronary rest hemodynamics, including CSS, were calculated using a computational fluid dynamics solver. All shear stress calculations were performed at baseline and repeated after 1 year. Average CSS was determined proximally, distally, and at the level of the minimal lumen area (MLA). Average CSS along the stented segment significantly decreased after BVS implantation, from 2.87 +/- 1.64 Pa at baseline to 1.9 +/- 0.49 at 1 year (p = 0.0001). Maximum CSS along the segment also exhibited a significant decrease, from 11.78 +/- 10.06 Pa to 6.35 +/- 3.08 Pa (p = 0.0009). Proximally to the MLA, CSS significantly decreased after BVS implantation, from 3.39 +/- 1.93 Pa at baseline to 1.91 +/- 0.68 Pa at 1 year (p <0.0001). However, this decrease in CSS was not significant distally to the MLA (1.3 +/- 0.72 Pa vs 1.59 +/- 0.65 Pa, p = 0.9).

Conclusions

Implantation of BVS leads to a significant decrease of CSS after 1 year, especially within coronary segments located proximally to the stenosis. This underlines the role of BVS in re-establishing a physiological pattern of coronary flow in diseased coronary vessels. The feature (mentioned herein) is not commercially available. Due to regulatory reasons its future availability cannot be guaranteed.

P1823 Feasibility of CCTA in assessment of luminal changes and coronary shear stress evolution after implantation of bioresorbable vascular scaffolds

Funding Acknowledgements

PlaqueImage - financed by the National Authority of Scientific Research and Innovation and the Romanian Ministry of European Funding

Background

Coronary shear stress (CSS) is a well-established local mechanical factor in atherogenesis, progression and destabilization of atherosclerotic plaques. Analysis of CSS after coronary stent placement is still lacking of large clinical studies. Purpose: The aim of this study was to: (1) test the feasibility of Coronary Computed Tomography Angiography (CCTA) for assessment of local hemodynamic and luminal changes after implantation of bioresorbable vascular scaffolds (BVS), and (2) to investigate CSS modifications after BVS implantation. Methods: We conducted a single center, prospective pilot study on 73 patients with coronary artery disease who underwent elective percutaneous coronary intervention (PCI); group 1 (n = 30) – patients with BVS and group 2 (n = 43) – patients with bare metal stent (BMS) implanted. CCTA scanning was performed in all patients prior PCI and at 12 months after PCI. The mean CSS at proximal and at distal part of the stented segment and at the level of the minimal lumen area (MLA) was calculated at baseline and at 12 months after BVS placement. Results: CCTA revealed a higher incidence of severe coronary stenosis in group 1 (73%) than in group 2 (30%) (p < 0.0001). Sensibility of visual evaluation for identification of in-stent restenosis on CCTA was increased in BVS group (94%) than in BMS group (76.19%) (p = 0.0006), hence the group 1 had lower incidence of non-diagnostic evaluations. Mean CSS at the stented site was significantly lower at 12 months (1.9 +/- 0.68 Pa) that average CSS at baseline (2.87 +/- 3.08 Pa) (p = 0.0001). CSS analysis showed also a significantly decreased values at proximal level from 3.39 +/- 1.93 Pa at baseline to 1.91 +/- 0.68 Pa at follow up (p < 0.0001), but not a significant decrease at distal part – 1.3+/-0.72 Pa at baseline and 1.59 +/- 0.65 Pa at 12 months follow up (p = 0.9). Conclusions: CCTA is a feasible technique for assessment of luminal changes following BVS implantation. BVS implantation contribute to the improvement of local hemodynamics by restoring physiological pattern of coronary flow, as demonstrated by the computational fluid hemodynamics assessment of coronary circulation.