The Official Journal of EuroPCR and the European Association of Percutaneous Coronary Interventions (EAPCI)

Bench test and in-vivo evaluation of longitudinal stent deformation during proximal optimisation

DOI: 10.4244/EIJ-D-21-00824

1. University Heart Center Graz, Department of Cardiology, Medical University of Graz, Graz, Austria; 2. Second Department of Internal Medicine, Division of Invasive Cardiology, University of Szeged, Szeged, Hungary; 3. The Lambe Institute for Translational Medicine, Smart Sensors Lab and Curam, Saolta University Healthcare Group, Galway, Ireland; 4. Bristol Heart Institute, University of Bristol, Bristol, United Kingdom; 5. Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom

Background: While radial stent deformation has been thoroughly investigated, data on longitudinal deformation are scarce.

Aims: The aim of the study was to describe longitudinal stent deformation associated with the proximal optimisation technique (POT).

Methods: Longitudinal stent deformation was assessed by bench testing and by clinical evaluation. Bench testing was performed in silicone models using 3.00 (n=15) and 3.50 mm (n=14) stent platforms. After deployment, stents were sequentially post-dilated in the proximal main branch up to 5.50 mm, in increments of 0.50 mm, in order to simulate a spectrum of overexpansion. Stent length was redefined by optical coherence tomography (OCT) after each step. Clinical data were collected retrospectively from OCT-guided bifurcation PCI cases.

Results: In bench tests, POT has led to significant stent elongation in all cases. The magnitude of elongation was comparable between the 3.00 and the 3.50 mm stent platforms, with 0.86±0.74 mm vs 0.86±0.73 mm, respectively (p=0.71), per 0.5 mm overexpansion. For 3.00 mm stent platform, maximal elongation was 4.31±1.47 mm after up to 5.5 mm overexpansion. For 3.50 mm platform, maximal elongation was 2.87±0.94 mm after up to 5.5 mm overexpansion. Thirty-six clinical cases were analysed, of which 22 (61%) were performed in the distal left main. Post-dilation was performed with 0.98±0.36 mm absolute overexpansion, resulting in 2.22±1.35 mm elongation, as compared to nominal stent length.

Conclusions: Overexpansion by POT results in proximal stent elongation. This has to be considered once the stent length is selected and the stent is positioned, especially in the left main stem, where proximal overexpansion is marked and accurate ostial landing is critical.

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