Dual versus tapered reference benchmarks for assessing stent expansion using optical coherence tomography

Matt Sibbald, Ali Hillani, Jorge Chavarria, Gustavo Dutra, Mognee Alameer, Urmi Sheth, Natalia Pinilla, Tej Sheth

Background: Intravascular imaging studies frequently highlight stent under expansion as a major predictor of repeat interventions. However, no consistent method to identify stent expansion exists. Two types of benchmarks are routinely available, dual and tapered reference, with unclear differences between them. We then sought to compare stent expansion using two different methods of reference benchmarking on Optical Coherence Tomography (OCT) imaging, one involving both proximal and distal stent edges (dual reference) and the other a computed estimate of reference size for each frame (tapered reference).

Methods: We retrospectively analyzed stent expansion in 249 OCTs of patients undergoing percutaneous intervention for de novo chronic coronary disease or acute coronary syndromes. We compared stent expansion using dual versus tapered benchmarks.

Results: Suboptimal expansion (<90%) occurred in 71% of cases when using dual reference and 60% when using tapered reference (χ2=143, p<0.0001). Agreement in identifying suboptimal expansion between dual and tapered modes was 88% (k=0.74, p<0.0001). Dual reference identified suboptimal expansion in 28 cases (11%) where expansion was optimal by tapered mode; whereas tapered mode identified suboptimal expansion in only 2 cases (<1%) where expansion was optimal by the dual reference approach.

Conclusion: In this real world series, identification of suboptimal expansion by OCT imaging was frequent, with high agreement between dual and tapered benchmarks. Differences of sufficient magnitude to change post dilation strategy were present in 1 out of every 10 cases.