Comparison of optical coherence tomography and intravascular ultrasound for the assessment of in-stent tissue coverage after stent implantation

Abstract

Aims: At present there exists no direct comparative data for the detection of in-stent tissue coverage as assessed by intravascular ultrasound (IVUS) and optical coherence tomography (OCT) in clinical settings. To explore this subject, we investigated the correlation between the IVUS and OCT measurements derived from a contemporary population.

Methods and results: The present study includes 20 patients who had stents imaged at a six months follow-up with both IVUS and OCT, acquired with an automated pull-back. Off-line analyses were done by an independent validated Core-Lab (RHR, Rome, Italy). Measurements of stent length obtained by IVUS and OCT were 16.3+/-3.0 mm and 16.2+/-3.8 mm respectively (p=0.82) and were similar to nominal length (16.3+/-3.3 mm). Luminal area in the OCT image set was lower than that obtained in the corresponding IVUS image set (3.83+/-1.60 mm2 vs 4.05+/-1.44 mm2, p<0.001), while stent area was significantly higher when measured by OCT (6.61+/-1.39 mm2 vs 6.17+/-1.07 mm2, p<0.001). The percentage of tissue coverage measured by IVUS was lower than that measured in the corresponding OCT image sets (35.5+/-16.4% vs 43.4+/-16.1%, p<0.001). Correlation coefficients were high for repeated OCT measurements by two different observers (r=0.99).

Conclusions: OCT can quantify in-stent coverage and detect strut healing with high reproducibility. IVUS tends to underestimate the percentage of in-stent tissue coverage as compared to OCT.