Comparison between optical coherence tomography and intravascular ultrasound in detecting neointimal healing patterns after stent implantation

Background: The amount of data comparing intravascular ultrasound (IVUS) and optical coherence tomography (OCT) for the detection of stent coverage in clinical settings is limited. Aim: To make a qualitative and quantitative assessment of the vascular healing patterns in patients after stent implantations visualised by both IVUS and OCT. Methods: Images were obtained in patients with clinical symptoms of angina, who had had a bare metal stent implanted in the previous 12 months. Angiography, IVUS and OCT were performed in 14 coronary arteries. Measurements of stent, lumen and neo-intima areas and dimensions were performed in stented regions and in both 10 mm references. IVUS, OCT, and angiographic data were compared in matched regions. Off-line analyses were performed by an independent core lab. Results: 14 stents were imaged without any procedural complications. The nominal stent length was 28 +/- 4.5 mm. OCT was the most accurate technique for assessing stent length (28.12 +/- 6.8 mm), while QCA underestimated length due to foreshortening (22.16 +/- 6.39 mm) and IVUS was vulnerable to random error due to discontinuous pullbacks and vessel movements (24.21 +/- 7.90 mm). Minimum lumen area (MLA) and minimum lumen diameter (MLD) in reference sites were comparable in IVUS and OCT, whereas there were significant differences between these two modalities for MLA (3.30 +/- 1.49 vs. 2.19 +/- 1.30 mm(2), p = 0.0046) and for MLD (2.42 +/- 0.51 vs. 1.58 +/- 0.56 mm(2), p = 0.0023) in stented segments. There was a slight overestimation of lumen volume (130.18 +/- 70.61 vs. 117.82 +/- 67.02 mm(3), p = 0.7256), a marked overestimation of stent volume (179.29 +/- 97.58 vs. 226.46 +/- 108.76 mm(3), p = 0.0544) and a statistically significant difference in the neointima volume (49.11 +/- 39.70 vs. 108.64 +/- 43.77 mm(3), p = 0.0060) by IVUS compared to OCT. Mean neointima burden in IVUS was much smaller than in OCT (20.79 +/- 14.27% vs. 58.16 +/- 18.25%, p = 0.0033). Conclusions: OCT can precisely quantify struts coverage and is more accurate than IVUS in the assessment of vascular healing in patients after stent implantation.