Author + information
- Jinyong Ha, PhD,
- Jung-Sun Kim, MD,
- Gary S. Mintz, MD,
- Byeong-Keuk Kim, MD,
- Dong-Ho Shin, MD, MPH,
- Young-Guk Ko, MD,
- Donghoon Choi, MD,
- Yangsoo Jang, MD and
- Myeong-Ki Hong, MD∗ ()
- ↵∗Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Korea.
The relationship between 3-dimensional (3D) optical coherence tomography (OCT) and fractional flow reserve (FFR) evaluation of a jailed side-branch ostium has not been investigated. Therefore, after a single-stent cross-over technique was used to treat bifurcation stenoses, we used OCT to image the stented main vessel, performed 3D OCT reconstruction of the orifice of jailed side-branch ostia, and compared the 3D OCT analysis with FFR measurements of the side-branch.
We enrolled 90 patients with bifurcation lesions who underwent both OCT of the main vessel and FFR of jailed side branches after a single-stent crossover technique. The inclusion criteria were the following: a side-branch ostium with a reference vessel diameter ≥2 mm; lesion length <10 mm by visual estimation; and TIMI (Thrombolysis In Myocardial Infarction) flow grade 3.
OCT imaging of the target lesion was performed using a frequency-domain OCT system (C7-XR OCT imaging system, St. Jude Medical, St. Paul, Minnesota). The OCT cross-sectional images acquired by the C7-XR system were processed offline using ImageJ software (National Institutes of Health, Bethesda, Maryland) and then imported into a 3D volume-rendering program (OsiriX 3.9.4, The OsiriX Foundation, Geneva, Switzerland). Side-branch minimal lumen area (MLA) was calculated with the following steps. First, the most normal-looking cross section of the side branch (Figs. 1A and 1B) perpendicular to the expected blood flow direction was selected. Next, the MLA of side branch was calculated using the multiplanar reconstruction (MPR) viewer supported in the OsiriX volume-rendering program. The 3D MPR viewer generates an MPR slice in any position and orientation through the 3D volume (Fig. 1C). As the blue line in Figure 1C represents the location of the orthogonal plane in Figure 1D, the position and orientation of the blue line was moved so that the blue line was perpendicular to the expected blood flow direction within the side branch. Finally, the MLA of the side branch was measured in the MPR slice (Fig. 1D). MLA measurement by OCT was highly reproducible (r = 0.996, intraclass correlation coefficient: 0.994 for intraobserver; r = 0.994, intraclass correlation coefficient: 0.995 for interobserver agreement).
After successful stent implantation into the main vessel across the side branch, the 0.014-inch pressure guidewire (St. Jude Medical) was applied with an intracoronary bolus administration of adenosine (80 μg in the left coronary artery and 40 μg in the right coronary artery) to induce maximal hyperemia. The jailed side branch was considered functionally significant when the FFR was ≤0.8.
Initially, 90 patients with 90 lesions were studied. However, 8 lesions were excluded due to poor quality of the reconstructed 3D OCT images. Therefore, 82 lesions in 82 patients were finally included in this study. A functionally significant stenosis was observed in 20 (24.4%) jailed side branches. Using receiver-operating characteristic curve analysis, the best cutoff value of the 3D OCT reconstructed side-branch MLA was 2.05 mm2 for predicting a functionally significant stenosis (area under the curve: 0.81, 95% confidence interval: 0.71 to 0.91; p < 0.001; sensitivity: 71.0%; specificity 75.0%; positive predictive value: 54.5%; negative predictive value: 91.5%) (Figs. 1E and 1F).
In conclusion, 3D OCT had a modest ability to predict the functional significance for borderline lesions caused by a jailed side-branch ostium.
Please note: This study was supported by a faculty research grant of Yonsei University College of Medicine (#6-2010-0018); a grant from the Korea Healthcare Technology Research and Development Project, Ministry for Health, Welfare and Family Affairs, Republic of Korea (#A085012 and #A102064); a grant from the Korea Health 21 Research and Development Project, Ministry of Health and Welfare, Republic of Korea (#A085136); and the Cardiovascular Research Center, Seoul, Korea. The authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Ha and J. S. Kim contributed equally to this paper. Morton Kern, MD, served as Guest Editor for this paper.
- American College of Cardiology Foundation