Yoshitaka Shiratori

Quantitative optical coherence tomography analysis for late in-stent restenotic lesions.

Coronary optical coherence tomography (OCT) has the potential to identify in-stent neoatherosclerosis, which is a possible risk factor for late acute coronary events after drug-eluting stent implantation. The purpose of this study was to investigate differences between mid-term and late in-stent restenosis after stent implantation by quantitative and semiautomated tissue property analysis using OCT. In total, 1063 OCT image frames of 16 lesions in 15 patients were analyzed. This included 346 frames of 6 lesions in late in-stent restenosis, which was defined as restenosis that was not detected at 6 to 12 months but ≥ 12 months after follow-up coronary angiography. Signal attenuation was circumferentially analyzed using a dedicated semiautomated software. Attenuation was assessed along 200 lines delineated radially for analysis of the in-stent restenotic lesions (between the lumen and stent contours). All lines were anchored by the image wire to avoid artifacts resulting from wire location. Stronger signal attenuation at the frame level (2.46 ± 0.78 versus 1.47 ± 0.32, P < 0.001) and higher maximum signal intensity at the lesion level (9.19 ± 0.19 versus 8.84 ± 0.32, P = 0.018) were observed in late in-stent restenotic lesions than in mid-term in-stent restenotic lesions. OCT demonstrated stronger signal attenuation and higher maximum signal intensity in late in-stent restenotic lesions than in mid-term in-stent restenotic lesions, indicating the possibility of neoatherosclerosis.

Quantitative coronary optical coherence tomography image analysis for the signal attenuation observed in-stent restenotic tissue

primary pulmonary hypertension has been published by Rothman et al. [21]. Thus, a review of the epidemiological literature supports the assertion that phentermine has not been implicated in producing primary pulmonary hypertension. The same considerations discussed above apply to the statement in the PDR that “the possibility of an association between valvular heart disease and the use of phentermine alone cannot be ruled out”. At the time the labelwaswritten, thatwas an appropriately cautious statement. However, as we discussed in our reply to Yosefys original letter, further researchhas failed tofindanassociationof phenterminewithVHD[5], an assessment that is shared with by The American College of Cardiology/ American Heart Association Task Force on Practice Guidelines [6]. In our opinion, although the PDR is a valuable resource for information on medications, the PDR entry for phentermine is overly cautiouswhen considered in the context of published reports. In viewof the worsening worldwide obesity epidemic and of the known cardiac risks obesity imposes, it is fortunate that physicians have available to them a medication such as phentermine, which, in fifty years of widespread use, has proven to be remarkably safe. The drug is effective and inexpensive, costing far less thanmore recentlyapproveddrugs [13]. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology [22].

Quantified coronary frequency domain optical coherence tomography signal analysis for the evaluation of erythrocyte-rich thrombus: ex-vivo validation study

Previous study has demonstrated that erythrocyte-rich thrombi contain more inflammatory cells and reflect high thrombus burden, leading to impaired myocardial reperfusion in myocardial infarction. The aim of this study is to investigate the utility of quantified frequency domain optical coherence tomography (FD-OCT) signal analysis in evaluating the erythrocyte-rich thrombus with ex-vivo materials. We evaluated 54 specimens of coronary artery thrombus obtained by thrombectomy catheter from 8 patients who underwent primary percutaneous coronary intervention. The thrombi were immersed in saline immediately after thrombectomy and FD-OCT image acquisition was performed ex-vivo. Quantitative analysis for all contiguous frames was performed by the dedicated automated software (OCT system software, Light Lab Inc.). For the maximum thrombus area, mean signal intensity (MSI) and normalized standard deviation of signal (NSD) was evaluated. All thrombi were stained using double staining of phosphotungstic acid—hematoxylin and eosin to enable automatic extraction of erythrocyte from fibrin. Computer-assisted analysis was performed using dedicated image processing software (WinROOF, Mitani Corp., Tokyo, Japan) for color identification of the erythrocyte area. Erythrocyte-rich thrombus, defined as % erythrocyte [(erythrocyte area/total thrombus area) × 100] ≥ 10%, showed significantly lower MSI [4.39 ± 0.24 vs. 4.74 ± 0.35, p = 0.002] than that of <10%. The cut-off point for prediction of erythrocyte-rich thrombus was defined as MSI ≤ 4.56, sensitivity: 87.5%, specificity: 82.9%, area under the curve: 0.836, respectively). The present ex-vivo study suggested the utility of quantified FD-OCT signal analysis on the detection of erythrocyte-rich thrombus.

Serial optical coherence tomography assessment of malapposed struts after everolimus-eluting stent implantation. A subanalysis from the HEAL-EES study ☆

BACKGROUND Incomplete stent apposition (ISA) is related to stent thrombosis, which is a serious adverse event. We aim to assess the time-course of ISA after 2nd generation everolimus-eluting stent (EES) implantation. METHODS In HEAL-EES study, we enrolled 36 patients who underwent percutaneous coronary intervention (PCI) with EES. OCT imaging was performed at baseline and follow-up. Patients were randomized 1:1:1 into 3 groups according to the time in which follow-up was performed: group A (6-month), group B (9-month), and group C (12-month). In this subanalysis, patients who had ISA segments at baseline and/or follow-up OCT were analyzed. RESULT At baseline, among 41 lesions in 36 patients, 20 lesions in 18 patients had ISA segments and were analyzed. At baseline, there were 3.0% ISA struts in group A (n=8), 2.8% in group B (n=4), and 4.5% in group C (n=8). At follow-up, ISA struts were present in 0.09%, 0.16% and 0.64%; respectively in groups A, B, and C. At follow-up, there was a significant decrease in the frequency of ISA: group A 3.0% vs. 0.09% (p<0.001), group B 2.8% vs. 0.16% (p<0.001), and group C 4.5% vs. 0.64% (p<0.001). In group A, there was one late acquired ISA at follow-up. CONCLUSIONS In patients undergoing 2nd generation EES implantation, area of acute ISA assessed by OCT, was almost resolved at 6-month follow-up.

Incidence and significance of the pseudo stent strut in optical coherence tomography analysis for coronary artery stents

Introduction: Quantitative optical coherence tomography (OCT) analysis is about to be relevant for the correct assessment of incomplete stent apposition which can result to late stent thrombosis. Nevertheless, the pseudo stent struts (PS), which show the strong signal same as the true strut, are sometimes seen at odd positions in the lumen and locate at the same distance from the image wire as a true strut. PS may be produced by the distorted beam and interfere accurate analysis. Our aim was to investigate the incidence of PS. Methods: We created a simple phantom model (2.5 mm-coronary artery stent apposed in 2.5-mm silicon tube). OCT pullback images at 1 mm/sec were obtained with an eccentric imagewire position for 5 times with different 5 pieces of imagewire. The strut location was recognized by the strong signal. Of these, PS was defined as: an irregularity of the alignment of strut locations; the difference in the strut-wire distance with one of the adjacent struts is within 20 micron. Strut contour with and without PS were delineated by semi-automated dedicated software with cubic spline interpolation, and symmetry index (= Min/Max diameter) was calculated. Results: In the phantom with Cypher stent and Tsunami stent, a pseudo strut reflection was observed in 71 of 7112 (1%) frames and 43 of 10302 (0.4%) frames, respectively. The PS incidence was the highest at fifth pull-back images. The symmetry index was significantly higher in strut contours without pseudo strut (0.95±0.02 versus 0.83±0.07, p<0.001). Conclusion: PS may mislead to the wrong data of clinical OCT analysis, in spite of the infrequency. When one starts to use the new image modality, one should be careful if there is some artifact which can affect on the data of the clinical investigations.