Optical Frequency Domain Imaging Research Articles

Predictors of late lumen enlargement after drug-coated balloon angioplasty for de novo coronary lesions.

Late lumen enlargement (LLE) - a positive remodelling phenomenon - after drug-coated balloon (DCB) angioplasty for stable coronary disease contributes to a lower restenosis rate. However, lesion characteristics promoting LLE remain unclear. This study aimed to investigate predictive lesion characteristics for LLE using serial optical frequency domain imaging (OFDI) following DCB angioplasty for de novo coronary artery lesions. This retrospective, single-centre observational study included patients with angina pectoris who underwent paclitaxel-coated balloon angioplasty without stenting under OFDI guidance as well as follow-up OFDI. OFDI endpoints were lumen volume, plaque phenotype, and procedure-associated dissection. LLE was defined as a ≥10% increase in the lumen volume of the treated lesion at follow-up. Between August 2016 and December 2019, among patients with successful DCB angioplasty, 108 lesions (83 patients) had available follow-up imaging after a median of 6.1 months. LLE was detected in 44 (40.7%) lesions. Fibrous/fibrocalcific and layered plaques had significantly larger lumen volumes at follow-up than immediately after the index procedure, whereas lipid plaques exhibited no significant difference. Medial dissection with an arc >90° revealed an increased lumen volume. Multivariate analysis showed that layered plaques (odds ratio [OR] 8.73, 95% confidence interval [CI]: 1.92-39.7; p=0.005) and medial dissection with an arc >90° (OR 4.65, 95% CI: 1.63-13.3; p=0.004) were independent LLE predictors. Layered plaques and extensive medial dissection after DCB angioplasty were associated with higher LLE occurrence in de novo coronary lesions. These findings may be clinically applicable to DCB therapeutic strategies based on plaque features.

High-frequency optical coherence tomography for endovascular management of cerebral aneurysms.

Endovascular management of intracranial aneurysms has become the mainstay of treatment in recent years; however, retreatment rates remain as high as 1 in 5. High-frequency optical coherence tomography (HF-OCT) is an emerging imaging modality for the assessment, treatment and follow-up of cerebral aneurysms. EMBASE and SCOPUS databases were searched for studies relating to the management of intracranial aneurysm with OCT. A combination of keywords were used including 'cerebral aneurysm', 'intracranial aneurysm', 'high-frequency optical coherence tomography', 'optical coherence tomography', and 'optical frequency domain imaging'. There were 23 papers included in this review. For the assessment of intracranial aneurysm, OCT was able to accurately assess aneurysm morphology as well as detailed analysis of arterial wall layers. During IA treatment, OCT was used to assess and troubleshoot stent placement to optimise successful isolation from the circulation. In the follow-up period, endothelial growth patterns were visualised by OCT imaging. OCT shows promise for the treatment of IAs at all stages of management. Due to the novel development of HF-OCT, there is limited longitudinal data in human studies. Further research in this area is required with a focus specifically on long-term treatment outcomes in humans.

The observation of below-the-knee artery by optical frequency domain image and angioscopy: a case series

Abstract Background Endovascular treatment (EVT) is a well-established treatment for patients with chronic limb-threatening ischaemia, and below-the-knee (BTK) artery is its main target, although the re-intervention rate is still high. Understanding of the characteristics of BTK artery atherosclerosis would be required to overcome this issue. In this case series, we elucidated the characteristics of non-stenotic BTK artery atherosclerosis in the patients who received EVT of the superficial femoral artery (SFA) using optical frequency domain imaging (OFDI) and angioscopy. Case summary We presented five patients who underwent EVT of SFA and subsequent observation of ipsilateral BTK artery using OFDI and angioscopy. Patients one and two had advanced atherosclerosis; however, patients three, four, and five had only mild atherosclerosis. Discussion All patients had multiple risk factors for atherosclerosis and stenosis/occlusion of the SFA and ipsilateral BTK arteries. Furthermore, some patients had several other atherosclerotic vascular diseases suggesting the presence of advanced systemic atherosclerosis. On the other hand, some patients with multiple BTK artery stenosis/occlusion did not have advanced atherosclerosis in the examined BTK artery. The absence of significant atherosclerosis in a BTK artery in patients with multiple stenoses or occlusion in other ipsilateral BTK arteries may suggest some mechanism of vessel occlusion other than atherosclerosis. Further investigations are needed to clarify the mechanism.

TCT-136 Optical Frequency Domain Imaging Versus Intravascular Ultrasound in Percutaneous Coronary Intervention in Patients With Acute Coronary Syndrome: Primary Result From the OPINION ACS Trial

TCT-136 Optical Frequency Domain Imaging Versus Intravascular Ultrasound in Percutaneous Coronary Intervention in Patients With Acute Coronary Syndrome: Primary Result From the OPINION ACS Trial

Evaluation of the thickness of coronary calcium by 60-MHz intravascular ultrasound: head-to-head comparison with optical frequency domain imaging.

The region behind the coronary calcium could not be visualized by intravascular ultrasound (IVUS) because of acoustic shadow. However, some pathological studies have shown that IVUS delineated the vessel border behind thin coronary calcium sheets. This study aimed to reveal whether recent IVUS can visualize the region behind thin coronary calcium sheets. Using 534 cross-sectional optical frequency domain images (OFDI), including severe calcified coronary lesions, calcium sheet thickness was measured by every 1°. Accordingly, the visibility of the vessel border behind the coronary calcium sheet was evaluated using 60-MHz IVUS images, which were longitudinally linked with OFDI ones. After carefully coordinating with the axial position, the association between the IVUS-derived permeability of the coronary calcium sheet and calcium thickness was evaluated. The maximum and mean calcium thickness by OFDI was 0.88 ± 0.39 and 0.62 ± 0.30mm, respectively. By 60-MHz IVUS, 12.1% of the coronary calcium sheets had permeable segments. Comparing between OFDI and IVUS images, 48.6% of the coronary calcium sheets with maximum thickness ≤ 0.3mm were sometimes permeable by 60-MHz IVUS, whereas most > 0.5mm thick calcium sheets were impermeable. In the receiver operating characteristic curve analysis, the best cutoff values for the maximum and mean thickness of permeable calcium were 0.48 and 0.31mm, respectively. Thus, 60-MHz IVUS can occasionally visualize the region behind a thin coronary calcium sheet. When using 60-MHz IVUS, this finding may be a predictive marker of calcium sheet with a thickness of < 0.5mm.

Importance of optimal rewiring guided by 3-dimensional optical frequency domain imaging during double-kissing culotte stenting demonstrated through a novel bench model

The usefulness of optical frequency domain imaging (OFDI) guidance on two-stenting at left main bifurcation has not been evaluated. Here, we used a novel bench model to investigate whether pre-defined optimal rewiring with OFDI-guidance decreases acute incomplete stent apposition (ISA) at the left main bifurcation segment. A novel bench simulation system was developed to simulate the foreshortening and overlapping of daughter vessels as well as left main bifurcation motion under fluoroscopy. Double-kissing (DK) culotte stenting was performed using the novel bench model under fluoroscopy with or without OFDI-guidance. In the OFDI-guidance group, if the guidewire did not pass through the pre-defined optimal cell according to the 3-dimensional OFDI, additional attempts of rewiring into the jailed side branch were performed. The success rate of optimal jailed side branch rewiring after implantation of the first and second stent under OFDI-guidance was significantly higher than that under only angio-guidance. After completion of the DK-culotte stenting, the incidence and volume of ISA at the bifurcation segment in the OFDI-guidance group was significantly lower than that in the angio-guidance group. Online 3-dimensional OFDI-guided DK-culotte stenting according to a pre-defined optimal rewiring point might be superior to only angio-guided rewiring for reducing ISA at the bifurcation.

Prediction of the debulking effect of rotational atherectomy using optical frequency domain imaging: a prospective study

This study determined the predictive accuracy of optical frequency domain imaging (OFDI) on debulking effects of rotational atherectomy (RA) and compared the predictive accuracy of OFDI catheter-based with Rota wire-based prediction methods. This prospective, single-center, observational study included 55 consecutive patients who underwent OFDI-guided RA. On pre-RA OFDI images, a circle, identical to the Rota burr was drawn at the center of the OFDI catheter (OFDI catheter-based prediction method) or wire (wire-based prediction method). The area overlapping the vessel wall was defined as the predicted ablation area (P-area). The actual ablated area (A-area) was measured by superimposing the OFDI images before and after RA. The overlapping P-area and A-area were defined as overlapped ablation area (O-area), and the predictive accuracy was evaluated by %Correct area (O-area/P-area) and %Error area (A-area − O-area/A-area). The median %Correct and %Error areas were 47.8% and 41.6%, respectively. Irrelevant ablation (low %Correct-/high % Error areas) and over ablation (high %Correct-/high % Error areas) were related to deep vessel injury and intimal flap outside the P-area. The predictive accuracy was better in the OFDI catheter-based prediction method than the wire-based prediction method in the cross sections where the OFDI catheter and wire came in contact. However, it was better in the latter than the former where the OFDI catheter and wire were not in contact. OFDI-based simulation of the RA effect is feasible though accuracy may be affected by the OFDI catheter and wire position. OFDI-based simulation of RA effect might reduce peri-procedural complications during RA.

The Height and Mobility of Protruding Plaque After Carotid Artery Stenting Are Associated with Postoperative Ischemic Lesions.

Tissue protrusion (TP) is a possible cause of cerebral infarction after carotid artery stenting (CAS). Using optical frequency domain imaging (OFDI) and angioscopy, we investigated the relationship between the morphological features of TP and postoperative new ischemic lesions on magnetic resonance imaging (MRI)-diffusion weighted imaging (DWI) after CAS. Fifty patients who underwent CAS and subsequent poststenting intravascular evaluation using both OFDI and angioscopy were included. CAS was performed for proximal protection via the femoral artery approach, and intravascular evaluation with OFDI and angioscopy were performed after stent placement. We compared the background and poststenting intravascular findings between patients with and without postoperative new ischemic lesions on MRI-DWI. TP was observed in 42 patients (84%), and postoperative new ischemic lesions on MRI-DWI were observed in 32 patients (64%). The frequency of TP did not differ between the 2 groups, but the height of TP was higher in the DWI-positive group (0.62mm vs. 0.29mm, P=0.0028), and mobile TP was observed only in the DWI-positive group. The height of TP (P= 0.023) was an independent predictor of new periprocedural ischemic brain lesions after CAS, and its cut-off value for mobility was 0.55mm on the receiver operating characteristic curve (area under the curve, 0.93). The height of TP on OFDI and mobile-TP on angioscopy after CAS were associated with postoperative new ischemic lesions on MRI-DWI. The intravascular evaluation using OFDI and angioscopy could be helpful for a detailed evaluation of TP.

Spontaneous Aneurysmal Degeneration Healing After Fluoropolymer-Based Drug-Eluting Stent Placement Observed Using Optical Frequency Domain Imaging.

Spontaneous Aneurysmal Degeneration Healing After Fluoropolymer-Based Drug-Eluting Stent Placement Observed Using Optical Frequency Domain Imaging.

Automatic detection and visualization system for coronary artery calcification using optical frequency domain imaging

Automatic detection and visualization system for coronary artery calcification using optical frequency domain imaging

Neointimal characteristic changes following drug-coated balloons in lesions with repeated revascularization.

Since their emergence, drug-coated balloons (DCBs) have been used widely to treat in-stent lesions with coronary artery disease (CAD). However, despite their superior efficacy to balloon angioplasty, how DCBs affect neointimal characteristics is poorly understood. We aimed to assess the neointimal characteristic changes following DCB treatment. Using optical frequency domain imaging (OFDI), we serially observed the in-stent lesion site just after and 1 year after DCB angioplasty in 12 lesions of 11 patients with repeated revascularization. Neoatherosclerosis was defined as lipid-laden neointima with or without calcification in the stented lesion. Progression or regression of neoatherosclerosis, newly formed neointimal calcification, newly formed uncovered strut and newly formed evagination were assessed. Tiny tissue protrusion was also recorded as mushroom-like protrusion. Underlying stents were first-generation (n = 5) or newer (n = 7) drug-eluting stents (DESs) with implantation durations ranging from 1 to 15 years (median 8 years). Surprisingly, two-thirds of the lesions (67%, 8 of 12) showed progression of neoatherosclerosis, while a quarter of lesions (25%, 3 of 12) showed regression of neoatherosclerosis. The maximal lipid arc increased from 122° to 174°. Newly formed neointimal calcification was observed in 2 of 12 lesions (16%). Newly formed uncovered struts (33%; 4 of 12) and newly formed evaginations (33%; 4 of 12) were not rare. Mushroom-like protrusion was found in a quarter of lesions (25%; 3 of 12). Our study demonstrated that a considerable number of lesions showed varied neointimal characteristic changes in a small number of patients. Further studies in a larger population are needed to understand the clinical impact of these findings.

Relationship Between Optical Coherence Tomography-Derived In-Stent Neoatherosclerosis and the Extent of Lipid-Rich Neointima by Near-Infrared Spectroscopy and Intravascular Ultrasound: A Multimodal Imaging Study.

Background In-stent restenosis, especially for neoatherosclerosis, is a major concern following percutaneous coronary intervention. This study aimed to elucidate the association of features of in-stent restenosis lesions revealed by optical coherence tomography (OCT)/optical frequency domain imaging (OFDI) and the extent of lipid-rich neointima (LRN) assessed by near-infrared spectroscopy (NIRS) and intravascular ultrasound, especially for neoatherosclerosis. Methods and Results We analyzed patients undergoing percutaneous coronary intervention for in-stent restenosis lesions using both OCT/OFDI and NIRS-intravascular ultrasound. OCT/OFDI-derived neoatherosclerosis was defined as lipid neointima. The existence of large LRN (defined as a long segment with 4-mm maximum lipid core burden index ≥400) was evaluated by NIRS. In 59 patients with 64 lesions, neoatherosclerosis and large LRN were observed in 17 (26.6%) and 21 lesions (32.8%), respectively. Naturally, large LRN showed higher 4-mm maximum lipid core burden index (median [interquartile range], 623 [518-805] versus 176 [0-524]; P<0.001). In OCT/OFDI findings, large LRN displayed lower minimal lumen area (0.9±0.4 versus 1.3±0.6 mm2; P=0.02) and greater max lipid arc (median [interquartile range], 272° [220°-360°] versus 193° [132°-247°]; P=0.004). In the receiver operating characteristic curve analysis, 4-mm maximum lipid core burden index was the best predictor for neoatherosclerosis, with a cutoff value of 405 (area under curve, 0.92 [95% CI, 0.83-1.00]). In multivariable logistic analysis, only low-density lipoprotein cholesterol (odds ratio, 1.52 [95% CI, 1.11-2.08]) was an independent predictor for large LRNs. Conclusions NIRS-derived large LRN was significantly associated with neoatherosclerosis by OCT/OFDI. The neointimal characterization by NIRS-intravascular ultrasound has potential as an alternative method of OCT/OFDI for in-stent restenosis lesions.

Stent Size Reduction Phenomenon in Optical Frequency Domain Imaging Using CO2.

Stent Size Reduction Phenomenon in Optical Frequency Domain Imaging Using CO2.

Abstract 12487: Ex Vivo Assessments of Human Nodular Calcification: Optical Frequency Domain Imaging and Histopathology

Introduction: It has been reported that a nodular calcification is associated with a calcified nodule and the reappearance of in-stent failure after percutaneous coronary intervention. Hypothesis: This study evaluated characteristics of nodular calcification on optical frequency domain imaging (OFDI) image in comparison to histopathology. Methods: One hundred and seven matched OFDI and histopathological cross-sections from 13 coronary arteries of 5 human autopsy hearts were evaluated. In histopathological assessment, a nodular calcification was defined as a fragmented calcification with accumulated fibrin. In OFDI analysis, calcification arc, shape of luminal surface, lumen side shape of calcification, irregularity of lumen surface, and irregularity of calcification surface of lumen side were analyzed in each OFDI image. Results: There were 10 nodular calcifications and 97 non-nodular calcifications in histopathological slices. The calcification arc was significantly smaller in nodular calcification than in non-nodular calcification [89.5° (56.4-108) vs. 126° (82.0-190), p =0.02]. OFDI features of a nodular calcification were characterized by a convex shape of the luminal surface (90.0% in nodular calcifications vs. 6.2% in non-nodular calcifications, p &lt;0.01), a convex shape of calcification (90.0% vs 18.6%, p &lt;0.01), an irregular luminal surface (50.0% vs 0%, p &lt;0.01), and an irregular calcification surface of lumen side (60.0% vs 3.1%, p &lt;0.01). Conclusion: This study suggests that OFDI has a potential capability to distinguish between nodular calcification and non-nodular calcification based on angle of calcification, shape and irregularity of luminal surface and those of calcification.

Abstract 10434: Very Late Stent Thrombosis Caused by Rupture of In-Stent Neoatherosclerosis 15-Years After Bare Nitinol Stent Implantation in Superficial Femoral Artery Visualized With Multimodality Imaging

A 77-year-old man complained of intractable rest pain in his left leg, which occurred one week before hospital admission. His past medical history included diabetes mellitus and history of smoking. He was prescribed cilostazol for treatment of peripheral vascular disease. He underwent endovascular therapy (EVT) 15-years earlier with a bare nitinol stent (BNS) implantation in his left superficial femoral artery (SFA), and no restenosis was detected by annual duplex ultrasound (DUS) follow-up until this session. DUS observed restenosis with 14.8 peak systolic velocity ratio, and initial angiography ( Panel A , white arrow) revealed subtotal occlusion at the stented lesion. Intravascular angioscopy ( Panel C ) demonstrated disrupted cavity with red thrombus attached. Optical frequency domain imaging (OFDI) ( Panel D ) and intravascular ultrasound (IVUS) ( Panel E ) demonstrated fibrous cap disruption with a clear cavity formed inside the plaque (6 to 11 o’clock in Panel D and E), as well as thin sheet calcification. The other side (11 to 6 o’clock) shows a signal rich region with high attenuation that indicates fibroatheroma. The lesion was diagnosed as very late stent thrombosis (VLST) because multimodality images revealed rupture of in-stent neoatherosclerosis with red thrombus attached. After successful vessel preparation with a high-pressure 6mm balloon, 6 mm drug-coated balloons were used. The completion angiogram revealed an acceptable result with neither residual stenosis nor flow-limiting dissection ( Panel B ). Neoatherosclerosis has been reported as one of the major causes of VLST in the coronary arteries; however, it has rarely been reported in the peripheral arteries. This case illustrates valuable direct visualization with multimodality imaging of a case with VLST caused by rupture of in-stent neoatherosclerosis 15-years after BNS implantation, and the value of multimodality imaging for comprehensive evaluation to diagnose the mechanism of VLST in SFA.

Comparison of Six Different Percutaneous Coronary Intervention Guidance Modalities.

Background: New randomized trials and modalities in guiding percutaneous coronary intervention (PCI) have become available. Objective: We aimed to compare the clinical outcomes of coronary angiography (CAG), intravascular ultrasound (IVUS), optical coherence tomography (OCT), fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), and optical frequency domain imaging (OFDI)-guided PCI. Methods: A network meta-analysis was performed to compare different PCI guidance modalities. The clinical outcomes included major adverse cardiovascular events (MACE), all-cause death, myocardial infarction (MI), and target vessel/lesion revascularization (TVR/TLR). Odds ratio (OR) and corresponding 95% credible interval (CrI) were calculated. Results: Thirty-six randomized trials, including 19,042 patients, were included. In comparison with CAG, IVUS significantly reduced MACE (OR: 0.71; 95% CrI: 0.57 to 0.86) and TVR/TLR (OR: 0.53; 95% CrI: 0.43 to 0.66). MACE (OR: 1.44; 95% CrI: 1.02 to 2.08) and TVR/TLR (OR: 1.87; 95% CrI: 1.04 to 3.71) were significantly increased in the FFR group, compared with IVUS group. There were no significant differences in MACE or TVR/TLR among the left guidance modality comparisons. Differences in all-cause death or MI were not observed in any comparisons. Conclusions: IVUS could reduce MACE and TVR/TLR, compared with CAG or FFR. Therefore, IVUS may be the optimal modality in guiding PCI.

Potential of optical frequency domain imaging for differentiation between early and advanced coronary atherosclerosis.

This study evaluated whether optical frequency domain imaging (OFDI) accurately distinguish between fibroatheroma (FA) and pathological intimal thickening (PIT) compared with histopathology. A total of 631 histological cross-sections from 14 autopsy hearts were analyzed for the comparison between OFDI and histological images. Of those, 190 (30%) sections were diagnosed with PIT and 120 (19%) with FA. The OFDI signal attenuation rate was calculated from an exponential. The lipid length was measured longitudinally by detection of sequential OFDI frames within a plaque segment containing lipids. The lipid arc was measured with a protractor centered in the center of the lumen. The fibrous cap thickness was defined as the minimum thickness of the signal rich band overlying PIT and FA. There was no significant difference in the OFDI signal attenuation rate between FA and PIT (3.09 ± 1.04 versus 2.79 ± 1.20, p = 0.13). However, the lipid length was significantly longer, the maximum lipid arc was significantly larger, and the fibrous cap thickness was significantly thinner in FA than in PIT (7.5 [4.3-10.3] mm versus 4.3 [2.7-5.8] mm, p < 0.0001, 125 [101-174]° versus 96 [74-131]°, p < 0.0001, and 220 [167-280] µm versus 260 [190-332] µm, p = 0.019). This study revealed OFDI may have the potential capability for discriminating FA from PIT based on the longitudinal and circumferential extent of lipid plaque, although the OFDI signal attenuation rate was similar between FA and PIT.

Clinical expert consensus document on standards for lower extremity artery disease of imaging modality from the Japan Endovascular Treatment Conference.

Imaging modalities have developed to provide precise information in the assessment of lower extremity artery disease (LEAD), including both quantitative measurements and morphological assessment. However, a lack of standardization for the evaluation methods introduces inconsistency and potential risk. This consensus documentfrom Japan Endovascular Treatment Conference (JET) summarizes the methods of measurement and assessment of intravascular ultrasound (IVUS), optical frequency domain imaging (OFDI), and angioscopy. We propose standardized approaches for the evaluation of these modalities in endovascular therapy (EVT).

Effect of Crack Patterns in Calcified Plaque on Lumen Area after Stenting for a Severe Calcified Coronary Artery (from the Optical Frequency Domain Imaging-Guided Percutaneous Coronary Artery Intervention for Calcified Lesion Registry).

Background Severely calcified coronary artery stenting remains a challenge due to stent thrombosis, target vessel failure, and higher mortality. Moreover, optimal vessel preparation for calcified plaque with a crack formation pattern has not been established yet. We aimed to identify the effect of crack formation in calcified plaque in the coronary artery on the lumen area after stenting. Materials and Methods We evaluated 50 consecutive patients undergoing drug-eluting stent implantation for severely calcified lesions by using optical frequency domain imaging (OFDI) (54 lesions); we analyzed OFDI image slices every 3 mm and evaluated the segments of 242 images in those who had the arc of calcium more than 180°. Crack formation in calcified plaque was classified into three types: type 0, no cracks; type 1, no dissection between calcified plaque and vessel wall; and type 2, any dissection between calcified plaque and vessel wall. Results Type 2 had a significantly higher area expansion ratio between preballooning and poststenting (type 0, 196% (interquartile range (IQR), 163–244); type 1, 210% (IQR, 174–244); type 2, 237% (IQR, 203–294)). Conclusions The dissection between calcified plaque and vessel wall was a significant factor affecting lumen area expansion after stenting.

Expert consensus statement for quantitative measurement and morphological assessment of optical coherence tomography: update 2022.

In this updated expert consensus document, the methods for the quantitative measurement and morphological assessment of optical coherence tomography (OCT)/optical frequency domain imaging images (OFDI) are briefly summarized. The focus is on the clinical application and the clinical evidence of OCT/OFDI to guide percutaneous coronary interventions.