Predictor and Mid-Term Outcome of Clinically Significant Thrombocytopenia After Transcatheter Aortic Valve Selection.

BACKGROUND: The frequency and predictors of thrombocytopenia after transcatheter aortic valve implantation (TAVI) are unclear.Methods and Results:This study enrolled 342 patients undergoing TAVI (245 with a percutaneous transfemoral approach, 65 with transfemoral surgical cutdown, and 32 with a non-transfemoral approach). Balloon-expandable and self-expanding valves were implanted in 235 and 107 patients, respectively. Platelet counts started to drop immediately, reaching a nadir 2-4 days after TAVI. Clinically significant thrombocytopenia (CSTP) was defined as a platelet count ≤50×109/L at the time of the nadir or both a platelet count between 80 and 51×109/L and a decrease in platelet count ≥50%. CSTP occurred in 16.7% patients. Approach site and TAVI valve selection significantly predicted CSTP. In multivariate analysis, independent predictors of CSTP were liver cirrhosis (odds ratio [OR] 7.22; 95% confidence interval [CI] 1.05-49.82), baseline platelet count ≤120×109/L (OR 2.98; 95% CI 1.20-7.38), multiple blood transfusions (OR 4.03; 95% CI 1.72-9.41), and the use of balloon-expandable valves (OR 2.38; 95% CI 1.04-5.46). Kaplan-Meier survival analysis with a generalized Wilcoxon test revealed that mid-term (2 years) mortality was greater for patients with than without CSTP (31.4% vs. 15.5%; P=0.008). CONCLUSIONS: TAVI-related CSTP was not rare and was associated with poor mid-term outcomes. CSTP was not only caused by patients' comorbidities and TAVI complications, but also related to TAVI procedural factors.

Predictive value of the geriatric nutritional risk index in percutaneous coronary intervention with rotational atherectomy.

The prognostic value of the geriatric nutritional risk index (GNRI) in patients undergoing percutaneous coronary intervention (PCI) with rotational atherectomy (RA) remains unknown. Therefore, we aimed to clarify whether the GNRI could predict major adverse cardiac events (MACE) in patients undergoing PCI with RA. A total of 206 patients who underwent PCI with RA from January 2009 to December 2017 were retrospectively tracked. The patients were divided into 2 groups based on the GNRI value on admission. MACE comprised all-cause death, target lesion revascularization (TLR), target vessel revascularization (TVR), and myocardial infarction. One year of follow up was completed in 95.6% of patients. During this period, 50 cases of MACE were observed (all-cause death, 32 cases; TLR, 21 cases; and TVR, 2 cases). Patients with a low GNRI (< 98) had a significantly higher incidence of MACE than did patients with a high GNRI (≥ 98) (37.9% vs. 15.5%, log-rank p < 0.05). The GNRI was an independent predictor of MACE (hazard ratio, 0.94; 95% confidence interval [CI], 0.92-0.97). Furthermore, the GNRI had better predictive power than did its components alone (i.e. body mass index and serum albumin level) (net-reclassification improvement, 0.39; 95% CI, 0.07-0.71; p = 0.01; integrated discrimination improvement, 0.02; 95% CI, - 0.01-0.04; p = 0.07). The GNRI on admission is a predictor of MACE after PCI with RA. Further studies are required to determine whether intensive medical therapy could improve clinical events, particularly cardiovascular death and revascularization, in this population.

Impact of Culprit Plaque and Atherothrombotic Components on Incomplete Stent Apposition in Patients With ST-Elevation Myocardial Infarction Treated With Everolimus-Eluting Stents　- An OCTAVIA Substudy.

BACKGROUND: The role of culprit plaque and related atherothrombotic components on incomplete stent apposition (ISA) occurrence after primary percutaneous coronary intervention (p-PCI) is unknown. METHODS AND RESULTS: ST-segment elevation myocardial infarction (STEMI) patients undergoing p-PCI with an everolimus-eluting stent were prospectively investigated with optical coherence tomography (OCT) of the infarct-related artery before, after stenting and at 9 months. OCT data, aspirated thrombus and serum inflammatory biomarkers were analyzed. 114 patients with 114 lesions were evaluated. Acute ISA occurred in 82 lesions (71.9%), preferentially in larger vessels with a median area of 0.2 mm(2). The presence of thrombus before stent implantation (odds ratio (OR) 5.5, 95% confidence interval (CI) [1.1-26.9], P=0.04) and the lipid content in the target segment (OR 1.3, 95% CI [1.0-1.5], P=0.04) independently predicted acute ISA. At 9-month follow-up, ISA persisted in 46 lesions (56.1%). The volume of acute ISA significantly predicted persistent ISA (OR 1.3, 95% CI [1.1-1.5], P=0.01). Late-acquired ISA occurred in 39 lesions (34.2%) with a median area of 0.3 mm(2). Red/mixed thrombus before stent implantation (OR 3.7, 95% CI [1.0-13.3], P=0.05) and length of the underlying ruptured plaque (OR 1.7, 95% CI [1.1-2.8] P=0.02) were independently associated with late-acquired ISA. CONCLUSIONS: In STEMI patients, culprit plaque and atherothrombotic components of the infarct-related artery significantly contribute to the onset of acute and late ISA. ISA persistence at follow-up depends on the initial volume of acute ISA.

Comparison of scanning electron microscopy and optical coherence tomography for imaging of coronary bifurcation stents.

BACKGROUND: Optical coherence tomography (OCT) is a new intracoronary imaging modality that has excellent resolution and image quality and has been used to image neointimal coverage after stent implantation. OCT has been compared to histologic, intravascular ultrasound, and scanning electron microscopy (SEM) studies. However, OCT has not been compared with SEM for imaging stent coverage over side branches. OBJECTIVE: The aim of this study was to compare OCT with SEM in imaging neointimal coverage over stent struts bridging coronary side-branch ostia. METHODS: Using a balloon-overstretch in-stent restenosis model, we deployed 38 everolimus-eluting stents across coronary bifurcations in nine pigs. We performed OCT immediately after stenting and 4 weeks later; SEM was performed after euthanizing the pigs. OCT images of each stent were compared to the corresponding SEM image. RESULTS: We analyzed OCT frames (n=111) for strut-level neointimal coverage and compared them to corresponding SEM images. The concordance correlation coefficient was 0.809 (95%CI; 0.734-0.864) and 0.951 (95%CI; 0.930-0.966) for covered and uncovered struts, respectively. CONCLUSIONS: In a non-atherosclerotic pig model, we showed strong agreement between OCT and SEM in imaging coverage of stent struts bridging side-branch ostia.

Frequency-domain optical coherence tomography assessment of unprotected left main coronary artery disease-a comparison with intravascular ultrasound.

OBJECTIVES: To investigate safety and feasibility of imaging unprotected left main (ULM) using frequency-domain optical coherence tomography (FD-OCT) compared with intravascular ultrasound (IVUS). BACKGROUND: IVUS has been used to assess and guide percutaneous coronary intervention (PCI) of ULM disease. FD-OCT offers 10-fold higher axial resolution than IVUS and its high-speed image acquisition obviates the need for proximal balloon occlusion. METHODS: We prospectively enrolled 35 consecutive patients with ULM disease. FD-OCT and IVUS assessments were attempted pre- and post-PCI and compared in regards to safety, ability to image the region of interest (ROI), number of pullbacks, volume of contrast and ability to detect malapposition, dissection, and thrombus. RESULTS: Patients were followed for 1 year when FD-OCT imaging was repeated. FD-OCT required more repeated pullbacks to image the ROI compared to IVUS. Mean lumen and stent areas were similar between FD-OCT and IVUS (11.24 ± 2.66 vs. 10.85 ± 2.47 mm(2) , P = 0.13 and 10.44 ± 2.33 vs. 10.49 ± 2.32 mm(2) , P = 0.82, respectively), whereas imaged stent length was shorter with FD-OCT. Malapposition areas and volumes were larger and more edge dissections were detected by FD-OCT. There were no clinical adverse events and no complications associated with FD-OCT at baseline and 1-year follow-up. All dissections were healed, whereas stent malapposition was still detected at follow-up. CONCLUSIONS: FD-OCT assessment of ULM is feasible and safe. Direct comparisons with IVUS reveal that FD-OCT achieved imaging completeness less often, whereas it was more sensitive in detecting malapposition and edge dissections, and similar to IVUS in the assessment of lumen and stent dimensions.

Volumetric characterization of human coronary calcification by frequency-domain optical coherence tomography.

BACKGROUND: Coronary artery calcification (CAC) presents unique challenges for percutaneous coronary intervention. Calcium appears as a signal-poor region with well-defined borders by frequency-domain optical coherence tomography (FD-OCT). The objective of this study was to demonstrate the accuracy of intravascular FD-OCT to determine the distribution of CAC. METHODS AND RESULTS: Cadaveric coronary arteries were imaged using FD-OCT at 100-µm frame interval. Arteries were subsequently frozen, sectioned and imaged at 20-µm intervals using the Case Cryo-Imaging automated system(TM). Full volumetric co-registration between FD-OCT and cryo-imaging was performed. Calcium area, calcium-lumen distance (depth) and calcium angle were traced on every cross-section; volumetric quantification was performed offline. In total, 30 left anterior descending arteries were imaged: 13 vessels had a total of 55 plaques with calcification by cryo-imaging; FD-OCT identified 47 (85%) of these plaques. A total of 1,285 cryo-images were analyzed and compared with corresponding co-registered 257 FD-OCT images. Calcium distribution, represented by the mean depth and the mean calcium angle, was similar, with excellent correlation between FD-OCT and cryo-imaging respectively (mean depth: 0.25±0.09 vs. 0.26±0.12mm, P=0.742; R=0.90), (mean angle: 35.33±21.86° vs. 39.68±26.61°, P=0.207; R=0.90). Calcium volume was underestimated in large calcifications (3.11±2.14 vs. 4.58±3.39mm(3), P=0.001) in OCT vs. cryo respectively. CONCLUSIONS: Intravascular FD-OCT can accurately characterize CAC distribution. OCT can quantify absolute calcium volume, but may underestimate calcium burden in large plaques with poorly defined abluminal borders.

Diagnosis and Prognostic Value of the Underlying Cause of Acute Coronary Syndrome in Optical Coherence Tomography-Guided Emergency Percutaneous Coronary Intervention.

Background The prognostic impact of optical coherence tomography-diagnosed culprit lesion morphology in acute coronary syndrome (ACS) has not been systematically examined in real-world settings. Methods and Results This investigator-initiated, prospective, multicenter, observational study was conducted at 22 Japanese hospitals to identify the prevalence of underlying ACS causes (plaque rupture [PR], plaque erosion [PE], and calcified nodules [CN]) and their impact on clinical outcomes. Patients with ACS diagnosed within 24 hours of symptom onset undergoing emergency percutaneous coronary intervention were enrolled. Optical coherence tomography-guided percutaneous coronary intervention recipients were assessed for underlying ACS causes and followed up for major adverse cardiac events (cardiovascular death, myocardial infarction, heart failure, or ischemia-driven revascularization) at 1 year. Of 1702 patients with ACS, 702 (40.7%) underwent optical coherence tomography-guided percutaneous coronary intervention for analysis. PR, PE, and CN prevalence was 59.1%, 25.6%, and 4.0%, respectively. One-year major adverse cardiac events occurred most frequently in patients with CN (32.1%), followed by PR (12.4%) and PE (6.2%) (log-rank P<0.0001), primarily driven by increased cardiovascular death (CN, 25.0%; PR, 0.7%; PE, 1.1%; log-rank P<0.0001) and heart failure trend (CN, 7.1%; PR, 6.8%; PE, 2.2%; log-rank P<0.075). On multivariate Cox regression analysis, the underlying ACS cause was associated with 1-year major adverse cardiac events (CN [hazard ratio (HR), 4.49 [95% CI, 1.35-14.89], P=0.014]; PR (HR, 2.18 [95% CI, 1.05-4.53], P=0.036]; PE as reference). Conclusions Despite being the least common, CN was a clinically significant underlying ACS cause, associated with the highest future major adverse cardiac events risk, followed by PR and PE. Future studies should evaluate the possibility of ACS underlying cause-based optical coherence tomography-guided optimization.

Rationale and design of the TACTICS registry: Optical coherence tomography guided primary percutaneous coronary intervention for patients with acute coronary syndrome.

BACKGROUND: Recent retrospective investigations have suggested that optical coherence tomography (OCT) enables the diagnosis of underlying acute coronary syndrome (ACS) causes such as plaque rupture, plaque erosion, and calcified nodule. The relationships of these etiologies with clinical outcomes, and the clinical utility of OCT-guided primary percutaneous coronary intervention (PCI) are not systematically studied in real-world ACS treatment settings. METHODS: The TACTICS registry is an investigator-initiated, prospective, multicenter, observational study to be conducted at 21 hospitals in Japan. A total of 700 patients with ACS (symptom onset within 24 h) undergoing OCT-guided primary PCI will be enrolled. The primary endpoint of the study is to identify the underlying causes of ACS using OCT-defined morphological assessment of the culprit lesion. The key secondary clinical endpoints are hazard ratios of the composite of cardiovascular death, non-fatal myocardial infarction, heart failure, or ischemia-driven revascularization in patients with underlying etiologies at the 12- and 24-month follow-ups. The feasibility of OCT-guided primary PCI for ACS will be assessed by the achievement rates of optimal post-procedural results and safety endpoints. CONCLUSION: The TACTICS registry will provide an overview of the underlying causes of ACS using OCT, and will reveal any difference in clinical outcomes depending on the underlying causes. The registry will also inform on the feasibility of OCT-guided primary PCI for patients with ACS.

Thrombotic events and rebleeding after hemorrhage in patients taking direct oral anticoagulants for non-valvular atrial fibrillation.

Several direct oral anticoagulants have been developed to prevent cardiogenic thrombosis in patients with atrial fibrillation, on the other hand, have the complication of bleeding. Since clinical course after bleeding with direct oral anticoagulant remains unclear, the present retrospective cohort study was to clarify the course after hemorrhage among patients receiving direct oral anticoagulants. Among all 2005 patients prescribed dabigatran, rivaroxaban, apixaban, or edoxaban between April 2011 and June 2017, subjects comprised 96 patients with non-valvular atrial fibrillation who experienced relevant bleeding during direct oral anticoagulant therapy (Bleeding Academic Research Consortium type 2 or above). The clinical course after hemorrhage was reviewed to examine whether rebleeding or thrombotic events occurred up to the end of December 2019. Gastrointestinal bleeding was the most frequent cause of initial bleeding (57 patients, 59%). Rebleeding occurred in 11 patients (4.5%/year), with gastrointestinal bleeding in 10 and subarachnoid hemorrhage in 1. All rebleeding occurred in patients who resumed anticoagulation therapy. Another significant factor related with rebleeding included past history of gastrointestinal bleeding. On the other hand, major adverse cardiac and cerebrovascular events occurred in 6 patients older than 75 years old or more (2.5%/year), with systemic thrombosis in 4 and cardiac death in 2. All 4 patients with systemic thrombosis withheld anticoagulants after index bleeding, although only 10 patients withheld anticoagulation therapy. Rebleeding should be taken care of when anticoagulants are resumed after bleeding, particularly among patients who initially experienced gastrointestinal bleeding. Systemic thrombosis occurred at a high rate when anticoagulant therapy was withheld after bleeding.

Clinical and angiographic outcomes following percutaneous coronary intervention with sirolimus-eluting stents versus bare-metal stents in hemodialysis patients.

BACKGROUND: Percutaneous coronary intervention for hemodialysis patients has been hampered by the high rate of adverse cardiac events. Our aim was to investigate whether sirolimus-eluting stents (SESs) improve clinical outcomes of hemodialysis patients compared with bare-metal stents (BMSs). STUDY DESIGN: Retrospective study. SETTING & PARTICIPANTS: 123 consecutive patients on hemodialysis therapy treated with either an SES or BMS. There were 56 patients with 68 lesions treated with SESs between August 2004 and April 2006 (SES group) and 67 patients with 71 lesions treated with BMSs 4 years before approval of SESs in Japan (BMS group). PREDICTOR: SES and BMS implantation for hemodialysis patients with coronary artery disease. OUTCOMES & MEASUREMENTS: Follow-up angiography was performed at 6 to 8 months and clinical follow-up was obtained at 9 months after the procedure. Late lumen loss and major adverse cardiac events, including all-cause death, myocardial infarction, and target-lesion revascularization, were investigated. RESULTS: Clinical follow-up was obtained in all patients. Angiographic follow-up was obtained in 50 patients (89.3%) in the SES group and 50 patients (74.6%) in the BMS group. The SES group had more complex lesions than the BMS group. Quantitative angiographic analysis showed a significant difference for in-stent late lumen loss (SES, 0.62 +/- 0.75 mm; BMS, 1.07 +/- 0.75 mm; P = 0.003). Of angiographic restenosis lesions analyzed, a focal restenotic pattern was observed more frequently in the SES group than the BMS group (SES, 87.5%; BMS, 23.8%; P < 0.001). The rate of major adverse cardiac events was significantly lower in the SES group (n = 14; 25.0%) than the BMS group (n = 26; 38.9%; log-rank P = 0.02). LIMITATIONS: Retrospective study design, small sample size, and a single-center study. CONCLUSIONS: Clinical and angiographic data in the present study suggest that SESs are more effective than BMSs in hemodialysis patients.

Efficacy of culprit plaque assessment by 64-slice multidetector computed tomography to predict transient no-reflow phenomenon during percutaneous coronary intervention.

BACKGROUND: It has been reported that multidetector spiral computed tomography (MDCT) allows the classification of coronary plaques by measuring computed tomography (CT) density values. However, the impact of CT density values in culprit lesions on the occurrence of transient no-reflow during percutaneous coronary intervention (PCI) has not been investigated. METHODS: The study population consisted of 51 consecutive patients who were diagnosed as having coronary artery disease by 64-slice MDCT before PCI. The CT density values were measured in multiple cross-sectional images along the plaque by 5-pixel regions of interest at multiple sites in the culprit plaque. The measurements were performed by 2 physicians who were unaware of the outcome of PCI. In addition, we describe a new observation noted on MDCT: from the formal resemblance to a ring, we dubbed these images as showing a "signet ring-like appearance." RESULTS: Of the total 51 patients, 9 had transient no-reflow during the procedure. There was a significant difference in CT density of the culprit plaque between patients with transient no-reflow and those without (67.0 +/- 10.1 vs 97.8 +/- 37.2 Hounsfield units, P = .018). In addition, a signet ring-like appearance was observed more frequently in patients with transient no-reflow (55.6% vs 16.7%, P = .013). By multivariate analysis, low CT density value and ejection fraction were identified as independent predictors of transient no-reflow. CONCLUSIONS: The assessment of plaque characteristics by MDCT might be useful for the prediction of transient no-reflow during PCI.

Evaluation of coronary artery bypass grafts and native coronary arteries using 64-slice multidetector computed tomography.

BACKGROUND: The conventional use of 16-slice multidetector computed tomography (MDCT) remains somewhat limited for evaluating stenoses in vein graft distal anastomotic sites and in coronary arteries. We investigated the diagnostic accuracy of 64-slice MDCT for assessment of both grafts and coronary arteries in patients with coronary artery bypass grafts. METHOD: The study group included 54 consecutive patients. One patient had to be excluded from the study because of arrhythmia. The remaining 53 patients with coronary artery bypass grafts underwent both 64-slice MDCT angiography and invasive coronary angiography. The MDCTs were analyzed for presence of significant stenosis (>50%) or occlusion in grafts and coronary arteries. The results were compared with those of invasive coronary angiography. RESULTS: Overall, 138 of 146 (94.5%) grafts including distal anastomoses were evaluable with MDCT. Evaluability of arterial grafts, venous grafts, distal runoff arteries, and nongrafted arteries was 90.3%, 98.6%, 84.0%, and 97.3%, respectively. After censoring nonevaluable grafts or arteries and considering them to be positive, the sensitivity to detect significant stenosis or occlusion in arterial grafts was 100% and specificity was 91.4%. In venous graft, sensitivity was 100% and specificity was 98.1%. In distal runoff arteries, sensitivity to detect significant stenoses was 83.3% and specificity was 80.2%. In nongrafted arteries, sensitivity was 100% and specificity was 87.5%. CONCLUSIONS: Sixty-four-slice MDCT showed improved ability to assess bypass grafts and coronary arteries. However, there were still difficulties in assessment of distal runoff arteries in which relatively low diagnostic accuracy was observed that might limit clinical implementation of MDCT.

Additive Value of Integrated Backscatter IVUS for Detection of Vulnerable Plaque by Optical Frequency Domain Imaging: An Ex Vivo Autopsy Study of Human Coronary Arteries.

OBJECTIVES: This study sought to evaluate the diagnostic performance of optical frequency domain imaging (OFDI) for recognition of coronary plaque morphologies and to assess additive values of integrated backscatter intravascular ultrasound (IB-IVUS) in detection of vulnerable plaque. BACKGROUND: Precise diagnosis of coronary lesions susceptible to plaque rupture and thrombosis may serve to stratify the risk of future coronary events and to make decisions for appropriate treatment of choice. METHODS: Twenty-seven coronary arteries from 14 human autopsy hearts were interrogated ex vivo by OFDI and IB-IVUS. Imaged segments were sectioned at 3 mm intervals where a total of 360 pairs of cross-sectional images coregistered to histology were investigated. RESULTS: Overall, OFDI could depict various plaque components and structures such as fibrous tissue, sheet and nodular calcification, lipid, cholesterol crystals, and healed plaque rupture. OFDI could detect 14 of 18 thin-cap fibroatheroma (TCFA), however, the diagnostic accuracy was not high (positive predictive value [PPV] = 60.9%, κ = 0.664; area under the curve [AUC]: 0.88) mainly because of signal interference from macrophages. Further, we defined IB-IVUS-derived TCFA by recursive partitioning analysis as: 1) cross-sectional % lipid area >65.1%; 2) % lipid area >32.3 but <65.1% with plaque area >10.5 mm(2), where TCFA detection by IB-IVUS alone was marginal (PPV = 50.0%, κ = 0.545; AUC: 0.82). However, when IB-IVUS was combined with OFDI, all pseudo OFDI-derived TCFA (non-TCFA on histology) were excluded. Accordingly, PPV of TCFAs diagnosed by both OFDI and IB-IVUS was improved to 100.0% (κ = 0.704; AUC: 0.93). CONCLUSIONS: OFDI could recognize detailed morphologies of human coronary plaque. However, diagnostic accuracy of both OFDI alone and IB-IVUS alone to identify TCFA is limited. Combination of IB-IVUS with OFDI improved the accuracy for TCFA detection, suggesting hybrid imaging or further development of novel devices will be required to identify coronary lesions responsible for future events.

The clinical characteristics and prognosis of lesions with in-stent eccentric tissue proliferation and strong signal attenuation detected by optical coherence tomography.

There are still some patients who require repeat revascularization despite of drug-eluting stent (DES) implantation. The present study aimed to investigate the relationship between optical coherence tomography (OCT) findings and recurring target lesion revascularization (TLR) after percutaneous coronary intervention (PCI) for in-stent restenosis (ISR). We reviewed 50 patients (54 coronary lesions) who underwent PCI for ISR, which included 25 DES-ISR lesions. The PCI strategy depended on the interventionalist's discretion, and DES implantation was performed for 38 (70 %) lesions. Tissue characteristics were assessed qualitatively and quantitatively using the frame showing maximal lumen narrowing (minimal lumen area). In qualitative analysis, OCT detected coexistence of eccentric tissue proliferation and strong signal attenuation (ESA). ESA was observed in six lesions (11 %) in five patients (10 %). Hemodialysis (80 vs. 20 %, p = 0.013) and DES-ISR (100 vs. 40 %, p = 0.0069) were significantly more frequent in ESA patients/lesions than in others. One-year follow-up revealed that re-TLR was more frequently performed for ESA lesions (83 vs. 8 %, p = 0.0002). The findings reveal that ESA detected in OCT images of ISR is related to TLR after PCI for DES-ISR especially in patients undergoing maintenance hemodialysis.

Three-dimensional registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation.

Evidence suggests high-resolution, high-contrast, [Formula: see text] intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and three-dimensional (3-D) registration methods to provide validation of IVOCT pullback volumes using microscopic, color, and fluorescent cryo-image volumes with optional registered cryo-histology. A specialized registration method matched IVOCT pullback images acquired in the catheter reference frame to a true 3-D cryo-image volume. Briefly, an 11-parameter registration model including a polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition. Virtual catheter parameters were optimized to maximize cryo and IVOCT lumen overlap. Multiple assessments suggested that the registration error was better than the [Formula: see text] spacing between IVOCT image frames. Tests on a digital synthetic phantom gave a registration error of only [Formula: see text] (signed distance). Visual assessment of randomly presented nearby frames suggested registration accuracy within 1 IVOCT frame interval ([Formula: see text]). This would eliminate potential misinterpretations confronted by the typical histological approaches to validation, with estimated 1-mm errors. The method can be used to create annotated datasets and automated plaque classification methods and can be extended to other intravascular imaging modalities.

3D registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation.

High resolution, 100 frames/sec intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and 3D registration methods, to provide validation of IVOCT pullback volumes using microscopic, brightfield and fluorescent cryo-image volumes, with optional, exactly registered cryo-histology. The innovation was a method to match an IVOCT pull-back images, acquired in the catheter reference frame, to a true 3D cryo-image volume. Briefly, an 11-parameter, polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition. Virtual catheter parameters were optimized to maximize cryo and IVOCT lumen overlap. Local minima were possible, but when we started within reasonable ranges, every one of 24 digital phantom cases converged to a good solution with a registration error of only +1.34±2.65µm (signed distance). Registration was applied to 10 ex-vivo cadaver coronary arteries (LADs), resulting in 10 registered cryo and IVOCT volumes yielding a total of 421 registered 2D-image pairs. Image overlays demonstrated high continuity between vascular and plaque features. Bland-Altman analysis comparing cryo and IVOCT lumen area, showed mean and standard deviation of differences as 0.01±0.43 mm2. DICE coefficients were 0.91±0.04. Finally, visual assessment on 20 representative cases with easily identifiable features suggested registration accuracy within one frame of IVOCT (±200µm), eliminating significant misinterpretations introduced by 1mm errors in the literature. The method will provide 3D data for training of IVOCT plaque algorithms and can be used for validation of other intravascular imaging modalities.

Prevalence of carotid artery stenosis in patients with coronary artery disease in Japanese population.

BACKGROUND AND PURPOSE: Prevalence of carotid artery stenosis in patients with coronary artery disease (CAD) is unknown in Japanese population. METHODS: The study populations consisted of 632 consecutive patients who underwent coronary angiography because of suspicion of CAD. All patients underwent carotid ultrasonography to screen carotid artery stenosis before coronary angiography. We defined echographic carotid stenosis as area stenosis of >50% or peak systolic velocity of >200 cm/s. RESULTS: Echographic carotid stenosis was observed in 124 patients (19.6%). Coronary angiography revealed 433 patients had CAD. Prevalence of echographic carotid artery stenosis was 14 of 199 (7.0%), 18 of 124 (14.5%), 28 of 131 (21.4%), and 64 of 178 (36.0%) in patients with 0-, 1-, 2-, and 3-vessel CAD, respectively (P<0.0001). The prevalence rate with carotid stenosis and CAD was 25.4%. Multivariate stepwise logistic regression analysis showed that age and the extent of CAD were independently related to the presence of carotid stenosis (P=0.0002 and <0.0001, respectively). CONCLUSIONS: Prevalence of carotid stenosis in patients with CAD is high in Japan as well as in Western countries. Screening of carotid artery stenosis is recommended especially in older patients with multivessel CAD.

Volumetric assessment of lesion severity with optical coherence tomography: relationship with fractional flow.

AIMS: Frequency-domain optical coherence tomography (FD-OCT) provides a rapid tomographic scan of a coronary vessel, with an accurate reconstruction of its lumen profile. An FD-OCT-based metric that corresponds more closely with physiological significance of lesions may enable more precise guidance of interventional procedures. The aim of this feasibility study was to evaluate a new method for quantifying coronary lesion severity that estimates hyperaemic flow resistance of branched vessel segments imaged by FD-OCT. METHODS AND RESULTS: An analytical flow model was developed that relates fractional flow reserve (FFR) to the vascular resistance ratio (VRR), a measure of blood flow resistance derived from volumetric FD-OCT lumen profiles. The VRR-FFR relationship was evaluated in 21 patients on whom both pressure measurement and FD-OCT imaging were performed in a random order during maximal hyperaemia. Lesion severity assessed by VRR showed a stronger linear correlation with FFR measurements (before model optimisation [blinded]: r=0.81; p<0.001; root mean square error [RMSE]=0.095 FFR units; after model optimisation [unblinded]: r=0.91; p<0.001; RMSE=0.066 FFR units) than quantitative coronary angiography and FD-OCT-derived measurements of minimum lumen area (r=0.67; p=0.0012) and per cent area stenosis (r=-0.61; p=0.004). CONCLUSIONS: Accurate volumetric measurement of the lumen profile with FD-OCT correlates more closely with FFR than standard metrics derived from single image cross-sections. VRR shows promise as a method for evaluating lesion severity.

Unrestricted utilization of frequency domain optical coherence tomography in coronary interventions.

Frequency domain optical coherence tomography (FD-OCT) has shown promise to evaluate coronary devices in clinical trials, however, little is known about its application in clinical practice. This prospective, single center initiative planned for 100 % FD-OCT utilization in all patients undergoing coronary interventions during a 60-day period. Operators pre-specified the planned intervention based on angiography alone. FD-OCT success was defined as acquisition of good quality images enabling adequate quantification of vessel dimensions and lesion/percutaneous coronary intervention (PCI) assessment. Impact on management occurred when angiography-based planning was altered based on FD-OCT data. There were 297 FD-OCT acquisitions performed in 155 vessels from 150 patients. There were no FD-OCT procedural related cardiac adverse events and success was obtained in 85.7 % of all target vessels (pre-PCI = 76.8 % vs. post-PCI = 90.1 %, p = 0.004). Success on the first pullback occurred in 80.3 % overall (61.9 % in the initial operator experience and 85.5 % after the third procedure). FD-OCT impact on management was 81.8 % pre-PCI and 54.8 % post-PCI. Stent malapposition was detected in 39.2 % (89.4 % underwent further intervention) and edge dissection in 32.5 % (21.1 % treated with stent). FD-OCT success and management impact were similar in ACS and non-ACS patients (82.1 vs. 81.1 %, p = 1.000, and 62.5 vs. 65.1 %, p = 0.854, respectively). FD-OCT is safe, can successfully be incorporated into routine practice, and alters procedural strategy in a high proportion of patients undergoing PCI.

Serial assessment of vessel interactions after drug-eluting stent implantation in unprotected distal left main coronary artery disease using frequency-domain optical coherence tomography.

OBJECTIVES: This study sought to assess stent-vessel interactions after drug-eluting stent (DES) implantation in unprotected left main coronary artery (ULM) by frequency-domain optical coherence tomography (FD-OCT). BACKGROUND: Percutaneous coronary intervention using DES in ULM has been increasingly performed in routine practice. Recently, FD-OCT assessments of DES-vessel interactions have been used as surrogates for DES safety; however, there are no FD-OCT studies in ULM. METHODS: We prospectively enrolled 33 consecutive patients with ULM disease treated with sirolimus- (n = 11) and everolimus-eluting stents (n = 22). FD-OCT assessments were performed post-percutaneous coronary intervention and at 9-month follow-up. Three different segments of ULM were compared: distal (DIS), bifurcation (BIF), and ostial-body (BODY). The primary endpoints were percentages of uncovered and malapposed struts at 9-month follow-up, and the secondary endpoint was neointimal hyperplasia area. RESULTS: We analyzed 25,873 stent struts. Significant differences were demonstrated for percentage of uncovered struts (3.4%, 11.7%, and 18.7%, respectively for DIS, BIF, and BODY; p < 0.05 for all the comparisons). Malapposition was also more common in BODY (5.3%) than in DIS (0.6%) and BIF (2.0%) segments (p < 0.05 for BODY vs. DIS, and BODY vs. BIF). Equivalent neointimal hyperplasia areas were demonstrated in all segments. Acute malapposition rates led to different patterns of DES-vessel interactions at 9-month follow-up. CONCLUSIONS: Distinct patterns of DES-vessel interactions were demonstrated in different segments of ULM. Acute stent strut malapposition affects these findings.