Impact of 12-Month Angioscopic Thrombi and Yellow Plaque After Drug-Eluting Stent Implantation.

BACKGROUND: Coronary angioscopy (CAS) has 2 unique abilities: direct visualization of thrombi and plaque color. However, in the recent drug-eluting stent (DES) era, serial CAS findings after DES implantation have not been fully elucidated. We investigated the impact of CAS findings after implantation of a polymer-free biolimus A9-coated stent (PF-BCS) or durable polymer everolimus-eluting stent (DP-EES).Methods and Results: We investigated serial CAS and optical coherence tomography (OCT) findings at 1 and 12 months in 99 patients who underwent PF-BCS or DP-EES implantation. We evaluated factors correlated with angioscopic thrombi and yellow plaque, and the clinical impact of both thrombi and yellow plaque at 12 months (BTY). The BTY group included 17 (22%) patients. The incidence and grade of thrombi and yellow plaque decreased from 1 to 12 months. Although no patients had newly appearing thrombi at 12 months, 2 DP-EES patients had newly appearing yellow plaque at 12 months. Multivariable analysis revealed HbA1c, minimum stent area, and adequate strut coverage were significant factors correlated with 12-month angioscopic thrombi, and DP-EESs were significantly correlated with 12-month yellow plaque. However, BTY was not correlated with clinical events. CONCLUSIONS: The management of diabetes, stent area, and adequate stent coverage are important for intrastent thrombogenicity and polymer-free stents are useful for stabilizing plaque vulnerability.

Coronary arterial repair in patients with stable angina pectoris or acute coronary syndrome after ultrathin biodegradable polymer sirolimus-eluting stent implantation at 1-year follow-up by coronary angioscopy.

BACKGROUND: Imaging modality-based evidence is limited that compares the extent of coronary arterial repair after percutaneous coronary intervention between patients with stable angina pectoris (SAP) and those with acute coronary syndrome (ACS). METHODS: Between December 2018 and November 2021, a single-center, nonrandomized, observational study was conducted in 92 patients with SAP (n = 42) or ACS (n = 50), who were implanted with Orsiro sirolimus-eluting stent (O-SES) providing a hybrid (active and passive) coating and underwent 1-year follow-up by coronary angioscopy (CAS) after implantation. CAS assessed neointimal coverage (NIC), maximum yellow plaque (YP), and mural thrombus (MT). RESULTS: Baseline clinical characteristics were comparable between the SAP and ACS groups. The follow-up periods were comparable between the two groups (390.1 ± 69.9 vs. 390.6 ± 65.7 days, p = 0.99). The incidences of MT at 1 year after implantation were comparable between the two groups (11.4% vs. 11.1%, p = 0.92). The proportions of "Grade 1" in dominant NIC grades were highest in both groups, and the proportions of maximum YP grades and MT were comparable between the two groups. CONCLUSION: O-SES-induced coronary arterial repair at the site of stent implantation, irrespective of the types of coronary artery disease.

Angioscopic Comparison of Early- and Mid-Term Vascular Responses Following Treatment of ST-Elevation Acute Myocardial Infarction With Biodegradable vs. Durable Polymer Everolimus-Eluting Stents　- A Prespecified Subanalysis of the MECHANISM AMI RCT.

BACKGROUND: The vessel healing process after implantation of biodegradable polymer (BP) and durable polymer (DP) everolimus-eluting stent (EES) in ST-elevation myocardial infarction (STEMI) lesions remains unclear.Methods and Results: We conducted a multicenter prospective randomized controlled trial to compare early (2 weeks) and mid-term (12 months) vascular responses after implantation of BP-EES vs. DP-EES in STEMI patients. In this prespecified subanalysis, serial coronary angioscopy (CAS) analysis was performed in 15 stents in the BP-EES arm (n=10 patients) and 14 stents in the DP-EES arm (n=10 patients). At the 2-week follow-up, there was no significant difference in the estimated marginal means of the neointimal coverage grade (primary endpoint) between the 2 arms (mean [±SE] 0.00±0.00 in both arms; P>0.999). There were no significant differences between the BP-EES and DP-EES groups in the yellow color grade (1.046±0.106 vs. 0.844±0.114, respectively; P=0.201) or the presence of thrombus (77.8% vs. 88.8%, respectively; P=0.205). At 12 months, competent strut coverage, defined as yellow color grade ≤1, no thrombus, and a neointimal coverage grade ≥1 was achieved more frequently in the BP-EES than DP-EES arm (85.2% vs. 53.1%; adjusted odds ratio 2.11 [95% confidence interval 1.26-3.53]; P=0.023). CONCLUSIONS: Neointimal coverage 2 weeks after implantation of BP-EES and DP-EES in STEMI lesions was comparable on CAS evaluation. However, at 1 year, BP-EES was independently associated with competent strut coverage.

Comparison of 1-Month and 12-Month Vessel Responses Between the Polymer-Free Biolimus A9-Coated Stent and the Durable Polymer Everolimus-Eluting Stent.

BACKGROUND: A polymer-free biolimus A9-coated stent (PF-BCS) may achieve better arterial healing than a durable polymer drug-eluting stent owing to its polymer-free feature.Methods and Results: This multicenter, prospective, observational study enrolled 105 patients (132 lesions) who underwent PF-BCS (51 patients, 71 lesions) or durable polymer everolimus-eluting stent (DP-EES, 54 patients, 61 lesions) implantation. Serial coronary angioscopy (CAS) and optical coherence tomography (OCT) examinations were performed at 1 and 12 months, and the serial vessel responses were compared between PF-BCS and DP-EES. The primary outcome measure was the incidence of subclinical intrastent thrombus on CAS. The secondary outcome measures were: adequate strut coverage (≥40 µm) on OCT and maximum yellow color grade on CAS. The incidence of thrombus was high at 1 month (100% vs. 93%, P=0.091), but decreased at 12 months (18% vs. 25%, P=0.56), without a significant difference between PF-BCS and DP-EES. The adequate strut coverage rate was significantly higher (84±14% vs. 69±22%, P<0.001) and yellow color was significantly less intense (P=0.012) at 12 months in PF-BCS than in DP-EES; however, they were not significantly different at 1 month (adequate strut coverage: 47±21% vs. 50±17%, P=0.40; yellow color: P=0.99). CONCLUSIONS: Although the thrombogenicity of PF-BCS was similar to that of DP-EES, the adequate coverage and plaque stabilization rates of PF-BCS were superior to those of DP-EES at 12 months.

Clinical significance of microvessels detected by in vivo optical coherence tomography within human atherosclerotic coronary arterial intima: a study with multimodality intravascular imagings.

The significance of microvessels within atherosclerotic plaques is not yet fully clarified. Associated with plaque vulnerability. The aim of this study is to examine tissue characteristics of plaque with microvessels detected by optical coherence tomography (OCT) by use of a commercially available color-coded intravascular ultrasound (IVUS) and coronary angioscopy (CAS). The subjects examined comprised of 44 patients with stable angina pectoris who underwent percutaneous coronary intervention. Microvessels were defined as a tiny tubule with a diameter of 50-300 µm detected over three or more frames in OCT. We compared the total volume of microvessels with tissue component such as fibrotic, lipidic, necrotic, and calcified volume and the number of yellow plaque. In IVUS analysis, % necrotic volume and % lipidic volume were significantly correlated and % fibrotic volume was inversely significantly correlated with the total volume of microvessel (r = 0.485, p = 0.0009; r = 0.401, p = 0.007; r = - 0.432, p = 0.003, respectively). The number of plaque with an angioscopic yellow grade of two or more was significantly correlated with the total volume of microvessel (r = 0.461, p = 0.002). The greater the luminal volume of microvessels, the more the percent content of necrotic/lipidic tissue volume within plaque and the more the number of yellow plaques. These data suggested that microvessels within coronary plaque might be related to plaque vulnerability.

Impact of diabetes mellitus on the early-phase arterial healing after drug-eluting stent implantation.

BACKGROUND: Early arterial healing after drug-eluting stent (DES) implantation may enable short dual-antiplatelet therapy (DAPT) strategy. The impact of diabetes mellitus (DM) on this healing has not been elucidated. We used coronary angioscopy (CAS) to compare intravascular status of DM and non-DM patients in the early phase after DES implantation. METHODS: This study was a multicenter retrospective observational study. We analyzed CAS findings of 337 lesions from 270 patients evaluated 3-5 months after DES implantation. We divided the lesion into two groups: DM (n = 149) and non-DM (n = 188). We assessed neointimal coverage (NIC) grades (dominant, maximum and minimum), thrombus adhesion and maximum yellow color grade. NIC was graded as follows: grade 0, stent struts were not covered; grade 1, stent struts were covered by thin layer; grade 2, stent struts were buried under neointima. Yellow color was graded as grade 0, white; grade 1, light yellow; grade 2, yellow; grade 3, intensive yellow. RESULTS: Minimum NIC grade was significantly lower in DM than in non-DM groups (p = 0.002), whereas dominant and maximum NIC grades were similar between them (p = 0.59 and p = 0.94, respectively), as were thrombus adhesion (44.3% vs. 38.8%, p = 0.32) and maximum yellow color grade (p = 0.78). A multivariate analysis demonstrated that DM was an independent predictor of minimum NIC of grade 0 (odds ratio: 2.14, 95% confidence interval: 1.19-3.86, p = 0.011). CONCLUSIONS: DM patients showed more uncovered struts than non-DM patients 3-5 months after DES implantation, suggesting that the recent ultra-short DAPT strategy might not be easily applied to DM patients.

In Vivo Evaluation of Tissue Protrusion by Using Optical Coherence Tomography and Coronary Angioscopy Immediately After Stent Implantation.

BACKGROUND: The relationship between the characteristics of tissue protrusion detected by using optical coherence tomography (OCT) and the findings of coronary angioscopy (CAS) immediately after stent implantation were evaluated.Methods and Results:A total of 186 patients (192 stents) underwent OCT before and after stenting and were observed by using CAS immediately after stenting and at the chronic phase. Patients were assigned to irregular protrusion, smooth protrusion, and disrupted fibrous tissue protrusion groups according to OCT findings. Serum high-sensitivity C-reactive protein (hs-CRP) levels were measured before and after stent implantation. The grade of yellow color (YC) and neointimal coverage (NC), and incidence of thrombus in the stented segment were evaluated by using CAS. After stent implantation, maximum YC grade (smooth, 0.64±0.80; disrupted fibrous tissue, 0.50±0.77; irregular, 1.50±1.09; P<0.0001), a prevalence of Max-YC grade of 2 or 3 (smooth, 17%; disrupted fibrous tissue, 17%; irregular, 50%; P<0.0001) and thrombus (smooth, 15%; disrupted fibrous tissue, 10%; irregular, 69%; P=0.0005), and elevated hs-CRP levels (smooth, 0.22±0.89; disrupted fibrous tissue, -0.05±0.29; irregular, 0.75±1.41; P=0.023) were significantly higher in irregular protrusion than in the other 2 groups. In the chronic phase, maximum- and minimum-NC grade and heterogeneity index, and thrombus did not differ significantly among the 3 groups. CONCLUSIONS: Irregular protrusion was associated with atherosclerotic yellow plaque, incidence of thrombus, and vascular inflammation. The angioscopic findings in the chronic phase may endorse the clinical efficacy of second- and third-drug eluting stents, regardless of the tissue protrusion type.

Impact of Neointimal Condition and Platelet Reactivity on Intrastent Thrombus at Long-Term Follow-up After 2nd- and 3rd-Generation Drug-Eluting Stent Implantation　- Insights From a Coronary Angioscopy and Pharmacodynamic Study.

BACKGROUND: Although the incidence of very late stent failure (VLSF) is reduced with newer generation drug-eluting stent (DES), the mechanism of VLSF has not been fully explored.Methods and Results:This study evaluated both local vascular healing using coronary angioscopy and systemic factors determined by platelet reactivity at long-term follow-up after 2nd- and 3rd-generation DES implantation in patients with acute coronary syndrome. Coronary angioscopy was performed to assess neointimal coverage (NIC), yellow color (YC) grade and presence of thrombus. The obtained findings were compared with 2nd- and 3rd-DES. Platelet aggregation was assessed by light transmittance aggregometry. 100 consecutive patients were prospectively enrolled: 2nd- (n=50) and 3rd-DES (n=50). 3rd-DES patients had significantly higher NIC grade and lower YC grade compared with 2nd-DES. The presence of thrombus was tended to be lower with 3rd-DES than with 2nd-DES (8% vs. 18%, P=0.11). Patients with thrombus had significantly higher maximum platelet aggregation and higher prevalence of high on-treatment platelet reactivity (HPR) than those without thrombus. Multivariable analysis showed stent strut exposure and HPR as independent predictors of thrombus. CONCLUSIONS: Newer generation DES contribute to better vascular healing depending on the degree of neointimal coverage. In addition to local factors at the stented lesion, systemic factors such as degree of platelet reactivity might also contribute to VLSF.

Different vascular healing process between bioabsorbable polymer-coated everolimus-eluting stents versus bioresorbable vascular scaffolds via optical coherence tomography and coronary angioscopy (the ENHANCE study: ENdothelial Healing Assessment with Novel Coronary tEchnology).

Recent clinical trials have raised concerns about the safety and efficacy of ABSORB™ bioresorbable vascular scaffolds (BVS). The difference in the vascular healing process between SYNERGY™ bioabsorbable polymer-coated everolimus-eluting stents (BP-EES) and BVS remains unclear. The aim of the ENHANCE study was to compare vascular healing on BP-EES versus BVS by optical coherence tomography (OCT) and coronary angioscopy (CAS) at 4- and 12-month follow-ups. This is a prospective, non-randomized, single center clinical trial. Thirteen eligible patients with multivessel disease were enrolled. BP-EES and BVS were simultaneously implanted in the same patients, but in different coronary vessels. Imaging follow-up with both OCT and CAS was completed in 11 patients at 12 months. Neointimal coverage rates were similar between the two groups based on OCT measurements. The neointimal thickness of BP-EES was significantly thicker at the 12th month than at the 4th month, whereas the neointimal thickness of BVS did not change between the measurements taken at the 4th and 12th month. Existence of intra-stent thrombus was significantly higher in the BVS group, compared to the BP-EES group. On the other hand, CAS revealed that red-thrombi and yellow-plaque were more frequently observed in BVS at 4 months and up to 12-month follow-ups than in BP-EES. These findings suggested that the evidence of instability remained up to 12 months in the vascular healing with BVS, compared to that with BP-EES. Vascular healing of the stented wall was recognized at the very early phase after BP-EES implantation. However, vascular healing with BVS was still incomplete after 12 months.

Effect of drug-coated balloon angioplasty on in-stent restenotic coronary lesions analyzed with optical coherence tomography and serial coronary artery angioscopy.

Drug-coated balloon angioplasty (DCBA) has been recognized for its utility in preventing in-stent re-restenosis (ISR); however, imaging of the neointima immediately after treatment and during follow-up has only been described in a few case reports. This study aimed to determine the efficacy and mechanism of the DCBA using imaging studies both immediately after the DCBA and during the follow-up period. We enrolled 15 consecutive patients who underwent DCBA for in-stent restenosis (ISR). The in-stent neointimal volume was evaluated using optical coherence tomography (OCT), and the in-stent yellow grade was assessed using coronary angioscopy (CAS) immediately after DCBA and during the median follow-up period of 9 (8-15) months. The neointimal volume was significantly reduced from 77.1 ± 36.2 mm3 at baseline to 60.2 ± 23.9 mm3 immediately after DCBA (p = 0.0012 vs. baseline) and to 46.7 ± 21.9 mm3 during the follow-up (p = 0.0002 vs. post DCBA). The yellow grade of the residual plaques at the ISR lesion, which indicated plaque vulnerability, was significantly decreased in the follow-up CAG (from baseline: 1.79 ± 1.03, during the follow-up: 0.76 ± 0.82; p < 0.0001). These data suggest that DCBA may inhibit neointimal formation and provide angioscopic intimal stabilization for ISR lesions.

Atherosclerotic Component of the Yellow Segment After Drug-Eluting Stent Implantation on Coronary Angioscopy　- An Ex-Vivo Validation Study.

BACKGROUND: Coronary angioscopy (CAS) is used to comprehensively evaluate vascular responses after drug-eluting stent (DES) implantation. This study sought to evaluate the capability of CAS for evaluating DES strut coverage grade and color grade of the intima compared with histological images in coronary autopsy specimens. Methods and Results: A total of 23 DES extracted from 11 autopsy hearts were imaged by CAS. All stent segments were graded as white or yellow according to the luminal surface color, and thrombus was evaluated according to a previous report. Neointimal coverage over the DES was graded as 0 (stent struts fully visible) to grade 3 (stent struts fully embedded and invisible). Of 76 segments, neointimal coverage was graded as 0 in 35 (46%), 1 in 22 (29%), 2 in 8 (11%), and 3 in 11 (14%). The neointimal thickness increased significantly with increasing neointimal coverage grade on angioscopy. Neointimal color was graded as white in 40 (53%) and yellow in 36 segments (47%). Histological analysis revealed that yellow neointima contained fibroatheroma, foam cells accumulation or superficial calcium deposition. A thrombus was identified in 13 segments. Thrombi adherent around the stent strut were partly intimal erythrocyte accumulation around the strut. CONCLUSIONS: In-stent yellow segment had atherosclerotic components. CAS could evaluate vascular status comprehensively after DES implantation.

Assessment of Second- and Third-Generation Drug-Eluting Stents on Chronic Coronary Angioscopy　- Multicenter Study on Intra-Coronary AngioScopy After Stent (MICASA) Prospective Data Analysis.

BACKGROUND: The vascular response, in terms of quality and quantity, of the second- and third-generation drug-eluting stents (2G- and 3G-DES, respectively) was assessed prospectively on coronary angioscopy (CAS).Methods and Results:The Multicenter study on Intra-Coronary AngioScopy After Stent (MICASA) is a multicenter CAS registry. A total of 107 DES (71 2G- and 36 3G-DES) were prospectively observed on CAS 8.7±2.7 months after percutaneous coronary intervention. Neointimal coverage (NC) grade was evaluated using a 4-point grading scale, from 0 (no coverage) to 3 (complete coverage). Plaque yellow color (YC) was also assessed using a 4-point grading system, from 0 (white) to 3 (bright yellow). Max-NC (2G-DES vs. 3G-DES: 2.14±0.68 vs. 2.44±0.73, P=0.023); min-NC (1.07±0.48 vs. 1.39±0.60, P=0.002), and dominant-NC (1.57±0.69 vs. 2.08±0.84, P=0.002) were significantly higher and the YC grade (1.23±0.82 vs. 0.86±0.76, P=0.031) significantly lower in the 3G-DES group than in the 2G-DES group. There was no significant difference in the presence of thrombus (28.2% vs. 22.2%, P=0.51) between the 2G- and 3G-DES groups. CONCLUSIONS: The higher NC grade and lower YC grade in 3G-DES than in 2G-DES might be associated with better long-term clinical outcome, which remains to be determined in future studies.

Comparison of the performance of zotarolimus- and everolimus-eluting stents by optical coherence tomography and coronary angioscopy.

Overall stent performance should be characterized by geometric luminal gain acquisition, neointimal coverage of the stent struts, and stabilization of the underlying inflammatory neoatheroma. The aim of this study was to compare the performance of zotarolimus-eluting stent (ZES), everolimus-eluting stent (EES) and bare metal stent (BMS) using optical coherence tomography (OCT) and coronary angioscopy. For 36 stented coronary lesions (BMS, 12 lesions; ZES, 11 lesions; EES, 13 lesions) in 27 patients, we calculated neointimal area and uncovered stent strut rate based on OCT findings at 10 months after stent placement. The grades of neointimal coverage and yellow color, both of which were classified from 0 to 3, were also assessed by coronary angioscopy. The plaque area of the ZES lesions was larger than that of the EES lesions (P < 0.05) but smaller than that of the BMS lesions (P < 0.05). The OCT-based uncovered rate of the ZES lesions was less than that of the EES lesions (P < 0.01), but similar to that of the BMS lesions. The stent coverage grade by angioscopy was higher in the ZES lesions than in the EES lesions (P < 0.05), but similar to the BMS lesions. The yellow grade was less in the ZES lesions than in the EES lesions (P < 0.01), but similar to the BMS lesions. ZES might be better than BMS in terms of neointimal thickening, and better than EES in terms of neointimal coverage as well as prevention of neoatheroma formation. ZES may have superior performance compared with EES.

Identification of post-procedural optical coherence tomography findings associated with the 1-year vascular response evaluated by coronary angioscopy.

Optical coherence tomography (OCT) provides higher resolution intravascular imaging and allows detailed evaluations of stent implantation sites post-percutaneous coronary intervention (PCI). Coronary angioscopy (CAS) can evaluate the vascular response after drug-eluting stent (DES) implantation. The post-PCI OCT findings that are associated with the CAS 1-year vascular response have not been known. We enrolled 168 lesions from 119 patients who underwent OCT-guided PCI using DES and follow-up CAS observation at 1 ± 0.5 year from August 2012 to December 2019. Outcome measures were sufficient neointimal coverage (NIC) defined as stent struts embedded in the neointima, subclinical intrastent thrombus, and vulnerable stented segments defined as those with angioscopic yellow or intensive yellow color 1 year after PCI. We identified the post-PCI OCT findings associated with these CAS findings. Sufficient NIC, subclinical intrastent thrombus, and vulnerable stented segment were detected in 85 lesions (51%), 47 lesions (28%), and 54 lesions (32%), respectively. A multivariate analysis demonstrated that malapposed struts were negatively associated with sufficient NIC (odds ratio 0.87; 95% CI 0.76-0.99; p = 0.029). However, no specific OCT findings immediately after PCI were associated with subclinical intrastent thrombus or vulnerable stented segment. Malapposition immediately after PCI was negatively associated with sufficient NIC at 1 year even without associations between post-PCI OCT findings and subclinical intrastent thrombus or vulnerable stented segment.

Hepatic steatosis evidenced by computed tomography in patients undergoing primary percutaneous coronary intervention for acute myocardial infarction.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) and acute myocardial infarction (AMI) have common pathological links. This study investigates the prognostic impact of NAFLD assessed as hepatic steatosis (HS) by computed tomography (CT) in AMI patients and explores the mechanistic role of NAFLD in cardiovascular (CV) events using coronary angioscopy (CAS). METHODS: We retrospectively examined 342 AMI patients who underwent CT followed by primary percutaneous coronary intervention (PCI) between January 2014 and December 2019. HS was defined as a hepatic to spleen attenuation ratio of <1.0 on CT scans. Major cardiac events (MCE) included cardiac death, non-fatal myocardial infarction, target-vessel revascularization, and target-lesion revascularization. RESULTS: HS was identified in 88 patients (26 %). Patients with HS were significantly younger, had a higher body mass index, and higher hemoglobin A1c, triglyceride, and malondialdehyde low-density lipoprotein levels (all p < 0.05). MCE occurred more frequently [27 (30.7 %) vs. 39 (15.4 %), p = 0.001] in the HS group than in the non-HS group. In the multivariate analysis, the presence of HS was an independent predictor of MCE after adjusting for metabolic risk factor and liver function markers. Among the 74 patients who underwent CAS for a median of 15 days after primary PCI, 51 (69 %) had intrastent thrombus, which was strongly associated with the presence of HS [18 (35 %) vs. 1 (4 %), p = 0.005]. CONCLUSIONS: AMI patients with NAFLD detected by CT often had CAS-derived intrastent thrombi and were at a high risk for CV events. Therefore, these patients should be carefully monitored.

Very Late Stent Thrombosis Due to Neoatherosclerosis After Implantation of an Ultra-Thin Strut Stent.

A 69-year-old man developed very late stent thrombosis (VLST) 3 years after Orsiro stent implantation in the proximal left anterior descending coronary artery. Intravascular imaging evaluations before and after the onset of VLST allowed us to document neoatherosclerosis as the etiology of VLST.

Consensus document on the standard of coronary angioscopy examination and assessment from the Japanese Association of Cardiovascular Intervention and Therapeutics.

Coronary angioscopy (CAS) is a unique diagnostic device that allows direct visualization of the vascular luminal surface in living patients. CAS contributes to elucidate the pathology of coronary artery disease. This consensus document provides a standard for CAS examination and assessment.

Low-molecular-weight dextran-induced anaphylactic shock immediately after intracoronary imaging.

Dextran has been frequently used during intracoronary imaging, such as in optical coherence tomography, optical frequent domain imaging, and coronary angioscopy. We report a case of dextran-induced anaphylaxis in a 70-year-old male with chronic coronary disease. Upon admission, we performed coronary angiography and coronary angioscopy on the patient. After the intracoronary imaging, the patient's blood pressure suddenly fell to 50 mmHg and a rash appeared on his chest. The patient was diagnosed as having dextran-induced anaphylactic shock. Epinephrine was administered repeatedly, and his blood pressure gradually recovered after administering a total of 6 mg epinephrine. There was no recurrence of the anaphylactic shock, and the patient was discharged 12 days later. The incidence of dextran-induced anaphylactic reactions is extremely low; however, they can be fatal. The possibility of anaphylactic shock induced by dextran should be kept in mind by all cardiovascular interventionalists performing intracoronary imaging. Learning objective: Dextran has been frequently used during intracoronary imaging. We report on a case of dextran-induced anaphylaxis in a 70-year-old male with chronic coronary disease. While the incidence of dextran-induced anaphylactic reactions is extremely low, it can lead to fatal events. The possibility of anaphylactic shock induced by dextran should be kept in mind by all cardiovascular interventionalists while performing intracoronary imaging.

Quantitative Validation of the Coronary Angioscopic Yellow Plaque with Lipid Core Burden Index Assessed by Intracoronary Near-Infrared Spectroscopy.

AIM: We aimed to validate the subjective and qualitative angioscopic findings by the objective and quantitative near-infrared spectroscopic (NIRS) assessment to compensate each other's drawbacks. METHODS: This is a single-center prospective observational study. Patients undergoing a planned follow-up coronary angiography after percutaneous coronary intervention were prospectively enrolled from January 2018 to April 2019. The major three vessels were examined by NIRS-intravascular ultrasound, followed by coronary angioscopic evaluation. Yellow color grade on angioscopy was classified into four grades (0, white; 1, slight yellow; 2, yellow; and 3, intensive yellow) at a location of maximal lipid core burden index over 4 mm [LCBI (4)] on NIRS in each vessel. RESULTS: A total of 95 lesions in 44 patients (72.6±6.7 years, 75% male) were analyzed. LCBI (4) was significantly different among different yellow color grades by coronary angioscopy (ANOVA, p＜0.001). Positive correlation was found between angioscopic yellow color grade and LCBI (4) (beta coefficient 164.8, 95% confidence interval 122.9-206.7; p＜0.001). The best cutoff value of LCBI (4) to predict the presence of yellow plaque (yellow color grade ≥ 2) was 448 (sensitivity 79.3%, specificity 69.7%, C-statistic 0.800, 95% confidence interval 0.713-0.887, p＜0.001). CONCLUSION: The qualitative angioscopic assessment was objectively validated by the quantitative NIRS evaluation, which would be helpful for the reinterpretation of the existing evidences of both imaging modalities.

A Parametric Study of Flushing Conditions for Improvement of Angioscopy Visibility.

During an angioscopy operation, a transparent liquid called dextran is sprayed out from a catheter to flush the blood away from the space between the camera and target. Medical doctors usually inject dextran at a constant flow rate. However, they often cannot obtain clear angioscopy visibility because the flushing out of the blood is insufficient. Good flushing conditions producing clear angioscopy visibility will increase the rate of success of angioscopy operations. This study aimed to determine a way to improve the clarity for angioscopy under different values for the parameters of the injection waveform, endoscope position, and catheter angle. We also determined the effect of a stepwise waveform for injecting the dextran only during systole while synchronizing the waveform to the cardiac cycle. To evaluate the visibility of the blood-vessel walls, we performed a computational fluid dynamics (CFD) simulation and calculated the visible area ratio (VAR), representing the ratio of the visible wall area to the total area of the wall at each point in time. Additionally, the normalized integration of the VAR called the area ratio (ARVAR) represents the ratio of the visible wall area as a function of the dextran injection period. The results demonstrate that the ARVAR with a stepped waveform, bottom endoscope, and three-degree-angle catheter results in the highest visibility, around 25 times larger than that under the control conditions: a constant waveform, a center endoscope, and 0 degrees. This set of conditions can improve angioscopy visibility.