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The article discusses the role of various intravascular imaging techniques in the detection of vulnerable plaque and during drug-eluting stent (DES) implantation. Optical coherence tomography (OCT) uses a light source to reflect small objects including blood cells. Near-infrared (NIR) spectroscopy uses a catheter which contains an optic fiber that emits diffuse reflectance light into the tissue. Meanwhile, angioscopy requires a blood-free field and offers high resolution images of the surface of the plaque.

The article presents a study which assessed 1-month angioscopic and histopathologic sequelae of overlapping paclitaxel eluting stents (PES) in pig coronary arteries. Results showed the visibility of stent struts and mural thrombi in bare-metal stents. In addition, mural thrombi were abundant but distributed irregularly throughout the PES. Adjacent nonstented reference segments demonstrated impaired endothelium-dependent vasoreactivity.

The article presents abstracts of several articles related to colon and rectum diseases. There is an abstract on endoscopic treatment of postoperative colorectal anastomotic strictures. The purpose of this study was to analyze 94 consecutive patients with postoperative colorectal anastomotic stenoses treated endoscopically and identify the potential contributing factors for the development of anastomotic stenosis and restenosis. Another abstract is on perforation during colonoscopy in endoscopic ambulatory surgical centers. This purpose of this retrospective study was to determine the rate of colonoscopic perforation in 45 endoscopic ambulatory surgery centers.

BACKGROUND. Since the literature indicated that in the early stages of primary venous disease valves are simply dilated, some authors performed external valvuloplasty of deep and superficial venous valves with encouraging results, although some failures were observed without being sufficiently explained. OBJECTIVE. To obtain further interpretations of the natural history of venous valve pathology, clarify methods for a correct diagnostic approach, and provide indications for the external valvuloplasty procedure. METHODS. Forty-two proximal valves of the long saphenous vein removed for varicose veins of the lower limbs were studied with optical microscopy. The relationship between histologic alterations and age of varicose disease was investigated. Five valvuloplasties were explanted for recurrent reflux and submitted to histopathological observation. Preoperative echographic findings and histologic observations were compared. Nineteen limbs were subjected to external valvuloplasty under angioscopic control; preoperative echographic findings and angioscopic observations were compared. RESULTS. The histologic alterations observed in venous valves were mainly hypotrophy of cusps, which seemed to be the main cause of failure after external valvuloplasty. The frequency of such hypotrophic alterations increases with the age of varicose disease but no statistically significant relationship was found. Preoperative echographic imaging of venous valves does not appear sufficiently predictive when compared with histologic and angioscopic examinations. CONCLUSION. Hypotrophic valve damage seems to be prevalent in patients with varicose veins of the lower limbs. Valve cusp hypotrophy may be present in early disease though some normal cusps can be found in advanced disease. When preoperative echographic visualization of cusps is doubtful, intraoperative angioscopy plays the main role in the diagnosis of venous valve disease before and during external valvuloplasty. [ABSTRACT FROM AUTHOR]

BACKGROUND. Hemodynamic correction (CHIVA) is a conservative, ambulatory, and controversial varicose vein treatment. It consists of selected ligatures of the superficial venous system, decided by means of preoperative duplex mapping. OBJECTIVE. Prospective evaluation of 80 patients, operated on according to the CHIVA technique described by Claude Franceschi. Mean follow-up length was 30 months. METHODS. Fifty-five consecutive patients were operated on after clinical, ultrasonographic, ambulatory venous pressure and light reflection rheography evaluations. After a 3-year follow-up, another 25 consecutive patients were selected applying sonic exclusion criteria that emerged in the first part of the study. This second series was operated on by means of intraoperative angioscopy. The same preoperative evaluations have been used to study the outcome in all patients. RESULTS. CHIVA failed in the short saphenous vein territory varices and when the long saphenous vein and the insufficient perforating veins had a preoperative diameter greater than 10 and 4 mm, respectively. The procedure showed a long saphenous vein patency of 90.4% and registered a total recurrence rate of 18.7%. CONCLUSIONS. CHIVA seems to be a more effective varicose vein treatment than high ligation and distal stab avulsion. It also preserves a higher rate of long saphenous veins, suitable for bypass surgery. [ABSTRACT FROM AUTHOR]

The article discusses several topics on vascular healing in the process of drug-eluting stents (DES) using angioscopy including on the relationship between angiographic late loss and angioscopic thrombus and another on the in vivo angioscopy performed in a porcine model.

Introduction: The vascular response after second-generation drug-eluting stent (2nd-DES) implantation is reportedly better than that after first-generation DES (1st-DES) placement. However the vascular response after third-generation DES (3rd-DES) remains unclear. Methods: To analyze neointimal quantity and quality 9.3±2.8 months after 1st-DES (sirolimus-eluting stent: SES, n=25; paclitaxel-eluting stent: PES, n=14), 2nd-DES (permanent polymer everolimus-eluting stent: PP-EES, n=43; slow-release zotarolimus-eluting stent: R-ZES, n=33), and 3rd DES (bioresorbable polymer SES: BP-SES, n=19; bioresorbable polymer EES: BP-EES, n=5) implantation using angioscopy.Neointimal coverage grade (CG) was evaluated using a 4-point scale ranging from 0 (no coverage) to 3 (complete coverage). We determined maximum (Max-CG) and minimum (Min-CG) coverage grades and the heterogeneity score (HS: Max-CG minus Min-CG). Yellow grade (YG) at the stented site was assessed using a 4-point grading scale ranging from 0 (white) to 3 (bright yellow). We also assessed thrombus formation. Results: There were no significant differences in Max-CG or HS. Min-CG was significantly greater in 3rd-DES than in 1st or 2nd-DES (3rd-DES vs. 2nd-DES: 1.54±0.71 vs. 0.94±0.47; p<0.01, 3rd-DES vs. 1st-DES: 1.54±0.71 vs. 0.74±0.54; p<0.01, p < 0.01 (ANOVA)). YG was significantly lower in 3rd-DES than in 1st or 2nd-DES (3rd-DES vs. 2nd-DES: 0.54±0.50 vs. 0.98±0.67; p=0.01, 3rd-DES vs. 1st-DES: 0.54±0.50 vs. 1.05±0.64; p<0.01, 2nd-DES vs. 1st-DES: 0.98±0.67 vs. 1.05±0.64; p=0.55, p<0.01(ANOVA)). There was significantly less thrombus formation in 3rd-DES and 2nd-DES than in 1st- DES(p<0.01(ANOVA)). Conclusions: 3rd-DES may be better clinical outcome than 1st-DES or 2nd-DES. [ABSTRACT FROM AUTHOR]

Introduction: Aortic calcification is associated with atherosclerotic risk factors and an increased risk of death and cardiovascular disease. However, the relationships aortic calcification and aortic plaque instability are not yet elucidated. Recently, some reports showed non-obstructive aortic angioscopy seemed to visualize atherosclerotic changes of aortic wall more clearly compared with computed tomography (CT). The purpose of this study was to evaluate whether aortic calcification is associated with aortic vulnerable plaques in patients with cardiovascular disease. Methods: We investigated 51 consecutive patients with confirmed or suspected coronary artery disease who underwent both aortic angioscopy and CT. The AC volume (ACV) was measured using the volume-rendering method by extracting the area >130 HU within the whole aorta. ACV index (ACVI) was defined as ACV divided by the body surface area. We evaluated the number of ruptured plaque (RP), ulceration and fissure by aortic angioscopy in the whole aorta. We excluded 4 hemodialysis patients. All patients were divided into the median value of ACVI. Results: The mean age of patients was 68 ± 10. The median of ACVI was 10.7 ml /m2 [3.9-22.7]. High ACVI patients had significantly greater number of RP, ulceration and atheromatous plaques detected by aortic angioscopy compared with those of low ACVI (2.2 ± 2.7 vs 0.8 ± 1.1, p= 0.033, 1.6 ± 1.2 vs 0.9 ± 1.0, p=0.041, 4.0 ± 3.1 vs 1.9 ± 1.8, p=0.009, respectively). Furthermore, the patients without aortic calcification did not have RP at all. Conclusions: Aortic calcification detected by CT was related to aortic vulnerable plaques in patients with cardiovascular disease. [ABSTRACT FROM AUTHOR]

Introduction: Coronary spasm (CS) has been speculated to affect the coronary vasculature; it is also considered to be a cause of acute coronary syndrome. Additionally, the frequency of patients with vasospastic angina (VSA) developing intracoronary erosion and thrombus has been clarified. Hypothesis: To confirm the relationship between CS and intracoronary erosion and thrombus, we assessed the internal aspects of coronary arteries using coronary angioscopy (CAS) in patients with VSA. Methods: The study included 43 patients with VSA who underwent coronary angiography (CAG), spasm provocation test (SPT), and CAS. In all patients, acetylcholine was infused in the left coronary artery and right coronary artery (RCA). Based on SPT results, the vessels were classified into spastic vessels (SVs) and non-spastic vessels (N-SVs). Furthermore, SVs were divided into the following subgroups: 1) vessels with CS occurrence from the proximal to mid-portion and CAS observability within the spastic segments (SV1s) and 2) vessels with distal CS occurrence and CAS observability only within the non-spastic segments (SV2s). In addition, CS was classified into focal and diffuse types according to the length of CS. CAS was performed in the RCA and left anterior descending coronary artery to determine the presence of erosion and thrombus. Results: We identified 31 patients with SV1 and 12 patients with SV2. Among the 31 patients with SV1, erosion and thrombus were detected in 7 (23%) and 8 (26%), respectively, and total intracoronary abnormalities were observed in 12 (39%). Such intracoronary abnormalities tended to be less frequently observed in patients with taking a calcium-channel blocker (CCB) before the STP (18% vs. 50% in patients without taking a CCB, p = 0.0818). Among the 70 vessels observed using CAS, 34 SV1s, 21 SV2s, and 15 N-SVs were identified. Notably, all abnormal findings were observed in SV1 (35%, p < 0.01), and none were observed in SV2 and N-SV. Furthermore, such abnormalities were more frequently observed at the focal spasm segments than at the diffuse spasm segments of the vessels (31% vs. 9%, p < 0.05). Conclusions: Our results suggest that erosion and thrombus are observed in approximately 40% of patients with VSA. Such intracoronary abnormalities may be partly affected by the CS type. [ABSTRACT FROM AUTHOR]

Introduction: Wall shear stress (WSS) has been considered as a major determinant of aortic atherosclerosis. Recently-developed non-obstructive aortic angioscopy (AAS) can visualize a variety of its atherosclerotic pathology, including plaque rupture within aorta in vivo. This study investigated the relationship between AAS-derived aortic plaque rupture within aortic arch and the stereographic distribution of WSS derived by computational fluid dynamics modeling (CFD) using three dimensional CT angiography (3DCT). Methods: We investigated 23 consecutive patients who underwent both AAS and 3DCT. WSS was measured with an application of CFD based on finite element method using uniform inlet and outlet flow conditions. Aortic plaque rupture (RP) was detected by AAS (Figure). Results: The maximum and mean values of WSS were 63.3±26.2 Pa and 2.4±0.5 Pa. According to AAS, a total of 14 RPs were detected (3 patients at greater curvature of aortic arch and 11 patients at lesser curvature). The patients with a distinct aortic RP provided a significantly-higher value of the maximum WSS within aortic arch compared the patients without (73.3±29.0 Pa vs 50.4±15.2 Pa, p=0.035), whereas there was no significant difference in the mean WSS within aortic arch between them (2.4±0.5 Pa vs 2.3±0.6 Pa, NS). Conclusions: Higher value of the maximum WSS within aortic arch derived by CFD using 3DCT was related to Aortic RP detected by aortic angioscopy. [ABSTRACT FROM AUTHOR]

Introduction: Angioscopy is the only devices that can directly visualize the lumen of blood vessels. However, clinical judgment is not technically straightforward in all operators but requires some experience. This study aims to design two-class classification models by deep machine learning based on angioscopic images in patients with PAD and to visualize the pictures considering prognosis so that even inexperienced operators can receive the benefit. Hypothesis: We hypothesized that the prediction model of deep machine learning could be used for the analysis of angioscopic images to obtain the same accuracy as experienced operators. Methods: 12 consecutive patients with PAD were performed the invasive assessment of vascular physiology. Image data were trained using Keras on TensorFlow which are framework and library of deep machine learning. In the first phase of the study, raw RGB data (640x480 pixels) were input to the neural network, but the accuracy was low, and there was a problem that the models did not converge. However, it was possible to solve it by devising the pretreatment of the data. We finally created a two-class classification model that classifies amputated and non-amputated cases. Results: In the 2-D histogram of the amputated case shows low chromatic color and contains the broad range spectrum in red to magenta as compared to the healed case. By using the trained prediction model in the analysis, it is possible to discriminate the poor prognosis findings at the accuracy of 97.5% which seemed to be the ability almost equal to a skilled operator. Besides, it is especially beneficial for treatment devising because high-risk areas in the entire movie frame can be efficiently visualized. In summary, these results show that the accuracy, loss, sensitivity, specificity, and AUC are 97.5(%), 0.0818, 94.0(%), 92.0(%) and 0.93, respectively. Conclusions: This is the first research to investigate angioscopic images using the predicted model trained by a deep machine learning. Through image analysis using predict model, it is possible that operators with low experience can efficiently obtain judgment with high experience values. The technology that we have designed therefore assists in our understanding of the role of angioscopy in PAD patients. [ABSTRACT FROM AUTHOR]

The article discusses the use of an angioscopic view of a three-dimensional (3D) computed tomographic angiography (CTA) to detect an aneurysm arising from the left sinus of Valsalva in a man who presented with exertional chest pain and a mediastinal mass. It mentions the CTA angioscopic image's confirmation that the aneurysm did not involve the aortic valve or the left coronary ostium. The role of CTA angioscopic images in surgical planning for complex aortic root pathology is cited.

Henoch-Schönlein purpura (HSP) is considered a benign disease of children. We report a severe case of HSP in an adult causing renal failure and gastrointestinal (GI) hemorrhage. Despite aggressive treatment with corticosteroids, cyclophosphamide, and plasmapheresis, the patient developed massive GI bleeding from 2 Dieulafoy lesions and died weeks after bowel resection. Although uncommon, when massive GI hemorrhage occurs, actively bleeding Dieulafoy lesions, although uncommon, should be suspected and evaluated early.

Background: Although coronary angiograms after bare-metal stent (BMS) implantation show late luminal narrowing beyond 4 years, the detailed changes inside the BMS have not yet been fully elucidated., Methods and Results: Serial angiographic and angioscopic examinations were performed immediately (baseline), 6 to 12 months (first follow-up), and >or=4 years (second follow-up) after stenting without target lesion revascularization in 26 segments of 26 patients who received BMS deployment for their native coronary arteries. Angioscopic observation showed atherosclerotic yellow plaque crushed out by stent struts in 22 patients (85%) and mural thrombus in 21 patients (81%) at baseline. At first follow-up, white neointimal hyperplasia was almost completely buried inside the struts, and both yellow plaque and thrombus had decreased in comparison with baseline (12% and 4%, respectively; P<0.001). The frequencies of yellow plaque and thrombus increased from the first to second follow-ups (58% and 31%, respectively; P<0.05). All of the yellow plaques in the second follow-up were located not exterior to the struts but protruding from the vessel wall into the lumen. Late luminal narrowing, defined as an increasing of percent diameter stenosis between the first and second follow-ups, was greater in segments with yellow plaque than in those without yellow plaque (18.4+/-17.3% versus 3.6+/-4.2%, respectively; P=0.011)., Conclusions: This angiographic and angioscopic study suggests that white neointima of the BMS may often change into yellow plaque over an extended period of time, and atherosclerotic progression inside the BMS may contribute to late luminal narrowing.

Background: It recently has been hypothesized that a larger late loss may have a protective role against stent thrombosis. The relationship between angiographic late loss and the presence of thrombus based on angioscopic findings within paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) was investigated in this study., Methods and Results: Prospective 6-month follow-up angiographic and angioscopic examinations were performed on 18 patients for PES and on 20 patients for SES. Late loss was measured by quantitative coronary angiography. Angioscopic neointimal stent coverage (NSC) grade was classified as follows: 0=uncovered struts without neointima, 1=visible struts through thin neointima, and 2=no visible struts. In each patient, maximum NSC, minimum NSC, and the existence of thrombus were evaluated. Late loss and maximum NSC were greater in PES than in SES (0.38+/-0.43 versus 0.10+/-0.23 mm; P=0.02 and P=0.0004, respectively). Late loss was correlated with maximum NSC (grade 0, 0.06+/-0.01 mm; grade 1, 0.10+/-0.05 mm; and grade 2, 0.48+/-0.46 mm), whereas there was no correlation between late loss and minimum NSC. The prevalence of patients with uncovered struts did not differ (44% of PES, 40% of SES; P=0.78). In-stent thrombus was found more frequently in PES than in SES (72% versus 40%, P=0.046) despite no occurrence of stent thrombosis. Only within PES were thrombi found in the segments of NSC grade 2 associated with large late loss., Conclusions: The present study suggests that angiographic large late loss was not associated with a low risk of in-stent thrombus.

Rupture of a vulnerable plaque is the main cause of acute coronary syndromes and myocardial infarction. The features of rupture-prone atherosclerotic plaques have been previously described by pathologists. However, identification of vulnerable plaques in vivo is essential to study their natural history and to evaluate potential treatment modalities. Coronary angiography is the gold standard for the diagnosis of coronary artery disease, but it is unable to distinguish between stable and unstable plaques and to accurately predict future cardiac events. This current perspective describes the recently developed invasive imaging techniques to detect atherosclerotic vulnerable plaques in the coronary tree.

Background: Elevated troponin T levels in non-ST-elevation acute coronary syndromes (NSTE-ACS) have been shown to predict an adverse outcome. Furthermore, it has been reported that troponin T could help improve the effectiveness of such new antithrombotic drugs as platelet GPIIb/IIIa antagonists and low-molecular-weight heparins. We hypothesized that such elevated troponin T levels in NSTE-ACS indicate the presence of thrombus at culprit lesions, and this hypothesis was verified through the use of coronary angioscopy., Methods and Results: We studied 57 consecutive patients with NSTE-ACS who underwent preinterventional angioscopy. Before catheterization, we obtained blood samples to determine troponin positivity, and the patients were then classified as either troponin-positive or troponin-negative groups (diagnostic threshold, 0.1 ng/mL). Using angioscopy at the culprit lesions, we examined the presence of coronary thrombus, yellow plaque, and complex plaque. Moreover, we compared the preinterventional angiographic parameters (thrombus and complexity of the culprit lesion, and TIMI flow) between the two groups. Twenty-two patients were troponin-positive and 35 patients were troponin-negative. Univariate analyses indicated that the TIMI flow and the incidence of coronary thrombus detected with angioscopy correlate with the elevated troponin T levels. A multivariate logistic regression analysis showed the presence of coronary thrombus detected with angioscopy to be the only independent factor associated with elevated troponin T levels in patients with NSTE-ACS (odds ratio, 22.1; 95% CI, 2.59 to 188.42; P=0.0046)., Conclusions: Using angioscopy, the elevated troponin T levels in NSTE-ACS were confirmed to be strongly associated with the presence of coronary thrombus.

Background: The purpose of the present study was to define whether integrated backscatter (IB) combined with conventional intravascular ultrasound (IVUS) makes tissue characterization of coronary arterial plaques possible., Methods and Results: IB-IVUS was performed in coronary arteries (total 18 segments) of 9 patients at autopsy, and the findings were compared with the histology. RF signals, which were digitized at 2 GHz in 8-bit resolution, were obtained with an IVUS system with a 40-MHz catheter. IB values of the RF signal from the region of interest (ROI) (100-microm depth, 1.4 degrees per line) were calculated by use of a personal computer. IB values on the ROIs were divided into 5 categories, compared with each of the plaque histologies: category 1 (thrombus), -88 < IB < or = -80; category 2 (intimal hyperplasia or lipid core), -73 < IB < or = -63; category 3 (fibrous tissue), -63 < IB < or = -55; category 4 (mixed lesions), -55 < IB < or = -30; and category 5 (calcification), -30 < IB < or = -23. On the basis of these categories, we analyzed 5120 ROIs per segment in each ring-like arterial specimen. Color-coded maps of plaques were constructed by use of these IB data and conventional IVUS data, which reflected the plaque histology of autopsied coronary arteries well. Then, the same method was undertaken in 24 segments with plaque from 12 patients in vivo with angina pectoris. Comparisons between coronary angioscopy and IB-IVUS revealed that the surface color of plaques in angioscopy reflected the thickness of the fibrous cap rather than the size of the lipid core., Conclusions: IB-IVUS represents a new and useful tool for evaluating the tissue structure of human coronary arterial plaques.

The study of atherosclerotic disease during its natural history and after therapeutic intervention will enhance our understanding of disease progression and regression and aid in selecting appropriate treatments. Several invasive and noninvasive imaging techniques are available to assess atherosclerotic vessels. Most of the standard techniques identify luminal diameter, stenosis, wall thickness, and plaque volume; however, none can characterize plaque composition and therefore identify the high-risk plaques. We will present the different imaging modalities that have been used for the direct assessment of the carotid, aortic, and coronary atherosclerotic plaques. We will review in detail the use of high-resolution, multicontrast magnetic resonance for the noninvasive imaging of vulnerable plaques and the characterization of plaques in terms of their various components (ie, lipid, fibrous, calcium, or thrombus).

Background: Coronary angioscopy has been reported to be superior to angiography and intravascular ultrasound for detecting intracoronary thrombus. However, in-vivo histopathologic validation of angioscopic detection of intracoronary thrombus had not been performed., Objective: To perform histopathologic validation of in-vivo angioscopic detection of coronary thrombus., Design: An experimental, blinded comparison of angioscopy and histopathology., Methods: Coronary angioscopy was performed from 0 to 14 days after angioplasty in 39 porcine coronary arteries. When thrombus was detected by angioscopy, it was subclassified into white, mixed red-white, or red thrombus according to color. By histopathology the presence of thrombus was determined and subclassified into platelet-rich, mixed platelet-erythrocyte, or erythrocyte-rich thrombus., Results: Angioscopy correctly classified 19 of 21 coronary thrombi (sensitivity 90%) but incorrectly classified nine of 18 arteries without formation of thrombus as having a thrombus (specificity 50%). Positive and negative predictive values were 68 and 82%, respectively. The angioscopic subclassification of thrombus into white, mixed red-white, or red thrombi was not correlated to the corresponding histopathologic morphology (platelet-rich, mixed platelet-erythrocyte, or erythrocyte-rich) of the observed thrombi (chi2 test: P = 0.5)., Conclusions: Angioscopic detection of thrombus in vivo had high sensitivity and negative predictive value but low-to-moderate specificity and positive predictive value. Visual assessment of color of angioscopically detected thrombi seemed not to reflect histopathologic morphology of thrombus according to the definitions used in the present study.

Background: Limited angioscopic information is available on the natural history of infarct-related plaque after myocardial infarction (MI), in particular the effect of thrombolysis., Methods and Results: We studied with angioscopy the morphological characteristics of the infarct-related lesion in 56 patients between 24 hours and 4 weeks after MI. Forty of these patients were initially treated with a thrombolytic agent. Most lesions were complex (complex + ulcerated shape = 54%). The predominant color of the plaque was yellow in 79% of cases; only 6% were uniformly white. Angioscopically visible thrombus was found in 77% of cases. Despite angioscopic evidence of instability, only 7% of the patients had post-MI angina. During the 1-month time window since the occurrence of MI, there was no significant difference in the angioscopic appearance of the plaque except for a slight increase in uniformly white plaques (P=.07). The use of a thrombolytic agent at the onset of MI was associated with a reduction in thrombus size and less protruding thrombi (P=.02) but not with a decreased frequency of plaque containing thrombi. Furthermore, a trend for more frequently ulcerated plaques (45% versus 16%, P=.06) was associated with the use of a thrombolytic agent., Conclusions: These results suggest that healing of the infarct-related lesion requires more than 1 month and that an "unstable" yellow plaque with adherent thrombus is common during that period. This finding may partly explain the unique behavior of recent infarct-related lesions, which are more prone to occlude than other lesions.

Background: Angioscopy surpasses other diagnostic tools, such as angiography and intravascular ultrasound, in detecting arterial thrombus. This capability arises in part from the unique ability of angioscopy to assess true color during imaging. In practice, hardware-induced chromatic distortions and the subjectivity of human color perception substantially limit the theoretic potential of angioscopic color. We used a novel application of tristimulus colorimetry to quantify thrombus color to both aid in its detection and assess its composition., Methods and Results: A series of human thrombus models were constructed in vitro. Spatial homogeneity was ensured by light and electron microscopy. Quantitative colorimetric angioscopic analysis demonstrated excellent measurement reproducibility (mean difference, 0.07% to 0.17%), unaffected by illuminating light intensity (coefficient of variation, 0.21% to 3.67%). Colorimetric parameters C1 and C2 were strongly correlated (r=.99, P<.0001) with thrombus erythrocyte concentration. Principal components analysis transformed these parameters into a single value, the thrombus erythrocyte index, with little (0.06%) loss of content. Measured and predicted concentrations were similar (mean difference, 0.16 erythrocytes per 1 ng). Randomly ordered images were also subjected to visual analysis by three experienced angioscopists, with suboptimal levels of both intraobserver (mean kappa=0.63) and interobserver (mean kappa=0.48) agreement. In addition, visual ranking resulted in a Kendall rank coefficient of 0.72 to 0.76 versus a perfect 1.00 from quantitative measurement., Conclusions: Quantitative colorimetric angioscopic analysis provides a new, objective, and reproducible analytic tool for assessing angioscopic images of human thrombus. Even under ideal circumstances, experienced angioscopists do a poor job of assessing color (and therefore composition) of human thrombi. This technique can, for the first time, provide quantitative information of thrombus composition during routine diagnostic imaging.

Purpose: To develop an animal model of complement-induced retinal vasculopathy and determine whether it resembles Purtscher's retinopathy., Methods: Intravenous cobra venom factor was used to achieve intravascular activation of the complement system in cats. After a single bolus of cobra venom factor (75 units/kg), retinal blood flow was monitored at regular intervals by fluorescein angioscopy and angiography., Results: Multiple small retinal arteriolar occlusions were present during the initial fluorescein transit of the immediate postinjection fluorescein study in 12 of 12 animals. Small, rapidly moving gaps in the fluorescein column were seen in two thirds of the animals observed continuously by fluorescein angioscopy. Angiographically, the obstructions were transient, and filling of the associated patches of capillary nonperfusion occurred within 3 minutes. Purtscher's-like ischemic retinal infarcts did not develop in any eye. Histopathologic analysis failed to demonstrate the nature of the transient vascular obstructive lesions, but indirect evidence suggested the possibility of granulocyte aggregates., Conclusion: Intravascular activation of the complement system produces transient microembolic retinal arteriolar occlusions in the cat. Although this model may represent a mild form of Purtscher's retinopathy, factors in addition to complement activation appear necessary to induce ischemic retinal infarcts.

An optimized, contrast-enhanced 3D MR angiography sequence is combined with image postprocessing to render interior views of the pulmonary arteries. Virtual angioscopy was successfully demonstrated on both a healthy volunteer and a pulmonary embolism patient. By targeting selected pulmonary artery branches, virtual angioscopy has the potential to become a powerful adjunct to the use of reformatted sections and maximum intensity projections in the assessment of pulmonary embolism.

Background: Clinical and angiographic criteria have a limited ability to predict adverse outcome in patients with unstable angina who are undergoing percutaneous transluminal coronary angioplasty (PTCA). We investigated whether the use of angioscopy can improve prediction of early adverse outcome after PTCA., Methods and Results: Angioscopic characterization of the culprit lesion was performed before PTCA in 32 patients with unstable angina and 10 with non-Q-wave infarction. Seven patients (17%) had an adverse outcome (myocardial infarction, repeat PTCA, or need for coronary artery bypass graft surgery) within 24 hours after PTCA. Six of 18 patients with a yellow culprit lesion had an adverse outcome compared with 1 of 24 in whom the culprit lesion was white (P = .03). Six of 20 patients with plaque disruption suffered an adverse outcome compared with 1 of 22 with nondisrupted plaques (P = .04). Six of 17 patients with intraluminal thrombus had an adverse outcome, whereas only 1 of 25 patients without thrombus suffered an adverse outcome (P = .01). Yellow color, disruption, and thrombus at the culprit lesion site were associated with an eightfold increase in risk of adverse outcome after PTCA. The prediction of PTCA outcome based on characteristics of the plaque that were identifiable by angioscopy was superior to that estimated by the use of angiographic variables., Conclusions: In patients with unstable angina and non-Q-wave infarction, angioscopic features of disruption, yellow color, or thrombus at the culprit lesion site can identify patients at high risk of early adverse outcome after PTCA. Angioscopy was superior to angiography for prediction of PTCA outcome.

Background: The presence of angiographically identified intracoronary thrombus has been variably associated with complications after coronary angioplasty. Angiography has been shown to be less sensitive than angioscopy for detecting subtle details of intracoronary morphology, such as intracoronary thrombi. The clinical importance of thrombi detectable by angioscopy but not by angiography is not known., Methods and Results: Percutaneous coronary angioscopy was performed in 122 patients undergoing conventional coronary balloon angioplasty (PTCA) at six medical centers. Unstable angina was present in 95 patients (78%) and stable angina in 27 (22%). Therapy was not guided by angioscopic findings, and no patient received thrombolytic therapy as an adjunct to angioplasty. Coronary thrombi were identified in 74 target lesions (61%) by angioscopy versus only 24 (20%) by angiography. A major in-hospital complication (death, myocardial infarction, or emergency bypass surgery) occurred in 10 of 74 patients (14%) with angioscopic intracoronary thrombus, compared with only 1 of 48 patients (2%) without thrombi (P = .03). In-hospital recurrent ischemia (recurrent angina, repeat PTCA, or abrupt occlusion) occurred in 19 of 74 patients (26%) with angioscopic intracoronary thrombi versus only 5 of 48 (10%) without thrombi (P = .03). Relative risk analysis demonstrated that angioscopic thrombus was strongly associated with adverse outcomes (either a major complication or a recurrent ischemic event) after PTCA (relative risk, 3.11; 95% CI, 1.28 to 7.60; P = .01) and that angiographic thrombi were not associated with these complications (relative risk, 0.85; 95% CI, 0.36 to 2.00; P = .91)., Conclusions: The presence of intracoronary thrombus associated with coronary stenoses is significantly underestimated by angiography. Angioscopic intracoronary thrombi, the majority of which were not detected by angiography, are associated with an increased incidence of adverse outcomes after coronary angioplasty.

Background: Discordant results have been reported regarding morphological predictors of restenosis after percutaneous transluminal coronary angioplasty (PTCA). These discrepancies may be related to the limitations of angiography in the study of plaque morphology., Methods and Results: We studied 117 consecutive patients who underwent successful PTCA and who underwent coronary angioscopy before and immediately after the procedure. Angiographic follow-up was performed in 99 (85%) patients. We analyzed the relationship between angioscopic variables at the time of PTCA and the occurrence of restenosis assessed by quantitative coronary angiography. Plaque shape and color had no effect on late loss in luminal diameter (late loss: smooth lesions, 0.55 +/- 0.68 mm; complex lesions, 0.76 +/- 0.60 mm; white plaques, 0.51 +/- 0.56 mm; yellow plaques, 0.65 +/- 0.72 mm; P = NS). An angioscopic protruding thrombus at the PTCA site was associated with significantly greater loss in luminal diameter (late loss: no thrombus, 0.47 +/- 0.54 mm; lining thrombus, 0.59 +/- 0.67 mm; protruding thrombus, 1.07 +/- 0.77 mm; P < .05). Dissection assessed by angioscopy immediately after PTCA had no effect on late loss in luminal diameter (late loss: no dissection, 0.60 +/- 0.60 mm; simple dissection, 0.82 +/- 0.75 mm; complex dissection, 0.57 +/- 0.80 mm; P = NS)., Conclusions: These results show that coronary angioscopy may be helpful in predicting the risk of restenosis after PTCA. The high rate of angiographic recurrence observed when PTCA is performed at thrombus-containing lesions supports a role for thrombus in the process of luminal renarrowing after PTCA.

Background: Patients with diabetes mellitus have a higher prevalence of atherosclerotic heart disease and a higher incidence of myocardial infarction than the general population. Diabetic patients also have several hematologic, rheologic, and metabolic abnormalities not present in their nondiabetic counterparts that may predispose them to atherosclerotic plaque rupture and intraluminal thrombosis and consequently may lead to the formation of morphologically complex plaques and the development of acute coronary syndromes., Methods and Results: Percutaneous coronary angioscopy was performed in 55 consecutive patients with unstable angina. We observed plaque color, texture, and the incidence of intracoronary thrombus associated with the culprit lesions of these patients. The population consisted of 17 (31%) diabetic and 38 (69%) nondiabetic patients. The presence of coronary risk factors was not significantly different between the two populations. Ulcerated plaque was found in 16 of 17 (94%) diabetic patients versus 23 of 38 (60%) nondiabetic patients (P = .01). Intracoronary thrombi were seen in 16 of 17 (94%) diabetic patients versus 21 of 38 (55%) nondiabetic patients (P = .004)., Conclusions: The results of the angioscopic examination show that diabetic patients with unstable angina have a higher incidence of plaque ulceration and intracoronary thrombus formation than nondiabetic patients. This increased frequency of complex lesion morphology is consistent with the disproportionately higher risk for development of acute coronary syndromes in these patients.

Background: Postmortem-derived findings support the common beliefs that lipid-rich coronary plaques with a thin, fibrous cap are prone to rupture and that rupture and superimposed thrombosis are the primary mechanisms causing acute coronary syndromes. In vivo imaging with intracoronary techniques may disclose differences in the characterization of atherosclerotic plaques in patients with stable or unstable angina and thus may provide clues to which plaques may rupture and whether rupture and thrombosis are active., Methods and Results: We assessed the characteristics of the ischemia-related lesions with coronary angiography and intracoronary angioscopy and determined their compositions with intracoronary ultrasound in 44 patients with unstable and 23 patients with stable angina. The angiographic images were classified as noncomplex (smooth borders) or complex (irregular borders, multiple lesions, thrombus). Angioscopic images were classified as either stable (smooth surface) or thrombotic (red thrombus). The ultrasound characteristics of the lesion were classified as poorly echo-reflective, highly echo-reflective with shadowing, or highly echo-reflective without shadowing. There was a poor correlation between clinical status and angiographic findings. An angiographic complex lesion (n = 33) was concordant with unstable angina in 55% (24 of 44); a noncomplex lesion (n = 34) was concordant with stable angina in 61% (14 of 23). There was a good correlation between clinical status and angioscopic findings. An angioscopic thrombotic lesion (n = 34) was concordant with unstable angina in 68% (30 of 44); a stable lesion (n = 33) was concordant with stable angina in 83% (19 of 23). The ultrasound-obtained composition of the plaque was similar in patients with unstable and stable angina., Conclusions: Angiography discriminates poorly between lesions in stable and unstable angina. Angioscopy demonstrated that plaque rupture and thrombosis were present in 17% of stable angina and 68% of unstable angina patients. Currently available ultrasound technology does not discriminate stable from unstable plaques.

The optimal management for traumatic arterial intimal injuries is unresolved. Three therapeutic options were compared in an experimental model employing a standard intimal flap created in 51 canine superficial femoral arteries. Group 1 (14 arteries) underwent resection with end-to-end repair. Group 2 (19 arteries) received acetylsalicylic acid (ASA) and observation only. Group 3 (21 arteries) underwent endovascular excision of the flap with angioscopic guidance. Control intimal flaps (18 arteries) were created and observed without further intervention. Patency in group 1 (primary repair) and group 2 (ASA) was 100%; the patency in both was significantly (p < 0.05) greater than in the controls, which was 67%. Patency in group 3 (endovascular excision) was 79%. Residual luminal defects were observed in only 8% of the arteries repaired primarily, but in 76% of the aspirin-treated arteries. Residual luminal defects following endovascular excision were present in 53% of the arteries remaining patent. Although resection and primary repair (group 1) provided better results than observation alone (control), addition of ASA (group 2) also sustained patency. However, a high incidence of residual intimal defects occurred, the natural history of which is unknown. While endovascular excision (group 3) may become a feasible alternative, current technology provided inferior patency with frequent residual intimal defects. These results suggest that observation alone supplemented with antiplatelet medication (ASA) may be adequate treatment, but longer follow-up is necessary for confirmation.