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At least 397 records · Page 22Linked to original sources
PubMed1996

A comparison of quality control methods applied to carotid endarterectomy.

OBJECTIVES: To compare the ability of continuous wave Doppler (CWD), B-mode ultrasound (BMU), angioscopy and transcranial Doppler (TCD) to detect technical error during carotid endarterectomy (CEA). DESIGN: A prospective, comparative study in 100 consecutive patients. SETTING: Leicester Royal Infirmary, Leicester, U.K. MATERIALS: Intraoperative TCD monitoring was performed using a SciMed PcDop 842 2 MHz TCD. An Olympus 2.8mm flexible angioscope was used to inspect the arterial lumen prior to restoration of bloodflow. After restoration of flow 10Mhz BMU images and 8Mhz CWD velocity spectra of carotid artery blood flow were obtained. CHIEF OUTCOME MEASURES: The detection of intimal flaps, thrombus, stenoses or other errors of surgical technique likely to result in perioperative morbidity. MAIN RESULTS: CWD and BMU images were technically inadequate in 9% and 24% of cases respectively and neither technique altered clinical management. Angioscopy demonstrated significant technical errors in 12 cases (four intimal flaps, thrombus in eight). TCD detected shunt malfunction in 13% of patients, emboli during dissection in 23% and early postoperative carotid artery thrombosis in three patients. CONCLUSIONS: A combination of TCD monitoring and completion angioscopy provided the maximum yield in terms of diagnosing technical error and establishing the cause of perioperative morbidity.

Angioscopy↗
PubMed1999

A policy of quality control assessment helps to reduce the risk of intraoperative stroke during carotid endarterectomy.

OBJECTIVES: A pilot study in our unit suggested that a combination of transcranial Doppler (TCD) plus completion angioscopy reduced incidence of intra-operative stroke (i.e. patients recovering from anaesthesia with a new deficit) during carotid endarterectomy (CEA). The aim of the current study was to see whether routine implementation of this policy was both feasible and associated with a continued reduction in the rate of intraoperative stroke (IOS). MATERIALS AND METHODS: Prospective study in 252 consecutive patients undergoing carotid endarterectomy between March 1995 and December 1996. RESULTS: Continuous TCD monitoring was possible in 229 patients (91%), while 238 patients (94%) underwent angioscopic examination. Overall, angioscopy identified an intimal flap requiring correction in six patients (2.5%), whilst intraluminal thrombus was removed in a further six patients (2.5%). No patient in this series recovered from anaesthesia with an IOS, but the rate of postoperative stroke was 2.8%. CONCLUSIONS: Our policy of TCD plus angioscopy has continued to contribute towards a sustained reduction in the risk of IOS following CEA, but requires access to reliable equipment and technical support. However, a policy of intraoperative quality control assessment may not necessarily alter the rate of postoperative stroke.

Aged↗
PubMed1995

Relation of coronary angioscopic findings at coronary angioplasty to angiographic restenosis.

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.

Aged↗
PubMed1996

Angioscopic predictors of early adverse outcome after coronary angioplasty in patients with unstable angina and non-Q-wave myocardial infarction.

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.

Adult↗
PubMed2000

[Invasive examination of cardiovascular disease].

Invasive cardiovascular examination by coronary angioscopy and by using a Doppler guide wire, a pressure guide wire and intravascular ultrasound has extensively developed. A Doppler guide wire is used for measurement of flow velocity and evaluation of coronary blood flow. Previous studies demonstrated by assessing maximum coronary vasodilatory capacity that endothelium-dependent or independent vasodilation was impaired in hypertension and hypercholesterolemia or in syndrome X. Elevation of coronary vascular resistance during coronary microvascular spasm has been verified by using a Doppler wire. A pressure guide wire provides coronary transstenotic pressure and is available in calculating myocardial fractional flow reserve(FFRmyo). FFRmyo is an important parameter to assess the coronary functional stenosis that is culprit for myocardial ischemia. It is calculated from the ratio of the mean transstenotic pressure to the mean pressure proximal to the stenosis during maximum coronary hyperemia. The value of FFRmyo considered as necessary for coronary intervention is below 0.75. Intravascular ultrasound(IVUS) is applied as both a diagnostic tool and for intervention purpose. It enabled tissue characterization of the vascular wall as well as measurements of vascular diameter, vascular lumen area and plaque area. It also aided in optimal devise selection, decision of interventional endpoint and assessment of restenosis. IVUS promoted deployment of high-pressure stents to obtain a large post-procedural lumen area as well as abolition of anticoagulation in case of optimal stent deployment. Coronary angioscopy has been developed to investigate the pathogenesis of acute coronary syndrome, where disrupted yellow plaque and overlying thrombus play important roles. Angioscopy has also evidenced regression of intimal hyperplasia after coronary stenting.

Angioscopy↗
PubMed2002

[Coronary thrombosis imaging in humans].

The identification of coronary thrombosis in humans has important prognostic and therapeutic implications. Its recognition calls for invasive techniques: angioscopy, coronarography, and endocoronary ultrasound. Angioscopy allows visualisation of the arterial surface and the detection of thrombus with great sensitivity. Its presence is exclusive to the acute coronary syndromes: 67% in unstable angina, and 75% in myocardial infarction, although it is only present in 27% of cases of stable angina. The relative complexity of its use has led to the abandonment of this technique. Coronarography allows an indirect approach to coronary thrombosis. Certain aspects are evocative such as: intraluminal filling defect, complete occlusion with upstream convexity, ulceration and eccentric type 2 Ambrose classification plaques. As a function of the clinical presentation, the coronarographic views allow a good specificity for the diagnosis of thrombus. The sensitivity is weak, however, compared to angioscopy. Endocoronary ultrasound does not allow identification of fresh thrombus which is not echogenic and does not allow differentiation between older thrombus and lipid plaque. In the future, magnetic resonance imaging could prove interesting in the detection of recent thrombus.

Angioscopy↗
PubMed2005

Three episodes of inferior acute myocardial infarction due to thrombotic occlusion of the right coronary artery: a case report.

A 77-year-old female with two previous inferior myocardial infarctions was transferred to our medical center with a third inferior acute myocardial infarction. Coronary angiography revealed 99% stenosis with rich thrombus in the distal right coronary artery [Thrombolysis in Myocardial Infarction (TIMI) grade 2 flow]. The angiographic appearance of the right coronary artery was similar to the two previous myocardial infarctions. Coronary aspiration was performed and TIMI grade 3 flow was established. To confirm the presence of thrombus, intravascular ultrasound (IVUS) and coronary angioscopy were performed at pre-discharge. IVUS showed a thrombus-like low-density area at the mid right coronary artery. Red thrombi were observed in the same area using coronary angioscopy. Although warfarin had been prescribed for secondary prevention since the first acute myocardial infarction, both the second and third acute myocardial infarction occurred after cessation of warfarin. Patients with acute myocardial infarction due to thrombotic occlusion, confirmed by IVUS or angioscopy, might be good candidates for permanent warfarin therapy.

Aged↗
PubMed2006

[Acute coronary syndrome diagnosed by the intravascular imaging].

Coronary plaque rupture and the following formed thrombus have been revealed the cause of acute coronary syndrome. This evidence had been proposed by the pathologists 100 years ago; however, the intravascular imaging such as intravascular ultrasound (IVUS) or coronary angioscopy has revealed the clinical evidences in live human being. Thrombus and yellow plaque detected by coronary angioscopy as well as the ruptured fibrous cap detected by IVUS are the characteristics for the lesion of ACS, which does not show the significant stenosis. Thus, ACS lesion should be diagnosed by IVUS or coronary angioscopy.

Angina, Unstable↗
PubMed1993

[Effects of ultrasound energy on femoral artery occlusion. Angiographic and angioscopic results].

Ultrasonic energy has been shown to be able to disrupt atherosclerotic plaques and thrombi. The authors used an ultrasonic angioplastic technique developed by the group in 10 patients with a femoral arterial occlusion. The ultrasonic angioplasty was attempted before surgical bypass using a 130 cm long titanium guide wire with a 0.8 mm diameter and a round distal tip measuring 2 or 2.5 mm. Angiographic and angioscopic examinations were performed before and after the procedure in 9 patients. It was not possible to perform the angioplasty in 1 patient. Angioscopy showed that the proximal part of the occlusion consisted of atheromatous material in 3 cases and of thrombus in 6 cases. Angiography showed complete restoration of flow in 4 cases; distal flow was very slow in 4 cases and no distal run-off was observed in 1 case. Angioscopy showed residual stenosis at the site of entry in only 1 case. In 3 cases, the artery had no significant residual stenosis. In the other 5 patients residual stenosis was present and angioscopy showed persistence of strands of fibrin and small thrombi. These results show that ultrasonic angioplasty was capable of recanalising an occlusion in 9 out of 10 patients with partial or total disruption of thrombi. At the present stage of development of this system, balloon angioplasty would be an essential complement in most cases in order to obtain normal flow without significant residual stenosis. The manoeuverability of the guide wire and the relatively small size of the round distal tip explain why not all the thrombi could be treated.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

[Angioscopic evaluation of atherosclerosis].

Recently, percutaneous transluminal angioscopy has been clinically used. We describe the evaluation of atherosclerosis by angioscopy. In observation of aortic and peripheral arteries, color of the luminal surface is yellow in the lesion without endothelial fibrosis, whereas, it is white with endothelial fibrosis. A variety of findings such as endothelial flap, endothelial thickening, mural bleeding, mural or occlusive thrombi are observed in the atherosclerotic lesions. It is difficult to detect these findings by angiography. In observation of coronary arteries, color of the luminal surface is yellow or white and often associates spiral folds in the early stage of atherosclerosis. Plaques are classified to two categories. One is the complex plaque characterised by endothelial flap, rupture of atheroma, ulceration, mural thrombus and usually observed in patients with unstable angina or myocardial infarction. Another is the regular plaque without those findings and observed in patients with stable angina. Angioscopy is useful for evaluation of atherosclerosis.

Angioscopes↗
PubMed1985

Angioscopic visualization of blood vessel interior in animals and humans.

The purpose of this study is to describe the use of angioscopes in flowing bloodstreams of animals and humans, to demonstrate the ability to precisely deliver laser energy to an intravascular target using visual guidance and to determine the information content and spatial content of angioscopy. Angioscopy was performed in 5 living dogs, 16 cadaver vascular segments, and 14 patients at the time of peripheral or coronary bypass surgery. Five canine femoral artery segments received angioscopically directed intravascular Nd:YAG laser irradiation. We were able to precisely direct the laser irradiation to predetermined intimal targets. Gross tissue injury varied from none to carbonization and vascular perforation, depending on incident energy. Using a variety of flexible fiberoptic endoscopes ranging in diameter from 1.5 to 3.7 mm, we were able to visualize intravascular structures including plaque, suture lines, venous valves, and thrombi in living patients. No patient incurred complications of any sort. We conclude that angioscopy using flexible endoscopes can be performed safely, can provide clinically useful information, and may provide a means for delivering visually directed intravascular laser irradiation.

Animals↗
PubMed2005

Visualization of the internal carotid artery using MRA images.

A virtual angioscopy system is implemented to visualize the inside of the internal carotid artery (ICA) for qualitative assessment of carotid artery stenosis using magnetic resonance angiography (MRA) images. The carotid artery is one of the body regions not accessible by real optical endoscopy but can be visualized with virtual endoscopy. In order to visualize the carotid artery, it is segmented using the region-growing algorithm after locating the initial seed on the presegmented binary image. The ICA is separated from the external carotid artery (ECA) using a priori knowledge of the anatomic structure after bifurcation. A fly-through path is computed based on the medial axis transform (MAT) to automatically move the virtual camera from the common carotid artery (CCA) to the ICA. Considering interactive rendering speed and usability of standard graphic hardware, the surface-rendering algorithm with the perspective projection method is used to generate an endoscopic view of the ICA. In addition, the endoscopic view with the raycasting algorithm is provided for off-line navigation of the carotid artery. Virtual angioscopy is highly recommended as a diagnostic tool for identifying the specific location of the stenosis and for analyzing the stenosis qualitatively. The virtual angioscopy system for carotid artery will benefit radiological diagnostics, medical education, surgical planning and postoperative assessment.

Adult↗
PubMed1996

Results of a policy with arm veins used as the first alternative to an unavailable ipsilateral greater saphenous vein for infrainguinal bypass.

PURPOSE: Aggressive policies for distal bypass and coronary revascularization increase the need to identify alternatives to autologous saphenous vein grafts. We examined the performance of arm vein as the primary alternative to contralateral saphenous vein when the ipsilateral saphenous vein was not available. METHODS: A total of 250 arm vein grafts were studied retrospectively in 224 patients (143 men, 81 women, 82.6% with diabetes, mean age 68.3 years) from February 1989 to April 1994. Intraoperative angioscopy was carried out to observe valve lysis, remove abnormalities, and select optimal vein segments. RESULTS: A total of 85 primary, 103 repeat, and 62 graft revision procedures were done for limb salvage in 99.2% of the patients. A total of 41 femoropopliteal, 114 femorotibial-pedal, 33 popliteodistal, and 62 jump or interposition grafts were constructed. A total of 199 grafts were single vein, and 51 were composite vein. The source was cephalic vein alone in 50.4%, cephalic and basilic vein in 35.6%, and basilic vein only in 14%. The contralateral saphenous vein as an alternative conduit was available in 97 (38.8%) instances. Interventions guided by angioscopy to "upgrade" the graft were necessary in 51.6%. Overall early patency (< or = 30 days) was 94.8% (n = 13 occlusions). The cumulative primary patency rate at 1 year was 70.6%, the secondary patency rate was 76.9%, and the limb salvage rate was 88.2%. The 3-year patency rate (limb salvage) was 51.9% (92.4%) for primary grafts, 56.7% (67.1%) in revision grafts, and 42.4% (79.9%) in repeat grafts. In 22.7% (22 of 97) the available contralateral saphenous vein was used for distal revascularization within the follow-up period. CONCLUSIONS: Arm veins are an easily accessible autologous conduit of sufficient length to reach the midtibial level. Excellent patency rates allow durable limb salvage in otherwise difficult circumstances. Vein configuration and splicing do not affect patency rates, but vein quality and repeat operations do. Angioscopy is a valuable adjunct to upgrade graft quality. The contralateral saphenous should be saved for subsequent contralateral revascularization or coronary artery bypass grafting.

Adult↗
PubMed1992

Angioscopic evaluation of coronary-artery thrombi in acute coronary syndromes.

BACKGROUND: Disruption of an atherosclerotic plaque in a coronary artery followed by the formation of a thrombus is believed to be the cause of both unstable angina and acute myocardial infarction. Although thrombolytic therapy is efficacious in patients with acute myocardial infarction, for unknown reasons it is far less effective in patients with unstable angina. We postulated that there might be differences in the composition of the coronary-artery thrombi in unstable angina and acute myocardial infarction. METHODS: To investigate the appearance of coronary-artery thrombi, we performed percutaneous transluminal coronary angioscopy in 15 patients with unstable angina and 16 with acute myocardial infarction. Angioscopy was performed within 48 hours after an episode of pain at rest in the patients with unstable angina and within 8 hours of onset in those with acute myocardial infarction. RESULTS: Angioscopy revealed coronary thrombi in all but two patients (one in each group). Of the 29 patients with thrombi, those with unstable angina were frequently observed to have grayish-white thrombi (10 of 14, 71 percent), but none were seen in the 15 patients with acute myocardial infarction (P less than 0.01). By contrast, reddish thrombi were observed in all 15 patients with acute myocardial infarction who had thrombi, but in only 4 of the 14 patients with unstable angina and thrombi (P less than 0.01). As assessed by coronary angiography, occlusive thrombi occurred frequently in patients with acute myocardial infarction (13 of 16 patients) but were not seen in any of the 15 patients with unstable angina (P less than 0.01). CONCLUSIONS: Coronary-artery thrombi play an important part in the pathogenesis of unstable angina and acute myocardial infarction. However, the appearance of the thrombi is different in the two conditions, possibly reflecting differences in the composition of age of the thrombi or the presence or absence of blood flow in the artery. This difference may account for the contrasting results of thrombolytic therapy.

Angina Pectoris↗
PubMed1987

Comparative trial of Hexabrix (320 mg iodine/ml), iohexol (300 mg iodine/ml) and iopamiron (300 mg iodine/ml) in cerebral and spinal angiography: a preliminary report.

A comparison has been carried out of results of cerebral and spinal-cord angiography with two non-ionic contrast media, iohexol and Iopamiron, and a low-osmolality contrast medium, Hexabrix. A comparative study of iohexol, Hexabrix, and Iopamiron was carried out in a first group of 41 patients, and Hexabrix was compared with Iopamiron in a second group of 56. Evaluation criteria included local and general safety, as well as quality of angioscopy and angiography. In the first group of patients there were no significant differences in safety between the three agents. On the other hand, quality of visualisation during angioscopy with Hexabrix was clearly better. In the second group, safety and quality of the radiographic images were identical; however, once again, quality of angioscopy was better with Hexabrix than with Iopamiron. We conclude that Hexabrix appears to be the best opacifying agent currently available for cerebral and spinal-cord angiography. While results with Iopamiron were quite similar, the latter agent is slightly more expensive.

Cerebral Angiography↗
PubMedDate not supplied

[Erythrocyte aggregation in vivo and diabetic microangiopathy. Physiopathologic determinants and clinical correlations].

Conjunctival angioscopy is a non invasive way for visualization and quantitative evaluation of the microcirculation. Grading red blood cell aggregation is possible in vivo using Ditzel's four grades score. The two-dimensional organization of conjunctival microvessels allows morphometric quantification of microvascular density. The aim of our study was to evaluate the determinant factors of erythrocyte aggregation and the place of conjunctival angioscopy in the early detection of diabetic microangiopathy. Conjunctival parameters were red blood cell aggregation (Ditzel's score) and morphometric evaluation of capillary, venular and arteriolar density. Criteria of diabetic microangiopathy were microalbuminuria and retinal fluorescein angiogram. Both conjunctival angioscopy and retinal angiogram were scored independently. Results obtained in 30 type 1 diabetic patients, with multifactorial statistical analysis, show that red blood cell aggregation in vivo is an essential discriminant factor for diabetic retinopathy and nephropathy. This rheological phenomenon depends more on duration of diabetes (analysis of variance p = .0005, r = .65) and metabolic control than on albuminemia or fibrinogenemia such as in non-diabetic patients. Manual morphometric data confirmed vascular rarefaction associated with excessive red blood cell aggregation (beta = .50). These results suggest that grading red blood cell aggregation in vivo is an interesting tool for physiopathological and clinical studies of diabetic microangiopathy.

Analysis of Variance↗
PubMed1990

[Value of arterioscopy in the prevention of renal artery stenosis after transplantation].

Renal artery stenosis is frequent after transplantation. The systematic pre-operative search for arterial injuries by angioscopy allows a reduction in their incidence. The authors report a series of 60 transplantations with pre-operative angioscopy, which revealed benign injuries and two major injuries which were successfully treated surgically. This prevention allows a reduction in the incidence of stenosis from 12 to 6.6% according to a previous series of 210 transplantations without angioscopy.

Endoscopy↗
PubMed1993

[Technique for endoscopic vein preparation in infra-inguinal in situ bypass].

In situ saphenous vein bypass for infrainguinal reconstructions achieves excellent results, especially for distal anastomoses. The achilles heel of the method is the complete and atraumatic disruption of the valves and the location of significant tributaries of the saphenous vein. An intraoperative quality control is necessary to mend early patency rates. Several control instruments are described: intraoperative arteriography, duplex- or Doppler sonography and angioscopy. We describe the technique of a semiclosed angioscopy guided technique with a novel flushing valvulotome. We use an angiofiberscope with 2.2 or 1.4 mm outer diameter, being introduced through the proximal exposed end of the saphenous vein. Through the distal end or a side branch a modified Mill's valvulotome with a flushing channel (flexible or non flexible) is moved upwards to the angioscope. Every valve cusp is incised under direct vision in a retrograd direction. Simultaneously relevant tributaries are angioscopically located and ligated through small skin incisions. To use the potential of angioscopy we have developed the occluder valvulotome, making endoluminal embolization of tributaries of the saphenous vein possible. Details of these techniques are described.

Angioscopes↗