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Angioscopic versus angiographic detection of thrombus during coronary interventional procedures.

The purpose of this study was to compare angiography and angioscopy for the detection of thrombus during coronary interventional procedures. The diagnosis of coronary thrombus has important clinical implications. Angioscopy can directly visualize the coronary luminal surface and may be more accurate than angiography in the diagnosis of thrombus. Angiography and angioscopy were sequentially performed in 75 patients undergoing a variety of interventional cardiology procedures during 117 distinct procedural time points. The angiographic presence of thrombus was defined as a noncalcified filling defect outlined on at least 3 sides by contrast media. The angioscopic presence of thrombus was defined as red material protruding into the lumen (intraluminal thrombus) or adherent to the luminal wall (mural thrombus) that persisted despite flushing. Thrombus was detected on 14 occasions (12.0%) by angiography compared with 48 (41.0%) by angioscopy (p < 0.05). In 4 of the 14 episodes (28.6%) of angiographic filling defects, angioscopy found no evidence of thrombus and provided an alternative explanation for the angiographic filling defect. When angioscopy was used as a reference standard, the sensitivity of thrombus detection by angiography was 20.8%, with a specificity of 94.2% and a predictive value of 71.4%. The sensitivity of angiography for the detection of intraluminal (protruding into the lumen) thrombus was 100% compared with only 10% for mural (adherent to the luminal wall) thrombus (p < 0.05). Angioscopy was significantly more accurate than angiography for detecting coronary thrombus and may be considered an improved reference standard for this diagnosis.

Aged↗

New angioscopic findings in graft failure after infrainguinal bypass.

We have previously shown that intraoperative angioscopy is a safe, useful, and effective method for monitoring infrainguinal bypass grafts. The videotaped recordings of the intraoperative angioscopy studies of 25 failed infrainguinal bypass grafts inserted between May 1987 and July 1989 and 3 failing grafts that were angioscoped during the subsequent graft salvage procedure were reviewed in a systematic fashion according to a fixed protocol, to identify any endovascular findings either initially missed or in which the relevance to graft failure had been unappreciated at the time of bypass grafting. We were able to identify new venous pathologic characteristics and highlight endoluminal features, of both a technical and nontechnical nature, which have a probable causal relationship to graft failure. However, the significance of some of the endovascular findings that were seen during infrainguinal bypass grafting has yet to be fully defined.

Adult↗

Does the Kensey catheter keep a coaxial position inside the arterial lumen? An in-vitro angioscopic study.

Angioscopy was used to evaluate the "self-centering" ability of three Kensey catheters (KC) with different flexibility: one 8Fr "peripheral" and two 5Fr "coronary" (I & II). Angioscopic observations were made inside arteries, 5-18 mm in diameter. There was a good correlation between flexibility and self-centering of the KC [r = 0.83, p less than 0.05]. Increasing the flow rate of rinsing solution from 18 to 60 ml/min prolonged coaxial position from 8.9 +/- 3.3 to 36 +/- 2.2 sec/min of activation [p less than 0.001]. A smaller effect on coaxial position was exerted by increasing cam speed from 5.2 +/- 0.7 to 19.2 +/- 1.6 sec/min (p less than 0.001). In conclusion, angioscopy showed that the KC has a limited ability to maintain a coaxial position inside the arterial lumen and operators cannot rely on its self-centering property.

Angioplasty, Balloon, Coronary↗

Percutaneous angioscopic evaluation of luminal changes induced by excimer laser angioplasty.

Angioscopy has been shown to provide more detailed information on lesion morphology before and after interventional procedures than angiography. Therefore to evaluate the effects of laser angioplasty, angioscopy was performed in five patients with peripheral or coronary vascular disease who underwent excimer laser angioplasty. The excimer laser was operated at 308 nm, 135 nsec, 25 Hz, and 40 to 60 mjoules/mm2 and was coupled into multifiber wire-guided catheters of 1.4 to 2.0 mm diameter for coronary lesions and into catheters of 2.2 mm diameter for peripheral lesions. There were three coronary (one left anterior descending, one circumflex, one right coronary artery) and two peripheral (one common iliac artery, one superficial femoral artery) lesions. Angioscopy was successfully performed before and after laser ablation without any complications in all five lesions. The characteristics of angioscopic findings after excimer laser angioplasty consisted of flaps, fractures of plaques, and abundant tissue remnants. There was no apparent thermal injury. Recanalized channels were small and irregular. These results indicate that (1) angioscopy is effective and safe for evaluation of lesion morphology after laser angioplasty; (2) laser ablation does not result in thermal injury; and (3) irregular channels after recanalization and abundant tissue remnants may explain the suboptimal results after laser angioplasty.

Adult↗

Angioscopic detection of residual pulmonary thrombi in the differential diagnosis of pulmonary embolism.

Definite diagnosis of pulmonary embolism (PE) by conventional methods such as angiography is frequently difficult. If residual thromboemboli incorporated into the pulmonary arterial wall or in the distal small segments are visible, differential diagnosis of PE versus primary pulmonary hypertension (PPH) can be made without open-chest pulmonary biopsy. Six patients suspected of having acute PE, 6 suspected of having chronic PE, and 4 with PPH diagnosed by pulmonary biopsy underwent percutaneous pulmonary angioscopy. In patients suspected of having PE, globular and mural thromboemboli were detected by both angioscopy and angiography in 4 and 1 patients, respectively. By angioscopy, emboli incorporated into the arterial wall were detected in 7 and microemboli obstructing the distal small segments were detected in 6. However, these emboli were detected by angiography in none. In patients with PPH, no embolus was detected by angioscopy and angiography. Angioscopically, however, stenoses were observed in the distal small segments in all patients. The results indicate that residual pulmonary thromboemboli in PE and stenoses of distal pulmonary arteries in PPH are detectable by percutaneous angioscopy, and therefore this method is feasible for differential diagnosis of PE.

Acute Disease↗

Angioscopic findings during coronary angioplasty of coronary occlusions.

OBJECTIVES: This study sought to elucidate angioscopic findings in totally occluded vessels before and after intervention. BACKGROUND: Coronary angioscopy allows direct visualization of the lumen surface of the coronary arteries; however, the utility of coronary angioscopy during coronary angioplasty of vessels with a total occlusion is unknown. METHODS: Twenty-one consecutive patients (mean [+/- SD] 58 +/- 9 years, range 39 to 77; 3 women, 18 men) undergoing dilation of an occluded vessel were studied with coronary angioscopy. Occlusions were classified as functional in 8 patients (Thrombolysis in Myocardial Infarction [TIMI] flow grade 1) and anatomic in 13 (TIMI flow grade 0). Once the guide wire had crossed the occlusion, coronary angioscopy was attempted before and after angioplasty. RESULTS: In all patients, coronary angioscopy before dilation visualized protruding material occluding the coronary lumen where the guide wire was wedged. The occlusion consisted of red thrombus in 19 patients (90%) (2 with isolated occlusive thrombus, 17 with thrombus associated with atherosclerotic plaque) and protruding yellow plaque in 2 patients (10%). However, on angiography only 7 occlusions (33%) had data consistent with thrombus (p < 0.01 vs. coronary angioscopy). Successful dilation was obtained in 20 patients. After dilation, coronary angioscopy was repeated in 18 patients, revealing residual thrombus with plaque in 16 (89%) and a residual yellow plaque in 2. In addition, coronary angioscopy revealed coronary dissections in 13 patients (72%); however, angiography revealed dissections only in 10 patients (55%) and residual thrombus in 2 (10%) (p < 0.001). In one patient, coronary angioscopy visualized silent distal embolization of a red thrombus not previously recognized on angiography. CONCLUSIONS: Before intervention, coronary angioscopy provides unique insights into the pathologic substrate of occluded coronary vessels. An occlusive plaque with thrombus is the most common underlying substrate in these lesions. After successful dilation, angiographically silent mural thrombus is seen in most patients. This information could be used to assist in the selection of candidates and type of coronary interventions and could also prove to be of prognostic value in patients with occluded vessels.

Angioplasty, Balloon, Coronary↗

Incomplete neointimal coverage of sirolimus-eluting stents: angioscopic findings.

OBJECTIVES: The goal of this study was to use angioscopy to investigate the amount of neointimal coverage after sirolimus-eluting stent (SES) implantation. BACKGROUND: Sirolimus-eluting stents reduce intimal hyperplasia. METHODS: We used angioscopy to evaluate 37 consecutive stented coronary artery lesions (15 SES and 22 bare-metal stents [BMS]) in 25 patients (18 men, 7 women) at 3 to 6 months after stent implantation. Angioscopic evaluation focused on: 1) neointimal coverage of stent struts, and 2) the existence of thrombi. The degree of neointimal coverage was classified as grade 0 when there was no neointimal coverage (similar to immediately after the implantation); grade 1 when stent struts bulged into the lumen, but were covered and still translucently visible; grade 2 when stent struts were visible but not clearly seen (not translucent); and grade 3 when stent struts were not visible because they were embedded in the neointima. RESULTS: Thrombi were identified in eight stented segments, tended to be more common with SES (p = 0.14), but were not seen on angiography. Three of the 15 SES (20%) had grade 0 neointimal coverage, and only 2 SES (13.3%) had complete coverage (grades 2/3). In contrast, all 22 BMS showed complete intimal coverage (grades 2/3). Thrombi were more common in stents with incomplete neointimal coverage (p = 0.09). CONCLUSIONS: The SES had incomplete neointimal coverage three to six months after implantation, and this was associated with subclinical thrombus formation.

Aged↗

The healing process of infarct-related plaques. Insights from 18 months of serial angioscopic follow-up.

OBJECTIVES: To clarify the healing process of disrupted culprit plaques of acute myocardial infarction (MI), we serially observed the culprit plaques for 18 months after the onset of acute MI by angioscopy. BACKGROUND: Although it has been reported that disruption of the yellow plaque and subsequent thrombosis cause acute MI and that the thrombogenicity of the plaque lasts for a month, the healing process of the plaque after disruption has not been clarified. METHODS: Eighty-five patients with acute MI were prospectively and consecutively enrolled. Angioscopic studies were performed immediately and at 1, 6 and 18 months after successful reperfusion. The prevalence of yellow plaques and thrombus was examined. The color grade of the plaque was determined as 0 (white), 1 (light yellow), 2 (yellow) or 3 (bright yellow). RESULTS: Although yellow plaque was present at the culprit lesion in most patients throughout follow-up, its color grade was reduced from one to six months (1.9 +/- 0.6 vs. 1.1 +/- 0.7, p = 0.0003) after reperfusion, especially in the patients without hyperlipidemia (HL). The incidence of thrombus was 92.5% immediately after reperfusion, which was reduced significantly to 63.8%, 4.8% and 11.8% at 1, 6 and 18 months, respectively. The incidence of thrombus (77.8% vs. 45.0%, p = 0.03) at one month was higher in the patients with diabetes mellitus (DM). CONCLUSIONS: The healing process of yellow plaques at the culprit lesions of MI was detected by angioscopy as reductions of color grade and thrombogenicity at six months and partially at one month after the onset of acute MI. This healing process appears to deteriorate by complicating cases of DM or HL.

Aged↗

Angioscopic video-assisted pulmonary endarterectomy for post-embolic pulmonary hypertension.

OBJECTIVES: To assess whether the use of video-assisted angioscopy would increase the outcome of pulmonary thromboendarterectomy (PTE). METHODS: PTE included a median sternotomy, intrapericardial dissection of the superior vena cava, institution of cardiopulmonary bypass, deep hypothermia and sequential circulatory arrest periods. It was always performed through two separate arteriotomies on both main intrapericardial pulmonary arteries, into which a rigid 5 mm angioscope connected to a video camera was introduced to increase the visibility and endarterectomies. RESULTS: From January 1996 to July 1998, 68 consecutive patients (35 males and 33 females) aged 54.3 +/- 13.5 years underwent PTE. Patients were in New York Heart Association (NYHA) class II (n = 2), III (n = 43) or IV (n = 23) with the following hemodynamics: mean pulmonary arterial pressure (PAP) 54 +/- 13 mmHg; cardiac output (CO): 3.8 +/- 0.8 l/min, and total pulmonary resistance (TPR): 1207 +/- 416 dyne x s x cm(-5). The cumulated circulatory arrest time was 23 +/- 12 min and postoperative length of ventilatory support 10 +/- 12 days. Nine patients died, for an overall in-hospital mortality of 13.2%. The functional outcome in surviving patients was significantly improved (P < 0.0001) both clinically (NYHA class 3.2 +/- 0.5 vs. 1.3 +/- 0.6) and hemodynamically (PAP (mmHg) 53.1 +/- 13 vs. 30.2 +/- 11.8, CI (l/min per m2) 2.1 +/- 0.5 vs. 2.8 +/- 0.6, TPR (dyne x s x cm(-5)) 1174 +/- 416 vs. 519 +/- 250). CONCLUSIONS: Video-assisted angioscopy improves the quality and degree of pulmonary endarterectomy expanding the indications to include patients with previously inaccessible distal disease.

Adult↗

Angioscopic observations after percutaneous thrombectomy of thrombosed hemodialysis grafts.

PURPOSE: To use angioscopy to evaluate and compare the amount of residual thrombus and endoluminal wall damage in hemodialysis grafts after percutaneous thrombectomy procedures. MATERIALS AND METHODS: Thirty-nine thrombectomy and angioscopy procedures were performed in 35 patients. Percutaneous thrombectomy methods included eight different mechanical thrombectomy devices and the "lyse and wait" technique. Videotaped images of 33 angioscopic examinations were independently reviewed by three radiologists. Two parameters-the amount of residual thrombus and degree of endoluminal wall damage-were scored on a scale of 1 to 5. Data were initially analyzed to validate the grading system and then further studied to compare the different thrombectomy techniques. RESULTS: The Spearman rank order analysis validated the data pertaining to the amount of residual thrombus (r = 0.71, P < .0001), but there was poor correlation between reviewers regarding the degree of endoluminal wall damage. Combined scores from three reviewers revealed that the Cragg brush and Percutaneous Thrombectomy Device (PTD) left the smallest amounts of residual thrombus. The other methods tested, listed by increasing amount of residual thrombus, were the Endovac, Hydrolyser, Amplatz Thrombectomy Device, AngioJet, Oasis, and the lyse and wait technique. There were two complications related to angioscopy procedures. CONCLUSION: Subjective observations reveal that wall-contact thrombectomy devices leave less residual thrombus than hydrodynamic devices, aspiration devices, or the lyse and wait technique.

Angioscopy↗

[Simultaneous fluo-angioscope: a method for laser treatment close to the macula].

The Simultaneous Fluo-Angioscope is a compact optical device developed in clinical work as ancillary equipment for laser slit lamps. Both binocular and stereoscopic fluorescein angiograms can be directly overlaid onto the patient's fundus in the slit lamp in a 1-to-1 juxtaposition of angiographic data and fundus topography. In this way precise paramacular laser coagulation is achievable with a minimum of scotoma. The overlaying of earlier photos onto the present fundus also makes objective diagnosis of tumors, vessels, and other pathologically significant areas possible.

Fluorescein Angiography↗

Removal of focal atheromatous lesions by angioscopically guided high-speed rotary atherectomy. Preliminary experimental observations.

A new high-speed rotary atherectomy device, inserted over a guide wire and directed with an angioscope, offers the potential of restoring patency of outflow vessels by "boring out" the atheromatous lesion of the orifices of runoff vessels. The device was tested on 68 cadaver arteries with atheromatous lesions involving the superficial femoral, popliteal, and tibial arteries. This was performed with either free segments or in situ with the device placed through a popliteal arteriotomy. The gross results of rotary atherectomy were assessed by angioscopy, angiography, or both. The luminal surfaces were studied with scanning electron microscopy and transverse sections of vessels were studied with light microscopy. The pulverized atheroma, in colloidal suspension, was analyzed for particle size by Coulter counter. The effect of a colloidal suspension of atheromatous particles on distal capillary circulation was measured in animal experiments. Obstructive lesions were successfully removed in 36 of 37 stenotic arteries (97%) and 18 of 31 completely occluded arteries (58%), an overall efficacy of 54 of 68 (79%). In successfully atherectomized arteries, angioscopy and angiography demonstrated a widely patent, smooth, polished surface. Light microscopy demonstrated removal of the diseased intima with maintenance of the outer media and adventitia. The pulverized atheroma particles were generally smaller than red blood cells and injection of the colloidal atheroma into canine femoral arteries failed to produce local tissue injury. We conclude that in the human cadaver this atherectomy device effectively enlarges and recanalizes obstructed superficial femoral, popliteal, and tibial arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗

Angioscopic evaluation of unilateral aortic graft limb thrombectomy: is it helpful?

PURPOSE: Graft thrombectomy is often an effective method for restoring inflow in an occluded limb of an aortobifemoral graft. A major determinant for its success is the completeness of thrombus removal from the graft, verification of which can be performed by angioscopy. METHODS: A retrospective review since January 1989 identified 51 unilateral graft limb thrombectomy operations in 35 patients. At the discretion of the surgeon 20 of these procedures included angioscopic inspection of the graft for significant retained thrombus, which was found and retrieved in 11 (55%). RESULTS: Visualization of the graft limb was very good, but inspection of the graft body was not possible. There were no angioscopy-related complications. Within the first 4 months after graft limb thrombectomy and reconstruction, four of 20 patients in the group inspected by angioscopy and nine of 31 in the conventionally treated group had reocclusion of the treated limb. CONCLUSIONS: These results suggest that angioscopy can be a helpful adjunct in the successful inflow management of aortic graft limb thrombectomy to verify the completeness of clot removal.

Angioscopy↗

Pathophysiology of unstable angina pectoris--correlations with coronary angioscopic imaging.

Different patho-anatomical and functional factors are considered to be involved in patients with unstable angina pectoris. Among these are a pre-existing plaque based on coronary atherosclerosis, the development of fissures or dissections of the plaque (often combined with thrombus formation at the site of the plaque) coronary vascular tone, and theoretically primary aggregation of platelets at a site of apparently normal vascular endothelium. Several comprehensive studies on patients who died from acute myocardial infarction or unstable angina, have convincingly shown that complications of an atherosclerotic plaque like fissures, dissections and thrombus formation may be present in 60 to 90% of cases. In addition, two groups of investigators, who have applied coronary angioscopy for direct visualization of offending coronary arteries, have confirmed these results, since in about 60-80% of patients with unstable angina complicated atheromata, i.e. rupture, ulceration, thrombus formation, could be documented, whereas in all patients with stable angina an uncomplicated atheroma was seen angioscopically. On the basis of these results a hypothetical sequence of events in patients with stable angina, unstable angina and acute myocardial infarction has been proposed. Stable angina pectoris may be seen in patients with uncomplicated atheroma in one of the major coronary artery branches. When dissections, ulcerations and thrombus formation occur as a complication of a formerly smooth plaque, patients show the clinical syndrome of unstable angina. If an occlusive thrombus develops, the patient will run into a fresh myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗

Carbon dioxide as an angioscopic medium. Comparison to various methods of saline delivery.

The limitations of angiography, when it is used as the sole method of vascular assessment, are increasingly apparent as vascular intervention becomes more sophisticated. Angioscopy could be an adjunctive diagnostic modality by differentiating among thrombus, dissection, and atheroma, and by monitoring the response to therapy. However, angioscopy requires a blood-free field for adequate visibility, and this may be difficult to obtain. The feasibility of carbon dioxide (CO2) and various saline delivery methods for clarifying the viewing field for percutaneous angioscopy was investigated. Angioscopy of femoral and iliac arteries on nine dogs was performed. Saline was infused by hand injection, pressure bag infusion, or mechanical power injection, and CO2 gas was injected using a special gas injector. The clarity of the viewing field was graded for each medium and method. Excellent quality antegrade femoral angioscopy was obtained with CO2. The superiority of CO2 injection in comparison with power-injected saline approached statistical significance (P = .06). Power-injected CO2 and power saline were superior to hand-injected or pressure bag-injected saline for maintaining sufficient visibility. Retrograde iliac angioscopy was possible without inflow occlusion, but required high flow rates (only possible with power-injected saline or CO2). CO2 injected under controlled circumstances holds promise as a medium to improve angioscopic visibility.

Angiography↗

Unstable angina. A comparison of angioscopic findings between diabetic and nondiabetic patients.

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.

Aged↗

Laser recanalization of thrombosed arteries using thermal and/or modified optical probes; angiographic and angioscopic study.

The degree of residual stenosis by fresh thrombus after laser recanalization was compared by use of angiography and angioscopy. Fifteen NZW rabbits were used. Occlusive fresh thrombus in rabbit aorta was produced by mechanical deendothelialization and external constrictions simulating clinical situations. Argon laser angioplasty using microlens-tipped optical fiber and/or 2 mm hot-tip probe was done to recanalize thrombosed aorta in 10 animals. Two-mm hybrid probe was used in 5. Percent area stenosis (% AST) was derived by use of the mean radius method obtained by angiography of stenotic segments in two orthogonal views and/or from angioscopy. All 15 totally occluded vessels with fresh thrombus were recanalized. Four minor perforations occurred. Following argon laser angioplasty with the microlens optical fiber, percent stenosis was reduced to 53% in diameter by angiography and 66 in % AST by angioscopy, and to 48% and 55 respectively following hot-tip probe. After laser angioplasty with the hybrid probe, residual stenosis by fresh thrombus was 37% in diameter on angiography and 63 in % AST on angioscopy. Mean percent AST was 62% with angiography and 52% with angioscopy, and there was no correlation between them (r = -0.028). Angioscopy provided cross-sectional topographic views of thrombosed lumen and showed charring and shrinkage of thrombus following laser angioplasty. This study suggests that (1) continuous-wave laser angioplasty using modified optical fibers can recanalize thrombotic vascular occlusion, (2) laser angioplasty by hot-tip probe could evacuate fresh thrombus more than microlens fiber on angioscopy, and (3) angiographic % AST did not correlate with angioscopic % AST.

Angiography↗

Mechanism of rethrombosis after thrombolytic therapy: angioscopic findings and investigation of the coagulation system in dogs.

The purpose of this study was to angioscopically observe the process of thrombolysis after intracoronary administration of thrombolytic agents and to investigate the effects of these agents on coagulation/fibrinolysis systems in dogs. The coronary endothelium was removed and thrombus formation was confirmed by angioscopy. In the tissue plasminogen activator (tPA) group (n=8), complete thrombolysis occurred in all animals, but thrombolysis was incomplete in the urokinase (UK) group (n=6). The plasma level of plasmin alpha2-plasmin inhibitor complex peaked at 15 minutes after treatment in both the tPA and UK groups. Plasma thrombin-antithrombin III (TAT) complex decreased transiently at 15 minutes after tPA administration but increased at 30 and 60 minutes (P<0.05). In the UK group, plasma TAT also showed a transient decrease followed by an increase, which was minimal compared with that in the tPA group. Plasma TAT decreased transiently after infusion of tPA and subsequently increased to above the pretreatment level, suggesting a risk of rethrombosis after successful recanalization.

Angioscopy↗