Rupture during treatment of recently ruptured aneurysms with Guglielmi electrodetachable coils

BACKGROUND AND PURPOSE: We describe four cases of aneurysmal rupture during embolization with Guglielmi electrodetachable coils (GDCs) in an attempt to identify those aneurysms whose rupture during embolization represents a life-threatening risk; our emphasis is on emergency management, in particular, ventriculostomy. METHODS: Medical records were reviewed retrospectively for 91 aneurysms treated with GDCs 0 to 21 days after subarachnoid hemorrhage. Rupture was ascertained by the presence of extravascular effusion of contrast medium. RESULTS: Of the perforated aneurysms, two involved the anterior communicating artery, one the posterior inferior communicating artery, and one the basilar artery. Only two patients, whose aneurysms were located in the posterior fossa, had major complications (arterial hyperpressure, mydriasis, angiographically documented circulatory arrest or slowing). One of these patients died and the other improved after emergency ventriculostomy. CONCLUSION: Aneurysmal perforation during embolization may be accompanied by severe intracranial hypertension, which causes either a decrease or arrest of cerebral perfusion, the duration of which determines clinical outcome. Emergency ventriculostomy (which should be performed in the angiographic suite) is an effective means to reduce intracranial pressure. Recognition of aneurysms associated with a high risk of mortality by rupture in the course of embolization (recently ruptured small aneurysms, posterior fossa aneurysms, associated ventricular dilatation, massive cisternal hemorrhage) and use of proper logistics should ensure the effective management of this devastating complication.     

Initial experience with collagen-filled Guglielmi detachable coils for endovascular treatment of experimental aneurysms

PURPOSE: To evaluate the effectiveness of Guglielmi detachable coils (GDCs) filled with collagen threads in the permanent treatment of experimental aneurysms. METHODS: Seventeen side-wall aneurysms were surgically constructed in the canine common carotid artery; six were treated with conventional GDCs and 11 with collagen-filled GDCs. One aneurysms was removed at 1 week, the others were studied by digital subtraction angiography for a period of 8 to 12 weeks. Longitudinal sections of all aneurysms were examined by light microscopy. RESULTS: Angiograms obtained throughout the follow-up period showed no significant difference between aneurysms treated with conventional GDCs and those treated with collagen-filled GDCs. Light microscopy revealed a dense meshwork of newly formed collagen and fibroblasts near the collagen-filled GDCs, whereas a loose cellular meshwork surrounded the conventional GDCs at 8 and 12 weeks after treatment. CONCLUSION: Collagen threads within GDCs do not noticeably improve angiographic treatment of experimental aneurysms; however, these threads did induce local proliferation of fibroblasts and production of collagen within the aneurysmal cavities.     

Establishing germ cell origin of undifferentiated tumors by identifying gain of 12p material using comparative genomic hybridization analysis of paraffin-embedded samples

BACKGROUND: External carotid arteriovenous fistulas (AVFs) are rare and most hospitals have limited experience with their management. This study was designed to evaluate the effectiveness and safety of endovascular embolization of AVFs of the external carotid artery under angiographic control. METHODS: A series of 13 patients with AVFs involving the branches of the external carotid artery, all treated with endovascular embolization, were reviewed. There were 10 males and three females ranging in age from nine to 46 years, with a mean of 27 years. The most frequent presenting symptoms were pulsatile tinnitus, followed by bruit and/or thrill, ocular problems, headache and a pulsatile mass in the neck. The middle meningeal artery was most often involved, followed by the internal maxillary artery and the occipital artery. The AVFs were caused by trauma in 10 patients and occurred spontaneously in three. N-butyl-2-cyanoacrylate was used to embolize the fistula in 11 patients and a detachable balloon was used in two. RESULTS: All the patients were cured and no significant complications were observed. No recurrence was noted after a clinical follow-up of three months to seven years (mean, 37 months). CONCLUSIONS: Endovascular embolization proved to be a safe and effective procedure. It should be the treatment of choice for repair of external carotid AVFs.     

Runt determines cell fates in the Drosophila embryonic CNS

BACKGROUND AND PURPOSE: Our purpose was to evaluate the ability of transcranial color-coded Doppler sonography (TCCD) to 1) identify Guglielmi detachable coils (GDCs) within intracranial aneurysms, 2) show endovascular aneurysmal occlusion and patency of parent and branch arteries, 3) determine the flow velocities within parent arteries and major branches before and after treatment, and 4) assess persistence of aneurysmal occlusion. METHODS: The sonographic appearance of GDCs was established experimentally by TCCD (2 to 2.5 MHz), which was then performed in 40 patients with 43 aneurysms occluded by GDCs. The patency of parent arteries and major branches was assessed qualitatively and compared with the immediate posttherapeutic angiographic appearance in every patient. Flow velocities were selectively measured and compared before and after treatment in 21 parent arteries and 24 major branches. Follow-up TCCD studies performed in 26 patients were compared with angiographic (16 cases) and MR angiographic (10 cases) findings for signs of recanalization of the treated aneurysms. RESULTS: The GDCs were identified experimentally and in the patients as hyperechoic structures of the size and shape, and in the location of, the treated aneurysm in 41 of 43 cases. TCCD in accordance with angiography showed a lack of flow in 42 aneurysms and the presence of flow signal in one large aneurysm. Patency of the parent artery was shown in 40 aneurysms and in all branches. Follow-up TCCD showed the coils unchanged in 23 of 26 cases. In three large aneurysms, TCCD indicated recanalization and reappearance of a flow signal separate from the parent artery. CONCLUSION: TCCD is a reliable, noninvasive means to assess parent artery and major branch patency and to reveal a lack of hemodynamic compromise in the vicinity of aneurysms after endovascular therapy. On follow-up examinations, TCCD was able to detect signs of aneurysmal recanalization.     

Cervical vascular injuries: a trauma center experience

BACKGROUND: We analyzed 76 patients with cervical vascular injuries from penetrating neck trauma (n = 528) between 1977 and 1990 at a level I trauma center to evaluate the role of angiography in diagnosis and management and to assess the course and outcome of these patients. METHODS: Patients who were hemodynamically unstable underwent immediate surgical exploration. Stable patients were subjected to diagnostic investigation. Angiography was routinely performed to diagnose vascular injury in zones I and III and zone II if the trajectory was in the vicinity of major vessels. Therapeutic embolization was performed when possible at angiography; all other vascular injuries were treated surgically. RESULTS: Thirteen patients (2.5%) died of penetrating neck trauma, in 12 of whom hemorrhage was the contributing factor (12/76; 15.8% of patients with vascular injury). In nine patients who were hemodynamically stable vascular injury was diagnosed by angiography: 5 (6.8%) of 73 in zone I and 3 (5.4%) of 56 in zone III, four of whom underwent therapeutic embolic occlusion of the injured vessel. Injuries to vertebral and subclavian arteries and subclavian and innominate veins were often multiple, causing exsanguination and death (6.8% in zone I). In three patients with no preoperative neurologic deficit, the internal carotid artery was ligated without complication; in all other patients injury to the common carotid or internal carotid artery was repaired, in six of them with polytetrafluoroethylene grafts. CONCLUSIONS: Selective management of penetrating neck trauma should include routine angiography in zones I and III. Injuries to the common and internal carotid arteries should be repaired. The internal carotid artery may be ligated in the absence of preoperative neurologic deficit. Arterial injuries in the neck can be repaired with polytetrafluoroethylene grafts.     

Spontaneous closure of selected iatrogenic pseudoaneurysms and arteriovenous fistulae

PURPOSE: We report our approach to the management of postcatheterization femoral artery pseudoaneurysms and arteriovenous fistulae in an attempt to determine the frequency of spontaneous resolution of selected lesions. METHODS: We studied 196 pseudoaneurysms, 81 arteriovenous fistulae, and 9 combined lesions that were identified by duplex scan. Indications for immediate surgical repair included pseudoaneurysm greater than 3 cm, enlarging hematoma, pain, groin infection, nerve compression, limb ischemia, concomitant surgical procedure, and patient refusal or inability to comply with follow-up. All other lesions were observed. RESULTS: One hundred thirty-nine patients underwent prompt surgical repair, and 147 patients were initially managed without operation. There were no limb-threatening complications associated with nonoperative management in this subset of patients. Eighty-six percent of the lesions being observed resolved spontaneously within a mean of 23 days, whereas 14% required surgical closure for a variety of reasons (at a mean of 111 days after the initial diagnosis). There was no statistically significant difference in the rate of spontaneous pseudoaneurysm closure (89%) as opposed to fistulae (81%) (p < 0.17). By life-table analysis, 90% of selected pseudoaneurysms had resolved by 2 months. Patients selected for observation underwent an average of 2.6 duplex scans per patient versus 1.4 scans per patient for those treated with immediate surgery (p < 0.01). CONCLUSION: The natural history of stable pseudoaneurysms and arteriovenous fistulae is benign and frequently results in spontaneous resolution, which allows properly selected patients to be managed without operation.     

Expression of CD1a monocytes cultured with supernatants from periodontally diseased gingival epithelial cells

MATERIAL AND METHODS: We evaluated the role of color Doppler US-guided compression in the non-invasive treatment of femoral artery pseudoaneurysms after cardiac catheterization, including 22 PTCA procedures. The diagnosis of 32 pseudoaneurysms in 32 patients was accomplished by detection of the typical US-Doppler pattern consisting of the swirling color Doppler flow and the "to and fro" pulsed Doppler waveform at a mean 3.6 days (1 to 14) after the cardiac catheterization. Thirteen patients had multiple cavity pseudoaneurysms (2 to 4). All the patients immediately underwent compression therapy. RESULTS: Treatment was successful in 42/49 cavities (86%) and 25/32 patients (78%), usually after 1 to 3 compression cycles of 6 to 8 minutes duration. Only one recurrence was noted at the 24 hour US-Doppler follow-up. In all cases, pain relief during compression was an excellent clinical sign of hemostatic plug formation and conversion from pseudoaneurysm to simple hematoma. Failures occurred among patients under high dose anticoagulants in spite of 4 to 10 compression cycles. COMMENTARY: In conclusion, color Doppler US-guided compression of post-cardiac catheterization pseudoaneurysms should be the first line therapeutic modality, even in cases of multiple cavities and among patients under effective anticoagulation therapy.     

Improved success in nonoperative management of blunt splenic injuries: embolization of splenic artery pseudoaneurysms

OBJECTIVES: By using abdominal computed tomographic scans in the evaluation of blunt splenic trauma, we previously identified the presence of vascular blush as a predictor of failure, with a failure of nonoperative management of 13% in that series. This finding led to an alteration in our management scheme, which now includes the aggressive identification and embolization of splenic artery pseudoaneurysms. METHODS: The medical records of 524 consecutive patients with blunt splenic injury managed over a 4.5-year period were reviewed for the following information: age, Injury Severity Score (ISS), American Association for the Surgery of Trauma splenic injury grade (SIG), method and outcome of management. RESULTS: Of the patients, 66% were male with a mean age of 32 +/- 16, and mean ISS of 25 +/- 13. A total of 180 patients (34%) were managed with urgent operation on admission (81% splenectomy (SIG 4.0), 19% splenorrhaphy (SIG 2.6)). The remaining 344 patients (66%) were hemodynamically stable and underwent computed tomographic scan and planned nonoperative management. Of these patients, 322 patients (94%) were successfully managed nonoperatively (61% of total splenic injuries). In 26 patients (8%), a contrast blush identified on computed tomographic scan was confirmed as a parenchymal pseudoaneurysm on arteriography. Twenty patients (SIG, 2.8) were successfully embolized. In six patients, technical failure precluded embolization; all required splenectomy (SIG, 4.0). A total of 22 patients (6%) failed nonoperative management, including the six with unsuccessful embolization attempts. Sixteen patients (SIG, 3.0) who had no evidence of pseudoaneurysm were explored for a falling hematocrit, hemodynamic instability, or a worsening follow-up computed tomography: 13 patients had splenectomy, and three patients had splenorrhaphy. CONCLUSIONS: Aggressive surveillance for and embolization of posttraumatic splenic artery pseudoaneurysms improved the rate of successful nonoperative management of blunt splenic trauma to 61%, with a nonoperative failure rate of only 6%. In comparison with our previous work, this reduction in failure of nonoperative management is a significant improvement (p < 0.03).     

Endovascular surgical approach to intracranial vascular diseases

PURPOSE: The endovascular surgical approach to complex disorders of the central nervous system has made rapid and significant advancements over the past decade. Patients with intracranial arterial aneurysms, traumatic carotid and vertebral artery lesions, including fistulas and pseudoaneurysms, hemodynamically significant atherosclerotic lesions, vasospasm, and acute stroke are now being approached and treated by newer and less invasive techniques, including cerebral angioplasty and thrombolytic therapy. METHODS: All procedures are usually performed from a transfemoral approach utilizing a variety of occlusion devices, including detachable silicone balloons, microcoils, electrolytic detachable coils, liquid tissue adhesives, and particulate emboli for vessel occlusion. For dilatation and reperfusion of vessels, balloon angioplasty catheters, stents, and thrombolytic drugs are being used. RESULTS: For the treatment of traumatic vascular injuries, such as carotid cavernous sinus fistulas and vertebral arteriovenous fistulas and pseudoaneurysms, endovascular therapy has become the treatment of choice. The endovascular approach for intracranial aneurysms is emerging as a therapeutic option in selected cases. For occlusive disorders in patients presenting with acute cerebral ischemia, extracranial angioplasty and cerebral thrombolysis techniques are currently under investigation. CONCLUSIONS: As these techniques continue to evolve, the field of interventional neuroradiology will expand the therapeutic options for managing complex cerebrovascular disorders and improve patient outcome in acute stroke therapy.     

Amaurosis fugax and carotid artery disease: indications for angiography

A prospective study of 80 patients presenting with amaurosis fugax was performed in an attempt to relate clinical features to angiographic findings in the internal carotid artery. Carotid bruit, transient cerebral ischaemic attacks, hypertension, and claudication were associated with a high prevalence of angiographic abnormality. Every patient who showed all these features had an operable lesion, as did 88% of those who had three features. In patients over 50 years of age carotid stenosis and atheromatous ulceration were occasionally found in the absence of bruit and transient cerebral ischaemia, but only one patient aged under 50 had an operable lesion and no associated features. Clinical features were therefore valuable in predicting the outcome of angiography, but it seems prudent to restrict angiography to patients aged over 50, who are most likely to benefit from surgery on the carotid artery.     

Immunoaffinity column as cleanup tool for a direct competitive enzyme-linked immunosorbent assay of cyclopiazonic acid in corn, peanuts, and mixed feed

PURPOSE: Atherothrombotic occlusion of the cervical internal carotid artery (ICA) without collateral flow is one of the most critical forms of acute ischemia. We report the results of urgent thrombolytic treatment of patients with major stroke in this clinical category. METHODS: Clinical findings and outcome in 33 patients were investigated. All patients had suffered a major stroke, with a score of 24 or higher on the NIH Stroke Scale on admission. Ischemic abnormalities were not detected on initial CT studies. Diagnoses were made at angiography, and patients were treated by intravenous or intraarterial local thrombolysis within 6 hours of stroke onset. RESULTS: Recanalization was accomplished in eight patients with intraarterial local thrombolysis; four of these patients had a good clinical outcome. Two factors characteristic of those whose treatment was successful were dramatic improvement of symptoms after partial recanalization achieved within 3 hours of onset and stabilized improvement after subsequent percutaneous transluminal angioplasty or carotid endarterectomy for residual atherosclerotic stenosis at the ICA origin. CONCLUSION: The results of this study suggest that urgent intraarterial local thrombolysis may be a successful treatment method for some patients in this critical clinical category if the treatment can be accomplished within 3 hours of ictus and followed by either angioplasty or endarterectomy for residual stenosis.     

Geographic distribution of leukemia mortality in young people aged 0-24 years in France

Patients with significant stenosis at the carotid bifurcation are traditionally subjected to four vessel aortic arch angiography prior to consideration for carotid endarterectomy. The advent of the non-invasive vascular laboratory has necessitated a reappraisal of this approach. AIMS: 1. Determine the yield from aortic arch angiography and its influence on surgical management. 2. Evaluate the accuracy of clinical examination and the non-invasive vascular laboratory in the detection of aortic arch branch lesions. METHODS: One hundred and twenty-nine consecutive patients undergoing evaluation for carotid endarterectomy were prospectively enrolled into the study. The protocol entailed: 1. Clinical recording of upper limb pulses, blood pressure and supraclavicular bruits. 2. Duplex scan examination to evaluate proximal inflow into the carotid arteries. 3. Four vessel aortic arch angiography to detect aortic branch lesions. Data from the non-invasive tests were compared to angiography. Patients with aortic arch branch lesions were further evaluated to determine the proportion requiring additional surgery. RESULTS: Nineteen patients had angiographic evidence of aortic branch disease (14.7%); six involved the common carotid artery, three the innominate artery and 10 the subclavian artery. All of these lesions were detected by the combination of unequal blood pressure, pulse deficit, bruit or duplex scan. Seven patients underwent additional surgery (5.4%) which included carotid-subclavian bypass (five), aortoinnominate bypass (one) and innominate endarterectomy (one). CONCLUSION: In patients with significant stenosis at the carotid bifurcation undergoing evaluation for carotid endarterectomy, aortic arch angiography is unnecessary except in a small percentage of patients with abnormal clinical and non-invasive findings.     

Structural motif and characteristics of the extracellular domain of P2X receptors

OBJECTIVES: We attempted to evaluate nonsurgical methods of treating postcatheterization pseudoaneurysm. BACKGROUND: The value of reapplication of a compression bandage, ultrasound-guided compression repair (UGCR) and awaiting spontaneous thrombosis in the treatment of postcatheterization pseudoaneurysms is unsettled. METHODS: We followed a stepwise treatment strategy of primarily conservative management using 1) reapplication of a compression bandage, followed by 2) UGCR, if needed, and 3) observation of the natural course. Surgical repair was reserved for patients with a rapidly expanding or complicated lesion. RESULTS: Reapplication of a compression bandage was performed in 128 patients and was successful in 32%. The success rate correlated inversely with anticoagulant therapy and the size of the aneurysm. In case of failure this pretreatment with a compression bandage significantly enhanced the success rate of subsequent UGCR (p = 0.04). UGCR was performed in 124 cases with a success rate of 84%. In 54 patients with a stable lesion, refraining from any (further) active measures resulted in spontaneous thrombosis of the aneurysm in 50 patients (93%) after 1 to 180 days (median 40 days). The course of the remaining four femoral artery aneurysms was uneventful. Definitive repair by operation or collagen plug implantation was required in only 20 patients (9%). CONCLUSIONS: The first measure performed in the treatment of pseudoaneurysms should be reapplication of a compression bandage, followed, if necessary, by UGCR. After failure of UGCR, spontaneous healing occurs in the majority of patients. Operation can be reserved for progressive and complicated lesions.     

US-guided pseudoaneurysm repair with a compression device

A simple commercially available compression device allowed intermittent ultrasound scanning of the compression site during compression repair of a femoral artery pseudoaneurysm in six patients. All six of the pseudoaneurysms (five superficial femoral and one common femoral) were compressed without compression of the underlying vessels. The procedure was successful in four of the six patients, without complications. Use of this device may decrease operator fatigue during compression repair of pseudoaneurysm.     

Transforming growth factor-beta1 in hemangioma of the ovary

OBJECTIVE: Anastomotic pseudoaneurysms continue to be a late complication of vascular surgery, particulary following prosthetic graft procedures. The purpose of this study was to investigate if a previously reported increase in interval between the original operation and the development of pseudoaneurysm was related to a change in incidence. DESIGN: Retrospective study. METHODS: We reviewed the records of 76 patients who presented with 90 femoral pseudo-aneurysms and underwent reconstructive procedures from January 1989 to June 1994. The median age was 69 years (range: 39-83). In the same time period all femoral artery anastomosis operations were recorded. RESULTS: The incidence of femoral pseudo-aneurysms in Copenhagen was approximately 4.3%. CONCLUSIONS: A previously reported increase in interval between primary operation and aneurysms formation was not related to a change in incidence during the same time period.     

Effectiveness of transcatheter embolization in the control of hepatic vascular injuries

PURPOSE: The authors describe their 11-year experience with transcatheter embolization (TCE) in the treatment of patients with hemorrhagic hepatic injuries. PATIENTS AND METHODS: Twenty-eight TCE procedures were performed in 24 patients between 1980 and 1991. Injuries in 21 patients were due to vehicular or criminal trauma; in three patients, injuries were iatrogenic. There were 21 male and three female patients (age range, 6-64 years). All patients underwent angiography and had evidence of active hemorrhage, pseudoaneurysm, or arteriovenous fistula (AVF). All embolizations were performed with use of Gianturco coils, microcoils, or gelatin sponge. RESULTS: TCE was technically successful in occluding hepatic vascular lesions in 21 of 24 patients (88%). Technical failures were due to the inability to select the appropriate vessel for embolization in two cases and due to a persistent AVF that did not occlude despite further attempts at embolization. Lesions recurred in two patients who underwent initially successful TCE. Both patients were treated effectively with repeated TCE. Only two catheter-related complications were encountered, both after successful TCE. Twenty-one patients survived to be discharged from the hospital. Two patients among the group treated successfully and one from the group in whom treatment failed died. CONCLUSION: This experience demonstrates that TCE is effective in the management of hepatic vascular injuries due to trauma.     

Embolization of cerebral aneurysms using Guglielmi detachable coils--problems and treatment plans in the acute stage after subarachnoid hemorrhage and long-term efficiency

This study investigated the problems in treating ruptured aneurysms using Guglielmi detachable coils (GDCs) in the acute stage and evaluated the long-term efficacy in a series of 25 patients with 29 aneurysms. Eight patients with ruptured aneurysm treated within 2 weeks of the onset of subarachnoid hemorrhage (SAH) suffered no mortality or morbidity related to the procedure. Five patients achieved good outcomes despite severe SAH and returned to their previous lives. Three patients had poor clinical outcomes, two related to vasospasm and one related to pulmonary complication. More than 9 months follow-up was completed in 14 patients with 16 aneurysms. All six small aneurysms with small necks were completely obliterated and no recanalization was seen, and two of the eight large or giant aneurysms were completely obliterated. Recanalization was seen in four large or giant aneurysms and one small aneurysm due to coil compaction within 13 months. One patient died of rupture of a large aneurysm 18 months after complete obliteration of the aneurysm. Embolization using GDCs in the acute stage after SAH can prevent rerupture of cerebral aneurysms. However, recanalization due to coil compaction was the major problem in the chronic stage. Intensive follow-up and additional embolization, if necessary, is important.     

Aneurysms of the subclavian artery: clinical experience

The aneurysm of the subclavian artery is not common. The authors present three cases of aneurysms of the subclavian artery of which two cases already were in phase of complication for rupture. Two Patients underwent intervention of by-pass with Dacron prosthesis: between common carotid and axillary artery in one and between common carotid and distal head of the subclavian artery in the other. In a Patient with post-traumatic pseudoaneurysm of the subclavian artery was not possible to perform any intervention of direct reconstruction because of the precarious clinical conditions due to the hemorrhage for rupture and we performed only a resection of the aneurysm with binding of the subclavian artery. A Patient died two months after the operation for respiratory failure due to bronchial pneumonia; two Patients are still living, one with a moderate motor deficit of the upper limb. The rupture of the arteriosclerotic aneurysms of the subclavian artery is not frequent, but the gravity of this complication recommends the surgical treatment also in the asymptomatic cases if the clinical conditions of the Patient allow it.     

Prevention of postoperative thrombotic stroke after carotid endarterectomy: the role of transcranial Doppler ultrasound

PURPOSE: To determine the incidence of particulate embolization after carotid endarterectomy (CEA), the effect of dextran-40 infusion in patients with sustained postoperative embolization, and the impact of transcranial Doppler (TCD) monitoring plus adjuvant dextran therapy on the rate of postoperative carotid thrombosis. METHODS: Prospective study in 100 patients who underwent CEA with 6-hour postoperative monitoring using a TCD that was modified to allow automatic, intermittent recording from the ipsilateral middle cerebral artery waveform (10 minute sample every 30 minutes). An incremental dextran-40 infusion was commenced if 25 or more emboli were detected in any 10-minute period. RESULTS: Overall, 48% of patients had one or more emboli detected in the postoperative period, particularly in the first 2 hours. However, sustained embolization that required Dextran therapy developed in only five patients. In each case, the rate of embolization rapidly diminished. CONCLUSIONS: A small proportion of patients have sustained embolization after CEA, which in previous studies has been shown to be highly predictive of thrombotic stroke. Intervention with dextran reduced and subsequently stopped all the emboli in those in whom it was used and contributed to a 0% perioperative morbidity and mortality rate in this series.     

Quantitative detection of Sphingomonas chlorophenolica in soil via competitive polymerase chain reaction

PURPOSE: To develop an ex vivo human carotid artery stenting model that can be used for the quantitative analysis of risk for embolization associated with balloon angioplasty and stenting and to correlate this risk with lesion characteristics to define lesions suitable for balloon angioplasty and stenting. METHODS: Specimens of carotid plaque (n = 24) were obtained circumferentially intact from patients undergoing standard carotid endarterectomy. Carotid lesions were prospectively characterized on the basis of angiographic and duplex findings before endarterectomy and clinical findings. Specimens were encased in a polytetrafluoroethylene wrap and mounted in a flow chamber that allowed access for endovascular procedures and observations. Balloon angioplasty and stenting were performed under fluoroscopic guidance with either a Palmaz stent or a Wallstent endoprosthesis. Ex vivo angiograms were obtained before and after intervention. Effluent from each specimen was filtered for released embolic particles, which were microscopically examined, counted, and correlated with various plaque characteristics by means of multivariate analysis. RESULTS: Balloon angioplasty and stenting produced embolic particles that consisted of atherosclerotic debris, organized thrombus, and calcified material. The number of embolic particles detected after balloon angioplasty and stenting was not related to preoperative symptoms, sex, plaque ulceration or calcification, or artery size. However, echolucent plaques generated a higher number of particles compared with echogenic plaques (p < 0.01). In addition, increased lesion stenosis also significantly correlated with the total number of particles produced by balloon angioplasty and stenting (r = 0.55). Multivariate analysis revealed that these two characteristics were independent risk factors. CONCLUSIONS: Echolucent plaques and plaques with stenosis > or = 90% produced a higher number of embolic particles and therefore may be less suitable for balloon angioplasty and stenting. This ex vivo model can be used to identify high-risk lesions for balloon angioplasty and stenting and can aid in the evaluation of new devices being considered for carotid balloon angioplasty and stenting.