Biomedical subjects

Fernando Viñuela

Publications and source records attributed to Fernando Viñuela.

At least 19 recordsLinked to original sources

PubMed2006

Nongalenic arteriovenous fistulas: history of treatment and technology.

Nongalenic cerebral arteriovenous fistulas (AVFs) are uncommon, high-flow vascular lesions first treated by Walter Dandy and his colleagues by using open surgery with ligation of the feeding artery. Due to advances in endovascular technology over the past four decades that make possible the control of high flow in AVFs, treatment has evolved from the sole option of surgery to include the alternative or adjunct option of endovascular embolization. The authors of this review discuss the history of nongalenic AVF treatment, including techniques of both surgery and interventional neuroradiology and the technological developments underlying them.

Diagnostic Techniques, Neurological↗

PubMed2006

Challenges in the endovascular treatment of giant intracranial aneurysms.

OBJECTIVE: Giant intracranial aneurysms present unique therapeutic intricacies. The purpose of this study was to evaluate the anatomic and hemodynamic characteristics of these lesions and the current endovascular and combined surgical and endovascular techniques available for their treatment. METHODS: A review of the literature and the personal experiences of the authors with endovascular treatment of giant aneurysms are presented. This review included anatomic and hemodynamic features and analysis of the diverse endovascular techniques that have been reported for the management of these aneurysms. RESULTS: Anatomic features that create particular challenges in the therapeutic approach of giant aneurysms include size, shape (saccular, fusiform, serpentine), neck dimensions, branch involvement, intraluminal thrombosis, and location. Hemodynamic characteristics that affect endovascular treatment are lateral or terminal aneurysm type of flow and embolic material placement (inflow versus outflow aneurysmal region). The current endovascular therapeutic approaches include parent artery occlusion, trapping, endosaccular embolization with or without adjunctive techniques such as balloon-assisted or stent placement, and combined surgical and endovascular approaches, mainly with surgical revascularization and endovascular occlusion. CONCLUSION: Although there are a wide variety of endovascular therapeutic options for the treatment of giant intracranial aneurysms, none of the current techniques is completely successful and free of complications in the management of these complex lesions. A detailed and individualized analysis of each case in conjunction with sufficient understanding of the anatomy and hemodynamics of a particular aneurysm should guide the therapeutic decision. Further research advances will assist in elucidating the factors predisposing to genesis, progression, and aggressive clinical manifestations of these giant lesions.

Blood Vessel Prosthesis↗

PubMed2006

Initial clinical experience with matrix detachable coils for the treatment of intracranial aneurysms.

OBJECT: The Matrix detachable coil is a new bioactive, bioabsorbable coil used in the endovascular embolization of intracranial aneurysms. It has a platinum core covered with a bioactive, bioabsorbable polymer (polyglycolic acid/lactide). The authors report on their initial midterm clinical experience with the first-generation Matrix detachable coil. METHODS: One hundred twelve patients harboring 118 aneurysms were treated using Matrix coils. Forty-nine aneurysms (41.5%) were associated with acute subarachnoid hemorrhage (SAH). Twenty-four lesions (49%) were harbored by patients with Hunt and Hess Grade I, 11 (23.4%) by patients with Grade II, eight (16.3%) by those with Grade III, and six (12.2%) by those with Grade IV. Four aneurysms (3.4%) were harbored by patients who had presented with nonacute SAH. Sixty-five aneurysms (55%) were unruptured. Fifty-seven lesions (48.3%) were small with a small neck, 29 (24.6%) were small with a wide neck, 30 (25.4%) were large, and two (1.7%) were giant. All patients were followed up to obtain angiography and clinical outcome data. Technical complications occurred in six patients: two thromboembolic complications and four aneurysm perforations. Of these six patients, the status of two deteriorated because of aneurysm perforation and another two because of thrombus formation (morbidity 3.6%). There were five deaths--one due to rerupture after embolization. Angiography follow-up studies of 87 aneurysms were obtained. Seventy aneurysms demonstrated progressive occlusion or a stable neck (80.5%), and 17 had some degree of recanalization (19.5%). The aneurysms originally diagnosed as a neck remnant showed a 15% rate of recanalization. CONCLUSIONS: Matrix coils can be delivered into aneurysms with technical complications similar to those encountered using GDCs. Midterm anatomical outcomes to date have shown moderate improvement in the recanalization rate when compared with those realized using the GDC system. Because of the increased friction associated with the first-generation Matrix coil, the packing density in most aneurysms was less than that achieved with GDCs. Prolonged angiography follow-up evaluations are needed to document long-term efficacy.

Absorbable Implants↗

PubMed2006

Contribution of endovascular therapy to the management of poor-grade aneurysmal subarachnoid hemorrhage: Clinical and angiographic outcomes.

OBJECT: Treatment of patients presenting with poor-grade (Hunt and Hess Grade IV or V) subarachnoid hemorrhage (SAH) is controversial. Endovascular coil embolization has been considered a valuable therapeutic alternative to surgical clip placement for this kind of patient. The aim of the present study was to evaluate immediate and long-term angiographic and clinical outcomes in patients with poor-grade SAH treated by endovascular embolization. METHODS: One hundred eleven patients with Hunt and Hess Grade IV or V SAH were treated with endovascular embolization at the University of California at Los Angeles Medical Center between October 1990 and December 2004. Eighty patients harbored Grade IV hemorrhages and 31 patients had Grade V ones. Immediate and long-term anatomical and clinical outcomes were evaluated in all patients. Long-term clinical outcome assessments were based on follow-up data obtained over an average of 32 months posttherapy. Technical complications occurred in 15 patients (13.5%). Immediate complete aneurysm occlusion was observed in 51.4% of aneurysms. Angiographic, long-term follow-up review revealed aneurysm recanalization in 16.2% of cases. Thirty-nine patients (35.1%) demonstrated a favorable long-term clinical outcome. The overall mortality rate in this patient series was 32.4%. The mortality rate associated with vasospasm was significantly higher in patients with Grade IV SAHs than in those with Grade V hemorrhages. CONCLUSIONS: The results of this study demonstrate a valuable contribution of endovascular therapy of ruptured intracranial aneurysms in patients with Hunt and Hess Grade IV or V SAH. This technique was successful in decreasing repeated aneurysm rupture and in enabling aggressive medical management during the acute phase of SAH. This is particularly important in patients with Grade IV SAH because of their potential for obtaining higher physical and functional recoveries.

Aneurysm, Ruptured↗

PubMed2005

Endovascular management of dissecting vertebrobasilar artery aneurysms in patients presenting with acute subarachnoid hemorrhage.

OBJECT: The authors report on a series of 29 patients presenting with acute subarachnoid hemorrhage (SAH) related to the rupture of a vertebrobasilar dissecting aneurysm. Special attention was focused on embolization techniques and immediate and midterm anatomical and clinical outcomes. METHODS: Between March 1994 and January 2003, 29 patients presented with acute SAH caused by the rupture of a vertebrobasilar dissecting aneurysm. Eleven patients (37.9%) had Hunt and Hess Grade I SAH, four (13.8%) Grade II, six (20.7%) Grade III, five (17.2%) Grade IV, and three (10.3%) Grade V. Aneurysms were classified into five groups based on lesion location, and treatment courses were decided. All patients except two were treated by endovascular trapping of the aneurysm with concomitant occlusion of the involved vertebral artery (VA). No technical or clinical complication was observed in 28 patients (97%). Aneurysm perforation occurred during the procedure in one patient (3%). There was evidence of aneurysm recanalization in one patient. One patient with Hunt and Hess Grade IV SAH and two patients with Grade V SAH died. One patient died of respiratory infection 1 year after aneurysm trapping. One patient presented with a recurrent hemorrhage 1 month after treatment and died. Overall morbidity and mortality rates were 13.8 and 17.2%, respectively. CONCLUSIONS: Twenty-nine patients with acute SAH due to rupturing of vertebrobasilar dissecting aneurysms were treated using endovascular techniques. In most cases, endovascular trapping of the aneurysm and concomitant occlusion of the VA was technically and clinically successful.

Aneurysm, Ruptured↗

PubMed2005

Aneurysms of the posterior circulation: detection and treatment planning using volume-rendered three-dimensional helical computerized tomography angiography.

OBJECT: The aim of this study was to determine whether computerized tomography (CT) angiography could be used to identify and characterize aneurysms of the posterior circulation and guide optimal treatment selection, and how data obtained using this method compared with intraoperative findings. METHODS: Patients suspected of harboring brain aneurysms underwent CT angiography and digital subtraction (DS) angiography; the results were prospectively interpreted by blinded independent evaluators. All patients with posterior circulation aneurysms were consecutively enrolled in the study. After treatment, neurosurgeons and endovascular therapists evaluated the ability of CT and DS angiography to demonstrate features of the lesions important for triage between treatment options (Wilcoxon signed-rank test) and to allow for coil or clip preselection and complete treatment planning (McNemar test of proportions), while using intraoperative findings as the basis of truth. In 242 patients overall, CT angiography detected 38 aneurysms and two aneurysmal blisters in 32 patients. The sensitivity of CT angiography in revealing posterior circulation aneurysms was 100% compared with DS angiography, with no false-positive results. Furthermore, CT angiography was sufficient as the sole study at triage for 65% of the posterior circulation aneurysms (26 of 40 lesions; p < 0.001), including 62% of the complex lesions (p < 0.001), and permitted coil or clip preselection in 74% of treated cases (20 of 27 cases; p < 0.002). Results of CT angiography revealed information about mural calcification and intraluminal thrombus not available on DS angiography, which affected patient care. CONCLUSIONS: In this study population, CT angiography was comparable to DS angiography in the detection and characterization of aneurysms of the posterior circulation. Computerized tomography angiography was used successfully to triage patients between endovascular and neurosurgical treatment options in a significant proportion of cases and permitted treatment planning in more than 70% of treated cases.

Adult↗

PubMed2005

Angiographic evidence of aneurysm neck healing following endovascular treatment with bioactive coils.

A new angiographic finding in intracranial aneurysms embolized with Matrix coils is described. Two illustrative cases with a well-defined radiolucent separation between the coil mass and the parent artery are presented. To the best of our knowledge, this is the first report in humans of this finding. On the basis of prior histopathologic studies, this finding, which we call the "white-collar sign," may indicate the formation of a thick connective tissue barrier between aneurysm and artery that prevents any further aneurysmal filling.

Adolescent↗

PubMed2004

Intraaneurysmal flow visualization by using phase-contrast magnetic resonance imaging: feasibility study based on a geometrically realistic in vitro aneurysm model.

OBJECT: The aim of this study was to evaluate the feasibility of complex intraaneurysmal flow visualization with the currently available phase-contrast magnetic resonance (MR) imaging modality. METHODS: A geometrically realistic in vitro aneurysm model, in which detailed flow velocity analysis had already been conducted using laser Doppler velocimetry was used for this in vitro hemodynamic simulation, so that the results of phase-contrast velocity measurements could be compared with the previous reliable results. On a 1.5-tesla unit, three orthogonal components of velocity were obtained using a standard two-dimensional fast low-angle shot flow quantification sequence. Three-dimensional (3D) intraaneurysmal flow structures recorded during one cardiac cycle were depicted in one midsagittal and three axial cross-sectional planes with the aid of gray scale phase-contrast velocity maps. Isovelocity contour maps and secondary flow vectors were also created based on the phase-contrast velocity maps by using MATLAB software. The isovelocity contours in those three axial sections could demonstrate the shapes of inward and outward flow areas and their alternation over one cardiac cycle. The secondary flow vectors demonstrated twin vortices within the outward flow area adjacent to the boundary layer of inward and outward flow in all axial planes. CONCLUSIONS: The phase-contrast MR imaging method was able to depict the complex 3D intraaneurysmal flow structures in the in vitro aneurysm model. Detailed 3D intraaneurysmal flow information will be obtainable in vivo after improvements are made in spatial resolution, which is expected in the near future. The capability to visualize intraaneurysmal flow structures directly with the use of noninvasive MR imaging technology will have a positive impact on future clinical practice.

Hemodynamics↗

PubMed2004

Treatment of unruptured aneurysms with GDCs: clinical experience with 247 aneurysms.

BACKGROUND AND PURPOSE: The GDC system is a valuable therapeutic alternative to surgical treatment of intracranial aneurysms. We present our clinical experience with the GDC technique used to treat unruptured cerebral aneurysms. METHODS: This is a retrospective review of 217 patients with 247 unruptured intracranial aneurysms who underwent embolization with GDCs between August 1991 and June 2000. One hundred sixty-seven of the 217 were female patients. Patient age ranged from 13 to 83 years. In 118 patients, the aneurysms were found when unrelated non-neurologic conditions indicated angiography, CT angiography, or MR angiography (group 1). Fifty-one patients with mass effect symptoms comprised group 2, 12 patients with aneurysms associated with arteriovenous malformations or tumors of the brain comprised group 3, 17 patients with unruptured aneurysms treated during the chronic phase of subarachnoid hemorrhage (SAH) comprised group 4, and 19 patients treated during the acute phase of SAH due to another ruptured aneurysm comprised group 5. RESULTS: Angiographic results revealed complete occlusion in 138 of 247 aneurysms (55.9%), neck remnants in 92 (37.2%), and incomplete occlusion in three (1.2%). GDC embolization was attempted unsuccessfully in 14 aneurysms (5.7%). Of the 198 patients without acute SAH (groups 1-4), 186 (93.9%) of 198 remained neurologically unchanged. Eleven of the 217 patients (5.1%) experienced neurologic deterioration caused by immediate procedural complications. One patient died (0.5%) as a result of aneurysmal rupture during embolization. For asymptomatic patients and those treated after the chronic period of SAH, the mean hospitalization stay was 2.9 days. CONCLUSION: GDC technology constitutes safe treatment for unruptured aneurysms, with successful anatomic and clinical results and low complication rates achieved.

Adolescent↗

PubMed2003

In vitro measurement of fluid-induced wall shear stress in unruptured cerebral aneurysms harboring blebs.

BACKGROUND AND PURPOSE: Little attention has been focused on the role of fluid-induced wall shear stress in fully developed cerebral aneurysms. The purpose of this study is to evaluate the alternation and distribution of wall shear stress over 1 cardiac cycle in patients' aneurysms. METHODS: A middle cerebral artery aneurysm and a basilar tip aneurysm with localized outpouching (blebs) in their domes were selected for this study. With the use of a stereo lithography machine, geometrically realistic aneurysm models were created on the basis of 3-dimensional CT angiograms. In vitro shearing velocity measurement was conducted with the use of laser-Doppler velocimetry at multiple points on the aneurysmal wall to calculate the value of wall shear stress. The wall shear stress was documented at multiple points in the aneurysm inflow zone, dome, and outflow zone. RESULTS: Distribution of wall shear stress was not uniform in the aneurysm walls, and particular regions were exposed to relatively high wall shear stress. The wall shear stress changed dynamically throughout 1 cardiac cycle at the point where a high value of wall shear stress was noted. The blebs of both aneurysms were exposed to high wall shear stress. Unlike previous reports in which an ideal spherical aneurysm model was used, the aneurysm inflow zone was not exposed to high shear stress. CONCLUSIONS: In vitro aneurysm models based on the patients' angiograms allowed us to conduct a more realistic evaluation of wall shear stress in the aneurysms harboring blebs. These results provide us with further indications of the correlation of wall shear stress with the natural history of cerebral aneurysms.

Angiography↗

PubMed2003

Guglielmi detachable coil embolization of cerebral aneurysms: 11 years' experience.

OBJECT: The authors report on their 11 years' experience with embolization of cerebral aneurysms using Guglielmi Detachable Coil (GDC) technology and on the attendant anatomical and clinical outcomes. METHODS: Since December 1990, 818 patients harboring 916 aneurysms were treated with GDC embolization at University of California at Los Angeles Medical Center. For comparative purposes, the patients were divided into two groups: Group A included their initial 5 years' experience with 230 patients harboring 251 aneurysms and Group B included the later 6 years' experience with 588 patients harboring 665 aneurysms. Angiographically demonstrated complete occlusion was achieved in 55% of aneurysms and a neck remnant was displayed in 35.4% of lesions. Incomplete embolization was performed in 3.5% of aneurysms, and in 5% occlusion was attempted unsuccessfully. A comparison between the two groups revealed a higher complete embolization rate in patients in Group B compared with that in Group A patients (56.8 and 50.2%, respectively). The overall morbidity/mortality rate was 9.4%. Angiographic follow ups were obtained in 53.4% of cases of aneurysms, and recanalization was exhibited in 26.1% of aneurysms in Group A and 17.2% of those in Group B. The overall recanalization rate was 20.9%. Note that recanalization was related to the size of the dome and neck of the aneurysm. Overall incidence of delayed aneurysm rupture was 1.6%, a rate that improved in the past 5 years to 0.5%. Ten of 12 delayed ruptures occurred in large or giant aneurysms. CONCLUSIONS: The clinical and postembolization outcomes in patients treated with the GDC system have improved in the past 5 years. Aneurysm recanalization, however, is still a major limitation of current GDC therapy. Follow-up angiography is mandatory after GDC embolization of cerebral aneurysms. Further technical and device improvements are mandatory to overcome current GDC limitations.

Adult↗

PubMed2003

Three-dimensional blood flow analysis in a wide-necked internal carotid artery-ophthalmic artery aneurysm.

OBJECT: The aim of this study was to evaluate axial and secondary flow structures in a wide-necked internal carotid artery-ophthalmic artery aneurysm, one of the most common locations for endovascular coil placement. METHODS: A clear acrylic aneurysm model was manufactured from a three-dimensional computerized tomography angiogram. Intraaneurysm blood flow analysis was conducted using an acrylic aneurysm model together with laser Doppler velocimetry and particle imaging velocimetry. The maximal axial blood flow velocities in the inflow and outflow zones at the aneurysm orifice were noted at the peak systolic phase, measuring 46.8 and 24.9% of that in the parent artery, respectively. The mean size of the inflow zone during one cardiac cycle was 44.3 +/- 9.8% (range 35.6-58.7%) the size of the axial section at the aneurysm orifice. In the lower and upper planes of the aneurysm dome, the mean size of inward and outward flow areas were 43.3 +/- 6.7% and 43.8 +/- 6.8% the size of the axial cross-sectional plane, respectively. The axial flow velocity structures were dynamically altered throughout the cardiac cycle, particularly at the aneurysm orifice. The fastest secondary flow at the opening was also noted at the peak systolic and early diastolic phases. Axial blood flow velocity was slower in the upper axial plane of the aneurysm dome than in the lower one. Conversely, the secondary flow component was faster in the upper plane. CONCLUSIONS: The side-wall aneurysm in this study did not demonstrate a simple flow pattern as was previously seen in ideally shaped experimental aneurysms in vitro and in vivo. The flow patterns of inflow and outflow zones were very difficult to predict based on the limited flow information provided on standard digital subtraction angiography, even in an aneurysm with a relatively simple dome shape.

Aneurysm↗

PubMed2003

Combined endovascular treatment for both intracranial aneurysm and symptomatic vasospasm.

BACKGROUND AND PURPOSE: The best strategy for treatment of subarachnoid hemorrhage due to ruptured cerebral aneurysm is obliteration of the aneurysm as soon as possible. Early surgery is desirable if the patient does not develop severe vasospasm or is clinically stable. However, if the patient has already developed severe vasospasm on admission, surgery may carry the risk of increasing the severity. We evaluated the safety and effectiveness of combined Guglielmi detachable coil (GDC) embolization and angioplasty in a single session for the treatment of ruptured aneurysms associated with symptomatic vasospasm. METHODS: From January 1992 to January 2001, 12 consecutive patients with ruptured aneurysms associated with symptomatic vasospasm were treated. Patients were classified as Hunt and Hess grade 2 (n = 1), 3 (n = 6), 4 (n = 4), or 5 (n = 1) and Fisher CT group 2 (n = 1), 3 (n = 10), or 4 (n = 1). They underwent GDC aneurysm occlusion and balloon angioplasty (n = 6), intraarterial papaverine infusion (n = 2), or both (n = 4) in a single session. In nine patients, aneurysm coil occlusion was performed first. RESULTS: Complete GDC occlusion was achieved in eight patients, a small neck remnant persisted in three, and embolization was incomplete in one patient. In all patients, angiographic improvement of vasospasm was obtained. In one patient, a thromboembolic complication occurred and was treated with urokinase. Clinical outcomes at discharge were good recovery in six, moderate disability in two, severe disability in three, or death in one. CONCLUSION: Endovascular treatment can be the first therapeutic option for ruptured aneurysms associated with severe vasospasm on admission. It offers some advantages over surgery in this setting, but these are balanced by the risk of thromboembolism.

Adult↗

PubMed2002

Management of intraprocedural arterial thrombus in cerebral aneurysm embolization with abciximab: technical case report.

OBJECTIVE AND IMPORTANCE: Thromboembolic complications after cerebral aneurysm treatment with Guglielmi detachable coils (Boston Scientific/Target, Fremont, CA) are not infrequent; in a University of California, Los Angeles institutional review of 720 treated aneurysms, thromboembolic complications occurred in 2.5% of cases. The development of intraluminal thrombus during the embolization procedure, however, may be diagnosed promptly and treated effectively with appropriate therapy. This report describes the use of intravenously administered abciximab for the treatment of intraprocedural arterial thrombus encountered during the coil embolization of a recently ruptured anterior communicating artery aneurysm. CLINICAL PRESENTATION: A 45-year-old man presented with severe headache 12 days before transfer to our institution. He had no neurological deficits at admission. Previous computed tomography of the brain demonstrated subarachnoid hemorrhage, and magnetic resonance angiography from the other institution demonstrated a 4-mm anterior communicating artery aneurysm. INTERVENTION: The patient underwent Guglielmi detachable coil embolization of the aneurysm under systemic heparinization. During the embolization, however, a thrombus developed in the proximal left A2 segment. The patient was given an intravenous infusion (20 mg) of abciximab for 10 minutes, and within 15 minutes dissolution of the thrombus was observed with no angiographic evidence of distal emboli. After reversal of general anesthesia, the patient exhibited minimal right leg weakness, which resolved within 1 hour. CONCLUSION: Abciximab may be a useful adjunct for endovascular treatment of patients with cerebral aneurysms in whom intraprocedural arterial thrombus is encountered.

Abciximab↗

PubMed2002

Multimodal quantitation of the effects of endovascular therapy for vasospasm on cerebral blood flow, transcranial doppler ultrasonographic velocities, and cerebral artery diameters.

OBJECTIVE: The goal of this study was to quantify the effects of endovascular therapy on vasospastic cerebral vessels. METHODS: We reviewed the medical records for 387 patients with ruptured intracranial aneurysms who were treated at a single institution (University of California, Los Angeles) between May 1, 1993, and March 31, 2001. Patients who developed cerebral vasospasm and underwent cerebral arteriographic, transcranial Doppler ultrasonographic, and cerebral blood flow (CBF) studies before and after endovascular therapy for cerebral arterial spasm (vasospasm) were included in this study. RESULTS: Forty-five patients fulfilled the aforementioned criteria and were treated with either papaverine infusion, papaverine infusion with angioplasty, or angioplasty alone. After balloon angioplasty (12 patients), CBF increased from 27.8 +/- 2.8 ml/100 g/min to 28.4 +/- 3.0 ml/100 g/min (P = 0.87); the middle cerebral artery blood flow velocity was 1 57.6 +/- 9.4 cm/s and decreased to 76.3 +/- 9.3 cm/s (P < 0.05), with a mean increase in cerebral artery diameters of 24.4%. Papaverine infusion (20 patients) transiently increased the CBF from 27.5 +/- 2.1 ml/100 g/min to 38.7 +/- 2.8 ml/100 g/min (P < 0.05) and decreased the middle cerebral artery blood flow velocity from 109.9 +/- 9.1 cm/s to 82.8 +/- 8.6 cm/s (P < 0.05). There was a mean increase in vessel diameters of 30.1% after papaverine infusion. Combined treatment (13 patients) significantly increased the CBF from 33.3 +/- 3.2 ml/100 g/min to 41.7 +/- 2.8 ml/100 g/min (P< 0.05) and decreased the transcranial Doppler velocities from 148.9 +/- 12.7 cm/s to 111.4 +/- 10.6 cm/s (P < 0.05), with a mean increase in vessel diameters of 42.2%. CONCLUSION: Balloon angioplasty increased proximal vessel diameters, whereas papaverine treatment effectively dilated distal cerebral vessels. In our small series, we observed no correlation between early clinical improvement or clinical outcomes and any of our quantitative or physiological data (CBF, transcranial Doppler velocities, or vessel diameters).

Adult↗

PubMed2002

Cellular responses of bioabsorbable polymeric material and Guglielmi detachable coil in experimental aneurysms.

BACKGROUND AND PURPOSE: Acceleration of healing mechanisms is a promising approach to improve current limitations of endovascular aneurysm therapy with the use of platinum coils. We evaluated a new endovascular therapeutic, bioabsorbable polymeric material (BPM), which may promote cellular reaction in the aneurysms. METHODS: Four different concentrations of lactide/glycolic acid copolymer [poly(D-L-lactic-co-glycolic acid)] (PLGA), 85/15, 75/25, 65/35, and 50/50, were used as BPMs. Sixteen experimental aneurysms were created in 8 swine. Eight-millimeter-long spiral-shaped BPMs were surgically implanted in the aneurysms without tight packing (n=3 for each BPM). Guglielmi detachable coils (GDCs) were used as control (n=4). The animals were killed 14 days after embolization, and angiographic, histological, and immunohistochemical analyses were performed. RESULTS: Despite loose packing of aneurysms with BPMs, faster BPMs such as 50/50 or 65/35 PLGA demonstrated more mature collagen formation and fibrosis in the sac and neck of the aneurysm. One aneurysm treated with 65/35 PLGA, 1 treated with 75/25 PLGA, and all 3 treated with 85/15 PLGA showed a neck remnant on angiography. There was a linear relationship between collagen levels and polymer degradation properties (r=-0.9513). CONCLUSIONS: This preliminary animal study indicates that acceleration of aneurysm healing with the use of BPM is feasible. This concept can be applied to decrease and perhaps prevent aneurysmal recanalization after endovascular treatment of cerebral aneurysms.

Absorbable Implants↗

PubMed2002

Adult pial arteriovenous fistula and superior sagittal sinus stenosis: angiographic evidence for high-flow venopathy at an atypical location. Case report.

The authors present the case of a 69-year-old man who suffered from bilateral cortical venous hypertension due to a brain pial arteriovenous malformation (AVM) with a high-flow fistula. The AVM became complicated by the development of a high-grade stenosis of the posterior superior sagittal sinus (SSS). A comparison of cerebral angiograms obtained at different times revealed that the severe SSS stenosis had developed within a 5-year period and was located distal to the nidus of the left parietal AVM nidus, away from the entrance of the dominant superior superficial cortical draining vein into the SSS. The high-flow fistula was occluded with detachable coils and the AVM nidus was further embolized with acrylic. The SSS stenosis was mechanically dilated by means of balloon angioplasty and stent placement. This case provides angiographic evidence to support the hypothesis that a pial arteriovenous fistula in an adult can cause high-flow occlusive venopathy in a major sinus within a relatively short time and that this acquired high-flow occlusive venopathy can develop at an atypical location distant from the nidus of the AVM.

Aged↗

PubMed2002

Three-dimensional helical computerized tomography angiography in the diagnosis, characterization, and management of middle cerebral artery aneurysms: comparison with conventional angiography and intraoperative findings.

OBJECT: Middle cerebral artery (MCA) aneurysms can be difficult to detect and characterize. The authors describe the utility and impact of helical computerized tomography (CT) angiography for the evaluation of aneurysms in this location, and compare this modality with digital subtraction (DS) angiography and intraoperative findings. METHODS: Two hundred fifty-one patients with suspected cerebral aneurysms underwent CT angiography. Two-dimensional multiplanar reformatted images and three-dimensional CT angiograms were examined by two independent readers in a blinded fashion. Results were compared with findings on DS angiograms to determine the relative efficacy of these modalities in the detection and characterization of aneurysms. Questionnaires completed by neurosurgeons and endovascular therapists were used to determine the impact of CT angiograms on aneurysm management. Twenty-eight patients harboring 31 MCA aneurysms and 26 patients without aneurysms were identified using CT angiography. The sensitivity of CT angiography and DS angiography for MCA aneurysms was 97%; both techniques showed 100% specificity. In 76% of evaluations, the CT angiography studies provided information not available on DS angiography examinations. For the characterization of aneurysms, CT angiography was rated superior (72%) or equal (20%) to DS angiography in 92% of cases evaluated (p < 0.001). Computerized tomography angiography was evaluated as the only study needed for patient triage in 82% of cases (p < 0.001), and as the only study needed for treatment planning in 89% of surgically treated (p < 0.001) and in 63% of endovascularly treated cases (p < 0.001). The information acquired on CT angiograms changed the initial treatment plan in 24 (67%) of these 36 complex lesions (p < 0.01). The aneurysm appearance intraoperatively was identical or nearly identical to that seen on CT angiograms in 17 (89%) of 19 of the surgically treated cases. CONCLUSIONS: Computerized tomography angiography has unique advantages over DS angiography and is a viable alternative to the latter modality in the diagnosis, triage, and treatment planning in patients with MCA aneurysms.

Adult↗