acetylcellulose and Intracranial-Aneurysm

Electrolytic detachable coils (EDC) have been the main embolic materials for intracranial aneurysms. Liquid aneurysmal embolic materials represented by cellulose acetate polymer (CAP) are still in controversy. In this research, the embolization results and pathological reactions after embolization of canine aneurysmal models with EDC or CAP were observed and compared.. The canine aneurysmal models constructed by anastomosis of venous pouches were randomly grouped. The aneurysms were respectively occluded with CAP and electrolytic detachable coils that was named by Wu electrolytic detachable coil (WEDC) and made by us. Angiogram follow-ups were performed at 24-hour, 2-week, and 2-month after embolization. The occluded aneurysms were dissected in each stage for light microscopic, electron microscopic, and histochemical research.. The effect of embolization was significantly better with WEDC than that with CAP (chi2 = 5. 56, P < 0.05). Post-embolized complications such as aneurysm rupture and stenosis of parent arteries could only be found in CAP group. Pathological research showed that CAP mass could packed the aneurysms more densely than coils. Acute chemical damage of aneurysmal wall and inflammatory cell infiltration was prominently found in early stage after CAP-embolization. Organization of thrombus inside aneurysms and formation of endothelial tissue over the orifices of aneurysmal necks could be found in both groups 2 months after embolization. But parts of coils might be exposed outside endothelial layer.. EDC are still the most safe, efficient, and reliable instruments to embolize aneurysm. CAP should be improved further to solve the problem of strong chemical corrosion and difficulty in control before it is widely used.

Topics: Animals; Biocompatible Materials; Cellulose; Dogs; Embolization, Therapeutic; Female; Follow-Up Studies; Intracranial Aneurysm; Male; Random Allocation; Tungsten

Endovascular treatments for aneurysms are being used more frequently in patients in the absence of a large body of information on their histopathological effects. This study determined the efficacy and histopathological effects of treatment of experimental aneurysms with Guglielmi detachable coils (GDC) or cellulose acetate polymer (CAP).. Fourteen dogs had 13 terminal and 30 sidewall aneurysms created with venous pouches sutured to the cervical carotid arteries. Two weeks later, dogs had angiography followed by randomization to no treatment (n=2) or to aneurysm occlusion with GDC (n=4) or CAP (n=6). Two months later, angiography was repeated, animals were killed, and aneurysms were excised, fixed, photographed, and examined by light and electron microscopy.. Two dogs were excluded because of common carotid artery occlusion at 2-week angiography. There were 11 terminal and 16 sidewall aneurysms available for treatment. The rate of spontaneous thrombosis of untreated aneurysms was 0% (0/5). Treatment with GDC showed complete terminal and sidewall aneurysm obliteration rates of 33% (1/3) and 80% (4/5), respectively. Greater than 90% occlusion occurred in the remaining cases. There were no parent or branch artery occlusions. Treatment with CAP showed complete terminal and sidewall aneurysm obliteration rates of 20% (1/5) and 0% (0/5), respectively, and incomplete sidewall aneurysm obliteration in 1 of 5 cases. Aneurysms reformed at 2 months in 2 of 5 terminal and 1 of 5 sidewall cases. There were parent or branch artery occlusions with CAP in 2 and 4 cases, respectively. The rate of aneurysm occlusion was significantly lower and the rate of arterial occlusion significantly higher with CAP than with GDC (P<.05). Histopathology showed complete endothelialization across the orifice of the aneurysm successfully treated with CAP, whereas aneurysms treated with GDC were significantly more likely to show fresh or organizing thrombus without complete endothelialization (P<.05).. It is concluded that both treatments have limitations. Complete packing of aneurysms with GDC obliterates the aneurysm, but endothelialization does not always occur within 2 months. There are substantial problems with CAP. It is thrombogenic and carries a higher risk of causing arterial thrombosis. Even if an aneurysm is successfully obliterated initially with CAP, the CAP may disappear, leaving the aneurysm completely untreated.

Topics: Animals; Biocompatible Materials; Cellulose; Cerebral Angiography; Cerebral Arteries; Dogs; Embolization, Therapeutic; Intracranial Aneurysm; Intracranial Embolism and Thrombosis; Random Allocation

Experimental aneurysms were created using a microsurgical technique to produce anastomosed venous pouches in the bilateral common carotid arteries of 12 dogs. The 24 aneurysms were then thrombosed via an endovascular approach with injection of a cellulose acetate polymer (CAP) solution that the authors have developed for use as a liquid thrombotic material. Angiography performed 1 to 4 weeks after CAP injection revealed complete thrombosis of the aneurysm with patency of the parent artery in 16 aneurysms. Histological analysis disclosed that the aneurysmal orifice in these cases was completely covered with newly formed endothelial cells 2 weeks after CAP thrombosis. Three other aneurysms exhibited parent artery occlusion caused by protrusion of the CAP mass through the aneurysmal orifice into the parent artery; this was thought to be caused by over-injection of the CAP solution. Histological analysis of the remaining five aneurysms, initially shown to have incomplete occlusion, revealed that they each possessed a residual neck that was partially covered with endothelial cells. No rupture of the aneurysms or migration of CAP into the distal arteries was observed. These results suggest that using an endovascular approach, direct thrombosis of cerebral aneurysms with CAP is safe and effective. This technique may prove to be an alternative treatment for such aneurysms. However, there is a potential risk of regrowth or rupture of aneurysms that retain a residual neck and long-term follow-up studies will be required to evaluate this issue.

Topics: Animals; Cellulose; Cerebral Angiography; Dogs; Embolization, Therapeutic; Endothelium, Vascular; Evaluation Studies as Topic; Follow-Up Studies; Intracranial Aneurysm; Polymers; Vascular Patency; von Willebrand Factor

Twelve patients with Hunt and Hess neurological Grades III to V underwent thrombosis of aneurysms using cellulose acetate polymer within 23 hours of aneurysm rupture. On computerized tomography (CT), nine of these patients had difuse or localized thick subarachnoid blood clots, two had diffuse thin clots and one had intraventricular clots. Immediately after thrombosis, all patients were administered tissue plasminogen activator (TPA) through spinal or ventricular catheters. The pressure of the lumbar cerebrospinal fluid was maintained at 100 to 150 mm H2O. The TPA was given as multiple injections of 2 mg on Day 0 and 1 to 2 mg on the following 1 to 2 days. In two patients the second injection of TPA was not given because of severe brain damage resulting from the initial subarachnoid hemorrhage. Ten patients showed complete clearance of the cisternal clot on CT within 72 hours after thrombosis. Seven partially thrombosed aneurysms and five multiple aneurysms were clipped during delayed surgery. Only one patient experienced mild vasospasm as shown on the follow-up angiogram. Eight patients improved clinically and had a good recovery, two had severe disability, and two died. Urgent thrombosis of a ruptured aneurysm followed by immediate postthrombotic administration of TPA may be a safe and reasonable means of preventing vasospasm and improving patient outcome.

Topics: Aged; Aged, 80 and over; Aneurysm, Ruptured; Cellulose; Cerebral Angiography; Drainage; Female; Follow-Up Studies; Humans; Hydrocephalus; Intracranial Aneurysm; Ischemic Attack, Transient; Male; Microsurgery; Middle Aged; Recurrence; Subarachnoid Hemorrhage; Thrombolytic Therapy; Tissue Plasminogen Activator; Tomography, X-Ray Computed; Treatment Outcome

Cellulose acetate polymer solution is a liquid thrombotic material that hardens into the shape of an aneurysm into which it is injected. Therapy using this solution is a rapid technique that helps prevent the rupture of aneurysms, especially those that extravasate contrast material during angiography in the acute stage of subarachnoid hemorrhage. Using this polymer solution and an endovascular technique, we treated two patients who had aneurysms of the basilar and anterior communicating arteries with extravasation of contrast material during angiography a few hours after the initial subarachnoid hemorrhage. In one patient with an aneurysm of the anterior communicating artery, the aneurysm's wall was perforated with the catheter during neurointerventional procedures. In both patients, postoperative angiograms demonstrated obliteration of the aneurysmal dome, including the site of extravasation or perforation. The parent artery and surrounding perforating branches were preserved. Although we do not advocate aggressive therapy for patients who bleed during angiography, we pursued this therapy in these two patients because of the opportunity to introduce cellulose acetate polymer in an attempt to preserve the patients' lives. Unfortunately, both patients died. Histopathological studies performed at the time of autopsy demonstrated that the luminal surface of cellulose acetate polymer was covered with thrombus by 6 days after cellulose acetate polymer thrombosis. By 10 days, the thrombus had a prominent fibrin network, a concentrated plasma component, and few fibrocytes adhering to its luminal surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Aneurysm, Ruptured; Angiography, Digital Subtraction; Basilar Artery; Cellulose; Cerebral Angiography; Cerebral Arteries; Embolization, Therapeutic; Emergencies; Extravasation of Diagnostic and Therapeutic Materials; Fatal Outcome; Female; Humans; Intracranial Aneurysm; Male; Polymers; Subarachnoid Hemorrhage

Topics: Animals; Cellulose; Dimethyl Sulfoxide; Dogs; Embolization, Therapeutic; Injections, Intra-Arterial; Intracranial Aneurysm; Renal Artery

The authors report the treatment of seven intracranial aneurysms in six patients with direct infusion of cellulose acetate polymer solution, a new liquid thrombotic material. These aneurysms were considered inoperable because of their size or location, or because of the patient's neurological condition. This material avoids the difficulties associated with balloon occlusion, and completely fills even irregularly shaped aneurysms. Cellulose acetate polymer solution hardens in about 5 minutes and remains solid once inside the aneurysm. Because this technique is less invasive than surgery, it can be used for high-risk patients in the acute stage of subarachnoid hemorrhage. Transient motor aphasia occurred in one patient. A small residual neck, which caused rebleeding 3 months after the treatment, remained in another patient. This article describes the new material, the procedure for direct thrombosis, and preliminary clinical results.

Topics: Adult; Cellulose; Cerebral Angiography; Embolization, Therapeutic; Female; Follow-Up Studies; Humans; Intracranial Aneurysm; Male; Middle Aged; Polymers; Recurrence; Rupture, Spontaneous; Subarachnoid Hemorrhage