Showing papers by "Cameron G. McDougall published in 2003"

A reappraisal of angioplasty and stenting for the treatment of vertebral origin stenosis.

Abstract: Objective To assess the rate of restenosis after vertebral origin angioplasty and stenting (VOAS). Methods We reviewed the records of 33 patients (24 men, 9 women; age range, 49-81 yr; mean, 64.5 yr) who underwent VOAS during a period of 5 years and followed each for the development of adverse sequelae through a prospectively maintained database. A neuroradiologist not involved in the stenting procedures assessed original and follow-up angiograms for evidence of restenosis. Restenosis was quantified as insignificant (0-24%), mild (25-49%), moderate (50-74%), or severe (75-100%). Results Of the 33 patients, 30 presented with transient ischemic attacks or stroke. Most (31 of 33 patients) manifested other brachiocephalic stenoses, including 27 patients with occlusion, hypoplasia, or stenosis of the contralateral vertebral artery. Angiographic follow-up (mean, 16.2 mo) was obtained in 30 patients (2 patients died before follow-up, and 1 refused). Restenosis was mild in seven patients, moderate in eight, and severe in five. The combined rate of moderate-to-severe restenosis was 43.3%. No complications resulted in permanent morbidity. One patient died as a result of a stroke in a different vascular distribution 4 months after VOAS. Another patient died as a result of basilar thrombosis in which emergent stenting had been undertaken in an effort to perform thrombolysis. Conclusion Despite a technical success rate of 97% and a low incidence of complications, VOAS is associated with a high rate of moderate-to-severe restenosis.

Evolution of the management of tentorial dural arteriovenous malformations.

Abstract: OBJECTIVE Tentorial dural arteriovenous malformations (DAVMs) are uncommon lesions associated with an aggressive natural history. Controversy exists regarding their optimal treatment. We present a single-institution series of tentorial DAVMs treated during a 12-year period, address the current controversies, and present the rationale for our current therapeutic strategy. METHODS Twenty-two patients with tentorial DAVMs were treated between 1988 and 2000. Treatment consisted of transarterial or transvenous embolization, surgical resection, disconnection of venous drainage, or a combination of these therapies. The clinical presentations, radiological features, treatment strategies, and results were studied. RESULTS Eighteen patients (82%) presented with intracranial hemorrhage or progressive neurological deficits. Retrograde leptomeningeal venous drainage was documented in 22 cases (100%), classifying the lesions as Borden Type III. Angiographic follow-up monitoring was performed for 0 to 120 months and clinical follow-up monitoring for 1 to 120 months. Posttreatment angiography demonstrated obliteration in 22 cases (100%). Two patients experienced neurological decline after endovascular treatment and died. All of the 20 surviving patients exhibited clinical improvement; there were no episodes of rehemorrhage or new neurological deficits. Outcomes were excellent in 17 cases (77%), good in 2 cases (9%), and fair in 1 case (5%), and there were 2 deaths (9%). CONCLUSION Tentorial DAVMs are aggressive lesions that require prompt total angiographic obliteration. Disconnection of the venous drainage from the fistula may be accomplished with transarterial embolization to the venous side, transvenous embolization, or surgical disconnection of the fistula. We think that extensive nidal resections carry more risk and are unnecessary. We do not think there is a role for stereotactic radiosurgery in the treatment of these lesions.

Recurrence of a vertebral artery dissecting pseudoaneurysm after successful stent-supported coil embolization: case report.

Abstract: Objective and importance Dissecting aneurysms of the intracranial vertebral artery are increasingly recognized as a cause of subarachnoid hemorrhage. We present a case involving technical success of the stent-supported coil embolization but with recurrence of the dissecting pseudoaneurysm of the intracranial vertebral artery. The implications for the endovascular management of ruptured dissecting pseudoaneurysms of the intracranial vertebral artery are discussed. Clinical presentation A 36-year-old man with a remote history of head injury had recovered functionally to the point of independent living. He experienced the spontaneous onset of severe head and neck pain, which progressed rapidly to obtundation. A computed tomographic scan of the head revealed subarachnoid hemorrhage centered in the posterior fossa. The patient underwent cerebral angiography, which revealed dilation of the distal left vertebral artery consistent with a dissecting pseudoaneurysm. Intervention Transfemoral access was achieved under general anesthesia, and two overlapping stents (3 mm in diameter and 14 mm long) were placed to cover the entire dissected segment. Follow-up angiography of the left vertebral artery showed the placement of the stents across the neck of the aneurysm; coil placement was satisfactory, with no residual aneurysm filling. Approximately 6 weeks after the patient's initial presentation, he developed the sudden onset of severe neck pain. A computed tomographic scan showed no subarachnoid hemorrhage, but computed tomographic angiography revealed that the previously treated left vertebral artery aneurysm had recurred. Angiography confirmed a recurrent pseudoaneurysm around the previously placed Guglielmi detachable coils. A test balloon occlusion was performed for 30 minutes. The patient's neurological examination was stable throughout the test occlusion period. Guglielmi detachable coil embolization of the left vertebral artery was then performed, sacrificing the artery at the level of the dissection. After the procedure was completed, no new neurological deficits occurred. On the second day after the procedure, the patient was discharged from the hospital. He was alert, oriented, and able to walk. Conclusion We appreciate the value of preserving a parent vessel when a dissecting pseudoaneurysm of the intracranial vertebral artery ruptures in patients with inadequate collateral blood flow, in patients with disease involving the contralateral vertebral artery, or in patients with both. However, our case represents a cautionary note that patients treated in this fashion require close clinical follow-up. We suggest that parent vessel occlusion be considered the first option for treatment in patients who will tolerate sacrifice of the parent vessel along its diseased segment. In the future, covered stent technology may resolve this dilemma for many of these patients.

Percutaneous intracranial stent placement for aneurysms.

Abstract: Object. Intracranial stent placement combined with coil embolization is an emerging procedure for the treatment of intracranial aneurysms. The authors report their results using intracranial stents for the treatment of intracranial aneurysms. Methods. A prospectively maintained database was reviewed to identify all patients with intracranial aneurysms that were treated with intracranial stents. Ten lesions, including eight broad-based aneurysms and two dissecting aneurysms, were treated in 10 patients. Four lesions were located in the cavernous segment of the internal carotid artery, two at the vertebrobasilar junction, two at the basilar trunk, one at the basilar apex, and one in the intracranial vertebral artery. Attempts were made to place stents in 13 patients, but in three the stents could not be delivered. Altogether, intracranial stents were placed in 10 patients for 10 lesions. Results that were determined to be satisfactory angiographically were achieved in all 10 lesions. Two patients suffered p...

Reversal of blindness after transvenous embolization of a carotid-cavernous fistula: case report.

Abstract: Objective and importance Reversal of blindness after the endovascular treatment of a carotid-cavernous fistula (CCF) is exceedingly rare. It has been reported only once in a patient with a direct CCF. We report the first such case in a patient with an indirect CCF. Defining patients whose vision may recover is critical in coordinating the timing of therapy. Mechanisms of reversible visual loss in CCFs are discussed with the intent of elucidating the patients who compose this subgroup. Clinical presentation A 65-year-old man had a 1-week history of blindness, chemosis, and proptosis of the right eye. Ophthalmoscopy was compromised by diffuse choroidal effusion and corneal edema that obscured visualization of the patient's retina. Intervention Transvenous embolization through retrograde catheterization of the superior ophthalmic vein allowed complete coil occlusion of the lesion. The patient's visual loss improved rapidly, returning to normal within 50 days. Conclusion Although CCFs frequently are associated with permanent visual loss, a subset of patients demonstrates reversible ocular findings. If the retina of a patient with a CCF seems normal or is obscured, the potential for visual recovery, even from blindness, should prompt emergent treatment.

Scalp arteriovenous malformation draining into the superior sagittal sinus associated with an intracranial arteriovenous malformation: just a coincidence? Case report.

Abstract: Objective and importance Recent experimental and clinical evidence suggests that hemodynamic changes in the venous system can induce the formation of new arteriovenous malformations (AVMs). In a rat model, increased venous pressure induces the formation of soft tissue and dural AVMs. We report a clinical observation that may support these data. Clinical presentation A 4-year-old boy with a midline scalp AVM draining into the superior sagittal sinus had an associated intracranial/parenchymal AVM. The cerebral AVM increased venous pressure in the superior sagittal sinus as revealed by angiography. Intervention The scalp AVM was resected, and the intracranial AVM was treated by use of the gamma knife. Conclusion On the basis of reported experimental data and the morphological and hemodynamic characteristics in this patient's two lesions, we suggest that the scalp AVM might have been induced by hypertension in the superior sagittal sinus. This clinical observation supports the notion suggested by experimental studies that hemodynamic changes can induce the formation of associated AVMs.

Cerebral dural arteriovenous fistula.

Abstract: Management of cerebral dural arteriovenous fistulae (DAVFs) has long been a subject of debate. With the advent of liquid adhesive embolics and coils, endovascular treatment has been the procedure of choice for most DAVFs. Nonetheless, this modality alone may not completely cure some fistulae. Surgical intervention is warranted in such cases. Therefore, a multidisciplinary approach to cerebral DAVFs that involves combined endovascular and neurosurgical treatment will improve the efficacy of treatment4.

Chronic assessment of ALGEL/spl reg/ for endovascular embolization of an arteriovenous malformation model in swine

Abstract: We sought to assess the stability of ALGEL (Neural Intervention Technologies, Ann Arbor, MI) as an embolic agent in an animal model of a cerebral arteriovenous malformation (AVM). Swine cerebral AVM models were used to test the mechanical stability and biocompatibility of ALGEL as an occlusive agent in a pre-clinical study for up to 6 month survival. The swine cerebral AVM model included a carotid-jugular anastomosis to increase flow to the rete mirabile (RM), thereby simulating the pressure gradient and shunted blood flow of an AVM. ALGEL and the reactive component, calcium chloride, were injected through double-lumen microcatheters to form an RM occlusion in chronic swine models. ALGEL injection blocked blood flow to the inferior portion of the RM, but left flow open to the superior portion of the RM and the circle of Willis. One- and six-month survival results showed that the ALGEL remained a stable occlusive material. Histology results showed a minor bioactive response and encapsulation of ALGEL, thereby increasing the stability and effective occlusion of the embolization material. ALGEL appears to initiate a bioactive response to maintain a stable and long-term endovascular occlusion.