Biomedical subjects

Alan S Boulos

Publications and source records attributed to Alan S Boulos.

25 records · Page 2Linked to original sources

PubMed2002

Brainstem infarction after delayed thrombosis of a stented vertebral artery fusiform aneurysm: case report.

OBJECTIVE AND IMPORTANCE: Recent technological advances have provided clinicians with stents that can be navigated throughout the tortuous proximal vessels of the posterior intracranial circulation. There have been few reports of fusiform and wide-necked aneurysms treated with stents. Of the known risks involved in stent placement in the intracranial circulation, delayed stent thrombosis has not been well described. CLINICAL PRESENTATION: A 34-year-old man who experienced the sudden onset of a severe headache with increasing lethargy was found on computed tomographic imaging to have a subarachnoid hemorrhage. Angiography revealed a left vertebral artery fusiform aneurysm that incorporated the posteroinferior cerebellar artery origin. INTERVENTION: A low-porosity Magic Wallstent (Boston Scientific, Natick, MA) was placed in the left vertebral artery across the aneurysm and the origin of the posteroinferior cerebellar artery. Angiography performed 9 days later revealed significant reduction in filling of the aneurysm. The patient returned 3 months after stent placement with severe neurological deterioration from a brainstem infarction caused by complete thrombotic occlusion of the left vertebral artery at the stented segment of the vessel. CONCLUSION: Stenting of fusiform aneurysms has provided an alternative to surgical clipping or parent vessel reconstruction. With the increasing frequency of intracranial stent placement for various cerebrovascular disease entities, we must become aware of potential complications associated with these procedures. Such awareness may influence decision-making processes regarding treatment and follow-up care.

Adult↗

PubMed2002

Aggressive mechanical clot disruption and low-dose intra-arterial third-generation thrombolytic agent for ischemic stroke: a prospective study.

OBJECTIVE: We prospectively evaluated the safety and effectiveness of aggressive mechanical disruption of clot in conjunction with intra-arterial administration of a low-dose third-generation thrombolytic agent (reteplase) to treat ischemic stroke in patients who were considered poor candidates for intravenous alteplase therapy or who failed to improve after intravenous thrombolysis. Mechanical clot disruption was used if low-dose pharmacological thrombolysis was ineffective. This strategy was adopted to increase the recanalization rate without increasing the risk of intracerebral hemorrhage. METHODS: Patients were considered poor candidates for intravenous therapy because of severity of neurological deficits, interval from symptom onset to presentation of at least 3 hours, or recent major surgery. We administered a maximum total dose of 4 U of reteplase intra-arterially in 1-U increments via superselective catheterization. After the initial doses were administered, we performed mechanical angioplasty (for proximal occlusion) or snare manipulation (for distal occlusion) at the occlusion site if recanalization had not occurred. The remaining doses of thrombolytics were subsequently administered if required for further recanalization. Angiographic responses were graded using modified Thrombolysis in Myocardial Infarction (TIMI) criteria. Clinical evaluations were performed before and 24 hours, 7 to 10 days, and 1 to 3 months after treatment. RESULTS: Nineteen consecutive patients were treated (mean age, 64.3 +/- 16.2 yr; 10 were men). Initial National Institutes of Health Stroke Scale scores ranged from 11 to 42. Time from onset to treatment ranged from 1 to 9 hours. Occlusion sites were in the following arteries: cervical internal carotid (n = 7), intracranial internal carotid (n = 1), middle cerebral (n = 9), and basilar (n = 2). Of the 19 patients, thrombolysis alone was used in 5 patients, angioplasty was performed in 11 patients, and snare maneuvers were used in 5 patients. Complete restoration of blood flow (modified TIMI Grade 4) was observed in 12 patients, near-complete restoration of flow (modified TIMI Grade 3) in 4 patients, minimal response (modified TIMI Grade 1) in 1 patient, and no response in 2 patients (modified TIMI Grade 0). Neurological improvement at 24 hours (decline of at least 4 points in National Institutes of Health Stroke Scale score) was observed in seven patients. Five other patients experienced further improvement in National Institutes of Health Stroke Scale score at 7 to 10 days. No vessel rupture, dissection, or symptomatic intracranial hemorrhages were observed. At the time of follow-up evaluation, 7 of 19 patients were functionally independent. CONCLUSION: A high rate of recanalization and clinical improvement can be observed in patients with ischemic stroke using low-dose thrombolytic agents with adjunctive mechanical disruption of clot. Moreover, this strategy may reduce the risk of intracerebral hemorrhage observed with thrombolytics.

Adult↗

PubMed2002

Endovascular aneurysm treatment: a proven therapy.

Endovascular treatment of aneurysms is an evolving technique. Endovascular techniques for the treatment of aneurysms have been available for 10 years. During this time, we have seen major advances and improvements in our ability to embolize aneurysms via an endoluminal approach. We have continued to modify our techniques and selection of patients who would most benefit from this approach. This article summarizes the current literature and attempts to develop a management strategy toward improving patient outcome by optimizing the choice between endovascular and surgical treatment modalities.

Aortic Dissection↗

PubMed2002

Stent-assisted endoluminal revascularization for the treatment of intracranial atherosclerotic disease.

Since the inception of intravascular stents in the 1960s, marked technological advancements have yielded stents that can be navigated through tortuous cerebral vessels. Numerous applications for intracranial stenting are being developed at an exciting pace. One such application that has shown promise in several small series is the use of stents for endoluminal revascularization of severe intracranial stenosis that is refractory to medical therapy. Prior to the introduction of endovascular approaches for this condition, complex bypass procedures were often necessary to restore adequate blood flow to hypoperfused parenchyma. In the following article, we review endovascular techniques for stenting of intracranial atherosclerotic disease. Patient selection, vascular access, medical management, and future directions are discussed.

Angioplasty↗

PubMed2002

Staged stent-assisted angioplasty for symptomatic intracranial vertebrobasilar artery stenosis.

OBJECT: Medically refractory symptomatic vertebrobasilar atherosclerotic disease has a poor prognosis. Studies have shown that longer (> or = 10 mm), eccentric, high-grade (> 70%) stenoses portend increased procedure-related morbidity. The authors reviewed their experience to determine whether a staged procedure consisting of angioplasty followed by delayed (> or = 1 month later) repeated angioplasty and stent placement reduces the morbidity associated with endovascular treatment of symptomatic basilar and/or intracranial vertebral artery (VA) stenoses. METHODS: The authors retrospectively reviewed the medical records in a consecutive series of eight patients who underwent planned stent-assisted angioplasty for medically refractory, symptomatic atherosclerotic disease of the intracranial posterior circulation between February 1999 and January 2002. Staged stent-assisted angioplasty was planned for these patients because the extent and degree of stenosis of the VA and/or basilar artery (BA) lesion portended an excessive procedure-related risk. The degree of stenosis, recent onset of symptoms (unstable plaque), vessel tortuosity, and lesion length and morphological feaures were contributing factors in determining procedure-related risk. Patient records were analyzed for location and degree of stenosis, preprocedural regimen of antiplatelet and/or anticoagulation agents, devices used, procedure-related complications, and clinical and radiographic outcomes. Among the patients in whom staged stent-assisted angioplasty was planned, vessel dissection, which necessitated immediate stent placement, occurred during passage of the balloon in one of them. In a second patient, the stent could not be maneuvered through the tortuous VA. In a third patient, the VA and BAs remained widely patent after angioplasty alone, and therefore stent placement was not required. Significant complications among the eight patients included transient aphasia and hemiparesis in one and a groin hematoma that necessitated surgical intervention in another; there was no permanent neurological morbidity. The mean stenosis before treatment was 78%, which fell to 54% after angioplasty, and the mean residual stenosis after stent placement was 30%. At the last follow-up examination, none of the treated patients had further symptoms attributable to the treated stenosis. CONCLUSIONS: The novel combination of initial angioplasty followed by delayed endoluminal stent placement may reduce the neurological morbidity associated with endovascular treatment of long, high-grade stenotic lesions. Attempting to cross high-grade stenoses with higher-profile devices such as stents may result in an embolic shower. Furthermore, neointimal proliferation and scar formation after angioplasty result in a thickened fibrous layer, which may be protective during delayed stent deployment. Larger-scale studies involving multiple centers are needed to elucidate further the lesion morphological characteristics and patient population most likely to benefit from staged procedures.

Aged↗

PubMed2002

Transradial cerebral angiography: an alternative route.

INTRODUCTION: The transradial approach has been well described for arteriography of the coronary vessels. To assess the safety and success rate of the transradial approach for three-vessel or four-vessel diagnostic cerebral arteriography, we reviewed the experience at our institution and compared our complication rates with those found in the literature for transfemoral cerebral angiography and transradial coronary angiography. METHODS: We reviewed the electronic medical records of 129 consecutive patients in whom 132 cerebral angiographic studies were performed by use of a transradial approach between December 1999 and June 2001. A total of 54 selective catheterizations were performed, of which 39 were of the vertebral artery, 11 of the internal carotid artery, and 4 of the external carotid artery. Records were reviewed for periprocedural and delayed complications, indications for diagnostic angiography, and requirement of conversion to a femoral approach. Records were reviewed prospectively for the first 55 procedures and retrospectively for the next 77 procedures. RESULTS: The mean time to initial clinical follow-up was 1.5 months (median, 0.5 mo). The combined rate of periprocedural and delayed complications was 9%, and there were no major complications. Minor periprocedural complications included transient radial artery spasm (four patients), failure to access the brachial artery (two patients), severe pain (one patient), skin desquamation (one patient), and hematoma (one patient). There were no major complications. At the time of follow-up evaluation, these patients were without deficits related to cannulation of the radial artery. CONCLUSION: The transradial approach for cerebral angiography is a safe alternative to the transfemoral route. After transradial cerebral angiography, patients require a shorter observation period and are not restricted to bed rest. As technological developments generate smaller, more pliable endovascular surgical devices, future endovascular surgery may be performed transradially.

Adolescent↗

PubMed2002

Endovascular surgery: the future without limits.

The new millennium brings with it tremendous advances in technology and information sharing. Various medical, surgical, and engineering specialities are becoming more focused, thus enabling experts in these fields to gain insight and understanding previously unappreciated by those who came before us. Economic and technologic evolution will eliminate some of the drawbacks of endovascular therapy, such as persistent neck remnants. It is likely that drug delivery systems exist that would allow maximal benefit with little or no systemic adverse effects. It is likely that devices are available that could minimize various procedural complications. We as future neurosurgeons must persist in the quest to find collaborations that will promote cross-fertilization and cross-pollination among cardiologists, neurosurgeons, physicists, radiologists, neurologists, engineers, and other scientists so that the technology can be translated to reality. It is clear that, in time, transcatheter techniques will replace many operations for the treatment of cerebrovascular pathologies. Let us not allow ourselves the luxury of time.

Angioplasty↗