Intra-arterial thrombolysis of embolic middle cerebral artery using collateral pathways

Background and purpose: Cervical internal carotid artery (ICA) occlusion associated with middle cerebral artery (MCA) embolic occlusion requires prompt revascularization to prevent devastating stroke. With the advent of endovascular techniques for chemical and mechanical thrombolysis, the clinical outcome of patients with major arterial occlusions will improve. Finding the most expedient pathway to the site of end organ occlusion for thrombolysis is important. Methods: We present two cases of acute stroke secondary to thrombotic occlusion of the cervical ICA associated with MCA embolic occlusion treated with intra-arterial thrombolysis via catheter navigation through the posterior communicating artery to the site of MCA arterial occlusion. No attempt was made to transverse the occluded ICA. Results: Near complete restoration of flow was achieved in one patient and minimal vessel reopening was observed in the other patient. Both patients had good outcomes. Conclusion: Intra-arterial thrombolysis via Circle of Willis collaterals such as the posterior communicating artery for the treatment of acute thrombotic occlusion of the cervical internal carotid artery associated with embolic occlusion of the middle cerebral artery is a therapeutic option. This treatment option avoids the potential complications of navigating through an occluded proximal internal carotid artery and may expedite reopening of the MCA

Circle of Willis Collateral During Temporary Internal Carotid Artery Occlusion I: Observations From Digital Subtraction Angiography

INTRODUCTION: Impaired collateral circulation can lead to stroke during carotid endarterectomy. Carotid stump pressure (CSP) is used as a surrogate measure of collateral flow. The objective was to determine whether anatomical features obtained from digital subtraction angiography correlate with CSP during temporary internal carotid artery occlusion. The second objective was to use these features in combination to predict CSP. METHODS: Digital subtraction angiographies from 102 patients obtained before endarterectomy were reviewed for anatomical variables including: degree of ipsilateral and contralateral carotid artery stenosis; patency of the anterior communicating artery; presence of cross-flow into ipsilateral middle cerebral artery branches; and size (\u3c or ≥1 mm calibre) of the ipsilateral proximal anterior cerebral (A1), the contralateral A1, and the ipsilateral posterior communicating arteries. At surgery, systemic mean arterial pressure (MAP) and CSP were recorded. Multiple regression analysis was used to assess for anatomical features significantly associated with CSP. A predicted CSP equation was applied to 54 subsequent patients and correlated with measured CSP. RESULTS: Variables correlating with CSP included MAP (p=0.001); the presence of severe contralateral carotid stenosis (p=0.002); patency of the anterior communicating artery (p=0.013); and the size of the contralateral A1 segment (p=0.029). Angiographic cross-flow, ipsilateral A1 size, and ipsilateral posterior communicating artery size were not significant. Predicted CSP correlated significantly with measured CSP (p\u3c0.0001; R 2=0.34). CONCLUSIONS: Anatomical features and systemic MAP are associated with carotid stump pressure during internal carotid artery occlusion and account for a significant amount of its variation

Enterprise-level groupware choices: Evaluating Lotus Notes and Intranet-based solutions

Abstract. This paper considers collaborative software at the enterprise level, specifically Lotus Notes and alternatives which use Intranet-based (World Wide Web) technologies. We examine the strategic reasons, both short-term and long-term, motivating firms ’ choices in the decision phase and organizational issues in the implementation phase in three exploratory case studies. We review prior coordination technology literature to show that our focus on the decision faced by senior management of which groupware system to implement is a useful and novel perspective to pursue. We argue that this choice, and its consequences, is of crucial importance to the firm. To understand more fully the nature of the decision, we consider a thematic pair of related issues: Internet standards and interoperability. Why are so-called ‘Open Systems ’ a major factor to some firms and not important to others? Why is the proprietary nature of Lotus Notes a stumbling block to some firms and a strategic advantage to others? We explore enterprise-level groupware expectations and requirements in our case studies to address these interesting questions. The final section focuses on predicting change to understand when an organization might reverse its initial enterprise-wide collaborative strategy