The MERCI Retrieval System for the management of acute ischaemic stroke--the NNI Singapore experience

<p><b>INTRODUCTION</b>Systemic and local intra-arterial thrombolysis in patients with large vessel ischaemic stroke is hampered by poor re-canalisation rates and risk of haemorrhage. The Merci Retrieval System is an endovascular device for removal of acute intracranial thrombus. We present our initial experience using this device in conjunction with existing thrombolytic therapy already in place in our institute.</p><p><b>MATERIALS AND METHODS</b>Prospective data in all patients presenting with large vessel ischaemic stroke treated using the Merci Retrieval System from July 2007 to March 2009 were analysed. Selection criteria for patients were similar to the multi- Merci trial of 2008. We compared re-canalisation rate, National Institutes of Health Stroke Score (NIHSS) and modified Rankin score (mRS) outcomes to the published trial results.</p><p><b>RESULTS</b>Seventeen patients were reviewed; none suffered immediate post-procedural complications. Fifteen underwent successful thrombus retrieval but in 2 cases the device failed due to technical considerations. Sites of vascular occlusion included: ICA/ICA-'T' junctions 27%, middle cerebral artery 13% and vertebrobasilar artery 60%. Of the 15 patients treated by MERCI with or without adjuvant thrombolytic therapy, complete re-canalisation was achieved in 60%, partial re-canalisation in 20%, partial re-canalisation with persistent distal vessel occlusion in 6% and failure of re-canalisation in 14%. Asymptomatic haemorrhage occurred in 33% and there was 1 death (6%) from symptomatic haemorrhage. Pre-treatment median NIHSS was 17.88 and 9.5 immediately post-treatment. Median mRS at 30 days was 2.6 for patients who achieved complete re-canalisation and 4.5 in failure or partial re-canalisation with or without persistent distal vessel occlusion.</p><p><b>CONCLUSION</b>Re-canalisation rates using the Merci Retrieval System was comparable to the multi-Merci trial. Haemorrhagic complications and safety were also found to be satisfactory. Importantly, treatment success with eventual good clinical outcome hinges strongly on the ability of the device to achieve complete re-canalisation.</p>

Multi-detector computer tomography angiography in the initial assessment of patients acutely suspected of having intracranial aneurysm rupture

<p><b>INTRODUCTION</b>Multi-detector computer tomography angiography (CTA) provides a fast non-invasive assessment of the cerebral vessels, is readily available in an acute setting and can potentially replace invasive digital subtraction angiography (DSA) for the diagnosis of intracranial vascular lesions in an emergency setting. We report our experience in the use of emergent cerebral CTA versus DSA in the assessment of patients presenting acutely with symptoms suspicious of brain aneurysm rupture.</p><p><b>MATERIALS AND METHODS</b>Thirty-seven consecutive patients presenting acutely with clinical suspicion of brain aneurysm rupture were evaluated over a 4-month period from January to April 2008. CTA with peripheral intravenous contrast injection was performed on a 32 slice helical scanner. DSA was performed within 48 hours for all cases when CTA was the initial assessment. Studies were assessed via radiology reports using DSA or surgery as the gold standard.</p><p><b>RESULTS</b>All except for 3 patients had CTA as the initial study. There were 26 cerebral aneurysms detected by CTA in these 37 patients, with 9 negative studies. There were 2 patients with arteriovenous malformations (AVM), 1 with AV fistula (AVF), 1 tumoral bleed, 2 vertebral dissections, and 1 missed sagittal sinus thrombosis (CVT) on CTA. Based solely on CTA assessment, 3 patients had direct surgical clipping of the aneurysm, while 4 proceeded to direct endovascular coiling.</p><p><b>CONCLUSION</b>Emergent CTA is a non-invasive, reliable and viable alternative to emergent DSA for the assessment of the cerebral vessels in the acute assessment of patients presenting with symptoms suspicious of brain aneurysm rupture. Where positive, it can serve as a guide to therapeutic decisions. Review of CTA source data is essential, especially for small lesions and for post-clipping assessment.</p>