concurrently deployed by withdrawal of the microcatheter , straddling the thrombus . After placing the device within the thrombus for 3 – 5 minutes , the device is then pulled back in its expanded state along with continuous aspiration from a 50ml syringe via the guide catheter . Up to five passes using this technique may be performed if initially unsuccessful . 11 An improved final recanalisation success rate using Thrombolysis in Cerebral infarction ( TICI ) score of 2b – 3 is often achieved using this combined stentriever – aspiration mechanical thrombectomy . 12
Use of anaesthesia during the procedure The use of general versus local anaesthesia or conscious sedation currently varies .. General anaesthesia reduces subject distress and movement , and it can make the technical aspects easier ; by contrast , conscious sedation allows continuous neurological monitoring for complications , and it avoids any potential hazard of general anaesthetic agents . Two studies presented at the 3rd European Stroke Organisation Conference ( ESOC ) in 2017 ( GOLIATH and ANSTROKE ) both suggested that general anaesthesia and conscious sedation are equally safe . 7 Thus , either approach currently seems reasonable and the decision can be made on the level of local anaesthetic expertise available and the clinical stability of the patient , which may point to direction of either of these approaches .
Figure 2 Basic stentriever technique . A , B ) AP and lateral views of pre-procedural catheter angiogram showing MCA occlusion in a patient with straight cervical ICA ; C ) Microcatheter advanced across the thrombus ; D ) Stentriever positioned across the thrombus ; E , F ) AP and lateral post-procedure catheter angiogram showing complete revascularisation .
Basic stentriever technique Figure 2 shows the basic method for this technique .
A 6F or 8F guide catheter is introduced to the arch of aorta under fluoroscopic guidance and then placed into the target vessel ICA or VBA . 10 A micro catheter is then negotiated across the thrombus by tracking over a guidewire . The stentriever device is then passed through the microcatheter so that it is positioned across the thrombus . Next , the device is unsheathed and
Procedure limitations and potential complications Despite their superiority in improving clinical outcomes in patients with acute ischaemic strokes , stent retrievers are not without complications . Although the stent retriever devices are generally safe , 13 complications of endovascular procedures can result from direct device-related vascular injury , vascular access and the use of radiological contrast media . The most common complications include the vessel perforation , 14 – 16 which occurred in 1.6 % patients in the 5 % positive endovascular trials ( range 0.9 %– 4.9 %); symptomatic intracranial haemorrhage ( 3.6 %– 9.3 %); subarachnoid haemorrhage ( 0.6 %– 4.9 %); arterial dissection ( 0.6 %– 3.9 %); emboli to new territories ( 1.0 %– 8.6 % in randomised controlled trials ); vasospasm ; and vascular access site complications ( including dissection , pseudoaneurysm , retroperitoneal haematoma and infection ). Another side effect of using stents in the treatment of acute ischaemic stroke is acute in-stent thrombosis in cases where the stent is permanently left in place following successful recanalisation . In that case , a halfsystemic loading dose of a factor IIb / IIIa inhibitor , such as eptifibatide or abciximab , may be delivered intra-arterially via the guide catheter . 17 Techniques requiring a larger 8F system have slightly increased risk of arterial injury especially in elderly patients with atherosclerotic vessels . 18
The overall procedural complication rate from recent randomised controlled trials is in the range of 15 %, but it must be emphasised that many do not adversely affect clinical outcome . Stent retriever detachment 19 – 21 is an uncommon complication ( about 2 %– 3 % with first-generation
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