Mechanical thrombectomy through a ‘carotid–carotid bypass’

An elderly patient presented with acute-onset right-sided weakness and aphasia. A large penumbra was noted in the left middle cerebral artery (MCA) territory without any infarct core. The patient was noted to have a carotid–carotid bypass. This posed certain technical challenge in accessing the intracranial circulation across the carotid bypass; however, the guiding catheter with soft distal segment was successfully navigated coaxially over the aspiration catheter across the bypass and intracranial circulation was accessed for mechanical thrombectomy. Complete recanalisation and reperfusion were achieved with significant neurological recovery of the patient post-thrombectomy. The aim of this report is to emphasise on this rarely encountered situation in thrombectomy and its successful management. The procedure should not be delayed or deferred due to lack of operator experience.

Direct ultrasound-guided puncture of vertebral artery V2 segment during mechanical thrombectomy

An 83-year-old man experienced left upper limb uncontrolled movements preceded by intense gasping during night rest, which progressed to unconsciousness and respiratory arrest requiring intubation. He was diagnosed with acute stroke due to distal occlusion of the basilar artery and received indication for endovascular thrombectomy. Standard endovascular approach includes percutaneous puncture of the femoral or radial arteries; however, the presence of unfavourable vascular anatomies (stenotic origin and tortuosity) did not allow catheterisation of the intracranial vessels through conventional access, and based on the consistent time lapse from onset of symptoms and deterioration of the clinical condition, a direct right vertebral artery ultrasound-guided puncture was performed. After one attempt of a triaxial technique, a complete recanalisation of the basilar artery and of its distal branches was achieved. Direct percutaneous puncture of the vertebral artery represents a rescue access strategy for treatment of posterior circulation stroke when other routes are not feasible.

Reocclusion of the treated vessel due to endothelial injury after mechanical thrombectomy in a patient with acute ischaemic stroke

A 92-year-old woman developed sudden consciousness disturbance, global aphasia and right hemiparesis. She had atrial fibrillation and cardioembolic stroke was diagnosed. Tissue plasminogen activator was administered, and endovascular treatment was initiated. The left middle cerebral artery was occluded and complete recanalisation was achieved after direct aspiration first-pass technique. However, MRI immediately after treatment showed reocclusion. Endovascular treatment was repeated and complete recanalisation was achieved. There was no evidence of cerebral artery dissection, but angiography soon after the second procedure revealed early reocclusion. Ozagrel, an antiplatelet agent, was administered intravenously and prevented reocclusion. Endothelial injury was speculated to have occurred during the first mechanical thrombectomy, leading to recurrent occlusion. Though the patient continued to have right hemiparesis, she recovered from her consciousness disturbance and aphasia after re-treatment.

Accidental guide catheter fracture in mechanical thrombectomy

Endovascular thrombectomy is now the standard of care for large vessel occlusion stroke. The aim is to achieve rapid and complete recanalisation while avoiding complications. Apart from the conventional complications of neurointerventional procedures, mechanical thrombectomy has its unique set of complications, inherent to the disease pathophysiology. We describe an unusual complication of catheter fracture and subsequent distal embolisation into the cerebral vasculature, which was noticed 24 hours after the procedure. Due to a lack of clinical consequences, we decided to manage it conservatively. The patient died within the following few days from respiratory complications unrelated to the stroke or the endovascular thrombectomy procedure. Consequently, we were able to retrieve the fractured segment and carry out histopathological analysis, which helped us to identify exactly its origin from the guide catheter. We believe that systematic reporting and database compilation of such device-related complications will aid in the design and development of neurointerventional devices in the future.

Advances in Medical Revascularisation Treatments in Acute Ischemic Stroke

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment and there has been ongoing research to find a drug that can promote vessel recanalisation more completely and with less side effects. In this review article, the major studies which have validated the use and safety of tPA are discussed. The safety and efficacy of other thrombolytic and anticoagulative agents such as tenecteplase, desmoteplase, ancrod, tirofiban, abciximab, eptifibatide, and argatroban are also reviewed. Tenecteplase and desmoteplase are both plasminogen activators with higher fibrin affinity and longer half-life compared to alteplase. They have shown greater reperfusion rates and improved functional outcomes in preliminary studies. Argatroban is a direct thrombin inhibitor used as an adjunct to intravenous tPA and showed higher rates of complete recanalisation in the ARTTS study with further studies which are now ongoing. Adjuvant thrombolysis techniques using transcranial ultrasound are also being investigated and have shown higher rates of complete recanalisation, for example, in the CLOTBUST study. Overall, development in medical therapies for stroke is important due to the ease of administration compared to endovascular treatments, and the new treatments such as tenecteplase, desmoteplase, and adjuvant sonothrombolysis are showing promising results and await further large-scale clinical trials.

Prediction of thrombus resolution after intravenous thrombolysis assessed by CT-based thrombus imaging

SummaryThe degree of thrombus resolution directly indicates the effectiveness of a thrombolytic drug. We investigated the degree of thrombus resolution and factors associated with thrombus resolution after intravenous (IV) recombinant tissue plasminogen activator (rt-PA) using thin-section noncontrast computed tomography (NCT). Thin-section NCTs were performed before and immediately after IV rt-PA infusion in acute stroke patients. The thrombus volume and Hounsfield unit were measured using three-dimensional imaging software. Immediate recanalisation was assessed immediately after IV rt-PA infusion using CT angiography. During a three-year study period, 130 patients were prospectively enrolled. On baseline thin-section NCT, no thrombi were found in 30 patients (23%). Among the 100 patients with confirmed thrombus, the median volume decreased by 20% on the follow-up NCT. The thrombus was completely resolved in 8%. Of note, an increase in thrombus volume was observed in 20 patients. Independent predictors of thrombus resolution were total rt-PA dose, thrombus location in the M2 segment of the middle cerebral artery, and time from baseline to follow-up NCT. Thrombus resolution increased by 9% per each 10-mg increase in rt-PA (p = 0.045). Immediate complete recanalisation was achieved in 12% of patients. Total dose of rt-PA was independently associated with complete recanalisation [odds ratio [OR] 4.52, 95% confidence interval [CI] 1.345–15.184) and good functional outcome at three months (modified Rankin scale score <3, OR 2.34, 95% CI 1.104–4.962). In conclusion, rt-PA dose was associated with the degree of thrombus resolution, immediate complete recanalisation, and good outcome at three months. CT-based thrombus imaging may be helpful in determining thrombolysis effectiveness.

Lower concentrations of thrombin-antithrombin complex (TAT) correlate to higher recanalisation rates among ischaemic stroke patients treated with t-PA

SummaryAn elevated concentration of the thrombin-antithrombin complex (TAT) has been associated with high mortality rates and poor outcome in ischaemic stroke patients treated with tissue plasminogen activator (t-PA). Moreover, antithrombin drugs have been tested in combination with t-PA in the acute phase of ischaemic stroke to increase treatment efficacy. We aimed to study whether poor outcome associated with TAT among ischaemic stroke patients treated with t-PA could be due to the effects of this complex on recanalisation rates of the middle cerebral artery (MCA) and on haemorrhagic transformation. The TAT levels of 89 patients having a proximal MCA occlusion were measured by ELISA, and the patients were then treated with t-PA. Complete recanalisation was diagnosed by transcranial Doppler (TCD) at 1, 2 and 6 hours post-t-PA infusion and haemorrhagic transformation was identified by computed tomography (CT). Lower levels of TAT were associated with better recanalisation rates at all time-points (1 hour: OR = 24.8 95% CI 1.4–434.8, p = 0.028;2 hours:OR = 6.3 95% CI 1.5–27, p = 0.014; 6 hours: OR = 6.4 95% CI 1.5–26.5, p = 0.011) after adjustment for stroke risk factors. However, no correlation was found between TAT concentration and haemorrhagic transformation. The elevated mortality rates previously observed in patients with high levels of TAT might have been due to revascularisation resistance. Low levels of TAT are not associated with an increase in haemorrhagic complications after t-PA, indicating that the combination of thrombin blockers and t-PA could be a safe and effective treatment for ischaemic stroke in the future.

FIBRINOLYTIC THERAPY WITH STREPTOKINASE AND UROKINASE IN DEEP VEIN THROMBOSIS

336 patients with acute 1-6 day old, and subacute, 1-3 week old deep vein thrombosis were treated with streptokinase (SK) or urokinase (UK) up to April 1, 1985. 175 patients were included in the SK group, 161 patients in the UK group. A standardized SK-heparin and the standardized UK-heparin dosage scheme with 100.000 IU SK/h or 100.000 IU UK/ h were used. In patients with acute deep vein thrombosis a complete recanalisation could be achieved in 67% and a partial recanalisation in 25% with the standardized SK scheme; a complete recanalisation could be achieved in 46%, and a partial recanalisation in 30% with the standardized UK scheme.Since April 1, 1985 we use the ultra high SK dosage scheme, with an initial dose of 250.000 IU SK/h and a maintenance dose of 1.500.000 IU SK/h over.6 hours. So far 28 patients were treated in this way. The results show, that with an ultra high SK-dosage scheme a complete recanalisation could be achieved in 46% and a partial recanalisation in 25% in 1-6 day old deep vein thromboses. The results of both the SK schemes and the UK scheme are discussed in accordance with the haemostaseologica1 parameters.