Impact of age and baseline NIHSS scores on clinical outcomes in the mechanical thrombectomy using solitaire FR in acute ischemic stroke study

Mechanical Thrombectomy Is Now the Gold Standard for Acute Ischemic Stroke: Implications for Routine Clinical Practice

BACKGROUND

This review aims to summarize the findings of the recently published randomized controlled studies which provide overwhelming evidence in support of mechanical thrombectomy for acute ischemic stroke with large artery occlusion. The five studies, Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN), Endovascular Revascularization with Solitaire Device versus Best Medical Therapy in Anterior Circulation Stroke within 8 h (REVASCAT), Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke (ESCAPE), Solitaire™ FR as Primary Treatment for Acute Ischemic Stroke (SWIFT PRIME) and Extending the Time for Thrombolysis in Emergency Neurological Deficits with Intra-Arterial Therapy (EXTEND IA) have demonstrated the critical role of selecting patients by advanced neuroimaging, the superior recanalization capacity of stent retrievers and the effects of minimization of work processes delay.

SUMMARY

This review outlines lessons gained from the 5 positive studies which assessed mechanical thrombectomy as part of endovascular therapy for patients with proximal artery occlusion in the internal carotid and middle cerebral arteries. It discusses the role of age and stroke severity on treatment while also comparing the unique trial designs and selection criteria used amongst the 5 studies. In addition to examining the importance of unique imaging parameters such as collateral circulation, mismatch ratio and ischemic core volume, the review outlines differences in workflow parameters within the context of outcome. Finally the benefit of neuroimaging to broaden treatment eligibility and the issues associated with general anesthesia will be discussed in this review.

KEY MESSAGES

Questions remain over the applicability of mechanical thrombectomy to stroke subgroups including wake-up strokes and basilar artery thrombosis. The role of imaging is integral to this process and can lead to broadening eligibility criteria in the future. Workflow practices have been streamlined in the 5 positive randomized controlled studies, but guidelines will need to be revised accordingly if similar patient outcomes are to be replicated in a wider population.

Combined neurothrombectomy or thrombolysis with adjunctive delivery of 3K3A-activated protein C in acute ischemic stroke

In the treatment of acute ischemic stroke (AIS), vessel recanalization correlates with improved functional status and reduced mortality. Mechanical neurothrombectomy achieves a higher likelihood of revascularization than intravenous thrombolysis (IVT), but there remains significant discrepancy between rates of recanalization and rates of favorable outcome. The poor neurological recovery among some stroke patients despite successful recanalization confirms the need for adjuvant therapy, such as pharmacological neuroprotection. Prior clinical trials of neuroprotectant drugs failed perhaps due to inability of the agent to reach the ischemic tissue beyond the occluded artery. A protocol that couples mechanical neurothrombectomy with concurrent delivery of a neuroprotectant overcomes this pitfall. Activated protein C (APC) exerts pleiotropic anti-inflammatory, anti-apoptotic, antithrombotic, cytoprotective, and neuroregenerative effects in stroke and appears a compelling candidate for this novel approach.

Predictors of Outcome, Complications, and Recanalization of the Solitaire Device

BACKGROUND:

The use of mechanical thrombectomy in the management of acute ischemic stroke is becoming increasingly popular.

OBJECTIVE:

To identify notable factors that affect outcome, revascularization, and complications in patients with acute ischemic stroke treated with the Solitaire Flow Restoration Revascularization device.

METHODS:

Eighty-nine patients treated with the Solitaire Flow Restoration Revascularization device (ev3/Covidien Vascular Therapies, Irvine, California) were retrospectively analyzed. Three endpoints were considered: revascularization (Thrombolysis In Cerebral Infarction), outcome (modified Rankin Scale score), and complications. Univariate analysis and multivariate logistic regression were conducted to determine significant predictors.

RESULTS:

The mean time from onset of symptoms to the start of intervention was 6.7 hours. The average procedure length was 58 minutes. The mean NIH Stroke Scale (NIHSS) score was 16 on arrival and 8 at discharge. Of the patients, 6.7% had a symptomatic intracerebral hemorrhage, 16.8% had fatal outcomes within 3 months post-intervention, and 81.4% had a successful recanalization. Thrombus location in the M1 segment of the middle cerebral artery was associated with successful recanalization (thrombolysis in cerebral infarction 2b/3) (P = .003). Of the patients, 56.6% had a favorable outcome (modified Rankin Scale score at 3 months: 0–2). In patients younger than 80 years of age, 66.7% had favorable outcome. Increasing age (P = .01) and NIHSS score (P = .002) were significant predictors of a poor outcome. On multivariate analysis, NIHSS score on admission (P = .05) was a predictor of complications. On univariate analysis, increasing NIHSS score from admission to 24 hours after the procedure (P = .05) and then to discharge (P = .04) was a predictor of complications. Thrombus location in the posterior circulation (P = .04) and increasing NIHSS score (P = .04) predicted mortality.

CONCLUSION:

The Solitaire device is safe and effective in achieving successful recanalization after acute ischemic stroke. Important factors to consider include age, NIHSS score, and location.

Evolution of endovascular mechanical thrombectomy for acute ischemic stroke

Acute ischemic stroke (AIS) is a common medical problem associated with significant morbidity and mortality worldwide. A small proportion of AIS patients meet eligibility criteria for intravenous thrombolysis (IVT) with recombinant tissue plasminogen activator, and its efficacy for large vessel occlusion is poor. Therefore, an increasing number of patients with AIS are being treated with endovascular mechanical thrombectomy when IVT is ineffective or contraindicated. Rapid advancement in catheter-based and endovascular device technology has led to significant improvements in rates of cerebral reperfusion with these devices. Stentrievers and modern aspiration catheters have now surpassed earlier generation devices in the degree and rapidity of revascularization. This progress has been achieved with no concurrent increase in risk of major complications or mortality, both when used alone or in combination with IVT. The initial randomized controlled trials comparing endovascular therapy to IVT for AIS failed to show superior outcomes with endovascular treatment, but key limitations of each trial may limit the significance of these results to current practice. While endovascular devices and operator experience continue to evolve, we are optimistic that this will be accompanied by improvements in patient outcomes. This review highlights the major endovascular devices used in current practice and the trials which have investigated their efficacy.