Endovascular thrombectomy efficacy in large ischemic strokes: correspondence

Dear Editor,

Acute stroke is the second leading cause of death worldwide, and it also imposes a significant financial burden, accounting for 3–4% of total health expenditure in most developed countries1. Stroke manifests itself in two forms: ischemic and hemorrhagic. Ischemic strokes (ISs) account for 62% of all strokes worldwide and are typically caused by a disruption of blood flow to specific brain areas, whereas most hemorrhagic strokes are caused by extravasation of blood into the brain parenchyma or ventricles1. For ISs, there are numerous treatment options available, including thrombolysis, thrombectomy, anticoagulants, and many others. Surgical thrombectomy is a procedure used to eject a blood clot from inside an artery or vein, and it has been shown to be an effective treatment option for many ISs. It had, however, not been used on patients with larger strokes for many years2.

Patients with large ISs have extremely poor clinical manifestations, such as brain edemas and death. Endovascular thrombectomy (ET), a thrombus removal with image guidance, has been shown to be more effective than standard medical therapy (MT) in IS patients2. Patients with large ISs, on the other hand, have been vastly underrepresented in the use of thrombectomy. The effectiveness of thrombectomy for large ISs has not been well established.

A Japanese randomized control trial included 203 patients, 101 of whom were assigned to ET and 102 to MT. Almost 27% of patients were given alteplase. Patients with large cerebral infarctions had better functional outcomes with ET than with standard MT. ET patients, on the other hand, had more intracranial hemorrhages (IHs)3. ET patients had an almost equal incidence of hemicraniectomy, edema, and mortality than MT patients. New trials have sufficed to confirm certain positive outcomes of this Japanese study. Huo and colleagues4 recently conducted a study within 24 h of stroke onset, enrolling 456 patients, 231 of whom were assigned to the ET group and 225 to the MT group. The trial was halted earlier than planned, however, a planned interim analysis revealed that 47% of patients in the ET group and 33% of patients in the MT group had good outcomes. ET outperformed MT in terms of overall outcomes at 90 days, but patients receiving ET had more IHs4.

There have also been randomized control trials in which 352 patients from the United States, Europe, Canada, Australia, and New Zealand received ET and standard MT within 24 h of the onset of stroke. The primary outcomes of these trials favored ET, with the majority of thrombectomy patients having improved functional independence and independent ambulation. The incidence and mortality rates of symptomatic IH were nearly equal in both groups, but neurological complications with worse outcomes were more common in the thrombectomy group5. Finally, a recent study by Sarraj et al 2. found that ET combined with medical care provided better clinical results in large IS patients who arrived within 24 h of onset. Although the occurrence of symptomatic IH was low in both trial groups, ∼20% of the ET group patients experienced complications as a result of the procedure2. Furthermore, the ET group had a higher rate of early neurological deterioration due to brain edema associated with reperfusion occurrence than the medical care group. However, the clinical trial was terminated prematurely, which could have resulted in an overestimation of the treatment impact. Prior to randomization, ∼20% of the patients received intravenous thrombolytic therapy due to the inclusion of patients who presented after 4 h of onset and also due to the doctors’ concerns regarding the use of thrombolytic drugs in patients with severe ischemic changes2.

Despite differences in geography, trial procedures, and patient types, the results of all four clinical trials discussed in this paper were strikingly similar. These studies have shown that ET is more effective than standard MT. Neurological complications and IHs, on the other hand, were more common in ET patients. The mortality rates for the two groups were almost the same in all four trials. Despite the high risks of complications such as neurologic worsening, edema, hemicraniectomy, and symptomatic hemorrhage, more large ischemic patients should be recommended for ETs, which may result in higher rates of positive outcomes. Most importantly, more clinical trials will also be required to confirm the validity of these trials discussed in this paper.

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Author contribution

All authors were involved in writing the initial draft. W.A.A.: conceptualized the ideas; W.A.A., O.T.A., F.T.A., A.M., and T.A.-R.: reviewed and edited the manuscript.

Conflicts of interest disclosure

None.

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1. Name of the registry: not applicable.

2. Unique identifying number or registration ID: not applicable.

3. Hyperlink to your specific registration (must be publicly accessible and will be checked): not applicable.

Guarantor

Favour Tope Adebusoye.

Data availability statement

No data available.