No Benefit for IV tPA Before Mechanical Thrombectomy in Ischemic Stroke

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No benefit was found for IV tPA before mechanical thrombectomy in acute ischemic stroke.
No benefit was found for IV tPA before mechanical thrombectomy in acute ischemic stroke.

Administering intravenous thrombolysis (IVT) prior to mechanical thrombectomy (MT) did not improve outcomes compared with MT alone in patients with acute ischemic stroke (AIS) due to a large vessel occlusion, according to a study published in JAMA Neurology.

The majority of patients in trials evaluating MT for AIS were also treated with IVT, but it is unclear whether administering IVT prior to MT provides additional benefit over MT alone.

Potential benefits of IVT include increasing the chance of reperfusion with MT and treating microvascular thrombosis, but these benefits may be negated or outweighed by potential drawbacks such as delaying the start of MT and increasing the risk of hemorrhagic complications.

In a post hoc pooled analysis of the SWIFT (Solitaire With the Intention for Thrombectomy) and STAR (Solitaire Flow Restoration Thrombectomy for Acute Revascularization) trials, the investigators compared IVT (tissue plasminogen activator [tPA]) plus MT vs MT alone in patients with AIS due to a large vessel occlusion.

A total of 346 patients were enrolled in the SWIFT and STAR studies, but 55 were excluded from this analysis since they were treated with the Merci Retriever® clot retrieval device (Concentric Medical,  Inc), which is no longer commonly used for MT. Of the 291 patients remaining, 160 received IVT and MT and 131 received MT alone. Patients who underwent MT were treated with the SolitaireTM flow restoration stent retriever (Covidien/Medtronic).

Compared with the MT-only group, the IVT plus MT group had lower rates of diabetes (13.8% vs 24.4%; P =.02) and atrial fibrillation (33.1% vs 47.3%; P =.02) and lower median Alberta Stroke Program Early CT Score (ASPECTS; 8 vs 9; P =.04).

Similar percentages of patients in both treatment groups had successful reperfusion, emboli to new territory, symptomatic intracranial hemorrhage, functional independence (modified Rankin Scale score of 0 to 2) at 90 days, and mortality at 90 days. Vasospasm was more common among patients treated with IVT plus MT than among patients treated with MT alone (26.9% vs 13.7%; P =.006), but this finding was not significant in the adjusted multivariate analysis.

No significant differences were found between the groups in the time from hospital arrival to groin puncture, number of passes during the MT procedure, or the rates of modified thrombolysis in cerebral infarction (mTICI) 2b or 3 reperfusion.

“The results indicate that treatment of patients experiencing AIS due to a large vessel occlusion with IVT before MT does not appear to provide a clinical benefit over MT alone,” the authors wrote. However, the investigators also noted that this study had several important limitations. Small sample size may have contributed to the lack of differences in outcomes, and not all patients treated with IVT plus MT received the same dose of tPA. In addition, patients were not randomly assigned to receive IVT treatment, and most patients who underwent MT alone did not receive IVT due to contraindications. However, approximately one-third of patients in the MT-only group did not have contraindications to tPA; “[t]his finding reflects the fact that local treatment protocols in some of the participating centers allowed direct treatment with MT in patients who were eligible for treatment with IVT,” the authors wrote.

The researchers state that their findings should be interpreted with caution, and that more information is needed. “On the basis of these data, we believe that a randomized clinical trial directly comparing both strategies is warranted,” they concluded.

Reference

Coutinho JM, Liebeskind DS, Slater L-A, et al. Combined intravenous thrombolysis and thrombectomy vs thrombectomy alone for acute ischemic stroke: a pooled analysis of the SWIFT and STAR studies [published online January 9, 2017]. JAMA Neurol. doi:10.1001/jamaneurol.2016.5374

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