Similar Benefits for Thrombectomy, Medical Management, in Mild Stroke

Mechanical thrombectomy (MT) and best medical management (bMM) have comparable outcomes in patients who have had a mild stroke, new research suggests.

Investigators conducted a study and performed a meta-analysis of other studies, comparing MT and bMM in patients with mild-deficits emergency larger-vessel occlusion (mELVO).

They found no difference between the two therapeutic approaches in 3-month functional outcomes, 3-month mortality, and rate of symptomatic intracranial hemorrhage (sICH), although MT was associated with higher odds of asymptomatic intracranial hemorrhage (aICH), compared with bMM.

The meta-analysis that pooled the findings of the current study with previous studies on acute stroke patients with mELVO yielded similar results, but no association between MT and aICH.

"We need a randomized controlled trial to resolve this clinical equipoise," lead author Nitin Goyal, MD, assistant professor of neurology, University of Tennessee Health Science Center, Memphis, told Medscape Medical News.

"In the meantime, the practicing clinicians should continue to offer endovascular treatment or best medical management to this subgroup of stroke patients, according to their institutional protocol," he said.

The study was published online September 23 in JAMA Neurology.

Conflicting Results

All recent randomized trials comparing endovascular treatment and medical management in large vessel occlusion stroke excluded patients with mild deficit, except for 10 patients in the MR-CLEAN and four patients in the EXTEND-1A trials, Goyal said.

"Up to 10% of patients with large vessel occlusions can have mild deficits in presentation, and we don't know whether or not to treat this subgroup with endovascular intervention because of lack of data," he continued, noting that previous single- or multicenter studies have "provided conflicting results."

For this reason, Goyal and colleagues decided to conduct a multicenter study and meta-analysis "on this important topic."

The study was a retrospective analysis of consecutive patients with acute ischemic stroke (AIS) with mELVO (defined as National Institutes of Health Stroke Scale [NIHSS] scores of < 6 points) presenting to 16 endovascular stroke centers in North America, Europe, and Asia during a 5-year period (2013-2017).

The researchers pooled the data to investigate the safety and efficacy outcomes in patients with mELVO (n = 251) who were treated either with bMM, which included treatment with intravenous thrombolysis (IVT) or with MT, with or without IVT (n = 138; 65 women; mean age, 65.2 years; median NIHSS score, 4; interquartile range [IQR], 3-5 and n = 113; 51 women; mean age, 64.8 years; median NIHSS score, 3; IQR, 2-4, respectively).

Efficacy outcomes of interest included 3-month functional independence (FI), 3-month favorable functional outcome (FFO), distribution of Modified Rankin Scores (mRS) at discharge and 90 days, neurological improvement during hospitalization, successful reperfusion, length of intensive care unit stay, and length of hospital stay.

Safety outcomes included 3-month all-cause mortality, sICH, and aICH.

Increased Risk of aICH

In patients treated with MT, proximal occlusions, and IV thrombolysis tended to be more common and median admission NIHSS scores were higher in the MT group (4 vs 3 points; P < .001).

Current smoking was more common in patients receiving bMM.

Unadjusted analyses showed that patients treated with bMM had lower rates of aICH (4.6% vs 17.5%; P = .002), compared with those treated with MT.

They also had lower median mRS scores at hospital discharge and shorter median length of hospital stay, compared with their MT counterparts, but the two groups did not differ in terms of sICH, neurological improvement during hospitalization, 3-month FFO, 3-month FI, 3-month mortality, and distribution of 3-month mRS scores.

After imputation of missing follow-up evaluations, the rate of 3-month FI was found to be lower in MT (77.4% vs 88.5%; P = .02).

In multivariable analyses adjusting for potential confounders (eg, age, admission NIHSS score, pretreatment with IVT, admission glucose, and admission systolic blood pressure), MT was found to be associated with higher odds of aICH (odds ratio [OR], 11.07; 95% confidence interval [CI], 1.31 - 93.53; P = .03).

On the other hand, no associations were found between treatment modality and the likelihood of sICH, FFO, FI, functional improvement, or mortality at 3 months.

"In terms of safety, our multicenter study documents an increased risk of asymptomatic ICH with MT, even after adjustment of potential confounders," the authors summarize.

"In terms of efficacy, MT was associated with lower odds of 3-month FI in multivariable models adjusting for confounders, after imputation of missing follow-up data, but this association was not detected in the analysis that excluded patients with missing 3-month follow-up evaluations," they write.

Disabling vs Non-Disabling Effects

The meta-analysis focused on four studies, including the current study, that met the inclusion criteria (n = 843 patients).

Trials were required to include patients with AIS with ELVO and mild neurological severity for MT or medical treatment with or without IVT.

In unadjusted analyses, there was no association between treatment modality and asymptomatic ICH (4 studies; OR, 1.85; 95% CI, 0.34 - 10.13; P = .48), 3-month FFO (4 studies; OR, 0.96; 95% CI, 0.71 - 1.30; P = .78), 3-month FI (4 studies; OR, 0.94; 95% CI, 0.48 - 1.86; P = .86), and 3-month mortality (OR, 1.71; 95% CI, 0.52 - 5.61; P = .38).

There was no heterogeneity noted for 3-month FFO, researchers report, but substantial heterogeneity was observed for aICH, 3-month FI, and 3-month mortality.

Mechanical thrombectomy was associated with higher odds of sICH (4 studies; OR, 5.52; 95% CI, 1.91 - 15.49; P = .002) in unadjusted analyses without an evidence of heterogeneity, the authors report. The association between MT and sICH did not persist in adjusted analyses that excluded two studies (OR, 2.06; 95% CI, 0.49 - 8.63; P = .32; I² = 0%).

"We detected no association between treatment modality and 3-month FFO (3 studies; OR, 1.16; 95% CI, 0.75 - 1.79); 3-month FI (3 studies; OR, 1.24; 95% CI, 0.61 - 2.53); 3-month mortality (2 studies; OR, 1.34; 95% CI, 0.56 - 3.22); and sICH (2 studies; OR, 2.06; 95% CI, 0.49 - 8.63) in adjusted analyses," they write.

"Our study did not have information on the type of initial deficits, so I do feel that it is reasonable to offer endovascular intervention to the patients with low NIHSS and large vessel occlusions if they have disabling deficits, such as aphasia or hemianopia, in comparison to patients with nondisabling deficits, such as dysarthria or facial droop," Goyal commented.

"However, we do not have any data proving this hypothesis," he added.

No Rush to Surgery

Commenting on the study for Medscape Medical News, Gaurav Gupta, MD, associate professor of neurology, and director, Cerebrovascular and Endovascular Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, said that the "approach and design are well thought of and the statistics are well done."

Gupta, who was not involved with the research, said that the "take-home message from this study is that in patients with mild deficits, emergent large vessel occlusion, or acute stroke with NIHSS < 6, both surgical intervention with mechanical thrombectomy and nonsurgical best medical management have similar outcomes."

He noted that in patients who underwent MT, there was a higher risk of post-procedural ICH, "therefore not all patients with mild deficit strokes should be rushed to surgical intervention and can be treated with medical management as well."

He cautioned that, since there are "several limitations to this study, no conclusions could be made regarding the treatment effect and for that conclusion to be made, a larger randomized controlled trial will need to be done."

The authors agree. "Future randomized clinical trials are required to definitely evaluate the potential efficacy of MT compared with bMM in patients with ELVO presenting with mild neurological deficits," they write.

No source of funding listed. Goyal and Gupta have disclosed no relevant financial relationships. The other study authors' disclosures are listed on the original paper.

JAMA Neurol. Published online September 23, 2019. Abstract

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