• Neurology Clinical Trials
• Neuroimaging
• Ischemia

• Neurology Clinical Trials
• Neuroimaging
• Ischemia
• Neurology

Patients who undergo neuroimaging to identify a favorable penumbral pattern do not benefit from endovascular treatment any differently than people with a nonpenumbral pattern when treated within 8 hours of an acute ischemic stroke, according to Chelsea S. Kidwell, MD, Georgetown University, Washington, DC, USA, who reported results of the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy trial [MR RESCUE; Kidwell CS et al. N Engl J Med 2013]. The results also showed that, regardless of penumbral pattern, clinical and imaging outcomes were no different between patients undergoing embolectomy versus those who received standard medical care for acute ischemic stroke.

MR RESCUE was a Phase 2b, multicenter, randomized, controlled trial that was undertaken to test the hypothesis that the presence of substantial penumbral tissue identifies patients most likely to respond to mechanical embolectomy for acute ischemic stroke. A secondary hypothesis tested was that embolectomy would result in improved functional outcomes compared with standard medical care.

In the study, 118 patients were randomly assigned to embolectomy (n=64) or standard care (n=54) within 8 hours of the onset of symptoms of a large-vessel, anterior-circulation ischemic stroke. All patients were aged 18 to 85 years, had a National Institute of Health Stroke Scale (NIHSS) score >6, and had a premorbid modified Rankin Scale (mRS) score of 0 to 2. Patients were excluded from the study if they were pregnant or had an NIHSS score >30, acute intracranial hemorrhage, rapidly improving symptoms, refractory iodine allergy, proximal carotid stenosis >67% or dissection, international normalized ratio >3.0 or partial thromboplastin time >3 times the normal, or renal failure.

Prior to randomization, all patients underwent pretreatment multimodal MRI or CT neuroimaging and were then stratified according to whether they had a favorable penumbral pattern (ie, substantial salvageable tissue and small infarct core) or a nonpenumbral pattern (ie, large core, or small or absent penumbra). Of the 118 patients, 58% had a favorable penumbral pattern.

In the embolectomy group, 34 had a favorable penumbral pattern and 30 had a nonpenumbral pattern. In the standard-care group, 34 patients had a favorable penumbral pattern and 29 had a nonpenumbral pattern.

The study found no difference in the benefit of endovascular therapy based on penumbral pattern, with a statistically insignificant mean difference of 0.88 between patients with a favorable penumbral pattern versus those with a nonpenumbral pattern based on a 90-day mRS score comparing embolectomy with standard care (p=0.14; Table 1).

There was no difference in clinical or imaging outcomes between patients treated by embolectomy versus standard care regardless of imaging pattern. Among all patients, no difference was found in the 90-day mRS score between embolectomy and standard care (3.9 vs 3.9; p=0.99), and the 90-day mortality (21%) and symptomatic intracranial hemorrhage rate (4%) did not differ between groups.

The study also found no superior benefit with embolectomy over standard care based on imaging pattern. Outcomes of embolectomy and standard care were a mean 90-day mRS score of 3.9 versus 3.4, respectively (p=0.23), for patients with a favorable penumbral pattern and a mean score of 4.0 versus 4.4, respectively (p=0.38), for patients with a nonpenumbral pattern. According to Dr. Kidwell, the study underscores the importance of confirming hypotheses in randomized, controlled trials prior to implementing treatment approaches in clinical practice.

• © 2013 MD Conference Express®