Stroke: IV thrombolysis appears efficacious for lacunar infarcts

Takeaway

• Intravenous (IV) thrombolysis with alteplase (Activase) improves functional outcomes in patients with lacunar stroke.

Why this matters

• Uncertainty regarding benefit of pharmacologic reperfusion in lacunar infarcts, given underlying microvascular occlusion.

Key results

• Treatment similarly beneficial regardless of stroke subtype (lacunar vs nonlacunar; P for interaction=.94).
• Favorable outcome with alteplase vs placebo:
  • Lacunar stroke: 59% vs 46% (aOR, 1.67; 95% CI, 0.77-3.64).
  • Nonlacunar stroke: 51.8% vs 40.6% (aOR, 1.62; 95% CI, 1.04-2.51).
• Lacunar stroke subset also trended toward better modified Rankin Scale scores with alteplase vs placebo (adjusted common OR, 1.94; 95% CI, 0.95-3.93).
• In the lacunar stroke subset, alteplase vs placebo was associated with slightly more deaths (1 vs 0), symptomatic intracranial hemorrhages (1 vs 0).

Expert comment

• In an editorial, Pooja Khatri, MD, MSc, writes, "Emergency departments that have a policy of using CT imaging first will have to take many patients without occlusions visualized on CT angiography to the MRI scanner expeditiously, to avoid missing patients with lacunar infarcts. An MRI approach, which can consider mismatch strategies of perfusion-weighted imaging vs diffusion-weighted imaging and diffusion-weighted imaging vs fluid-attenuated inversion recovery sequences at the same time, may be the most inclusive and efficient approach for the largest proportion of patients."

Study design

• Exploratory secondary post hoc analysis of European randomized controlled WAKE-UP trial among 503 patients with acute stroke of unknown onset time, lesion visible on diffusion-weighted MRI.
• Randomization: intravenous alteplase vs placebo.
• 108 patients had lacunar infarcts, 395 patients had nonlacunar infarcts.
• Main outcome: favorable outcome (adjusted score of 0 to 1 on modified Rankin Scale at 90 days).
• Funding: European Union Seventh Framework Program.

Limitations

• Trial not powered for stroke subsets.
• Smaller lacunar subset.
• Potential unmeasured, residual confounding.