Lahoti S, Gokhale S, Caplan L, Michel P, Samson Y, Rosso C, et al. Thrombolysis in Ischemic Stroke Without Arterial Occlusion at Presentation. Stroke. 2014
It is difficult to justify vessel imaging as a requirement prior to the administration of tPA. Firstly, the majority of strokes do not demonstrate large vessel occlusions because they are due to small-vessels or a large vessels that have recanalized. Secondly, it would create a delay in treatment. The major clinical trials proving the efficacy of IV-tPA did not require such imaging.
It has remained common practice, although not evidence-based, to make a clinical diagnosis of ischemic stroke with a corroborating history, especially in centers without acute MRI capability. Several studies have also demonstrated tPA is safe in the case of stroke mimics, assuming there is no absolute contraindication.
This paper provides evidence that our common practice significantly improves patient outcomes without placing them at high risk. 103 patients who received IV t-PA and 153 who didn’t from several centers were retrospectively compared for 3 month mRS and symptomatic ICH (sICH). Patients also had to have follow-up MRI within 48 hours to exclude stroke mimics from the analysis (a great strength of this study) and follow up CTA or MRA to exclude large vessel occlusion.
Thrombolyzed patients did better than non-thrombolyzed patients when measured by 3 month mRS of 0 (perfect), 0-1 (excellent), or 1-2 (good). Even patients with a resultant mRS of 0 had an adjusted OR of 5.81 (p<0.01). Symptomatic ICH was more common in the thrombolysis group 4.9% vs 0.7% (p=0.04). Number needed to treat for an mRS 0-1 was 5.7 at the cost of 1 in 24 sICH without an increase in poor outcome (mRS 4-6). The adjusted OR for poor outcome, 0.65, was not significant (95% CI 0.31-1.40, p=0.27).
In subgroup analysis, patients were divided into lacunar and non-lacunar strokes. Both groups who received tPA reached statistical significance for mRS 0, but only the non-lacunar group had significantly better outcomes at mRS 0-1 or 1-2. Neither group had significantly worse poor outcomes. Patients who got tPA in both groups had more sICH, 6.1% (5 patients) in the nonlacunar and 3.7% (2 patients) in the lacunar.
“Perfect outcome”, as the authors call it, with an mRS of 0 is an interesting term that I hope becomes common terminology in future articles as the treatment options for acute ischemic stroke continue to improve.
The 2 groups were poorly matched due to small cohort size, namely number of patients, DM, HTN, age, NIHSS. Despite the tPA group being older, having more vascular risk factors, and a higher NIHSS on presentation they still had better outcomes than the no tPA group
Limitations of this study:
– not randomized, so patients who didn’t receive tPA aren’t necessarily comparable to those who did. This introduces treatment bias and the possibility of undocumented exclusion criteria
– retrospective data
How this paper changes my practice:
– citing evidence that giving tPA for patients even in the absence of a vessel occlusion is more likely to help outcome with minimal risk