Alejandro Fuerte, MD

Levine SR, Weingast SZ, Weedon J, Stefanov DG, Katz P, Hurley D, et al. To Treat or Not to Treat? Exploring Factors Influencing Intravenous Thrombolysis Treatment Decisions for Minor Stroke. Stroke. 2018

The activase/alteplase package insert from the Food and Drug Administration was updated in February 2015. Despite this, controversy continues over the criteria for the use of this drug in minor stroke, defined as National Institutes of Health Stroke Scale (NIHSS) score 1 to 5. In this article, Levine et al explore clinical factors influencing alteplase treatment decisions for patients with ictus minor.

This is a descriptive study. A committee of stroke experts identified the key factors in making decisions about the use of alteplase. The most prominent factors on the basis of which the study was developed were the following: all patient-dependent: National Institutes of Health Stroke Scale (NIHSS), NIHSS area of primary deficit, baseline functional status, previous ischemic stroke (IS), previous intracerebral hemorrhage (ICH), recent anticoagulation, and temporal pattern of symptoms in first hour of care. A fractional factorial design was used to provide unconfounded estimates of the effect of the 7 main factors, plus first-order interactions for the NIHSS. A joint statistical analysis was then applied.

With these 7 factors, practical questions about minor stroke were developed and sent to neurologists and emergency physicians using networks such as StrokeNet to obtain the details. For each clinical case, participants were asked to provide the probability of administration of alteplase intravenously from rarely (0) to always (5). Most of our surveyed physicians were male, trained in neurology, practicing in an urban setting—over half academically, within a comprehensive stroke center, and with telestroke available.

Treatment mean probabilities for individual vignettes ranged from 6% to 95%. The predictive power of the conjoint model was modest; only ≈25% of variance was explained. The model including all possible interactions was not much better (30%). Four of the 7 factors accounted jointly for 58% of total relative importance within the conjoint model: previous intracerebral hemorrhage (18%), recent anticoagulation (17%), NIHSS (13%), and previous ischemic stroke (10%). This suggests that there are possibly other factors involved in the decision-making process that were not included.

With the data obtained from the surveys, an analysis was made of the medical-dependent factors (age, years of practice, sex and area of training (neurology/emergency medicine)). This model showed that none of these 4 physician characteristics independently significantly (P<0.05) predict probability of treatment.

The authors point out that there were a number of limitations in the study: The total number of physicians who received the survey could not be established, which limited the ability to generalize without bias; most of the specialists who participated worked in comprehensive stroke centers, where they are usually more likely to treat; the severity of previous HCI or SI was not taken into account; the type of anticoagulation was not detailed; only 3 spheres of deficit were studied and the degree of disability was not specified; do not include any early vascular imaging or perfusion data in the vignettes, although these have increasingly been used for acute treatment decision-making; and it was assumed that patients presented within 60 minutes of the onset of symptoms so that this could have skewed responses toward alteplase treatment. Finally, Levine et al refer to the PRISMS study, a randomized placebo-controlled trial of intravenous alteplase in minor stroke that has recently been completed and which aims to clarify the current uncertainty on this question.