Neurology: Stroke symptoms as a surrogate measure of primary stroke prevention trials: CREST experience

Using alternative endpoints can reduce sample size
while maintaining statistical power.
A study published in Neurology identified stroke event symptoms as a surrogate endpoint for revascularization
in asymptomatic patients in a multicenter randomized carotid artery post-hoc comparison of endartectomy versus stent placement trials (cREST).

CREST assesses stroke symptoms
using the Stroke-Free Status Questionnaire (QVSS) at baseline and follow-up.
While the primary analysis at CREST defined "asymptomatic" as 180 days without stroke/transient ischemic attack (TIA), the population here is further limited
by the need for stroke symptoms at baseline.
The definition of stroke for event determination is the same as for the initial analysis; Incident stroke symptoms are defined as ≥ stroke symptoms
occurring at follow-up.
Three endpoints to assess differences in treatment for stenting (CAS) and endarterectomy (CEA): Diagnosed stroke, stroke symptoms, and Diagnosed stroke or stroke symptoms
.

The low incidence of stroke events in asymptomatic patients challenges the assessment of differences in treatment between CAS and CEA
.
Using event stroke symptoms as a surrogate result increased the number of events more than
fourfold.
Analysis showed that previously unreported cerebrovascular risk factors differed significantly from
those for cerebrovascular disease.
It is suggested that broadening the endpoints of primary stroke prevention trials to include surrogate events such as stroke event symptoms could make the trial more feasible
.

Source: Meschia JF, Brott TG, Voeks J, Howard VJ, Howard G.
Stroke Symptoms As a Surrogate in Stroke Primary Prevention Trials: The CREST Experience [published online ahead of print, 2022 Aug 26].
Neurology.
2022; 10.
1212/WNL.
0000000000201188.
doi:10.
1212/WNL.
0000000000201188