Study Design
The Warfarin–Aspirin Recurrent Stroke Study (WARSS) was an
investigator-initiated, randomized, double-blind, multicenter clinical
trial conducted in 48 academic medical centers in the United
States and sponsored by the National Institute of Neurological
Disorders and Stroke. It also served as the basis for four parallel
stroke studies.
The trial was formulated and designed by the stroke
research staff at the Neurological Institute of Columbia Presbyterian
Medical Center. Clinical data were collected and monitored
by the data-management center in the Stroke Unit at the Neurological
Institute. Management of data on anticoagulant therapy,
double-blinding procedures, and statistical analysis were conducted
by the statistical-analysis center of the Department of Biostatistics,
Mailman School of Public Health, Columbia University. Study medications
were bottled, packaged, and distributed by Quintiles
(Mount Laurel, N.J.). To eliminate variations between laboratories,
blood samples for determination of the INR were processed
centrally by Quest Diagnostics (Teterboro, N.J.). The study
protocol was approved by the institutional review board at each
participating center. Written informed consent was obtained from