Figure 3.

Ongoing fall in ipsilateral stroke rate in patients with ≥50% asymptomatic carotid stenosis given medical intervention alone between 1984 and 2013 (2, 21). Sixty seven percentage relative (or 1.7% absolute) fall in the reported average annual ipsilateral stroke rate in patients with ≥50% ACS given medical intervention alone from 1984 to 2013. Fifty six percentage relative fall since ACAS was published in 1995 with 834 medically treated patients, ACAS result highlighted by a black box (35). Black diamonds are study results with corresponding sample sizes. As in 2009, the Ryan-Holm stepdown Bonferroni correction was made for multiple comparisons (converting raw P-values to P'-values, SYSTAT 13, SYSTAT Software Inc) (21). UPL and LPL, respectively, = upper and lower 95% prediction limits for new population rate estimates; UCL and LCL (dashed lines), respectively = upper and lower 95% confidence limits for the population regression line; WRL, weighted regression line; ACAS, Asymptomatic Carotid Atherosclerosis Study (35); CREST-1, Carotid Revascularization Endarterectomy vs. Stenting Trial (65). **Indicates two studies including a small minority with remote ipsilateral stroke/TIA at baseline (94, 95). These were included in this analysis because the regression line was not appreciably different with (y = 2.861–0.061x, P' for slope and y intercept < 0.00000 and r² = 0.379) (2) or without them (y = 2.720–0.051x, P' for slope and y intercept < 0.00000 and r² = 0.275) (12).