To the Editor.
—I was disappointed with the presentation of the "Controversy" on shunting during carotid endarterectomy. In Ferguson's article,1 inconsistent numbers distracted from his message; confirmed from his own citation,2 there appear to have been 131 procedures with stump pressure monitoring (not 113 or 121 as stated in the article), ten of which (not nine) had clamped values less than or equal to 25 mm Hg. But more lamentable was Hachinski's missed opportunity to indicate the crucial differences between the positions taken,3 leaving the erroneous implication that this is merely a technical neurosurgical question, about which there is really little practical dispute. On the contrary, this issue is important to any neurologist interested in the critical assessment of stroke risk.Ferguson's contribution has been to challenge the conventional wisdom of intraoperative monitoring methods and their criteria for shunting, and to show that patients suffer relatively infrequently