To the Editor:
I read with interest the recent article by Young et al,1 in which the authors state in the abstract: “Of the 721 patients who underwent CEA [carotid endarterectomy], 1 died and 10 others had strokes within 30 days (1.5%). Of the 415 who underwent arteriography after randomization but before CEA, 5 (1.2%) suffered transient ischemic attack or stroke caused by arteriography. Thus, a nearly equal risk of stroke was associated with both CEA and carotid arteriography.” The authors evidently consider transient ischemic attack (TIA) equivalent to stroke in the analysis of morbidity related to angiography but not for morbidity related to CEA.
In the authors’ Table 2, among 415 patients undergoing postrandomization angiography, stroke or TIA occurred during angiography or the next day in 6 patients (4 strokes, 2 TIAs). Four of these 6 patients proceeded on to surgery. Evidently 2 of 415 (0.5%) had significant events at the time of postrandomization angiography.
- Copyright © 1997 by American Heart Association
Young B, Moore WS, Robertson JT, Toole JF, Ernst CB, Cohen SN, Broderick JP, Dempsey RJ, Hosking JD, for the ACAS Investigators. An analysis of perioperative surgical mortality and morbidity in the Asymptomatic Carotid Atherosclerosis Study. Stroke.. 1996;27:2216-2224.
We should not have included TIA in the sentence from the abstract quoted by Dr Lownie. All 5 patients had strokes. As shown in Table 2 of our article, 4 of the strokes occurred either during arteriography or on the next day. The fifth occurred a few days later (during the protocol-defined perioperative period) in a patient who did not go on to surgery. Thus, 1.5% of the patients had strokes or died following CEA, while 1.2% had strokes following arteriography (none died). Three additional patients had TIAs following arteriography, while 6 additional patients had TIAs following CEA. Thus, the combined rate of mortality, stroke, or TIA is 2.4% (17/721) following CEA versus 1.9% (8/415) following arteriography. The fact that 4 patients who suffered a stroke or TIA during or immediately following arteriography recovered sufficiently to undergo surgery should not lead to the conclusion that these strokes and TIAs were not significant. These are all ischemic injuries to the brain.