Site and pathogenesis of infarcts associated with carotid endarterectomy.

Abstract

We analyzed perioperative strokes in 658 carotid endarterectomies with the purpose of explaining the pathogenesis from the morphologic aspect of the infarct on cerebral computed tomograms. All endarterectomies were performed with continuous electroencephalographic monitoring. Of the 42 ischemic strokes (6.4% of all endarterectomies), 34 could be studied. Seven infarcts were hemodynamically induced (five watershed infarcts, two patients with bilateral ischemia); all seven occurred during surgery. Twenty-three of the remaining 27 infarcts were within the territory of the middle cerebral artery (20) or anterior cerebral artery (three) and were probably of thromboembolic origin; 13 of these 23 occurred during surgery (57%). If intraoperative stroke was heralded by permanent electroencephalographic changes, these were not related to the moment of cross-clamping. In four patients the computed tomogram was normal. We believe these facts favor the hypothesis that thromboembolism is the most important factor in the pathogenesis of perioperative stroke associated with carotid endarterectomy under conditions of optimal cerebral monitoring. (Stroke 1989;20:324-328)

Small Centrum ovale Infarcts – A Pathological Study

“…It might also be consistent with a borderzone distribution, for experiments have shown that artificial microemboli distribute preferentially to borderzones in autopsy human brains [23], and also that microthrombi are demonstrated pathologically in regions of cortical borderzone infarctions [24]. Perioperative borderzone infarction may also complicate carotid endarterectomy [25, 26], the majority of which are likely embolic [27, 28]. …”

“…The distribution of SCOIs in this study, based on accurate PM coronal brain slice examination, suggests that the majority lie at the junction of the anterior cerebral artery and middle cerebral artery supply zones. Such a distribution suggests hemodynamic mechanisms [31], ICA occlusive disease [32, 33, 34]or, as has been discussed, embolism [23, 24, 25, 26, 27, 28]. There is no obvious reason why small SVD-related pathology should cluster at arterial borderzones.…”

Timing of Clinically Significant Microembolism after Carotid Endarterectomy

“…Most strokes occur ipsilateral to the surgical artery, are probably caused by thromboembolism [2,6,7,8,9,10] and occur intra-operatively or in the immediate post-operative hours [6, 8] . Of concern, peri-operative stroke is often not anticipated at the time of surgical closure [11].…”

Microembolic Watershed Infarction Complicating Carotid Endarterectomy

“…As the majority of perioperative cerebral ischaemic events are likely to be thromboembolic [3,4], investigation using techniques such as transcranial Doppler (TCD) ultrasonic embolus detection may provide important insights into the pathogenesis and prevention of perioperative stroke.…”