Platelet deposition at carotid endarterectomy sites in humans

J R Stratton, R E Zierler, A Kazmers
1987 Stroke  
Following carotid endarterectomy, early postoperative thrombosis or late restenosis occurs in up to 20% of vessels. Both complications may be related to platelet mechanisms. To assess platelet deposition at endarterectomy sites, we injected indium-Ill labelled platelets in 24 men <30 minutes after carotid endarterectomy, with subsequent imaging 24-96 hours later. To determine if deposition decreased over time, 12 patients had follow-up studies 0.5-24 months later. For comparison, 2 control
more » ... s were studied: 1) patients with noncarotid surgery (n = 6) and 2) normal young subjects without endarterectomy and without evidence of carotid disease (n = 12). Quantitative analysis was performed using a deposition index that compared activity in operated with unoperated sites in surgical patients or activity in the right with left carotid arteries in normal subjects. Patients with recent endarterectomy had a mean deposition index of 1.7 ± 0.5 (range 1.2-3.5) compared with a similarly determined ratio of 1.1 ± 0.1 in normal subjects and 1.2 ± 0.1 in the surgical controls (both p 2 0.05 vs. acute endarterectomy). At follow-up after endarterectomy, the mean deposition index decreased to 1.0 ± 0.1, documenting reduced platelet deposition over time. We conclude that the arterial injury of carotid endarterectomy results in early platelet deposition, which is no longer present in most patients who are studied late. These findings suggest a reduction in platelet thrombus formation with time and are compatible with reendothelialization of the endarterectomized surface. This model may be useful for the in vivo assessment of therapies designed to reduce platelet accumulation following endothelial injury in humans. (Stroke 1987;18:722-727) C arotid endarterectomy involves the removal of atherosclerotic plaque with resulting exposure of a relatively large area (approximately 4-12 cm 2 ) of underlying medial collagen and adventitia. Two complications that may be related to platelet mechanisms can occur. First, early thrombotic occlusion develops in approximately 2% of vessels. 12 A second complication is late recurrent stenosis, which may be related to platelet release of factors that cause smooth muscle cell proliferation. 3 Recurrent carotid stenosis following endarterectomy occurs relatively frequently (9-18%). 4 " 8 The purpose of this study was to assess platelet deposition early and late following carotid endarterectomy in humans using indium-Ill platelet imaging. Normal subjects without surgery, as well as subjects with surgery but no endarterectomy, served as controls. Subjects and Methods Patients Twenty-four male patients, aged 47-82 years, underwent carotid endarterectomy for focal neurologic
doi:10.1161/01.str.18.4.722 pmid:3603598 fatcat:rg3o5vxd6nbrfk26aj2k3zgsju