Ultrasound-determined echolucency of atherosclerotic plaques was assessed prior to carotid endarterectomy/angioplasty in 57 consecutively recruited patients with high-grade internal carotid stenosis. Plasma levels of GrB were measured by enzyme immunoassay prior to surgery.
Patients with carotid atherosclerosis had significantly higher plasma levels of GrB compared to healthy controls (n = 16) (p < 0.01), with particularly high levels in those with an echolucent lesion. While there were no differences in traditional cardiovascular risk factors or CRP between those with echolucent (n = 16) and those with echogenic/heterogeneous (n = 41) plaques, the echolucent group had markedly raised plasma levels of GrB (p < 0.01). Patients with high levels of circulating granzyme B also had more ischemic lesions on cerebral MRI prior to surgery. Raised plasma levels of GrB in echolucent carotid plaques with increased frequency of cerebrovascular events suggest that GrB may be a marker of plaque instability.