De Rotte A, Truijman M, Van Dijk A, Liem M, Schreuder F, Van Der Kolk A, et al. Plaque Components in Symptomatic Moderately Stenosed Carotid ArteriesRelated to Cerebral Infarcts: The Plaque At RISK Study. Stroke. 2015
The carotid ultrasound is the one part of the stroke workup truly essential due to the established evidence-based guidelines regarding carotid revascularization in symptomatic carotid stenosis. The selection of candidates for carotid revascularization however is currently decided by medical professionals picking a number (i.e. >70%) that they feel is high enough to warrant a procedure for patients with strokes on the ipsilateral side of the carotid stenosis (symptomatic carotid stenosis). A better question to ask is whether the carotid plaque, regardless of degree of stenosis, has characteristics that make it a “dangerous” plaque at risk of rupturing again. The group out of the Netherlands asked this question and decided to assess carotid plaques with 3 Tesla MRI scanners to assess whether particular plaque components (intraplaque hemorrhage (IPH) or thin/ruptured fibrous cap (TRFC)) were associated with the presence of infarcts on MRI.
The group analyzed 101 patients with symptomatic 30-69% carotid artery stenosis who underwent a 3T MRI of the carotid arteries and the brain within 45 days of symptom onset. They used two different readers blinded to the brain MRI results, to analyze the carotid artery MRI and examine them for IPH and TRFC. They found that IPH was present in 40 out of the 101 patient with 55% having infarcts on the side of the carotid plaque however in the patients without IPH, 41% had infarcts on the symptomatic side (p= 0.22). A TRFC was present in 49 out of 86 patients (15 patients could not have fibrous cap assessed), with 45% having infarcts on the side of the symptomatic carotid however this was not significantly different from the 49% in the 37 patients with a thick fibrous cap. The significance did not change when only cortical (instead of both subcortical and cortical) infarcts were taken into account.
Though the data was a bit underwhelming in terms of significance, the study still provides important findings and implications regarding the future of plaque analysis in determining who would be a good candidate for carotid revascularization. Perhaps an imaging method besides MRI may be better suited for identifying plaque components or perhaps the best series for analyzing these components on MRI has not been defined as of yet. Regardless, the thought process demonstrated by the authors is an ideal one that all practitioners should follow rather than simply letting a number dictate treatment.