Carotid Plaque Inflammation and Morphology Is Associated with Early Stroke Recurrence
Susan Prendeville, Michael Marnane, Aine Merwick, Orla Sheehan, Niamh Hannon, Tim Grant, Peter Kelly, Niall Mulligan. Mater Misericordiae University Hospital, Dublin, Ireland; University College Dublin, Dublin, Ireland
Background: Patients with symptomatic carotid stenosis (CS) have a high risk of stroke recurrence (SR), even within the recommended 14-day time window for endarterectomy. Inflammation has been implicated as a major driver of atherosclerosis progression and plaque destabilisation, however a direct relationship with SR has not been established. The aim of this study was to investigate histological plaque features associated with early SR pre-endarterectomy, in a cohort of patients with recently-symptomatic CS.
Design: Endarterectomy tissue from 44 consecutive patients with recent transient ischaemic attack, non-disabling ischaemic stroke, or retinal embolism was analysed using a validated system for grading plaque inflammation and morphology. All patients were followed prospectively for SR occurring pre-endarterectomy and not related to surgery.
Results: SR occurred in 27.3% of patients and was significantly associated with: carotid plaque macrophage and lymphocyte infiltration (p=0.002, p=0.009 respectively), extensive (>25%) fibrous cap disruption (p=0.004), neovascularisation (p=0.04) and low plaque fibrous tissue content (p=0.003). There was no association found for intraplaque haemorrhage, lipid-rich necrotic core size, plaque calcification, foam cell content or the American Heart Association morphologic plaque classification.
On life-table analysis, actuarial pre-endarterectomy SR rates were 82.3% (CI 49.2-98.8%, 11/23 patients) in patients with extensive plaque inflammation (Oxford Plaque Study [OPS] macrophage content grade ≥3) compared to 22.2% (CI 3.5-83.4%, 1/21 patients) in those with lesser degrees of inflammation (OPS macrophage content grade <3) (log-rank p=0.009). In a multivariable Cox regression model including plaque inflammation, age, and degree of CS, plaque inflammation was the only variable independently associated with pre-endarterectomy SR (adjusted HR 9, CI 1.1-70.6, p=0.04).
Conclusions: This study demonstrates for the first time that histologically proven plaque inflammation is an important predictor of early SR in recently symptomatic CS. Histological features of plaque instability such as intraplaque haemorrhage and lipid necrotic core size were not associated with early SR, which suggests a different plaque biology. Imaging technology, which can assess plaque inflammation in vivo, as well as biomarkers, may identify the subgroup of patients at high risk for early SR, independent of degree of stenosis, who can be targeted for early intervention.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 49, Monday Morning