The relationship between fibrous cap status or plaque surface morphology and intraplaque hemorrhage volume over time: The PARISK Study

Background: Carotid intraplaque hemorrhage (IPH) is a strong predictor of stroke, but factors contributing to IPH development are incompletely understood. Therefore, we investigate the longitudinal relationship between a thin/ruptured fibrous cap (TRFC)/disrupted plaque surface and IPH volume. Methods: 116 ischemic TIA/stroke patients with ipsilateral carotid plaques underwent baseline and two-year follow-up MRI. IPH and fibrous cap status (thick versus TRFC) on MRI and disruption of the plaque surface (smooth versus fissure/ulceration) on CTA were assessed. Results: In the TRFC and disrupted plaque surface groups, the median IPH volume (tended) to decrease during follow-up (baseline: 97.3 IQR: [3.2-193.3] mm³ versus follow-up: 29.7 [0.0-115.1] mm³, p = 0.09, and baseline: 25.1 [0.0-166.2] mm³ versus follow-up: 11.2 [0.0-68.3] mm³, p = 0.04, respectively). In the group with a thick fibrous cap/smooth plaque surface, the median IPH volumes were zero at baseline and follow-up. The risk of IPH progression was higher in the TRFC/disrupted plaque groups (risk ratio (RR): 2.9 and 2.0, respectively) than in patients with a thick fibrous cap/smooth plaque surface. Conclusion: TIA/stroke patients with a TRFC/disrupted plaque showed a net decrease in IPH volume over time, indicating plaque healing in some patients, but patients with a TRFC/disrupted plaque are still at increased risk for IPH progression. Trial registration: ClinicalTrials.gov NCT01208025.