Investigation Of Carotid Plaque Stability And Vascular Remodeling In Hypertension Patients Using MR Imaging

Objective:To investigate carotid plaque stability and vascular remodeling in the patints with primary hypertension, using high-resolution magnetic resonance imaging (HRMRI).Materials and methods:1. To study the relationship between carotid remodeling index (CRI) and plaque composition and clinical factors.74 cases (74 plaques) in hypertension with maximum wall thickness (MaxWT) of internal carotid artery≥ 1.5 mm, divided into symptomatic group (n= 40) and asymptomatic group (n= 34).2. To investigate the natural history of carotid plaque composition and morphology. Using HRMRI reviewed 65 cases (65 plaques) without new ischemic stroke, follow-up period≥ 0.5 years, MaxWT of internal carotid artery≥ 1.5 mm on the baseline, divided into stable plaque group (n= 18) and unstable plaque group (n= 47). The Log Rank test and Cox regression analysis was performed to test the difference of plaque morphology related to time between two groups.3. To investigate the relationship between ACE I/D genotype and plaque composition, morphology and clinical symptoms.75 cases (75 plaques) in hypertension with MaxWT of internal carotid artery≥ 1.5 mm, according to the ACE I/D genotype, divided into Ⅱ group (n= 37) and ID/DD group (n= 38).Results:1. CRI was demonstrated a good interobserver agreement. A CRI of 2.00 was determined as the most reliable cutoff value for predicting symptomatology, and the sensitivity and specificity were 72.5% and 58.8%, respectively (AUC= 0.629, P= 0.058). A CRI of 2.34 was determined as the most reliable cutoff value for predicting fibrous cap rupture, and the sensitivity and specificity were 72.7%,65.1%, respectively (AUC= 0.716, P= 0.023). CRI was positively correlated with plaque vulnerability (r= 0.248, P= 0.033). Taking ACEI/ARB may decrease the CRI (P< 0.05).2. The longer history of hypertension, the higher incidence of unstable plaque. Without new ischemic stroke, carotid plaque composition does not significantly change over 1.84 (0.52-3.82) years period. The wall area and NWI of stable plaque increased by 5.21% and 1.64% per year, the MaxWT, wall area and plaque level CSVA of unstable plaque increased faster by 2.03%,5.43% and 4.92% per year (P< 0.05). CRI does not significantly change during the follow-up period (P> 0.05).3. ID/DD genotype significantly occurs in patients with ischemic stroke (P< 0.05). Taking ACEI/ARB, the CRI of ID/DD genotype decreased significantly (P< 0.05), distal CSVA increased, compared to Ⅱ genotype (P= 0.066).Conclusion:The stability and vascular remodeling of carotid plaque in primary hypertension may have the following features:1. The degree of outer remodeling is significantly related to the ischemic stroke, fibrous cap status, plaques composition. The CRI detected by HRMRI is reliable to predict the plaque stability and ischemic evens.2. During the 1.8 years period, without new symptoms, plaque composition could be remained, the presence of IPH and fibrous cap status change in a minority of cases. In the natural course, unstable plaque increased faster than the stable plaque, mainly for the increase of MaxWT and wall area, without the change of CRI.3. ACE I/D genotype is associated with ischemic stroke, taking ACEI/ARB may improve the vascular compliance in the ID/DD genotype significantly.