Sex differences of high-risk carotid atherosclerotic plaque with less than 50% stenosis in asymptomatic patients: an in vivo 3T MRI study

Abstract

Background and purpose: Men have a greater prevalence of high-risk carotid plaque features associated with stroke compared with women who have ≥50% stenosis, but little is known about these features in less significantly stenotic carotid arteries. This study aims to evaluate sex differences in complicated carotid plaque features in asymptomatic patients with <50% stenosis.

Materials and methods: Ninety-six patients (50 men, 46 women) with <50% carotid stenosis on MRA who had been referred for analysis of contralateral >50% carotid stenosis were included. The associations between sex and plaque features as identified by 3T MR carotid plaque imaging were examined by using logistic and linear regression models controlling for demographic characteristics, MRA stenosis, and the presence of contralateral plaque features.

Results: The presence of a thin/ruptured fibrous cap (16% versus 2%, adjusted odds ratio = 8.57, P = .047), IPH (24% versus 6%, adjusted odds ratio = 4.53, P = .027), and American Heart Association type VI plaque (26% versus 6%, adjusted odds ratio = 5.04, P = .017) was significantly higher in men than in women. These associations remained significant following adjustment for contralateral plaque features. Men demonstrated a larger percentage volume of LR/NC (median, 1.66% versus -0.21%; P < .01). Calcification was not significantly associated with sex.

Conclusions: There is a sex difference of higher risk carotid plaque features during the early stage of disease seen in patients recruited for MR imaging evaluation of contralateral moderate-to-severe stenosis. Given the potential of using LR/NC without or with IPH to monitor therapy, these results indicate the possible importance of sex-based management in patients with asymptomatic carotid atherosclerosis across all stages of carotid stenosis.

Figures

Fig 1.

A 75-year-old man with asymptomatic mild left carotid artery stenosis and complex carotid plaque. A, Maximum intensity projections from contrast-enhanced MRA show irregular narrowing of the distal left common carotid artery with stenosis of 33% diameter. The horizontal line indicates the level of transverse carotid plaque imaging. B, The chevrons demonstrate a large nonenhancing LR/NC region on CE-T1WI. Much of the LR/NC contains IPH seen as bright on IR-FSPGR and TOF. Last, a fibrous cap rupture with an ulcer penetrating into the hemorrhagic LR/NC is seen as depicted by the thin arrow. C, The large LR/NC is yellow, and calcifications are white on this volume-reformatted image generated from the multicontrast carotid plaque series. The total volume of LR/NC is 137 mL, and the percentage of the maximum area of LR/NC is 47%. Such large-volume LR/NC regions are frequently associated with other complex carotid plaque features such as IPH and/or fibrous cap rupture that correspond to American Heart Association type VI carotid plaque, which was found to occur significantly more often in men than in women.

Fig 2.

A 74-year-old woman with asymptomatic mild right carotid stenosis and minimal LR/NC. A, Maximum intensity projection from contrast-enhanced MRA shows smooth narrowing of the distal right common carotid artery and proximal right internal carotid artery with a stenosis of 41% diameter. The horizontal line indicates the level of transverse carotid plaque imaging. B, The chevron demonstrates a small nonenhancing LR/NC region on CE-T1WI and IR-FSPGR. No high signal intensity on IR-FSPGR or TOF is seen to suggest IPH. The thin arrow demonstrates a thick and intact fibrous cap overlying the small deep LR/NC. These findings correspond to American Heart Association types IV and V carotid plaque. C, Two very small regions of LR/NC are seen as yellow in the volume-reformatted image generated from the multicontrast carotid plaque series. The total volume of LR/NC is 2 mL, and the percentage of maximum area of LR/NC is 8%. Women showed significantly smaller volumes of LR/NC and a significantly lower incidence of American Heart Association type VI carotid plaque compared with men in this study.