3042Gender differences in the prevalence of a normal IMT with increasing severity of carotid disease

Abstract

Abstract Background The ARIC group has shown that increasing IMT is only predictive of increased cardiovascular (CV) risk in males (M). Plaque is predictive of increased CV risk in both M and females (F). Purpose To determine the prevalence of a normal IMT (<1.00mm) in M and F with evidence of carotid plaque. Plaque score (PS) was used as a measure of severity of disease. Methods Our database was searched for patients with all the required data, IMT, PS and plaque area. IMT was measured with automatic edge detection software, PS was calculated using the Rotterdam method and plaque area was measured in the carotid bulb and ICA bilaterally. Only the first carotid study was used in the analysis. PS of 0–6 were used to estimate plaque severity. ANOVA and the Fisher's exact test were used to detect differences between groups. A p value of <0.05 was considered significant. Results There were 5981 patients, 3062 M and 2919 F with an average age of 62.1±11.3 years. Table I. indicates that with increasing PS, age, IMT and plaque area all increase, with a reciprocal decrease in the proportion of patients with a normal IMT. Of 3829 patients with carotid plaque 1355 (35.4%) had an IMT <1.00mm. There were clear gender differences with a much higher prevalence of a normal IMT in F with carotid plaque than M, 776 of 1772 (43.8%) versus 579 of 2057 (28.1%), p<0.0001, Fisher's exact test. This gender difference applies to most groups with increasing plaque burden except those with the most severe disease (PS “5–6”). Table 1 PS “0” PS “1” PS “2” PS “3” PS “4” PS “5–6” N 2152 896 1209 792 562 370 ANOVA Age 57.6±12.2 60.4±9.2 63.0±9.5 66.5±9.3 67.8±8.9 71.5±8.8 <0.0001 IMT 0.94±0.32 1.00±0.23 1.08±0.29 1.30±0.55 1.51±0.75 2.77±0.88 <0.0001 Plaque area 0 16.5±11.6 35.1±20.0 58.6±29.9 91.0±43.1 130.4±61.3 <0.0001 Males 1005 424 627 422 331 253 IMT <1.00mm 671 222 226 77 50 4 Percentage 66.8% 52.4% 36.0% 18.2% 15.1% 1.6% Females 1147 472 582 370 231 117 IMT <1.00mm 879 293 288 136 57 2 Percentage 76.6% 62.1% 49.5% 36.8% 24.6% 1.7% Fisher's test <0.0001 <0.005 <0.0001 <0.0001 <0.0001 NS PS = Carotid ÷ 6 segments, assigned “0” or “1” if plaque is absent or present. Conclusions Significantly more women with carotid plaque have a normal IMT. This may explain why IMT fails to be predictive of CV risk in women.