Implications of Gender Difference in Coronary Calcification as Assessed by CT Coronary Angiography

Background Arterial calcium as measured by 64-slice computed tomography coronary angiography (64-CT) is a reliable predictor of cardiovascular disease risk. Lipid-rich plaques with lower degrees of calcification may pose greater risk for adverse coronary events than more stabilized calcified plaques as a result of the increased risk of plaque rupture, migration, and subsequent acute coronary syndrome. We sought to examine coronary artery calcium scores as measured via 64-CT to assess the extent of calcification and plaque distribution in women compared to men. Methods A total of 138 patients referred for 64-CT were evaluated. Computerized tomographic angiography was performed using the GE LightSpeed VCT. Subgroup analysis comparing male and female data (including demographic data) was performed. All major coronary arteries were analyzed for coronary stenosis/plaque characterization as well as total vessel calcium (Agatston) score quantification. Patient demographics and coronary risk factors were recorded. Results A total of 552 coronary arteries were evaluated in 138 patients (85 men, 53 women). The average age for females was 64.4 ± 10.8 years and for males 60.0 ± 12.8 years. The only demographic/cardiovascular risk factor in which the difference between men and women was significant was smoking history, where 23.5% of men had a history of smoking while only 9.6% of females endorsed having a smoking history ( P < 0.044). On comparison of all total vessel calcium scores, males had a higher total mean calcium score than females in each individual vessel. The results were as follows for males versus females, respectively: left main total vessel calcium score 46.49 versus 16.71 ( P = 0.167); left anterior descending 265.21 versus 109.6 ( P < 0.003); left circumflex 130.5 versus 39.7 ( P < 0.004); and right coronary 213.5 versus 73.8 ( P < 0.01). The odds of having a total calcium score >100 (versus not) was 3.62 times greater in males relative to females, given that all the other cardiovascular risk factors are adjusted for (95% confidence interval: 1.37-9.54). On average, men had an average of 2.1 ± 1.5 epicardial vessels with a calcium score ≥11 compared to 1.3 ± 1.4 for women ( P < 0.005). Conclusion There are clear differences between males and females regarding total vessel calcium scores and therefore risk of future adverse coronary events. Males tended to have higher average calcium scores in each coronary artery than females with a greater tendency to have multiple vessel involvement. Using this information, more large-scale, randomized controlled studies should be performed to correlate differences in the extent of coronary calcification with the observed variance in clinical presentation during coronary events between males and females as a means to potentially establish gender-specific therapeutic regimens.