Sex Differences in Mortality Associated with Computed Tomographic Angiographic Measurements of Obstructive and Nonobstructive Coronary Artery Disease: an Exploratory Analysis

Background: Sex differences exist in the prevalence and severity of obstructive coronary artery disease (CAD). Limited data are available to explore sex differences in prognosis with coronary computed tomographic angiographic (CCTA) measurements of CAD including novel nonobstructive plaque extent.

Methods And Results: A total of 1127 consecutive patients were clinically referred to 16-slice CCTA and followed for the occurrence of all-cause death. Time to death was calculated by univariable and multivariable Cox proportional hazard models. Four-year survival (92.1%) was similar by sex (P=0.52). Women more often had no coronary stenosis (54%) as compared with men (28%) (P<0.0001). Mortality worsened for both women (P<0.0001) and men (P=0.002) by the number of vessels with > or =50% stenosis. For women, overall mortality ranged from 3.5% for no CAD to 25.0% for women with 3-vessel plus left main obstructive CAD (P<0.0001). For men, overall mortality ranged from 2.7% for no CAD to 17.4% for males with 3-vessel plus left main obstructive CAD (P=0.002). Nonobstructive disease was prevalent in women (range, 24% to 66%) and men (range, 45% to 74%) ages 45 to > or =80 years. Nonobstructive CAD extent was a significant estimator of all-cause mortality when added to a model containing pretest CAD likelihood and obstructive CAD extent (P=0.039). For men, in a risk-adjusted model including pretest CAD likelihood and obstructive CAD, the number of nonobstructive lesions was not a significant estimator of mortality (P=0.9). For women, the relative hazard for mortality, in a multivariable model, was 1.3 per nonobstructive lesion (P=0.003), including pretest CAD likelihood and obstructive CAD as covariates. For women, risk-adjusted median mortality ranged from 2.9% to 10.9% for none to > or =4 nonobstructive lesions (P<0.0001).

Conclusions: Based on our preliminary analyses, CCTA obstructive and nonobstructive CAD adds incremental value to clinical assessment for risk stratification. Moreover, the extent of nonobstructive CAD by CCTA predicts mortality in women but not in men and may be helpful to optimize therapeutic strategies for women.