Impact of Aortic Valve Calcification Measured by Multidetector Computed Tomography on Survival in Patients With Aortic Stenosis: Results of an International Registry
Does aortic valve calcification (AVC) on computed tomography (CT) predict mortality risk in patients with aortic stenosis (AS)?
This study evaluated 794 patients with at least mild AS by echocardiography undergoing noncontrast CT at three centers. AVC severity and AVC density were measured, and multivariable analysis examined the relationship of AVC, hemodynamic AS severity, and clinical characteristics. The primary endpoint was survival on medical treatment, with any patients undergoing aortic valve replacement (AVR) censored at the time of AVR. Secondary endpoints included survival regardless of AVR.
Mean follow-up was 3.1 ± 2.6 years, with 440 AVRs and 194 deaths. High AVC density was associated with increased aortic valve peak velocity, higher mean gradient, and decreased valve area (p < 0.001 for each). Severe versus nonsevere AVC was associated with reduced 5-year survival in those treated medically (41 ± 6% vs. 78 ± 6%, p < 0.001). On multivariate analysis, severe AVC (hazard ratio [HR], 1.75; 95% confidence interval [CI], 1.04-2.92; p = 0.03) and severe AVC density (HR, 2.44; 95% CI, 1.37-4.37; p = 0.002) were independently associated with increased mortality in patients treated medically. For survival regardless of AVR, both severe AVC (HR, 1.71; 95% CI, 1.12-2.62; p = 0.01) and severe AVC density (HR, 2.22; 95% CI, 1.37-4.37; p = 0.002) remained associated with increased mortality; both of these variables remained statistically significant when adjusted for coronary artery calcium score in the subset with this available (p < 0.05 for each). Multivariable analysis observed that severe AVC density was associated with increased mortality in subgroups with severe AS (HR, 2.79; p = 0.002) and without severe AS (HR, 2.93; p = 0.008).
Severe AVC and AVC density on CT are independently associated with mortality in patients with at least mild AS.
In patients with at least mild AS, the presence of severe AVC on noncontrast CT provides prognostic data that are incremental to clinical variables and AS severity by echocardiography. Interestingly, severe AVC density is associated with increased mortality in patients with severe AS by echocardiography, as well as patients without severe AS. In patients without baseline severe AS, it is possible that severe AVC may identify those at higher risk of AS progression, or may represent a marker of mortality risk from nonvalvular causes. The strong independent relationship between AVC and mortality in patients with at least mild AS suggests that AVC may be useful to risk stratify patients, although it remains unclear whether AVC severity is helpful in identifying patients most likely to benefit from AVR.
Keywords: Multivariate Analysis, Multidetector Computed Tomography, Confidence Intervals, Coronary Vessels, Hemodynamics, Echocardiography, Calcium
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