Suchergebnisse

Thoracic aortic calcium (TAC) has been associated with a higher prevalence of coronary arterial calcium (CAC). The purpose of this study was to assess the relationship between TAC with both incident CAC and CAC progression in a cohort from the Multi-Ethnic Study of Atherosclerosis (MESA). MESA is a prospective cohort study of 6,814 participants free of clinical cardiovascular disease at entry who underwent non-contrast cardiac computed tomography scanning at baseline examination and at a 2 year follow up. We investigated the independent association between TAC and incident CAC among those without CAC at baseline and between TAC and CAC progression among those with CAC at baseline. The final study population consisted of 5,755 (84%) individuals (62±10 years, 48% males) who had a follow up CAC score an average of 2.4 years later. Incident CAC was significantly higher among those with TAC versus without TAC at baseline (11 per 100 person years versus 6 per 100 person years). Similarly, TAC was associated with a higher CAC change (p<0.0001) in those with some CAC at baseline. In demographic & follow-up duration adjusted analysis, TAC was associated with both incident CAC (RR 1.72; P < 0.0001) as well as with a greater CAC change (RR for 1(st) and 4(th) quartiles and 95% CI: RR 2.89; −3.16, 8.95; RR 24.21; 18.25, 30.18. In conclusion, TAC is associated with incidence and progression of CAC. Detection of TAC may improve risk stratification efforts. Future clinical outcomes studies are needed to support such approach.

OBJECTIVES. To quantify and model conversion of a normal to an abnormal coronary artery calcium (CAC) scan. BACKGROUND. While absence of CAC is associated with excellent prognosis, progression to CAC>0 confers increased risk. The time interval for repeat scanning remains poorly defined. METHODS. Our study included 3,116 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) with baseline CAC=0 and follow-up scans over 10 years after baseline. Prevalence of incident CAC, defined by thresholds of either CAC>0, CAC>10, or CAC>100, was calculated and time-to-progression was derived from a Weibull parametric survival model. Warranty periods were modeled as a function of sex, race/ethnicity, cardiovascular risk, and desired yield of repeat CAC testing. We further analyzed the proportion of coronary events occurring in participants with baseline CAC=0 that precede and follow repeat CAC testing at different time intervals. RESULTS. Mean age was 58 ± 9 years, with 63% women, and mean 10-year cardiovascular risk of 14%. Prevalence of CAC>0, CAC>10, and CAC>100 was 53%, 36%, and 8% respectively at 10 years. Using a 25% testing yield (Number Needed to Scan=4) the estimated warranty period of CAC>0 varied between 3 to 7 years depending on sex and race/ethnicity. Approximately 15% progressed to CAC>10 in 5 to 8 years, while 10-year progression to CAC>100 was rare. Presence of diabetes was associated with significantly shorter warranty period, while family history and smoking had small effects. 19% of all 10-year coronary events occurred in CAC=0 prior to performance of a subsequent scan at 3–5 years, while new detection of CAC>0 preceded 55% of future events and identified individuals at 3-fold higher risk of coronary events. CONCLUSION. In a large population of individuals with baseline CAC=0, we provide a robust estimation of the CAC=0 warranty period, considering progression to CAC>0, CAC>10, and CAC>100, and impact on missed vs. detectable 10-year year CHD events. ...