Background: Computed tomography (CT) allows estimation of coronary artery calcium (CAC) progression. We evaluated several progression algorithms in our unselected, population-based cohort for risk prediction of coronary and cardiovascular events.

Methods: In 3281 participants (45–74 years of age), free from cardiovascular disease until the second visit, risk factors, and CTs at baseline (b) and after a mean of 5.1 years (5y) were measured. Hard coronary and cardiovascular events, and total cardiovascular events including revascularization, as well, were recorded during a follow-up time of 7.8±2.2 years after the second CT. The added predictive value of 10 CAC progression algorithms on top of risk factors including baseline CAC was evaluated by using survival analysis, C-statistics, net reclassification improvement, and integrated discrimination index. A subgroup analysis of risk in CAC categories was performed.

Results: We observed 85 (2.6%) hard coronary, 161 (4.9%) hard cardiovascular, and 241 (7.3%) total cardiovascular events. Absolute CAC progression was higher with versus without subsequent coronary events (median, 115 [Q1–Q3, 23–360] versus 8 [0–83], P<0.0001; similar for hard/total cardiovascular events). Some progression algorithms added to the predictive value of baseline CT and risk assessment in terms of C-statistic or integrated discrimination index, especially for total cardiovascular events. However, CAC progression did not improve models including CAC_5y and 5-year risk factors. An excellent prognosis was found for 921 participants with double-zero CAC_b=CAC_5y=0 (10-year coronary and hard/total cardiovascular risk: 1.4%, 2.0%, and 2.8%), which was for participants with incident CAC 1.8%, 3.8%, and 6.6%, respectively. When CAC_b progressed from 1 to 399 to CAC_5y≥400, coronary and total cardiovascular risk were nearly 2-fold in comparison with subjects who remained below CAC_5y=400. Participants with CAC_b≥400 had high rates of hard coronary and hard/total cardiovascular events (10-year risk: 12.0%, 13.5%, and 30.9%, respectively).

Conclusions: CAC progression is associated with coronary and cardiovascular event rates, but adds only weakly to risk prediction. What counts is the most recent CAC value and risk factor assessment. Therefore, a repeat scan >5 years after the first scan may be of additional value, except when a double-zero CT scan is present or when the subjects are already at high risk.

背景：计算机断层扫描（CT）可以估算冠状动脉钙（CAC）的进展。我们在未选择的基于人群的队列中评估了几种进展算法，以预测冠心病和心血管事件的风险。

方法：在3281名参与者（45-74岁）中，直到第二次就诊之前均未患心血管疾病，测量了基线（b）和平均5.1年（5y）之后的危险因素和CTs。在第二次CT后的7.8±2.2年的随访时间内，记录了硬冠状动脉和心血管事件以及包括血管重建在内的总心血管事件。通过使用生存分析，C统计量，净重分类改进和综合辨别指数，评估了10种CAC进展算法对包括基线CAC在内的各种危险因素的附加预测价值。对CAC类别的风险进行了亚组分析。

结果：我们观察到85（2.6％）硬性冠状动脉，161（4.9％）硬性心血管病和241（7.3％）总心血管事件。有无随后的冠心病事件的绝对CAC进展更高（中位数，115 [Q1-Q3，23-360]比8 [0-83]，P <0.0001；硬/总心血管事件相似）。一些进展算法根据C统计量或综合辨别指数增加了基线CT和风险评估的预测价值，尤其是对于总的心血管事件。然而，CAC进展没有改善模型，包括CAC _5Y和5年的危险因素。对于921名双零CAC _b = CAC _5y的参与者，发现了良好的预后= 0（10年冠状动脉疾病和硬/总心血管风险：1.4％，2.0％和2.8％），分别是发生CAC事件的参与者的1.8％，3.8％和6.6％。当CAC _b从1进行到399至CAC _5Y ≥400，冠状动脉和总心血管风险刚与谁仍低于CAC受试者相比近2倍_5Y = 400。与CAC参与者_b ≥400了好大劲才冠状动脉和硬/总心血管事件（10年风险：分别为12.0％，13.5％和30.9％）的比例很高。

结论： CAC进展与冠心病和心血管事件发生率相关，但对风险预测的影响微弱。最重要的是最新的CAC值和风险因子评估。因此，第一次扫描后大于5年的重复扫描可能具有附加价值，除非存在双零CT扫描或当受试者已经处于高风险时。