Möhlenkamp S, Schmermund A, Budde T, Erbel R
Cardiologisches Centrum Bethanien (CCB), Frankfurt/Main.
MMW Fortschr Med. 2007 Jun 28;149(27-28 Suppl):75-84.
The quantification of coronary calcification facilitates improved prediction of cardiovascular diseases, in particular in persons with intermediate risk. The importance of serial measurement of coronary calcium in one to two-year intervals for evaluating the course of the disease and therapeutic monitoring after risk modification is unclear. The precise quantification of the progression of arteriosclerosis could contribute to the non-invasive detection of the chronic, often subclinical development of coronary heart disease at an asymptomatic stage of the disease, long before an irreversible clinical event in the pathogenetic cascade, such as sudden cardiac death or myocardial infarction, occurs. An important prerequisite for evaluating changes in the coronary calcium load is detailed knowledge of reproducibility or variability. In addition to a rapid image acquisition time and the use of calibration phantoms, low heart rate and breathing variability, image acquisition in the late systole, overlapping layers (at the expense of radiation dose) and optimized analysis algorithms also contribute to improvement in reproducibility. The limits of variability however are, above all, dependent upon the calcium load itself. Reproducibility is on the average about 10% and thus lies below the highest expected progression, which is about 10-50% per year, depending upon the initial value and pre-existing conditions Only a few studies have identified calcium score progression as an independent predictor for later events. In several studies, calcium score progression was related to the rate of events, but was not independent of other variables. The most important determinant appears to be the calcium score itself. Other relevant determinants are age, gender, diabetes, obesity and renal failure. Whether lipid values significantly influence the progression has not been clarified.
Further studies on the natural course of coronary heart disease, particularly in the early disease stages, the determinants of progression and the extent to which the calcification progress can be modified are necessary to assess the benefit of serial score measurement for risk stratification. Until then, the repeated radiation exposure cannot be recommended outside of clinical studies.
冠状动脉钙化的量化有助于改善心血管疾病的预测，尤其是在中度风险人群中。对于评估疾病进程以及风险调整后进行治疗监测而言，每隔一到两年进行一次冠状动脉钙化的连续测量的重要性尚不清楚。动脉硬化进展的精确量化有助于在疾病无症状阶段非侵入性地检测冠心病的慢性、通常为亚临床的发展，远在发病级联中不可逆转的临床事件（如心源性猝死或心肌梗死）发生之前。评估冠状动脉钙负荷变化的一个重要前提是详细了解其可重复性或变异性。除了快速的图像采集时间和使用校准体模外，低心率和呼吸变异性、在收缩期末期进行图像采集、重叠层面（以增加辐射剂量为代价）以及优化的分析算法也有助于提高可重复性。然而，变异性的限度首先取决于钙负荷本身。平均而言，可重复性约为10%，因此低于预期的最高进展速度，后者每年约为10 - 50%，具体取决于初始值和既有状况。只有少数研究将钙评分进展确定为后续事件的独立预测因素。在一些研究中，钙评分进展与事件发生率相关，但并非独立于其他变量。最重要的决定因素似乎是钙评分本身。其他相关决定因素包括年龄、性别、糖尿病、肥胖和肾衰竭。血脂值是否会显著影响进展尚未明确。
有必要进一步研究冠心病的自然病程，尤其是在疾病早期阶段、进展的决定因素以及钙化进展可被改变的程度，以评估连续评分测量用于风险分层的益处。在此之前，除临床研究外，不建议重复进行辐射暴露。
