BACKGROUND Several recent trials have evaluated invasive versus medical therapy for stable ischemic heart disease. Importantly, patients with significant left main coronary stenosis (LMCS) were excluded from these trials. In the ISCHEMIA trial, these patients were identified by a coronary CT angiogram (CCTA), which adds time, expense, and contrast exposure. We tested whether a coronary artery calcium scan (CACS), a simpler, less expensive test, could replace CCTA to exclude significant LMCS. METHODS We hypothesized that patients with ≥50% LMCS would have a LM CACS score > 0. As a corollary, we postulated that a LM CACS = 0 would exclude patients with LMCS. To test this, we searched Intermountain Healthcare's electronic medical records database for all adult patients who had undergone non-contrast cardiac CT for quantitative CACS scoring prior to invasive coronary angiography (ICA). Patients aged <50 and those with a heart transplant were excluded. Cases with incomplete (qualitative) angiographic reports for LMCS and those with incomplete or discrepant LM CACS results were reviewed and reassessed blinded to CACS or ICA findings, respectively. RESULTS Among 669 candidate patients with CACS followed by ICA, 36 qualifying patients were identified who had a quantitative CACS score and LMCS ≥ 50%. Their age averaged 71.8 years, and 81% were men. Angiographic LMCS averaged 72% (range 50%-99%). Median time between CACS and ICA was 6 days. Total CACS score averaged 2,383 Agatston Units (AU), range 571-6,636. LM CACS score averaged 197 AU, range 31-610. Importantly, no LMCS patient had a LM CACS score of 0 vs 57% (362/633) of non-LMCS controls (P < .00001). CONCLUSIONS Our results support the hypothesis that an easily administered, inexpensive, low radiation CACS can identify a large subset of patients with a very low risk of LMCS who would not have the need for routine CCTA. Using CACS to exclude LMCS may efficiently allow for safe implementation of an initial medical therapy strategy of patients with stable ischemic heart disease in clinical practice. These promising results deserve validation in larger data sets.

中文翻译：

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简化临床实践的 ISCHEMIA 试验算法：使用冠状动脉钙扫描识别左主干冠状动脉疾病。

背景 最近的几项试验评估了稳定缺血性心脏病的侵入性治疗与药物治疗。重要的是，这些试验排除了显着左主干冠状动脉狭窄 (LMCS) 的患者。在 ISCHEMIA 试验中，这些患者通过冠状动脉 CT 血管造影 (CCTA) 进行识别，这增加了时间、费用和造影剂暴露。我们测试了冠状动脉钙化扫描 (CACS)，一种更简单、更便宜的测试，是否可以取代 CCTA 以排除重要的 LMCS。方法 我们假设 LMCS ≥ 50% 的患者的 LM CACS 评分 > 0。作为推论，我们假设 LM CACS = 0 将排除 LMCS 患者。为了测试这一点，我们搜索了 Intermountain Healthcare s 电子病历数据库，适用于在侵入性冠状动脉造影 (ICA) 之前接受非对比心脏 CT 进行定量 CACS 评分的所有成年患者。年龄 <50 岁的患者和心脏移植患者被排除在外。LMCS 血管造影报告不完整（定性）的病例和 LM CACS 结果不完整或不一致的病例分别在不知道 CACS 或 ICA 结果的情况下进行审查和重新评估。结果 在 669 名 CACS 后继 ICA 的候选患者中，确定了 36 名具有定量 CACS 评分和 LMCS ≥ 50% 的合格患者。他们的平均年龄为 71.8 岁，其中 81% 是男性。血管造影 LMCS 平均为 72%（范围为 50%-99%）。CACS 和 ICA 之间的中位时间为 6 天。CACS 总分平均为 2,383 Agatston Units (AU)，范围为 571-6,636。LM CACS 得分平均为 197 AU，范围为 31-610。重要的是，没有 LMCS 患者的 LM CACS 评分为 0，而非 LMCS 对照组为 57% (362/633) (P < .00001)。结论 我们的研究结果支持这样一个假设，即易于管理、价格低廉、低辐射的 CACS 可以识别大量不需要常规 CCTA 的 LMCS 风险极低的患者。使用 CACS 排除 LMCS 可以有效地允许在临床实践中安全实施稳定型缺血性心脏病患者的初始药物治疗策略。这些有希望的结果值得在更大的数据集中验证。低辐射 CACS 可以识别大部分不需要常规 CCTA 的 LMCS 风险非常低的患者。使用 CACS 排除 LMCS 可以有效地允许在临床实践中安全实施稳定型缺血性心脏病患者的初始药物治疗策略。这些有希望的结果值得在更大的数据集中验证。低辐射 CACS 可以识别大部分不需要常规 CCTA 的 LMCS 风险非常低的患者。使用 CACS 排除 LMCS 可以有效地允许在临床实践中安全实施稳定型缺血性心脏病患者的初始药物治疗策略。这些有希望的结果值得在更大的数据集中验证。