Askew J Wells, Miller Todd D, Araoz Philip A, Breen Jerome F, Hodge David O, Gibbons Raymond J
Division of Cardiovascular Diseases, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
Mayo Clin Proc. 2008 Jan;83(1):17-22. doi: 10.4065/83.1.17.
To determine whether asymptomatic patients with atherosclerosis, indicated by the presence of coronary artery calcium on electron beam computed tomography, are at enough risk for progression of disease to justify a repeated stress single-photon emission computed tomography (SPECT) examination after an initial normal to low-risk perfusion study.
We retrospectively identified patients who had abnormal results on electron beam computed tomography (coronary artery calcium score > 0) and normal to low-risk results on SPECT (defined as a summed stress score of 0-3) within a 3-month period from January 1, 1995, to October 31, 2002. Of the 504 identified patients, 285 remained after exclusion criteria were applied. Of the 285 patients, 69 (mean +/- SD age, 58.2 +/- 7.6 years; 91% male) underwent at least 1 repeated myocardial perfusion SPECT imaging study within 4 years of their initial assessment as normal or at low risk without recurrence of symptoms. The value of repeated SPECT imaging was assessed by detection of a substantial change in the repeated SPECT study and by documentation of a clinical event (death, nonfatal myocardial infarction, or revascularization). Follow-up was 100% complete at a mean of 4.3 +/- 1.6 years.
Only 4 patients (6%) had a substantial progression in their SPECT risk category; substantial changes on the SPECT scans occurred only in patients with a coronary artery calcium score greater than 100. Three patients underwent revascularization, yielding a 5-year rate for survival free of revascularization of 94% (95% confidence interval, 88%-100%). No deaths or nonfatal myocardial infarctions were reported.
The principal findings of this study indicate that asymptomatic patients with initial normal or low-risk results from stress SPECT performed because of abnormal coronary artery calcium scores who remain asymptomatic are at low risk of death, myocardial infarction, or coronary revascularization. Three patients underwent revascularization by percutaneous coronary intervention despite the absence of symptoms. A substantial change in SPECT results (defined as progression from normal or low-risk summed stress score to intermediate- or high-risk summed stress score) affected 6% of patients and was not associated with any adverse hard events (nonfatal myocardial infarction or death).
确定电子束计算机断层扫描显示存在冠状动脉钙化的无症状动脉粥样硬化患者，其疾病进展风险是否足以证明在初次灌注研究正常至低风险后重复进行负荷单光子发射计算机断层扫描（SPECT）检查是合理的。
我们回顾性地确定了1995年1月1日至2002年10月31日这3个月内电子束计算机断层扫描结果异常（冠状动脉钙化评分>0）且SPECT结果正常至低风险（定义为负荷总分0 - 3）的患者。在确定的504例患者中，应用排除标准后剩余285例。在这285例患者中，69例（平均±标准差年龄，58.2±7.6岁；91%为男性）在初次评估为正常或低风险且无症状复发的4年内至少接受了1次重复心肌灌注SPECT成像研究。通过检测重复SPECT研究中的显著变化以及记录临床事件（死亡、非致命性心肌梗死或血运重建）来评估重复SPECT成像的价值。平均随访4.3±1.6年，随访率达100%。
仅4例患者（6%）的SPECT风险类别有显著进展；SPECT扫描的显著变化仅发生在冠状动脉钙化评分大于100的患者中。3例患者接受了血运重建，5年无血运重建生存率为94%（95%置信区间，88% - 100%）。未报告死亡或非致命性心肌梗死。
本研究的主要发现表明，因冠状动脉钙化评分异常而进行的负荷SPECT检查初次结果正常或低风险且无症状的患者，发生死亡、心肌梗死或冠状动脉血运重建的风险较低。3例患者尽管无症状仍接受了经皮冠状动脉介入血运重建。SPECT结果的显著变化（定义为从正常或低风险负荷总分进展为中或高风险负荷总分）影响了6%的患者，且与任何不良硬性事件（非致命性心肌梗死或死亡）无关。
