运动应激试验达到≥10 METS 的患者的预后：SPECT 成像有用吗？
Prognosis in patients achieving ≥10 METS on exercise stress testing: was SPECT imaging useful?
机构信息
Cardiovascular Division, Department of Medicine, University of Virginia Health System, P.O. Box 800158, 1215 Lee Street, Charlottesville, VA 22908, USA.
出版信息
J Nucl Cardiol. 2011 Apr;18(2):230-7. doi: 10.1007/s12350-010-9323-2. Epub 2010 Dec 4.
BACKGROUND
The benefit of myocardial perfusion imaging (MPI) over exercise ECG stress testing alone is unclear in individuals attaining a workload of ≥10 METS. The purpose of this prospective study is to determine mortality and nonfatal cardiac events in patients at either intermediate pretest risk for CAD or patients with known CAD, achieving ≥10 METS regardless of peak exercise heart rate. The authors previously reported a low prevalence of significant ischemia in this patient cohort.
METHODS
Baseline characteristics, ECG stress test findings, and perfusion and function results from quantitative gated (99m)Tc-SPECT MPI were compared by achievement of a maximum age-predicted heart rate ≥85% in 509 consecutive patients who reached ≥10 METS. Events including all-cause and cardiac mortality, non-fatal myocardial infarction (MI), and late revascularization (>4 weeks after MPI) were prospectively collected.
RESULTS
Of the 509 patients achieving ≥10 METS, follow-up for mortality was obtained in 463 (91%). Those lost to follow-up were older and had higher rates of tobacco use. The prevalences of CAD risk factors, prior known CAD, and MPI abnormalities were higher for the 68 patients failing to reach 85% of their target heart rate. The rate of ≥10% left-ventricular (LV) ischemia by MPI remained very low irrespective of attained heart rate (0.6% (3/463)). Six (1.2%) had an LVEF < 40%. Death occurred in 12 (2.6%) patients, one of which was classified as cardiac (0.1%/year). The other 11 deaths were related to cancer. Additionally, there were three nonfatal MIs (0.7 %) and one late revascularization (0.2%). Only one of these patients had any ischemia on MPI. No cardiac event patient had exercise ST depression or ≥5% LV ischemia.
CONCLUSIONS
Thus, patients at intermediate risk for CAD or known CAD achieving ≥10 METS have a very low prevalence of ≥10% LV ischemia and very low rates of cardiac mortality, nonfatal MI, and late revascularization, irrespective of heart rate achieved. Cardiac events did not correlate with abnormalities on the index MPI study. These results suggest that patients who attain ≥10 METS during exercise stress have an excellent prognosis over an intermediate term of follow-up, regardless of peak exercise heart rate achieved. The added value of MPI to standard exercise ECG testing in this population is questionable.
背景
在达到 ≥10 梅脱（MET）的个体中，心肌灌注成像（MPI）相对于运动心电图应激测试的益处尚不清楚。本前瞻性研究的目的是确定在无论达到的峰值运动心率如何，都达到≥10MET 的中间 CAD 术前风险患者或已知 CAD 患者中的死亡率和非致死性心脏事件。作者之前报告了该患者队列中显著缺血的低患病率。
方法
比较 509 例连续达到≥10MET 的患者的基线特征、心电图应激试验结果以及定量门控（99m）Tc-SPECTMPI 的灌注和功能结果，这些患者的最大年龄预测心率≥85%。前瞻性收集包括全因和心脏死亡率、非致死性心肌梗死（MI）和晚期血运重建（MPI 后>4 周）在内的事件。
结果
在达到≥10MET 的 509 例患者中，463 例（91%）获得了死亡率随访。那些失去随访的患者年龄更大，吸烟率更高。未能达到目标心率 85%的 68 例患者的 CAD 危险因素、既往已知 CAD 和 MPI 异常的患病率更高。无论达到的心率如何，MPI 左心室（LV）缺血的发生率仍非常低（0.6%（463/7702））（6/463））。有 12 例（2.6%）患者发生死亡，其中 1 例为心脏性（0.1%/年）。其他 11 例死亡与癌症有关。此外，还有 3 例非致死性 MI（0.7%）和 1 例晚期血运重建（0.2%）。这些患者中只有 1 例有任何 MPI 缺血。没有心脏事件患者有运动 ST 段压低或≥5%LV 缺血。
结论
因此，在达到≥10MET 的中间 CAD 风险或已知 CAD 患者中，无论达到的心率如何，LV 缺血的患病率非常低，心脏死亡率、非致死性 MI 和晚期血运重建的发生率也非常低。心脏事件与指数 MPI 研究的异常无关。这些结果表明，在中期随访期间，达到运动应激试验≥10MET 的患者具有极好的预后，而与达到的峰值运动心率无关。在该人群中，MPI 对标准运动心电图检查的附加价值值得怀疑。
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