Heydari Bobak, Juan Yu-Hsiang, Liu Hui, Abbasi Siddique, Shah Ravi, Blankstein Ron, Steigner Michael, Jerosch-Herold Michael, Kwong Raymond Y
From the Noninvasive Cardiovascular Imaging Program, Division of Cardiovascular Medicine, and Radiology, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA (B.H., Y.-H.J., H.L., S.A., R.S., R.B., M.S., M.J.-H., R.Y.K.); Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan (Y.-H.J.).
Circ Cardiovasc Imaging. 2016 Apr;9(4):e004136. doi: 10.1161/CIRCIMAGING.115.004136.
Diabetics remain at high risk of cardiovascular disease and mortality despite advancements in medical therapy. Noninvasive cardiac risk profiling is often more difficult in diabetics owing to the prevalence of silent ischemia with unrecognized myocardial infarction, reduced exercise capacity, nondiagnostic electrocardiographic changes, and balanced ischemia from diffuse epicardial coronary atherosclerosis and microvascular dysfunction.
A consecutive cohort of 173 patients with diabetes mellitus (mean age, 61.7±11.9 years; 37% women) with suspected myocardial ischemia underwent stress perfusion cardiac magnetic resonance imaging. Patients were evaluated for adverse cardiac events after cardiac magnetic resonance imaging with mean follow-up time of 2.9±2.5 years. Mean hemoglobin A1c for the population was 7.9±1.8%. Primary end point was a composite of cardiac death and nonfatal myocardial infarction. Diabetics with no inducible ischemia (n=94) experienced an annualized event rate of 1.4% compared with 8.2% (P=0.0003) in those with inducible ischemia (n=79). Diabetics without late gadolinium enhancement or inducible ischemia had a low annual cardiac event rate (0.5% per year). The presence of inducible ischemia was the strongest unadjusted predictor (hazard ratio, 4.86; P<0.01) for cardiac death and nonfatal myocardial infarction. This association remained robust in adjusted stepwise multivariable Cox regression analysis (hazard ratio, 4.28; P=0.02). In addition, categorical net reclassification index using 5-year risk cutoffs of 5% and 10% resulted in reclassification of 43.4% of the diabetic cohort with net reclassification index of 0.38 (95% confidence interval, 0.20-0.56; P<0.0001).
Stress perfusion cardiac magnetic resonance imaging provided independent prognostic utility and effectively reclassified risk in patients with diabetes mellitus referred for ischemic assessment. Further evaluation is required to determine whether a noninvasive imaging strategy with cardiac magnetic resonance imaging can favorably affect downstream outcomes and improve cost-effectiveness of care in diabetics.
尽管医学治疗取得了进展，但糖尿病患者仍然面临心血管疾病和死亡的高风险。由于无症状性缺血伴未被识别的心肌梗死的患病率较高、运动能力下降、心电图变化无诊断价值以及弥漫性心外膜冠状动脉粥样硬化和微血管功能障碍导致的平衡缺血，糖尿病患者的无创心脏风险评估往往更加困难。
连续纳入173例疑似心肌缺血的糖尿病患者（平均年龄61.7±11.9岁；37%为女性），进行负荷灌注心脏磁共振成像检查。在心脏磁共振成像检查后对患者进行不良心脏事件评估，平均随访时间为2.9±2.5年。该人群的平均糖化血红蛋白为7.9±1.8%。主要终点是心源性死亡和非致命性心肌梗死的复合终点。无诱导性缺血的糖尿病患者（n=94）的年化事件发生率为1.4%，而有诱导性缺血的患者（n=79）为8.2%（P=0.0003）。无延迟钆增强或诱导性缺血的糖尿病患者的年度心脏事件发生率较低（每年0.5%）。诱导性缺血的存在是心源性死亡和非致命性心肌梗死最强的未调整预测因素（风险比，4.86；P<0.01）。在调整后的逐步多变量Cox回归分析中，这种关联仍然很强（风险比，4.28；P=0.02）。此外，使用5%和10%的5年风险临界值的分类净重新分类指数导致43.4%的糖尿病队列被重新分类，净重新分类指数为0.38（95%置信区间，0.20-0.56；P<0.0001）。
负荷灌注心脏磁共振成像为接受缺血评估的糖尿病患者提供了独立的预后价值，并有效地重新分类了风险。需要进一步评估以确定心脏磁共振成像的无创成像策略是否能有利地影响下游结局并提高糖尿病患者护理的成本效益。
