Martin G S, Becker B N, Schulman G
Department of Internal Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2650, USA.
Nephrol Dial Transplant. 1998 Jul;13(7):1709-12. doi: 10.1093/ndt/13.7.1709.
Non-specific elevations of creatine kinase isoenzymes (CK-MB) and cardiac troponin-T may be seen in renal failure, confusing the diagnosis of myocardial infarction. Cardiac troponin-I (cTn-I) has been shown to be specific for myocardial damage in several disease states, but has not been prospectively evaluated in the setting of renal failure.
This prospective case series evaluated 56 patients with acute or chronic renal failure or end-stage renal disease to assess the sensitivity and specificity of cTn-I for detecting myocardial injury in this patient population. During a 6-month period, patients admitted with suspected myocardial injury by history, physical examination, and electrocardiography were evaluated. Cardiac troponin-I (cTn-I) measurements were assessed between 8 and 48 h after admission. Appropriate medical care and further cardiac testing (echocardiography, stress testing, or arteriography) was performed at the discretion of the primary physician.
Myocardial injury was diagnosed in 18/56 (32%) patients by positive cTn-I levels, while only 7/56 (13%) patients had evidence of myocardial damage by CK-MB. Twenty-one of 56 (38%) patients had indeterminate CK-MB levels and 53% of these patients demonstrated myocardial ischaemia on follow-up testing. Sixteen patients had negative cardiac studies; all of these patients had negative cTn-I levels, while seven of these 16 (44%) patients had indeterminate CK-MB measurements. All of the patients with positive cTn-I levels had positive cardiac studies. Positive troponin levels were associated with increased in-hospital mortality. Sensitivity and specificity for CK-MB were 44 and 56% respectively, and 94 and 100% for cTn-I.
These data support the use of cTn-I for diagnosing myocardial injury in patients with renal failure. Elevated cTn-I levels are associated with increased short-term mortality in renal failure patients. The accuracy of cTn-I could potentially limit unnecessary cardiac testing in renal failure patients, while the enhanced sensitivity contributes to risk stratification and aids in diagnosing true myocardial injury in this population susceptible to non-specific elevations in other muscle enzymes.
在肾衰竭患者中可见肌酸激酶同工酶（CK-MB）和心肌肌钙蛋白T的非特异性升高，这会混淆心肌梗死的诊断。心肌肌钙蛋白I（cTn-I）在多种疾病状态下已被证明对心肌损伤具有特异性，但尚未在肾衰竭患者中进行前瞻性评估。
本前瞻性病例系列研究评估了56例急性或慢性肾衰竭或终末期肾病患者，以评估cTn-I在该患者群体中检测心肌损伤的敏感性和特异性。在6个月的时间里，对因病史、体格检查和心电图检查怀疑有心肌损伤而入院的患者进行了评估。入院后8至48小时内评估心肌肌钙蛋白I（cTn-I）水平。主管医生酌情进行适当的医疗护理和进一步的心脏检查（超声心动图、负荷试验或血管造影）。
18/56（32%）的患者cTn-I水平阳性，诊断为心肌损伤，而只有7/56（13%）的患者有CK-MB提示心肌损伤的证据。56例患者中有21例（38%）的CK-MB水平不确定，其中53%的患者在后续检查中显示有心肌缺血。16例患者的心脏检查结果为阴性；所有这些患者的cTn-I水平均为阴性，而这16例患者中有7例（44%）的CK-MB测量结果不确定。所有cTn-I水平阳性的患者心脏检查结果均为阳性。肌钙蛋白水平阳性与住院死亡率增加相关。CK-MB的敏感性和特异性分别为44%和56%，cTn-I的敏感性和特异性分别为94%和100%。
这些数据支持使用cTn-I诊断肾衰竭患者的心肌损伤。cTn-I水平升高与肾衰竭患者短期死亡率增加相关。cTn-I的准确性可能会减少肾衰竭患者不必要的心脏检查，而其更高的敏感性有助于进行风险分层，并有助于诊断该易出现其他肌肉酶非特异性升高的人群中的真正心肌损伤。
