The prevalence of false-positive cardiac troponin I in ED patients with rhabdomyolysis

OBJECTIVE: Cardiac troponin I (cTnI) is considered the most specific marker of cardiac muscle injury. We encountered several patients with rhabdomyolysis and elevated cTnI, although they did not otherwise have evidence of cardiac injury. We determined the prevalence of false-positive cTnI in emergency department (ED) patients with rhabdomyolysis. METHODS: We conducted a retrospective cohort study of ED patients admitted with a diagnosis of rhabdomyolysis. Patients were included in the study if they had a serum creatine kinase (CK) of 1000 U/L or greater and at least one serum cTnI determination. Patients with positive cTnI were considered true positives if they had either electrocardiography (EKG) or echocardiography abnormalities; false positives if both the EKG and the echocardiography were considered normal; or indeterminate if they did not have both an EKG and an echocardiogram. The primary outcome of the study was the prevalence of false-positive cTnI. Secondary outcomes included risk stratification by cocaine use, myoglobinuria, and renal failure and correlation of peak CK and troponin levels. RESULTS: One hundred nine patients were included in the final analysis; 55 (50%) patients had a positive cTnI. Of the 55 patients with positive cTnI, 32 (58%) were true positives, 18 (33%) were false positives, and 5 (9%) were indeterminate. The prevalence of false-positive cTnI was 17% (18/109, 95% confidence interval 0.10-0.25). There was no association between false-positive cTnI and cocaine use, renal failure, or myoglobinuria. There was poor correlation between peak CK and peak cTnI levels (r = -.08, 95% confidence interval -0.34 to 0.19). CONCLUSION: The prevalence of false-positive cTnI in ED patients with rhabdomyolysis is 17%.     

CT肺动脉栓塞指数评价急性肺栓塞患者右心功能

目的 探讨CT肺动脉栓塞指数(PAOI)半定量评价急性肺栓塞(APE)右心功能的价值。方法 回顾性分析经CT肺血管成像(CTPA)确诊的、无严重基础心肺疾病的APE患者117例,依据肺动脉内栓子阻塞的部位及程度计算PAOI。根据PAOI<30%、30%~50%和＞50%将APE患者分为轻、中和重度三组,分析各组的右心功能参数的差异。结果 入选患者中,轻度组65例,中度组32例,重度组20例。轻度与中度组比较,差异有统计学意义的指标有RV_d、LV_d、RV_d/LV_d、RV_s、LV_s、RV_s/LV_s、MPA、LPA、IVSD、IVCR;轻度组与重度组比较,差异有统计学意义的指标有RV_d、LV_d、RV_d/LV_d、RV_s、LV_s、RV_s/LV_s、SVC、MPA、RPA、LPA、IVSD、IVCR、AZR;中度组与重度组比较,差异有统计学意义的指标有LV_d、RV_d/LV_d、RV_s/LV_s。结论 APE患者的PAOI可以反映右心功能情况,并有助于及时确认APE的病情程度。     

The incidence and prognostic significance of elevated cardiac troponins in patients with submassive pulmonary embolism

Although the incidence and prognostic significance of elevated cardiac troponins are known in patients with massive pulmonary embolism (PE), few studies have addressed this issue in patients with hemodynamically stable, submassive PE, who comprise the majority of patients presenting with PE. This prospective cohort study was, therefore, designed to determine the incidence and prognostic significance of elevated cardiac troponins in patients with submassive PE. Consecutive patients with acute, symptomatic, submassive PE that was confirmed by objective diagnostic testing were studied. All patients received treatment with either unfractionated heparin or fondaparinux followed by a coumarin derivative and underwent clinical follow-up for 3 months. Cardiac troponin I (cTnI) levels were measured within 24 h of clinical presentation. An elevated cTnI was defined as > 0.5 microg L(-1) and indicated myocardial injury. Major myocardial injury, that is associated with myocardial infarction, was defined by a cTnI > 2.3 microg L(-1). The clinical outcomes were recurrent venous thromboembolism and all-cause death. In 458 patients with submassive PE, the incidence of cTnI > 0.5 microg L(-1) was 13.5%[95% confidence interval (CI): 10.4-16.7], and the incidence of cTnI > 2.3 microg L(-1) was 3.5% (95% CI: 2.0-5.6). An elevated cTnI > 0.5 microg L(-1) was associated with an increased risk of all-cause death [odds ratio (OR) = 3.5; 95% CI: 1.0-11.9], but did not appear to confer an increased risk of recurrent venous thromboembolism (OR = 1.1; 95% CI: 0.2-4.9). In patients who present with submassive PE, an elevated cTnI occurs in about one in seven patients and is associated with a 3.5-fold increased risk of all-cause death.     

Outcome of patients with elevated cardiac troponin I level after mild trauma

The objective of this study was to evaluate whether increased c-Tnl in patients suffering from mild trauma without cardiac disease may be prognostic for future cardiac events. Consecutive patients suffering from mild trauma were recruited and evaluated for levels of creatinine, creatine-kinase (CK) and c-Tnl. Patients with elevated c-Tnl were selected and followed up for six months for cardiac events (cardiac death, Myocardial Infarction, Acute Coronary Syndromes, cardiac syncope, pacemaker or Intracardiac Device Implantation, Percutaneous Cardiac Intervention, and aortic-coronary bypass). No relationship was found between levels of c-Tnl and CK or creatinine. Patients with elevated c-Tnl suffered significantly more of cardiac events than did patients with normal levels of c-Tnl. Increased of c-Tnl in patients experiencing mild trauma but not cardiac diseases may be a preclinic index of future cardiac disease.     

肌钙蛋白I与冠状动脉病变的关系

目的 探讨血清肌钙蛋白Ⅰ（TnⅠ)与冠脉病变稳定性，程度及范围的关系。方法 根据冠状动脉造影结果和临床表现，将256例患者分别进行分组，并比较他们的血清TnI水平。结果：（1）不稳定型心绞痛患者血清TnI水平高于稳定型心绞痛患者（P＜0．01）：（2）冠状动脉梗阻组患者血清TnI较冠状动脉狭窄患者高（P＜0．01）;(3)支病变组患者的血清TnI明显高于单支病变组患者（P＜0．01）。结论 血清TnI水平与冠状病变稳定性，程度及范围相关，对冠心病的预后判断可能具有一定价值。     

吸入一氧化氮对老年急性大面积肺血栓栓塞症患者血浆心肌肌钙蛋白的影响

伴右心室功能衰竭的肺血栓栓塞症（PET）患者右心室功能障碍和衰竭的主要原因是右心室后负荷加重使右心室壁受损。心肌肌钙蛋白（cTn）是心肌早期受损的主要指标之一，其水平和心肌受损程度与PET的临床预后呈明显负相关。     

充血性心力衰竭患者血清肌钙蛋白T、肌钙蛋白Ⅰ检测及临床分析

目的研究充血性心力衰竭患者血清肌钙蛋白T(cTnT)和肌钙蛋白Ⅰ(cTnI)水平与心功能的关系及其对预后的判断。方法检测110例不同病因、不同心功能分级的充血性心力衰竭患者的cTnT、cTnI及左室射血分数(LVEF),并与40名健康对照组的结果进行比较。结果心功能Ⅱ级组cTnT为(78.56±25.65)pg/mL,cTnI为(0.85±0.57)ng/mL,LVEF值为57.46%±4.42%;心功能Ⅲ级分别为(249.25±76.21)pg/mL、(3.75±1.83)ng/mL、44.27%±10.13%;心功能Ⅳ级组分别为(375.62±81.29)pg/mL、(8.57±2.56)ng/mL、36.75%±5.66%,与健康对照组[分别为(3.65±0.96)pg/mL、(0.02±0.01)ng/mL、65.52%±8.01%]比较,差异有统计学意义(P<0.01),且心功能越差,cTnT、cTnI浓度越高;cTnT、cTnI与LVEF值均呈负相关,r分别为-0.487、-0.360,差异有统计学意义(P<0.01)。结论检测cTnT、cTnI对于判断充血性心力衰竭患者病情严重程度及预后具有重要的临床价值,是早期评估患者风险的重要方法。     

Comparison of troponin I and N-terminal-pro B-type natriuretic peptide for risk stratification in patients with pulmonary embolism.

OBJECTIVE: We compared the usefulness of plasma N-terminal-pro B-type natriuretic peptide and troponin I levels for risk stratification of patients with pulmonary embolism. METHODS: This was a prospective study performed in an emergency department. N-terminal-B-type natriuretic peptide assay and troponin I were performed blindly at admission in patients with pulmonary embolism confirmed by imaging tests. A complicated pulmonary embolism was defined as any of the following: death, cardiopulmonary resuscitation, requirement for mechanical ventilation, use of pressors, thrombolysis, surgical embolectomy or admission in an intensive care unit. RESULTS: Sixty patients (mean age+/-standard deviation of 72+/-15 years) were included. Seventeen (28%) patients had adverse events: all were admitted in intensive care unit, one was treated with surgical embolectomy and one with thrombolysis, and three died. The median N-terminal-pro B-type natriuretic peptide level (95% confidence interval) was higher in the group of patients with complicated pulmonary embolism, 4086 pg/ml (505-8998) versus 352 pg/ml (179-662), respectively (P<0.05). The mean value of troponin I was similar in the complicated pulmonary embolism group, 0.09+/-0.17 microg/l versus 0.08+/-0.41 microg/l, respectively (P=0.93). The best threshold value of N-terminal-pro B-type natriuretic peptide was 1000 pg/ml, and the receiver operating characteristic curve demonstrated that N-terminal-pro B-type natriuretic peptide significantly predicted the complicated pulmonary embolism with an area under the receiver operative curve of 0.72 (0.58-0.83) (P<0.05), whereas troponin I did not [area under the receiver operative curve of 0.58 (0.42-0.71)]. CONCLUSION: Unlike troponin I, N-terminal-pro B-type natriuretic peptide may be an accurate marker of in-hospital complication after pulmonary embolism.     

不稳定性心绞痛患者肌钙蛋白I水平与冠状动脉病变及预后的关系

目的探讨不稳定性心绞痛（UA）患者肌钙蛋白I（cTnTI）水平与冠状动脉病变及与预后的关系。方法108例UA患者根据删是否阳性分为cTnI阳性组（41例），cTnI阴性组（67例）。在住院期间行冠脉造影（CAG）并观察其心脏事件的发生情况，对比分析两组UA患者的冠状动脉造影特点及预后。结果cTnI阳性组冠状动脉造影阳性率为92，7％。三支病变发生率51．2％，冠脉内血栓形成者为24．3％，均明显高于cTnI阴性组；cTnI阳性组cTnI水平与冠状动脉的狭窄程度有相关性，cTnI阳性组近期（30d）心脏事件发生率31．6％，亦明显高于cTnI阴性组，且两组对比差异均有显著性（P〈0，01）。结论cTnI阳性的UA患者复杂病变多，冠脉内血栓形成率高且预后较差，cTnI水平越高，冠脉狭窄越重。     

Decision for aggressive therapy in acute pulmonary embolism: implication of elevated troponin T

Background  Elevated cardiac troponin T (cTnT) has been described in the setting of acute pulmonary embolism (PE) earlier, though currently it has no implication on the therapy in this setting. The protocol established in our institution recommends the use of fibrinolytic therapy as first-line therapy in these patients only when cTnT is elevated. This analysis was performed to evaluate the safety of this regimen in regard to 30-day mortality, morbidity and complications. Methods and results  A total of 192 consecutive patients with confirmed PE, presenting at our institution during 2000–2005, were recruited. Right ventricular function was determined echocardiographically. CTnT was determined in all patients on admission. Patients without elevated cTnT were treated with anticoagulation alone, while patients with a TnT level above 0.1 ng/mL PE could be treated with thrombolysis on the discretion of the physician in charge. On day 30, cTnT elevation was associated with a higher mortality (P = 0.009). Moreover, in patients with intermediate-risk PE that were cTnT negative anticoagulation alone was safe showing a 30-day mortality of 1.8%, similar to low-risk PE (2.0%). In contrast to this patients with intermediate-risk PE with cTnT elevation showed a mortality rate of 20.8%, which was significantly higher (P < 0.001). Conclusions  In patients with intermediate-risk PE without elevated cTnT, anticoagulation alone seems to be a safe regimen. The midterm prognosis of these patients is as good as the prognosis of patients with low-risk PE. In this cohort of patients with PE, beginning with a more conservative treatment strategy per se did not lead to an unfavourable outcome.     

肌钙蛋白联合血气分析对肺栓塞诊断及危险分层的探讨

目的:通过联合检测血浆肌钙蛋白I(cTnI)和血气分析,探讨其结果对急性肺栓塞(APE)患者进行诊断及危险分层的意义。方法:根据cTnI水平和血气分析阳性结果将61例APE患者分为3组:A组(12例):cTnI<0.05μg/L且血气分析结果为阴性;B组(27例):cTnI≥0.05μg/L或血气分析结果为阳性;C组(22例):cTnI≥0.05μg/L且血气分析结果为阳性。分析cTnI和血气分析阳性结果与APE患者诊断与危险分层的关系。结果:3组中D-二聚体阳性率C组、B组较A组升高(P<0.05)。其中C组,其右心室扩大及肺动脉高压的发生率明显高于A组(P<0.01),较B组发生率增高,但差异无统计学意义。B组较A组右心室扩大及肺动脉高压的发生率明显增高(P<0.05)。病死率及心源性休克的发生率C组明显高于A组(P<0.01),B组高于A组(P<0.05)。C组大面积APE的发生率较A组、B组明显增高,差异有统计学意义(P<0.01或P<0.05)。结论:联合检测cTnI和血气分析在APE的诊断和分层中具有重要意义。     

Interaction between heparin and cardiac troponin T and troponin I from patients after coronary bypass surgery

OBJECTIVES: Heparin is thought to play a crucial role in the clinical monitoring of patients with acute coronary syndrome as well as after coronary bypass surgery in that it interferes with different commercial immunoassay test systems for cardiac troponin T (cTnT) and troponin I (cTnI). The mechanism, however, by which heparin apparently affects the cTnT and cTnI levels in plasma is not yet resolved. DESIGN AND METHODS: We analyzed the effect of heparin by simultaneously collecting serum and heparin plasma samples from 32 patients after coronary bypass surgery. The cTnT and cTnI levels were determined using the Roche/Elecsys, the Dade-Behring/Opus and the Bayer/ACS:Centaur immunoassay systems in the absence or in the presence of either heparinase or protamine. Association between the cardiac troponins and the anticoagulant has been demonstrated by affinity chromatography using heparin as the ligand. RESULTS: The data obtained indicate that heparin produces an apparent decrease in cTnT as well as of cTnI levels, analyzed either by the Elecsys, the Opus or the ACS:Centaur immunoassay systems. Individual patients show a wide variation in the discrepancies between serum and heparin plasma troponin especially in the cTnT immunoassay. Pretreatment of the heparin plasma samples either with heparinase or protamine cannot completely reverse the heparin-induced decrease in cTnT and cTnI levels and therefore addition of these reagents to the commercial test systems could not significantly improve the performance of the assay. When serum is supplemented with increasing concentrations of heparin, and cardiac troponin levels were reanalysed, significantly lower recoveries for the cTnT than for the cTnI immunoassays were detectable. Affinity chromatography with heparin Sepharose demonstrates that cTnT and cTnI interact differentially with the negatively charged ligand. Whereas cTnI shows minor affinity to the immobilized heparin and is eluted at near physiological conditions, cTnT is bound and can be quantitatively recovered only by solutions of high ionic strength. CONCLUSIONS: We conclude, therefore, that the apparent decrease in cTnT values by addition of heparin is a result of direct molecular interaction between the negatively charged glycosaminoglycan and clusters of basic residues within the sequence of the cardiac protein. In contrast, the effect of heparin on the cTnI immunoassay systems, is primarily indirect, most possibly induced by changes within the sample matrix itself.     

心肌肌钙蛋白I对小儿心肌炎的诊断价值及与肌酸激酶同功酶MB的对比研究

目的评估血清心肌肌钙蛋白 I( c Tn I)对小儿心肌炎的诊断价值 ,并与肌酸激酶同功酶 MB( CK-MB)进行对比研究。方法全自动生化分析仪对 c Tn I及 CK-MB进行定量检测。结果 1心肌炎组 c Tn I及 CK-MB均明显高于正常对照组 ( P<0 .0 0 1)。 c Tn I升高 2 2例 ,占 73% ,CK-MB升高 15例 ,占 5 0 % ,c Tn I与 CK-MB呈正相关。 2治疗 2周后 c Tn I与对照组比较有显著性差异 ( P<0 .0 0 1) ,CK-MB与对照组无显著性差异 ( P>0 .0 5 )。 3心肌炎组 13例 ST-T改变患儿测 c Tn I升高 12例 ( 92 % ) ,CK-MB升高 6例 ( 4 6 % )。结论 c Tn I及 CK-MB对小儿肌炎的诊断均较敏感。 c Tn I诊断时间窗宽于 CK-MB,特异性高于 CK-MB     

Differential associations of cardiac troponin T and cardiac troponin I with coronary artery pathology and dynamics in response to short-duration exercise

BackgroundWe aimed to assess the associations between cardiac troponin (cTn) T and I concentrations, physical exercise and the presence and severity of angiographic coronary artery disease (CAD) in patients evaluated for suspected chronic coronary syndrome (CCS).Methods and resultsAll patients performed an exercise stress test on a bicycle ergometer and underwent invasive coronary angiography with weighted anatomical evaluation using the Gensini score. Blood samples were collected before and after exercise and analysed with high-sensitivity (hs) cTnT and cTnI assays.Of 297 patients (median age 62 (Quartile [Q]1–3 56–69) years, 35% female), 46% were categorized as “severe CAD” (Gensini score ≥ 20).Resting hs-cTnT and hs-cTnI concentrations were detectable in 88% and 100% of patients, with medians of 6 (Q1-3 4–9) ng/L and 1.5 (0.9–2.4) ng/L, respectively.In adjusted normalized linear regression analyses, higher resting concentrations were associated with increasing Gensini score (hs-cTnT: B 0.19, 95% Confidence Interval [CI] [0.09–0.41], p < 0.001; hs-cTnI: B 0.18, [0.06–0.30], p = 0.002).The area under the receiver operating characteristics curve for predicting severe CAD was 0.72 (95% CI [0.66–0.78]) and 0.68 (0.62–0.74) for resting hs-cTnT and hs-cTnI, p = 0.11 for difference.The median (Q1-3) relative increase in hs-cTnT and hs-cTnI concentrations were 5 (0–12) % and 13 (3–27) %, respectively, with no significant associations with CAD severity.ConclusionsIn patients with suspected CCS, higher hs-cTn concentrations at rest were associated with increasing angiographic severity of CAD, without any significant differences between the troponin isotypes. Post-exercise hs-cTn concentrations did not have discriminatory power for CAD.     

心肌肌钙蛋白Ⅰ对小儿心肌炎的诊断价值及与肌酸激酶同功酶MB的对比研究

目的评估血清心肌肌钙蛋白I(cTnI)对小儿心肌炎的诊断价值,并与肌酸激酶同功酶MB(CK-MB)进行对比研究.方法全自动生化分析仪对cTnI及CK-MB进行定量检测.结果①心肌炎组cTnI及CK-MB均明显高于正常对照组(P＜0.001).cTnI升高22例,占73%,CK-MB升高15例,占50%,cTnI与CK-MB呈正相关.②治疗2周后cTnI与对照组比较有显著性差异(P＜0.001),CK-MB与对照组无显著性差异(P＞0.05).③心肌炎组13例ST-T改变患儿测cTnI升高12例(92%),CK-MB升高6例(46%).结论 cTnI及CK-MB对小儿肌炎的诊断均较敏感.cTnI诊断时间窗宽于CK-MB,特异性高于CK-MB.     

血栓性微血管病患者肾动脉阻力指数与肾功能的相关性研究

目的 探讨血栓性微血管病(TMA)患者肾动脉阻力指数(RRI)与肾功能的相关性,为患者急性肾损伤(AKI)可预见性的诊断、处理提供依据.方法 选取北京协和医院急诊科2014年8月至2015年3月收治的46例TMA患者为研究对象,于入院当日测量患者右肾小叶间动脉的RRI并记录血清肌酐(SCR)及肾小球滤过率(GFR)数值,按照2012年“改善全球肾脏病预后组织”(KDIGO)指南中A KI的诊断标准将患者分为AKI组和非AKI组,比较组间差异,分析RRI对AKI的诊断意义及RRI与SCR、GFR的相关性.所有患者在肾损伤最重时再次测量RRI(RRI*),记录此时的SCR(SCRmax)与GFR(GFRmin),计算△RRI(RRI*-RRI)、△SCR(SCRmax-SCR)、△GFR(GFR-GFRmin),并将治疗期间达到A KI诊断标准的36患者进一步分为KDIGO-1期、KDIGO-2期及KDIGO-3期3个组,比较RRI*组间差异,分析△RRI与△SCR、△GFR的相关性.结果 入院时以RRI ＞0.7来诊断AKI,敏感度为92.3％,特异度为80.1％.患者入院及肾损伤最严重时的RRI与同时期的SCR显著正相关(r1=0.709,P＜0.01;r2=0.675,P＜0.01),与GFR显著负相关(r1=-0.728,P＜0.01;r2=-0.709,P＜0.01).3组AKI患者RRI*差异有统计学意义(F=37.979,P=0.001),但△RRI比较差异无统计学意义(F=0.634,P=0.537);Spearman相关分析结果表明3组A KI患者的△RRI与ASCR、△GFR之间无相关性(均P＞0.05).结论 监测TMA患者的RRI有助于A KI的诊断并能评价肾损伤程度,但不能准确反映肾损伤的变化趋势.     

肌钙蛋白I和T测定对急性心肌梗塞的诊断意义

目的探讨肌钙蛋白I（cTnI）和肌钙蛋白T（cTnT）测定对急性心肌梗塞（AMI）的诊断价值。方法对52例AMI患者采用免疫层析法进行检测cTnI和cTnT,以对照区和检测区均有显色带者为阳性,并作灵敏度和特异性的比较。结果以胸痛0～3h、4～6h两个时段观察其灵敏度,cTnI为56.7%和96.1%;cT-nT为50.0%和92.3%。特异性cTnI为100%和96.2%;cTnT为100%和91.6%。cTnI灵敏度高于cTnT,特异性cTnI与cTnT之间无显著性差异。结论对AMI急性胸痛患者可同时进行cTnI和cTnT检测,有利于AMI的诊断和治疗。     

Circulating cardiac troponin I in trauma patients without cardiac contusion

Objectives: To describe the evolution and the diagnostic value of cardiac troponin I (cTnI) and to relate its concentrations with the indicators of injury in trauma patients. Design: Prospective, observational study of 17 young, previously healthy, mechanically-ventilated patients during the early post-traumatic period in the Surgical ICU of a University Hospital. Methods: Serial measurements of serum cTnI, total creatine kinase activity (CKtot) and its isoenzyme MB (CK-MB) (on admission, 12 h later, then daily for 7 days), clinical data and repeated electrocardiographic (ECG) and transesophageal echocardiographic (TEE) recordings. Results: Rhabdomyolysis was observed in all the patients with a significant relationship between CK-MB and CKtot. Despite the fact that no patient demonstrated ECG or TEE signs of myocardial contusion, elevated serum levels of cTnI were observed in six patients (35 %) without obvious dilutional interference. As compared with the others, these patients exhibited a more frequent arterial hypotension (83 % vs 18 %, p = 0.035), required greater volume expansion on day 1 (22,000 vs 8,500 ml, p = 0.027) and usually demonstrated early (83 % vs 9 %, p = 0.005) and late (66 % vs 9 %, p = 0.028) multiple organ dysfunction syndrome. Conclusions: Taking into account the high reported sensitivity and specificity of cTnI dosage, the present results suggest cTnI can play a role in the evaluation of indirect myocardial injury following traumatic shock. Received: 20 November 1997 Accepted: 3 March 1998