Human heart-type fatty acid-binding protein as an early diagnostic and prognostic marker in acute coronary syndrome

Although heart-type fatty acid-binding protein (H-FABP) can be a marker of sarcolemmal injury due to acute myocardial ischemia, the diagnostic or prognostic value is not established in patients with acute chest pain. This multicenter prospective study aimed to determine the diagnostic and prognostic values of H-FABP in 133 patients presenting to an emergency room with suspected acute coronary syndrome (ACS) by comparing with those of conventional biomarkers. H-FABP and myoglobin had greater positive results than did creatine kinase-MB or troponin T. Receiver operating characteristics analysis revealed that H-FABP was the most reliable for detection of ACS and that H-FABP had the greatest sensitivities for identification of patients requiring emergency hospitalization, coronary angiography, and interventional therapy within 7 days among the biomarkers. Thus, H-FABP can be an early diagnostic and prognostic biochemical marker, particularly within the first 6 h from the onset of chest symptoms, in patients with chest pain at an emergency department.     

Diagnostic and prognostic value of heart-type fatty acid-binding protein (H-FABP), an early biochemical marker of myocardial injury

Heart-type fatty acid-binding protein (H-FABP) is a 132 amino acids soluble protein, with general characteristics resembling myoglobin. Because of its low molecular weight (15 kd) and cytoplasmic location, it constitutes a biologic marker readily released into the circulation after myocardial injury. Despite the development of various immunoassays to measure H-FABP, few are currently easy to perform, quantitative and applicable in emergency. Most studies have shown the diagnostic sensitivity of H-FABP (i.e. its ability to detect the presence of a myocardial infarction) to be high, above that of myoglobin in patients presenting within 3 to 6 h of after the onset of chest pain. This superiority is attributable to an earlier and more rapid rise in H-FABP than in myoglobin. After thrombolysis, the serum concentrations of H-FABP peak at approximately 4 h after the onset of chest pain, and return to normal values within 24 h. Because of this rapid return of its blood concentration to baseline, H-FABP can contribute to an early biologic diagnosis of post-thrombolysis reperfusion and re-infarction. In absence of renal insufficiency, H-FABP also provides a reliable estimate of infarct size associated with ST segment elevation. When myocardial injury occurs after cardiac surgery, the second peak in H-FABP concentration precedes that of myoglobin, CK-MB or troponins. In addition, H-FABP peaks earlier and is more sensitive than troponins in the detection of subtle myocardial injury in patients presenting with acute coronary syndrome without ST segment elevation, and in patients with severe heart failure, thus offering early prognostic information. Limitations of H-FABP include a limited cardio-specificity, a narrow diagnostic window (20 to 30 h), and a nearly exclusive renal elimination.     

The use of human heart-type fatty acid-binding protein as an early diagnostic biochemical marker of myocardial necrosis in patients with acute coronary syndrome, and its comparison with troponin-T and creatine kinase–myocardial band

Heart-type fatty acid-binding protein (H-FABP), a new biochemical marker of sarcolemmal injury due to acute myocardial ischemia, can be used as a tool in early diagnosis and management of patients at high risk. The aim of this study was to determine the early diagnostic value of H-FABP in acute coronary syndrome (within 6–24 h of chest pain) and to compare it with troponin-T (TnT) and creatine kinase–myocardial band (CK-MB) for accuracy. The study consisted of 40 consecutive patients with chest pain admitted to the coronary care unit with the diagnosis of suspected acute coronary syndrome. The patient population consisted of two groups according to the time of admission; the first group (26 patients) included patients admitted within 6 h of chest pain, and the second group (14 patients) included patients admitted within 6–24 h of chest pain. The blood samples for H-FABP, TnT, and CK-MB were obtained at admittance, at the 6th, and at the 24th hours for the first group, and at admittance and at the 24th hours for the second. Statistical analysis was performed among the 26 patients for the first 6 h values, and among all 40 patients for the values obtained within 6–24 h and at the 24th hour. The patients were then divided into groups according to the changes in the electrocardiogram (ECG) and cardiac enzymes as unstable angina pectoris, non-ST elevation myocardial infarction (MI), and ST-elevation MI. Coronary angiography was performed in 38 (95%) patients. Sensitivity of TnT, CK-MB, and H-FABP in the first group (within 6 h of chest pain) were 38%, 76%, and 95% respectively. The sensitivity of H-FABP was significantly higher than TnT (P = 0.014). Sensitivity of TnT, CK-MB, and H-FABP tests in the second time period (within 6–24 h of chest pain) were 100%, 90%, and 91% respectively. In this time period, the sensitivity of TnT was higher than H-FABP, but it was statistically insignificant. At the 24th hour, sensitivity of TnT was 100%, CK-MB 90%, and H-FABP 27.3%, and TnT and CK-MB were more sensitive than H-FABP for the whole group (P = 0.002). In the first group (within 6 h of chest pain) H-FABP positivity was slightly but insignificantly higher in patients with two- and three-vessel disease compared with those with one-vessel disease (60.7% and 33.3%, P = 0.19) and in the same group, patients who underwent primary coronary intervention had a significantly higher H-FABP positivity than others (80%, 32%, P = 0.02). Within 6–24 h of chest pain, H-FABP positivity was 80% in patients with one-vessel disease and 71.4% in patients with two- and three-vessel disease (P = 0.69). Within 6–24 h, positivity of H-FABP reached a peak value of 100% in patients who underwent primary coronary intervention, while H-FABP was positive in 60% of the others (P < 0.001). We conclude that within the 6 h of acute coronary syndrome, H-FABP seems to be a more sensitive biochemical marker than TnT in the early detection of ischemic myocardial necrosis. But after the first 6 h of the onset of chest pain the sensitivity of H-FABP decreases, and this marker should not be used alone in patients admitted 24 h after the onset of chest pain.     

Circulating levels of myocardial proteins predict future deterioration of congestive heart failure

BACKGROUND: This study was designed to test whether circulating levels of myocardium-specific proteins serve as useful markers for the prognosis of patients with congestive heart failure. METHODS AND RESULTS: Seventy-eight patients with congestive heart failure from dilated cardiomyopathy but in a stable condition were enrolled, and their blood was sampled for measurements of myosin light chain-I (MLC-I), troponin T (TnT), heart fatty-acid-binding protein (H-FABP), and creatine kinase isoenzyme MB (CK-MB). The patients were then followed up for 951 +/- 68 days, with the endpoint being acute deterioration. A univariate analysis revealed that MLC-I, TnT, H-FABP, and CK-MB were significant predictors for acute deterioration of heart failure. Application of the Kaplan-Meier method using cutoff values determined by analysis of receiver operating characteristics curves demonstrated that the incidence of acute deterioration was significantly higher in patients with higher values of MLC-I (61.9%), TnT (52.4%), H-FABP (50.0%), or CK-MB (38.6%) than in those with lower values of these markers (15.8%, 20.4%, 13.6%, and 16.1%, respectively). CONCLUSIONS: Increased circulating levels of the specific myocardial proteins are related to a higher probability of future acute deterioration of congestive heart failure in patients in a stable condition associated with dilated cardiomyopathy.     

Comparison of troponin T versus creatine kinase-MB in suspected acute coronary syndromes

Limitations of creatine kinase-MB (CK-MB) have led to alternative biochemical markers, including troponin T (TnT), to detect myocardial necrosis. Limited data are available regarding the predictive value of this new marker in patients with chest pain of uncertain etiology. Therefore, we prospectively compared CK-MB and TnT in a broad population with suspected acute coronary syndromes, including those admitted to a short-stay chest pain unit. CK-MB, quantitative TnT levels, and a rapid bedside assay were performed at 0, 4, 8, and 16 hours. Adverse events, including infarction, recurrent ischemia, coronary surgery, need for catheterization and/or intervention, stroke, congestive heart failure, or death, were identified by chart review and by follow-up phone call at 6 months. Of 707 patients, 104 were excluded for creatinine >2 mg/dl or incomplete data, leaving a total cohort of 603 patients. Coronary Care Unit admissions were 18%, intermediate care admissions were 14%, telemetry admissions is 21%, and admissions to 24-hour short-stay area were 47%. TnT (at 0.1 ng/ml) and CK-MB were positive in a similar proportion of patients (20.4% and 19.7%, respectively); however, the patients identified by TnT and CK-MB were not identical. In-hospital adverse events occurred in 37.1% with no differences in positive predictive value for the markers (p = NS). If CK-MB and TnT were negative, the early adverse event rate was 27%. No cardiac marker was positive by 16 hours in 54.9% of patients with an adverse event. Six-month follow-up was obtained in 576 of the 603 patients (95.5%). One hundred fifty-five late adverse events occurred in 134 patients (23.3%) at an average of 3.3+/-2.5 months after discharge. If both markers were negative, the late event rate was 20.2% and did not increase in patients with positive CK-MB or TnT >0.2 ng/ml. However, the late event rate was substantially higher (52.9%) in those with intermediate TnT levels of 0.1 to 0.2 ng/ml (p = 0.002). Thus, TnT is a suitable alternative to CK-MB in patients with suspected acute coronary syndromes. The rapid bedside assay is comparable to quantitative TnT and may enable early diagnosis and triage. A negative cardiac marker value (TnT or CK-MB) does not necessarily confer a low risk of complication in patients presenting with acute chest pain to an emergency department.     

Heart-type fatty acid-binding protein (H-FABP) as an early diagnostic biomarker in patients with acute chest pain

Background

Heart-type fatty acid-binding protein (H-FABP) is an emerging biomarker, which was found to be sensitive for the early diagnosis of acute myocardial infarction (AMI). We prospectively investigated the usefulness of H-FABP determination for the evaluation of acute chest pain in patients arriving at the emergency department.

Methods

Fifty-four patients presenting with acute ischemic chest pain were evaluated. H-FABP was estimated at admission using latex-enhanced immunoturbidimetric assay. Serial cardiac troponin I (cTnI), creatinine kinase-MB (CK-MB) determination, ischemia workup with stress testing, and/or coronary angiogram (CAG) were performed according to standard protocols.

Results

The sensitivity and specificity of H-FABP was 89.7% and 68%, for cTnI it was 62.1% and 100%, and for CK-MB it was 44.8% and 92%, respectively for diagnosis of AMI. The sensitivity of H-FABP was found to be far superior to initial cTnI and CK-MB, for those seen within 6 h (100% vs. 46.1%, 33% respectively). On further evaluation of patients with positive H-FABP and negative cTnI, 71.4% of the patients had significant lesion on CAG, indicating ischemic cause of H-FABP elevation. Six patients with normal cTnI and CK-MB with high H-FABP had ST elevation on subsequent ECGs and were taken for primary angioplasty.

Conclusion

H-FABP is a highly sensitive biomarker for the early diagnosis of AMI. H-FABP as early marker and cTnI as late marker would be the ideal combination to cover the complete diagnostic window for AMI. Detection of myocardial injury by H-FABP may also be applied in patients with unstable angina. H-FABP can also be used as a marker for early detection of STEMI before the ECG changes become apparent.     

心肌型脂肪酸结合蛋白检测在急性心肌梗死早期诊断中的应用

目的:探讨心肌型脂肪酸结合蛋白(H-FABP)在急性心肌梗死(AMI)早期诊断中的应用价值.方法:选择110例因急性胸痛住院的患者,按胸痛发作时间到就诊时间先后分为＜3 h、3～6 h和＞6 h三组,检测各组H-FABP、肌酸激酶同工酶(CK-MB)、肌钙蛋白I(cTnI)水平变化,比较3种心肌标志物诊断早期AMI的敏感性、特异性、阳性预测值、阴性预测值,同时比较胸痛发作≤6h时不同心肌标志物联合诊断AMI的敏感性、特异性、阳性预测值、阴性预测值.结果:入选病例最终确诊为AMI 62例,非AMI 48例(其中不稳定型心绞痛20例,稳定型心绞痛18例,非心源性胸痛10例).＜3 h组H-FABP、CK-MB、cTnI水平诊断AMI的敏感性分别为87.5％、9.1％、45.8％;特异性分别为83.3％、91.6％、91.6％;3～6 h组H-FABP、CK-MB、cTnI水平诊断AMI的敏感性分别为98.1％、54.5％、63.6％;特异性分别为94.4％、88.9％、93.7％;＞6 h组H-FABP、CK-MB、cTnI水平诊断AMI的敏感性分别为81.3％、93.7％、75.0％;特异性分别为83.3％、94.4％、100％;3种检测指标的特异性、阴性预测值、阳性预测值差异无统计学意义(P＞0.05);胸痛发作≤6h时H-FABP与cTnI联合检测诊断AMI的敏感性为93.5％、特异性为85.4％,cTnI与CK-MB联合检测诊断AMI的敏感性为74.1％、特异性为87.5％.结论:H-FABP水平检测对于早期诊断AMI有较高的敏感性,优于传统指标CK-MB、cTnI,但特异性、阳性预测值、阴性预测值与CK-MB、cTnI相当.胸痛发作≤6h时H-FABP与cTnI联合检测可进一步提高AMI早期诊断的敏感度,优于传统的cTnI与CK-MB联合检测.     

Peak cardiac troponin-T level, scintigraphic myocardial infarct size and one-year prognosis in patients undergoing primary percutaneous coronary intervention for acute myocardial infarction

Current guidelines recommend troponin T (TnT) as the biomarker of choice in the diagnosis of myocardial infarction. In patients with ST-elevation myocardial infarction (STEMI) however, its role in providing a measurement of infarct size and its association with survival is less well established. We sought to assess the correlation of TnT and creatine kinase-MB (CK-MB) with scintigraphically determined infarct size and to assess the predictive value of all 3 parameters on 12-month mortality. Patients presenting with STEMI managed with primary percutaneous intervention underwent serial TnT and CK-MB measurements at admission and for ≥72 hours after presentation. Before hospital discharge patients underwent assessment of infarct size by technetium-99m sestamibi single-photon emission computed tomographic (SPECT) scan. Clinical follow-up was performed up to 1 year. Data were available for 1,237 patients. Mean age was 62.9 ± 12.9 years. Infarct location was anterior in 509 patients (41%); 75 (6.1%) had cardiogenic shock. Median admission and peak TnT were 0.74 μg/L (0.10 to 2.70) and 3.70 μg/L (1.69 to 6.99), respectively. Corresponding values for CK-MB were 44.1 U/L (21.0 to 108.8) and 160.0 U/L (69.0 to 301.0), respectively. Median infarct size on SPECT scan was 12.0% (3.0 to 25.0) of the left ventricle. Peak TnT and CK-MB demonstrated similar moderate correlation with final infarct size (r = 0.45, p <0.001, and r = 0.41, p <0.001 respectively). This correlation was not affected by Thrombolysis In Myocardial Infarction flow grade after intervention. At 1 year, 47 patients (3.8%) had died. Final infarct size at SPECT scanning better predicted mortality than peak TnT or CK-MB. In conclusion, this study is the largest investigation on the value of cardiac troponin for assessment of infarct size in acute STEMI. Compared to peak CK-MB, peak TnT shows similar correlation with scintigraphic infarct size, although scintigraphic infarct size remains a better correlate of 1-year mortality than either biomarker.     

The value of human heart-type fatty acid binding protein in diagnosis of patients with acute chest pain

BackgroundThe aim was to determine the efficacy of heart-type fatty acid-binding protein (H-FABP) compared with routinely myoglobin (MYO), creatine kinase-MB (CK-MB) and cardiac troponin-I (cTn-I) in the early diagnosis of acute myocardial infarction (AMI) in patients presenting with acute chest pain.Methods and resultsThe patients were classified as AMI (n = 22), unstable angina (UA, n = 20) and non-cardiac chest pain (NCCP, n = 15) within 3 h and 6 h of acute chest pain according to the American College/European Society of Cardiology; and normal healthy subjects (controls, n = 10). Blood H-FABP levels were measured by ELISA and compared with cTn-I, CK-MB and MYO in all subjects. The diagnostic sensitivity, specificity and receiver operating characteristic (ROC) curve were evaluated. Serum H-FABP, MYO, CK-MB and cTn-I were significantly higher in AMI more than the UA, NCCP (non-AMI) and control groups within 6 h. However, Serum H-FABP, MYO and CK-MB were significantly elevated within 0–3 h and extend more within 3–6 h in AMI versus non-AMI. The cutoff value of H-FABP in AMI was 21.85 ng/ml within 3 h, and has diagnostic sensitivity (81.8%) equal to that of CK-MB and cTn-I but superior to that of MYO (72.7%). However, H-FABP has higher specificity (88.2%) equal to that of MYO but superior to that of CK-MB and cTn-I. This trend extends to within 6 h as well. Moreover, ROC curve areas for H-FABP were significantly higher (p < 0.05) than other biomarkers <6 h after the onset of chest pain.ConclusionH-FABP can be used as a sensitive biomarker for myocardial injury in early stage.     

Ninety-minute accelerated critical pathway for chest pain evaluation

Rapid, efficient, and accurate evaluation of chest pain patients in the emergency department optimizes patient care from public health, economic, and liability perspectives. To evaluate the performance of an accelerated critical pathway for patients with suspected coronary ischemia that utilizes clinical history, electrocardiographic findings, and triple cardiac marker testing (cardiac troponin I [cTnI], myoglobin, and creatine kinase-MB [CK-MB]), we performed an observational study of a chest pain critical pathway in the setting of a large Emergency Department at the Veterans Affairs Medical Center in 1,285 consecutive patients with signs and symptoms of cardiac ischemia. The accelerated critical pathway for chest pain evaluation was analyzed for: (1) accuracy in triaging of patients within 90 minutes of presentation, (2) sensitivity, specificity, positive predictive value, and negative predictive value of cTnI, myoglobin, and CK-MB in diagnosing acute myocardial infarction (MI) within 90 minutes, and (3) impact on Coronary Care Unit (CCU) admissions. All MIs were diagnosed within 90 minutes of presentation (sensitivity 100%, specificity 94%, positive predictive value 47%, negative predictive value 100%). CCU admissions decreased by 40%. Ninety percent of patients with negative cardiac markers and a negative electrocardiogram at 90 minutes were discharged home with 1 patient returning with an MI (0.2%) within the next 30 days. Thus, a simple, inexpensive, yet aggressive critical pathway that utilizes high-risk features from clinical history, electrocardiographic changes, and rapid point-of-care testing of 3 cardiac markers allows for accurate triaging of chest pain patients within 90 minutes of presenting to the emergency department.     

Plasma and urinary levels of heart fatty acid-binding protein in patients undergoing cardiac surgery

To evaluate the clinical significance of the plasma and urinary levels of heart fatty acid-binding protein (H-FABP) in patients undergoing cardiac surgery, a prospective study was conducted. Ten patients undergoing coronary artery bypass grafting were enrolled. Blood samples for determination of plasma H-FABP (pH-FABP), the MB isoenzyme of creatine kinase (CK-MB) and troponin-T (TnT), and urine samples for determination of urinary H-FABP (uH-FABP) were collected serially. None of the patients had perioperative myocardial infarction. The time to reach the peak level after aortic declamping was significantly (p<0.05) shorter for pH-FABP (1.4+/-0.5 h) than for CK-MB (2.5+/-0.5 h), TnT (6.6+/-1.3 h) or uH-FABP (3.0+/-0.6 h). Peak levels of pH-FABP correlated with those of CK-MB (r = 0.51, p = 0.04), TnT (r = 0.60, p = 0.03) and uH-FABP (r = 0.61, p = 0.03), and peak levels of uH-FABP correlated with CK-MB (r = 0.57, p = 0.04). Postoperative uH-FABP levels correlated inversely with the left ventricular stroke work index (r = -0.63, p = 0.04). This study demonstrated that H-FABP appears rapidly in plasma after reperfusion and reaches its peak earlier than other available biochemical markers; it appears also in urine and the levels correlated with cardiac function. Plasma and urinary H-FABP may be an early and sensitive biochemical marker for the diagnosis of myocardial injury in patients undergoing cardiac surgery.     

心肌脂肪酸结合蛋白对早期急性心肌梗死的诊断

目的研究血浆心肌脂肪酸结合蛋白(HFABP)在早期急性心肌梗死(AMI)诊断中的价值。方法选择93例发病6h内的胸痛患者,其中AMI组32例,非AMI组61例[含不稳定型心绞痛(UAP)24例,稳定型心绞痛(SAP)者22例,非心源性胸痛者15例];正常对照组选择69例正常人。采用双抗体夹心酶联免疫一步法检测正常人和患者发病0～3h或3～6h血浆的HFABP含量,并与心肌肌钙蛋白I(cTnI)、肌酸激酶同工酶(CKMB)和肌红蛋白(MYO)的检测结果进行比较,分析4种生化标志物诊断发病3h内和6h内AMI的敏感性、特异性和准确性。结果在0～3h、0～6h时间段,HFABP诊断AMI的敏感性(64.29%、84.38%)显著高于cTnI(28.57%、53.13%)和CKMB(21.43%、56.25%),与MYO(71.43%、78.13%)比较差异无统计学意义;在诊断特异性上,4种生化标志物差异无统计学意义;在诊断准确性上,HFABP的ROC曲线下面积(0.979、0.958)显著高于cTnI(0.800、0.878)、CKMB(0.575、0.782)和MYO(0.796、0.882)。结论HFABP对于诊断早期AMI具有较高的敏感性和良好的特异性,其诊断准确性优于cTnI、CKMB、MYO。     

Biochemical markers of ischaemia for the early identification of acute myocardial infarction without St segment elevation

Blood was collected on admission and after 1-2 h in 130 consecutive patients admitted with typical chest pain in order to assess the capacity of myoglobin, fatty-acid-binding protein (FABP), CK-MB mass, and troponin I (TnI) in the early identification of acute myocardial infarction (AMI) without ST elevation. Using the maximum value within 6 h of onset of symptoms, AMI was detected with a 90-95% sensitivity and a 81-94% specificity by FABP at a cut-off level 8-12 midrog/l, or 81-86% and 89-93%, respectively, by myoglobin at a cut-off level 70-90 microg/l. CK-MB mass and TnI had low sensitivity, albeit very high specificity. As almost all AMI patients were identified within 6 h, serial measurements of FABP or myoglobin ruled out AMI with a very high degree of certainty. Due to the low prevalence of AMI (16%), the positive predictive values were modest (47-73%), yet increasing the probability of AMI by a factor 3-4. Myoglobin and FABP are very useful markers in the early triage of chest pain patients.     

The prognostic significance of serial myoglobin,troponin I,and creatine kinase-MB measurements in patients evaluated in the emergency department for acute coronary syndrome

STUDY OBJECTIVE: We sought to determine the value of serial measurements of myoglobin, cardiac troponin I (cTnI), and creatine kinase-MB (CK-MB) to predict 30-day adverse events in patients evaluated in the emergency department (ED) for possible acute coronary syndrome. METHODS: Serum myoglobin, cTnI, and CK-MB levels were measured at presentation, 90 minutes, 3 hours, and 9 hours in patients evaluated in the ED for possible acute coronary syndrome. In 764 consecutive patients, the ability of each individual marker and combination of markers to predict a 30-day adverse event (death or myocardial infarction) over time was calculated. RESULTS: There were 109 (14%) patients with an adverse event at 30 days (84 myocardial infarctions and 43 deaths). The sensitivities of initial measurements of myoglobin, cTnI, and CK-MB for identifying adverse events were 60%, 47%, and 52%, respectively. The combined sensitivity of myoglobin and cTnI measurements during a 9-hour period was 94%; specificity was 50%. Measurement of CK-MB did not improve sensitivity. CONCLUSION: The measurement of both myoglobin and cTnI during a 9-hour period was the most predictive of subsequent adverse events in patients evaluated in the ED for possible acute coronary syndrome.     

Heart type fatty acid binding protein is more sensitive than troponin I and creatine kinase myocardial band at early stage in determining myocardial injury caused by percutaneous coronary intervention

Measurement of circulating cardiac biomarkers has enabled early diagnosis and risk assessment of acute coronary syndrome. Heart type fatty acid binding protein (H-FABP) is a relatively novel marker for the diagnosis of myocardial injury. The purpose of the present study was to compare H-FABP with Troponin I (cTnI) and creatine kinase myocardial band (CK-MB) in determining myocardial injury in patients with early stage of percutaneous coronary intervention (PCI). Blood was withdrawn one hour before and 3 hours after PCI from 40 patients to measure H-FABP, cTnI and CKMB. H-FABP was measured qualitatively. CK-MB and cTnI were measured by a sandwich enzyme-linked immunosorbent assay. Before PCI, H-FABP was found to be negative, while cTnI and CK-MB were found to be in normal ranges. Statistical analysis of measurements 3 hours after PCI revealed that H-FABP was significantly positive in 15 (37%) patients, while cTnI was elevated in 11 (27%) patients and CKMB was elevated in 8 (20%) patients. H-FABP is statistically more sensitive than cTnI and CK-MB at detecting myocardial injury after PCI.H-FABP can be used in early stages to detect myocardial injury caused by PCI. H-FABP is more sensitive than cTnI and CK-MB in determining myocardial injury due to PCI within 3 hours. H-FABP may help us stratify a patient's risk in early stages after PCI.     

A randomized trial of the effects of early cardiac serum marker availability on reperfusion therapy in patients with acute myocardial infarction: the serial markers, acute myocardial infarction and rapid treatment trial (SMARTT)

OBJECTIVES: The purpose of this study was to assess whether the immediate availability of serum markers would increase the appropriate use of thrombolytic therapy. BACKGROUND: Serum markers such as myoglobin and creatine kinase, MB fraction (CK-MB) are effective in detecting acute myocardial infarction (AMI) in the emergency setting. Appropriate candidates for thrombolytic therapy are not always identified in the emergency department (ED), as 20% to 30% of eligible patients go untreated, representing 10% to 15% of all patients with AMI. Patients presenting with chest pain consistent with acute coronary syndrome were evaluated in the EDs of 12 hospitals throughout North America. METHODS: In this randomized, controlled clinical trial, physicians received either the immediate myoglobin/CK-MB results at 0 and 1 h after enrollment (stat) or conventional reporting of myoglobin/CK-MB 3 h or more after hospital admission (control). The primary end point was the comparison of the proportion of patients within the stat group versus control group who received appropriate thrombolytic therapy. Secondary end points included the emergent use of any reperfusion treatment in both groups, initial hospital disposition of patients (coronary care unit, monitor or nonmonitor beds) and the proportion of patients appropriately discharged from the ED. RESULTS: Of 6,352 patients enrolled, 814 (12.8%) were diagnosed as having AMI. For patients having AMI, there were no statistically significant differences in the proportion of patients treated with thrombolytic therapy between the stat and control groups (15.1% vs. 17.1%, p = 0.45). When only patients with ST segment elevation on their initial electrocardiogram were compared, there were still no significant differences between the groups. Also, there was no difference in the hospital placement of patients in critical care and non- critical care beds. The availability of early markers was associated with more hospital admissions as compared to the control group, as the number of patients discharged from the ED was decreased in the stat versus control groups (28.4% vs. 31.5%, p = 0.023). CONCLUSIONS: The availability of 0- and 1-h myoglobin and CK-MB results after ED evaluation had no effect on the use of thrombolytic therapy for patients presenting with AMI, and it slightly increased the number of patients admitted to the hospital who had no evidence of acute myocardial necrosis.     

Prognostic value of troponin T, myoglobin, and CK-MB mass in patients presenting with chest pain without acute myocardial infarction.

OBJECTIVE: To assess the prognostic value of minor myocardial damage in patients presenting with chest pain without myocardial infarction. DESIGN: The relative risk of suffering a cardiac event in the next six months was assessed in patients with minor myocardial damage assessed by the cardiac markers CK-MB, myoglobin, and troponin T. SETTING: Emergency department of a large university hospital. PATIENTS: In 128 consecutive patients with chest pain, acute myocardial infarction (by WHO criteria) was ruled out; of these, 39 had a rise and fall of one or more markers, indicating minor myocardial damage. The presence of a documented history of coronary artery disease was assessed on admission. RESULTS: 24 patients had a subsequent event (cardiac death, acute myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting) in the next six months. An abnormal troponin T predicted a subsequent event while abnormal CK-MB or myoglobin did not. The relative risk for troponin T was 2.8 (95% confidence interval: 1.0 to 7.9), for myoglobin 1.0 (0.3 to 3.2), and for CK-MB 0.9 (0.2 to 3.4). A documented history of coronary artery disease predicted subsequent events with a relative risk of 3.9 (1.3 to 11.3). CONCLUSIONS: Troponin T was the only marker that predicted future events, but a documented history of coronary artery disease was the best predictor in patients in whom an acute myocardial infarction had been ruled out.     

A double-blind, multicentered study comparing the accuracy of diagnostic markers to predict short- and long-term clinical events and their utility in patients presenting with chest pain.

BACKGROUND: Millions of patients present annually with chest pain, but only 10% have myocardial infarction (MI). We recently reported comparative sensitivity and specificity of available markers in the diagnosis of MI; however, optimum interpretation of marker results requires prognostic follow-up data. HYPOTHESIS: The study was undertaken to study the accuracy of CK-MB subforms, troponin I and T, myoglobin, and CK-MB in predicting clinical events at 30 days and 6 months. METHODS: In all, 955 consecutive patients with chest pain were enrolled in a prospective, multicenter, double-blind study to test the prognostic accuracy of these markers. RESULTS: Myocardial infarction was diagnosed in 119 by CK-MB mass criteria and unstable angina (UA) in 203 patients by clinical criteria. Follow-up at 30 days and 6 months was available in 824 and 724 patients, respectively, with mortalities of 2.8 and 4.14%, respectively. Cumulative 6-month mortality was 5.6% in MI, 4.4% in UA, and 3.0% in others. Revascularization was reported in 9.3% of patients by 6 months. A positive test on each of the markers except myoglobin was predictive of revascularization. The composite endpoint of death or revascularization occurred in 107 patients by 6 months and a positive result on each of the markers was predictive of this composite endpoint (p < 0.05). The relative risk of death or revascularization for patients who did not have MI but tested positive on each of the markers was > 1.0 but did not reach statistical significance. CONCLUSIONS: With the possible exception of myoglobin, each of the diagnostic markers displayed similar prognostic performance in patients with chest pain presenting to emergency departments. The most appropriate markers to triage patients with chest pain, which has both adequate early diagnostic sensitivity and prognostic accuracy, are the CK-MB subforms.     

Superiority of combined CK-MB and troponin I measurements for the early risk stratification of unselected patients presenting with acute chest pain

BACKGROUND: Recent studies have suggested that positive troponin I tests are associated with an increased risk of cardiac death during short-term follow-up. However, it is unknown if troponin I tests alone or in addition to CK-MB measurements are superior to predict unfavorable outcome during long-term follow-up. PATIENTS AND METHODS: In a prospective, double-blind study we assessed the prevalence and prognostic value of combined troponin I and CK-MB tests in an unselected cohort of patients (n = 292) admitted to the emergency department for acute chest discomfort. Patients were grouped according to the diagnosis on discharge in those with acute myocardial infarction (1), unstable angina (2), and noncardiac chest pain (3). Six months after enrollment, death rates were obtained and follow-up interviews were performed with respect to survival, recurrence of chest pain, and myocardial infarction. RESULTS: In patients with evidence of coronary heart disease, the mortality rate for abnormal troponin I and normal CK-MB levels was 5.0%. Baseline troponin I and elevated CK-MB levels were associated with a mortality rate of 4.0%. However, the mortality rate was significantly higher (11.1%) in patients presenting with elevated troponin I and CK-MB values. In patients without myocardial infarction on admission, 10.5% with positive troponin I tests died compared to 1.6% with negative tests. The mortality rate in patients without myocardial infarction was 2.7% for patients with elevated CK-MB but normal troponin I values. In patients with both markers elevated a significantly higher mortality rate (16.7%) was found, representing a 6-fold increase in the death event rate. With the additional knowledge of troponin I values, it could be demonstrated that certain cases were misclassified as having noncardiac chest pain. At least some of the latter patients with above-normal values of troponin I were retrospectively to be reclassified as unstable angina. Acute non-Q-wave myocardial infarctions were occasionally misdiagnosed as either angina pectoris or nonischemic chest pain. CONCLUSIONS: Our data suggest the superiority of combined CK-MB and troponin I measurements in clinical practice for the early risk stratification of patients presenting with acute chest pain. In nonmyocardial infarctions, both CK-MB and troponin I convey independent prognostic information with regard to fatal outcome. Troponin I tests in addition to CK-MB measurements contribute to a lower rate of misdiagnoses.     

心肌型脂肪酸结合蛋白(H-FABP)与cTnI、CK-MB组合在诊断早期AMI中的比较

目的研究血清心肌型脂肪酸结合蛋白（H—FABP）在早期急性心肌梗死（AMI）诊断中的价值,比较不同心肌损伤标志物组合诊断早期AMI的价值。方法选择疑似急性冠脉综合征患者102例,采用酶联免疫吸附法（Elisa）测定AMI患者发病1h、2h、3h、4～6h、7～12h时血清H—FABP浓度变化,并与心肌肌钙蛋白I（cTnI）、肌酸激酶同工酶（CK—MB）的检测结果进行比较,分析3种心肌损伤标志物及不同心肌标志物组合H—FABP＋cTnI与H—FABP＋CK—MB在诊断不同发病时间段AMI的敏感性和特异性。结果①在AMI发病3h内,H—FABP的诊断敏感性（66．7％）优于cTnI（0％）和CK—MB（0％）,差异有统计学意义（P〈0．05）。在AMI发病4～6h内,H—FABP的敏感性（94．4％）仍高于cTnI（61．1％）和CK—MB（50％）,差异有统计学意义（P〈0．05）。②H—FABP＋cTnI组合对AMI的诊断敏感度最高（95．8％）,特异度亦最高（100％）。H-FABP＋cTnI组合次之,分别为93．75％和97．2％。这两种组合对AMI的诊断敏感度与单个H—FABP、cTnI和CK—MB比较,差异有统计学意义（P〈0．05）,诊断特异度亦明显升高。结论在AMI发病6h内,H—FABP是最为敏感的心脏标志物,尤以发病3h内最敏感。H—FABP与不同心肌损伤标志物cTnI和CK—MB的组合均具有较高的敏感性和特异性,可提高早期诊断AMI的准确率。