Angiographic correlates of a positive troponin T test in patients with unstable angina

Universal Definition of Myocardial Infarction 99th Percentile versus Diagnostic Cut-off Value of Troponin I for Acute Coronary Syndromes

BACKGROUND

Contemporary diagnosis of ACS and risk stratification are essential for appropriate management and reduction of mortality and recurrent ischemic events, in the acute phase of disease and after hospitalization. The Universal Definition of Myocardial Infarction recommends the detection of troponin levels above the 99th percentile.

OBJECTIVES

To evaluate the occurrence of early death and acute myocardial infarction (AMI) in patients without elevation of troponin (<0.034 ng/mL), patients with mild elevation (above the 99th percentile [>0.034 ng/mL and <0.12 ng/mL)], and patients with significant elevation of troponin (above the diagnostic cutoff for AMI defined by the troponin kit (≥0.12 ng/mL)]; and to analyze the impact of troponin on the indication for invasive strategy and myocardial revascularization.

METHODS

Cross-sectional cohort study of patients with ACS with assessment of peak troponin I, risk score, prospective analysis of 30-day clinical outcomes and two-sided statistical tests, with statistical significance set at p<0.05.

RESULTS

A total of 494 patients with ACS were evaluated. Troponin > 99th percentile and below the cutoff point, as well as values above the cutoff, were associated with higher incidence of composite endpoint (p<0.01) and higher rates of percutaneous or surgical revascularization procedures (p<0.01), without significative difference in 30-day mortality.

CONCLUSIONS

Troponin levels above the 99th percentile defined by the universal definition of AMI play a prognostic role and add useful information to the clinical diagnosis and risk scores by identifying those patients who would most benefit from invasive risk stratification and coronary revascularization procedures.

Predictors of Peak Troponin Level in Acute Coronary Syndromes: Prior Aspirin Use and SYNTAX Score

The peak troponin level has been associated with cardiovascular (CV) mortality and adverse CV events. The association of peak troponin with CV risk factors and severity and complexity of coronary artery disease remains unknown. We assessed the predictors of peak troponin in patients with acute coronary syndrome (ACS). This study aims to determine the predictors of peak troponin in ACS. Cardiac catheterization (CC) reports and electronic medical records from 2010 to 2013 were retrospectively reviewed. A total of 219 patients were eligible for the study. All major CV risk factors, comorbidities, laboratory data, CC indications, and coronary lesion characteristics were included. Univariate and multivariate regression analyses were done. On multivariate linear regression analysis, ST-elevation myocardial infarction (p = 0.001, β = 65.16) and increasing synergy between percutaneous coronary intervention with Taxus and cardiac surgery (SYNTAX) score (p = 0.002, β = 1.15) were associated with higher peak troponin. The Pearson correlation between SYNTAX score and peak troponin was r = 0.257, p = 0.001. History of daily aspirin use was associated with lower peak troponin (p = 0.002, β = -24.32). Prior statin use (p = 0.321, β = -8.98) and the presence of CV risk factors were not associated with peak troponin. Coronary artery disease severity and complexity, urgency of CC, and prior aspirin use are associated with peak troponin levels in ACS. Our findings may help predict patient population with ACS who would be at a greater risk for short- and long-term CV morbidity and mortality due to elevated peak troponin.

"Troponin elevation in coronary ischemia and necrosis"

Detection of a rise and/or fall of cardiac troponin (cTn) is the cornerstone in the diagnosis of myocardial infarction (MI). For the acute risk, it is hypothesized that cTn mirrors activated coagulation and platelet reactivity and indicates the presence of a ruptured plaque, which may help to identify patients at high risk who benefit particularly from aggressive pharmacological treatment and early invasive strategy. High-sensitivity assays using the 99th percentile as the threshold for positivity can achieve sensitivity at presentation of 90 % or more, and performance further improves with subsequent measurements within 3 to 6 h. By 3 h, negative predictive values of almost 100 % have been reported. However, use of assays with higher sensitivity lead ultimately to a loss of clinical specificity. Thus, other conditions than MI, such as stroke, pulmonary embolism, sepsis, acute perimyocarditis, Takotsubo, acute heart failure and tachycardia also can go with elevated troponin levels. The detection of brief rise and subsequent fall of troponin concentration in marathon runners, and even in healthy subjects, after a standardized exercise test has cast doubts on the hypothesis that troponin is released only upon irreversible damage. This kind of troponin leakage may originate from a cytosolic compartment of the cells and not from the necrosis of thin filaments.

Troponins and high-sensitivity troponins as markers of necrosis in CAD and heart failure

For years, cardiac troponins (cTn) have been regarded as the preferred biomarkers for the diagnosis of myocardial infarction and for the risk stratification of patients with acute coronary syndromes, as well as for the selection of patients who need an early invasive strategy, and for the guidance of adjunctive pharmacological therapy. In addition, measurement of cTn has been found useful for detection of myocardial necrosis in conditions unrelated to myocardial ischemia including acute pulmonary embolism, myocarditis, heart failure, sepsis, and end-stage renal disease. In these conditions, an unfavorable prognosis is unequivocally associated with detectable concentrations of cTn.A major limitation of most currently available cTn assays is the lack of adequate precision, i.e., to measure cTn concentrations at the 99th percentile value with a coefficient of variation < 10%. As a consequence, many manufacturers have developed more sensitive cTn assays that now comply with precision criteria required by the Joint European Society of Cardiology/ American College of Cardiology/American Heart Association/World Heart Federation Task Force for the Redefinition of Acute Myocardial Infarction.Using assays with higher analytic sensitivity more patients will be seen in clinical practice with the high-sensitivity cardiac troponin T (TnThs) above the 99th percentile discriminator. The causes of these elevations may be due to acute, subacute and chronic cardiac disease such as heart failure or cardiomyopathies.

Prognostic value of megatroponinemia after myocardial infarction

PURPOSE

The purpose of this study is to investigate the prognostic value of megatroponinemia (troponins >100 ng/mL), as a predictor of major adverse cardiac events such as recurrent angina, myocardial infarction, and death in patients presenting with acute myocardial infarction.

METHODS

Over a period of 2 years, we identified 27 patients admitted with acute myocardial infarction and troponin I values >100 ng/mL. These patients were followed-up for the short term during their hospitalization as well as for an intermediate term of 18+/-14 months after their initial presentation with acute myocardial infarction for major adverse cardiac events including recurrent angina, myocardial infarction, and death.

RESULTS

Of the 27 patients, one died 5 days after myocardial infarction and 26 were discharged home in stable condition, with few requiring timely intervention. Six patients were lost to follow-up. Five patients died during follow-up, 4 from recurrent myocardial infarction and 1 died from metastatic renal cell carcinoma. Twelve patients had non-fatal myocardial infarction, with 10 being acute ST elevation; 3 patients had recurrent angina.

CONCLUSION

Patients presenting with an acute myocardial infarction and troponins >100 ng/mL have continued incremental risk of excessive major adverse cardiac events during short and intermediate follow-up period.

Diabetes exacerbates angiographic coronary lesion progression in subjects with metabolic syndrome independent of CRP levels

BACKGROUND

Metabolic syndrome is gaining more attention as a special cluster of cardiovascular risks. However, its role, with or without diabetes, in predicting atherosclerosis progression, remains largely undetermined. We investigated the predictors for angiographic coronary atherosclerosis progression in patients with metabolic syndrome and angina pectoris.

METHODS

Patients with metabolic syndrome and angina pectoris who underwent repeat coronary angiograms and had serum samples at the time of first catheterization were enrolled for analysis (N=113). A modified Gensini scoring system was used to define CAD progression between the index and follow-up angiograms. Those who had significant angiographic progression of coronary disease were classified as the progression group (N=42) and those who did not as the non-progression group (N=71).

RESULTS

There were more cases of diabetes mellitus (52% vs. 31%, p=0.040) in the CAD progression group. The progression group also had higher baseline fasting blood glucose (150+/-73 vs. 117+/-46 mg/dl, p=0.010) but similar LDL cholesterol (114+/-38 vs. 109+/-33 mg/dl, p=0.421) than the non-progression group. In terms of inflammatory markers, there was no difference in hs-CRP (p=0.208), MCP-1 (p=0.514), or sCD40L (p=0.549) between the groups. In binary logistic regression, diabetes mellitus remained a significant predictor of CAD progression (OR 2.43, p=0.030) for patients with metabolic syndrome and angina pectoris, but hs-CRP and LDL-C were not.

CONCLUSION

Diabetes mellitus, but not inflammatory marker hs-CRP or LDL-C, is a significant predictor of angiographic CAD progression in patients with metabolic syndrome and angina pectoris.

Decreased circulating protective adiponectin level is associated with angiographic coronary disease progression in patients with angina pectoris

Adipocyte cytokines regulate glucose metabolism and insulin resistance and adiponectin is thought to have a protective effect against atherosclerosis. Studies have shown that adiponectin expression is decreased in obese subjects and those with metabolic syndrome or diabetes mellitus. The purpose of this study was to investigate the relationship between circulating adipocyte cytokine concentrations and angiographic coronary artery disease (CAD) progression in patients with chest pain. Patients with stable angina pectoris who underwent repeat coronary angiograms and had serum samples at the time of first catheterization between March 1999 and January 2004 were enrolled. A modified Gensini scoring system was used to define angiographic coronary artery progression between the index and follow-up angiograms. Those who had significant angiographic progression of coronary lesions were classified into the progression group (N=55). Those who did not have CAD progression were classified into the non-progression group (N=102). Univariate analysis showed that CAD progression was associated with male gender (93% vs. 78%, p=0.038), higher baseline total cholesterol (187+/-43 vs. 173+/-39 mg/dl, p=0.037) and higher baseline fasting blood glucose (128+/-57 vs. 110+/-40 mg/dl, p=0.037). Patients in the progression group had a significantly lower serum adiponectin level (14.3+/-7.9 vs. 18.9+/-13.2 mug/ml, p=0.007) than, but resistin (28.9+/-13.4 vs. 34.4+/-26.0 ng/ml, p=0.142) and leptin (7.4+/-4.6 vs. 7.7+/-6.5 ng/ml, p=0.675) levels similar to, those in the non-progression group. In a multivariate binary logistic regression model, male gender (odds ratio 4.283, p=0.015), higher serum cholesterol (odds ratio 1.010, p=0.032) and lower serum adiponectin (odds ratio 0.959, p=0.030) were all significant independent predictors of CAD progression. In conclusion, we found that a decreased circulating level of adiponectin is associated with angiographic CAD progression in patients with angina pectoris.

The effects of facilitated primary PCI by guide wire on procedural and clinical outcomes in acute ST-segment elevation myocardial infarction

BACKGROUND

Reperfusion of the infarct related artery (IRA) prior to PCI is prognostically important in patients with acute ST segment elevation myocardial infarction (STEMI). Reperfusion is either achieved spontaneously, facilitated by GP IIb/ IIIa inhibitors, or mechanically by crossing the guide wire beyond the lesion. In order to test the hypothesis that a visible coronary anatomy is independently associated with procedural and clinical outcomes, we evaluated the frequency and prognostic impact of guide wire facilitated reperfusion of the IRA before primary PCI.

METHODS AND RESULTS

We enrolled 311 consecutive patients with successful primary PCI for STEMI (TIMI grade > or =2 flow) within 12 h after onset of symptoms. Among these, 90 patients (28.9%) had a spontaneously reperfused IRA on initial angiogram, 56 patients (18.0%) achieved reperfusion after crossing of the guide wire, and 165 patients (53.1%) successful reperfusion only after PCI. Variables associated with successful guide wire facilitated reperfusion were younger age, no history of arterial hypertension, active smoking status, negative cardiac troponin T on admission, and an infarct in the territory of the right coronary artery. Patients with spontaneous reperfusion or reperfusion after crossing of the guide wire required less fluoroscopic time and less contrast material during angiography and had higher procedural success rates (TIMI grade 3 flow 91.1 vs 79.4%, p=0.048) than patients without initial reperfusion. In addition, patients with reperfusion after crossing the lesion with the guide wire had lower mortality rates at 30 days (3.6 vs 9.1%) and after a median of 16 months (3.6 vs 13.9%, p=0.03) than those with reperfusion after PCI.

CONCLUSIONS

Reperfusion of an occluded IRA by crossing the guide wire is associated with higher procedural success rates and better outcomes. Better roadmapping and device selection represent potential reasons but the exact mechanism for these benefits is still illusive.

Coronary artery disease progression is associated with C-reactive protein and conventional risk factors but not soluble CD40 ligand

BACKGROUND

Coronary artery disease (CAD) is a major cause of death worldwide. Epidemiological studies have documented conventional risk factors; however, no studies to date have addressed the roles of soluble CD40 ligand (sCD40L) and monocyte chemoattractant protein-1 (MCP-1), and there have been few reports on other novel risk factors in CAD progression. The aim of the present study was to explore the roles of novel and conventional risk factors in CAD progression.

METHODS

Patients with stable angina pectoris who underwent repeat coronary angiograms and had serum samples at the time of their first catheterization between March 1999 and January 2004 were enrolled. Those who had progression of coronary atherosclerosis were classified into the progression group (n = 66). Those who did not have CAD progression were classified into the nonprogression group (n = 124).

RESULTS

There were more cases of diabetes mellitus (36% versus 20%; P = 0.024) and more men (92% versus 81%; P = 0.040) in the CAD progression group than in the nonprogression group, respectively. The progression group also had poorer lipid profiles than the nonprogression group, including higher total cholesterol (188+/-42 mg/dL versus 173+/-39 mg/dL, respectively; P = 0.014) and low density lipoprotein cholesterol (122+/-38 mg/dL versus 112+/-36 mg/dL, respectively; P = 0.025). In terms of inflammatory markers, progression patients had higher baseline high-sensitivity C-reactive protein (hs-CRP) concentrations (P = 0.018), which was also related to the subsequent angiographic severity score changes; however, sCD40L (6182+/-4352 pg/mL versus 6244+/-4602 pg/mL; P = 0.961), MCP-1 (427+/-540 pg/mL versus 341+/-128 pg/mL; P = 0.580) and adhesion molecules concentrations were indifferent between the progression group and the nonprogression group, respectively. Using a multivariate logistical regression model, the ORs for predicting progression were 2.19 for diabetes mellitus, 2.04 for hypercholesterolemia and 1.52 for hs-CRP (P < 0.05).

CONCLUSION

In the present study, only conventional risk factors, and particularly hs-CRP, were markers for predicting CAD progression. Novel risk factors, such as concentrations of sCD40L, MCP-1 and adhesion molecules, did not play significant roles.

Association between cardiac troponin T elevation and angioscopic morphology of culprit lesion in patients with non-ST-segment elevation acute coronary syndrome

BACKGROUND

It is well known that cardiac troponin T (TnT) elevation on admission indicates a high-risk subgroup among patients with non-ST-segment elevation acute coronary syndrome (NSEACS). Although the mechanism of TnT elevation is speculated to be the microthromboembolism from unstable plaques, it has not been clarified. The aim of this study is to clarify the association between the serum TnT elevation and the angioscopically evaluated morphology of culprit lesion in the patients with NSEACS.

METHODS

Among 113 patients with NSEACS who had significant coronary stenosis, 62 patients with successful angioscopic examination were prospectively and consecutively enrolled from October 2001 to August 2002. Patients were divided into 2 groups according to the serum TnT level measured before percutaneous coronary intervention: TnT-positive or TnT-negative group. Thrombus and plaque color at culprit lesion were evaluated by angioscopy and were compared between the groups. Plaque color was determined as yellow or white, and thrombus as none, small, or large. Three different definitions for TnT-positive (> or =0.1, > or =0.03, and > or =0.01 ng/mL) were used and the sensitivity and specificity for detecting thrombus was compared.

RESULTS

Prevalence of thrombus, large thrombus, and yellow plaque were all higher in TnT-positive than in TnT-negative group for 3 different cutoff values of TnT. Angiographic slow-flow occurred more frequently after percutaneous coronary intervention in TnT-positive than in TnT-negative group for 3 different cutoff values of TnT. Sensitivity/specificity of detecting large thrombus were 33%/100%, 44%/91%, and 56%/83% when TnT-positive was defined as TnT > or = 0.1, > or =0.03, and > or =0.01 ng/mL, respectively.

CONCLUSIONS

Serum TnT level was significantly associated with the prevalence of thrombus and yellow plaque at the culprit lesions of NSEACS. Troponin T, when positive was defined as > or =0.01 ng/mL, still have a high specificity for detecting intracoronary thrombus.

Predictors of left main or three-vessel disease in patients who have acute coronary syndromes with non-ST-segment elevation

To identify an early, simple, noninvasive predictor of left main (LM) or 3-vessel disease (3-VD), we retrospectively studied clinical variables on admission in 310 patients with acute coronary syndromes with non-ST-segment elevation. Univariate analysis indicated that many factors were related to LM/3-VD. Multivariate analysis showed that ST-segment elevation in lead aVR of >/=0.5 mm was the strongest predictor of LM/3-VD, followed by positive troponin T (odds ratio 19.7, p <0.001, and odds ratio 3.08, p = 0.048, respectively). ST-segment elevation in lead aVR of >/=0.5 mm and positive troponin T identified LM/3-VD with sensitivities of 78% and 62%, specificities of 86% and 59%, positive predictive values of 57% and 26%, and negative predictive values of 95% and 87%, respectively (p <0.05). Our findings suggest that in patients with non-ST-segment elevation acute coronary syndromes, ST-segment elevation in lead aVR of >/=0.5 mm and positive troponin T on admission (especially the former) are useful predictors of LM/3-VD.

Elevations in troponin I after percutaneous coronary interventions are associated with abnormal tissue-level perfusion in high-risk patients with non-ST-segment-elevation acute coronary syndromes

BACKGROUND

In the setting of non-ST-segment-elevation (NSTE) acute coronary syndromes (ACS), the pathophysiological mechanisms underlying post-percutaneous coronary intervention (PCI) cardiac troponin I (cTnI) elevation remain unclear.

METHODS AND RESULTS

We evaluated the relationship between troponin elevation and tissue-level perfusion using the TIMI flow grade, corrected TIMI frame count, TIMI myocardial perfusion grade (TMPG), and myocardial contrast enhancement by intracoronary myocardial contrast echocardiography (MCE) before and immediately after PCI performed within 24 to 48 hours of hospital admission in 42 high-risk (angina at rest, unequivocal ST-segment depression, and cTnI elevation) patients with NSTE-ACS. All patients were treated with glycoprotein IIb/IIIa inhibitors (27 with tirofiban and 15 with abciximab) and had successful PCI. Fourteen patients had a postprocedural cTnI elevation, whereas 28 did not. TMPG 0/1 after PCI was observed more frequently in patients with postprocedural cTnI elevation (43% versus 7%; P<0.02). cTnI levels were higher among patients with TMPG 0/1 versus patients with TMPG 2/3 (5.3+/-2.7 versus 1.5+/-1.3 ng/mL; P<0.0001). Patients with postprocedural cTnI elevation also presented a significantly lower number of perfused segments at MCE (59% versus 81%; P=0.02) as well as a lower MCE score index (0.65+/-0.38 versus 0.89+/-0.21; P<0.02).

CONCLUSIONS

Postprocedural cTnI elevation in high-risk patients with NSTE-ACS is associated with an abnormal tissue-level perfusion.

Elevations in troponin T and I are associated with abnormal tissue level perfusion: a TACTICS-TIMI 18 substudy. Treat Angina with Aggrastat and Determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis in Myocardial Infarction

BACKGROUND

Cardiac troponin T (cTnT) and I elevations are associated with a higher risk of adverse events, a higher incidence of multivessel disease, complex lesions, and visible thrombus in the setting of non-ST elevation (NSTE) acute coronary syndromes (ACS). Other pathophysiological mechanisms underlying troponin elevation remain unclear.

METHODS AND RESULTS

We evaluated the relationship between troponin elevation and tissue level perfusion using the TIMI myocardial perfusion grade (TMPG) in 310 patients with NSTE-ACS in the Treat Angina with Aggrastat and Determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis in Myocardial Infarction (TACTICS-TIMI) 18 trial. TMPG 0/1 ("closed" microvasculature) was observed more frequently in cTnT-positive patients both before (58.1% versus 42.1%; P=0.007) and after percutaneous coronary intervention (55.4% versus 35.6%; P=0.004). cTnT levels were higher among patients with TMPG 0/1 versus patients with TMPG 2/3 (0.50 versus 0.31 ng/mL; P=0.006). cTnT-positive patients were more likely to have thrombus (42.5% versus 29.3%), tighter stenoses (72.0% versus 64.8%), and higher rates of TIMI flow grade 0/1 (15.6% versus 7.0%; all P<0.05). TMPG 0/1 remained independently associated with cTnT elevation (odds ratio, 1.81; P=0.02), even after adjusting for epicardial TIMI flow grade, presence of thrombus, and prior myocardial infarction. TMPG 0/1 flow both before and after intervention was associated with increased risk of death or myocardial infarction at 6 months.

CONCLUSIONS

Similar to what has been observed in the setting of ST-elevation myocardial infarction, abnormal tissue level perfusion is also associated with adverse outcomes in the NSTE-ACS setting. Independent of the presence of thrombus and abnormal flow in the epicardial artery, impaired tissue level perfusion is associated with a 1.8-fold increased risk of cTnT elevation.