Exclusion Of Myocardial Infarction Research Articles

Abstract 12816: Single High-Sensitivity Point of Care Whole Blood Cardiac Troponin I Measurement to Rule Out Acute Myocardial Infarction at Low Risk

Introduction: High-sensitivity cardiac troponin (hs-cTn) laboratory assays are used to rule out myocardial infarction (MI) on presentation, but prolonged result turn-around times can delay patient management. Hypothesis: Our aim was to identify patients at low risk of index MI using a rapid, point of care (POC), whole blood hs-cTnI assay at presentation, with potential early patient discharge, with < 1% risk of adverse events. Methods: Consecutive emergency department patients from two prospective, observational studies with suspected acute coronary syndrome were enrolled. A POC hs-cTnI assay (Siemens Atellica ® VTLi) threshold using whole blood at presentation, that resulted in a negative predictive value (NPV) of ≥99.5% and sensitivity of > 99% for index MI, was derived (SEIGE) and validated using plasma (SAMIE). Event adjudications were established using hs-cTnI assay results from usual clinical care. The primary outcome was MI at 30-days. Results: 1086 patients (8.1% MI) were enrolled in a US derivation cohort (SEIGE) and 1486 (5.5% MI) in an Australian validation cohort (SAMIE). A derivation whole blood POC hs-cTnI concentration of <4ng/L provided a NPV of 99.5% (95% CI: 97.2-100%) and sensitivity of 98.9% (93.8-100%) for ruling out MI. In the validation cohort, NPV was 99.8% (99.1-100%) and sensitivity 98.8% (93.3-100%). 17.8% and 41.8%, respectively, were defined as low risk for discharge. 30-day adverse cardiac events were 0.1% (n=1) for SEIGE and 0.8% (n=5) for SAMIE. Conclusions: A point-of-care, whole blood hs-cTnI assay permits an accessible, rapid and safe exclusion of MI, and expedites discharge from the emergency department.

Saudi Heart Association Position Statement on the Use of Biomarkers for the Management of Heart Failure and Acute Coronary Syndrome.

BackgroundThe burden of acute coronary syndrome (ACS) and heart failure (HF) remains high in Saudi Arabia. Biomarkers can greatly improve the management and outcomes of these conditions, but no official guidance is available on their use in Saudi Arabia.Consensus panelAn expert panel of cardiologists, interventional cardiologists and cardiac surgeon reviewed available evidence and formulated recommendations relevant to clinical practice in Saudi Arabia.Consensus findingshigh-sensitivity cardiac troponins play a major role in the diagnosis of ACS and the exclusion of myocardial infarction in patients with HF. Natriuretic Peptides are recommended to determine the likelihood of a diagnosis of HF in a chronic setting and rapidly exclude HF in an acute setting. High-sensitivity cardiac troponins and NT-proBNP have good prognostic ability in ACS and HF. These biomarkers could also facilitate discharge planning and reduce unnecessary hospital admissions and resource wastage. The use of biomarkers should not be excessive and should abide by appropriateness criteria. High-sensitivity assays and NT-proBNP measurements are preferred.ConclusionBy outlining expert recommendations on the best practices in the use of biomarkers, the panel hopes to contribute towards a recognized updated guidance for all healthcare providers in Saudi Arabia on the evidence-based management of HF and ACS.

Bilateral spontaneous pneumothorax in a non-intubated COVID-19 patient

Spontaneous bilateral pneumothorax is a rare condition occurring only in 1,3% of cases of spontaneous pneumothorax. Although spontaneous pneumothorax is recognized complication of COVID it is usually associated with severe cases of COVID pneumonia with massive lung involvement and a high level of inflammatory cytokines – so called "inflammatory storm". Large percentage of this patients requires life support with mechanical ventilation and pneumothorax is usually accompanied with pneumomediastinum. Nevertheless occurrence of spontaneous pneumothorax in non-intubated patients is very low. Therefore the presented case is exceptional in two ways – spontaneous pneumothorax occurred in non-intubated patient and is presented bilaterally. Early diagnosis of spontaneous bilateral pneumothorax can pose a diagnostic dilemma as it mimics progression of lung involvement in the course of COVID, pulmonary embolism or myocardial infarction. In our case apart from COVID pneumonia, patient had typical clinical presentation of myocardial infarction and known coronary artery disease, which initially mislead clinicians toward diagnosis of myocardial infarction (MI). However after exclusion of MI, chest radiograph was requested which revealed bilateral pneumothorax. The exact mechanism of pneumothorax development in non-intubated patients is not clear. Lung inflammation in COVID causes formation of pneumatocele, which can predispose to spontaneous pneumothorax. It is important to note that our patient developed pneumothorax without evident pneumatocele, underlying lung condition or history of trauma. This case shows that bilateral pneumothorax in COVID-19 can develop also in patients with only mild clinical course of COVID pneumonia. Early diagnosis and proper management is essential and can prevent life-threatening complications.

Reducing avoidable chest pain admissions and implementing high-sensitivity troponin testing

NHS accident and emergency departments see 0.5 million patients presenting with a cardiac condition each year. The accurate assessment of chest pain and subsequent diagnosis or exclusion of myocardial infarction...

Troponins as biomarkers for myocardial injury and myocardial infarction

Elevation of cardiac troponins above the 99th percentile of ahealthy reference population is established as a marker for myocardial cell damage and is crucial for the diagnosis of myocardial infarction. In addition, corresponding clinical evidence of acute myocardial ischemia i.e. symptoms, changes in the electrocardiogram (ECG), wall motion abnormalities or suggestive angiographic findings are required for the diagnosis of myocardial infarction. Using modern highly sensitive assays myocardial infarction can be detected more frequently and earlier. On the other hand myocardial infarction can be ruled out with ahigher diagnostic accuracy. Cardiac troponins are specific for myocardial cell damage but not for myocardial infarction and can be elevated in numerous other disease states. In these cases myocardial injury can be diagnosed independently of myocardial ischemia. Typical dynamics with rise and fall of troponin levels can distinguish acute myocardial injury (e. g. pericarditis/myocarditis and pulmonary embolism) from chronic myocardial injury (e. g. cardiomyopathy). Clinically, highly sensitive troponin assays are currently recommended in addition to the 0/3 h and 0/1 h algorithms for rapid inclusion or exclusion of myocardial infarction.

Myocardial perfusion scintigraphy in the diagnostics of takotsubo syndrome

We analyzed the publications about single-photon emission computed tomography in the diagnostics of takotsubo syndrome; the dynamics of testing data are presented on a clinical example. Single-photon emission computed tomography can be used to evaluate perfusion parameters for exclusion of myocardial infarction in uncertain cases. In segments with impaired contractile function, it is possible to detect normal or reduced perfusion. During the acute phase there is a reduced accumulation of radiopharmaceuticals in myocardial segments with impaired function, which coincides with the regional distribution of neuronal activity. Pathological changes may persist for several months, and use of scintigraphy with a radiopharmaceutical may help in cases when the diagnosis was not well-timed established. The method of myocardial scintigraphy in ECG-synchronized tomography allows to simultaneously assess the perfusion and the function of the left ventricle and differentiate such disorder as takotsubo syndrome.

PMD4 - Cost-Effectiveness Analysis of High-Sensitivity Troponin T Versus Conventional Troponin I Testing for Acute Myocardial Infarction

High-sensitivity cardiac troponin T (hs-TnT) assays have improved early diagnostic accuracy of myocardial infarction (MI). The safety of hs-TnT based 0-hour/1-hour algorithm for early exclusion of MI in suspected patients has been validated in several studies. However, the cost-effectiveness of the 0-hour/1-hour algorithm as compared to the conventional diagnosis pathway has not been fully analyzed, especially in the healthcare settings of the Asian countries. We conducted a cost-effectiveness analysis from a third-party payer perspective using Asian data. We designed a clinical decision model to evaluate the cost-effectiveness (CE) of the 0-hour/1-hour algorithm. Effectiveness or efficacy data were abstracted from the a Japan-Taiwanese validation study, healthcare process and human resources data were extracted from the electronic medical record database of a tertiary hospital in Taiwan, and cost data were derived from the National Health Insurance Research Database of Taiwan from 2011 to 2013. The clinical outcomes were measured by quality-adjusted life year (QALY). Monte Carlo simulation was used to derive incremental cost-effectiveness ratio (ICER) estimates with confidence intervals. We plotted the pairs of incremental costs and QALYs on the CE plane. Compared to conventional diagnostic pathway, the 0-hour/1-hour accelerated diagnosis algorithm resulted in fewer overnight emergency department stays (60.3% vs. 24.1%), fewer cardiology referrals (32.4% vs. 20.9%), and lower healthcare human resources ($11,236.80 vs. $8,528.20 USD). Use of hs-cTnT was associated with an ICER of [$14,082.40] per QALY gained. The majority of incremental cost-QALY pairs fall in the dominant quadrant of the CE plane, indicating that using hs-cTnT is cost-saving with better outcomes. The 0-hour/1-hour algorithm based on hs-TnT assays is cost effective in the Taiwanese healthcare setting.

Type A Intramural Hematoma Often Turns Out To Be a Type A Dissection

The management of type A intramural hematoma (IMH) is controversial. Although most Western countries still recommend immediate surgical repair, some centers in Asia have shown good results recently with medical treatment alone. Here, we present a case of type A IMH which was discovered during the operation to be a thrombosed type A dissection. An 83-year-old female patient presented with acute chest pain. After diagnostic exclusion of myocardial infarction, computed tomography was performed, which showed an IMH from the ascending to the descending aorta. No intimal flap could be detected. The ascending aorta was replaced surgically with a prosthesis. During the operation, we found a ruptured intimal plaque, which had caused dissection of the aorta with thrombosis of the false lumen. The true diagnosis-thrombosed type A dissection and not IMH-was revealed neither by computed tomography nor by transesophageal echocardiography. Type A IMH should still be treated with immediate surgical repair because in many cases it turns out to be thrombosed type A dissection.

Comparison of contemporary troponin assays with the novel biomarkers, heart fatty acid binding protein and copeptin, for the early confirmation or exclusion of myocardial infarction in patients presenting to the emergency department with chest pain

ObjectiveTo examine the diagnostic accuracy of novel biomarkers of myocardial injury and troponin assays for diagnosis of myocardial infarction.Methods850 patients randomised to the point-of-care testing arm of the Randomised Assessment...

Not such a rarity: takotsubo cardiomyopathy as a mimic of ST elevation myocardial infarction

Purpose: Takotsubo Cardiomyopathy (TTC) was initially thought to be a rare disorder predominantly presenting like ST elevation myocardial infarction (STEMI). However, recent data suggests that TTC may occur relatively commonly, especially among ageing women, and STEMI-like changes may not represent the major mode of presentation of TTC. We therefore sought to evaluate (1) the incidence of STEMI- like TTC among women > 50 years (2) the proportion of recognized TTC cases presenting as STEMI. Methods: Four years' data from 2 major tertiary referral hospitals were audited. Diagnosis of TTC was based on (1) typical left ventricular wall motion anomalies (2) exclusion of myocardial infarction, and (3) demonstration of typical inflammatory changes. Results: During the period concerned 1,426 patients presented as including 343 women of whom 98% were >50 years old. TTC was diagnosed in 9.3% of women older than 50 years presenting with STEMI. Of the total TTC cases over four years, 29 women (26%) presented as STEMI. Despite the relatively stable prevalence of TTC, the proportion of TTC cases mimicking STEMI increased over the evaluation period (Figure). Presentation with STEMI-like TTC was also associated with marginally greater extensive wall motion anomalies (p=0.07) and similar NT pro BNP release. ![Figure][1] Figure 1 Conclusion: (1) Presentation of TTC occurs more frequently without ST elevation. (2) Among women >50 years presenting with STEMI, TTC accounts for approximately 9.3% of cases. Therefore improved diagnostic algorithms for earlier diagnosis of the subset are required. [1]: pending:yes

Not Such a Rarity! Takotsubo Cardiomyopathy as a Mimic of ST Elevation Myocardial Infarction

Purpose: Takotsubo Cardiomyopathy (TTC) was initially thought to be a rare disorder predominantly presenting like ST elevation myocardial infarction (STEMI). However, recent data suggests that TTC may occur relatively commonly, especially among ageing women, and STEMI-like changes may not represent the major mode of presentation of TTC. We therefore sought to evaluate (1) the incidence of STEMI- like TTC among women > 50 years (2) the proportion of recognized TTC cases presenting as STEMI. Methods: Four years' data from 2 major tertiary referral hospitals were audited. Diagnosis of TTC was based on (1) typical left ventricular wall motion anomalies (2) exclusion of myocardial infarction, and (3) demonstration of typical inflammatory changes. Results: During the period concerned 1,426 patients presented as including 343 women of whom 98% were >50 years old. TTC was diagnosed in 9.3% of women older than 50 years presenting with STEMI. Of the total TTC cases over four years, 29 women (26%) presented as STEMI. Despite the relatively stable prevalence of TTC, the proportion of TTC cases mimicking STEMI increased over the evaluation period (Figure). Presentation with STEMI-like TTC was also associated with marginally greater extensive wall motion anomalies (p=0.07) and similar NT pro BNP release. ![Figure][1] Figure 1 Conclusion: (1) Presentation of TTC occurs more frequently without ST elevation. (2) Among women >50 years presenting with STEMI, TTC accounts for approximately 9.3% of cases. Therefore improved diagnostic algorithms for earlier diagnosis of the subset are required. [1]: pending:yes

Cholesteryl esters associated with acyl-CoA:cholesterol acyltransferase predict coronary artery disease in patients with symptoms of acute coronary syndrome.

Identifying the likelihood of a patient having coronary artery disease (CAD) at the time of emergency department (ED) presentation with chest pain could reduce the need for stress testing or coronary imaging after myocardial infarction (MI) has been excluded. The authors aimed to determine if a novel cardiac biomarker consisting of plasma cholesteryl ester (CE) levels typically derived from the activity of the enzyme acyl-CoA:cholesterol acyltransferase (ACAT2) are predictive of CAD in a clinical model. A single-center prospective cohort design enrolled participants with symptoms of acute coronary syndrome (ACS) undergoing coronary computed tomography angiography (CCTA) or invasive angiography. Plasma samples were analyzed for CE composition with mass spectrometry. The primary endpoint was any CAD determined at angiography. Multivariable logistic regression analyses were used to estimate the relationship between the sum of the plasma concentrations from cholesteryl palmitoleate (16:1) and cholesteryl oleate (18:1) (defined as ACAT2-CE) and the presence of CAD. The added value of ACAT2-CE to the model was analyzed comparing the C-statistics and integrated discrimination improvement (IDI). The study cohort was composed of 113 participants with a mean (± standard deviation [SD]) age of 49 (±11.7) years, 59% had CAD at angiography, and 23% had an MI within 30 days. The median (interquartile range [IQR]) plasma concentration of ACAT2-CE was 938 μmol/L (IQR = 758 to 1,099 μmol/L) in patients with CAD and 824 μmol/L (IQR = 683 to 998 μmol/L) in patients without CAD (p = 0.03). When considered with age, sex, and the number of conventional CAD risk factors, ACAT2-CE levels were associated with a 6.5% increased odds of having CAD per 10 μmol/L increase in concentration. The addition of ACAT2-CE significantly improved the C-statistic (0.89 vs. 0.95, p = 0.0035) and IDI (0.15, p < 0.001) compared to the reduced model. In the subgroup of low-risk observation unit patients, the CE model had superior discrimination compared to the Diamond-Forrester classification (IDI = 0.403, p < 0.001). Plasma levels of ACAT2-CE have strong potential to predict a patient's likelihood of having CAD when considered in a clinical model but not when used alone. In turn, a clinical model containing ACAT2-CE could reduce the need for cardiac imaging after the exclusion of MI.

Ischemia-modified albumin: We are ready for use in the emergency room?

We read the article by Shen et al.[1] about the assessment of ischemia-modified albumin (IMA) for emergency room diagnosis of acute coronary syndrome (ACS). We would like to point out some important aspect of the potential usefulness of serum IMA measurement in patients presenting to the emergency room with acute chest pain are suffering ACS. Most patients brought to the hospital with chest pain and suspected of ACS are eventually ruled out for acute myocardial infarction and active unstable coronary disease. The ideal role of an ischemia marker would thus be as a rule out test. The most logical place to use such a test is in the emergency department [2]. Not all investigators consider the diagnostic performance of IMA either alone or in combination with cardiac troponin, or other biomarkers of necrosis, to be adequate [3]. Recently, a large study prospectively on 248 patients presenting emergency department with symptoms suggestive of ACS did not support the use of IMA as a negative predictor for ACS. All patients had positive IMA results using the 85 U/ml cut-off value recommended by the manufacturer. Receiver operating characteristic curves failed to show improved cut-off points for diagnosis raised 12 h troponin levels or ACS, and the area under the curve was 0.52 and 0.53, respectively [4]. Likewise, Hjortshoj et al.[5] enrolled 107 subjects admitted with suspected ACS, where the sensitivity of admission IMA for a final diagnosis of ACS was 86%, a specificity of 49% and a negative predictive value of 88%. For efficient provision of care in the emergency department, a high negative predictive value may be most critical, for while false negatives are undesirable, true negatives are greater importance, because the correct exclusion of myocardial infarction preserves limited and expensive resources [3]. Although the main limitation of IMA at present is its low specificity, it may be a useful test to rule out ACS from low to moderate pre-test probability conditions with negative cardiac troponins and a negative electrocardiogram. As with any new marker, there are several issues and limitations that require caution: its cardiospecificity, its kinetics during the first hours after ACS, and the optimal cutpoint for clinical validation [6]. Further studies are required to investigate the role of IMA in cardiac ischemic diseases in the emergency department setting. An example is the large multicenter randomised controlled trial evaluating the utility of IMA for risk stratification in 1250 patients presenting with chest discomfort and possible ischemic heart disease, and to evaluate the diagnosis and prognostic implication for IMA for major adverse cardiac events (the IMAgine trial NCT00355992). This probably will provide a definitive answer. Therefore, a test like IMA may be enormously valuable to the emergency physician assessing chest pain patients but we require a better understanding on this marker before it is ready for use. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology (Shewan and Coats 2010;144:1–2).

Enhancing the Diagnostic Performance of Troponins in the Acute Care Setting

Current guidelines define cardiac troponin I (TnI) as an indicator of necrosis when the concentration exceeds the 99% upper limit of a healthy reference population, a reference value near the assay's lowest detectable level. We assessed the utility of a modified TnI cutoff point derived from a population at low risk for coronary artery disease (CAD) and evaluated its utility in determining acute myocardial infarction (MI). A modified TnI cutoff point was derived by the receiver operating characteristic (ROC) curve from 737 consecutive patients who underwent serial TnI measurements for exclusion of MI. Creatinine kinase isoenzyme MB (CK-MB) evolutionary change was used to define MI. The new derived cutoff point was validated using another subset of 320 patients who were evaluated for MI. ROC-derived TnI cutoff point (A) was 0.65 μg/L, and its performance was compared to the recommended cutoff point ([B] 0.15 μg/L). Cutoff point A had greater specificity (94.5% vs. 86.9%, p < 0.001) but slightly lower sensitivity (96.5% vs. 100%, p < 0.01). Cutoff point A provided significantly greater positive predictive value (PPV) for MI (74.1% vs. 55.5%, p < 0.0001) and fewer false-positive errors, while preserving comparable negative predictive value (NPV) (98.9% vs. 100%). A higher cutoff point derived from a reference population of patients at low risk for CAD may improve the TnI performance assay. The PPV for diagnosis of MI was significantly higher and false-positive values were fewer without affecting the NPV. The more reliable diagnosis of MI may have resulted, which, in turn, may have significant clinical and economic implications.

Predictive power of systolic function and congestive heart failure in patients with patients admitted for chest pain without ST elevation in the troponin era

Impaired systolic function and congestive heart failure (CHF) are powerful predictors of adverse outcomes in patients with myocardial infarction (MI). However, there are little data in which both of these variables were assessed in heterogenous patients admitted from the emergency department for exclusion of ischemia. Consecutive patients admitted for MI exclusion who had ejection fraction (EF) measured were included. Systolic dysfunction was defined as EF <40%. Congestive heart failure was diagnosed based on clinical or x-ray evidence in the first 24 hours. Multivariate analysis was used to determine predictors of 30-day and 1-year mortality. Of the 4,343 consecutive patients admitted, 3,682 (85%) had EF assessed (including 97% of the troponin I [TnI]-positive patients) and were included. One-year unadjusted mortality was 9.5%, but in the presence of systolic dysfunction or CHF, it increased to 22% and 26%, respectively. The most important multivariate predictors of 30-day and 1-year mortality were similar and included CHF (OR for 1-year mortality 2.5, 95% CI 1.9-3.4), TnI elevations (OR 2.0, 95% CI 1.5-2.6), and severe renal failure (OR 5.2, 95% CI 3.7-7.2). Systolic dysfunction was predictive of 1 year (OR 1.9, 95% CI 1.4-2.5) but not 30-day mortality. Results were similar in the 3,018 patients who were troponin-negative. Congestive heart failure is an independent predictor of both short- and long-term mortality in patients admitted for MI exclusion. In contrast, systolic dysfunction predicts long-term but not short-term mortality. One cannot be used as a surrogate for the other.

Ability of myoglobin to predict mortality in patients admitted for exclusion of myocardial infarction

Background Myoglobin can be used as an early marker to diagnose myocardial infarction (MI); and although nonspecific for myocardial necrosis, it seems to be a strong mortality predictor. Because myoglobin elevations are often present in patients with renal insufficiency, it is possible that the predictive value of myoglobin is secondary to identifying patients with renal insufficiency. Methods Consecutive patients admitted for MI exclusion without ST elevation on the initial electrocardiogram underwent serial assessment of cardiac markers (creatine kinase [CK], CK–myocardial band [MB], and troponin I [TnI]). Myoglobin was assessed at the time of admission and/or 3 hours later. Renal insufficiency was defined as a creatinine clearance <60 mL/min. Multivariate analysis was performed to identify predictors of 30-day and 1-year all-cause mortality. Results A total of 3461 patients were included in the analysis. Overall 30-day and 1-year mortality was 2.4% and 9.7%. Myoglobin was elevated in 675 (20%), CK-MB in 421 (12%), and TnI in 517 (15%). Among the 993 patients with renal insufficiency, myoglobin was elevated in 43%, CK-MB in 17%, and TnI in 21%. Independent predictors of 30-day and 1-year mortality were similar and included age ≥65 years, prior MI, and an ischemic electrocardiogram, whereas myoglobin was the strongest multivariate predictor (odds ratio [OR] 2.8, 95% confidence interval [CI] 2.1-3.7), including those with renal insufficiency (OR 2.3, 95% CI 1.6-3.4). Troponin I had borderline predictive value ( P = .08, OR 1.4, 95% CI 0.96-2.0), whereas CK-MB was not predictive in either group. Conclusions Despite the absence of cardiac specificity, an elevated myoglobin strongly predicts mortality, even in patients with renal insufficiency.

Predictive power of ejection fraction and renal failure in patients admitted for chest pain without ST elevation in the troponin era

Ejection fraction (EF) and renal failure (RF) are powerful predictors of mortality in patients with myocardial infarction (MI). There are limited data assessing the predictive value of EF and RF compared with clinical variables in patients without ST elevation using troponin as the diagnostic MI criteria. Consecutive patients admitted from the emergency department underwent serial assessment of cardiac markers, including troponin I. Abnormal EF was defined as < 50%; RF, as creatinine clearance (CrCl) < 60 mL/min. Multivariate analysis was used to compare clinical variables, CrCl, and EF for predicting short- and long-term outcomes. A total of 3074 patients had EF assessed. Mild to moderately reduced EF and CrCl were present in 639 (21%) and 582 (19%) patients, with 403 (13%) and 233 (7.6%) having severe systolic dysfunction and severe RF, respectively. Abnormal EF and RF were both present in 13% of patients (1-year mortality 26%), whereas 52% had both normal EF and CrCl (1-year mortality 3.2%). The presence of either systolic dysfunction or RF increased mortality 3- to 4-fold compared with patients without either. The most important multivariate predictors of 1-year mortality were EF (OR 2.6 [95% CI 1.7-3.8, P < .0001]) and CrCl (OR 2.8 [95% CI 1.8-4.2, P < .0001]). Both RF and EF are strong predictors of cardiac mortality in patients admitted for exclusion of MI. Prediction models that do not include these 2 variables will underestimate risk.

Utility of Troponin I in Patients with Cocaine‐associated Chest Pain

AbstractBaseline electrocardiogram abnormalities and market elevations not associated with myocardial necrosis make accurate diagnosis of myocardial infarction (MI) difficult in patients with cocaine‐associated chest pain. Troponin sampling may offer greater diagnostic utility in these patients. Objective: To assess outcomes based on troponin positivity in patients with cocaine chest pain admitted for exclusion of MI. Methods: Outcomes were examined in patients admitted for possible MI after cocaine use. All patients underwent a rapid rule‐in protocol that included serial sampling of creatine kinase (CK), CK‐MB, and cardiac troponin I (cTnI) over eight hours. Outcomes included CK‐MB MI (CK‐MB ≥ 8 ng/mL with a relative index [(CK‐MB × 100)/total CK] ≥ 4, cardiac death, and significant coronary disease (≥50%). Results: Of the 246 admitted patients, 34 (14%) met CK‐MB criteria for MI and 38 (16%) had cTnI elevations. Angiography was performed in 29 of 38 patients who were cTnI‐positive, with significant disease present in 25 (86%). Three of the four patients without significant disease who had cTnI elevations met CK‐MB criteria for MI, and the other had a peak CK‐MB level of 13 ng/mL. Sensitivities, specificities, and positive and negative likelihood ratios for predicting cardiac death or significant disease were high for both CK‐MB MI and cTnI and were not significantly different. Conclusions: Most patients with cTnI elevations meet CK‐MB criteria for MI, as well as have a high incidence of underlying significant disease. Troponin appears to have an equivalent diagnostic accuracy compared with CK‐MB for diagnosing necrosis in patients with cocaine‐associated chest pain and suspected MI.

Performance of cardiac troponin I in the exclusion of myocardial infarction in patients with advanced renal disease

Performance of cardiac troponin I in the exclusion of myocardial infarction in patients with advanced renal disease

Incidence of high-risk acute coronary syndromes and eligibility for glycoprotein IIb/IIIa inhibitors among patients admitted for possible myocardial ischemia

Objective Recent studies have demonstrated that glycoprotein (GP) IIb/IIIa inhibitors can reduce cardiac events in patients with acute coronary syndromes (ACS). However, little is known about how many patients are actually eligible for treatment. Our purpose was to determine how many patients admitted for possible myocardial infarction (MI) meet GP IIb/IIIa inhibitor treatment criteria. Methods Patients admitted for possible MI who underwent a standard protocol that included serial sampling of total creatine kinase (CK), CK-MB, and troponin I (TnI) were retrospectively assigned to different treatment algorithms on the basis of criteria from GP IIb/IIIa inhibitor trials: an electrocardiogram (ECG) consistent with acute MI or ischemia, and myocardial marker elevations. Elevated CK-MB was considered diagnostic of MI. High-risk ACS was defined as ischemic ECG changes or troponin elevations without CK-MB elevations. Results A total of 2179 patients were admitted for MI exclusion. MI was identified in 304 patients (14.0%) (123 ST-elevation, 49 ischemic ECG, 132 nonischemic ECG). Another 273 patients (12.5%) without CK-MB criteria for MI met high-risk ACS criteria (172 ischemic ECG, 120 TnI elevations). Ischemic ECGs or elevated myocardial markers identified 454 (21%) patients as eligible for treatment. Inclusion of patients with ST elevation increased eligibility to 26.5%. Of the 454 non-ST-elevation ACS patients, 340 (74%) were identified early by the ECG or the initial markers. Conclusions A large proportion of patients admitted for possible MI met criteria for treatment with GP IIb/IIIa inhibitors. The non-ST-elevation ACS group was >3 times larger than the ST-elevation MI group. These findings have important implications for treatment of patients with ACS. (Am Heart J 2002;143:70-5.)