Comparison of cardiac troponin T versus creatine kinase-MB for risk stratification in a chest pain evaluation unit

We evaluated cardiac troponin T (cTnT) and creatine kinase-MB (CK-MB) for risk stratification of chest pain unit (CPU) patients. We studied 383 consecutive patients with chest pain assigned to our CPU by emergency department physicians. At baseline all had normal or nondiagnostic electrocardiograms, no high-risk clinical features, and negative CK/CK-MB. CK-MB and electrocardiograms were taken at 0, 4, 8, and 12 hours and cTnT at 0, 4, and 8 hours. Eight patients (2.1%) were CK-MB positive and 39 (10.2%) were cTnT positive, including all but 1 CK-MB-positive patient. All marker-positive patients were detected by 8 hours. Seven cTnT-positive patients and 1 cTnT-negative patient had myocardial infarction (p <0.0001). cTnT-positive patients were older, less likely to be women or smokers, and more often had diabetes mellitus or known coronary disease (CAD). Seventy-one percent of patients underwent diagnostic testing. cTnT-positive patients more often underwent angiography (46% vs 20%) and underwent stress testing less often (28% vs 57%) than cTnT-negative patients. When performed, their stress tests were more often positive (46% vs 14%) and they more often had angiographically significant lesions (89% vs 49%) and multivessel disease (67% vs 29%). There were no short-term deaths. Long-term mortality was higher in cTnT-positive patients (27% vs 7%, p <0.0001). Thus, cTnT identified more CPU patients with myocardial necrosis and multivessel CAD than CK-MB and a population with high long-term mortality risk. Routine use of cTnT in CPUs could facilitate risk stratification and management.     

Randomized comparison of a strategy of predischarge coronary angiography versus exercise testing in low-risk patients in a chest pain unit: in-hospital and long-term outcomes

OBJECTIVES

This randomized trial compared a strategy of predischarge coronary angiography (CA) with exercise treadmill testing (ETT) in low-risk patients in the chest pain unit (CPU) to reduce repeat emergency department (ED) visits and to identify additional coronary artery disease (CAD).

BACKGROUND

Patients with chest pain and normal electrocardiograms (ECGs) have a low likelihood of CAD and a favorable prognosis, but they often seek repeat evaluations in EDs. Remaining uncertainty regarding their symptoms and diagnosis may cause much of this recidivism.

METHODS

A total of 248 patients with no ischemic ECG changes triaged to a CPU were randomized to CA (n = 123) or ETT (n = 125). All patients had a probability of myocardial infarction ≤7% according to the Goldman algorithm, no biochemical evidence of infarction, the ability to exercise and no previous documented CAD. Patients were followed up for ≥1 year and surveyed regarding their chest pain self-perception and utility of the index evaluation.

RESULTS

Coronary angiography showed disease (≥50% stenosis) in 19% and ETT was positive in 7% of the patients (p = 0.01). During follow-up (374 ± 61 days), patients with a negative CA had fewer returns to the ED (10% vs. 30%, P = 0.0008) and hospital admissions (3% vs. 16%, P = 0.003), compared with patients with a negative/nondiagnostic ETT. The latter group was more likely to consider their pain as cardiac-related (15% vs. 7%), to be unsure about its etiology (38% vs. 26%) and to judge their evaluation as not useful (39% vs. 15%) (p < 0.01 for all comparisons).

CONCLUSIONS

In low-risk patients in the CPU, a strategy of CA detects more CAD than ETT, reduces long-term ED and hospital utilization and yields better patient satisfaction and understanding of their condition.     

Troponin T and quantitative ST-segment depression offer complementary prognostic information in the risk stratification of acute coronary syndrome patients

OBJECTIVES: Our primary objective was to examine the prognostic relationship between baseline quantitative ST-segment depression (ST) and cardiac troponin T (cTnT) elevation. The secondary objectives were to: 1) examine whether ST provided additional insight into therapeutic efficacy of glycoprotein IIb/IIIa therapy similar to that demonstrated by cTnT; and 2) explore whether the time to evaluation impacted on each marker's relative prognostic utility. BACKGROUND: The relationship between the baseline electrocardiogram (ECG) and cTnT measurements in risk-stratifying patients presenting with acute coronary syndromes (ACS) has not been evaluated comprehensively. METHODS: The study population consisted of 959 patients enrolled in the cTnT substudy of the Platelet IIb/IIIa Antagonism for the Reduction of Acute coronary syndrome events in a Global Organization Network (PARAGON)-B trial. Patients were classified as having no ST (n = 387), 1 mm ST (n = 433), and ST > or =2 mm (n = 139). Forty-percent (n = 381) were classified as cTnT-positive based on a definition of > or =0.1 ng/ml. RESULTS: Six-month death/(re)myocardial infarction rates were 8.4% among cTnT-negative patients with no ST and 26.8% among cTnT-positive patients with ST > or =2 mm. On ECGs done after 6 h of symptom onset, ST > or =2 mm was associated with higher risk compared to its presence on ECGs done earlier (odds ratio [OR] 7.3 vs. 2.1). In contrast, the presence of elevated cTnT within 6 h of symptom was associated with a higher risk of adverse events compared with elevations after 6 h (OR 2.4 vs. 1.5). CONCLUSIONS: Quantitative ST and cTnT status are complementary in assessing risk among ACS patients and both should be employed to determine prognosis and assist in medical decision making.     

Prolonged monitoring of troponin T for the detection of anthracycline cardiotoxicity in adults with hematological malignancies

The study was performed to describe the time course of serum cardiac troponin T (cTnT) elevations for the early detection of anthracycline cardiotoxicity. cTnT was analyzed serially in 78 patients with hematological malignancies receiving 142 treatment cycles including various anthracyclines. cTnT positivity was defined as an increase in cTnT >or=0.03 ng/ml and was observed in 12 patients (15%) during 16 treatment cycles (11%). Peak cTnT levels were observed on day +21.5 (median, range: day +6 to day +35) after initiation of anthracycline therapy. cTnT positivity lasted >or=3 days in 63% of cycles and began to occur after a median of two anthracycline doses. Follow-up echocardiography in 28 patients showed a greater decrease in left ventricular ejection fraction (LVEF) in cTnT-positive patients compared to the cTnT-negative group (10% vs 2%, p=0.017). Age, gender, and pretreatment LVEF had no influence on the occurrence of cTnT positivity. Serial measurement of serum cTnT reveals delayed subclinical myocardial damage even after minor anthracycline exposure, may identify patients at risk for subsequent myocardial dysfunction, and suggests prolonged damage to the cardiac myofibrillar system.     

Cardiac troponin T as a prognostic marker in patients with heart failure : a 3-year outcome study

Cardiac troponin T (cTnT), a highly sensitive and specific indicator of myocardial cell death, may be elevated in congestive heart failure (CHF). The aims of this study were to test the hypothesis that decompensated CHF may be associated with an increase in cTnT release and to correlate between cTnT levels and patient outcomes. The authors studied 55 patients aged between 38 and 86 years (30 women and 25 men) who were hospitalized for CHF. Left ventricular ejection fraction (EF) was calculated by using modified Simpson's rule by echocardiography. cTnT levels were assessed. Troponin T >or=0.1 ng/mL was considered as positive. All patients were contacted by phone annually during the next 3 years, and their history of subsequent hospital admissions and current health status were recorded. cTnT was negative in 44 (80%) and positive in 11 (20%) patients. EF was significantly lower and NYHA was higher in cTnT-positive patients. During the 3-year follow-up period, 25 patients died from CHF. The mortality rate was 8/11 (72.7%) among cTnT-positive patients, whereas the mortality rate was 17/44 (38.6%) among cTnT-negative patients. There were significant relationships among positivity of cTnT, NYHA, EF, and mortality rate. Multivariate regression analysis yielded an independent relationship between positivity of cTnT, NYHA classification, and mortality rate. The percent of hospital admissions due to CHF was also higher in patients with cTnT positive (63.6% versus, 27.3%, p <0.05). In conclusion, this study shows that cTnT positivity is an independent risk factor in predicting the long-term mortality and morbidity rate in patients with CHF. Patients with worsening CHF may possibly be identified early on the basis of their elevated serum cTnT levels.     

床边快速肌钙蛋白T测定对急性胸痛患者诊断的价值

目的评价床边快速心肌肌钙蛋白T(cTnT)检测对以急性胸痛症状住院或转科的患者诊断的价值。方法采用床边快速心肌肌钙蛋白T测定仪(CARDIACREADER)测定502例以急性胸痛症状入院或转入心内科的患者入院即刻、6h、12h的cTnT水平,同时测定患者的心肌肌钙蛋白I(cTnI)、肌酸磷酸激酶(CK)及其同功酶(CK-MB)水平。以心电图出现急性心肌梗死(AMI)的动态改变和(或)CK-MB和TnI同时升高诊断为心肌梗死,计算床边快速cTnT诊断急性心肌梗死的特异性、敏感性、阴性预测价值和阳性预测价值。结果502例急性胸痛患者,cTnT阳性160例(31.9%),cTnT阴性323例(64.3%),19例弱阳性。139例cTnT阳性患者发生AMI,7例cTnT阴性的患者发生AMI。床边快速cTnT对以急性胸痛症状住院或转科的患者诊断AMI的特异性为93.8%、敏感性为95.2%、阳性预测价值为86.9%、阴性预测价值为97.8%。结论床边快速肌钙蛋白T测定可以迅速准确地在急性胸痛患者中识别或排除AMI患者,具有重要的诊断价值。     

Cardiac troponin T as a marker for myocardial ischemia in patients seen at the emergency department for acute chest pain.

BACKGROUND: Identification of patients with acute chest pain at high risk for cardiovascular complications is a common and difficult challenge for clinicians and must be based initially on data from the history, physical examination, electrocardiogram, and chest radiograph. Some data suggest that elevations in cardiac troponin T (cTnT) may be useful for detection of less severe degrees of myocardial injury that may occur in some patients with unstable angina. Therefore we designed a prospective follow-up study to assess the diagnostic performance and prognostic value of cTnT in a population of patients presenting to the emergency department with acute chest pain. METHODS: The patient population included all 1477 admitted patients aged 30 years or more who presented to the emergency department of an urban teaching hospital from October 1992, through February 1994, with a chief symptom of acute chest pain not explained by trauma or chest radiograph abnormalities. The 1303 patients (88%) who had 2 or more measurements of cTnT during the first 24 hours after presentation comprised the final study population. Sensitivity, specificity, positive predictive value, negative predictive value, and receiver operator characteristics curve (ROC) were determined for cTnT and creatine kinase-MB (CK-MB) (measured using activity and mass assays) data from the first 24 hours after admission for the outcomes of acute myocardial infarction (AMI) and major cardiac events during the first 72 hours of hospitalization. RESULTS: The sensitivity and specificity of cTnT (threshold of 0.1 ng/mL) for detecting AMI during the first 24 hours after presentation were 99% and 86%, respectively. The CK-MB activity and mass assays had diagnostic performance for detecting AMI similar to cTnT. Among patients who did not meet study criteria for AMI, cTnT was elevated during the first 24 hours in 31% of patients who had major complications, compared with a 17% rate for the CK-MB activity assay and a 3% rate for the CK-MB mass assay. In these patients, the cTnT assay had superior diagnostic performance compared with the CK-MB mass assay as a marker for cardiac complications as assessed with ROC analysis (P <.0004). CONCLUSIONS: In a heterogeneous population of patients seen in the emergency department with acute chest pain, cTnT was similar to CK-MB (activity and mass assays) for detection of AMI and superior to the CK-MB mass assay as a marker for major cardiac events early in the hospital course among those who were ruled out for an AMI. Further study is required to determine how this assay can be used to provide more appropriate, cost-effective care.     

3种心肌标志物在急性心肌梗死早期诊断中的价值

目的探讨肌钙蛋白T(cTnT)、肌酸激酶同工酶(CK-MB)、肌红蛋白(MYO)3种心肌标志物检测对急性心肌梗死(AMI)早期诊断的价值。方法用胶体金免疫层析法测定120例心肌梗死患者的3种血清心肌标志物的浓度,比较其对AMI诊断的性能价值。结果 120例心肌梗死患者在胸痛发作6h内检测cTnT、CK-MB和MYO的敏感率分别是81.4%、60.5%和97.7%,以MYO浓度升高最快,出现最早;发病6h～24h内检测cTnT、CK-MB和MYO的敏感率分别是99.0%、79.4%和79.0%,以cTnT浓度最稳定;在发病8h内检测cTnT、CK-MB和MYO的敏感性分别为91.0%、70.0%和99.0%,特异性分别为100%、91.0%和79.0%;漏诊率分别是9.0%、30.0%和1.0%;误诊率分别是0、9.0%和21.0%。结论 cTnT在AMI早期诊断中具有较高的敏感性、特异性和准确性,是早期诊断AMI的"金指标",MYO可作为AMI的过筛,三者结合可提高早期AMI的诊断率,并有助于病情的分析。     

C-Reactive Protein Is a Potent Predictor of Mortality Independently of and in Combination With Troponin T in Acute Coronary Syndromes: A TIMI 11A Substudy

Objectives. We evaluated C-reactive protein (CRP) alone and in conjunction with a rapid qualitative assay for cardiac-specific troponin T (cTnT) for predicting 14-day mortality in patients with unstable angina or non-Q wave myocardial infarction (NQMI).

Background. Elevated CRP has been found to correlate with higher risk for cardiac events in patients with coronary disease.

Methods. At enrollment into the Thrombolysis in Myocardial Infarction (TIMI) 11A trial, a dose-ranging trial of enoxaparin for unstable angina and NQMI, serum was obtained for CRP measurement and rapid cTnT assay.

Results. Quantitative CRP and rapid cTnT assays were performed in all patients. CRP was higher among patients who died than in survivors (7.2 vs. 1.3 mg/dl, p = 0.0038). The probability of a positive rapid cTnT assay rose with increasing CRP concentration (p < 0.0001). Among patients with a negative rapid cTnT assay, the mortality rate was higher among patients with CRP ≥1.55 mg/dl (5.80% vs. 0.36%, p = 0.006). Patients with both an early positive rapid cTnT assay (≤10 min until assay positive) and CRP ≥1.55 mg/dl had the highest mortality, followed by those with either CRP ≥1.55 mg/dl or an early positive rapid cTnT assay, whereas patients with both a negative rapid cTnT assay and CRP <1.55 mg/dl were at very low risk (9.10% vs. 4.65% vs. 0.36%, p = 0.0003).

Conclusions. Elevated CRP at presentation in patients with unstable angina or NQMI is correlated with increased 14-day mortality, even in patients with a negative rapid cTnT assay. Quantitative CRP and a rapid cTnT assay provide complementary information for stratifying patients with regard to mortality risk.     

Myocardial protective effects of nicorandil during percutaneous coronary intervention in patients with unstable angina.

BACKGROUND: The purpose of the study was to prospectively evaluate the protective effect of nicorandil during percutaneous coronary intervention (PCI) in patients with unstable angina (UAP). METHODS AND RESULTS: Two hundred patients (61+/-10 year-old, male 143) diagnosed with UAP at an emergency medical center were randomly assigned to 2 groups: intravenous isosorbide dinitrate, Group I (n=100), or intravenous nicorandil, Group II (n=100). PCI was performed 12-48 h after infusion of each agent. Serum concentrations of creatine kinase-MB (CK-MB), cardiac troponin T (cTnT), and I (cTnI) were measured before and 6, 12, 24 h after PCI. Patients with non-coronary chest pain, requiring emergency coronary angiogram, temporary pacemaker or glycoprotein IIb/IIIa receptor blocker were excluded. PCI was successfully performed in 96 patients (Group I=54, 61.7+/-8.2 years, 32 males; Group II=42, 60.4+/-11.7 years, 27 males). No significant differences in clinical or coronary angiographic characteristics were observed between the 2 groups. The concentration of CK-MB was elevated in 9 patients (17%) of Group I and 6 (14%) of Group II, cTnT in 16 (30%), 6 (14%) and cTnI in 25 (46%), 9 (21%) after PCI. Elevation of any troponin was less frequent in Group II [28/54 (52%) vs 10/42 (24%) patients, p=0.01]. Major adverse coronary events during the 6-month clinical follow-up occurred in 9 (17%) of Group I and 5 patients of Group II (12%, p=NS). Follow-up echocardiography revealed lower left ventricular ejection fraction in Group I than in Group II (65.4+/-7.2% vs 71.0+/-6.7%, p=0.03). CONCLUSION: Nicorandil has a myocardial protective effect during PCI in patients with UAP.     

Prognostic significance of ST segment depression in lateral leads I, aVL, V5 and V6 on the admission electrocardiogram in patients with a first acute myocardial infarction without ST segment elevation

OBJECTIVES

We sought to investigate the short-term prognostic value of the admission electrocardiogram (ECG) in patients with a first acute myocardial infarction (MI) without ST segment elevation.

BACKGROUND

ST segment depression on hospital admission predicts a worse outcome in patients with a first acute MI, but the prognostic information provided by the location of ST segment depression remains unclear.

METHODS

In 432 patients with a first acute MI without Q waves or ≥0.1 mV of ST segment elevation, we evaluated the ability of the initial ECG to predict in-hospital death.

RESULTS

The presence, magnitude and extent of ST segment depression were associated with an increased mortality, but the only electrocardiographic variable that was significant in predicting death after adjusting for baseline predictors was ST segment depression in two or more lateral (I, aVL, V₅, or V₆) leads (odds ratio 3.5, 95% confidence interval 1.2 to 10.6). Patients with lateral ST segment depression (n = 91, 21%) had higher rates of death (14.3% vs. 2.6%, p < 0.001), severe heart failure (14.3% vs. 4.1%, p < 0.001) and angina with electrocardiographic changes (20.0% vs. 11.6%, p = 0.04) than did the remaining patients, even though they had similar peak creatine kinase, MB fraction levels (129 ± 96 vs. 122 ± 92 IU/liter, p = NS). In contrast, ST segment depression not involving the lateral leads did not predict a poor outcome. Among patients who were catheterized, those with lateral ST segment depression had a lower left ventricular ejection fraction (57 ± 12% vs. 66 ± 13%, p = 0.001) and more frequent left main coronary artery or three-vessel disease than did the remaining patients (60% vs. 22%, p < 0.001).

CONCLUSIONS

In patients with a first non–ST segment elevation acute MI, ST segment depression in the lateral leads on hospital admission predicts a poor in-hospital outcome.     

Isolated elevation in troponin T after percutaneous coronary intervention is associated with higher long-term mortality.

OBJECTIVES: The aim of this study was to evaluate whether, in patients with normal post-procedure CK-MB, an isolated elevation in cardiac troponin T (cTnT) predicts long-term survival. BACKGROUND: Cardiac troponin T is a sensitive and specific marker of myonecrosis. There is little known about the incidence and prognostic significance of an isolated elevation of cTnT without a rise in creatine kinase (CK)-MB following PCI. METHODS: We evaluated the outcomes of 1,949 patients from the Mayo Clinic registry who had normal pre-procedure cTnT and CK-MB, required nonemergency percutaneous coronary intervention (PCI), and had normal CK-MB after the procedure. RESULTS: An elevation in cTnT (cTnT+) was observed in 383 patients (19.6%) (median 0.04 ng/ml, interquartile range 0.03 to 0.06 ng/ml). The TnT+ status was associated with adverse clinical and angiographic characteristics, and multivessel PCI. Over the median follow-up duration of 26 months, mortality (p < 0.001) and the combined rate of death and myocardial infarction (p = 0.004) were significantly higher in cTnT+ patients. Estimated 3-year survival for those with and without cTnT elevation was 86.9% and 93.2%, respectively. By multivariate analysis, an elevation in cTnT after PCI was an independent predictor of increased long-term mortality. A doubling in the post-PCI cTnT was associated with a partial hazard ratio of 1.20 (95% confidence interval 1.02 to 1.40; p = 0.023). CONCLUSIONS: An isolated minor elevation in cTnT after PCI provides long-term prognostic information regarding mortality and myocardial infarction.     

Chest pain early after percutaneous coronary intervention: incidence and relation to ECG changes, cardiac enzymes and follow-up events

To investigate the incidence of chest pain early after percutaneous coronary interventions and its correlation with ECG changes, cardiac enzymes, clinical and procedural variables and follow-up events, we prospectively studied 199 patients (84% male; mean age, 60.1 +/- 9.4 years) after primary successful percutaneous coronary interventions (21% PTCA; 79% additional stent implantation). During the first 16 hours following the intervention, the occurrence of chest pain was noted, ECGs were recorded and serial measurements of cardiac enzymes were performed. Seventy-six patients (38%) with elevated enzyme levels at time 0 were excluded. A clinical follow-up was obtained at 6 months. Forty patients (32.5%) experienced chest pain; new ECG changes were detected in 3 (2.5%). The mean levels of all enzymes were significantly higher in patients with chest pain 16 hours after the intervention. In patients with chest pain versus those without, CK-MB mass and troponin I levels higher than twice the upper normal limit were seen in 43.6% versus 11.0% (p < 0.0001) and 45.0% versus 17.3% (p < 0.002), respectively. Elevated troponin I (< 0.004) and CK-MB mass (< 0.04) as well as presumed ischemic chest pain (< 0.03) could be identified as risk factors for recurrent chest pain during follow-up. In conclusion, chest pain was common early after percutaneous coronary interventions and correlated with elevated cardiac enzymes, suggesting peri-interventional myocardial necrosis. Elevated levels of CK-MB mass and troponin I, as well as presumed ischemic chest pain, were associated with recurrent chest pain during follow-up.     

Electrocardiogram abnormalities predict angiographic coronary artery disease in women with chest pain: results from the NHLBI WISE Study

BACKGROUND AND HYPOTHESIS: Noninvasive risk stratification for coronary artery disease (CAD) isless accurate in women than in men. Based on recent reports that gender-specific exercise electrocardiogram (ECG) parameters predict CAD, we evaluated the independent predictive value of the resting ECG for angiographic CAD in women with chest pain. METHODS: Women (n = 850, mean age 58 years) with chest pain in the NHLBI Women's Ischemia Syndrome Evaluation (WISE) underwent 12-lead ECG testing and quantitative coronary angiography. RESULTS: Significant angiographic CAD (> or = 50% stenosis in > or = 1 coronary) was present in 39% of women. Q waves in < or = 2 contiguous ECG leads were present in 107 women (13%), including 49 of 657 (7%) without history of infarction. Among 585 women without prior infarction orrevascularization, 48% of those with Q waves in contiguous leads versus 26% of others, had significant CAD (p = 0.003; odds ratio [OR] = 2.5, 95% confidence interval [CI] = 1.3-4.8). Women with Q waves in < or = 2 inferior ECG leads were particularly likely to have CAD (63 vs. 26% of others, p < 0.001; OR = 4.6,95% CI = 2.0-10.8). Other ECG findings predictive of CAD were any ST-T abnormality (OR = 1.9,95% CI = 1.3-2.8) and T-wave inversion (OR = 2.4, 95% CI = 1.3-4.2). In risk-adjusted analysis, inferior Q waves and T-wave inversion independently predicted significant CAD. When considered together with radionuclide perfusion test results, T-wave inversion on resting ECG added significant independent predictive value (OR = 2.8, 95% CI = 1.1-7.2, p = 0.03). CONCLUSIONS: Selected resting ECG parameters independently predict angiographic CAD in women with chest pain, including women who have also undergone radionuclide stress testing. Prospective studies should consider resting ECG parameters in diagnostic algorithms for CAD in women.     

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.     

Proton pump inhibitors for patients with coronary artery disease associated with reduced chest pain, emergency department visits, and hospitalizations

BACKGROUND: Patients with coronary artery disease (CAD) presenting to an emergency department (ED) with chest pain are likely to undergo hospitalization as clinicians attempt to elucidate the etiology. HYPOTHESIS: We hypothesized that proton pump inhibitor (PPI) therapy is associated with reduced chest pain events and evaluations in patients with CAD. METHODS: A patient population from a veterans medical center with documented CAD was identified retrospectively, and chest pain episodes, ED visits, and hospitalizations for chest pain were prospectively followed over 2 years. Comparison of patient outcomes between PPI (+PPI) and nonuse of PPI therapy (-PPI) was determined. RESULTS: Of 415 male patients, average age 73.4 years, 23% utilized a PPI and 77% did not. Proton pump inhibitor therapy was associated with reduced chest pain episodes (11.8 vs. 26.2%, p = 0.002), ED visits (12.3 vs. 24.3%, p = 0.044), and hospitalizations (12.8 vs. 23.9%, p = 0.086). Relative reductions were 55, 49, and 46%, respectively, after 2 years. Numbers of adverse events were also decreased in the +PPI group of patients: 70% fewer occurrences of chest pain (p = 0.002, relative risk [RR] = 3.3), 55% fewer ED visits (p = 0.049, RR = 2.2), and 53% fewer hospitalizations (p = 0.064, RR = 2.1). By multivariate analysis, PPI therapy independently predicted reduced prevalence of patients experiencing chest pain, ED visits, or hospitalizations (odds ratio [OR] = 0.09 [0.04-0.21]; 0.15 [0.06-0.40]; 0.14 [0.05-0.40]; all p < 0.001). CONCLUSIONS: Proton pump inhibitor therapy for male patients with CAD from a veterans medical center was associated with reduced prevalence of chest pain, ED visits, and hospitalizations for chest pain and reduced incidence of these events.     

Immediate exercise testing of low risk patients with known coronary artery disease presenting to the emergency department with chest pain

OBJECTIVES

The purpose of this study was to demonstrate the safety and utility of immediate exercise treadmill testing (IETT) of low risk patients presenting to the emergency department with known coronary artery disease (CAD).

BACKGROUND

More than 70% of the two million patients admitted to U.S. hospitals annually for suspected acute myocardial infarction (AMI) are found not to have had a cardiac event. We have previously demonstrated the safety and efficacy of IETT of selected low risk patients without known CAD presenting to the emergency department with chest pain. This study extends this approach to selected patients with a history of CAD.

METHODS

One hundred patients evaluated by the chest pain emergency room to rule out AMI underwent IETT using a modified Bruce protocol upon admission to the hospital (median time <1 h).

RESULTS

Twenty-three patients (23%) had positive exercise electrocardiograms (ExECGs); an uncomplicated non–Q wave AMI was diagnosed in two patients. Thirty-eight patients (38%) had negative ExECGs and 39 patients (39%) had nondiagnostic ExECGs. Of these 100 patients, 64 were discharged immediately after IETT, 19 were discharged in less than 24 h after negative serial cardiac enzymes and stable electrocardiograms and 17 were discharged after further evaluation and treatment. There were no complications from exercise testing and no late deaths or AMI during six-month follow-up.

CONCLUSIONS

Immediate exercise treadmill testing of low risk patients with chest pain and known CAD is effective in further stratifying this group into patients who can be safely discharged and those who require hospital admission.     

The pacing stress test: a reexamination of the relation between coronary artery disease and pacing-induced electrocardiographic changes

Electrocardiographic (ECG) changes during graded pacing-induced tachycardia have been considered unreliable as a test for the presence of coronary artery disease (CAD) because of poor sensitivity and specificity. As a result, atrial pacing has not been widely used as an alternative to exercise testing. However, the limited value of the pacing stress test may be related to technical aspects, such as the duration of pacing and ECG monitoring. To study this problem, 22 patients undergoing coronary cineangiography underwent standard exercise stress testing and graded tachycardia induced by atrial pacing. A 12-lead ECG recorder was used for both tests. Pacing tachycardia was terminated when 85% of maximal predicted heart rate had been achieved or when significant ischemic chest pain accompanied by diagnostic ECG changes occurred. The ECG was considered positive if at least 1 mm of horizontal or downsloping ST-segment depression was present. Six patients with normal or minimally diseased coronary arteries were compared to 16 patients with significant CAD. Of the patients without significant CAD, 5 (83%) had a negative electrocardiogram during both exercise and pacing. Of 16 patients with CAD, the electrocardiogram was positive for ischemia in 10 patients (63%) during exercise, in 15 (94%) during atrial pacing and in 12 (80%) after pacing. When the presence or absence of ECG changes was compared between the exercise and the pacing tests, there was a concordance of 90% (Fisher p less than 0.0015). Two patients without significant CAD (33%) had chest pain during both exercise and pacing. Among patients with CAD, 7 (44%) had chest pain during exercise and 8 (50%) had chest pain during atrial pacing.(ABSTRACT TRUNCATED AT 250 WORDS)     

The significance of stress-induced ST segment depression in patients with inferior Q wave myocardial infarction

OBJECTIVES

This study was conducted to evaluate the relationship between ST segment depression (STD) during dobutamine stress tests in different electrocardiogram (ECG) leads and myocardial ischemia assessed by simultaneous single photon emission computed tomography (SPECT) imaging in patients with inferior Q wave myocardial infarction.

BACKGROUND

STD is a standard electrocardiographic sign of myocardial ischemia. Although STD may represent reciprocal changes in patients with previous myocardial infarction, studies of reciprocal changes during stress tests are scarce.

METHODS

Dobutamine (up to 40 μg/kg/min) stress and rest myocardial perfusion scintigraphy using technetium SPECT imaging was performed in 125 patients >3 months after Q wave inferior myocardial infarction. The location of STD at the ECG was defined as anterior (V_1–4), high lateral (I, aVL) and lateral (V_5,6). Ischemia was defined as reversible perfusion abnormalities.

RESULTS

STD occurred in the high lateral leads in 20 patients, in the anterior leads in 12 patients and in the lateral leads in 2 patients. ST segment elevation occurred in 25 patients in the inferior leads. High lateral STD was associated with inferior ST elevation in 16 patients (80%). There was a significant inverse linear correlation between the magnitude of ST segment shift from rest to peak stress in the inferior and the high lateral leads (r = −0.8, p < 0.0005), whereas no significant correlation was found between ST segment shift in the inferior and the anterior leads (r = −0.1, p = NS) or between the inferior and the lateral leads (r = 0.15, p = NS). Ischemia was detected in 45% of patients with and in 42% of patients without high lateral STD (p = NS). Patients with high lateral STD had a higher prevalence of fixed perfusion defects in the inferior wall (100% vs. 70%) and in the posterolateral wall (55% vs. 29%) compared with other patients (both p < 0.05). Ischemia was more prevalent in patients with anterior STD than without (75% vs. 39%, p < 0.05).

CONCLUSIONS

In patients with inferior Q wave myocardial infarction, stress-induced STD in high lateral leads should be recognized as a reciprocal change for ST elevation in the inferior leads, and therefore, should be interpreted with the consideration of the significance of ST elevation if present, rather than being indicative of myocardial ischemia on its own. The STD found in the anterior leads appears to be a sign of myocardial ischemia. These findings should be considered in the definition of a positive ECG stress test and in establishing the criteria for the termination of stress test.     

Usefulness of the total cholesterol to high-density lipoprotein cholesterol ratio in predicting angiographic coronary artery disease in women

To investigate the relation between lipids and angiographic coronary artery disease (CAD) in women, fasting lipid profiles were obtained on 108 women undergoing coronary angiography (group I). CAD, defined as ≥25% luminal diameter narrowing in a major coronary artery, was present in 57 (53%). Neither serum total cholesterol nor triglyceride levels correlated with the presence of CAD. Mean total/high-density lipoprotein (HDL) cholesterol ratio was higher among women with than without CAD (5.5 ± 0.3 vs 4.2 ± 0.2, p < 0.0001). Multiple regression analyses identified a higher total/HDL cholesterol ratio as the variable most predictive of the presence (p < 0.001), extent (number of narrowed arteries) (p < 0.0001), and severity (% maximum stenosis) (p < 0.001) of CAD. Age and lack of estrogen use were also independently associated with the presence of CAD, age and lowdensity lipoprotein cholesterol level were additional indicators of extent, and age was the only other discriminator of severity of CAD.

In 56 women with total cholesterol <200 mg/dl (group II), mean total/HDL cholesterol ratio was higher in women with (n = 24) than without CAD (4.3 ± 0.2 vs 3.5 ± 0.2, P = 0.01). Higher total/HDL cholesterol ratio was the variable most predictive of the presence of CAD (p = 0.01), and the tone variable associated with severity (p < 0.001) after adjustment for other risk factors. Age was independently associated with presence and extent, and hypertension was also independently related to extent. Thus, among these women, total/HDL cholesterol ratio is the best predictor of the presence, severity and extent of CAD in general, and is the best predictor of presence, and severity in patients with total cholesterol <200 mg/dl.