A practical approach with outcome for the prognostic assessment of non-ST-segment elevation chest pain and normal troponin

Clinical Evaluation Versus Undetectable High-Sensitivity Troponin for Assessment of Patients With Acute Chest Pain

Decision-making in acute chest pain remains challenging despite normal (below ninety-ninth percentile) high-sensitivity troponin (hs-cTn). Some studies suggest that undetectable hs-cTn, far below the ninety-ninth percentile, might rule out acute coronary syndrome. We investigated clinical data in comparison to undetectable hs-cTnT. The study comprised 682 patients (November 2010 to September 2011) presenting at the emergency department with chest pain and normal hs-cTnT (<14 ng/l). The main end point was major adverse cardiac events (MACE: death, myocardial infarction, readmission for unstable angina, or revascularization) at a 4-year median follow-up; secondary end point was 30-day MACE. A clinical score was built by assigning points according to hazard ratios of the independent predictive variables: 1 point (male and effort-related pain) and 2 points (recurrent pain and prior ischemic heart disease). The negative predictive values of the clinical score and undetectable hs-cTnT (<5 ng/l), were tested. A total of 72 (10.6%) patients suffered long-term MACE. The C-statistics of the clinical score for long-term (0.75) and 30-day (0.88) MACE were higher than with the TIMI(Thrombolysis In Myocardial Infarction) risk (0.68, 0.77) or GRACE(Global Registry of Acute Coronary Events) (0.50, 0.47) scores. Likewise, the negative predictive values of score = 0 (97.5%, 100%) and ≤1 point (95.9%, 100%) were higher than using undetectable hs-cTnT (91.9%, 98.1%). Both clinical scores of 0 and ≤1 better classified patients at risk of MACE (p = 0.0001, log-rank test) than hs-cTnT <5 ng/l (p = 0.06). In conclusion, clinical data can guide decision-making and perform at least equally well as undetectable hs-cTnT, in patients presenting at the emergency department with chest pain and normal hs-cTnT.

Heart-type fatty acid-binding protein predicts long-term mortality and re-infarction in consecutive patients with suspected acute coronary syndrome who are troponin-negative

OBJECTIVES

The purpose of this study was to establish the prognostic value of measuring heart fatty acid-binding protein (H-FABP) in patients with suspected acute coronary syndrome (ACS) (in particular, low- to intermediate-risk patients), in addition to troponin measured with the latest third-generation troponin assay.

BACKGROUND

We have previously shown that H-FABP is a useful prognostic marker in patients with proven ACS.

METHODS

Patients (n = 1,080) consecutively admitted to the hospital with suspected ACS were recruited over 46 weeks. Siemens Advia Ultra-TnI (Siemens Healthcare Diagnostics, Newbury, United Kingdom) and Randox Evidence H-FABP (Randox Laboratories, Ltd., Co., Antrim, United Kingdom) were analyzed on samples collected 12 to 24 h from symptom onset. After exclusion of patients with ST-segment elevation and new left bundle branch block, 955 patients were included in the analysis.

RESULTS

The primary outcome measure of death or readmission with myocardial infarction after a minimum follow-up period of 12 months (median 18 months) occurred in 96 of 955 patients (10.1%). The H-FABP concentration was an independent predictor of death or myocardial infarction, after multivariate adjustment. Patients with H-FABP concentrations >6.48 microg/l had significantly increased risk of adverse events (adjusted hazard ratio: 2.62, 95% confidence interval: 1.30 to 5.28, p = 0.007). Among troponin-negative patients (which constituted 79.2% of the cohort), the aforementioned cutoff of 6.48 microg/l identified patients at very high risk for adverse outcomes independent of patient age and serum creatinine.

CONCLUSIONS

We have demonstrated that the prognostic value of elevated H-FABP is additive to troponin in low- and intermediate-risk patients with suspected ACS. Other studies suggest that our observations reflect the value of H-FABP as a marker of myocardial ischemia, even in the absence of frank necrosis.

Randomized comparison between clinical evaluation plus N-terminal pro-B-type natriuretic peptide versus exercise testing for decision making in acute chest pain of uncertain origin

BACKGROUND

Exercise testing constitutes the usual tool for decision making in chest pain units. This policy implies logistical constrains. Our aim was to evaluate a new strategy, combining a clinical risk score and N-terminal pro-B-type natriuretic peptide (NT-proBNP), in patients presenting to the emergency department with chest pain, without ischemic electrocardiogram changes or troponin elevation.

METHODS

A total of 320 patients were randomized to either usual management, involving exercise testing, or a new strategy combining a clinical risk score and NT-proBNP without exercise testing. In the usual management, discharge decision was guided by the result of exercise test. In the new strategy, those patients with low clinical risk score and NT-proBNP were directly discharged. The primary outcome was hospitalization at the index episode. Secondary outcomes were cardiac events at 1 year.

RESULTS

A total of 110 patients (69%) were hospitalized using usual management in comparison with 90 (56%) in the new strategy (P = .03). There were no differences in death or myocardial infarction (n = 11, 6.9% vs n = 6, 3.8%, P = .3) or cardiac events (n = 38, 24% vs n = 28, 18%, P = .2). Revascularizations at the index episode were more frequent under usual management (18% vs 8%, P = .01), although the new strategy was associated with higher rate of planned postdischarge revascularizations (0.6% vs 5%, P = .04).

CONCLUSIONS

A strategy combining clinical history and NT-proBNP is simpler and reduced initial emergency hospitalizations in patients with chest pain, in comparison with the usual strategy involving exercise testing. Larger studies to assess its impact on long-term hard end points are needed.

Efficacy of coronary revascularization in patients with acute chest pain managed in a chest pain unit

OBJECTIVE

To investigate the safety of discharge of patients deemed at low risk of cardiac events after evaluation in a chest pain unit and to determine the prognostic effect of revascularization of patients deemed at high risk.

PATIENTS AND METHODS

The study population consisted of 1088 patients presenting at the emergency department from January 15, 2001, to September 1, 2006, with chest pain but without ischemia on electrocardiography or troponin elevation. Patients were managed by a chest pain unit protocol that included early exercise testing. Three groups of patients were distinguished: (1) those discharged after exercise testing (424 [39%]); (2) those in whom unstable angina was ruled out after in-hospital evaluation (208 [19%]); and (3) those in whom unstable angina was confirmed or not ruled out (456 [42%]). Of the 456 patients in group 3, 183 (40%) were revascularized at the index episode. The primary end point was the occurrence of myocardial infarction or death within 1 year. Adjustments were made for patient characteristics and a propensity score for revascularization (c statistic [0.83]).

RESULTS

Groups 1 and 2 showed lower rates of the primary end point than group 3 (group 1: 7 [1.7%]; group 2: 1 [0.5%]; group 3: 62 [13.6%]; P=.001). In group 3, revascularization at the index episode did not reduce the primary end point in the univariate (22 [12%] vs 29 [11%]; P=.80) and multivariate (hazard ratio, 1.4; 95% confidence interval, 0.7-2.5; P=.40) analyses. In-hospital revascularization decreased the need for postdischarge revascularization (hazard ratio, 0.3; 95% confidence interval, 0.1-0.7; P=.01).

CONCLUSION

Chest pain unit protocols are associated with safe patient discharge. Although early revascularizations may decrease the need for postdischarge revascularizations, they may not improve 1-year outcomes by reducing the number of myocardial infarctions or deaths.

Relationship between low lymphocyte count and major cardiac events in patients with acute chest pain, a non-diagnostic electrocardiogram and normal troponin levels

OBJECTIVE

Risk stratification of patients with acute chest pain, non-diagnostic electrocardiogram and normal troponin (ACPneg) remains a challenge, partly because no standardized set of biomarkers with prognostic ability has been identified in this population. Lymphopenia has been associated with atherosclerosis progression and adverse outcomes in cardiovascular diseases; although its prognostic value in ACPneg is unknown. We sought to determine the relationship between the lymphocyte count obtained in the Emergency Department (ED) and the risk of the long-term all-cause mortality or myocardial infarction (MI) in patients with ACPneg.

METHODS

We analyzed 1030 consecutive patients admitted with ACPneg in our institution. Lymphocyte count was determined in the ED as a part of a routine diagnostic workup to rule out an acute coronary syndrome. Patients with inflammatory, infectious diseases, or active malignancy were excluded (final sample=975). The independent association between lymphocyte count and the composite endpoint (death/MI) was assessed by survival analysis for competing risk events (revascularization procedures).

RESULTS

During a median follow-up of 36 months, 139 (14.3%) patients achieved the combined endpoint, with rates increasing monotonically across lymphocyte quartiles (6.2%, 10%, 20.6% and 24.1% for Q4, Q3, Q2 and Q1 (p<0.001), respectively). In a multivariable analysis, patients in lymphocytes' Q1 and Q2 as compared with those in Q4 had an increased risk for the combined endpoint: HR=2.45 (CI 95% 1.25-4.79, p=0.008) and HR=2.56 (CI 95% 1.30-5.07, p=0.007), respectively.

CONCLUSION

In patients with ACPneg, low lymphocytes count was associated with an increased risk for developing the combined endpoint of death or MI.

Resting magnetocardiography predicts 3-year mortality in patients presenting with acute chest pain without ST segment elevation

OBJECTIVE

Magnetocardiography (MCG) as a noninvasive, noncontact and risk-free diagnostic method predicts ischemic coronary artery disease (CAD) in patients with acute chest pain at admission with high accuracy. However, it remains unclear whether MCG findings can add prognostic information.

METHOD

A cohort of 402 consecutive patients presenting at the intensive care unit (ICU) with acute chest pain without ST segment elevation (NSTEMI) were included in a prospective registry. In order to prove the prognostic value of MCG a head-to-head comparison of the admission MCG, ECG, TnI, and ECHO tests was made.

RESULTS

In 43 patients (10.7%) the MCG could not be analyzed due to insufficient signal-to-noise ratio. Complete follow-up over a period of up to 3 years was obtained in 355 out of the 359 patients (98.9%). Age at admission was 67.2 +/- 10.3 years, 59.7% males. In the group of patients with an abnormal MCG at admission, 43 out of 249 patients (17.3%) died in the follow-up period, while in the group of patients with a normal MCG at admission only 4 out of 106 patients died (3.77%). The relative risk was 4.58 (95% confidence intervals: 1.68-12.42). A multivariate regression analysis revealed the highest mortality risk for patients with diabetes mellitus and an abnormal MCG at admission (RR = 18.0; 95% CI: 2.49-133.3).

CONCLUSION

Resting MCG at hospital admission predicts 3-year mortality in patients presenting with acute chest pain without ST segment elevation in the ECG. MCG seems to be valuable in identifying chest pain patients at highest risk.

Limitations of clinical history for evaluation of patients with acute chest pain, non-diagnostic electrocardiogram, and normal troponin

Decision making and risk stratification for patients with acute chest pain, nondiagnostic electrocardiogram results, and normal troponin levels are challenging. The aim of this study was to optimize the clinical history for the evaluation of these patients. A total of 1,011 patients presenting to an emergency department were included. The following data were collected: clinical presentation (pain characteristics and number of pain episodes), coronary risk factors, previous ischemic heart disease, and extracardiac vascular disease (peripheral artery disease, stroke, or creatinine >1.4 mg/dl). Two different predictive models were calculated according to the end points: model 1 for 1-year major events (death or myocardial infarction) and model 2 for 30-day cardiac events (major events or revascularization). For 1-year major events, model 1 showed optimal discrimination capacity (C statistic = 0.80), which was significantly better than that of model 2 (C statistic = 0.77, p = 0.04). With respect to 30-day cardiac events, however, discrimination was lower in the 2 models, without differences between them (C statistic = 0.74 vs 0.75, p = NS). Using model 1, a large low-risk subgroup with <3 predictive variables could be defined, including 442 patients (44% of the total population) with a 1.4% rate of 1-year major events; however, the incidence of 30-day cardiac events (8%) was not negligible, mainly because of revascularizations. In conclusion, in patients with acute chest pain of uncertain coronary origin, clinical predictive models afford good risk stratification for long-term major events. Short-term outcomes, including revascularization, however, are not predicted as well. Therefore, ancillary tools, such as noninvasive stress tests, should be implemented for decision making at initial hospitalization or discharge.