Clinically recognized cardiac dysfunction: an independent determinant of mortality among critically ill patients. Is there a role for serial measurement of cardiac troponin I?

Serial measurement of cardiac troponin I in hospitalised dogs with canine parvoviral enteritis: Association with outcome and canine pancreas-specific lipase concentration

The aim of this study was to serially evaluate serum cardiac troponin I (cTnI) concentrations in dogs with parvoviral enteritis (CPVE), and investigate the association with outcome and serum pancreas-specific lipase (Spec cPL) concentrations. Dogs with CPVE that were hospitalised for at least 5 days were included. cTnI and Spec cPL concentrations were measured on days 1, 3 and 5 of hospitalisation. Twenty-nine dogs (20 survivors, 9 non-survivors) were included. Spec cPL was indicative of pancreatitis (>400 μg/L) on at least one day in 10/29 (34.5%) dogs. Serum median (range) cTnI concentration was higher (P = 0.021) in non-survivors on day 5 [0.032 (0.001-0.395) ng/mL] compared to day 1 [0.012 (0.003-0.196) ng/mL]. Non-survivors had higher (P = 0.014) cTnI concentrations on day 5 [0.032 (0.001-0.395) ng/mL] compared to survivors [0.001 (0.001-0.042) ng/mL], but not at admission or on day 3 (P > 0.05). Serum cTnI concentrations were not significantly different (P = 0.465) between the three Spec cPL groups [group 1 (Spec cPL ≤ 200 μg/L): 0.007 (0.001-0.527) ng/mL; group 2 (Spec cPL: 201-399 μg/L): 0.0045 (0.001-0.196) ng/mL; group 3 (Spec cPL ≥ 400 μg/L): 0.011 (0.001-0.278) ng/mL]. cTnI and Spec cPL concentrations were not significantly correlated (rho = -0.043, P = 0.703). Serial measurement of cTnI had prognostic value in the examined cohort. However, cTnI was not correlated with spec cPL.

Prognostic Value of Cardiac Troponin I and T on Admission in Mortality of Multiple Trauma Patients Admitted to the Emergency Department: a Prospective Follow-up Study

Introduction:

The relationship between increased levels of cardiac troponins and morbidity and mortality of traumatic patients is not still well recognized.

Aim:

The aim of this study was to investigate the prognostic value of cardiac troponin I and T on admission in mortality of multiple trauma patients admitted to the emergency department.

Methods:

In this prospective follow-up study, the cardiac troponin I and T levels were measured in patients with multiple trauma referring to the emergency department (ED) between March 2014 and February 2015 at Imam Khomeini Hospital, Sari, Iran. Patients were followed prospectively until discharge from hospital or death.

Results:

The levels of cardiac troponins I and T in patients with multiple trauma were significantly associated with their mortality, especially at the level of 0.5 and 1.2 μg/dl (p<0.05). Multivariate regression analysis showed association of level of cardiac troponin I and T with patients’ mortality, after controlling for patients’ age, vital signs and GCS on admission. The sensitivity and specificity of troponin I at levels greater than 0.4 μg/dl in predict mortality in this study were as 65.5% and 55.3%, while the values for troponin T were 65.1% and 54.9%, respectively.

Conclusion:

Elevated cardiac troponin I and T levels provide excellent prognostic information regarding mortality in patients with multiple-trauma, independent of age, hemodynamic variables and GCS score.

Mortality in sepsis: Comparison of outcomes between patients with demand ischemia, acute myocardial infarction, and neither demand ischemia nor acute myocardial infarction

INTRODUCTION

Elevation in cardiac troponins is common with sepsis despite unclear impact.

HYPOTHESIS

We investigated whether demand ischemia(DI) resulted in variable outcomes compared to acute myocardial infarction(AMI) and those with neither DI nor AMI in sepsis.

METHODS

We analyzed data from the 2011-2014 National Inpatient Sample among patients admitted for sepsis. We compared outcomes among patients with DI i) versus AMI and ii) versus neither DI nor AMI, respectively using propensity matching. Primary study end-point was in-hospital mortality.

RESULTS

We studied 666,154 patients, with mean age 63.7 years and 50.8% female participants. Overall, 94.7% of the included patients had neither DI nor AMI, 4.4% had AMI and 0.83% had DI. Between 2011 and 2014, we observed an increasing trend for DI but decreasing trend for AMI in sepsis. Patients with DI experienced higher rates of atrial and ventricular arrhythmias, had longer length of stay and higher cost of stay compared to patients with neither demand ischemia nor AMI. Despite higher hospital mortality at baseline with DI, post-propensity matching revealed no difference in hospital mortality between patients with DI and those with neither (26.9% vs. 27.0%, adjusted odds ratio 0.99, 95% confidence intervals 0.92-1.07;p=0.87). Patients with DI experienced lower hospital mortality compared to those with AMI pre (28.5% vs. 48.3%;p<0.001) and post-propensity matching (41.1% vs. 29.1%, aOR 0.58, 95% CI 0.54-0.63;p<0.001).

CONCLUSION

Among patients with sepsis, those with DI had similar adjusted in-hospital mortality compared to those with neither DI nor AMI. Patients with AMI had the highest in-hospital mortality among all groups.

Acute pancreatitis conditioned mesenteric lymph causes cardiac dysfunction in rats independent of hypotension

BACKGROUND

Critical illness including severe acute pancreatitis is associated with the multiple organ dysfunction syndrome. The "gut-lymph" hypothesis states that multiple organ dysfunction syndrome is due to release of toxic factors from the intestine into the mesenteric lymph. The aims of this study were to determine the effect of normotensive acute pancreatitis conditioned mesenteric lymph on cardiac function and whether external drainage of mesenteric lymph would protect the heart.

METHODS

Groups of normal rats and those with normotensive taurocholate induced acute pancreatitis, had either no lymphatic intervention or thoracic duct ligation and external drainage of mesenteric lymph. After 6 hours, the hearts were removed for ex vivo functional measurements, including cardiac output, ventricular contractility (+dP/dt), and relaxation (-dP/dt). In a second experiment, mesenteric lymph from normal rats and those with established acute pancreatitis was infused into ex vivo perfused normal working rat hearts to assess impact on cardiac function. Heart and lung tissues were collected for assessment of edema.

RESULTS

Significant cardiac dysfunction, denoted by decreased cardiac output (21%), contractility (37%), relaxability (23%), and increased cardiac tissue edema (2-fold), developed in rats with established acute pancreatitis and no lymphatic intervention compared with the control group (all P < .05). Strikingly this cardiac dysfunction and edema was normalized in acute pancreatitis rats that had undergone prior thoracic duct ligation and external drainage of mesenteric lymph. In the second experiment, infusion of acute pancreatitis conditioned mesenteric lymph resulted in an immediate and significant similar magnitude decrease in of cardiac output (17%), contractility (22%), and relaxation (27%) compared with the infusion of normal lymph (all P <.05).

CONCLUSION

Mesenteric lymph from normotensive acute pancreatitis animals caused significant cardiac dysfunction which could be prevented by thoracic duct ligation and external drainage of mesenteric lymph.

Anesthesia for Patients with Concomitant Sepsis and Cardiac Dysfunction

Anesthesiologists faced with a patient with sepsis and concurrent cardiac dysfunction must be cognizant of the patient's cardiac status and cause of the cardiac problem to appropriately adapt physiologic and metabolic monitoring and anesthetic management. Anesthesia in such patients is challenging because the interaction of sepsis and cardiac dysfunction greatly complicates management. Intraoperative anesthesia management requires careful induction and maintenance of anesthesia; optimizing intravascular volume status; avoiding lung injury during mechanical ventilation; and close monitoring of arterial blood gases, serum lactate concentrations, and hematology renal and electrolyte parameters. Such patients have increased mortality because of their inability to adequately compensate for the cardiovascular changes caused by sepsis.

Use of Admission Troponin in Critically Ill Medical Patients

Serum troponin I (TnI) is a sensitive marker of cardiac injury. A relation between elevated TnI and mortality has been suggested. In this retrospective chart review of 221 patients admitted to the medical intensive care unit (MICU) during a 6-month period, the authors studied the use of admission TnI levels in predicting mortality in MICU-admitted patients. Data retrieved included demographics, admission diagnosis, troponin, electrocardiogram, Acute Physiology and Chronic Health Evaluation (APACHE) II score, echocardiogram, requirements for mechanical ventilation and vasopressor support, development of multiorgan failure, mortality, and discharge disposition. There were 132 patients for whom TnI level was sent within 24 hours of admission; these patients comprised the study group. The median age was 70 years; 59% were female. The mean APACHE II score was 22. Troponin I was positive in 31% of patients (median level, 0.4 Ug/L; range 0-358 Ug/L). The hospital mortality was 39%. Positive TnI showed a weak association with intensive care unit (ICU) mortality ( P= .049) but not with overall mortality. There was no significant correlation between admission TnI concentration and APACHE II score ( P= .33), administration of vasopressor medications ( P= .115), or development of multiorgan failure ( P= .64). The authors concluded that there is no benefit in obtaining a routine admission troponin level in MICU patients when an acute coronary event is not suspected.

Cardiac Troponins in Dogs and Cats

Cardiac troponins are sensitive and specific markers of myocardial injury. The troponin concentration can be thought of as a quantitative measure of the degree of injury sustained by the heart, however, it provides no information on the cause of injury or the mechanism of troponin release. Conventionally, the cardiac troponins have been used for diagnosis of acute myocardial infarction in humans and have become the gold standard biomarkers for this indication. They have become increasingly recognized as an objective measure of cardiomyocyte status in both cardiac and noncardiac disease, supplying additional information to that provided by echocardiography and ECG. Injury to cardiomyocytes can occur through a variety of mechanisms with subsequent release of troponins. Independent of the underlying disease or the mechanism of troponin release, the presence of myocardial injury is associated with an increased risk of death. As increasingly sensitive assays are introduced, the frequent occurrence of myocardial injury is becoming apparent, and our understanding of its causes and importance is constantly evolving. Presently troponins are valuable for detecting a subgroup of patients with higher risk of death. Future research is needed to clarify whether troponins can serve as monitoring tools guiding treatment, whether administering more aggressive treatment to patients with evidence of myocardial injury is beneficial, and whether normalizing of troponin concentrations in patients presenting with evidence of myocardial injury is associated with reduced risk of death.

Type 2 myocardial infarction: the chimaera of cardiology?

The term type 2 myocardial infarction first appeared as part of the universal definition of myocardial infarction. It was introduced to cover a group of patients who had elevation of cardiac troponin but did not meet the traditional criteria for acute myocardial infarction although they were considered to have an underlying ischaemic aetiology for the myocardial damage observed. Since first inception, the term type 2 myocardial infarction has always been vague. Although attempts have been made to produce a systematic definition of what constitutes a type 2 myocardial infarction, it has been more often characterised by what it is not rather than what it is. Clinical studies that have used type 2 myocardial infarction as a diagnostic criterion have produced disparate incidence figures. The range of associated clinical conditions differs from study to study. Additionally, there are no agreed or evidence-based treatment strategies for type 2 myocardial infarction. The authors believe that the term type 2 myocardial infarction is confusing and not evidence-based. They consider that there is good reason to stop using this term and consider instead the concept of secondary myocardial injury that relates to the underlying pathophysiology of the primary clinical condition.

The impact of cardiac dysfunction on acute respiratory distress syndrome and mortality in mechanically ventilated patients with severe sepsis and septic shock: an observational study

PURPOSE

Acute respiratory distress syndrome (ARDS) is associated with significant mortality and morbidity in survivors. Treatment is only supportive, therefore elucidating modifiable factors that could prevent ARDS could have a profound impact on outcome. The impact that sepsis-associated cardiac dysfunction has on ARDS is not known.

MATERIALS AND METHODS

In this retrospective observational cohort study of mechanically ventilated patients with severe sepsis and septic shock, 122 patients were assessed for the impact of sepsis-associated cardiac dysfunction on incidence of ARDS (primary outcome) and mortality.

RESULTS

Sepsis-associated cardiac dysfunction occurred in 44 patients (36.1%). There was no association of sepsis-associated cardiac dysfunction with ARDS incidence (p= 0.59) or mortality, and no association with outcomes in patients that did progress to ARDS after admission. Multivariable logistic regression demonstrated that higher BMI was associated with progression to ARDS (adjusted OR 11.84, 95% CI 1.24 to 113.0, p= 0.02).

CONCLUSIONS

Cardiac dysfunction in mechanically ventilated patients with sepsis did not impact ARDS incidence, clinical outcome in ARDS patients, or mortality. This contrasts against previous investigations demonstrating an influence of nonpulmonary organ dysfunction on outcome in ARDS. Given the frequency of ARDS as a sequela of sepsis, the impact of cardiac dysfunction on outcome should be further studied.

Comparison of outcomes from sepsis between patients with and without pre-existing left ventricular dysfunction: a case-control analysis

Introduction

The aim of this study was to determine if there are differences between patients with pre-existing left ventricular dysfunction and those with normal antecedent left ventricular function during a sepsis episode in terms of in-hospital mortality and mortality risk factors when treated in accordance with a sepsis treatment algorithm.

Methods

We performed a retrospective case-control analysis of patients selected from a quality improvement database of 1,717 patients hospitalized with sepsis between 1 January 2005 and 30 June 2010. In this study, 197 patients with pre-existing left ventricular systolic dysfunction and sepsis were compared to 197 case-matched patients with normal prior cardiac function and sepsis.

Results

In-hospital mortality rates (P = 0.117) and intubation rates at 24 hours (P = 0.687) were not significantly different between cases and controls. There was no correlation between the amount of intravenous fluid administered over the first 24 hours and the PaO₂/FiO₂ ratio at 24 hours in either cases or controls (r² = 0.019 and r² = 0.001, respectively). Mortality risk factors for cases included intubation status (P = 0.016, OR = 0.356 for no intubation), compliance with a sepsis bundle (P = 0.008, OR = 3.516 for failed compliance), a source of infection other than the lung (P = 0.019, OR = 2.782), and the initial mixed venous oxygen saturation (P = 0.004, OR = 0.997). Risk factors for controls were the initial platelet count (P = 0.028, OR = 0.997) and the serum lactate level (P = 0.048, OR = 1.104). Patients with pre-existing left ventricular dysfunction who died had a lower initial mean mixed venous oxygen saturation than those who survived (61 ± 18% versus 70 ± 16%, P = 0.002).

Conclusions

Clinical outcomes were not different between septic patients with pre-existing left ventricular dysfunction and those with no cardiac disease. There was no correlation between fluid administration and oxygenation at 24 hours in either cohort. The mortality risk factor profile of patients with pre-existing left ventricular dysfunction was different when compared with control patients, and may be related to oxygen delivery determinants.

Qualification of cardiac troponins for nonclinical use: a regulatory perspective

The US Food and Drug Administration (FDA) Biomarker Qualification Review Team presents its perspective on the recent qualification of cardiac troponins for use in nonclinical safety assessment studies. The goal of this manuscript is to provide greater transparency into the qualification process and factors that were considered in reaching a regulatory decision. This manuscript includes an overview of the data that were submitted and a discussion of the strengths and shortcomings of these data supporting the qualification decision. The cardiac troponin submission is the first literature-based biomarker application to be reviewed by the FDA and insights gained from this experience may aid future submissions and help streamline the characterization and qualification of future biomarkers.

Association between troponin T and ICU mortality, a changing trend

Background

Initially elevated levels of troponin predict adverse outcomes in patients admitted to the intensive care unit (ICU). No research team has investigated the changes in concentration of cardiac troponin T (cTnT) during ICU stay and their association with patient outcome.

Objective

We investigated whether the change in cTnT levels during ICU stay could predict outcomes (death or survival).

Methods

In this cohort study, all patients admitted to the medical ICU (10 beds) from January to July 2008 were enrolled. Troponin levels were evaluated within the first 24 hours of ICU admission and on the fourth, seventh and 10th days after admission.

Results

The study population (135 patients) had a mean age of 60.9 ± 21.5 years. The outcome was significantly different with regard to normal or elevated cTnT concentrations on the first and seventh days of follow up (p = 0.03 and 0.023, respectively). This difference was non-significant for cTnT levels on the fourth and 10th days after admission (p = 0.69 and 0.78, respectively). The change in cTnT levels was not significantly different between the deceased and discharged patients (p = 0.4).

Conclusion

Changes in cTnT levels during ICU stay did not show a significant trend (power: 0.26). Patients whose cTnT levels were increased on the first and seventh days of ICU stay had a worse survival, which could be associated with cardiac events on admission or at specific times during the stay in ICU.

Cardiac biomarkers in the critically ill

Cardiac biomarkers have well-established roles in acute coronary syndrome and congestive heart failure. In many instances, the detection of cardiac biomarkers may aid in the diagnosis and risk assessment of critically ill patients. Despite increasing interest in the use of cardiac biomarkers in noncardiac critical illness, no clear consensus exists on how and in which settings markers should be measured. This article briefly describes what constitutes an ideal biomarker and focuses on those that have been most well studied in critical illness, specifically troponin, the natriuretic peptides, and heart-type fatty acid-binding protein.

Biomonitors of cardiac injury and performance: B-type natriuretic peptide and troponin as monitors of hemodynamics and oxygen transport balance

Serum biomarkers, such as B-type natriuretic peptide and troponin, are frequently measured in the cardiac intensive care unit. A review of the evidence supporting monitoring of these biomarkers is presented.

DESIGN

A search of MEDLINE, PubMed, and the Cochrane Database was conducted to find literature regarding the use of B-type natriuretic peptide and troponin in the cardiac intensive care setting. Adult and pediatric data were considered.

RESULTS AND CONCLUSION

Both B-type natriuretic peptide and troponin have demonstrated utility in the intensive care setting but there is no conclusive evidence at this time that either biomarker can be used to guide inpatient management of children with cardiac disease. Although B-type natriuretic peptide and troponin concentrations can alert clinicians to myocardial stress, injury, or hemodynamic alterations, the levels can also be elevated in a variety of clinical scenarios, including sepsis. Observational studies have demonstrated that perioperative measurement of these biomarkers can predict postoperative mortality and complications.

RECOMMENDATION AND LEVEL OF EVIDENCE

(class IIb, level of evidence B): The use of B-type natriuretic peptide and/or troponin measurements in the evaluation of hemodynamics and postoperative outcome in pediatric cardiac patients may be beneficial.

The clinical significance of cardiac troponins in medical practice

Troponins are regulatory proteins that form the cornerstone of muscle contraction. The amino acid sequences of cardiac troponins differentiate them from that of skeletal muscles, allowing for the development of monoclonal antibody-based assay of troponin I (TnI) and troponin T (TnT). Along with the patient history, physical examination and electrocardiography, the measurement of highly sensitive and specific cardiac troponin has supplanted the former gold standard biomarker (creatine kinase-MB) to detect myocardial damage and estimate the prognosis of patients with ischemic heart disease. The current guidelines for the diagnosis of non-ST segment elevation myocardial infarction are largely based on an elevated troponin level. The implementation of these new guidelines in clinical practice has led to a substantial increase in the frequency of myocardial infarction diagnosis. Automated assays using cardiac-specific monoclonal antibodies to cardiac TnI and TnT are commercially available. They play a major role in the evaluation of myocardial injury and prediction of cardiovascular outcome in cardiac and non-cardiac causes. In this review we discuss the clinical applications of cardiac troponins and the interpretation of elevated levels in the context of various clinical settings.

Acute left ventricular dysfunction in the critically ill

Acute left ventricular (LV) dysfunction is common in the critical care setting and more frequently affects the elderly and patients with comorbidities. Because of increased mortality and the potential for significant improvement with early revascularization, the practitioner must first consider acute coronary syndrome. However, variants of stress (takotsubo) cardiomyopathy may be more prevalent in ICU settings than previously recognized. Early diagnosis is important to direct treatment of complications of stress cardiomyopathy, such as dynamic LV outflow tract obstruction, heart failure, and arrhythmias. Global LV dysfunction occurs in the critically ill because of the cardio-depressant effect of inflammatory mediators and endotoxins in septic shock as well as direct catecholamine toxicity. Tachycardia, hypertension, and severe metabolic abnormalities can independently cause global LV dysfunction, which typically improves with addressing the precipitating factor. Routine troponin testing may help early detection of cardiac injury and biomarkers could have prognostic value independent of prior cardiac disease. Echocardiography is ideally suited to quantify LV dysfunction and determine its most likely cause. LV dysfunction suggests a worse prognosis, but with appropriate therapy outcomes can be optimized.

Sepsis and the heart

Septic shock, the most severe complication of sepsis, accounts for approximately 10% of all admissions to intensive care. Our understanding of its complex pathophysiology remains incomplete but clearly involves stimulation of the immune system with subsequent inflammation and microvascular dysfunction. Cardiovascular dysfunction is pronounced and characterized by elements of hypovolaemic, cytotoxic, and distributive shock. In addition, significant myocardial depression is commonly observed. This septic cardiomyopathy is characterized by biventricular impairment of intrinsic myocardial contractility, with a subsequent reduction in left ventricular (LV) ejection fraction and LV stroke work index. This review details the myocardial dysfunction observed in adult septic shock, and discusses the underlying pathophysiology. The utility of using the regulatory protein troponin for the detection of myocardial dysfunction is also considered. Finally, options for the management of sepsis-induced LV hypokinesia are discussed, including the use of levosimendan.

Role of tissue disorder markers in the evaluation of disease progress and outcome prediction: a prospective cohort study in non-cardiac critically ill patients

BACKGROUND

Acute Physiology and Chronic Health Evaluation (APACHE) has a remarkable association with clinical syndrome, life expectancy, and length of ward stay. But the defects are obvious. It is crucial to detect an effective and convenient evaluation method to monitor disease progress and predict outcome.

OBJECTIVE

To determine whether myoglobin (Mb) and other five tissue disorder biomarkers, troponin-I, creatine-kinase, creatine kinase-muscle brain, aspartate aminotransferase, and lactate dehydrogenase are independent predictors of disease progress and mortality in non-cardiac critical illness.

METHODS

A prospective study with 179 patients admitted to the Intensive Care Unit was conducted. All serum tissue disorder markers and APACHE-II score were measured within 24  hr of admission.

RESULTS

All the six biomarkers were significantly correlated with disease severity stratified by APACHE-II and outcome. Serial blood samples were taken from 17 patients on detection of two new organs failure. The occurrence of organs failure was significantly associated with the elevation of Mb, troponin-I, and APACHE-II. Multivariate analysis demonstrated that elevated Mb was the principal risk factor related to mortality either during hospitalization or 180-day followup. Kaplan-Meier method and log-rank test also showed that patients with elevated Mb levels had significantly shorter survival. The mortality was higher in patients with both Mb>500  ng/ml and APACHE-II>20 than in those with only Mb>500  ng/ml or APACHE-II>20.

CONCLUSION

All the six tissue disorder markers are predictors of disease severity, organ failure, and outcome in non-cardiac critically illness. Among them, Mb plays a pivotable role. The combined use of Mb and APACHE-II suggest an effective method to determine the outcome of critical ill syndrome.

Relationships between Brain Natriuretic Peptide, Troponin I and QT Dispersion in Asymptomatic Dialysis Patients

OBJECTIVES

The relationships between increased wall stress, myocyte death, and ventricular repolarization instability in patients with heart failure were reported.

DESIGN AND METHODS

The relationships between brain natriuretic peptide (BNP), a predictor of increased wall stress of hearth; troponin I (cTnI), a predictor of myocyte death; and QT dispersion (QTd), a reflection of ventricular repolarization instability were evaluated in age- and sex-matched asymptomatic 29 hemodialysis (HD) patients and 26 peritoneal dialysis (PD) patients, and the finding were compared.

RESULTS

Serum BNP and cTnI levels in HD patients (722.9 +/- 907.9 pg/mL, 0.05 +/- 0.07 microg/L, respectively), just before HD, were significantly higher than those of PD patients (255.4 +/- 463.7 pg/mL, 0.02 +/- 0.02 microg/L, respectively; p < 0.05). There was no significant difference between groups with regard to corrected QTd and maximum and minimum QT intervals (p > 0.05). Serum cTnI levels were significantly and positively correlated with serum BNP levels in both dialysis groups (r = 0.447, p = 0.048). No relationship was found between plasma BNP and ECG parameters studied in both groups (p > 0.05).

CONCLUSION

Increased serum cTnI levels were associated with elevated BNP levels in both dialysis groups. The increases in BNP and troponin I are more likely to reflect hypervolemia. Although CAPD patients were receiving dialysis daily and HD patients were more hypervolemic, CAPD patients have similar QTdc and accordingly a similar tendency toward arrhythmias. This suggests that factors other than electromechanical interaction may be important in determining the QT interval length in patients on dialysis.

Myocardial cell injury is common in children with septic shock

OBJECTIVE

To determine the prevalence of myocardial cell injury in children with septic shock by estimating the levels of biochemical markers of myocardial injury, troponin I (TnI) and creatine kinase MB (CK-MB).

PATIENTS

Children aged 3 months to 16 years were admitted to paediatric intensive care unit (PICU) with septic shock. Children with sepsis without shock and children with hypovolaemic shock were enrolled as controls.

MEASUREMENTS AND MAIN RESULTS

Serum TnI and CK-MB levels were measured at admission and serially at 24 h, 48 h and 96 h in children with septic shock, while baseline measurement of the same markers was taken from the controls. In total, 88% (15/18) of children with septic shock had elevated TnI levels compared with 25% (5/20) with sepsis and 6.7% (1/15) with hypovolaemic shock (p < 0.001). Serial TnI levels at admission, 24 h, 48 h and 96 h were higher in the nonsurvivors. There was a positive correlation between the baseline TnI levels and the predicted mortality using the paediatric index of mortality (PIM2) scores at admission (r = 0.51, p = 0.03).

CONCLUSION

A majority of children with septic shock have evidence of myocardial cell injury. The estimation of serum TnI levels may help in better prognostication of children with septic shock.

Prognostic implications of normal (<0.10 ng/ml) and borderline (0.10 to 1.49 ng/ml) troponin elevation levels in critically ill patients without acute coronary syndrome

Borderline increase of troponin I (cTnI) is associated with higher rates of cardiovascular events compared with normal levels in the setting of acute coronary syndrome (ACS), but the significance of borderline cTnI levels in patients without chest pain may differ. The aim of this study was to determine the prognostic implications of intermediate serum cTnI levels in patients without ACS in the intensive care unit (ICU). This was a 12-month retrospective study of 240 patients without ACS in the ICU with normal (<0.1 ng/ml) or intermediate (0.1 to 1.49 ng/ml) cTnI levels. End points included in-hospital mortality, lengths of ICU and hospital stays, and rates of postdischarge readmission and mortality. Overall in-hospital mortality was 13%, with 5% in the normal cTnI group and 28% in the intermediate cTnI group. By multivariate analysis, intermediate cTnI was independently associated with in-hospital mortality (p = 0.004) and length of ICU stay (p = 0.028). The only other independent risk factor for inpatient mortality was a standardized ICU prognostic measurement (Simplified Acute Physiology Score II score). Intermediate cTnI had no prognostic implications regarding length of hospital stay, readmission rate, or postdischarge mortality at 6 months. In conclusion, an intermediate level of cTnI in patients without ACS in the ICU is an independent prognostic marker predicting in-hospital mortality and length of ICU stay. Patients with intermediate cTnI levels who survive to discharge have equivalent out-of-hospital courses for up to 6 months compared with patients with normal cTnI levels.

Relation of troponin elevation to outcome in patients with infective endocarditis

Elevated troponin is increasingly recognized as a marker of cardiac injury and poor outcomes in diverse disease states. It was hypothesized that patients with infective endocarditis (IE) and elevated cardiac troponin would have more extensive IE and worse clinical outcomes. Patients were enrolled as part of the International Collaboration on Endocarditis (ICE) prospective cohort study; analysis of these patients was done retrospectively. Data from 83 consecutively enrolled patients from a single center were evaluated. Cardiac troponin I (cTnI) was drawn for clinical indications and before any cardiac surgery in 51 of the 83 patients. Outcomes evaluated were hospital mortality, annular or myocardial abscess on the basis of echocardiography or surgery, and central nervous system events. Of 51 patients with cTnI drawn, 33 (65%) had elevated cTnI > or =0.1 mg/dl. There were no differences in age, gender, prosthetic valve IE, Staphylococcus aureus IE, or history of coronary artery disease, congestive heart failure, or diabetes mellitus between patients with and without cTnI elevations. Patients with elevated cTnI were less likely to have isolated right-sided IE and more likely to have left ventricular systolic dysfunction or renal dysfunction (p <0.05 for each). In conclusion, elevated cTnI was associated with the composite of death, abscess, and central nervous system events (p <0.001).

Positive troponin in diabetic ketoacidosis without evident acute coronary syndrome predicts adverse cardiac events

BACKGROUND

Elevated troponin I has been associated with increased mortality in critically ill patients without acute coronary syndrome (ACS). However, the prognostic significance of troponin elevation in patients with diabetic ketoacidosis (DKA) without evident ACS has not been studied.

METHODS

Retrospective study of all patients admitted to a U.S. tertiary center between 01/98 and 12/00 with DKA and had troponin I level measured. Patients with evidence of ACS or who met the American College of Cardiology/European Society of Cardiology (ACC/ESC) definition for myocardial infarction were excluded. Baseline characteristics, cardiac evaluation and 2 year major adverse coronary event (MACE) rate were compared between patients with positive and negative troponin.

RESULTS

Ninety-six patients fulfilled the inclusion criteria of this study, 26 had positive troponin. There were no differences in baseline characteristics between the two groups. After a 2 year follow-up, there was significantly increased mortality in patients with elevated troponin (50.0% versus 27.1%, hazard-ratio (HR) 2.3, 95% confidence interval (CI) 1.2-4.8, p = 0.02). Patients with elevated troponin also had significantly increased MACE rate at 2 years (50.0% versus 28.6%, HR 2.6, 95% CI 1.3-5.3, p = 0.007) driven primarily by mortality. Using Cox Proportional Hazard Analysis, elevated troponin was a predictor of increased MACE after adjusting for confounding variables. (Adjusted HR 2.3, 95% CI 1.1-4.6, p = 0.02)

CONCLUSIONS

Elevated troponin I in diabetic patients admitted with DKA identifies a group at very high risk for future cardiac events and mortality. Whether cardiac risk stratification of these patients will improve long term outcome remains to be studied.

Troponin I in the intensive care unit setting: from the heart to the heart

When measured in the plasma, cardiac troponins T (cTnT) and I (cTnI) are considered to be highly specific markers of myocardial cell damage; however, research has demonstrated that troponin elevation may associated with causes other than coronary artery disease. In the intensive care unit (ICU) setting, increased cTnI levels are quite common findings and when documented, even on admission, intensivists should bear in mind that this laboratory finding holds a prognostic role independent of the reason for ICU admission. The mechanism(s) (such as demand ischemia, myocardial strain, etc.) and not simply the cause (i.e., renal failure) of the increment in serum cTnI should be investigated to better tailor the therapeutical regimen in the single patient. In this review, we therefore consider the nonthrombotic causes of troponin elevation in the critical setting.

Use and Misuse of Cardiac Troponins in Clinical Practice

Cardiac troponins are very sensitive and specific markers of myocardial injury. Elevated troponin levels in the setting of acute coronary syndrome are diagnostic of acute myocardial infarction and provide guidance to clinicians with regard to appropriate use of intensive medical and revascularization therapies. However, elevated troponin levels are commonly seen in several noncoronary ischemia presentations and create considerable confusion among clinicians in these settings. In this review article, we discuss the utility of troponins in various clinical settings and present a "common sense" approach to interpreting troponin elevation outside the setting of acute coronary syndrome.

Cardiac troponins in the intensive care unit: common causes of increased levels and interpretation

BACKGROUND AND OBJECTIVES

Clinical chemistry is an important component of the diagnosis of many conditions, and advances in laboratory science have brought many new diagnostic tools to the intensive care unit clinician, including new biomarkers of cardiac injury like troponin T and I. Interpretation of these clinical laboratory results requires knowledge of the performance of these tests.

SETTING AND PATIENTS

This article reviews the interpretation and performance of diagnostic markers of myocardial injury in patients with diverse clinical conditions of interest to critical care practitioners.

CONCLUSIONS

Cardiac troponin I and T, regulatory components of the contractile apparatus, are sensitive indicators of myocardial injury and have become central to the diagnosis of myocardial infarction. The troponins are also released in a number of clinical situations in which thrombotic complications of coronary artery disease and resultant acute myocardial infarction have not occurred. These situations include conditions like pulmonary embolism, sepsis, myocarditis, and acute stroke. Elevated troponins in these conditions are thought to emanate from injured myocardial cells and, in most circumstances, have been associated with adverse outcomes. Practitioners should be mindful of the wide spectrum of diseases that may result in elevated troponin when interpreting these measurements.

Valeurs de la troponine I au cours des rhabdomyolyses chez les personnes âgées admises aux urgences

OBJECTIVE

The objective of this study was to assess the utility of determining serum cardiac troponin I (TcI) levels in the elderly.

METHODS

During the nine-month study period, all patients older than 70 years admitted to the emergency department presenting rhabdomyolysis (defined by creatine kinase>500 IU/L) were included in this prospective descriptive study, except for those with acute coronary syndrome or pulmonary embolism. Patients were classified into two groups according to their serum TcI level:>0.15 or<or=0. 15 ng/mL. The groups were compared for clinical, laboratory and treatment variables at inclusion and for mortality at six months.

RESULTS

The study included 67 patients: 30 in the group with TcI>0.15 ng/mL group and 37 in the other group. Clinical and laboratory indicators were similar in the two groups. In contrast, significantly more patients in the TcI>0.15 ng/mL group had been treated with a curative dose of heparin (14 versus 2, p=0.01). This difference between the two groups was noted in both the emergency department and other hospital units. Serum TcI levels were not correlated with creatine kinase levels. Concordance between emergency department diagnosis and discharge diagnosis was 95%. No patient was discharged with a diagnosis of acute coronary syndrome; one patient, with a serum TcI level<or=0.15 ng/mL, was diagnosed with a pulmonary embolism. Fewer than half the patients underwent cardiac ultrasonography. Segmental hypokinesia was observed in only a few cases (6% in the TcI>0. 15 ng/mL group versus 8% in the other group). Mortality at six months was higher among patients with an elevated serum TcI level, but the difference was not significant (23% versus 8%, p=0.07).

CONCLUSION

This study indicated a trend toward higher mortality among patients with elevated serum TcI levels, although the factors underlying these increased concentrations remain unclear.

Plasma level of N terminal pro-brain natriuretic peptide as a prognostic marker in critically ill patients

We studied whether N-terminal pro brain natriuretic peptide (NT-pro BNP) measured at intensive care unit admission is an independent predictor of mortality in critically ill patients. We conducted a prospective observational cohort study enrolling 78 patients with APACHE II scores more than 12. Serum NT-pro BNP and cardiac troponin T were measured at admission, and echocardiography was performed within 24 h. The primary end-point was 30-day mortality. The median NT-pro BNP levels of the 22 (28.2%) patients who died were significantly more frequent than that of those who survived (8328 versus 1016 pg/mL; P = 0.001). Patients with NT-pro BNP levels more than 1900 pg/mL had significantly more frequent mortality (47.2% versus 11.9%; P = 0.03). This group also had more frequent moderate to severe left ventricular dysfunction (30.6% versus 9.5%; P = 0.02) and abnormal cardiac troponin T levels (33.3% versus 14.3%; P = 0.05). Multivariate analyses adjusted for APACHE-II revealed that a NT-pro BNP level more than 1900 pg/mL is an independent predictor of mortality.

Sepsis-associated myocardial dysfunction: diagnostic and prognostic impact of cardiac troponins and natriuretic peptides

Myocardial dysfunction, which is characterized by transient biventricular impairment of intrinsic myocardial contractility, is a common complication in patients with sepsis. Left ventricular systolic dysfunction is reflected by a reduced left ventricular stroke work index or, less accurately, by an impaired left ventricular ejection fraction (LVEF). Early recognition of myocardial dysfunction is crucial for the administration of the most appropriate therapy. Cardiac troponins and natriuretic peptides are biomarkers that were previously introduced for diagnosis and risk stratification in patients with acute coronary syndrome and congestive heart failure, respectively. However, their prognostic and diagnostic impact in critically ill patients warrants definition. The elevation of cardiac troponin levels in patients with sepsis, severe sepsis, or septic shock has been shown to indicate left ventricular dysfunction and a poor prognosis. Troponin release in this population occurs in the absence of flow-limiting coronary artery disease, suggesting the presence of mechanisms other than thrombotic coronary artery occlusion, probably a transient loss in membrane integrity with subsequent troponin leakage or microvascular thrombotic injury. In contrast to the rather uniform results of studies dealing with cardiac troponins, the impact of raised B-type natriuretic peptide (BNP) levels in patients with sepsis is less clear. The relationship between BNP and both LVEF and left-sided filling pressures is weak, and data on the prognostic impact of high BNP levels in patients with sepsis are conflicting. Mechanisms other than left ventricular wall stress may contribute to BNP release, including right ventricular overload, catecholamine therapy, renal failure, diseases of the CNS, and cytokine up-regulation. Whereas cardiac troponins may be integrated into the monitoring of myocardial dysfunction in patients with severe sepsis or septic shock to identify those patients requiring early and aggressive supportive therapy, the routine use of BNP and other natriuretic peptides in this setting is discouraged at the moment.

Clinical laboratory findings associated with in-hospital mortality

The diagnostic approach and the clinical management of critically ill patients is challenging. The recognition of biomarkers related to in-hospital mortality is of importance for identification of patients at increased risk of death. Many prediction models assessing the severity of illness and likelihood of hospital survival were developed using logistic regression analyses. These models include several laboratory parameters, such as white blood cell counts, serum bilirubin, serum albumin, blood glucose, serum electrolytes and markers which reflect acid-base disturbances. Recently, several other biomarkers, including troponin, B-type natriuretic peptide (BNP), N-terminal proBNP, C-reactive protein, procalcitonin, cholesterol and coagulation related markers have emerged as clinically useful tools for risk stratification and mortality prediction of heterogeneous and more specific subgroups of critically ill patients. More investigations are required to verify whether risk stratification based on mortality-related biomarkers may translate into targeted treatment strategies to improve clinical outcome of the critical illness. Biomarkers which are related to in-hospital mortality are highlighted in the current review.

Elevated Cardiac Troponin Levels in Critically Ill Patients: Prevalence, Incidence, and Outcomes

• Background Levels of cardiac troponin, a sensitive and specific marker of myocardial injury, are often elevated in critically ill patients.

• Objectives To document elevated levels of cardiac troponin I in patients in a medical-surgical intensive care unit and the relationship between elevated levels and electrocardiographic findings and mortality.

• Methods A total of 198 patients expected to remain in the intensive care unit for at least 72 hours were classified as having myocardial infarction (cardiac troponin I level ≥1.2 μg/L and ischemic electrocardiographic changes), elevated troponin level only (≥1.2 μg/L and no ischemic electrocardiographic changes), or normal troponin levels. Events were classified as prevalent if they occurred within 48 hours after admission and as incident if they occurred 48 hours or later after admission. Factors associated with mortality were examined by using regression analysis.

• Results A total of 171 patients had at least one troponin level measured in the first 48 hours. The prevalence of elevated troponin level was 42.1% (72 patients); 38 patients (22.2%) had myocardial infarction, and 34 (19.9%) had elevated troponin level only. After the first 48 hours, 136 patients had at least 1 troponin measurement. The incidence of elevated troponin level was 11.8% (16 patients); 7 patients (5.1%) met criteria for myocardial infarction, and 2 (1.5%) had elevated troponin level only. Elevated levels of troponin I at any time during admission were associated with mortality in the univariate but not the multivariate analysis.

• Conclusions Elevated levels of cardiac troponin I in critically ill patients do not always indicate myocardial infarction or an adverse prognosis.

Prevalence and clinical significance of an elevated cardiac troponin I in patients presenting to the Emergency Department without chest pain

BACKGROUND

Cardiac troponins are currently measured in patients presenting with chest pain. Little is known about routinely measured cardiac troponins in patients presenting without chest pain. The aim of this study was to determine the prevalence and clinical significance of an elevated cardiac troponin I (cTnI) in patients presenting to the Emergency Department without chest pain.

METHODS

During a 6-month period, we routinely measured cTnI in all patients presenting to the internist, neurologist, or lung specialist for reasons other than chest pain. We followed patients with an elevated cTnI for 1 year and determined mortality and incidence of non-fatal myocardial infarction, percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG).

RESULTS

cTnI was elevated in 41 out of 1130 patients (3.6%). Patients with an elevated cTnI were older (78 vs. 62 years) and more often admitted to the hospital (95% vs. 78%) than those with a normal cTnI. Twenty-six patients (63%) with an elevated cTnI died within 1 year. Approximately 50% of these deaths were cardiac-related. Two patients (4.9%) suffered a non-fatal myocardial infarction, while no patient underwent PCI or CABG during follow-up.

CONCLUSION

Routinely measured cTnI is seldom elevated in a general population of patients presenting to the Emergency Department without chest pain. Patients with an elevated cTnI are, on the average, 16 years older than those with a normal level. An elevated cTnI is clearly associated with an unfavorable outcome.

Myocardial injury in critically ill patients: relation to increased cardiac troponin I and hospital mortality

OBJECTIVE

To examine the relationship between myocardial injury, assessed by cardiac troponin I (cTnI) levels, and outcome in selected critically ill patients without acute coronary syndromes or cardiac dysfunction.

DESIGN AND SETTING

Prospective, observational study in the emergency ICU of a university teaching hospital.

POPULATION

Over a 6-month period, 217 consecutive patients admitted to the ICU were studied.

METHODS AND RESULTS

cTnI assays were performed in all patients on admission to the ICU. The incidence of myocardial injury, defined by cTnI level > 0.1 ng/mL, was 32% (69 of 217 patients). Overall mortality was 27% (58 of 217 patients). Patients with myocardial injury had a mortality rate of 51%, compared with only 16% mortality for those without myocardial injury (p < 0.001). The hospital mortality rate was highest among older patients (71 +/- 14% vs 58.5 +/- 20%, p < 0.0001) and patients with higher simplified acute physiology scale (SAPS) II score (62 +/- 25% vs 37 +/- 17%, p < 0.0001). Mechanical ventilation was associated with higher in-hospital death (50% vs 31%, for patients who died in the hospital vs those who were discharged alive; p = 0.03). Elevated blood levels of cTnI were found to be independently associated with hospital mortality, regardless of the presence of SAPS II score and mechanical ventilation, in the logistic regression analysis (odds ratio, 2.09; 95% confidence interval, 1.06 to 4.11; p = 0.01).

CONCLUSIONS

This study demonstrates the high frequency of myocardial injury (32%) in critically ill patients without acute coronary syndromes or cardiac dysfunction on admission to ICU. Myocardial injury is an independent determinant of hospital mortality. Assessment of myocardial injury on admission to ICU would make it possible to identify patients at increased risk of death.

Myocardial infarction complicating critical illness

Cardiac troponins are highly sensitive and specific indicators of myocardial injury. Although the mechanism of this injury is not entirely clear, it carries important prognostic information. Elevated serum levels of cardiac troponins have been described in a wide variety of conditions other than myocardial infarction (MI). The current study is an important first step in trying to determine the exact frequency of MI among critically ill patients with elevated troponin. At present, the rate of MI in these patients is unknown and its implications on outcome and management will have to await future prospective clinical trials.

Elevated troponin and myocardial infarction in the intensive care unit: a prospective study

INTRODUCTION

Elevated troponin levels indicate myocardial injury but may occur in critically ill patients without evidence of myocardial ischemia. An elevated troponin alone cannot establish a diagnosis of myocardial infarction (MI), yet the optimal methods for diagnosing MI in the intensive care unit (ICU) are not established. The study objective was to estimate the frequency of MI using troponin T measurements, 12-lead electrocardiograms (ECGs) and echocardiography, and to examine the association of elevated troponin and MI with ICU and hospital mortality and length of stay.

METHOD

In this 2-month single centre prospective cohort study, all consecutive patients admitted to our medical-surgical ICU were classified in duplicate by two investigators as having MI or no MI based on troponin, ECGs and echocardiograms obtained during the ICU stay. The diagnosis of MI was based on an adaptation of the joint European Society of Cardiology/American College of Cardiology definition: a typical rise or fall of an elevated troponin measurement, in addition to ischemic symptoms, ischemic ECG changes, a coronary artery intervention, or a new cardiac wall motion abnormality.

RESULTS

We screened 117 ICU admissions and enrolled 115 predominantly medical patients. Of these, 93 (80.9%) had at least one ECG and one troponin; 44 of these 93 (47.3%) had at least one elevated troponin and 24 (25.8%) had an MI. Patients with MI had significantly higher mortality in the ICU (37.5% versus 17.6%; P = 0.050) and hospital (50.0% versus 22.0%; P = 0.010) than those without MI. After adjusting for Acute Physiology and Chronic Health Evaluation II score and need for inotropes or vasopressors, MI was an independent predictor of hospital mortality (odds ratio 3.22, 95% confidence interval 1.04-9.96). The presence of an elevated troponin (among those patients in whom troponin was measured) was not independently predictive of ICU or hospital mortality.

CONCLUSION

In this study, 47% of critically ill patients had an elevated troponin but only 26% of these met criteria for MI. An elevated troponin without ischemic ECG changes was not associated with adverse outcomes; however, MI in the ICU setting was an independent predictor of hospital mortality.

Cardiac troponins in intensive care

The cardiac troponins are integral components of the myofibrillary apparatus and they regulate muscle contraction. The measurement of cardiac troponins has replaced other biomarkers for the specific detection of myocardial necrosis and for the diagnosis of myocardial infarction. The tissue specificity plus sensitivity of the measurement technology has meant that cardiac damage can be detected in circumstances other than conventional acute coronary syndromes. The ability to specifically detect cardiac damage as part of multiple organ failure in intensive care patients has been shown to provide prognostic information, but it is unclear whether this is a dependent or an independent marker of outcome.

The role of cardiac troponin I as a prognosticator in critically ill medical patients: a prospective observational cohort study

Introduction

Myocardial injury is frequently unrecognized in intensive care unit (ICU) patients. Cardiac troponin I (cTnI), a surrogate of myocardial injury, has been shown to correlate with outcome in selected groups of patients. We wanted to determine if cTnI level measured upon admission is an independent predictor of mortality in a heterogeneous group of critically ill medical patients.

Methods

We conducted a prospective observational cohort study; 128 consecutive patients admitted to a medical ICU at a tertiary university hospital were enrolled. cTnI levels were measured within 6 h of admission and were considered positive (>0.7 ng/ml) or negative. A variety of clinical and laboratory variables were recorded.

Results

Both cTnI positive and negative groups were similar in terms of age, sex and pre-admission co-morbidity. In a univariate analysis, positive cTnI was associated with increased mortality (OR 7.0, 95% CI 2.44–20.5, p < 0.001), higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores and a higher rate of multi-organ failure and sepsis. This association between cTnI and mortality was more pronounced among elderly patients (>65 years of age). Multivariate analysis controlling for APACHE II score revealed that elevated cTnI levels are not independently associated with 28-day mortality.

Conclusion

In critically ill medical patients, elevated cTnI level measured upon admission is associated with increased mortality rate. cTnI does not independently contribute to the prediction of 28-day mortality beyond that provided by APACHE II.

Cardiac troponin I predicts outcome after ruptured abdominal aortic aneurysm repair

Background

Cardiac troponin I (cTnI) is a highly sensitive and specific marker for myocardial injury that predicts mortality in patients with acute coronary syndromes. This study examined the relationship between perioperative cTnI levels and clinical outcome in patients with ruptured abdominal aortic aneurysm (AAA).

Methods

Consecutive patients who underwent operative repair of a ruptured AAA over a 22-month interval and survived for more than 24 h were entered into a prospective observational cohort study. Levels of cTnI were measured immediately before, and at 24 and 48 h after surgery, and related to clinical outcome.

Results

Of 62 patients who underwent attempted operative repair of ruptured AAA, 50 (81 per cent) survived for more than 24 h and were included in this study. Twenty-three (46 per cent) of the 50 had a detectable cTnI level at one or more time points during the first 48 h. Of these, 11 patients had clinical or electrocardiographic evidence of an acute cardiac event and 12 did not; five patients in each of these two groups died. Of 27 patients with no increase in cTnI in the first 48 h, only three died (P = 0·031 and P = 0·043 respectively, relative to the groups with detectable cTnI).

Conclusion

Approximately half of patients who survived repair of ruptured AAA for more than 24 h sustained a detectable myocardial injury within the first 48 h. A perioperative increase in the level of cTnI, with or without clinically apparent cardiac dysfunction, was associated with postoperative death.

B-type natriuretic peptide and the prediction of outcome in patients admitted to intensive care

B-type natriuretic peptide is known to predict outcome in congestive cardiac failure and myocardial infarction. We aimed to determine whether measurement of B-type natriuretic peptide would predict hospital mortality in patients admitted to an intensive care unit. We conducted a prospective observational cohort study in 78 consecutive patients. Demographics, clinical details and clinical outcomes were recorded. Admission and 24 h B-type natriuretic peptide and cardiac troponin I levels were measured. B-type natriuretic peptide and cardiac troponin I levels taken on intensive care admission and 24 h after admission did not accurately predict hospital mortality for all patients, including patients with severe sepsis or septic shock (all p > 0.05). B-type natriuretic peptide levels were higher in patients with severe sepsis and septic shock (p = 0.02), in patients > or = 65 years (p = 0.04) and in patients with raised creatinine > or = 110 micromol.l(-1) (p = 0.02). We concluded that B-type natriuretic peptide, measured soon after admission to intensive care, does not usefully predict outcome after intensive care.

Prognostic value of low-level cardiac troponin-I elevations in patients without definite acute coronary syndromes

BACKGROUND

Low-level cardiac troponin-I (cTn-I) elevations predict adverse cardiovascular outcomes in patients with definite acute coronary syndromes (ACS), as defined by the presence of chest pain accompanied by ischemic electrocardiographic changes. However, their prognostic value in other clinical situations remains unclear.

METHODS

We studied 366 patients with suspected myocardial infarction (MI) but without definite ACS, including 57 patients with low-level cTn-I elevations (1.0 to 3.0 ng/mL) and 309 patients with cTn-I <1.0 ng/mL. All cTn-I measurements were made with the Dade Stratus II analyzer. We determined the adjusted 1-year risk of nonfatal MI or death from coronary heart disease (CHD death) in each group by using Cox proportional hazards models.

RESULTS

Among patients with cTn-I elevations between 1.0 and 3.0 ng/mL, 6 (11%) had a nonfatal MI or CHD death at 1 year compared with 12 (4%) patients in the cTn-I <1.0 ng/mL group [hazard ratio (HR), 3.5; 95% CI, 1.4 to 8.8]. After adjusting for baseline clinical characteristics, cTn-I levels between 1.0 and 3.0 ng/mL remained strongly associated with nonfatal MI or CHD death (adjusted HR, 3.4; 95% CI, 1.3 to 9.4). This association persisted even in the 215 patients who presented without chest pain (adjusted HR, 4.3; 95% CI, 1.4 to 13).

CONCLUSIONS

Low-level cTn-I elevations identify a subset of patients at increased risk for future cardiovascular events, even when obtained outside the context of definite ACS or presentation with chest pain.

Cardiac troponin elevations among critically ill patients

PURPOSE OF THE REVIEW

Elevated levels of cardiac troponins, indicative of the presence of cardiac injury, have been reported in critically ill patients. In this review, the incidence, significance, and clinical relevance of elevated troponin levels among this group of patients will be discussed.

RECENT FINDINGS

It has been shown that elevated cardiac troponin levels can be present among critically ill septic patients without evidence of myocardial ischemia. Recent studies show that elevated troponin levels are also present in a diverse group of critically ill patients without sepsis or septic shock. In addition, several but not all studies show that the mortality rate of troponin-positive patients is significantly higher compared with troponin-negative patients.

SUMMARY

Elevated troponin levels are not only present in patients suffering from acute coronary syndromes but can also be present in critically ill patients. Even minor elevations are specific for myocardial injury. However, every elevated troponin level in the critically ill patient should not be rigorously diagnosed or treated as a myocardial infarction.

CARDIAC TROPONIN I LEVELS ARE A RISK FACTOR FOR MORTALITY AND MULTIPLE ORGAN FAILURE IN NONCARDIAC CRITICALLY ILL PATIENTS AND HAVE AN ADDITIVE EFFECT TO THE APACHE II SCORE IN OUTCOME PREDICTION

Cardiac troponin I (cTnI) is a specific marker of myocardial damage used in the diagnosis of acute coronary syndrome (ACS). Recent studies have shown that cTnI levels can also be elevated in patients without ACS, such as in sepsis and trauma patients, and that this is associated with an adverse prognosis. We have evaluated the clinical implications and prognostic significance of serum cTnI levels in noncardiac critically ill patients in a prospective observational study in a general medical intensive care unit at a tertiary-level hospital. A total of 108 consecutive patients without ACS or other cardiac disease was enrolled. Serum cTnI levels were measured on admission using enzyme-linked immunoabsorbant assay kits. Clinical laboratory parameters and outcome were compared between patients with elevated and normal cTnI levels. The prognostic significance of cTnI levels and the Acute Physiology And Chronic Health Evaluation (APACHE) II score was also analyzed. Forty-nine patients (45%) had elevated cTnI levels and 59 (55%) had normal levels. Compared with patients with normal cTnI levels, patients with elevated levels had a higher incidence of new failure of two or more organs, had a lower left ventricular ejection fraction during admission, were more likely to be associated with bacteremia, and had a higher intensive care unit mortality; they also had a significantly shorter survival over a 180-day follow up, before and after stratification by the APACHE II score. Multiple organ failure was the leading cause of mortality in patients with elevated cTnI levels. By multivariate analysis, elevated cTnI levels, a high APACHE II score, and underlying cancer were the three most important independent predictors for a shorter survival. Combination analysis showed a shorter survival in patients with a high APACHE II score plus elevated cTnI levels than in patients with a high APACHE II score or elevated cTnI levels alone. In conclusion, elevated serum cTnI levels is a risk factor for multiple organ failure and mortality in noncardiac critically ill patients, and the cTnI levels and APACHE II score have an additive effect in outcome prediction.

Common causes of troponin elevations in the absence of acute myocardial infarction: incidence and clinical significance

Cardiac troponin is a preferred biomarker of acute myocardial infarction (MI). Unfortunately, elevation of troponin can be detected in a variety of conditions other than acute MI. This review focuses on the incidence and clinical significance of increased troponin in conditions commonly associated with troponin elevations, particularly in those that may resemble acute MI.

Review Article. Cardiac troponins and renal disease

Cardiovascular disease is the most common cause of death in patients with renal failure. Patients with renal failure are at greater risk of atypical presentations of myocardial ischaemia. Traditional markers of myocardial damage are often increased in renal failure in the absence of clinically suspect myocardial ischaemia. The cardiac troponins are specific markers of myocardial injury. Large-scale trials, excluding patients with renal disease, have shown the importance of the cardiac troponins in predicting adverse outcome and in guiding both therapy and intervention in acute coronary syndromes. Cardiac Troponin T and cardiac Troponin I are increased in patients with renal failure and this is likely to represent multifactorial pathology including cardiac dysfunction, left ventricular hypertrophy and cardiac microinfarctions. Increases in serum troponin from baseline, in patients with renal disease with acute coronary syndromes, may represent a poor prognosis. Small studies of patients with renal failure have suggested that elevation of the cardiac troponins is associated with an increased risk of cardiac death.

Troponin I in Patients without Chest Pain

Background: Testing for troponin has important clinical value for patients who present with typical symptoms of acute coronary syndromes (ACS) such as chest pain (CP). Much less is known about the value of troponin testing for patients who present with other symptoms of ACS (anginal equivalent symptoms).

Methods: The utilization and prognostic value of cardiac troponin I (cTnI) were evaluated at a Veterans Affairs Acute Care Facility. Clinical charts of 1184 predominantly male patients, who submitted specimens for initial cTnI testing by AxSYM, were evaluated for demographic data, cardiovascular risk factors, major diseases, and complaints at the time of testing. The endpoint was defined as all-cause death during a 200-day period after initial testing.

Results: Sixty-one percent of cTnI tests were ordered for patients who did not present with CP. Patients presenting with symptoms other than CP did not have significantly lower plasma cTnI than patients with CP. However, patients with symptoms other than CP were rarely diagnosed with ACS unless cTnI was ≥2 μg/L. The mortality during the follow-up period was severalfold higher among patients presenting with symptoms other than CP (CP, 6%; without CP, 22%; P &lt;0.0001, χ2 test). cTnI ≥0.2 μg/L provided significant additional predictive information for patients who presented with anginal equivalent symptoms such as shortness of breath or general weakness.

Conclusion: Patients with anginal equivalent symptoms of ACS and low-positive cTnI are less often diagnosed with ACS and have a higher mortality than patients with CP.