Cardiac troponin I elevation in acute pulmonary embolism is associated with right ventricular dysfunction

Factors underlying elevated troponin I levels following pacemaker primo-implantation

BACKGROUND

Cardiac troponins are routinely used as markers of myocardial damage. Originally, they were only intended for use in diagnosing acute coronary syndromes; however, we now know that raised serum troponin levels are not always caused by ischemia. There are many other clinical conditions that cause damage to cardiomyocytes, leading to raised levels of troponin. However, the specificity of cardiac troponins towards the myocardium is absolute. Our work focuses on mechanical damage to the myocardium and on monitoring the factors that raise the levels of cardiospecific markers after primo-implantation of a pacemaker with an actively fixed electrode.

AIMS

(i) To determine whether the use of a primo-implanted pacemaker with an electrode system with active fixation will raise troponin levels over baseline. (ii) To assess whether troponin I elevation is dependent on procedure complexity.

METHODS

We enrolled 219 consecutive patients indicated for pacemaker primo-implantation; cardiospecific marker values (troponin I, CKMB, myoglobin) were determined before the implantation procedure and again at 6- and 18-h intervals after the procedure. We monitored duration of cardiac skiascopy, number of attempts to place the electrode (active penetration into the tissue) and intervention range (single-chamber versus dual-chamber pacing), and we assessed the clinical data.

RESULTS

The average age of the enrolled patients was 78.2 ± 8.0 years (median age, 80 years); women constituted 45% of the group. We implanted 128 dual-chamber and 91 single-chamber devices with an average skiascopic time of 38.6 ± 22.0 s (median, 33.5 s). Troponin I serum levels increased from an initial 0.03 ± 0.07 μg/L (median, 0.01) to 0.18 ± 0.17 μg/L (median, 0.13) and 0.09 ± 0.18 μg/L (median, 0.04) at 6 and 18 h, respectively. The differences were statistically significant (P < 0.001 or P < 0.001). We confirmed a correlation between troponin increase and duration of skiascopy (P < 0.001). We also demonstrated a correlation between increased troponin I and number of attempts to place a pacemaker electrode (penetration into the tissue) at 6 h (P < 0.001) post-implantation.

CONCLUSION

We detected slightly elevated troponin I levels in patients with primo-implanted pacemakers using electrodes with active fixation. We demonstrated a direct correlation between myocardial damage (number of electrode penetrations into the myocardium) and troponin I elevation, as well as between complexity (severity) of the implantation procedure (indicated by prolonged skiascopy) and raised troponin I. The described phenomenon demonstrates the loss of the diagnostic role of troponin I early after pacemaker primo-implantation in patients with concomitant chest pain.

Cardiac biomarkers in children with congenital heart disease

BACKGROUND

Most congenital heart diseases (CHDs) have specific hemodynamics, including volume and pressure overload, as well as cyanosis and pulmonary hypertension, associated with anatomical abnormalities. Such hemodynamic abnormalities can cause activation of neurohormones, inflammatory cytokines, fibroblasts, and vascular endothelial cells, which in turn contribute to the development of pathologic conditions such as cardiac hypertrophy, fibrosis, and cardiac cell damages and death. Measuring biomarker levels facilitates the prediction of these pathological changes, and provides information about the stress placed on the myocardial cells, the severity of the damage, the responses of neurohumoral factors, and the remodeling of the ventricle. Compared to the ample information on cardiac biomarkers in adult heart diseases, data from children with CHD are still limited.

DATA SOURCES

We reviewed cardiac biomarkers-specifically focusing on troponin as a biomarker of myocardial damage, amino-terminal procollagen type III peptide (PIIIP) as a biomarker of myocardial fibrosis and stromal remodeling, and B-type natriuretic peptide (BNP)/N-terminal proBNP as biomarkers of cardiac load and heart failure, by introducing relevant publications, including our own, on pediatric CHD patients as well as adults.

RESULTS

Levels of highly sensitive troponin I are elevated in patients with atrial septal defects (ASDs) and ventricular septal defects (VSDs). PIIIP levels are also elevated in patients with ASD, VSD, pulmonary stenosis, and Tetralogy of Fallot. Measurement of BNP and N-terminal proBNP levels shows good correlation with heart failure score in children.

CONCLUSIONS

In the treatment of children with CHD requiring delicate care, it is vital to know the specific degree of myocardial damage and severity of heart failure. Cardiac biomarkers are useful tools for ascertaining the condition of CHDs with ease and are likely to be useful in determining the appropriate care of pediatric cardiology patients.

Submassive pulmonary embolism

Pulmonary embolism (PE) is a common diagnosis in critical care. Depending on the severity of clot burden, the clinical picture ranges from nearly asymptomatic to cardiovascular collapse. The signs and symptoms of PE are nonspecific. The clinician must have a high index of suspicion to make the diagnosis. PE is risk stratified into 3 categories: low-risk, submassive, and massive. Submassive PE remains the most challenging with regard to initial and long-term management. Little consensus exists as to the appropriate tests for risk stratification and therapy. This article reviews the current literature and a suggested approach to these patients.

The prognostic value of undetectable highly sensitive cardiac troponin I in patients with acute pulmonary embolism

BACKGROUND

Elevated cardiac troponin levels have been shown to be associated with adverse outcomes in patients with acute pulmonary embolism (PE). However, few data address the management implications of undetectable cardiac troponin I (cTnI) using a highly sensitive assay. We hypothesized that undetectable cTnI predicts very low in-hospital adverse event rates.

METHODS

In a retrospective cohort study, we classified patients with confirmed acute PE according to cTnI detectability into cTnI+ (≥ 0.012 ng/mL) and cTnI- (< 0.012 ng/mL) groups. The Pulmonary Embolism Severity Index (PESI) was used for clinical risk determination. The primary outcome was a composite of hard events defined as in-hospital death, CPR, or thrombolytic therapy. The secondary outcome was a composite of soft events defined as ICU admission or inferior vena cava filter placement.

RESULTS

Among 298 consecutive patients with confirmed acute PE, 161 (55%) were cTnI+ and 137 (45%) cTnI-. No deaths occurred in the cTnI- group vs nine (6%) in the cTnI+ group (P = .004). No hard events were observed in the cTnI- group vs 15 (9%) in the cTnI+ group (P < .001). Soft events were observed at a lower rate in the cTnI- group (21[15%] vs 69 [43%], P < .001). Patients in the cTnI- group had a higher survival rate free of hard (P = .001) or soft (P < .001) events, irrespective of clinical risk. Furthermore, cTnI provided incremental prognostic value beyond clinical, ECG, and imaging data (P < .001).

CONCLUSIONS

Highly sensitive cTnI assay provides an excellent prognostic negative predictive value; thus, it plays a role in identifying candidates for out-of-hospital treatment of acute PE.

Review article: elevated troponin: diagnostic gold or fool's gold?

Troponin is a highly sensitive biomarker of myocardial injury and has been used extensively in everyday clinical practice in the community as well as in hospitals for the diagnosis of acute myocardial infarction (AMI) and for risk stratification of patients with acute coronary symptoms. Dynamic elevations in biomarkers (troponin) are considered fundamental to the diagnosis of AMI. Unfortunately, many clinical conditions can cause troponin elevation in the absence of myocardial ischaemia, and elevated levels sometimes pose a diagnostic dilemma. In some cases, inappropriate diagnosis of 'AMI' based primarily on a raised troponin can have a deleterious impact on an individual, including on driving, insurance and other medicolegal matters. An incorrect diagnosis of myocardial infarction can also lead to the oversight of serious life-threatening alternative causes of troponin elevation (e.g. pulmonary embolism). This article discusses the role of troponin in our everyday clinical practice in the ED.

Cardiac troponin I for predicting right ventricular dysfunction and intermediate risk in patients with normotensive pulmonary embolism

Background

Right ventricular dysfunction (RVD) and cardiac troponin I (cTnI) are important tools for risk stratification in pulmonary embolism (PE). We investigate the association of RVD and cTnI in normotensive PE patients and calculate a cTnI cut-off level for predicting RVD and submassive PE.

Methods

Clinical, laboratory, radiological and echocardiagraphic data were analysed. Patients were categorised into groups with or without RVD and compared focussing on cTnI. Effectiveness of cTnI for predicting RVD and submassive PE was tested.

Results

One hundred twenty-nine normotensive PE patients, 71 with and 58 without RVD, were included. Patients with RVD were older (75.0 years (61.3/81.0) vs. 66.0 years (57.7/75.1), P = 0.019). cTnI (0.06 ng/ml (0.02/0.23) vs. 0.01 ng/ml (0.00/0.03), P < 0.0001) and D-dimer values (2.00 mg/l (1.08/4.05) vs. 1.23 mg/l (0.76/2.26), P = 0.016) were higher in PE with RVD. cTnI was associated with RVD (OR 3.95; 95 % CI 1.95–8.02, p = 0.00014). AUC for cTnI diagnosing RVD was 0.79, and for submassive PE0.87. Cut-off values for cTnI predicting RVD and submassive PE were 0.01 ng/ml, with a negative predictive value of 73 %. cTnI was positively correlated with age, D-dimer and creatinine.

Conclusions

In normotensive PE patients, cTnI is helpful for risk stratification and excluding RVD. cTnI elevation is correlated with increasing age and reduced kidney function.

A thrombus in transit through a patent foramen ovale

Patent foramen ovale (PFO) is a congenital heart defect that may first be diagnosed in adulthood and has a prevalence of 25% to 30%. Although many patients with PFO are asymptomatic and do not require treatment, paradoxical embolism can cause stroke or myocardial infarction. The authors report an unusual case of PFO with a transversing thrombus in an 80-year-old man. The patient's initial presentation appeared clinically as acute coronary syndrome, but he was subsequently diagnosed with a massive thrombus in transit via a PFO and pulmonary embolus leading to right-sided heart failure.

Benefits of thrombolytics in prolonged cardiac arrest and hypothermia over its bleeding risk

A 52-year-old non-smoking Caucasian male, who was admitted to our emergency room after he was found unconscious in the bathroom, went into cardiac arrest requiring prolonged cardiopulmonary resuscitation (CPR) and hypothermia therapy. Cardiac catheterization showed non-obstructive coronary arteries and further bedside echocardiogram suggested probable pulmonary embolism (PE) as an underlying cause of cardiac arrest. Although thrombolytic therapy is an effective therapy for PE, it is not routinely given during prolonged CPR for its life- threatening bleeding complications. Many reported cases have suggested a beneficial effect of empiric thrombolytic in cardiac arrest, but unrelated to duration of resuscitation and adjuvant treatments that imposes bleeding risk. We suspect that tissue plasminogen activator (tPA) should be promptly given to prolonged cardiac arrest patients, even when bleeding risk is high with the concurrent hypothermia treatment, keeping the benefits over risk strategy. Our patient received thrombolytic, tPA and showed remarkable clinical, physiological and radiographical improvement.

Timing of troponin T measurements in triage of pulmonary embolism patients

Aim

To determine the appropriate timing of cardiac troponin T (cTnT) measurement for the early triage of pulmonary embolism (PE) patients.

Methods

In this single-center prospective study, PE was confirmed in all patients using computed tomography. 104 consecutive patients were divided into three groups (high-risk, intermediate, and low-risk) based on their hemodynamic status and echocardiographic signs of right ventricular dysfunction. cTnT levels were measured on admission and then after 6, 24, 48, and 72 hours with threshold values greater than 0.1 ng/mL.

Results

Intermediate-risk PE patients had higher cTnT levels than low-risk patients already in the first measurement (P = 0.037). Elevated cTnT levels significantly correlated with disease severity after 6 hours (intermediate vs low risk patients, P = 0.016, all three groups, P = 0.009).

Conclusion

In hemodynamically stable patients, increased cTnT level on admission differentiated intermediate from low-risk patients and could be used as an important element for the appropriate triage of patients.

Value of cardiac troponin I for predicting in-hospital occurrence of hypotension in stable patients with acute pulmonary embolism

Although cardiac troponin I (cTnI) elevations during acute pulmonary embolism (PE) are predictive of in-hospital death, it is not clear whether cTnI measurements at emergency department (ED) admission are predictive of the occurrence of hypotension. The study subjects included all consecutive patients with acute PE (diagnosed by chest computed tomography angiography) in the ED between January 2006 and December 2011. All underwent cTnI tests at ED admission and were divided into two groups based on the occurrence of hypotension within 24 h. Of 457 stable patients with acute PE who were admitted to the ED during the study period, 301 patients were included. Within 24 h of hospitalization, 27 (9.0%) developed hypotension. The patients who developed hypotension had a significantly higher mean cTnI concentration than did the remaining patients (1.01 vs. 0.14 ng/mL, P < 0.00). They were also more likely to be treated with thrombolytic therapy and had higher 28-day and 6-month mortality rates. Cardiac TnI elevation (>0.05 ng/mL) at ED admission was a strong predictor of the development of hypotension within 24 h (odds ratio, 8.2; 95% confidence interval, 2.6-26.1; P = 0.00). The sensitivity, specificity, positive predictive value, and negative predictive value of elevated cTnI were 85%, 66%, 20%, and 98%, respectively. This study suggests that a normal cTnI nearly rules out subsequent development of hypotension within 24 h. This may help to select those patients who would benefit most from intensive clinical surveillance and escalated treatment.

Atrial fibrillation-induced cardiac troponin I release

BACKGROUND

Cardiac troponin I (cTnI) is highly specific for myocardial damage and for the diagnosis of acute coronary syndrome. We investigated cTnI utility and predictive value in patients with atrial fibrillation (AF) in the acute setting.

METHOD

We studied 354 consecutive patients with the primary diagnosis of AF and clinical symptoms suggestive of myocardial ischemia presenting to our emergency department. cTnI was obtained on presentation. Patients with ST-segment elevation myocardial infarction were excluded. Coronary angiography was performed in 100 patients.

RESULTS

cTnI was elevated (>0.09 μg/L) in 51 of 354 (15%) patients. The mean cTnI in these patients was 0.37 μg/L (0.09-3.14). In 23 of 100 patients undergoing coronary angiography, cTnI was elevated. Only 6 of these 23 patients (26%) had significant stenosis. In 77 of 100 patients undergoing coronary angiography, cTnI was normal, revealing significant stenosis in 25 patients (33%). The positive predictive value of elevated cTnI for a coronary intervention was 26% and the negative predictive value was 68%. Using multivariate logistic regression, we found that heart rate on presentation, the presence of angina pectoris, left ventricular ejection fraction, serum creatinine, and hemoglobin independently predicted elevated cTnI level.

CONCLUSION

These data are the first to show that AF in the acute setting is frequently associated with cTnI elevations. AF patients with high heart rate and/or angina pectoris often show false elevated cTnI levels. These findings are relevant for clinicians evaluating patients with acute AF and myocardial ischemia symptoms. Appropriate clinical guidelines must be established that also consider AF-related elevations in cTnI.

Significance of serum cardiac troponin I levels in pulmonary embolism

BACKGROUND

Some biomarkers can be helpful in the diagnosis of pulmonary embolism (PE) and determining of severity and prognosis of the disease. In this study, we aimed to analyze the elevated cardiac troponin I (cTnI) levels and its association with electrocardiography (ECG) and transthoracic echocardiography (TTE) findings in patients with PE.

METHODS

Totally 106 patients with suspected PE were included in the study. PE was confirmed in 63 of them, whereas it was excluded in the remaining 43 patients. Levels of cTnI were measured in all patients before the prescription of the anticoagulation therapy.

RESULTS

High cTnI levels were found in 50.8% of patients with PE, and in 11.6% of patients without PE (P<0.001). Sensitivity and specificity of the test for the diagnosis of PE were 50.7%, 88.3% respectively. ECG findings were similar in PE patients having either elevated or normal cTnI levels. Approximately 75% of the PE patients with high cTnI had normal ECG findings; the most common pathological changes seen in ECG were S1Q3T3 pattern (~31%). TTE findings were not found to be distinguishing in the patients with suspected PE and high cTnI levels. Pulmonary hypertension (PHT) was the most common echocardiographic finding (~74%) in patients with PE and elevated cTnI levels. However, there was not a statistically significant difference between TTE findings in PE patients with increased and normal cTnI levels.

CONCLUSIONS

In patients presenting with clinical, electrocardiographic and echocardiographic features suggesting pulmonary embolism, increased serum cTnI levels endorse the diagnosis of severe PE.

The emperor's new clothes: hypersensitivity of the new cardiac isoenzymes

Right ventricular (RV) myocardial infarction (MI) and pulmonary embolism (PE) are commonly recognized as two of the most challenging and vexing entities in clinical practice. When either is considered in a differential diagnosis, they warrant close consideration because of the life-threatening nature of these conditions. Their signs and symptoms overlap and, on rare occasions, they both can be simultaneously present in a single patient. Cardiac troponins are considered reliable markers of myocardial injury and are critical to the diagnosis of acute coronary syndromes. However, they can also be elevated in cases of PE. We herewith present a case of a woman who initially presented with syncope and then subsequently dyspnea. She manifested elevated cardiac isoenzymes, right-sided electrocardiogram abnormalities, and RV hypokinesis on echocardiography. She was initially diagnosed with RV infarct and managed with an interventional cardiology approach. However, her symptom of dyspnea persisted and the patient was eventually diagnosed with PE. Clinicians should entertain the diagnosis of PE in patients with elevated troponin I and evidence of right-sided cardiac compromise.

A soluble guanylate cyclase stimulator, BAY 41-8543, preserves right ventricular function in experimental pulmonary embolism

Pulmonary embolism (PE) increases pulmonary vascular resistance, causing right ventricular (RV) dysfunction, and poor clinical outcome. Present studies test if the soluble guanylate cyclase stimulator BAY 41-8543 reduces pulmonary vascular resistance and protects RV function. Experimental PE was induced in anesthetized, male Sprague-Dawley rats by infusing 25 μm polystyrene microspheres (1.95 million/100 g body wt, right jugular vein) producing moderate PE. Pulmonary artery vascular resistance, estimated as RVPSP/CO, increased 3-fold after 5 h of PE. Treatment with BAY 41-8543 (50 μg/kg, I.V.; given at the time of PE induction) normalized this index by reducing RVPSP and markedly increasing CO, via preservation of heart rate and stroke volume. Ex vivo RV heart function showed minimal changes at 5 h of PE, but decreased significantly after 18 h of PE, including peak systolic pressure (PSP, Control 39 ± 1 mmHg vs. 19 ± 3 PE), +dP/dt (1192 ± 93 mmHg/s vs. 444 ± 64) and -dP/dt (-576 ± 60 mmHg/s vs. -278 ± 40). BAY 41-8543 significantly improved all three indices of RV heart function (PSP 35 ± 3.5, +dP/dt 1129 ± 100, -dP/dt -568 ± 87). Experimental PE produced increased PVR and RV dysfunction, which were ameliorated by treatment with BAY 41-8543. Thus, there is vasodilator reserve in this model of experimental PE that can be exploited to reduce the stress upon the heart and preserve RV contractile function.

Right ventricular responses to massive and submassive pulmonary embolism

It is critically important to quickly recognize and treat acute pulmonary embolism (PE). Submassive and massive PEs are associated with right ventricular (RV) dysfunction and may culminate in RV failure, cardiac arrest, and death. A rapid and coordinated diagnostic and management approach can maximize success and save lives.

Volume overload and pressure overload due to left-to-right shunt-induced myocardial injury. - Evaluation using a highly sensitive cardiac Troponin-I assay in children with congenital heart disease-

BACKGROUND

Cardiac troponin I (cTnI) is currently considered to be the most sensitive and specific biochemical marker of acute coronary syndrome and acute myocardial infarction. However, few reports have described the use of cTnI assays for evaluating abnormal hemodynamic load in children with congenital heart disease (CHD). It was hypothesized that significant hemodynamic overload due to a left-to-right shunt induces myocardial injury.

METHODS AND RESULTS

A highly sensitive cTnI assay was used to measure the serum cTnI levels in 30 children with atrial septal defect (ASD), 32 children with ventricular septal defect (VSD), and 350 healthy children. Cardiac catheterization was performed in the children with ASD and VSD to determine the ratio of pulmonary to systemic blood flow, the ratio of pulmonary to systemic arterial pressure (Pp/Ps), the pulmonary vascular resistance index, and the right and left ventricular end-diastolic volume. Serum cTnI levels in both the ASD and VSD children were significantly higher than those in healthy children (P<0.05 and P<0.01, respectively). Furthermore, serum cTnI levels significantly correlated with Pp/Ps (r=0.745, P<0.001) in VSD children.

CONCLUSIONS

Significant volume and pressure overload due to a left-to-right shunt induce myocardial injury and might eventually cause irreversible myocardial remodeling in children with CHD. The serum cTnI level is a useful biomarker for evaluating myocardial damage associated with pulmonary hypertension in VSD children.

CT signs of right ventricular dysfunction: prognostic role in acute pulmonary embolism

OBJECTIVES

The purpose of this study was to compare the prognostic role of various computed tomography (CT) signs of right ventricular (RV) dysfunction, including 3-dimensional ventricular volume measurements, to predict adverse outcomes in patients with acute pulmonary embolism (PE).

BACKGROUND

Three-dimensional ventricular volume measurements based on chest CT have become feasible for routine clinical application; however, their prognostic role in patients with acute PE has not been assessed.

METHODS

We evaluated 260 patients with acute PE for the following CT signs of RV dysfunction obtained on routine chest CT: abnormal position of the interventricular septum, inferior vena cava contrast reflux, right ventricle diameter (RVD) to left ventricle diameter (LVD) ratio on axial sections and 4-chamber (4-CH) views, and 3-dimensional right ventricle volume (RVV) to left ventricle volume (LVV) ratio. Comorbidities and fatal and nonfatal adverse outcomes according to the MAPPET-3 (Management Strategies and Prognosis in Pulmonary Embolism Trial-3) criteria within 30 days were recorded.

RESULTS

Fifty-seven patients (21.9%) had adverse outcomes, including 20 patients (7.7%) who died within 30 days. An RVD(axial)/LVD(axial) ratio >1.0 was not predictive for adverse outcomes. On multivariate analysis (adjusting for comorbidities), abnormal position of the interventricular septum (hazard ratio [HR]: 2.07; p = 0.007), inferior vena cava contrast reflux (HR: 2.57; p = 0.001), RVD(4-CH)/LVD(4-CH) ratio >1.0 (HR: 2.51; p = 0.009), and RVV/LVV ratio >1.2 (HR: 4.04; p < 0.001) were predictive of adverse outcomes, whereas RVD(4-CH)/LVD(4-CH) ratio >1.0 (HR: 3.68; p = 0.039) and RVV/LVV ratio >1.2 (HR: 6.49; p = 0.005) were predictive of 30-day death.

CONCLUSIONS

Three-dimensional ventricular volume measurement on chest CT is a predictor of early death in patients with acute PE, independent of clinical risk factors and comorbidities. Abnormal position of the interventricular septum, inferior vena cava contrast reflux, and RVD(4-CH)/LVD(4-CH) ratio are predictive of adverse outcomes, whereas RVD(axial)/LVD(axial) ratio >1.0 is not.

Elevated Cardiac Biomarkers With Normal Right Ventricular Size Indicate an Unlikely Diagnosis of Acute Pulmonary Embolism in Stable Patients

The purpose of this investigation is to assess the prevalence of elevated cardiac biomarkers, with or without estimates of right ventricular (RV) size, in stable patients with acute pulmonary embolism (PE). Our hypothesis is that the combination of high levels of cardiac troponin I (cTnI), high creatine kinase isoenzyme MB (CK-MB), and normal size RV are sufficiently uncommon in stable patients with PE to make the diagnosis of PE unlikely. Retrospective review showed a high cTnI plus high CK-MB in 20 (3.4%) of 585 stable patients with acute PE. A high cTnI plus high CK-MB with normal RV size was shown in 5 (1.9%) of 264 patients. In stable patients with such findings, therefore, PE is unlikely and other diagnoses, particularly acute coronary syndrome, should be considered before pursuing a diagnosis of PE.

Troponin elevation in conditions other than acute coronary syndromes

Acute coronary syndromes comprise a large spectrum of clinical conditions ranging from unstable angina pectoris to acute ST-elevation myocardial infarction. Chest pain is usually the major symptom of atherosclerotic heart disease; however, it may be challenging to diagnose correctly, especially in the emergency department, because of the ambiguous way that pain is characterized by some patients. Cardiac troponins are sensitive and specific biomarkers used in the diagnosis of myocardial infarction that are released into the bloodstream when cardiac myocytes are damaged by acute ischemia or any other mechanism. They are the cornerstone for the diagnosis, risk assessment, prognosis, and determination of antithrombotic and revascularization strategies. However, troponin elevation indicates the presence, not the mechanism, of myocardial injury. There are many clinical conditions other than myocardial infarction that cause troponin elevation; thus, the physician should be aware of the wide spectrum of disease states that may result in troponin elevation and have a clear understanding of the related pathophysiology to effectively make a differential diagnosis. This review focuses on causes of troponin elevation other than acute coronary syndromes.

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.

Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association

Venous thromboembolism (VTE) is responsible for the hospitalization of >250 000 Americans annually and represents a significant risk for morbidity and mortality. Despite the publication of evidence-based clinical practice guidelines to aid in the management of VTE in its acute and chronic forms, the clinician is frequently confronted with manifestations of VTE for which data are sparse and optimal management is unclear. In particular, the optimal use of advanced therapies for acute VTE, including thrombolysis and catheter-based therapies, remains uncertain. This report addresses the management of massive and submassive pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT),and chronic thromboembolic pulmonary hypertension (CTEPH). The goal is to provide practical advice to enable the busy clinician to optimize the management of patients with these severe manifestations of VTE. Although this document makes recommendations for management, optimal medical decisions must incorporate other factors, including patient wishes, quality of life, and life expectancy based on age and comorbidities. The appropriateness of these recommendations for a specific patient may vary depending on these factors and will be best judged by the bedside clinician.

[Troponin-I in hemodynamically-stable pulmonary embolism: correlation with echocardiography and computed tomography angiography]

BACKGROUND

Troponin-I (TnI) is a marker of severe pulmonary thromboembolism (PTE) in unselected patients. There are few articles that assess its usefulness in hemodynamically-stable patients.

OBJECTIVES

To assess the correlation between TnI levels and both echocardiographic/radiologic signs of right ventricle (RV) dysfunction or pulmonary hypertension (PH), and the severity of the pulmonary vascular obstruction.

METHODS

We selected patients from a prospective cohort of 103 consecutive patients with PTE and systolic arterial pressure ≥ 90 mmHg. Computed tomography pulmonary angiography (CTPA) and echocardiography were performed in all patients. We performed a post hoc study, analyzing the 68 cases in which TnI was measured, at the discretion of the emergency room physician.

RESULTS

Patients included had a median age of 74 years and 50% were male. The patients with elevated TnI had a differentiated clinical profile, suggestive of more severe PTE. There was a significant correlation between TnI levels and systolic pulmonary artery pressure (r=0.46, P<.001), the CTPA-measured pulmonary artery diameter (r=0.48, P<.001), the CTPA-measured RV diameter (r=0.47, P=.001) and the pulmonary vascular obstruction index (r=0.39, P=.001).

CONCLUSION

The higher levels of TnI in patients with hemodynamically stable PTE predicts the existence of more severe PE in hemodynamically-stable patients. This biomarker could be used in the clinical practice to select those patients who might require more intensive monitoring or additional complementary studies.

Troponin elevation in coronary vs. non-coronary disease

Acute myocardial infarction is defined as myocardial cell death due to prolonged myocardial ischaemia. Cardiac troponins (cTn) are the most sensitive and specific biochemical markers of myocardial injury and with the new high-sensitivity troponin methods very minor damages on the heart muscle can be detected. However, elevated cTn levels indicate cardiac injury, but do not define the cause of the injury. Thus, cTn elevations are common in many disease states and do not necessarily indicate the presence of a thrombotic acute coronary syndrome (ACS). In the clinical work it may be difficult to interpret dynamic changes of troponin in conditions such as stroke, pulmonary embolism, sepsis, acute perimyocarditis, Tako-tsubo, acute heart failure, and tachycardia. There are no guidelines to treat patients with elevated cTn levels and no coronary disease. The current strategy of treatment of patients with elevated troponin and non-acute coronary syndrome involves treating the underlying causes. The aim of this paper is to review data from studies of non-ACS patients with acutely elevated troponin who in clinical practice may be difficult to discriminate from ACS patients.

Acute ECG ST-segment elevation mimicking myocardial infarction in a patient with pulmonary embolism

Pulmonary embolism is a common cardiovascular emergency, but it is still often misdiagnosed due to its unspecific clinical symptoms. Elevated troponin concentrations are associated with greater morbidity and mortality in patients with pulmonary embolism. Right ventricular ischemia due to increased right ventricular afterload is believed to be underlying mechanism of elevated troponin values in acute pulmonary embolism, but a paradoxical coronary artery embolism through opened intra-artrial communication is another possible explanation as shown in our case report.

Serum cardiac troponin I concentration in dogs with precapillary and postcapillary pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) is a disease condition leading to right-sided cardiac hypertrophy and, eventually, right-sided heart failure. Cardiac troponin I (cTnI) is a circulating biomarker of cardiac damage.

HYPOTHESIS

Myocardial damage can occur in dogs with precapillary and postcapillary PH.

ANIMALS

One hundred and thirty-three dogs were examined: 26 healthy controls, 42 dogs with mitral valve disease (MVD) without PH, 48 dogs with pulmonary hypertension associated with mitral valve disease (PH-MVD), and 17 dogs with precapillary PH.

METHODS

Prospective, observational study. Serum cTnI concentration was measured with a commercially available immunoassay and results were compared between groups.

RESULTS

Median cTnI was 0.10 ng/mL (range 0.10-0.17 ng/mL) in healthy dogs. Compared with the healthy population, median serum cTnI concentration was increased in dogs with precapillary PH (0.25 ng/mL; range 0.10-1.9 ng/mL; P < .001) and in dogs with PH-MVD (0.21 ng/mL; range 0.10-2.10 ng/mL; P < .001). Median serum cTnI concentration of dogs with MVD (0.12 ng/mL; range 0.10-1.00 ng/mL) was not significantly different compared with control group and dogs with PH-MVD. In dogs with MVD and PH-MVD, only the subgroup with decompensated PH-MVD had significantly higher cTnI concentration compared with dogs with compensated MVD and PH-MVD. Serum cTnI concentration showed significant modest positive correlations with the calculated pulmonary artery systolic pressure in dogs with PH and some echocardiographic indices in dogs with MVD and PH-MVD.

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum cTnI is high in dogs with either precapillary and postcapillary PH. Myocardial damage in dogs with postcapillary PH is likely the consequence of increased severity of MVD.

Acute cardiac effects of marathon running

We sought to clarify the significance of cardiac dysfunction and to assess its relationship with elevated biomarkers by using cardiovascular magnetic resonance imaging in healthy, middle-aged subjects immediately after they ran 26.2 miles. Cardiac dysfunction and elevated blood markers of myocardial injury have been reported after prolonged strenuous exercise. From 425 volunteers, 13 women and 12 men were randomly selected, provided medical and training history, and underwent baseline cardiopulmonary exercise testing to exhaustion. Blood biomarkers, cardiovascular magnetic resonance imaging, and 24-h ambulatory electrocardiography were performed 4 wk before and immediately after the race. Participants were 38.7+/-9.0 yr old, had baseline peak oxygen consumption of 52.9+/-5.6 ml.kg(-1).min(-1), and completed the marathon in 256.2+/-43.5 min. Cardiac troponin I and B-type natriuretic peptide increased following the race (P=0.001 and P<0.0001, respectively). Cardiovascular magnetic resonance-determined pre- and postmarathon left ventricular ejection fractions were comparable, 57.7+/-4.1% and 58.7+/-4.3%, respectively (P=0.32). Right atrial volume index increased from 46.7+/-14.4 to 57.0+/-14.5 ml/m2 (P<0.0001). Similarly, right ventricular end-systolic volume index increased from 47.4+/-11.2 to 57.0+/-14.6 ml/m2 (P<0.0001) whereas the right ventricular ejection fraction dropped from 53.6+/-7.1 to 45.5+/-8.5% (P<0.0001). There were no morphological changes observed in the left atrium or ventricle or evidence of ischemic injury to any chamber by late gadolinium enhancement. There were no significant arrhythmias. Marathon running causes dilation of the right atrium and right ventricle, reduction of right ventricular ejection fraction, and release of cardiac troponin I and B-type natriuretic peptide but does not appear to result in ischemic injury to any chamber.

Are clinical parameters and biomarkers predictive of severity of acute pulmonary emboli on CTPA?

BACKGROUND

Previous studies have shown that findings of computed tomography pulmonary angiography (CTPA) relate to outcome in pulmonary embolus (PE). These include clot burden as quantified using an obstruction index and markers of pressure overload such as right ventricle to left ventricle size ratio (RV/LV ratio). Little data exists correlating these findings with clinical presentation and biomarkers.

AIM

To explore the link between clinical presentation and biomarkers with CTPA findings.

METHODS

Retrospective case note analysis of consecutive cases presenting to a large teaching hospital. An independent radiologist reviewed CTPAs and clot burden quantified using an obstruction index.

RESULTS

One hundred and seventy cases were identified and notes retrieved in 137 cases. (i)

CLINICAL PRESENTATION

correlation was seen between clot burden and systolic blood pressure (BP) (r = -0.299, P = 0.0006) and heart rate (r = 0.240, P = 0.0056). Median obstruction index was significantly higher in those with a presenting BP <90 mmHg [41.25% (95% CI 30-50) vs. 15% (95% CI 12.5-25), (P = 0.0004)]. Clot burden was significantly higher in patients with temperature of >37.5 degrees C [30% (95% CI 25.0-42.5) vs. 15% (95% CI 12.5-28.3), P = 0.02)] and (ii)Biomarkers: significant correlation between clot burden and D-dimer was seen (r = 0.36, P = 0.0001). Location of thrombus was associated with significant differences in D-dimer level. A subgroup of patients had cardiac biomarkers measured (n = 24). There was a statistically significant correlation between troponin I and clot burden (r = 0.412, P = 0.048) and RV/LV ratio (r = 0.699, P = 0.0013).

DISCUSSION

These findings suggest that clinical parameters and biomarkers have a role in predicting the radiological severity of PE. These data support the need for further studies of risk stratification in patients presenting with acute PE.

Pseudo myocardial infarction - a condition in need to be redefined?

Since the introduction of cardiac plasma troponin measurements, a significant number of patients were seen with chest pain, elevated troponin levels but no significant coronary artery disease. Pulmonary embolism, aortic valve disease, myocarditis, sepsis, trauma, arrythmias, stress cardiomyopathy and dilated cardiomyopathy stand among possible causes for this syndrome. In some cases, myocardial strain could be the mechanism underlying this phenomenon, since it is known that the stimulation of stretch-responsive integrins may lead to the release of cardiac troponin I. In the present text, a case is made in favour of classifying this syndrome, of chest pain with increased values for plasma cardiac troponin, with or without ECG changes, in the absence of definite myocardial infarction or coronary artery disease, as pseudo myocardial infarction (PMI). This constitutes a new definition for a concept with decades, formerly centered on clinical and electrocardiographic changes mimicking infarct. The case is based on the search of scientific truth, on avoidance of unnecessary cardiac examinations, on avoidance of unnecessary drug therapy and on avoidance of unnecessary legal liability. PMI should be seen as a working diagnosis, since a more definitive diagnosis can be reached at all time. It should also be seen as a heterogeneous group of patients - several different diseases and conditions can lead to this phenomenon. But it must certainly not be seen as a benign condition, since published studies point in a totally different direction.

Should thrombolysis have a greater role in the management of pulmonary embolism?

Pulmonary embolism (PE) continues to be associated with significant mortality despite advances in the diagnostic techniques available for its detection. Anticoagulation remains standard treatment in PE although there is a consensus view that 'step-up' to thrombolytic therapy in addition to anticoagulation is indicated in those patients who are systemically shocked at presentation--a group defined as having suffered 'massive pulmonary embolism'. Considerable research has been directed at attempting to identify further groups of patients with PE who are at high risk of morbidity and mortality--notably those who are labelled as having suffered 'sub-massive pulmonary embolism' where this is defined as the presence of right-heart strain in the absence of systemic shock. In particular, the potential benefit of extending thrombolytic therapy to include those patients with sub-massive PE has been the subject of much enquiry and debate. This review examines the evidence for thrombolytic therapy and explores the potential for risk stratification in PE.

The correlation between elevated cardiac troponin I and pulmonary artery obstruction index in ED patients with pulmonary embolism

OBJECTIVES

The aim of this study is to investigate the correlation between cardiac troponin I (cTnI) values and the pulmonary artery obstruction index assessed with spiral computed tomography (CT) scan in emergency department (ED) patients with pulmonary embolism (PE).

METHODS

This is a retrospective cohort study of all 179 ED patients diagnosed with PE between December 2004 and January 2007. Study population consisted of 104 (58.1%) of 179 patients with PE in whom both cTnI was measured and a contemporaneously performed CT scan was available for review. In these patients, the levels of cTnI measured in the ED were correlated with the degree of pulmonary vascular obstruction determined by applying the modified Computed Tomography Obstruction Index to the spiral CT scan performed in the ED.

RESULTS

Troponin values were elevated in 20 (19.2%) of 104 patients (95% confidence interval [CI], 11.6-26.8) with a mean cTnI concentration of 0.38 +/- 0.44 microg/L. Elevated cTnI value had a significant correlation with main pulmonary arteries involvement using the modified Computed Tomography Obstruction Index score (P = .0001). Elevated ED cTnI value had 53.8% (95% CI, 37.6-66) sensitivity and 92.3% (95% CI, 87-96.4) specificity, 70% (95% CI, 49-86) PPV, and 85.7% (95% CI, 80.7-90) NPV for predicting main pulmonary artery obstruction on CT. Increased cTnI values were highly correlated to intensive care unit admission of patients with PE (RR, 12.83; 95% CI, 3.87-42.4).

CONCLUSIONS

Measuring cTnI value might be considered in ED patients who are suspected of having PE. Elevated cTnI should raise the clinician's concern for the possibility of central pulmonary vascular obstruction.