Circulating cardiac troponin T in myocardial contusion

Cardiac contusions in the acute care setting: Historical background, evaluation and management

INTRODUCTION

Albeit described since 1763, cardiac contusions is still an under-recognised clinical condition in the acute care setting. This evidence-based review aims to provide an overview of the topic by focusing on etiopathogenesis, classification and clinical presentation of patients with cardiac contusions, as well as on the diagnostic work-up and therapy options available for this subset population in the acute care setting.

METHODS

A targeted research strategy was performed using PubMed, MEDLINE, Embase and Cochrane Central databases up to June 2022. The literature search was conducted using the following keywords (in Title and/or Abstract): ("cardiac" OR "heart" OR "myocardial") AND ("contusion"). All available high-quality resources written in English and containing information on epidemiology, etiopathogenesis, clinical findings, diagnosis and management of cardiac contusions were included in our research.

RESULTS

Biochemical samples of cardiac troponins together with a 12‑lead ECG appear to be sufficient screening tools in hemodynamically stable subjects, while cardiac ultrasound provides a further diagnostic clue for patients with hemodynamic instability or those more likely to have a significant cardiac contusion.

CONCLUSIONS

The management of patients with suspected cardiac contusion remains a challenge in clinical practice. For this kind of patients a comprehensive diagnostic approach and a prompt emergency response are required, taking into consideration the degree of severity and clinical impairment of associated traumatic injuries.

Diagnostic approach for myocardial contusion: a retrospective evaluation of patient data and review of the literature

Purpose

Myocardial contusion can be a life-threatening condition in patients who sustained blunt thoracic trauma. The diagnostic approach remains a subject of debate. The aim of this study was to determine the sensitivity and specificity of echocardiography, electrocardiography, troponins T and I (TnT and TnI), and creatine kinase muscle/brain (CK-MB) for identifying patients with a myocardial contusion following blunt thoracic trauma.

Methods

Sensitivity and specificity were first determined in a 10-year retrospective cohort study and second by a systematic literature review with meta-analysis.

Results

Of the 117 patients in the retrospective study, 44 (38%) were considered positive for myocardial contusion. Chest X-ray, chest CT scan, electrocardiograph, and echocardiography had poor sensitivity (< 15%) but good specificity (≥ 90%). Sensitivity to cardiac biomarkers measured at presentation ranged from 59% for TnT to 77% for hs-TnT, specificity ranged from 63% for CK-MB to 100% for TnT. The systematic literature review yielded 28 studies, with 14.5% out of 7242 patients reported as positive for myocardial contusion. The pooled sensitivity of electrocardiography, troponin I, and CK-MB was between 62 and 71%, versus only 45% for echocardiography and 38% for troponin T. The pooled specificity ranged from 63% for CK-MB to 85% for troponin T and 88% for echocardiography.

Conclusion

The best diagnostic approach for myocardial contusion is a combination of electrocardiography and measurement of cardiac biomarkers. If abnormalities are found, telemonitoring is necessary for the early detection of life-threatening arrhythmias. Chest X-ray and CT scan may show other thoracic injuries but provide no information on myocardial contusion.

Electronic supplementary material

The online version of this article (10.1007/s00068-020-01305-4) contains supplementary material, which is available to authorized users.

Cardiac magnetic resonance imaging in suspected blunt cardiac injury: A prospective, pilot, cohort study

INTRODUCTION

The aim of this study was to evaluate the incidence and severity of blunt cardiac injury (BCI) as determined by cardiac magnetic resonance imaging (CMR), and to compare this to currently used diagnostic methods in severely injured patients.

MATERIALS AND METHODS

We conducted a prospective, pilot cohort study of 42 major trauma patients from July 2013 to Jan 2015. The cohort underwent CMR within 7 days, enrolling 21 patients with evidence of chest injury and an elevated Troponin I compared to 21 patients without chest injury who acted as controls. Major adverse cardiac events (MACE) including ventricular arrhythmia, unexplained hypotension requiring inotropes, or a requirement for cardiac surgery were recorded.

RESULTS

6/21 (28%) patients with chest injuries had abnormal CMR scans, while all 21 control patients had normal scans. CMR abnormalities included myocardial oedema, regional wall motion abnormalities, and myocardial haemorrhage. The left ventricle was the commonest site of injury (5/6), followed by the right ventricle (2/6) and tricuspid valve (1/6). MACE occurred in 5 patients. Sensitivity and specificity values for CMR at predicting MACE were 60% (15-95) and 81% (54-96), which compared favourably with other tests.

CONCLUSION

In this pilot trial, CMR was found to give detailed anatomic information of myocardial injury in patients with suspected BCI, and may have a role in the diagnosis and management of patients with suspected BCI.

Thoracic trauma: principles of early management

Thoracic trauma remains an important cause of early and late mortality in the injured patient. This review provides an overview of the emergency room management of thoracic trauma, amplifying the approach and principles of Advanced Trauma Life Support. The presentation, pathophysiology, diagnosis and treatment of the 12 most significant thoracic injuries are described. Focusing on emergency room management, and using the concept of the ‘lethal six’ and ‘hidden six,’ appropriate management strategies are detailed.

Cardiac Troponin I is Increased in Patients with Polytrauma and Chest or Head Trauma. Results of A Retrospective Case-Control Study

Background

We performed a retrospective case-control study to assess the values of cardiac troponin I (cTnI) in a large number of patients admitted to the emergency department (ED) with different types of trauma.

Methods

The study population consisted of all patients aged 18 years or older admitted to the local ED with all types of traumas over a 1-year period. Results of cTnI were compared with those of 125 consecutive blood donors and 25 non-cardiac chest pain ED patients.

Results

The final study population consisted of 380 trauma patients, 10 with isolated abdominal trauma, 99 with isolated trauma of the limbs, 49 with isolated chest trauma, 145 with isolated head trauma and 77 with polytrauma. The concentration of cTnI did not differ among the three study populations, but the frequency of measurable values was substantially higher in patients with trauma (63%) than in blood donors and non-cardiac chest pain ED patients (both 20%). The frequency of cTnI values above the 99^th percentile of the reference range was significantly higher in trauma patients (20%) than in blood donors (0%) and noncardiac chest pain ED patients (8%). Increased cTnI values were more frequent after head trauma (21%), chest trauma (27%) and polytrauma (29%) compared to patients with abdominal (0%) or limbs trauma (8%).

Conclusions

These results suggest that the measurement of cardiac troponin may be advisable to identify potential cardiac involvement in trauma patients, especially in those with polytrauma and head or chest trauma.

Troponin T in Patients with Traumatic Chest Injuries with and without Cardiac Involvement: Insights from an Observational Study

BACKGROUND

Serum troponin T (TnT) is a common marker of myocardial injury. However, its implication in the absence of clinical evidence of cardiac reason is not well established.

AIMS

The aim of this study was to identify the implications of positive TnT in traumatic chest injury (TCI) patients regardless of the cardiac involvement.

MATERIALS AND METHODS

We conducted a retrospective analysis of all TCI patients admitted to level 1 trauma center between 2008 and 2011. Patients who underwent TnT testing were divided into two groups: Group 1 (positive TnT) and Group 2 (negative TnT). The two groups were analyzed and compared, and multivariate regression analyses were performed to identify predictors of TnT positivity and mortality.

RESULTS

Out of 993 blunt TCI patients, 19.3% had positive TnT (Group 1). On comparison to Group 2, patients in Group 1 were 5 years younger and more likely to have head, cardiac, hepatic, splenic, and pelvic injuries, in addition to lung contusion. Positive TnT was associated with higher Injury Severity Score (ISS) (P = 0.001), higher chest Abbreviated Injury Score (AIS) (P = 0.001), and longer hospital stay (P = 0.03). In addition, Group 1 patients were more likely to undergo chest tube insertion, exploratory laparotomy, mechanical ventilation, and tracheostomy. Twenty patients had cardiac involvement, and of them 14 had positive TnT. Among 973 patients who showed no evidence of cardiac involvement, 178 had positive TnT (18.3%). There were 104 deaths (60% in Group 1). On multivariate regression analysis, the predictors of hospital mortality were positive TnT, head injury, and high ISS, whereas, the predictors of TnT positivity were cardiac, hepatic, and pelvic injuries; higher ISS; and age.

CONCLUSIONS

Positive TnT in blunt TCI patients is a common challenge, particularly in polytrauma cases. Patients with positive TnT tend to have the worst outcome even in the absence of clinical evidence of acute cardiac involvement. Positive TnT is also a reflection of the severity of chest or extrathoracic injuries; however, further prospective studies are warranted.

Efficacy of cardiac magnetic resonance for the qualitative diagnosis of blunt cardiac injury

Case

A 47-year-old man was admitted after a car collision in shock with cardiac tamponade. After his circulation was stabilized by pericardial drainage, we treated him conservatively. Abnormal laboratory data and initial electrocardiogram (ECG) were suggestive of myocardial injury. However, echocardiography and cardiac computed tomography could not reveal the cause of the tamponade or the site of cardiac injury. ECG-gated cardiac magnetic resonance images were acquired.

Outcome

The cardiac magnetic resonance black-blood T2-weighted images showed hyperintense signals in the interventricular septum, whereas the late gadolinium enhancement images showed no enhancement in this region. We could accurately diagnose cardiac contusion of the anteroseptal area, which would explain the initial ECG abnormality seen in this patient.

Conclusion

Cardiac magnetic resonance imaging may be especially useful in the evaluation of non-operative management of blunt cardiac injury and could explain the initial ECG abnormality seen in our patient.

Cardiac trauma during teenage years

The spectrum of blunt cardiac trauma ranges from asymptomatic myocardial contusion to fatal cardiac arrhythmias and/or cardiac rupture. Although cardiac rupture is common in fatal traffic accidents, these patients rarely reach hospital care. Insignificant blunt cardiac injury during sports may cause fatal arrhythmia in teens. Penetrating cardiac trauma is fairly common in the United States, encountered frequently in major urban centers. Most cases are dead at the scene and never reach hospital. The incidence of cardiac sequelae in survivors is high, and these patients should be evaluated with early and late echocardiography to detect anatomic or functional cardiac involvement.

Initial management and resuscitation of severe chest trauma

Severe chest trauma, blunt or penetrating, is responsible for up to 25% of traumatic deaths in North America. Respiratory compromise is the most frequent dramatic presentation in blunt trauma, while injuries to the heart and great vessels pose the greatest risk of immediate death following penetrating trauma. More than 80% of patients will be managed with interventions that can be performed in the emergency department. This article reviews the presentation, diagnosis, and management of the most important thoracic injuries. A structured approach to the acutely unstable patient is proposed to guide resuscitation decisions.

Anaesthetic and critical care management of thoracic injuries

Thoracic wounding has been a relatively common presentation of military wounds throughout modern conflict. When civilian casualties are included the incidence has remained constant at around 10%, although the frequency and severity of wounds to combatants has been altered by modern body armour. Whilst thoracic injury has a high initial mortality on the battlefield, those surviving to reach hospital frequently have injuries that only require simple management. In addition to penetrating ballistic injury, blunt chest trauma frequently occurs on operations as a result of road traffic collisions or tertiary blast injury. The physiological impact of thoracic wounds, however, is often great and survivors often require intensive care management and, where available, complex strategies to ensure oxygenation and carbon dioxide removal. This review examines the incidence and patterns of thoracic trauma and looks at therapeutic options for managing these complex cases.

[Cardiac biomarkers for diagnosis of myocardial infarction]

Diagnosis of postoperative myocardial infarction is often difficult, based on tools with a low sensitivity (clinical symptoms, EKG), or with a low specifity (old biomarkers, echocardiographic abnormalities) or inadequate for clinical practice (scintigraphy). Since 1995, clinicians may use more cardiospecific markers (troponin) allowing to modify strategy for postoperative myocardial infarction diagnosis. The aim of this review is to resume such an attitude.

Transient electrocardiographic abnormalities following blunt chest trauma in a child

Blunt cardiac injury may occur in patients after suffering nonpenetrating trauma of the chest. It encompasses a wide spectrum of cardiac injury with varied severity and clinical presentation. Electrocardiographic abnormalities are frequently encountered. This article presents a case of a child who presented with complete right bundle branch block on the initial ECG at the emergency department. She suffered blunt chest trauma during a horseback riding accident. She was admitted for cardiac monitoring. The electrocardiographic abnormalities resolved within 12 hours. No signs of myocardial injury were found on repeat serum troponin measurement and echocardiography. The natural history of ECG abnormalities in the pediatric age group following blunt chest trauma is limited. Although a complete right bundle branch block may be transient in adult patients, this has not been previously reported in a children. Significant ECG abnormalities can be encountered in children following blunt chest trauma. Although a complete RBBB can be associated with severe injury to the RV, it can also occur with minor injury.

Present and Future Biochemical Markers for Detection of Acute Coronary Syndrome

The use of biochemical markers in the diagnosis and management of patients with acute coronary syndrome has increased continually in recent decades. The development of highly sensitive and cardiac-specific troponin assays has changed the view on diagnosis of myocardial infarction and also extended the role of biochemical markers of necrosis into risk stratification and guidance for treatment. The consensus definition of myocardial infarction places increased emphasis on cardiac marker testing, with cardiac troponin replacing creatine kinase MB as the "gold standard" for diagnosis of myocardial infarction. Along with advances in the use of more cardiac-specific markers of myocardial necrosis, biochemical markers that are involved in the progression of atherosclerotic plaques to the vulnerable state or that signal the presence of vulnerable plaques have recently been identified. These markers have variable abilities to predict the risk of an individual for acute coronary syndrome. The aim of this review is to provide an overview of the well-established markers of myocardial necrosis, with a special focus on cardiac troponin I, together with a summary of some of the potential future markers of inflammation, plaque instability, and ischemia.

Tako-tsubo-like left ventricular dysfunction with ST-segment elevation after central spinal cord injury: a case report

The etiology of a novel cardiac syndrome called "tako-tsubo" cardiomyopathy, otherwise known as "acute onset and reversible left ventricular apical wall motion abnormality (ballooning)," is very similar to that of acute myocardial infarction; however, it may also be associated with emotional or physical stress. We report a case of tako-tsubo-like left ventricular dysfunction with ST-segment elevation after trauma. A 69-year-old man was transferred to our hospital after a fall in which he injured his back. He was diagnosed with a central spinal cord injury and was admitted to our Intensive Care Unit. He complained of a sudden chest pain 12 h after the injury. ST-segment elevation was observed on the electrocardiographic monitor, and subsequent 12-lead electrocardiogram demonstrated ST-segment elevation in leads V(2) through V(5). We considered acute myocardial infarction or cardiac contusion to be the cause of this event; therefore, an emergency coronary angiography was performed. However, the angiography revealed no significant coronary artery stenosis. Furthermore, left ventriculography demonstrated severe hypokinesis of the left ventricular apical region, consistent with tako-tsubo-like left ventricular dysfunction. The patient's cardiac function improved gradually, and he was discharged from our hospital on the 18(th) day after admission. Physicians should recognize the syndrome of tako-tsubo-like left ventricular dysfunction, which may result from traumatic stress or chest injury.

Anesthetic management of thoracic trauma

PURPOSE OF REVIEW

Trauma remains a leading cause of death across all age groups. Thoracic injury is a contributing cause in approximately half of these. Despite being potentially life threatening, most thoracic trauma is managed nonoperatively or with an intercostal catheter. Only 10% of thoracic trauma patients will require emergency thoracotomy. Many more will undergo emergency or urgent surgical intervention for coexisting injuries. Thoracic injuries are dynamic. It is crucial for the anesthesiologist to continually reassess the patient, so that the manifestations of evolving injuries may be detected as early as possible and appropriate management decisions made. Up-to-date knowledge of injury patterns, mechanisms, pathophysiology, and operative and nonoperative management will facilitate optimal management of these patients.

RECENT FINDINGS

There is recent literature discussing the surgical, anesthetic and critical care management of a range of thoracic injuries resulting from either blunt or penetrating trauma.

SUMMARY

Initial resuscitation and surgical management of patients with thoracic trauma continue to evolve. Improvements in prehospital care and diagnostic techniques as well as development of minimally invasive interventions mean that the anesthesiologist may be required to provide care to unstable patients in an expanded range of scenarios and environments.

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.

Atrial Septal Rupture, Flail Tricuspid Valve, and Complete Heart Block Due to Nonpenetrating Chest Trauma

This is a report of a patient with an atrial septal defect with right-to-left shunting, flail tricuspid valve, and complete heart block secondary to blunt chest trauma after a motor vehicle accident. The patient surgically repaired with pericardial recreation of atrial septum, bioprosthetic tricuspid valve replacement, and pacemaker insertion. The patient had minimal problems during the hospital course and subsequently made a full postsurgical recovery.

Diverse morphological lesions and serious arrhythmias with hemodynamic insults occur in the early myocardial contusion due to blunt impact in dogs

To investigate the morphology and hemodynamics of the early myocardial contusion, an animal model of cardiac contusion was established by impact to the precordial region at sternum at velocity of 10.0m/s with a mechanical elastic-cord propelled impactor in 19 dogs. The electrocardiogram and both the left and right intra-ventricular pressures were recorded continuously throughout the experiment. Histological and immunohistochemical examinations of myoglobin, creatine kinase-MB and fibrinogen were conducted. At the moment of impact, abrupt over-pressures within the left and right ventricles occurred with concomitant serious arrhythmias followed by variety of cardiac conduction disorders and depressed left and right ventricular systolic pressures during the observation times. Histologically, lesions of myocardial contusions were identified at subepicardial, myocardial or subendocardial layer as interstitial hemorrhage, disruption or coagulative necrosis as well as contraction band necrosis of the muscle fibers, which might be categorized into the hemorrhagic, necrotized and mixed forms. The three forms of lesions were found to exist independently, or co-existed in a heart. However, severity of the lesions varied greatly with different parts even within a heart. Intravascular thromboses were occasionally discovered post-impact. Immunohistochemically, loss of myoglobin and creatine kinase-MB from cardiac cells, and accumulation of fibrinogen at the cell membranes were detected 5min post-impact. The intracellular accumulation of fibrinogen increased with extension of post-impact intervals. Our results indicate that diverse morphological lesions concomitant with hemodynamic compromise and serious, even fatal arrhythmias occur in the early myocardial contusion, and intravascular thromboses are occasionally produced, suggesting that traumatic myocardial ischemic lesion may be induced due to blunt impact to the precordial region.

Dosage des isoformes cardiaques des troponines T ou I : intérêt en cardiologie et en anesthésie–réanimation

Measurement of cardiac troponin I or T in serum (highly specific for the myocardium) have replaced classical markers, such as creatine kinase MB. Cardiac troponins are preferred markers because of their high specificity and sensitivity. This had led to modifications of the original World Health Organization criteria for acute myocardial infarction. Furthermore, the place of the troponins as superior markers of subsequent cardiac risk in acute coronary syndrome has now become firmly established, for both diagnostic and risk stratification purposes. The use of C-reactive protein and/or other inflammatory biomarkers may add independent information in this context. After non cardiac surgery, the total cardiospecificity of cardiac troponins explains why other biomarkers of necrosis should no longer be used. Recent studies suggest that any elevation of troponin in the postoperative period is indicative of increased risk of long-term cardiac complications. This prognostic value has been previously demonstrated in other clinical settings such as invasive coronary intervention (surgical myocardial revascularization and percutaneous coronary intervention) and after heart valve surgery. Increases of troponin indicate cardiac damage, whatever the mechanism (ischemic or not). Other causes of cardiac injury include: pulmonary embolism, myocarditis, pericarditis, congestive heart failure, septic shock, myocardial contusion. In most cases, elevation of troponins has been shown to be associated with a bad outcome.

The relevance of the detection of troponins to the forensic diagnosis of cardiac contusion

The forensic diagnosis of cardiac contusion has hitherto been based mainly on anamnesis, concomitant thoracic injuries and the detection of macroscopic changes to the heart. Parallel histological and serological investigations of the heart-specific troponins have been conducted with varying results. This paper aims to show whether heart-specific troponins are suitable as a means of securing the diagnosis in proven cases of cardiac contusion and of determining which of the three heart-specific troponins cTnT, cTnI and cTnC are most significant in serology and histology for postmortem diagnosis. In the study, 25 cases of known cardiac contusion and 11 controls without vital myocardial trauma taken from autopsy material were prospectively investigated. Investigation of the venous serum revealed significant differences in the concentrations of the case and control groups for troponin T (mean value 5.5056 versus 0.4982; p=0.014), for troponin C (mean value 263.9280 versus 68.5640; p=0.001) and for troponin I (mean value 1404.0560 versus 36.1650; p=0.003). In histology there are also significantly different depletions between the groups investigated (cTnT: p=0.002; cTnC: p=0.003; cTnI: p<0.001) taking into account the autolysis time.

Reference values for cardiac troponins T and I in healthy neonates

OBJECTIVES

Cardiac troponins T (cTnT) and I (cTnI) are the most sensitive biochemical parameters in the detection of myocardial damage. In neonates, in utero exposure to tocolytic therapy results in detectable values of cardiac troponins after delivery. Additionally, some preliminary results suggest that the upper reference limits for healthy newborns are higher than those for adults but definitive reference limits for newborns are not available. Our objective was to determine those limits.

DESIGN AND METHODS

In this study we investigated the distribution of cTnT and cTnI in cord blood of 869 healthy newborns. cTnT was determined with the 3rd generation assay and cTnI with the Dade Behring assay on a Dimension RxL. For data analysis Student's t test and the Mann-Whitney U test were used.

RESULTS

Using the 99th percentile, the upper reference limit in healthy termed newborns was 0.097 microg/l for cTnT and 0.183 microg/l for cTnI. Compared to the adult values, the newborn upper limit was tripled for cTnT and doubled for cTnI. Statistically significant differences were found between males and females for cTnT and between natural childbirth and caesarean section for cTnI.

CONCLUSION

Healthy-termed newborns have a higher upper reference limit for both cTnT and cTnI compared to adults. This circumstance must be taken into account when interpreting slightly "elevated" cTnT and cTnI values in newborns.

Cardiac Troponin I as a Predictor of Arrhythmia and Ventricular Dysfunction in Trauma Patients With Myocardial Contusion

BACKGROUND

Myocardial contusion during blunt chest trauma is common and may lead to potentially fatal cardiac complications. Therefore, it is useful to identify a serum marker reflecting the myocardial damage that can predict risk for cardiac complications. In this study, the authors determined the strength of the association between cardiac troponin I (cTnI) levels and the risk of arrhythmia or the development of left ventricular dysfunction in a cohort of patients with blunt chest trauma.

METHODS AND RESULTS

In 187 multiply injured patients with blunt chest trauma, serial measurements of cTnI, total creatine kinase (CK), and isoenzyme of creatine kinase with muscle and brain subunits (CK-MB) were combined with sequential electrocardigraphic and echocardiographic recordings. The results showed that 63 patients (34%) had myocardial contusion, as defined by positive cTnI levels, of which 47 (25%) were symptomatic and 16 (9%) showed no abnormalities. The remaining 124 patients (66%) displaying negative CTnI levels were asymptomatic during the entire study. Severity of arrhythmia correlated directly with increase in cTnI levels. The levels of cTnI in the symptomatic group remained elevated significantly longer than the levels in the asymptomatic group. The depression of left ventricular ejection fraction was inversely correlated with the increase in cTn levels. The patients whose cTnI levels were below 1.05 microg/L at admission and during the first 6 hours afterward showed no cardiac abnormalities throughout the entire study period

CONCLUSIONS

Levels of cTnI below 1.05 microg/L in asymptomatic patients at admission and within the first 6 hours after admission rule out myocardial injury, whereas positive cTn levels above 1.05 microg/L mandate further cardiologic workup for the detection and management of myocardial injury. Furthermore, the dynamics and peak levels of pathologic cTnI levels allow estimation of arrhythmia risk and left ventricular dysfunction in trauma patients with myocardial contusion.

Isolated myocardial contusion in blunt chest trauma

The objective of this case report was to document a rare case of isolated myocardial contusion in the setting of blunt thoracic trauma. Although demonstrated by electrocardiogram and myocardium-specific enzymes, the trauma had no clinical relevance and the patient was discharged uneventfully from the intensive care unit. The clinical significance of blunt myocardial contusion is then discussed.

Blunt Cardiac Trauma Caused by Fatal Falls From Height: An Autopsy-Based Assessment of the Injury Pattern

BACKGROUND

Falls from height are contributing widely to population morbidity and mortality, especially in urban settings. The presence of blunt cardiac injuries can increase morbidity among these patients, leading even to death. Some clinical studies and case reports have been published on the subject, but a systematic autopsy-based approach to the subject is missing in the literature of recent decades.

METHODS

This study reviewed 61 cases of fatal fall from height that were subjected to a full autopsy at the Institute of Legal Medicine, Hamburg, Germany, from 1998 to 2002. The autopsy protocols and available clinical information were evaluated for assessment of the cardiac injury pattern.

RESULTS

Cardiac injuries were found in 33 cases (54%), all of which involved falls from heights exceeding 6 m. In 16 cases, the cardiac injuries were the cause of death or contributed to the fatal outcome. In five of these cases, the individuals possibly could have recovered from their trauma if their heart injury had been sufficiently diagnosed and adequately treated in time. The most frequent finding was pericardial tearing (45%). Tears caused by stretching of the epicardium in the area wherein the inferior vena cava leads into the right atrium and epicardial hematoma were present in 11 cases (33%). Endocardial tears of the atria were found in six cases (18%), and did not occur during falls from heights lower than 11 m. Transmural tears to the right atrium were present in 10 cases (39%), and to the left atrium in 6 cases (18%). These tears occurred with increasing frequency in relation to greater heights. When the heights were lower than 15 m, these tears were smaller than 1 cm in diameter, but when the heights exceeded 15 m, extensive irregular tears were observed. Sternal fractures were seen in 76% of all cases involving heart injuries. In 16% of these cases, the fractures were multiple. Only 18% of the cases without cardiac injuries had sternal fractures, and none of these was multiple. Thus, the presence of severe sternal fractures can be used as an indicator of possible cardiac trauma.

CONCLUSIONS

A thorough cardiologic diagnosis should always be performed for patients who survive a fall from height. These patients should be transported to a unit capable of performing cardiopulmonary bypass, and explorative thoracotomy should be considered.

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.

Blunt cardiac injury

In summary, the incidence of BCI following blunt thoracic trauma patients has been reported between 20% and 76%, and no gold standard exists to diagnose BCI. Diagnostic tests should be limited to identify those patients who are at risk of developing cardiac complications as a result of BCI. Therapeutic interventions should be directed to treat the complications of BCI. Finally, the prognosis and outcome of BCI patients is encouraging

Effects of cardiac contusion in isolated perfused rat hearts

Myocardial contusion is frequently suspected after blunt chest trauma, but the exact mechanisms of resulting cardiac dysfunction and the time course for enzymatic alterations have not yet been fully understood. Therefore, we investigated pathophysiological aspects of myocardial contusion in a controlled animal model. Male Wistar rat hearts were studied in an isolated perfusion model and were divided into two groups: control (n = 4) and heart contusion (n = 6) groups. The cardiac contusion was produced by a single blow with a weighted pendulum (m = 44 g, height = 20 cm). Functional implications of the contusion were examined in an "isolated perfused heart" model. Troponin 1 concentrations were determined in the perfusate. Cardiac contusion resulted in an increase of coronary perfusion pressure (CPP) of 9 mmHg (P < 0.05, 20 min postcontusion versus baseline and control), followed by a significant increase of left ventricular end-diastolic pressure (LVEDP) of 6 mmHg (P < 0.05, 20 min postcontusion versus baseline and control). Heart contusion was followed by an early increase of troponin 1 (+0.82 ng/mL). The troponin 1 concentration decreased again and, after 20 min, baseline levels were reached. The control group showed no such changes. In this model, high troponin 1 levels after cardiac contusion suggest direct damage to the myocardium. First functional response was shown by the alteration of the coronary perfusion, followed by impaired diastolic function, which persisted even after lowering of the troponin 1 levels.

Normal electrocardiography and serum troponin I levels preclude the presence of clinically significant blunt cardiac injury

BACKGROUND

Uncertainty about the definition and diagnosis of blunt cardiac injury (BCI) leads to unnecessary hospitalization and cost while trying to rule it out. The purpose of this study was to examine whether the combination of two simple tests, electrocardiography (ECG) and serum troponin I (TnI) level, may serve as reliable predictors of BCI or the absence of it.

METHODS

Over a period of 30 months (September 1999-February 2002), 333 consecutive patients with significant blunt thoracic trauma were followed prospectively. Serial ECG and TnI tests were performed routinely and echocardiography was performed selectively. Clinically significant BCI (SigBCI) was defined as the presence of cardiogenic shock, arrhythmias requiring treatment, or posttraumatic structural deficits.

RESULTS

SigBCI was diagnosed in 44 patients (13%). Of 80 patients with abnormal ECG and TnI, 27 (34%) developed SigBCI. Of 131 with normal serial ECG and TnI, none developed SigBCI. Of patients with abnormal ECG only or TnI only, 22% and 7%, respectively, developed SigBCI. The positive and negative predictive values were 29% and 98% for ECG, 21% and 94% for TnI, and 34% and 100% for the combination of ECG and TnI. The admission ECG or TnI was abnormal in 43 of 44 patients with SigBCI. Only one patient had initially normal ECG and TnI and developed abnormalities 8 hours after admission. Forty-one patients without other significant injuries stayed 1 to 3 days in the hospital only to rule out SigBCI and could have been discharged earlier. Besides ECG and TnI, other independent risk factors of SigBCI were an Injury Severity Score > 15, the presence of significant skeletal trauma, and history of cardiac disease.

CONCLUSION

The combination of normal ECG and TnI at admission and 8 hours later rules out the diagnosis of SigBCI. In the absence of other reasons for hospitalization, such patients can be safely discharged.

Cardiac troponins

Cardiac troponins I and T are proteins integral to the function of cardiac muscle. They are very sensitive markers for the detection of myocardial damage, and the ability to assay their serum levels accurately and quickly have revolutionized the concepts of minor myocardial injury and infarction. They are also powerful prognostic indicators of future adverse cardiac events. Limitations, more of troponin T than I, include decreased specificity in renal failure and skeletal muscle disease. Rapid, whole blood assays are now available that can be done at the patient's bedside. This review discusses the cardiac troponins, their biochemistry, the assays for them currently available, and their roles in the evaluation of cardiac disease in the Emergency Department (ED).

Cardiac Trauma (Penetrating and Blunt) and Anesthetic Issues

Patients with blunt or penetrating trauma can require anesthesia and surgery for cardiac injury in the face of noncardiac trauma, or can require anesthesia and surgery for noncardiac injury in the face of cardiac trauma. The true incidence of blunt cardiac trauma is not known, and estimates vary widely with different diagnostic criteria. The diagnosis of traumatic cardiac injury, particularly bluntcardiac injury, may be difficult even with a wealth of available diagnostic tools. Both blunt and penetrating trauma can result is a variety of injuries to cardiac structures. Manifestations of acute traumatic cardiac injury can differ from the clinical manifestations ofsimilar defects in the chronic setting on physical examination, radiography, and in symptomatology. There may be sequelae of traumatic injury which persist, or which may not become apparent for some period of time. Inexpensive, easily-interpreted laboratory criteria for reliably diagnosing cardiac trauma remain. Preexisting cardiacdisease and acute myocardial injury can complicate appropriate resuscitation from massive noncardiac injury. In general, and if unassociated with major noncardiac injuries, patients with cardiac injury be managed with low perioperative mortality.

Acute and long-term clinical significance of myocardial contusion following blunt thoracic trauma: results of a prospective study

BACKGROUND

The clinical significance of myocardial contusion (MC) following blunt thoracic trauma is still unknown. Accordingly, in this prospective study in a regional trauma center we investigated the acute and long-term clinical significance of MC.

METHODS

One-hundred eighteen patients with manifest or suspected blunt thoracic trauma were evaluated for cardiac injury. Initial assessment was based on results of electrocardiographic, echocardiographic, and serial enzyme measurements. A follow-up (FU) assessment conducted at 3 and 12 months, respectively, was performed using electrocardiography, echocardiography, and a bicycle ergometry exercise test.

RESULTS

Of the 118 patients in the total sample, 67 (56.8%) required admission to the surgical intensive care unit (SICU) because of the severity of their noncardiac injuries. Fourteen patients of the total sample (11.8%) were diagnosed with MC and 13 of these (92.9%) belonged to the intensive care admissions, thus representing an incidence of 19.4% in this patient group. During the hospitalization period none of the patients with MC experienced acute cardiac complications. Eighty-six patients (72.0%) were assessed at FU. No new pathologies were found except in one patient. Exercise testing revealed no ECG abnormalities and none of the patients experienced limitations on the bicycle ergometer due to a cardiac cause.

CONCLUSIONS

The incidence of 19.7% of MC in our patients with blunt chest injury requiring intensive care treatment indicates that this condition is frequent in polytraumatized patients. Outcome and prognosis in patients with MC is favorable and, thus, routine cardiac work-up is not indicated. Specific diagnostic and therapeutic measures should be limited to cases where cardiac complications develop.