Clinical significance of radionuclide angiographically-determined abnormalities following acute blunt chest trauma

Accuracy of diagnostic tests in cardiac injury after blunt chest trauma: a systematic review and meta-analysis

INTRODUCTION

The diagnosis of cardiac contusion, caused by blunt chest trauma, remains a challenge due to the non-specific symptoms it causes and the lack of ideal tests to diagnose myocardial damage. A cardiac contusion can be life-threatening if not diagnosed and treated promptly. Several diagnostic tests have been used to evaluate the risk of cardiac complications, but the challenge of identifying patients with contusions nevertheless remains.

AIM OF THE STUDY

To evaluate the accuracy of diagnostic tests for detecting blunt cardiac injury (BCI) and its complications, in patients with severe chest injuries, who are assessed in an emergency department or by any front-line emergency physician.

METHODS

A targeted search strategy was performed using Ovid MEDLINE and Embase databases from 1993 up to October 2022. Data on at least one of the following diagnostic tests: electrocardiogram (ECG), serum creatinine phosphokinase-MB level (CPK-MB), echocardiography (Echo), Cardiac troponin I (cTnI) or Cardiac troponin T (cTnT). Diagnostic tests for cardiac contusion were evaluated for their accuracy in meta-analysis. Heterogeneity was assessed using the I² and the QUADAS-2 tool was used to assess bias of the studies.

RESULTS

This systematic review yielded 51 studies (n = 5,359). The weighted mean incidence of myocardial injuries after sustaining a blunt force trauma stood at 18.3% of cases. Overall weighted mean mortality among patients with blunt cardiac injury was 7.6% (1.4-36.4%). Initial ECG, cTnI, cTnT and transthoracic echocardiography TTE all showed high specificity (> 80%), but lower sensitivity (< 70%). TEE had a specificity of 72.1% (range 35.8-98.2%) and sensitivity of 86.7% (range 40-99.2%) in diagnosing cardiac contusion. CK-MB had the lowest diagnostic odds ratio of 3.598 (95% CI: 1.832-7.068). Normal ECG accompanied by normal cTnI showed a high sensitivity of 85% in ruling out cardiac injuries.

CONCLUSION

Emergency physicians face great challenges in diagnosing cardiac injuries in patients following blunt trauma. In the majority of cases, joint use of ECG and cTnI was a pragmatic and cost-effective approach to rule out cardiac injuries. In addition, TEE may be highly accurate in identifying cardiac injuries in suspected cases.

Diagnosing cardiac contusion: old wisdom and new insights

Cardiac contusion is usually caused by blunt chest trauma and therefore is frequently suspected in patients involved in car or motorcycle accidents. The diagnosis of a myocardial contusion is difficult because of non-specific symptoms and the lack of an ideal test to detect myocardial damage. Cardiac contusion can cause life threatening arrhythmias and cardiac failure. Many diagnostic methods, such as ECG, biochemical cardiac markers, transthoracic and transoesophageal echocardiography, and radionuclide imaging studies, have been investigated to determine their use in predicting such complications. Recently, cardiac troponin I and T were found to be highly sensitive for myocardial injury. Troponin I and T have also proved to be useful in the stratification of patients at risk for complications. Nevertheless, diagnosis of a cardiac contusion and identification of patients at risk remain a challenge. In this review the current diagnostic tests will be discussed. Also, based on these diagnostic tests, a screening strategy containing data from the latest studies is presented, with the intention of detecting patients at risk.

[Role of isotopic imaging in intensive care]

The real place of isotopic imaging in intensive care patients remains still unclear. This review aimed to consider the indications of isotopic imaging for improved diagnosis and therapy and to specify its place among the other techniques of exploration. Pulmonary perfusion and ventilation scintigraphies are valuable for the diagnosis of pulmonary embolism (PE). A "high probability" scintigraphy of the lungs ascertains the diagnosis of PE and allows to start a specific treatment without requiring a pulmonary angiography. This is not the case in the presence of a history of previous PE or if the arguments for a PE are only weak. A normal lung scintigraphy eliminates the diagnosis of a clinically significant PE all the more as an exploration of good quality of the lower limb veins remains negative. In the opposite a "non diagnostic" scintigraphy justifies a pulmonary angiography in intensive care patients. The diagnosis of myocardial contusion is made uneasy as the clinical symptoms, the ECG, the cardiac enzymes and the chest X-ray are only of limited value. Isotopic explorations of the heart could provide additional valuable data or be an alternative for 2 D echocardiography. The comparison of CPK-MB concentrations with a myocardial scintigraphy using thallium 201 is given as being very reliable, with positive and negative predictive values higher than 80%. An exploration restricted to the cardiac ejection fractions is only of limited value. In the future, an improvement will perhaps be obtained with tracers such as MIBI labelled with technetium 99m, which allow the simultaneous assessment of myocardial perfusion and the ventricular ejection fractions as well. The localisation of centres of infection, especially when intra-abdominal, remains difficult in intensive care patients. Isotopic imaging, especially the scintigraphies with labelled polynuclears, could allow in combination with conventional imaging techniques (computed tomography and 2 D echocardiography) to prevent from errors in diagnosis. An array of arguments is essential for ascertaining the presence of an abscess. Scintigraphies with leucocytes labelled with indium 111 or technetium 99m are qualified as having a sensitivity and a specificity greater than 90%. The conventional techniques of measurement of the cerebral blood flow (CBF) using xenon 133 require a special equipment or are invasive. Other cerebral tracers, such as cyclic amines (HMPAO) labelled with technetium 99m and administrable by i.v. route, allow the use of a standard tomo-gamma camera, and could be of help in various pathological conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

A rational screening and treatment strategy based on the electrocardiogram alone for suspected cardiac contusion

The charts of 71 patients admitted to one teaching institution over a 4-year period with a primary or secondary diagnosis of "rule out cardiac contusion" and of another 62 admitted to a second institution with more severe injuries and suspicion of cardiac contusion were reviewed to determine if mortality or morbidity would have occurred if all patients with normal electrocardiograms (EKGs) in the emergency department (ED) were discharged (or admitted to unmonitored beds for other injuries). Only 13 patients developed cardiac problems: two elderly patients died in the ED, while the others experienced arrhythmias or, less commonly, pump failure requiring treatment or observation. All 13 had EKG changes present while still undergoing evaluation in the ED: 11 had a specific problem on arrival, 1 developed a problem while still being evaluated in the ED, and the 13th had what was probably an iatrogenic problem. Importantly, 5 of 12 patients had normal creatine phosphokinase-MB fractions, and 5 of 9 had normal echocardiograms. No patient with a normal EKG had subsequent cardiac problems. Operative intervention for other injuries was necessary in 26 patients overall, and there was no cardiac morbidity. We conclude that had the EKG been used as the sole screening tool, approximately 25% of these patients could have been discharged from the ED without missing problems. In addition, management would have been greatly simplified, and the hospital would have realized substantial savings, both in terms of direct costs and in the freeing of valuable and scarce resources.