1955 Srce i krvni sudovi 2013; 32(3): 192-194 Pregledni rad UKS CSS UDRUŽENJE KARDIOLOGA SRBIJE CardiologY SOCIETY OF SERBIA Cardiac emergencies: Blunt chest trauma George Karatasakis, MD, FESC Onassis Cardiac Surgery Center, Athens, Greece Abstract Blunt chest trauma is considered a major health problem worldwide because of the tremendous incre- ase of the motor vehicle accidents. Any part of the heart or the great vessels can be injured. Hemope- ricardium and myocardial contusion are the most frequent cardiac lesions in patients who survive a motor vehicle accident. Rupture of a cardiac chamber, the aorta, or the coronary arteries is often fatal. Valve ruptures especially of the tricuspid valve carry a better prognosis. Diagnosis is based on troponin and cardiac enzymes measurement, ECG changes, chest X-ray, echocardiography and spiral computed tomography. Management of patients with compromised hemodynamics and progressive deteriora- tion is surgical often on an emergent basis. Key words blunt chest trauma, heart and great vessel injury hest injury may affect any organ situated in the tho- thermore, thoracic aorta damage is involved in 15% of racic cavity including the heart and great vessels. patients dying because of motor vehicle accidents2. This CBlunt mechanisms are more often involved in chest discrepancy, between clinical and autopsy findings, may wounds while penetrating traumas are less frequent. lead to the conclusion that the majority of severe injuries Injuries of the skeletal components of the chest (pec- of the heart and great vessels remain undiagnosed with toral muscles, ribs, clavicles etc.) have a better prognosis, lethal consequences. Rupture of a cardiac chamber, is provided that the broken bones do not penetrate any vi- encountered in 35-65% of autopsies, of patients dying tal organ. Routine clinical and laboratory evaluation, following a cardiac trauma and only in 0.3-0.9% in clinical leads to diagnosis in the majority of cases. series3. This dramatic difference could be decreased with Conversely, injuries of the heart or the great vessels early clinical suspicion of cardiac trauma in motor vehicle represent a diagnostic challenge, because rapid and pre- accident victims. cise diagnosis is required especially in patients with he- Virtually all anatomic components of the heart can be modynamic instability. Significant heart or great vessels damaged. damage is related to compromised prognosis. Blunt trau- 1. The coronary arteries may present with laceration, ma that causes cardiac or aortic rupture usually leads to rupture, dissection or acute thrombosis. death because of massive hemorrhage or cardiogenic 2. The ventricular myocardium may present ruptures shock before the patient reaches the hospital. (free wall or intraventricular septum) contusion or aneu- rysms. Etiology-Frequency 3. Valvular lesions include leaflet or chordal rupture and papillary muscle dysfunction because of myocardial The most common cause of blunt chest trauma in contusion. modern world is motor vehicle accident which accounts 1 4. Injury of the great vessels including rupture, dissec- for up to 80% of such injuries . tion, aneurysm formation, or thrombotic occlusion (5). The widespread use of air bags together with the steady 5. Pericardial injury including hemopericardium, tam- increase of car accidents over the last 60 years (almost ten- ponade, or –in the long term-constrictive pericarditis. fold between 1950-1990) attributed to the establishment 6. Commotio cordis of blunt chest trauma as a major health problem world- wide. It has been estimated that thoracic injury occurs in 12 persons per million population per year. Pathophysiology Interestingly there is an impressive difference be- A sudden violent impact of the chest on a broad sur- tween clinical and autopsy data concerning cardiac inju- face like an inflated airbag may lead to an enormously ries. Clinical reports, on injuries of specific anatomic parts high and sudden rise of the intracardiac pressure and pro- of the heart are rare in the literature and in some instanc- duce a tear to a ventricular or atrial wall3. es only case reports can be found. Conversely autopsy Furthermore abrupt deceleration which often occurs in studies demonstrate that the heart is injured in 20% of motor vehicle accidents produces cardiac ruptures in spe- patients dying as a consequence of a traffic accident. -Fur cific sites, where great vessels are entering the heart. The Corresponding author: George Karatasakis, Onassis Cardiac Surgery Center, 356 Syggrou Ave., ATHENS 17674 GR, [email protected], tel:00302109493165, mob:00306944277294 192 aortic annulus is a characteristic site of rupture in motor Thansthoracic echocardiography should be performed vehicle accidents with abrupt deceleration. The inerzia of in patients exhibiting haemodynamic instability, short- the heart differs from the inerzia of the ascending aorta, ness of breath, hypoventilation or complex arrhythmias. therefore the force applied to the heart is greater than the The development of pericardial effusion or tamponade force applied to the ascending aorta. Because of this differ- can be readily diagnosed by transthoracic echocardiogra- ence the heart moves forward faster than the aorta during phy. Valvular lesions include tears of valve leaflet, affect- abrupt deceleration leading to detachment of the heart ing more often the tricuspid valve because it is located in from the aorta at the site of the annulus. Similar forces are the vicinity of the anterior chest wall and lead to signifi- applied at the aortic ligament and the aortic isthmus6-8. cant tricuspid regurgitation. This condition may occur Another common consequence of blunt chest trauma clinically silent and reveal in a remote time period. Con- is myocardial contusion which occurs as a result of impact versely tears of the aortic cusps usually produce severe and compression of the myocardium on the chest wall. It aortic regurgitation and are often combined with aortic is characterized by localized hemorrhagic areas situated wall injuries or aortic dissection13. within the normal myocardium. Areas of necrosis may also An interesting point is that feasibility of transesopha- coexist. Clinical evidence of contusion can be rhythm dis- geal echocardiography in patients with blunt chest trau- turbances or conduction delays. Myocardial contusion ma is greater than feasibility of tranthoracic echocardiog- should be differentiated from myocardial infarction which raphy in such patients. In a study of 134 patents, feasibil- is usually the consequence of coronary artery dissection or ity of transthoracic echocardiography was only 38% while rupture also complicating blunt chest trauma. These two transesophageal echocardiography was feasible in 98% entities differ in clinical severity, prognosis and natural his- of patients14. In this particular clinical study, myocardial tory. In myocardial contusion regional wall motion abnor- contusion and pericardial effusion were the two most malities are not indicative of a specific coronary artery -ter frequent cardiac lesions complicating blunt chest trauma. ritory. Conversely myocardial infarction due to post-trau- Myocardial contusion and pericardial effusion were found matic coronary artery laceration has a classical distribution to be very common yet in another study which included of regional wall motion abnormalities. Furthermore myo- 117 patients with blunt chest trauma15. Using transesoph- cardial contusion is a transient phenomenon, resolving ageal echocardiography, ECG and CK MB levels, authors usually a few weeks after the cardiac injury9, 10. of that study reported that although patients with cardiac lesion had higher incidence of ECG and CKMB abnormal- Diagnosis of heart and great vessels injury ities, these abnormalities were not enough to depict all in patients with blunt chest trauma patents with cardiac injuries evident on transesophageal echocardiography. The diagnosis of cardiac injury in patients with blunt Spiral computed tomography is important in patients with blunt chest trauma, especially those with suspected chest trauma cannot be based solely on clinical findings, 16 because these patients, often victims of motor vehicle arterial injury . Sensitivity of spiral computed tomogra- accidents, present with a variety of symptoms and signs phy for arterial injuries is 73% and specificity 100%. For related to the accident. lesions of the descending thoracic aorta and its branches, computed tomography is of higher diagnostic value than Obviously all patients with blunt chest trauma would 17 complain for chest pain- when conscious- and are usually transesophageal echocardiography . tachypnoic and tachycardic, because of the pain and the Chest x-ray, ECG, cardiac enzymes and troponin I psychological stress. Evidence of cardiogenic shock can should be obtained in all patients with blunt chest trau- raise the suspicion of cardiac damage. Chest x-rays may ma. Those with ischemic changes on ECG, significant el- show evidence of widened cardiac silhouette which is not evation of the biomarkers, complex arrhythmias, hemo- a specific sign. However enlargement of the upper medi- dynamic instability, or persisting and progressive short- astinum is often related to arterial injury. ness of breath should be placed in intensive care unit and Measurement of cardiac enzymes and troponin I level proceed immediately with transthoracic or transesopha- is often useful, although not entirely specific, in diagnos- geal echocardiography