**4. Blunt injury**

**3.2. Cardiac fistulas**

**Figure 3.** Pledgets are used to reinforce the suture line

344 Principles and Practice of Cardiothoracic Surgery

Although hemorrhage and tamponade are the most common injuries seen in penetrating cardiac trauma, cardiac fistulas are another uncommon yet dramatic complication from cardiac trauma (including iatrogenic injuries). Fistulous connections can occur between coronary arteries, aorta, and directly with the cardiac chambers. Patients, if symptomatic, usually present with congestive heart failure and surgical repair is usually required.[10, 11]. Presen‐ tation is variable from acutely after the injury to decades post-injury. Echocardiography and coronary angiography are the cornerstones of diagnosis and necessary to plan surgical repair.

#### **4.1. Background (mechanism, incidence, and pathophysiology)**

Blunt cardiac injury (BCI) is a spectrum of traumatic heart diseases with severity that can range from myocardial contusion and EKG changes to septal rupture and death. Earlier in the century, cardiac contusion or concussion were terms used to diagnose cardiac changes from blunt thoracic trauma. More recently, BCI is the term used to better incorporate and classify

Since blunt cardiac injury is a spectrum of injuries to the heart, a classification scheme was developed to allow clinicians to categorize the types of injury based on outcomes and treatment options. These categories are as follows: 1) BCI with free wall rupture, 2) BCI with septal rupture, 3) BCI with coronary artery rupture, 4) BCI with cardiac failure, 5) BCI with complex arrhythmias, and 6) BCI with minor ECG or cardiac enzyme abnormalities. The American Association for the Surgery of Trauma (AAST) has also published a cardiac injury scale (Table 2) that may help to codify injury for diagnosis and research. Injuries sustained with blunt cardiac injury (BCI) include contusion, ruptures, septal defects, valvular injuries, and coronary artery injuries. Table 3 lists each of these types and the incidence seen from both autopsy and clinical series. Contusion is the most common type of injury with left atrial chamber rupture being least common. Injuries can often occur concomitantly; approximately 20% of injuries with chamber rupture will have another chamber involved. The right heart is the most commonly injured as it is closest to the sternum which is impacted anteriorly by the steering wheel in motor vehicle collisions. Besides having concomitant cardiac injuries, the force needed to cause a BCI will often cause associated injuries such as chest pain, rib fractures, pulmonary contusions, and solid organ injuries; the most common associated injuries that

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http://dx.doi.org/10.5772/55723

The best test for diagnosing blunt cardiac injury has been debated for many years. Cardiac enzymes, radionuclide scans, EKG, cardiac ultrasound and continuous monitoring are some of the major methods that have been investigated. Although cardiac enzymes and radionuclide scans have had many supporters these have not shown reliable predictability in diagnosing blunt cardiac injury and have therefore been left out of the Eastern Association for the Surgery of Trauma (EAST) guidelines (figure 6). Cardiac enzymes, specifically serial troponin meas‐ urements are mentioned in the suggested BCI algorithm by Schultz and Trunkey 2004 (figure 7) as an adjunct to increase the negative predictive value of the normal EKG when you have a patient who has either a history of cardiac disease or increased age. EKG has emerged as the primary screening tool for blunt cardiac injury. There are no pathognomonic findings; however, the presence of a new arrhythmia is a sign that workup needs to be escalated. If the EKG is negative in a young hemodynamically stable patient without a history of cardiac disease there is no further need for workup [12]. If the EKG is abnormal, and the patient has a history of cardiac disease, increased age or hemodynamic instability then continuous telemetry monitoring for 24-48 hours is recommended. Those with hemodynamic instability require continuous monitoring in a surgical ICU. Any arrhythmia may be detected after BCI including sinus tachycardia, supraventricular arrhythmias, ventricular arrhythmias, any type

Although, these patients are likely to have had a FAST exam in the emergency room, it is important to figure out who needs a formal echocardiogram. The key indication is hemody‐ namic instability and a possible diagnosis of blunt cardiac injuiry. Anyone meeting these criteria requires a formal echocardiogram. There has been debate over whether to use trans‐ thoracic or transesophageal echocardiography. The recommendations are that the patient

occur with BCI are listed in Table 5.

of heart block, ST-T changes or Q waves [13].

**4.2. Diagnosis**

#### **Figure 5.**

the myriad of cardiac injuries that result from blunt trauma. BCI is estimated to occur in 20% of motor vehicle collisions and in greater than 75% of thoracic blunt injuries independent of the mechanism. The primary mechanism of injury to the heart is from high-speed motor vehicle collision, but any injury that applies force in the form of kinetic energy to the chest wall and heart can result in a form of BCI. The following mechanisms of injury may result in BCI: direct precordial impact, a crush injury between the sternum and spine, a deceleration injury causing injury from the fixation points of the aorta and vena cava, a hydraulic effect from an intraab‐ dominal injury that sends force to the great vessels and heart, or a crush injury [12].

Since blunt cardiac injury is a spectrum of injuries to the heart, a classification scheme was developed to allow clinicians to categorize the types of injury based on outcomes and treatment options. These categories are as follows: 1) BCI with free wall rupture, 2) BCI with septal rupture, 3) BCI with coronary artery rupture, 4) BCI with cardiac failure, 5) BCI with complex arrhythmias, and 6) BCI with minor ECG or cardiac enzyme abnormalities. The American Association for the Surgery of Trauma (AAST) has also published a cardiac injury scale (Table 2) that may help to codify injury for diagnosis and research. Injuries sustained with blunt cardiac injury (BCI) include contusion, ruptures, septal defects, valvular injuries, and coronary artery injuries. Table 3 lists each of these types and the incidence seen from both autopsy and clinical series. Contusion is the most common type of injury with left atrial chamber rupture being least common. Injuries can often occur concomitantly; approximately 20% of injuries with chamber rupture will have another chamber involved. The right heart is the most commonly injured as it is closest to the sternum which is impacted anteriorly by the steering wheel in motor vehicle collisions. Besides having concomitant cardiac injuries, the force needed to cause a BCI will often cause associated injuries such as chest pain, rib fractures, pulmonary contusions, and solid organ injuries; the most common associated injuries that occur with BCI are listed in Table 5.

#### **4.2. Diagnosis**

the myriad of cardiac injuries that result from blunt trauma. BCI is estimated to occur in 20% of motor vehicle collisions and in greater than 75% of thoracic blunt injuries independent of the mechanism. The primary mechanism of injury to the heart is from high-speed motor vehicle collision, but any injury that applies force in the form of kinetic energy to the chest wall and heart can result in a form of BCI. The following mechanisms of injury may result in BCI: direct precordial impact, a crush injury between the sternum and spine, a deceleration injury causing injury from the fixation points of the aorta and vena cava, a hydraulic effect from an intraab‐

**Figure 5.**

346 Principles and Practice of Cardiothoracic Surgery

dominal injury that sends force to the great vessels and heart, or a crush injury [12].

The best test for diagnosing blunt cardiac injury has been debated for many years. Cardiac enzymes, radionuclide scans, EKG, cardiac ultrasound and continuous monitoring are some of the major methods that have been investigated. Although cardiac enzymes and radionuclide scans have had many supporters these have not shown reliable predictability in diagnosing blunt cardiac injury and have therefore been left out of the Eastern Association for the Surgery of Trauma (EAST) guidelines (figure 6). Cardiac enzymes, specifically serial troponin meas‐ urements are mentioned in the suggested BCI algorithm by Schultz and Trunkey 2004 (figure 7) as an adjunct to increase the negative predictive value of the normal EKG when you have a patient who has either a history of cardiac disease or increased age. EKG has emerged as the primary screening tool for blunt cardiac injury. There are no pathognomonic findings; however, the presence of a new arrhythmia is a sign that workup needs to be escalated. If the EKG is negative in a young hemodynamically stable patient without a history of cardiac disease there is no further need for workup [12]. If the EKG is abnormal, and the patient has a history of cardiac disease, increased age or hemodynamic instability then continuous telemetry monitoring for 24-48 hours is recommended. Those with hemodynamic instability require continuous monitoring in a surgical ICU. Any arrhythmia may be detected after BCI including sinus tachycardia, supraventricular arrhythmias, ventricular arrhythmias, any type of heart block, ST-T changes or Q waves [13].

Although, these patients are likely to have had a FAST exam in the emergency room, it is important to figure out who needs a formal echocardiogram. The key indication is hemody‐ namic instability and a possible diagnosis of blunt cardiac injuiry. Anyone meeting these criteria requires a formal echocardiogram. There has been debate over whether to use trans‐ thoracic or transesophageal echocardiography. The recommendations are that the patient receive the first available study method. If transthoracic echocardiography is used and adequate imaging cannot be obtained, then a transesophageal echocardiogram should be initiated immediately.


\*Advance one grade for multiple wounds to a single chamber or multiple chamber involvement.

**Table 2.** Cardiac Injury Scale

#### **4.3. Management**

Since blunt cardiac injury describes a spectrum of disease states, the treatment depends on the actual problem. Arrhythmia can be managed medically with the caveat that anticoagulation needs to be used cautiously in trauma patients. Hemopericardium can be seen with or without hypotension or tamponade. If hemopericardium is suspected and the patient is stable a subxiphoid pericardial window can be used to verify the hemopericardium. Once a pericardial window is performed, the surgeon must be prepared to proceed with a median sternotomy. If the patient is hypotensive and tamponade is expected then either a subxiphoid pericardial window or a thoracotomy can be performed. As a rule free wall rupture is more common in the atria than the ventricles and more common on the right than the left. This is thought to be

**Cardiac Injury Incidence of injury in autopsy series**

Chamber Rupture

**Table 3.** BCI Patterns of Injury

**Table 4.** Injuries Associated with BCI

**of patients with BCI**

**Associated Injuries Incidence of finding in patients with BCI**

Chest Pain 18% to 92% Rib Fracture 18% to 69% Aortic or great vessel injury 20% to 40% Hemothorax 7% to 64% Pulmonary Contusion 6% to 58% Pneumothorax 7% to 40% Flail Chest 4% to 38% Sternal Fracture 0% to 60% Traumatic Brain Injury 20% to 73% Extremity Injury 20% to 66% Abdominal Solid Organ Injury 5% to 43% Spinal Injury 10% to 20%

Myocardial contusion 60% to 100% 60% to 100%

Right Ventricle 19% to 32% 17% to 32% Right Atrium 10% to 15% 8% to 65% Left Ventricle 5% to 44% 8% to 15% Left Atrium 1% to 7% 0% to 31% Atrial Septal Defect 7% Case reports Valve Injury in BCI 5% Case reports Ventricular Septal Defect 4% Case reports Coronary Artery Injury 3% Case reports

**Incidence of injury in clinical series**

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349

**of patients with BCI**


**Table 3.** BCI Patterns of Injury

receive the first available study method. If transthoracic echocardiography is used and adequate imaging cannot be obtained, then a transesophageal echocardiogram should be

\*Advance one grade for multiple wounds to a single chamber or multiple chamber involvement.

Since blunt cardiac injury describes a spectrum of disease states, the treatment depends on the actual problem. Arrhythmia can be managed medically with the caveat that anticoagulation needs to be used cautiously in trauma patients. Hemopericardium can be seen with or without

initiated immediately.

348 Principles and Practice of Cardiothoracic Surgery

**Table 2.** Cardiac Injury Scale

**4.3. Management**


**Table 4.** Injuries Associated with BCI

hypotension or tamponade. If hemopericardium is suspected and the patient is stable a subxiphoid pericardial window can be used to verify the hemopericardium. Once a pericardial window is performed, the surgeon must be prepared to proceed with a median sternotomy. If the patient is hypotensive and tamponade is expected then either a subxiphoid pericardial window or a thoracotomy can be performed. As a rule free wall rupture is more common in the atria than the ventricles and more common on the right than the left. This is thought to be
