Surgical Repair of Right Atrial Wall Rupture after Blunt Chest Trauma

Abstract

Right atrial wall rupture after blunt chest trauma is a catastrophic event associated with high mortality rates. We report the case of a 24-year-old woman who was ejected 40 feet during a motor vehicle accident. Upon presentation, she was awake and alert, with a systolic blood pressure of 100 mmHg. Chest computed tomography disclosed a large pericardial effusion; transthoracic echocardiography confirmed this finding and also found right ventricular diastolic collapse.

A diagnosis of cardiac tamponade with probable cardiac injury was made; the patient was taken to the operating room, where median sternotomy revealed a 1-cm laceration of the right atrial appendage. This lesion was directly repaired with 4-0 polypropylene suture. Her postoperative course was uneventful, and she continued to recover from injuries to the musculoskeletal system.

This case highlights the need for a high degree of suspicion of cardiac injuries after blunt chest trauma. An algorithm is proposed for rapid recognition, diagnosis, and treatment of these lesions.

Right atrial wall rupture after blunt chest trauma is a catastrophic event associated with high mortality rates. Clinical series have indicated a rate of right atrial rupture after blunt trauma that ranges from 8% to 65% in patients with blunt cardiac injury.¹ The first report of successful direct repair of right atrial rupture was published in 1955,² but to this day successful surgical repair and survival of these patients remains uncommon.³ We report the prompt diagnosis and treatment of a right atrial wall rupture in a young woman after a motor vehicle accident.

Case Report

In February 2011, a previously healthy 24-year-old woman was transferred to our hospital after being involved in a car accident in which she was ejected 40 feet from the vehicle. Upon arrival, she was awake, alert, and oriented to person, place, and time. On physical examination, she had a systolic blood pressure of 100 mmHg, ecchymosis surrounding the left orbit and on the anterior chest wall, and deformity of her left shoulder. Cardiovascular evaluation revealed only distant-sounding heart sounds, without hypotension or distended jugular veins. Her abdomen was mildly distended with no peritoneal signs.

Laboratory tests showed a hemoglobin level of 9.2 g/dL, white blood cell count of 25.2 × 10⁹/L, arterial blood gas pH of 7.2, PCO₂ of 33 mmHg, PO₂ of 93 mmHg, bicarbonate of 12.2 mEq/L, base excess of —15 mEq/L, alanine aminotransferase of 304 U/L, aspartate aminotransferase of 604 U/L, creatine kinase of 1,108 U/L, creatine kinase-MB fraction of 14.9 ng/mL, and cardiac troponin of 0.82 ng/mL. Swan-Ganz catheter readings revealed central venous pressure (CVP) of 26 mmHg, pulmonary artery diastolic pressure of 25 mmHg, and pulmonary capillary wedge pressure of 25 mmHg. Cardiac output was 1.8 L/min and the patient's arterial blood gas showed a pH of 7.2.

A chest radiograph showed fractures of the first 4 right ribs and the first and second left ribs. The referring hospital's computed tomographic scan of the chest disclosed a large pericardial effusion and a slight pulmonary contusion (Fig. 1). Transthoracic echocardiography confirmed the pericardial effusion and found a CVP of 24 mmHg, together with right ventricular diastolic collapse (Fig. 2). A diagnosis of cardiac tamponade and probable cardiac injury was made, and the patient was taken to the operating room.

Fig. 1 Computed tomography. A) Coronal and B) axial views disclose pericardial effusion (arrow).

Fig. 2 A transthoracic echocardiogram (2-dimensional apical view) confirms the presence of moderate pericardial effusion, with a central venous pressure of 24 mmHg and right ventricular collapse.

After median sternotomy, the pericardium was seen to be distended with blood. Opening the pericardium enabled the release of several hundred cubic centimeters of blood and clot and resulted in an immediate rise in systolic blood pressure, to 160 mmHg. An actively bleeding 1-cm laceration to the right atrial appendage was directly repaired with a double row of 4-0 polypropylene monofilament sutures (Fig. 3). No other cardiac injuries or bleeding sites were found.

Fig. 3 Intraoperative photograph. The lesion was directly repaired with a double row of 4-0 polypropylene monofilament sutures. No other cardiac or great vessel injuries were found.

The patient's postoperative course was uneventful. When last seen, she continued to recover from injuries to the musculoskeletal system.

Discussion

Cardiovascular injuries are second only to central nervous system injuries as the most frequent cause of death after blunt trauma. Motor vehicle accidents account for over 70% of all cases of blunt cardiac injury.⁴ The rest are attributable to falls, sports injuries, and even to cardiopulmonary resuscitation.⁵ The spectrum of potential injuries to the heart after blunt chest trauma is wide, including myocardial contusion, free wall or septal rupture, valvular disruptions, and injury to the great vessels. In addition, pericardial involvement and dys-rhythmic complications can occur.^6,7 Chamber rupture carries a high mortality index, and most patients do not reach the emergency room.⁸ The National Trauma Data Bank reports that chamber rupture represents 0.041% of all trauma cases and has an overall mortality rate of 89.2%.⁴ The right atrial appendage is the most common site of rupture, probably due to its thin wall.³ The mechanisms of injury include direct mechanical compression by the sternum and indirect effects due to transfer of hydraulic pressure from the abdomen or extremities when compressed.⁹ Clinical features can vary widely due to concomitant injuries. Chest pain is the most common symptom⁶; other physical findings result from cardiac dysfunction and relate, therefore, to the patient's hemodynamic status (for example, systemic hypotension and elevated CVP).¹⁰ Cardiac tamponade from chamber rupture is relatively frequent and is suspected when hypotension, jugular distention, and muffled heart sounds (the Beck triad) are present. In an acute setting, it is life-threatening, leading to a decline in cardiac output secondary to the increased pericardial pressure and ultimately resulting in cardiogenic shock.

In chest trauma patients who present with no evident clinical signs, the diagnosis of blunt cardiac injury is often difficult to make and requires the use of several diagnostic tests.¹⁰ Up to 80% of patients with blunt cardiac injury develop nonspecific changes on electro-cardiography,¹ but normal electrocardiograms have a high negative predictive value for cardiac complications.¹¹ Cardiac enzyme values are commonly measured during diagnostic evaluation. Creatine kinase and its myocardial-band fraction are often elevated in trauma patients and are neither sensitive nor specific for blunt cardiac injury. Cardiac troponins I and T are highly specific to myocardial injury and can be helpful in the screening of blunt cardiac injury; moreover, a normal concentration of troponins is reported to be an indicator of the absence of blunt cardiac injury.^1,10,12 Certainly echocardiography provides direct visualization of the cardiac anatomy and has been shown to be one of the most useful tools for the detection of blunt cardiac injury, cardiac tamponade, and noncardiac injuries as well. Transthoracic echocardiography should be performed promptly in patients who exhibit unexplained hypotension or evidence of cardiac failure.⁹

No diagnostic test is accurate enough, by itself, to confirm or rule out blunt cardiac injury; therefore, we are proposing the use of a diagnostic algorithm that is based on the patient's hemodynamic status (Fig. 4). Patients with chamber rupture and tamponade require emergency cardiac surgical consultation. Pericardiocentesis via the subxiphoid approach under ultrasonic guidance can be useful in the acute setting, because removal of the pericardial fluid produces a dramatic improvement in overall hemodynamics.³ Surgical repair of the defect is the definitive treatment: the standard approach uses a median sternotomy to expose the heart and great vessels, and the rupture usually can be repaired by simple suture under direct compression or after application of a vascular clamp without cardiopulmonary bypass.³

Fig. 4 Proposed algorithm for the evaluation of patients under clinical suspicion of blunt cardiac injury.

BCI = blunt cardiac injury; ECG = electrocardiogram; echo = echocardiogram

In conclusion, our case highlights the need for a high degree of suspicion of cardiac injuries after blunt chest trauma and the importance of prompt diagnosis and treatment of these lesions.