Multimodality Imaging of Right Ventricular Pseudoaneurysm Caused by Blunt Chest Trauma.

Right ventricular pseudoaneurysm is a rare but fatal complication of blunt chest trauma. Different imaging modalities including transthoracic echocardiogram, gated-CT angiography and cardiac MR can provide useful anatomic and functional information that can make the diagnosis and guide management. Surgical treatment is needed to avoid fatal outcome. (Level of Difficulty: Beginner.).

A 66-year-old woman who was an unrestrained driver in a low-speed collision with airbag deployment was admitted to the emergency department after full trauma activation. The vital signs were stable at the time of presentation.

Learning Objectives

To understand the imaging findings in right ventricular pseudoaneurysm.

To review the causes of ventricular pseudoaneurysm.

Past Medical History

The patient had history of depression, but otherwise past medical history was unremarkable for any pertinent disease.

Differential Diagnosis

Owing to chest pain and scattered bilateral rib fractures, the possibility of aortic dissection and aortic injury was raised.

Investigations

Electrocardiography was unremarkable. The patient underwent gated computed tomography (CT) angiography of the chest before and after injection of intravenous contrast to assess for possible aortic injury.

Noncontrast CT showed a small 10 × 9 mm outpouching likely arising from the right ventricular apex (Figure 1A), which demonstrated increased enhancement on the arterial phase of the image (Figure 1B), raising concern for pseudoaneurysm. A small amount of pericardial effusion was also present.

Figure 1

Pseudoaneurysm Arising From the Right Ventricular Apex

(A) Non–contrast-gated computed tomography of the chest shows a focal area of soft tissue density abutting the right ventricular apex (arrow). (B) This shows increased arterial enhancement in the arterial phase of gated computed tomography angiography (arrow).

Cardiac magnetic resonance (CMR) was performed to confirm the presence of pseudoaneurysm. Steady-state free precession imaging again showed small outpouching at the level of right ventricular apex (Figure 2A). Post-contrast first-pass perfusion CMR images (Video 1) showed increased enhancement in the outpouching after contrast injection with a small amount of associated mural thrombus confirming the presence of a pseudoaneurysm communicating with the right ventricular cavity. The patient remained stable, and a next-day follow-up transthoracic echocardiography was performed to assess the myocardial function and possible interval worsening of pericardial effusion. Transthoracic echocardiography showed an increase in pericardial effusion and signs of pericardial tamponade, including absence of respiratory variability in the inferior vena cava blood flow (Figure 3A), as well as significant mitral valve and tricuspid valve inflow variability with respiration (Figures 3B and 3C), raising concern for cardiac tamponade.

Figure 2

Pseudoaneurysm Arising From the Right Ventricular Apex

Steady-state free precession image of the heart at the same level again shows focal iso-intense outpouching from the right ventricular apex (arrow). See Video 1.

Online Video 1

Figure 3

Findings Concerning for Cardiac Tamponade on Transthoracic Echocardiography

(A) Lack of normal respiratory variability (arrows) of the dilated inferior vena cava. Tissue Doppler recording at the level of (B) the mitral valve and (C) the tricuspid valve shows significant inflow variability with respiration.

Pseudoaneurysm on first-pass perfusion CMR. After intravenous contrast injection shows, first-pass perfusion images show increased enhancement in the right ventricle apical outpouching confirming the presence of pseudoaneurysm communicating with the right ventricular cavity. There is also a small amount or mural thrombus.

Management

The patient was transferred to the operating room. Intraoperative transesophageal echocardiography confirmed the presence of cardiac tamponade with right ventricular collapse during diastole. A right apical pseudoaneurysm (Figure 4A) covered with pericardium and a small amount of mural thrombus was detected and resected using primary suture technique. A moderate amount of pericardial effusion was also seen and removed.

Figure 4

Intraoperative and Postoperative Findings

(A) Intraoperative image shows the right apical pseudoaneurysm (thin arrows) with small amount of mural clot (thick arrow). (B) Post-operative computed tomography shows post-surgical changes with suture material at the site of resection (arrow).

Discussion

Blunt chest trauma can lead to various types of cardiac complications such as cardiac contusion, cardiac rupture, or formation of pseudoaneurysm (1). It may result in ventricular arrhythmias, cardiac failure, or cardiac tamponade (1). The exact incidence of cardiac contusion is not known but has been reported to be as high as 15% to 24% when using specific cardiac markers such as troponin I or T (1). Ventricular pseudoaneurysm, which is a contained rupture of the ventricular wall (2) and covered by pericardium, clot, or adhesion (3), is a very uncommon complication of blunt chest trauma (4). Pseudoaneurysms usually occur on the left side, and descriptions of right ventricular pseudoaneurysms are limited to rare case reports (5). Pseudoaneurysm is connected to the ventricle by a small neck (2). This is in contrast to a true ventricular aneurysm, which contains myocardium and has a wider neck at its junction with the ventricle. The most common cause of ventricular pseudoaneurysm is myocardial infarction (4). Less common causes are cardiac surgery, endocarditis, or myocardial biopsy (2).

In addition to electrocardiography, which should be done in all patients with blunt trauma to the chest, specific cardiac markers such as troponin I or T should be checked in patients with blunt chest trauma (1). Further assessment can be done with transthoracic echocardiography or transesophageal echocardiogram, mainly to assess the cardiac function. CT angiography of the chest can be obtained for better assessment of cardiovascular anatomy and, if needed, surgical planning (3). CMR can provide both functional and anatomic information (3).

Without treatment, the risk of rupture of pseudoaneurysm is high (up to 40% at 1 year) (6). Therefore, surgical treatment is the standard management, but percutaneous closure has been described in patients at higher risk for surgical intervention to repair the left 6, 7 or right (2) ventricular pseudoaneurysm.

Follow-Up

Post-operative CT demonstrated the suture material at the level of right ventricular apex (Figure 4B). After the surgery, the patient recovered well, with an uneventful course in the post-operative period and during the follow-ups.

Conclusions

Right ventricular pseudoaneurysm is a rare entity, especially after blunt chest trauma. A multimodal imaging approach can be of value in making a timely diagnosis and treatment to avoid a fatal outcome.