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Management of intracardiac bullet embolisation and review of literature
  1. Peter Nguyen,
  2. Jitsupa Sirinit,
  3. David Milia and
  4. Christopher Stephen Davis
  1. Department of Surgery, Division of Trauma/Acute Care Surgery, Medical College of Wisconsin, Wauwatosa, Wisconsin, USA
  1. Correspondence to Dr Christopher Stephen Davis; chdavis{at}mcw.edu

Abstract

Vascular injury is a common complication in firearm injuries; however, intravascular missile embolism is relatively rare. There are only 38 documented cases of intravascular missile embolisation to the heart. Bullet embolisms are difficult to diagnose even with multiple diagnostic modalities and even once identified, the most optimal choice of surgical management is debated. Our patient presented with a gunshot wound to the right posterior shoulder. Cardiac focused assessment with sonography for trauma, chest X-ray, CT and echocardiogram were performed, showing missile location adjacent to the right ventricle with inconclusive evidence of pericardial injury. Exploratory median sternotomy was performed, revealing intact pericardium and injury to the superior vena cava (SVC) with bullet embolisation to the right ventricle. The patient became temporarily asystolic secondary to haemorrhage from the SVC injury. Cardiac massage was performed, dislodging the missile into the inferior vena cava. A venotomy was performed to retrieve the bullet and vascular injuries were primarily repaired.

  • radiology
  • vascular surgery
  • cardiothoracic surgery
  • resuscitation
  • trauma

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Background

Firearm injuries are common in the USA and rates are 19.5 times higher than other high-income countries.1 Blood vessel injury may also be a common complication; however, the occurrence of an intravascular missile embolism is rare. There have only been 216 cases documented in the English literature over the last 30 years and only 38 cases with embolisation to the heart.2 3 However, some bullet embolisms are difficult to diagnose and remain asymptomatic, thus the true incidence may be much higher.4 5 Even once identified, the most optimal choice of surgical treatment and postoperative management is debated.

Case presentation

A 23-year-old man was presented after a motor vehicle crash and gunshot wound to the right posterior shoulder. He arrived haemodynamically normal with a blood pressure of 112/78 and pulse of 93. The patient had a patent airway, normal breath sounds, and palpable radial and dorsalis pedis pulses bilaterally. However, the patient was unresponsive and subsequently intubated for airway protection. Trauma resuscitation secondary survey demonstrated a single penetrating injury to the right deltoid.

Investigations

The patient received a portable chest X-ray exam at bedside, which showed a right-sided haemopneumothorax with bullet fragments over the right shoulder, axilla and lower left heart border with indeterminant location. Bedside focused assessment with sonography for trauma was negative for peritoneal free fluid or pericardial effusion. CT of the chest, abdomen and pelvis with contrast showed a bullet track trajectory from the right axilla along the anterior chest wall to an indeterminant location at the right ventricular apex (figure 1). The bullet was juxtaposed to the right ventricle, likely localised within the pericardium, myocardium or ventricle itself.

Figure 1

Chest CT in the trauma bay demonstrates the final resting position of the bullet laying immediately adjacent to the right ventricular apex. However, myocardial penetration cannot be excluded due to streak artefact related to the bullet and cardiac motion. Right-sided haemopneumothorax was also noted. Axial (A), coronal (B) and sagittal (C) views are shown.

Transthoracic echocardiogram was performed and showed independent motion of the right ventricle relative to the bullet without pericardial effusion (figure 2). Therefore, it was believed that the bullet likely did not penetrate the myocardium and was possibly in the pericardial fat. However, intraoperative transoesophageal echocardiogram prior to exploratory surgery was also inconclusive for the location of the missile (figure 3).

Figure 2

Transthoracic echocardiogram (TTE) in the surgical intensive care unit demonstrates the bullet adjacent to the apical right ventricular free wall with independent motion of the right ventricle. There was no pericardial effusion noted. Parasternal short axis (A) and apical four (B) views are shown.

Figure 3

Transoesophageal echocardiogram (TOE) in the operating room (OR) demonstrates bullet location in the right ventricle wall close to the right ventricular apex. However, this study was inconclusive for the location of the missile and did not reveal an obvious intravascular bullet. Midoesophageal four chamber (A) and transgastric short axis (B) views are shown.

Differential diagnosis

Our differential diagnoses included direct injury to the pericardium or bullet embolisation from a venous injury. Direct injury to the pericardium was unlikely due to lack of pericardial effusion on echocardiography and clinical exam without overt signs of obstructive shock. Diagnosis of bullet embolism was confirmed with exploratory surgery.

Treatment

The patient had a right-sided chest tube placed in the trauma bay with 1200 mL initial output. He was then admitted to the SICU for further monitoring and workup. After the indeterminate transthoracic echocardiogram, a decision was made to urgently take the patient for a pericardial exploration. An intraoperative transoesophageal echocardiogram prior to incision was also indeterminate. We proceeded with an exploratory median sternotomy. There was no obvious injury to the external surface of the heart, however the bullet contour was palpable in the right ventricle. Immediately thereafter, the patient became profoundly hypotensive and billowing of the right thoracic pleura was noted. A right-sided thoracotomy was performed, which revealed massive haemorrhage. With further exploration, a dime-sized hole was found in the lateral superior vena cava (SVC) with a separate medial wall defect. The patient then became temporarily asystolic, though with haemorrhage control and open cardiac massage, a perfusing rhythm was regained. Interestingly the cardiac massage pushed the bullet out of the heart and into the inferior vena cava where it was successfully retrieved through a venotomy (video 1). The SVC injuries were primarily repaired. The passage route of the bullet through the vasculature and right side of the heart is shown in figure 4. Postoperatively, he was treated with routine supportive postoperative care, such as analgesia, antiemetics and bowel regimen.

Figure 4

This diagram shows the movement of the bullet from entry to venotomy. (1) The bullet entered via a superior vena cava (SVC) injury and embolised anterograde to the right ventricular (RV) apex. (2) The bullet embolised retrograde into the inferior vena cava (IVC) during open cardiac massage. (3) A venotomy was performed over the IVC to remove the bullet. This figure was hand drawn digitally by Peter Nguyen.

Video 1

Outcome and follow-up

The remainder of his hospital course was uneventful. He was successfully extubated on postoperative day 1 and transferred to a floor unit on postoperative day 2. On postoperative day 6, his chest and mediastinal tubes were pulled, a repeat chest X-ray was negative and he was discharged with aspirin therapy for 30 days. He followed up in the clinic 2 weeks and 6 months after surgery and remains doing well.

Discussion

There have been 216 reports of bullet embolisation between 1988 and 2018 in the published English literature.2 These injuries were commonly found in young men with a single gunshot wound to the anterior torso with venous missile emboli more common than arterial missile emboli. Venous missiles can embolise antegrade to the heart, where they most commonly settle in the right ventricle in the majority of these cases.3 Table 1 summarises recent case reports with embolisation to the heart after venous injury, entry vessel, terminating chamber and management. A case report in 2020 showed a similar SVC injury with embolisation to the right ventricle with an initial entry site in the right anterior chest.4 Penetrating injuries to the anterior or posterior chest traversing along the sagittal plane are generally easier to correlate anatomically to underlying critical structures. Our case was especially challenging since the injury occurred lateral to mediastinal structures and tracked along the anterior chest wall.

Table 1

Intracardiac bullet embolism case reports and management

It remains difficult to determine the exact location of intracavitary missiles. Many prior case reports and published literature have similar issues of determining if bullets were within cardiac chambers via injury to the mediastinum or embolism from a vessel. CT scans and echocardiography remain the mainstays of diagnosis, each with their own strengths and weaknesses. CT scans can be performed in a timely manner at most trauma centres, yet there may be insufficient soft tissue detail and image quality can be obscured by metal artefact of the bullet. Echocardiography can quickly assess soft tissue injury; however, this requires a skilled operator and can be difficult in patients with poor visual windows or trapped air from extensive trauma. Generally, independent motion of the missile and heart indicates that the bullet is not located in the myocardium, but rather is either outside or inside of the heart. Presence of haemorrhagic pericardial effusion indicates injury to the heart or surrounding mediastinal structures.

Delayed or missed diagnosis of right-sided intracardiac missiles could have fatal outcomes. They can potentially embolise to cause life-threatening pulmonary embolisms, interfere with cardiac conduction pathways to cause dysrhythmias, erode through cardiac tissue and serve as a nidus for endocarditis. Therefore, it is crucial to determine the precise missile location. For our patient, the ambiguity of bullet location within or adjacent to the right ventricle caused delay in proceeding to the operating room. It is unclear if this delay is associated with the patient’s subsequent intraoperative cardiac arrest. We believe that the patient’s SVC injury was temporarily thrombosed and did not initially haemorrhage given the thrombosis and the low pressure venous system. Had haemorrhage from the SVC injury occurred outside of the operating room this likely would have been catastrophic for the patient.

A literature review by Lundy et al determined hard and soft signs for cardiac missile retrieval.6 Hard indications for bullet embolectomy include cardiac tamponade or significant pericardial effusions, contamination before entry into cardiac chambers, irregularly shaped missile, serial imaging with wandering intracardiac missile, presence of an intracardiac shunt, post-traumatic dysrhythmia, haemodynamically significant valvular abnormality, missile location in the left heart and proximity to vital structure (major coronary artery/vein or conduction system) with concern for future complication. For symptomatic patients, an endovascular approach can be attempted first, then followed by an open exploration. In cases with extensive surrounding damage, an open surgical approach is preferred for haemorrhage control and repair of damaged structures. There is currently insufficient evidence if asymptomatic intracardiac missile emboli should be removed due to potential downstream consequences, such as repeat embolisation, dysrhythmias, erosion or endocarditis.7 Due to the rarity of the injury pattern and limited data, it is unknown how often asymptomatic intracardiac missiles cause future complications. Beyond this, management with antiplatelets, anticoagulants and antibiotics remain highly controversial.

Patient’s perspective

My stay was very welcoming. Everybody on that staff had made me feel more than comfortable. They went above and beyond for me, and it is very much appreciated. I would recommend (Hospital Name) to anybody because I had no issue with any staff at any time and I know they did the most for me. The experience was traumatic for me. I hope for whoever goes through a situation like this has the care from a hospital like I did from (Hospital Name).

Learning points

  • Haemodynamically stable patients with possible bullet embolisms should be worked up with CT and echocardiograms to determine the location of the missile.

  • Missed diagnosis of right-sided intracardiac missiles could lead to downstream pulmonary embolism, dysrhythmias, cardiac tissue erosion and/or endocarditis.

  • Treatment of haemodynamically stable symptomatic bullet embolisms should be attempted endovascularly before open exploration, unless there is extensive surrounding damage.

  • Postoperative management of intracardiac bullet embolectomy with antiplatelets, anticoagulants and antibiotics remain highly controversial with no sufficient data for standard of care guidelines.

Ethics statements

Patient consent for publication

References

Footnotes

  • Contributors PN contributed to literature review, data collection and interpretation, manuscript drafting and manuscript edits. JS contributed to patient care, initial correspondence with the patient, manuscript drafting and manuscript edits. DM contributed to patient care and manuscript edits. CSD contributed to data interpretation, manuscript edits and oversaw the development of the manuscript. All authors have read and approved the final version of the manuscript submitted.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.