Radiological Case: Inferior Vena Cava Bullet Retrieval

Danesh Bansal, MD; Patrick Hussey, MD; Ignacio Chiong, MD

Disclosures

Appl Radiol. 2019;48(1):48D-48E. 

In This Article

Discussion

Generally, a bullet that penetrates the body travels in a straight line and exits the skin or traps itself within the soft tissues in the area of injury. Uncommonly, bullet emboli can occur when a small-caliber, low-powered missile has only enough kinetic energy to penetrate a single arterial or venous wall and lodge intraluminally. The intravascular foreign body can then migrate intravascularly, influenced by its weight, gravity, vascular hydrostatic pressure, patient positioning, and vascular anatomy.

Bullet embolism is a rare complication of gunshot wounds, occurring in 0.3% of cases.[1] To date, fewer than 200 cases of bullet embolism have been reported in the literature.[2] Approximately 75% of described cases are arterial, which tend to embolize peripherally resulting in ischemia, and 25% are venous, which commonly embolize centrally to the heart or pulmonary artery.[3] Retrograde venous bullet embolism, wherein the bullet migrates peripherally against blood flow due to gravity, is extremely rare, with only 14 reported cases.[3] Most venous bullet emboli are asymptomatic. Nonetheless, complications can ensue including, cardiac valvular injury, endocarditis, venous thrombosis, thrombophlebitis, arrhythmia, and pulmonary emboli.

In our case, retrograde migration led the bullet from the right atrium to the IVC; subsequent antegrade migration resulted in the bullet residing at the inferior cavoatrial junction at the time of retrieval. The to-and-fro nature of the migration was due to a combination of blood flow, gravity, patient position, and negative intrathoracic pressure.

Intravascular bullets are frequently diagnosed when serial imaging evaluations demonstrate a wandering foreign body, as in our patient. Bullet embolism should further be considered in the absence of an exit wound and when location of the bullet on imaging is discordant with its presumed trajectory.

Surgery is generally agreed upon for arterial bullet emboli due to the heightened risk of ischemia. Conversely, the management of venous bullet emboli remains controversial, given that most are asymptomatic. The risks of embolization, vascular injury, ischemia, and infection must be weighed against the risks of extraction. Conservative management has been proposed in asymptomatic patients due to the risks of venous embolectomy. It is important to note, however, that conservative management may lead to complications including cardiac injury, pulmonary emboli, arrhythmias, and central ischemia. Shannon et al specify that the morbidity of a retained projectile is substantial (25%).[4] Therefore, the authors advocate extraction in the acute setting (<6 weeks), as removal utilizing modern techniques has a low complication rate (1-2%).

Anecdotally, open surgical procedures were undertaken if venous bullet extraction was deemed necessary. However, there has been a paradigm shift. The advent of innovative endovascular techniques for bullet retrieval has mitigated the need for open surgery, allowing for decreased length of stay, enhanced safety, and improved cosmesis. Multiple variations of endovascular retrieval of bullet emboli have been reported in the literature.[5–8] In our case, a snare device was successfully utilized to retract the bullet from the IVC into the left common femoral vein.

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