Pulmonary bullet embolism following cardiac gunshot wound: case report of a bullet that traversed the heart twice

Abstract
Background
Cardiac gunshot wounds with bullet embolism (BE) into the pulmonary artery are rare. Most pulmonary BE follow injuries of peripheral veins without concomitant cardiac injury. Herein, we describe a case of cardiac gunshot injury in which the bullet migrated from right atrium through the inferior vena cava down to right internal iliac vein and back to the left pulmonary artery. Such bullet migration is too rare and unusual and to our knowledge not reported before.

Case presentation
On March 4, 2019, a man of 39 had a bullet injury during celebratory gunfire. He was clinically stable with entrance on right posterior chest but no exit. Chest CT scan showed a bullet in the right atrium. The next day, the bullet migrated to the right pelvis as shown by plain chest and pelvic radiographs. CT angiography 3 weeks afterwards displayed the bullet in the right internal iliac vein. Meanwhile, the patient was asymptomatic, thus discharged home. However, 3 months later, he was readmitted because of chest pain, dyspnea, and sweating. A repeat chest CT scan showed the bullet in the left lower lobe pulmonary artery. Hence, pulmonary BE was suspected and eventually a 0.36 bullet was removed via left thoracotomy.

Conclusions
This is a case of symptomatic venous BE with typical diagnostic criteria (a small low-velocity bullet with inlet but no exit located away from anticipated trajectory with migration proven by serial radiographs). Endovascular removal was preferred but was not available. BE of the heart is exceedingly rare. Hence, diagnosis requires a high degree of clinical awareness.