(1763) Pediatric Extracorporeal Support for Blunt Chest Trauma

Introduction: Cardiac valve injury from blunt chest trauma is rare. The aortic valve is affected most. Mitral valve injuries are even less common but can lead to life-threatening acute mitral regurgitation (MR) if not promptly diagnosed. This case highlights a pediatric patient with severe acute MR following a motor vehicle collision (MVC) who required multiple runs of extracorporeal support.

Description: 18-year-old previously healthy male was admitted to the ICU following a high-speed MVC. His injuries included a femur fracture, rib fractures, pulmonary contusions, and small pneumothoraces. Initial labs had mild troponin elevation that resolved in 24 hrs. During femur fracture repair, he developed refractory hypoxia and was placed on venovenous extracorporeal membrane oxygenation (VV ECMO). He was on VV ECMO for 4 days. Screening echocardiogram (echo) showed normal function and moderate MR. 48 hrs post-decannulation, he required increasing ventilator support with development of pulmonary hemorrhage, vasopressors for hypotension, and low mixed venous oxygen saturations. He was re-cannulated onto VV ECMO. CT chest, repeat echo, and cardiac catheterization were completed. Diagnostics revealed severe MR, a structural abnormality of the inferior-lateral wall beneath the A1-P1 mitral leaflets, likely from trauma, and pulmonary capillary wedge pressure elevated to 30. He underwent mechanical valve replacement. Post-surgery, he was successfully decannulated from ECMO and extubated.

Discussion: Prevalence of traumatic mitral valve injury is extremely low at 0.01% of blunt chest traumas with only few pediatric cases. Traumatic mitral valve injury can result in acute MR which leads to worse outcomes compared to chronic MR as it increases pulmonary pressures and edema secondary to reduced left atrial compliance. Acute MR also causes hypotension by impairing cardiac output. If not promptly diagnosed and treated, traumatic mitral valve MR can necessitate invasive interventions or be fatal. Diagnosing traumatic MR can be difficult as exams, EKGs, and troponin lack sensitivity and specificity. Reasons for hypoxia and hypotension are multifactorial in trauma which can further obscure the diagnosis. A high index of suspicion is necessary for acute MR from mitral valve injury in patients with blunt chest trauma.