Traumatic rupture of the aortic valve is an uncommon occurrence in blunt thoracic trauma.1 Symptoms of cardiac injury in trauma are often overlooked because of other distracting injuries, and valvular abnormalities often do not manifest for several weeks to months after the initial injury.2 The treatment of traumatic valvular disease may be complicated by other injuries and require management at tertiary care medical centers. Transport to such a center can be facilitated by cardiopulmonary support using extracorporeal membrane oxygenation (ECMO), which has been shown to be safe for interhospital transfer.3
A 23-year-old man with a medical history significant for pulmonic valve stenosis treated with balloon dilation as a child and a bicuspid aortic valve presented to an outside hospital after a motor vehicle accident. On arrival to the emergency department, his Glasgow coma scale score was 14, his lungs were clear to auscultation, and his blood pressure was stable. He was tachycardic to 140 beats per minute and had an oxygen saturation of 80%, which improved to 96% using a non-rebreather mask. A computed tomography (CT) scan showed bilateral ground-glass opacities consistent with pulmonary contusions and bilateral pelvic hematomas.
His admission laboratories were significant for a blood alcohol level of 89 mg/dl, white blood cell count of 21,000/μl, creatinine of 1.1 mg/dl, and urinalysis with 182 red blood cells per high-powered field. He underwent successful angioembolization of the dorsal artery of the penis associated with his pelvic fracture and was admitted to intensive care unit (ICU) for monitoring. His respiratory status deteriorated, and he was placed on bilevel positive airway pressure at 12/5 cm of water with an FIO2 of 0.8. His arterial blood gas was pH 7.34, PaCO2 48 mm Hg, and PaO2 88 mm Hg. A CT angiogram was negative for pulmonary embolus. On hospital day 3, a transesophageal echocardiogram (TEE), for which he was intubated, showed severe aortic valve insufficiency, a bicuspid aortic valve with flail leaflet, and a dilated pulmonary artery, without aortic aneurysm or dissection. A cardiothoracic surgery consult was obtained for an aortic valve replacement (AVR). However, this was deferred because the patient developed severe acute respiratory distress syndrome (ARDS) in the setting of pneumonia due to gram-positive cocci. He became severely hypoxemic with a nadir PaO2 of 71 mm Hg. A low-volume, low-pressure ventilation protocol was initiated, and neuromuscular blockade and inhaled nitric oxide were added for refractory hypoxemia. Milrinone was initiated for cardiac support. Despite these measures, his oxygenation failed to improve, and on day 10 the hospital requested an ECMO transfer to our institution. Our ECMO transport team was mobilized and the patient was cannulated at the originating hospital with a 23 French venous Biomedicus (Medtronic, Eden Prairie, MN) cannula in the left femoral vein and a 20 French elongated one-piece arterial (Medtronic) cannula in the right internal jugular vein. The extracorporeal circuit consisted of a Rotaflow (Maquet, Rastatt, Germany) centrifugal pump, Quadrox D (Maquet) oxygenator, and Cobe E Pack (Sorin, Arvada, CO) tubing system. Initial extracorporeal blood flow was 5.6 L/min and sweep gas flow was 7.25 L/min, which provided adequate physiologic support for safe transport.
The patient was safely transported to our hospital via ambulance and was admitted to our ICU. A repeat TEE confirmed the diagnosis of severe aortic valve regurgitation from a torn leaflet on the left ventricular outflow tract (Figure 1). The patient was taken emergently to the operating room for tissue AVR. He was successfully weaned from cardiopulmonary bypass; however, he required venovenous ECMO for ongoing hypoxemia. He was re-explored in the immediate postoperative period for a hemothorax and incipient tamponade. Within 1 day of chest closure, the patient’s lung compliance and oxygenation began to improve, and venovenous ECMO support was weaned off 5 days after chest closure. The patient had a prolonged ICU course but was ultimately transferred to our acute care rehabilitation center with a normal mental status. He was discharged home on day 60 fully ambulatory.
This case highlights the complex and multidisciplinary approach required to manage the rare complication of blunt thoracic trauma involving valvular disruption. Although valve replacement was indicated in this patient with severe aortic insufficiency, his clinical picture was confounded by pneumonia and severe ARDS. Each problem, in isolation, can be managed with standard intensive critical care medicine or surgery; however, in combination, they required treatment at a tertiary care center with experience in the management of challenging cardiopulmonary disease. A critical step was safe interhospital transfer to a regional ECMO center with transport capability that is integrated into a specialized care center. Not all hospitals can offer advanced care, given the cost and infrastructure required to run such programs. Regionalization of ECMO centers is an efficient and cost-effective way to provide this care to multiple hospitals.
The configuration of the ECMO circuit involved a calculated decision process. Venovenous ECMO is our standard approach for severe ARDS, and venoarterial ECMO is typically used for cardiac failure, both of which were present in this patient.4,5 However, the use of venoarterial ECMO is a relative contraindication in patients with severe aortic insufficiency, with a high risk of left ventricular distention and congestive heart failure.6,7 Given the risk of exacerbating his aortic insufficiency, we decided to support his oxygenation with venovenous ECMO for transport with plans for emergent AVR at our facility after a confirmatory TEE. Alternatively, we could have vented the left atrium via a trans-septal puncture, placed an Impella (Abiomed, Danvers, MA) across the aortic valve into the left ventricle, or used a percutaneous pulmonary artery vent.6–8 These approaches would have required more time and precluded expedient transfer. We chose a cannulation method with sufficient physiologic support to permit safe ECMO transport with a plan for definitive repair of his traumatic cardiac injury upon arrival. This case demonstrates the feasibility and safety of extending advanced cardiopulmonary care to trauma patients using a well-established regional ECMO center with transport capabilities.
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aortic valve; replacement; extracorporeal membrane oxygenation; trauma; blunt