Cardiopulmonary bypass after severe blunt hepatic injury: management of multi-system blunt trauma in an adolescent

Abstract

A 16-year-old adolescent male sustained combined injuries to the tricuspid valve and liver. This injury is exceptional due to the mechanism and the circumstances in which it took place: a flying pumpkin thrown from a sport utility vehicle. An echocardiogram demonstrated a flail chordal apparatus associated with the posterior leaflet of the tricuspid valve, creating substrate for severe tricuspid regurgitation with preserved right heart function. He was treated with non-operative management for the liver injury; he remained hemodynamically stable and was discharged home. He underwent successful repair of the tricuspid valve 17 days following the initial injury necessitating systemic anticoagulation and was discharged home two days later. The patient recovered fully without residual valvular pathology or hepatic sequelae.

Approximately one in four patients admitted to a pediatric Level I trauma center has a traumatic injury of the chest, with high-energy blunt trauma accounting for 83% of those injuries [1]. While pulmonary contusions are the most commonly found thoracic injuries in the hospital setting [2], blunt injury to the heart accounts for both a significant number of pre-hospital deaths and an in-hospital mortality of up to 40% [1]. Blunt cardiac injury occurs most commonly in adolescent males in the street setting (i.e. motor vehicle collisions and pedestrian struck). In more than 50% of cases, blunt cardiac injury is also associated with significant intra-abdominal solid organ injury. The diagnosis of hemodynamically significant cardiac injuries is often delayed due to confounding clinical findings, such as pain and hypovolemia, with associated injuries often being more clinically conspicuous [3].

Concomitant injuries to the myocardium, cardiac valves and liver present a challenging management dilemma. Optimal management of blunt liver injury relies on an intact coagulation cascade, while repair of the cardiac valves is impossible without systemic anticoagulation. In this report, we discuss the presentation, diagnosis, clinical decision-making, and outcomes of this complex injury pattern.

1. Case report

A 16 year old cross-country athlete was walking home on Sunday afternoon from his friend’s house, when an SUV drove toward him. A large pumpkin was thrown from said SUV and struck him in the lower chest and upper abdomen, causing him to fall and briefly lose consciousness. EMS was called by a bystander. He experienced several bouts of emesis following regaining consciousness and was transported to a local hospital via EMT. He was resuscitated according to ATLS protocol, and CT scans of the chest, abdomen and pelvis were obtained which demonstrated a grade III liver laceration and multiple pulmonary contusions (Fig. 1).

Fig. 1.

Selected axial CT image through the upper abdomen at the time of presentation demonstrating a grade III liver laceration.

He was treated non-operatively for his solid organ injury and remained on bed rest. Hematologic studies were stable in the first 48 h. On hospital day #3, he developed orthostatic hypotension and a new heart murmur. Urgent echocardiography demonstrated severe tricuspid valve regurgitation secondary to an avulsion of the tricuspid valve papillary muscle. He was promptly transferred to the regional pediatric trauma center for definitive treatment.

Physical examination on arrival to our facility showed a well-developed adolescent male in no acute distress. Cardiac auscultation revealed a 2/6 holosystolic murmur, most audible along the left sternal border. Examination of his abdomen revealed mild abdominal tenderness without peritoneal signs. Serial evaluations of his hematocrit were stable. Echocardiography confirmed severe tricuspid regurgitation with a flail chordal apparatus associated with the posterior leaflet of the tricuspid valve. There was associated mild right atrial and ventricular enlargement (Fig. 2).

Fig. 2.

Apical 4 chamber echocardiographic view with color Doppler comparison. There is rupture of the chordal apparatus of the posterior leaflet of the tricuspid valve, creating a flail leaflet and mechanism for severe tricuspid regurgitation. TV; tricuspid valve, TR; tricuspid regurgitation.

The patient remained stable in the Pediatric Cardiac Intensive Care Unit where a multidisciplinary team including pediatric general surgery, pediatric cardiac surgery, pediatric cardiology, and perfusion was assembled. The treatment priorities were discussed in detail. The urgent repair of his papillary muscle rupture would necessitate cardiopulmonary bypass and systemic anticoagulation, which could place him at increased risk of intra-abdominal hemorrhage in the early post-injury period. Alternately, delay in the repair of his cardiac defect would result in increased scarring and contraction of the subvalvular apparatus, which could put the long term success of his repair at risk. After finding no precedent in the pediatric literature regarding systemic anticoagulation for cardiopulmonary bypass in the setting of a grade III liver laceration, we elected to repair his cardiac defect two weeks post injury. It was felt that this time period would allow for enough healing of the hepatic parenchyma while not delaying the valve replacement repair to a detrimental degree. The patient was thus monitored until post injury day 5 and was then discharged home with strict activity restrictions.

On post-injury day 14, the patient returned to our facility. He underwent tricuspid valve repair with 30-mm annuloplasty ring, re-implantation of anterior papillary muscle, pericardial patch augmentation of the septal leaflet, bicuspidization with plication of the posterior leaflet annulus, and anterior leaflet resuspension. This was completed under cardiopulmonary bypass. The procedure was well tolerated and without complication. He at no time developed abdominal pain. Anemia was present, but it was asymptomatic and stable. He was discharged to home on post-operative day 3 in good condition. At one month post-op, he had returned to his baseline in terms of oral intake and bowel habits. Follow up echocardiography demonstrated no significant tricuspid regurgitation or stenosis.

2. Discussion

Cardiac injury in the pediatric trauma setting is a relatively rare occurrence. In recent review of the National Trauma Data Bank evaluating pediatric cardiac injury, only 0.03% of patients within the database met inclusion criteria for the study. The consequence of this rare occasion, however, is quite high, as a mortality rate of 40% was observed. Out of 626 children who sustained cardiac trauma, the mechanism was blunt in 65% (402 children) [1]. Of these 402 patients, 87% sustained a cardiac contusion. Damage to the cardiac valves accounted for less than 5% of cardiac injuries following blunt trauma [3]. Recognition of these rare entities is predicated upon a high index of clinical suspicion and early implementation of echocardiography.

Blunt cardiac trauma is a most often not an isolated injury [4]. Previous studies suggest that upwards of 90% of children with blunt cardiac injury also suffer from blunt trauma to one or more organ systems, with pulmonary contusions, pneumothorax, rib fracture, and liver injury being most common [5]. Our patient sustained pulmonary contusions without rib fracture or pneumothorax in addition to his cardiac and liver injuries but never required intubation or aggressive respiratory care.

Presentation of tricuspid valve rupture generally adheres to two distinct clinical pictures. Acute rupture of a papillary muscle, leaflet or chordae becomes evident early in the clinical course with the onset of a new cardiac murmur and hypotension. If the valvular structures are merely contused or transiently ischemic at the time of injury, however, a delayed presentation of right heart failure, as in our case, may be the more predominant symptoms [6]. The latter case has been reported in the literature to occur in as little as 24 h and as long as 25 years following injury [7].

In patients with severe tricuspid valve regurgitation secondary to blunt trauma and multiple associated injuries, the timing of tricuspid valve repair is critical. Despite initial hypotension and symptoms of early right heart failure most patients remain well controlled with medical therapy and can tolerate it for a significant period of time [8]. This is beneficial in the setting of a concomitant solid organ injury as this affords the ability to manage these injuries conservatively when indicated. Delaying tricuspid valve repair for too long, however, has been associated with significantly lower rates of repair secondary to scarring and contraction of the subvalvular apparatus [9]. This can lead to a higher rate of valve replacement and right heart failure [10]. In our report, we emphasize the importance of balancing the risk of bleeding from the liver laceration following heparinization for the valve repair with minimizing the delay in valve repair to lower the risks of prosthetic valve requirement and right heart failure. We therefore recommend waiting for 2–4 weeks to ensure stabilization of the abdominal injuries followed by tricuspid valve repair.

Outcomes for the non-operative management of grade III liver lacerations in pediatric blunt trauma have been well documented. Less than 5% of patients initially managed non-operatively for blunt hepatic injury go on the require intervention [8]. Angiographic embolization for blunt solid organ injury has been utilized in the management algorithm for adults since the mid 1990s. Kiankhooy et al. [11] reported 100% success rate of non-operative management in pediatric blunt hepatic injuries over five years at their institution. Of the 51 children with liver injuries, two underwent angiographic embolization for control of ongoing hemorrhage. The remaining 49 children were managed with supportive care and serial examinations. Had we been confronted with significant ongoing bleeding due to the hepatic injury, angiographic embolization would have been our first line therapy. Rebleeding after a period of hemodynamic and hematologic stability is a rare entity in pediatric blunt trauma; this too has been successfully managed with angiographic embolization in the limited reports in the non-operative management era literature [12].

The safety of systemic anticoagulation in the setting of a high grade solid organ injury is controversial in children. The dearth of literature which exists on the subject suggests that in adult patients with either a Grade I or II splenic injury, systemic anticoagulation does not appear to increase the risk of failure for non-operative management of those injuries [13]. Unfortunately, this has never been addressed in the pediatric trauma literature, and it is unclear how applicable the adult studies are to the pediatric trauma population. Due to this uncertainty, we chose a more conservative delay of 14 days between injury and cardiopulmonary bypass as we did not believe this delay would increase the risk of long term complications following valvular repair.

3. Conclusion

Blunt cardiac injury most frequently occurs in adolescent males in the setting of motor vehicle collision or pedestrian struck. It is often accompanied by significant injury to other organ systems above and below the diaphragm. Our patient underwent cardiopulmonary bypass for repair of a blunt tricuspid valve injury two weeks post-injury despite also suffering from a grade III liver laceration concurrently. We feel we succeeded in balancing this particular patient’s risk/benefit profile and did not subject him to any undue risk during this interval. To our knowledge, this is the first report of its kind.