Blunt traumatic aortic rupture of the proximal ascending aorta repaired by resection and direct anastomosis

Abstract

Traumatic aortic injury represents 15% of motor vehicle related deaths with death occurring at the scene in 85% of the cases. Aortic disruptions usually occur at the isthmus in a transverse fashion with all three of the aortic layers being involved. Herein, we report the case of a 68-year old man with no prior medical history who was struck by a vehicle while riding his bicycle. The ruptured segment of aorta was resected circumferentially and interrupted horizontal mattress pledgeted prolene sutures were used to ensure full thickness aortic integrity of the proximal and distal aortic segments. The aorta was closed with a single-layer technique using 4/0 prolene suture. There were no postoperative complications and patient was discharged on Day 44. The case here discussed demonstrates a rare presentation of blunt aortic injury. The proximal ascending aorta is an unusual site of transection following blunt trauma with few reports in the literature. We were able to repair the aorta with direct suture, thus avoiding the use of artificial material.

CASE PRESENTATION

A 68-year old man with no prior medical history was struck by a motor vehicle while riding his bicycle. After intubation at the scene, the patient was transferred to a district hospital where he was resuscitated further and initial investigations were undertaken. Chest computed tomography (CT) found a contrast leak from the proximal ascending aorta on the left anterolateral surface (Fig. 1). The remainder of the aorta was normal. The patient had become haemodymically unstable after developing a Glasgow Coma Scale of 3 at the scene. Associated injuries were bilateral pulmonary contusions with bilateral rib fractures and fractures of the fifth, sixth and seventh thoracic vertebrae. There were no associated intracranial injuries. On transthoracic echocardiography, the ascending aorta was measured at 4.0 cm, which corresponded to the CT measurements. The aortic valve was trileaflet and functionally normal with normal left ventricular ejection fraction. The emergency staff contacted our centre at which point a traumatic aortic rupture was confirmed and emergency transfer to our institution was arranged. Upon arrival at our institution, the patient was taken immediately to the operating theatre.

Figure 1:

Preoperative 3D CT scan showing aortic rupture with contrast leak.

Under general anaesthesia, femoral arterial and venous cannulation was performed for cardiopulmonary bypass. Median sternotomy was performed, following which the pericardium was opened revealing a bleeding full thickness aortic rupture 1 cm distal to the sinotubular junction. There was circumferential full thickness involvement of the aorta with sparing of a 2-cm segment posteriorly. The distal ascending aorta was immediately cross clamped, the aorta opened at the site of rupture and cold crystalloid antegrade cardioplegia administered in each coronary ostia to achieve diastolic myocardial arrest. The posterior uninvolved segment of the aorta revealed intact intima with normal internal appearance of the rest of the aorta with no evidence of dissection and a normal tricuspid aortic valve. The ruptured segment of aorta was resected circumferentially with a margin of 4 mm, and interrupted horizontal mattress pledgeted 4/0 prolene sutures were used to ensure full thickness aortic integrity of the proximal and distal aortic segments. The aorta was then closed with a single-layer technique using 4/0 prolene suture.

Postoperatively, the patient required prolonged ventilation due to the bilateral rib fractures and associated bilateral pulmonary contusions and effusions. The patient was discharged from the intensive care unit on Day 22 postoperatively and from hospital to his home on Day 44.

At 6 months, the patient was well and had resumed normal activities. Echocardiographic and CT examination were unchanged compared with the predischarge studies (Fig. 2).

Figure 2:

Postoperative 3D CT scan showing repair of the aorta.

DISCUSSION

Traumatic aortic injury represents 15% of motor vehicle related deaths with death occurring at the scene in 85% of the cases [1, 2]. Blunt aortic injury to the thoracic aorta remains the second leading cause of death from vehicular trauma with 94% of victims dying within 1 h of injury [1, 2]. Of the patients who make it to the hospital alive, 75% are initially haemodynamically stable [2].

Aortic disruptions can occur in all segments of the aorta. Surgical series demonstrate that 92% of aortic injuries occur at the isthmus with 3% occurring in the ascending aorta, 4% in the arch and 1% involving the distal descending aorta [2]. This is in contrast to autopsy series where 65% of injuries occur at the aortic isthmus, 14% in the ascending aorta and arch, 12% in the distal descending aorta and 9% in the abdominal aorta [1, 4]. In one series [3], 58% of aortic injuries were transections and 42% were tears, a transection being a disruption of all three aortic layers, with a tear defined as a partial disruption of a varying length of the same two layers with the adventitia remaining intact [1].

Aortic transections occur in a transverse fashion with all the aortic layers involved typically with the edges separated by several centimetres [4]. Most injuries occurring at the isthmus are transections; however, this is the case in less than a third of injuries of the ascending aorta [1].

The ligamentum arteriosum, the left main stem bronchus and the paired intercostal arteries limit movement of the proximal descending aorta, and experiments have suggested that displacement of the aorta in a cranial or caudal direction can cause traction tears at the isthmus [5]. Another theory is that hydrostatic pressure rapidly elevates at impact due to deceleration forces, producing a ‘water hammer’ effect and the aorta bursts and tears at its weakest point [5].

We decided to perform a direct closure of the aorta as there was a localized discrete aortic tear without intramural haematoma or dissection. Although replacement of the aorta was considered, prosthetic graft material was avoided as it was not indicated given a maximal aortic size of 4 cm and a functioning trileaflet aortic valve in a patient of 80 kg and 168 cm. Subsequent histological analysis did not reveal any collagen or connective tissue disorder.

This case demonstrates a rare presentation of blunt aortic injury. The proximal ascending aorta is an unusual site of transection following blunt trauma with few reports. We were able to repair the aorta with direct suture, thus avoiding the use of artificial material.

Conflict of interest: none declared.