Tracheo Innominate Artery Fistula

Etiology

Several conditions can predispose to the development of a TIF. These include pressure necrosis caused by the tracheostomy cuff, prolonged use of steroids or immunosuppressants, placement of tracheostomy below the third tracheal ring, tracheitis, prolonged intubation, anomalous/high anatomic location of the innominate artery and extension of a skin infection at the stoma site to the deeper space.[4]

Epidemiology

The reported incidence of TIF is under 1% in most studies. In the majority of patients (about 70%), TIF develops within the first 3 weeks after placement of tracheostomy. However, TIF has been reported in patients 1 or more years from the placement of tracheostomy as well. [5]

Pathophysiology

The innominate artery usually traverses the trachea between the 6-9th cartilage ring. Thus, when a tracheostomy is placed lower than the 3rd tracheal ring, the risk of a Tracheoinnominate fistula increases. Over-inflation of the cuff is also a known risk for the fistula as it can erode into the posterior segment of the innominate artery. Other risk factors include the use of corticosteroids, radiation therapy to the neck area and recurrent episodes of hypotension causing ischemia.

Several factors can contribute to the friability of tissues and promote the development of a fistulous connection between the trachea and the innominate artery. The first event is the formation of an ulcer due to localized ischemia or infection. This ulceration then progresses to the formation of a fistula between the trachea and the innominate artery.  

History and Physical

Patients with TIF have a prior history of tracheostomy. Some of these patients will present with a small amount of bleeding 24 to 48 hours before the occurrence of massive hemorrhage. This is called the sentinel or herald bleed, and it can occur in up to 30% of patients with TIF. Patients will present with bleeding, often pulsatile, from around the tracheostomy site. They can also have hemoptysis (which may be associated with a threatened airway) or febrile episodes. Patients may exhibit hemodynamic instability and hemorrhagic shock depending on the severity of the bleeding. The majority of patients present within 3-6 weeks following a tracheostomy.

Evaluation

Urgent evaluation is crucial in dictating the success of therapy. Bronchoscopy, conventional angiography or computed tomography angiography can all be used in making the diagnosis of TIF. However, all of these imaging modalities have limited sensitivity in diagnosing the condition. Therefore, a high index of clinical suspicion is important as well. On bronchoscopy, direct visualization of the active bleeding site on the anterior wall of the trachea may be seen. Both conventional angiography and computed tomography angiography will reveal a blush from the innominate artery into the trachea.[6][7]

Treatment / Management

Immediate management of this condition relies on its prompt diagnosis. The Utley maneuver can immediately control the hemorrhage. In this maneuver, place a finger through the incision to apply direct pressure on the artery against the posterior sternum and compress it. A similar tamponade effect can be achieved via the over-inflation of the cuff of the tracheostomy tube. One should immediately call for additional assistance as the patient will require emergency airway control, and this will require additional personnel to maintain control of hemorrhage simultaneously. The best option is to place a cuffed endotracheal tube beyond the site of bleeding. Also, the patient should have blood readily available.

In the current era, most institutions have a massive transfusion protocol that can be quickly activated. Depending on the institution, the management of this condition can be spearheaded by trauma/acute care surgery, cardiac surgery, thoracic surgery, or vascular surgery teams. Subsequent management can either be via open surgical technique or through endovascular maneuvers. The open surgical technique involves median sternotomy or a variation of it such as a collar incision with a partial sternotomy, ligation, and division of the innominate artery. Ligation without division of the innominate artery should not be performed as the artery can re-fistulize. The innominate artery may need to be buttressed with a patch such as pericardial or venous, or pledgets. The defect in the trachea is covered with a muscle flap (such as pectoralis major). In most cases, extensive tracheal resection or reconstruction is not performed or needed. Other materials that can be used for protection against infection include pericardium, thymus or pleura. Up to 10% of patients may experience a neurologic event after ligation of the innominate artery.

Some authors have described performing an innominate to carotid artery bypass, aorta to innominate artery bypass, aorta to axillary artery bypass or carotid to carotid artery bypass, although this is generally not the standard practice because of the potential risk of infection from the TIF. Therefore, these bypasses should be performed selectively. Use of synthetic materials (such as PTFE), cryopreserved arterial allografts and autologous vein grafts have been described for these bypasses in literature. Post-operative complications can include mediastinitis, fistulization, and sternal wound infection.[8][7][9](B3)

Endovascular techniques are maybe preferable in a patient who is at prohibitively high risk for open surgery. It may also be preferable in patients with a prior history of a median sternotomy, thoracotomy, and chest radiation. For endovascular stent-graft placement, selective catheterization of the innominate artery and adequate seal zones are required.

Some authors have described hybrid procedures that employ both endovascular and open surgical techniques whereby a surgical bypass is performed (such as a carotid-subclavian bypass) along with placement of an endograft stent as the bypass provides longer landing zones. The stent can place via the femoral artery or direct cutdown on other vessels such as the carotid artery or the brachial or axillary artery. Completion angiography is performed at the conclusion of the procedure to confirm technical success. Complications from this procedure can include access site complications (such as hematoma), stent migration, mal-deployment or fracture. Recurrent TIF has been described in the setting of a stent-graft fracture. In the case of an inadequate seal, an endoleak may develop leading to ongoing hemorrhage from the TIF.

In certain cases, endovascular stenting can be used as a bridge to temporize the emergency situation, allowing time to resuscitate and stabilize the critically ill patient. More definite open surgical intervention can then be performed in the future in an elective to semi-elective manner. In a critically ill patient with ongoing bleeding, placement of an occlusion balloon (such as a Fogarty catheter) under fluoroscopic guidance in the innominate artery can be a life-saving maneuver, and this can be achieved via transfemoral or transbrachial routes. This can buy some time to contemplate on or mobilize resources for a more definitive repair option. Under fluoroscopic guidance, some authors have described the use of coil embolization for the control of the bleeding from the innominate artery with the selective performance of a bypass to preserve cerebral circulation as well.

Differential Diagnosis

Bleeding from around the tracheostomy site can be mistaken for bleeding from stomal granulation tissue. Early bleeding from tracheostomy can be due to inadequate procedural hemostasis or coagulopathy.

Prognosis

Patients should be monitored closely in the intensive care unit after intervention as there is a chance of rebleeding despite apparently successful procedures. Prognosis is guarded even with prompt recognition and management. Most of these patients are debilitated and residing in the intensive care unit at the time of the hemorrhagic event with multiple ongoing medical ailments. Perioperatively, the condition is associated with a higher than 50% mortality.