Infected False Aneurysm of Brachiocephalic Trunk - Rare but Highly Lethal Cause of Dyspnea

Abstract

False aneurysm of the brachiocephalic trunk is a very rare but highly lethal, life-threatening, and difficult-to-treat condition. In this report, we present a case of a patient who suffered from rapidly worsening dyspnea caused by infected false aneurysm of the brachiocephalic trunk compressing the trachea that was successfully treated by stent graft implantation. The main purpose of this article is to consider other, less common causes of dyspnea and to explain the pathogenesis of infected true/false aneurysm and its management. Due to the rarity, history-taking and physical examination should be thorough, and symptoms and signs should be analyzed deeply. Simplification should be avoided during diagnosis. In addition, we would like to highlight the option of stent grafts as an alternative to surgery in the management of patients suffering from infected aneurysm who are at high surgical risk.

INTRODUCTION

Dyspnea is one of the main complaints of patients presenting to the emergency department [1]. Its prevalence varies among clinical settings and patient subgroups: 3% to 25% in the community, 3.7% in outpatient clinics, 2.7% to 5.2% in emergency rooms, and 15% to 25% at hospital admissions [2]. Dyspnea is a presenting symptom of many diseases, including cardiovascular and primary pulmonary diseases, cancer, and metabolic diseases, thus making the differential diagnosis more challenging.

This case report presents a unique and rare vascular cause of dyspnea: an infected false aneurysm of the brachiocephalic trunk that was successfully managed by an endovascular procedure.

This treatment option performed in the patient was not part of a scientific study, but it intended to save a patient life. It was a high risk, life-threatening emergency, therefore it could not be approved by the Institutional Review Board. However, the informed consent was signed by the patient and study protocol complied with ethical standards on human experimentation and the Helsinki Declaration.

CASE

An 89-year-old Caucasian female was admitted to a local hospital for gradually worsening dyspnea. Seven days before hospital admission, her general practitioner prescribed antibiotics for fever. However, the etiology of fever was not sufficiently differentiated. Three days after the patient started using the antibiotics, she began to complain of dyspnea with gradually worsening severity. The overall duration of dyspnea was three days, and the duration of fever was seven days in ambulatory care, i.e., before admission to the local hospital.

Physical examination revealed a frail female suffering from dyspnea on minimal exertion and speaking. Her body temperature was 37.6°C, hemoglobin saturation was 89%, and blood pressure was 110/60 mmHg. The heart was beating regularly at a rate of 90 pulses per minute. Auscultation of the lungs revealed barely audible inspiratory crackles on the upper lobe of right lung with weakened vesicular breathing.

Chronic wounds, as a manifestation of chronic venous disease (CVD) were evident around the ankles bilaterally. A detailed physical examination did not identify any other significant abnormalities.

She was treated for multiple comorbidities, i.e., arterial hypertension, CVD CEAP (Clinical, Etiological, Anatomical, and Pathophysiological) C6 bilaterally, chronic systolic heart failure, permanent atrial fibrillation, hypercholesterolemia, and diabetes mellitus. There was no past history of blunt chest trauma or cannulation of the jugular veins.

1) Management at the local hospital

The initial laboratory examination demonstrated elevated levels of inflammatory markers. Laboratory findings during hospitalization are listed in Table 1. The initial chest radiograph (Fig. 1) revealed a widened superior mediastinum and right hilar enlargement of the lungs. An inflammatory process in the chest was suspected, and decompensated heart failure was excluded as a cause of dyspnea.

Table 1.

Laboratory findings during hospitalization at a local hospital

Parameter	Days of hospitalization
	First	Third	Fifth
	Hemoglobin (g/L)	112.0	111.0	96.0
Erythrocytes (×1012/L)	3.5	3.4	3.0
Platelet count (×109/L)	318.0	387.0	477.0
Leukocytes (×109/L)	16.5	16.9	11.8
Neutrophils (×109/L)	14.6	14.8	9.9
Urea (mmol/L)	3.4	4.7	4.0
Creatinine (μmol/L)	52.9	59.8	59.3
C-reactive protein (mg/L)	215.6	240.6	163.6
Aspartate aminotransferase (μkat/L)	0.2	0.6	0.5
Alanine aminotransferase (μkat/L)	0.1	0.4	0.4
Sodium (Na+) (mmol/L)	134.1	137.2	141.1
Potassium (K+) (mmol/L)	3.9	3.6	4.4
Chloride ion (Cl-) (mmol/L)	98.7	103.0	106.0
Glucose (mmol/L)	5.8	5.1	5.7
Brain natriuretic peptide (pg/mL)	119.0	NA	NA

NA, not available.

Fig. 1.

The initial chest radiograph.

Blood culture and culture of swabs taken from chronic venous ulcers of the lower extremities were performed, and empirical antibiotic intravenous treatment with third-generation cephalosporins, i.e., cefotaxime, 2 g three times a day (every 8 hours), was administered. Despite therapy, the patient’s clinical status continued to worsen. New symptoms and signs, i.e., dysphonia and dysphagia, appeared on the third day of hospitalization.

Therefore, the patient was referred to an otolaryngologist who suspected a tumor of the right piriform sinus and recommended a computed tomography (CT) of the mediastinum.

Meanwhile, results of blood and venous ulcer swab cultures revealed Staphylococcus aureus that was sensitive to fluoroquinolones; therefore, cephalosporins were replaced with ciprofloxacin, administered intravenously, at a dose of 400 mg three times a day (every 8 hours).

Computed tomographic angiography (CTA) of the mediastinum was performed, revealing a huge false aneurysm of the brachiocephalic trunk (70×50×65 mm) compressing the surrounding structures (Fig. 2, 3). Given the high risk of rupture associated with it, the patient was transferred to a specialized vascular center on the fifth day of hospitalization.

Fig. 2.

Initial computed tomographic angiography (CTA) scan of the mediastinum. (A) Multiplanar reconstruction demonstrated false aneurysm of brachiocephalic trunk. The CTA image is typical for false aneurysm - irregular contour, missing three characteristics parts of arterial wall (intima, media, and adventitia), and neck of false aneurysm (arrow). (B) CTA scan of mediastinum showed compression of trachea by false aneurysm. The diameter of trachea was reduced to 30% in the area of compression. The diameter of trachea was: 14 mm above stenosis, 5 mm in stenosis, and 15.5 mm bellow stenosis. The maximum deviation of trachea from centerline was in the middle of length between larynx and bifurcation of trachea. Distance of this deviation was approximately 11 mm to the left side from centerline and deviation angle was between 18-20 degrees.

Fig. 3.

Volume rendering image (three-dimensional image) of initial computed tomographic angiography scan showed the aorta, its branches, and false mycotic aneurysm of brachiocephalic trunk.

2) Management in the vascular center

After admission to the vascular center, the patient suffered from resting dyspnea and inspiratory stridor. She had an altered status of consciousness due to severe hypoxemia; hemoglobin saturation was 78% without inhalation of oxygen.

The heart rate was 110 beats per minute. During physical examination, increased filling of the internal jugular veins and superficial veins of the thorax was apparent (Fig. 4), due to compression of the superior vena cava.

Fig. 4.

Photograph of the patient taken at the beginning of hospitalization in the vascular center. The arrows mark the dilated superficial veins of thorax due to their increased filling and venous pressure caused by compression of superior vena cava.

The infected false aneurysm of brachiocephalic trunk compressing the surrounding structures was considered a reason for occurrence of the symptoms and signs, based on their rapid progression and severity, elevation of C-reactive protein (CRP), positive blood culture, and the characteristic CT images. S. aureus was identified as the microbiological agent.

A multidisciplinary discussion regarding the treatment options for infected false aneurysm led to the conclusion that benefits of an endovascular procedure would outweigh those of open reconstruction due to the expected high risk of death or complications in case of open surgery, considering the patient’s advanced age and comorbidities.

3) Endovascular procedure

Fig. 5 shows the planning of the endovascular procedure, i.e., measuring the diameters and lengths of the arteries for appropriate stent graft choice and achieving adequate sealing. The sizing and planning for the endovascular procedure was performed using GE Advantage Workstation (GE HealthCare).

Fig. 5.

The sizing and planning for endovascular procedure. Autobone and VesselIQ Xpress (GE HealthCare) imaging software were used for vessel analysis. (A) The diameter of the origin of the brachiocephalic trunk (BT) (proximal diameter) was 10.3 mm. (B) The length of the BT (from origin to bifurcation) was 40.4 mm. (C) The diameter of the distal part of right common carotid artery (RCCA) (measured approximately 60 mm after the beginning of RCCA; distal sealing zone) was 7.6 mm. (D) The distance between the origin of the BT and the neck of false aneurysm of the BT was 13.5 mm. (E) The distance between the origin of the BT and origin of right vertebral artery (RVA) was 67.9 mm. The diameter of the right subclavian artery (RSA) approximately 60 mm after origin of the BT was 7 mm (distal sealing zone on RSA). (F) The distance between the origin of the RSA and origin of RVA was 37.5 mm. Dmin, minimal diameter; Dmax, maximal diameter.

The right femoral artery and right brachial artery were punctured, and two Amplatz guidewires (Boston Scientific) were introduced: the first one from right femoral artery into the right common carotid artery, and the second one from right brachial artery through the right subclavian artery into the ascending aorta. Then stent grafts were delivered, pre-positioned and “kissing” in brachiocephalic trunk, also into the right common carotid artery (Fluency 10×40 mm prolonged with Fluency 8×100 mm; Bard) and the right subclavian artery (Fluency 7×60 mm). Balloons were inflated in both stent grafts together. No leakage of iodine contrast into the cavity of the false aneurysm was visualized. The symptoms due to compression relieved immediately after the procedure.

The abovementioned antibiotic therapy i.e., ciprofloxacin, 400 mg three times a day intravenously, was continued throughout hospitalization in the vascular center. The overall duration of parenteral antimicrobial treatment with ciprofloxacin was three weeks. Two days before discharge, parenteral antimicrobial treatment was changed to oral ciprofloxacin, 500 mg twice a day.

4) Follow-up

A control CTA was performed one month after the procedure (Fig. 6). An approximately 5-mm reduction in the diameter of the false aneurysm mass was noted, with excellent sealing without leakage of iodine contrast. Antimicrobial therapy with ciprofloxacin at a dose of 500 mg twice a day orally was prolonged up to three months after the procedure. After that, no symptoms of compression, fever, or subfebrility were observed, the level of CRP was 10 mg/L; hence, the antibiotic treatment was discontinued.

Fig. 6.

Control computed tomographic angiography after stent graft implantation showed “kissing stent-graft” in the brachiocephalic trunk. There was no leakage of iodine contrast into the cavity of the false aneurysm. The arrow showed a smooth, less dense area presenting fully occluded cavity of the previous false aneurysm (A) coronal plane and (B) sagittal plane.

DISCUSSION

In the present case of an 89-year-old Caucasian female, the infected false aneurysm compressing the trachea, esophagus, and superior vena cava was considered to be a reason for the patient’s symptoms and signs. Given the presence of bacteremia at the onset of the fever, it was suspected that S. aureus was the cause of the infection.

False aneurysm of the brachiocephalic trunk is a very rare but highly lethal, life-threatening, and difficult-to-treat condition [3,4]. Majority of brachiocephalic trunk false aneurysms occur post blunt or penetrating chest trauma. Other causes include infection, cannulation of the internal jugular vein, or malignancy [4,5].

False aneurysm may cause local compression, thrombosis, or distal embolization, giving rise to a diverse range of symptoms including dyspnea, dysphagia, hoarseness, facial and upper right limb edema, chest pain, digital ischemia, right hemispheric symptoms, amaurosis fugax, vertebrobasilar syndrome, and, rarely, the presence of a pulsatile anterior thoracic mass [4].

There are no clear guidelines for the treatment of false aneurysm of the brachiocephalic trunk in the literature, and only experiences presented in previous case reports can be applied [6]. Treatment of such false aneurysms involved a major operation with a median sternotomy or thoracotomy in the past, causing a number of serious complications such as stroke and death. However, several case reports describing endovascular management, especially for traumatic false aneurysms, can be found in the literature [6-8].

Despite the indisputable advantages of stent grafts use in the treatment of traumatic or iatrogenic false aneurysms, their use is questionable in the management of infected false or true aneurysms due to high risk of prosthesis infection.

A typical, infected true aneurysm is caused by septic emboli in the vasa vasorum due to hematogenous spreading during bacteremia or by direct extension of an adjacent infection leading to an infectious degeneration of the arterial wall and aneurysm formation [9].

The infected false aneurysm arises in the similar manner as infected true aneurysm, i.e., infectious arteritis leads to the destruction of arterial wall, however the formation of a blind, saccular outpouching contiguous takes place that’s wall does not contain all three layers (intima, media and adventitia) of arterial wall, in contrast with true infected aneurysm.

When the aorta is affected, open surgical repair, i.e., resection of the aneurysm, extensive local debridement, and revascularization, is regarded as the gold standard for definitive treatment of infected true aortic aneurysm, unlike that for non-infected aortic aneurysms [9].

However, the European Society for Vascular Surgery (ESVS) guidelines dealing with aorta pathologies admit the possibility of treating infected aneurysm of an aorta by stent graft implantation as an acceptable alternative to surgical treatment [9].

The infected false aneurysm of the brachiocephalic trunk in the presented case was successfully managed by parallel stent graft implantation, i.e., kissing technique, from the brachiocephalic trunk to the right common carotid artery and right subclavian artery. Intravenous antimicrobial therapy was administered five days before the endovascular procedure for a total duration of three weeks; this was then replaced with oral antimicrobial treatment, which was continued for three months.

Regarding the preoperative antimicrobial treatment, the endovascular procedure should be postponed in a hemodynamically stable patient with infected false aneurysm for a short period, and intravenous antimicrobial therapy should be administered. This short period could provide sufficient time for penetration of antibiotics to the arterial wall and hematoma to achieve their effective concentrations in the “coagulum”; this is indicated by decreased levels of inflammatory parameters.

In case of infected false or true aneurysm treated by endovascular procedure (stent graft implantation), which is considered to be permanent, the total duration of postoperative antimicrobial therapy is controversial. A longer duration of antimicrobial treatment could be more beneficial than short duration. The latest ESVS guidelines dealing with management of mycotic aneurysm of aorta recommend long-term antimicrobial therapy, i.e., from 6-12 months to life-long. However, there are concerns about long-term (lifelong) antibiotic treatment. In our opinion, it could lead to several difficulties. First, there is a high risk of pseudomembranous colitis development. Second, resistance to antibiotics could develop.

The further clinical visit including CRP and CTA will be performed six months after the prior clinical visit, i.e., nine months after endovascular procedure. This will be followed by clinical visit and CTA annually. If clinical, laboratory (CRP), and CTA signs of infection recurrence are documented, antimicrobial therapy will be resumed.

In summary, false aneurysm of the brachiocephalic trunk is a rare condition whereas infected false aneurysm is even more unusual and rarer. There are no clear recommendations on the management of infected false aneurysms of the brachiocephalic trunk. Despite this, several case reports have demonstrated successful endovascular management of an infected false aneurysm of the brachiocephalic trunk [10,11]. The results presented in this report highlight endovascular treatment as an alternative to surgical treatment in high-risk patients, i.e., elderly patients with severe comorbidities. However, surgical resection and vascular reconstruction of infected false aneurysm will be beneficial for a majority of patients with average surgical risk [12,13].

Funding Statement

FUNDING None.