EN | DE | PT Contact How to study Login Register

Clinical case: Chronic Thoracic Aneurysm - want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

Sign up for your free Kenhub account today and join over 852,397 successful anatomy students.

“I would honestly say that Kenhub cut my study time in half.” – Read more. Kim Bengochea Kim Bengochea, Regis University, Denver

Clinical case: Chronic Thoracic Aneurysm

“It was a very surreal feeling when I was diagnosed with a thoracic aortic aneurysm earlier this year, even more so when I found out that the aneurysm originated from a motor vehicle accident back in 1985 and had been present for nearly 30 years. Physically I felt fine, but mentally I suddenly felt vulnerable in terms of the aneurysm rupturing after sneezing or coughing, which I found difficult to get my head around.”

Read in this article the story of this lucky patient who was diagnosed with an aneurysm in the aortic arch.

Case key facts
Pneumothorax A collection of air in the pleural cavity diagnosed on a chest X-ray by the 'pneumothorax line'.
Cardiothoracic ratio

Maximal horizontal cardiac diameter/maximal horizontal thoracic diameter

A normal measurement should be less than 0.5.

Saccular aneurysm It resembles a small sack in shape and manifests with sharp, sudden pain in the chest, abdomen or upper back, shortness of breath, trouble breathing or swallowing
Isthmus of the aorta The terminal part of the arch of the aorta, between the points of origin of the left subclavian and posterior intercostal arteries
Thoracic endovascular aneurysm repair (TEVAR) Placing a stent in the aortic arch, sealing off the opening of the left carotid and left subclavian arteries, and then installing a bypass graft connecting the right carotid artery to the left one, together with the subclavian artery.

After reviewing this case you should be able to describe the following:

  • What a pneumothorax is. How a pneumothorax would be recognized on a chest radiograph.
  • What is meant by the cardiothoracic ratio? What is the normal range?
  • What a saccular aneurysm is. What are the risks associated with a saccular aortic arch aneurysm?
  • What causes calcifications in an aneurysm.
  • What the term “isthmus of the aorta” refers to.
  • What is meant by “debranching of the left aortic arch by right carotid to left carotid to left subclavian bypass
  • Your reaction to the patient’s perspective of his condition provided in this case.

This article is based on a case report published in the Journal "Case Reports in Surgery" in 2015, by Miller S, Kuman P, Van den Bosch R, and Khanafer A.

It has been modified and reviewed by Joel A. Vilensky PhD, Carlos A. Suárez-Quian PhD, Aykut Üren, MD.

Case Description

History & Physical Exam

A 47-year-old white Australian man presented to the emergency department with chest tightness and shortness of breath. He stated he did not have symptoms of fever, cough, or night sweats. Initially, his medical history seemed unremarkable. However, at the age of 18, he had been the driver in a single automobile accident in which his car had hit a pole at high speed and the patient had sustained bilateral pneumothoraces, liver lacerations, and splenic rupture requiring splenectomy. He had been using a seatbelt. At that time there was no indication of an injury of the arch of the aorta (Figure 1).

Figure 1. Cadaveric photograph showing normal arch of aorta.

The patient had not been admitted to a hospital since that accident and was otherwise noted to be healthy. The patient did not have risk factors for cardiac disease or pulmonary embolism and did not have any family history of aneurysma or cardiac disease.

On examination, his temperature was 36.5∘C, heart rate 76 bpm, blood pressure 139/64 mmHg, and saturation 98% on air. Chest and abdominal examination were unremarkable.

Imaging

A chest X-ray (CXR) showed clear lung fields with a cardiothoracic ratio within the normal range (Figure 2). There was however a smooth enlargement of the left hilum on CXR, thought to be due to an enlarged main pulmonary artery.

Figure 2. PA chest radiograph showing some enlargement at right pulmonary hilum indicative of the aortic arch aneurysm. Also evident in this patient is a Chilaiditi sign, which is incidental to the case. In this condition the right colic flexure is anterior to the liver. It can be symptomatic or asymptomatic.

Subsequent computed tomography (CT) imaging of the chest revealed however a 5.4 cm saccular thoracic aneurysm of the aortic arch near to the origin of the left subclavian artery (Figure 3). The presence of peripheral calcifications (Figure 3A, B) in the aneurysm suggested that it was long-standing and therefore an unlikely cause of the patient’s acute symptoms, which remained unknown. There was no indication of perianeurysmal fluid accumulation and no evidence of rupture of the aneurysm.

Figure 3. A. Axial CT image showing aortic aneurysm (AN); B. Coronal CT image showing the aneurysm.

CT angiogram of the thoracic aorta confirmed the findings and suggested that the proximal margin of the aneurysm lay adjacent to the posterior wall of the left subclavian artery and was 19mm downstream from the posterior wall of the left common carotid artery. The region of the aorta that contained the aorta is known as the isthmus of the aorta.

Figure x. 3D reconstruction showing the aortic arch and the extension of the aneurysm.

Diagnosis & Management

The patient’s past history of trauma was believed to be the most likely cause of his aneurysm. Despite being slightly hypertensive at presentation, there were no subsequent concerns about the patient’s blood pressure. He was relatively young and had no history of systemic inflammatory disease. Examination was not consistent with Marfan syndrome and his history was not consistent with a chronic infectious state such as syphilis, and his inflammatory markers were normal. Furthermore, the patient had no documented history suggestive of atherosclerosis. Lastly, the aneurysm’s saccular shape and position were typical of those found in chronic traumatic thoracic aortic aneurysms.

Six weeks after his initial examination, the patient underwent elective thoracic endovascular aneurysm repair (TEVAR) with debranching of the left aortic arch by right carotid to left carotid to left subclavian bypass - the surgeons placed a stent in the arch of the aorta. That stent practically sealed the aortic wall at the distal arch and blocked the opening of left carotid and left subclavian arteries. To alleviate that problem, the surgeons installed a bypass graft that connected the right carotid to the left carotid and left subclavian arteries superior to the arch of the aorta. Thus left carotid and left subclavian receive blood from the right carotid artery and not directly from aorta.

Evolution

At twelve weeks after the procedure, the patient returned to his job as an emergency department nurse and at nine months postoperative his health remains well.

Patient’s Perspective

It was a very surreal feeling when I was diagnosed with a thoracic aortic aneurysm earlier this year, even more so when I found out that the aneurysm originated from a motor vehicle accident back in 1985 and had been present for nearly 30 years. Physically I felt fine, but mentally I suddenly felt vulnerable in terms of the aneurysm rupturing after sneezing or coughing, which I found difficult to get my head around. As a health professional I understood the seriousness of my condition and the complications of the aneurysm rupturing and how lucky I was to have spent 30 years living a carefree life, doing regular and at times very intense exercise and activities.

When I was diagnosed, any ache or pain I experienced made me worry that the aneurysm would rupture. After the operation I feel physically no different from how I did before the procedure, but mentally I feel less vulnerable, especially since I have had my follow-up CT which shows no evidence of complication after thoracic aortic stent graft.

Anatomical and Surgical Considerations

Causes, Signs, and Symptoms of Chronic Thoracic Aneurysms

The arch of the aorta arises from the left ventricle and passes to the left and typically gives rise to three major vessels, the brachiocephalic trunk and then the left common carotid and left subclavian arteries (Figure 1+x). Aneurysms of the isthmus of the aorta (see objective 5), as in the case described here, are typically found in individuals above 60 years old. The ligamentum arteriosum (Figure 1) is associated with the arch of the aorta. It is the remnant of the ductus arteriosus and passes from the pulmonary trunk to the isthmus of the aorta arch.

Figure x. An illustration showing the aortic arch and its main branches.

Rapid deceleration and the application of shearing forces may result in thoracic aortic injuries, typically at the isthmus. The vulnerability of this anatomical area is believed to be related to the tethering of the descending aorta by the ligamentum arteriosum; however there may be additional reasons for the sensitivity of this region.

Patients who have chronic traumatic aortic aneurysms may present with nonspecific signs including haemoptysis, thoracic pain, hoarseness, and back pain.

Management of Chronic Thoracic Aneurysms

There are few guidelines available that are specifically concerned with the management of chronic thoracic aneurysms. In the majority of cases, management should be similar to that of thoracic aneurysms of other causes, in which surgical intervention is considered based upon patient symptoms and documented radiological enlargement. In the case described here, a decision was made for surgical intervention due to the patient’s relatively young age and anxiety about his diagnosis. The minimally invasive TEVAR technique involves inserting a catheter through the femoral artery and the implantation of a stent graft within the aneurysm under imaging guidance.

Objective Explanations

Objectives

  • What a pneumothorax is. How a pneumothorax would be recognized on a chest radiograph.
  • What is meant by the cardiothoracic ratio? What is the normal range?
  • What a saccular aneurysm is. What are the risks associated with a saccular aortic arch aneurysm?
  • What causes calcifications in an aneurysm.
  • What the term “isthmus of the aorta” refers to.
  • What is meant by “debranching of the left aortic arch by right carotid to left carotid to left subclavian bypass
  • Your reaction to the patient’s perspective of his condition provided in this case.

Pneumothorax

A pneumothorax is a collection of air in the pleural cavity (space). Pneumothorax may occur as a result of disease processes or trauma. In a pneumothorax, the parietal pleura remains adherent to the thoracic wall while the visceral pleura retracts with the deflating lung toward the hilum. The diagnosis of pneumothorax requires identification of the line that represents the visceral pleura, and the absence of lung markings between that line and the chest wall. The “pneumothorax line” is required for definite diagnosis (Figure 4A and 4B).

The treatment for pneumothorax involves insertion of a chest tube that is connected to a vacuum. Re-creating the negative pressure in the pleural cavity results in the lung expanding to its normal size.

Figure 4. An example of pneumothorax in a direct film (not from this case). A. The outer area of the right lung is the air filled thorax, which does not have any lung tissue. The inner area is the collapsed right lung due to loss of negative pressure in the pleural cavity, the blue arrow is pointing to the line that separating the two areas. B. shows the same patient after the insertion of a chest tube later in the same day, which has fully expanded right lung.

Cardiothoracic Ratio

The cardiothoracic ratio (CTR) is a radiographic measure that assists in the detection of abnormal enlargement of the cardiac silhouette, which typically is associated with cardiomegaly, but can result from other processes such as a pericardial effusion. The CTR is measured on a PA chest radiograph, and is the ratio of the maximal horizontal cardiac diameter relative to maximal horizontal thoracic diameter. A normal measurement should be less than 0.5.

Figure x. CXR image demonstrating how to calculate the CTR value.

Saccular Aneurysm

A saccular aneurysm is an aneurysm that resembles a small sack in shape as opposed to the more typical fusiform shaped aneurysm. Those with aortic aneurysms risk it rupturing and then hemorrhaging to death. The typical symptoms of an aortic aneurysm are sharp, sudden pain in the chest, abdomen or upper back, shortness of breath, trouble breathing or swallowing.

Causes of Calcifications in Aneurysms

Calcifications in any part of the aorta are associated with arteriosclerosis and inflammatory processes in the aortic wall. Generally, such calcifications especially in an aneurysm would be associated with an increased risk of rupture.

Isthmus of the Aorta

The isthmus of the aorta is the terminal part of the arch of the aorta, just distal to the origin of the left subclavian artery and proximal to the origin of the third posterior intercostal artery. This region is named as such because it is a region of reduced blood flow during fetal life due to the diverted flow within the ductus arteriosus. With birth and the closing of the duct, the isthmus grows to appear the same size as the surrounding parts of the aorta. If this does not occur, the patient can develop coarctation of the aorta.

Clinical case: Chronic Thoracic Aneurysm - want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

Sign up for your free Kenhub account today and join over 852,397 successful anatomy students.

“I would honestly say that Kenhub cut my study time in half.” – Read more. Kim Bengochea Kim Bengochea, Regis University, Denver

Show references

References:

  • Miller S, Kuman P, Van den Bosch R, Khanafer A. Chronic Thoracic Aortic Aneurysm Presenting 29 Years following Trauma. Case Reports in Surgery Volume 2015, Article ID 470917, 4 pages.
  • Modified by Joel A. Vilensky PhD, Carlos A. Suárez-Quian PhD, Aykut Üren, MD.

Layout:

  • Abdulmalek Albakkar
  • Adrian Rad

Illustrators:

  • Aortic arch and its branches - anterior view - Yousun Koh

© Unless stated otherwise, all content, including illustrations are exclusive property of Kenhub GmbH, and are protected by German and international copyright laws. All rights reserved.

Related Atlas Images

Heart in situ

Anterior view of the heart

Contents of the mediastinum

Continue your learning

Article (You are here)
Other articles
Well done!

Register now and grab your free ultimate anatomy study guide!

Create your free account.
Start learning anatomy in less than 60 seconds.