Representation of the various aortic aneurysms in CV

Aneurysms in the aorta are classified based on their anatomical locations. Largely, they can be divided into two classes: thoracic aortic aneurysm (TAA), those that are in the thoracic aorta, and abdominal aortic aneurysm (AAA), those that are in the abdominal aorta.

Thoracic aortic aneurysm (TAA) can further be divided into:

1. Aortic root aneurysm
2. Ascending aortic aneurysm
3. Aortic arch aneurysm
4. Descending aortic aneurysm
5. Aneurysm that straddles multiple portions of the aorta (i.e. from aortic arch to descending aorta)

Abdominal aortic aneurysm (AAA) can be classified as:

1. Suprarenal aortic aneurysm: above the kidneys
2. Infrarenal aortic aneurysm: below the kidneys.
3. Others: Pararenal, Jaxtarenal aortic aneurys.

Most patients with aortic aneurysms (AA) are asymptomatic at the time of diagnosis, because the aneurysms are typically discovered incidentally on imaging studies. When an AA reaches medium to large size (>5cm), symptoms may manifest.

Symptoms for TAA are: patients may suffer a local mass effect, such as compression of the trachea or mainstem bronchus (if in the area of the lungs, will cause cough, shortness of breath, wheezing, or recurrent pneumonitis), compression of the esophagus (causing dysphagia), or compression of the recurrent laryngeal nerve (causing hoarseness). Chest pain, generally described as deep and aching or throbbing.

Symptoms of AAA are: pain in the chest, abdomen, lower back, or flank (over the kidneys). A pulsating feeling in the abdomen. A "cold foot" or a black or blue painful toe.

When a patient has abdominal aortic aneurysm of a substantial size, the patient may also have synchronous (at the same time) and metachronous (developed subsequently) thoracic aortic aneurysm. If causes and conditions are present to create an aneurysm in a large-medium size vessel in one place, you are more likely than those without those causes and conditions to have (or develop) another aneurysm somewhere. When a large abdominal aortic aneurysm is diagnosed, screening for TAA is usually recommended. The pressure from the medium to large aneurysm may also cause arterial dissection where the wall of the artery is tore, a "false lumen" forms within the wall of the artery and blood can leak into it - leading to rupture.

Both examples below ask the following questions:

1. Are AAA and TAA present? If yes, where are they? What is the diameter of the identified aneurysm?
2. In the presence of large AAA and TAA, arterial dissection is likely. If arterial dissection is observed, where is it? can you classify the dissection based on anatomy?

The figure below describes the general process flow from when a patient complains about the symptoms indicative of TAA and AAA to the diagnosis of TAA and AAA, followed by their subsequent evaluations. This is a summary of all the data collected.

The concept map below transforms the general process figure above into CDISC-compliant format. Note the (TST) and (RES) prefixes are done intentional in the map to show: measurement (--TEST) location vs result (--ORRES) location, respectively.

The patient had undergone a diagnostic intervention, during which a CT scan was done on the chest and abdomen of the subject. The CT scan created images of the thoracic and abdominal regions. An evaluator then reviewed the images of the thoracic region and abdominal region, to find whether aneurysms and arterial dissections are present and where they are located.

Case 1 - Subject has both TAA and AAA

The subject had CT scans performed on the chest and abdomen.

An evaluator examines the images of the thoracic and abdominal regions produced by the CT scan and decides whether TAA and AAA are present as well as their location. Modeling both TAA and AAA in the CV domain, note for viewing simplicity, some variables are omitted from the table below.

Case 2 - Subject has AAA but TAA is not found

The subject had a MRI performed on the torso (trunk).

The MRI scan produced images about the thoracic and abdominal regions of the subject. The evaluator then examined the MRI images of the thoracic region and abdominal region, and found the presence of a large AAA, but the absence of TAA.