**2.1. Pathophysiology**

An aneurysm may be true aneurysm where all the three vessel layers are involved or false where the endothelium or even the media may be disrupted leading to an intramural hematoma or hemorrhage (5). The most common etiology is atherosclerosis but other causes include formation of true or false aneurysms post angioplasty, true aneurysm formation at

© 2012 Kang and Kang, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

the site of a venous valve or false aneurysms at the site of suture rupture or false aneurysm from infectious etiology (5). Aneurysms may result from chronic steroid use or unsuspected harvesting of varicose veins (5).

The true aneurysms are fusiform and often in the middle of the graft and the false aneurysms are saccular and often at the origin of the graft but the aneurysms can be seen anywhere (4,5). Inflammatory causes as in aneurysms elsewhere may also be considered but lack any specific anti-inflammatory therapy (7).

#### **2.1.1. Symptoms**

True aneurysms are often asymptomatic in about half of the patients that present to medical attention and are discovered incidentally on imaging studies (5). They are seen most often in left anterior descending artery venous bypasses followed by right coronary and circumflex artery bypasses, respectively.

A triad of chest pain, mediastinal enlargement and previous coronary bypass may raise suspicion of a saphenous vein graft aneurysm (4). The symptoms at presentation are usually angina, myocardial infarction, congestive heart failure or variety of symptoms from graft occlusion, embolization, fistula formation or compression of surrounding structures (4,5). False aneurysms are usually symptomatic, however. Only minority of patients with false aneurysms is asymptomatic and the majority of the patients with false aneurysm present with the same symptoms as true aneurysms but the incidence of rupture is higher than with true aneurysms (5). Rupture of the aneurysm into the lung may lead to hemoptysis and into a cardiac chamber can lead to a fistula (8,9,10). Also, compression of left internal mammary artery graft by an aneurysm was recently described (9).

**Figure 1.** Multiple aneurysms and pseuodaneuyrsms with a narrow neck.

**Figure 2.** Coil embolization of a large pseudoaneurysm on the patient above.

harvesting of varicose veins (5).

**2.1.1. Symptoms** 

artery bypasses, respectively.

lack any specific anti-inflammatory therapy (7).

artery graft by an aneurysm was recently described (9).

**Figure 1.** Multiple aneurysms and pseuodaneuyrsms with a narrow neck.

the site of a venous valve or false aneurysms at the site of suture rupture or false aneurysm from infectious etiology (5). Aneurysms may result from chronic steroid use or unsuspected

The true aneurysms are fusiform and often in the middle of the graft and the false aneurysms are saccular and often at the origin of the graft but the aneurysms can be seen anywhere (4,5). Inflammatory causes as in aneurysms elsewhere may also be considered but

True aneurysms are often asymptomatic in about half of the patients that present to medical attention and are discovered incidentally on imaging studies (5). They are seen most often in left anterior descending artery venous bypasses followed by right coronary and circumflex

A triad of chest pain, mediastinal enlargement and previous coronary bypass may raise suspicion of a saphenous vein graft aneurysm (4). The symptoms at presentation are usually angina, myocardial infarction, congestive heart failure or variety of symptoms from graft occlusion, embolization, fistula formation or compression of surrounding structures (4,5). False aneurysms are usually symptomatic, however. Only minority of patients with false aneurysms is asymptomatic and the majority of the patients with false aneurysm present with the same symptoms as true aneurysms but the incidence of rupture is higher than with true aneurysms (5). Rupture of the aneurysm into the lung may lead to hemoptysis and into a cardiac chamber can lead to a fistula (8,9,10). Also, compression of left internal mammary

**Figure 3.** Intravascular ultrasound showing pseudoaneurysm at the 2O'clock position with disrupted endothelium

**Figure 4.** True aneurysm from 4 to 6O'clock position on intravascular ultrasound

**Figure 4.** True aneurysm from 4 to 6O'clock position on intravascular ultrasound

**Figure 5.** Chest CT scan image of a large leaking aneurysm compressing the right atrium

#### **3. Signs**

A variety of signs related to the pathophysiology at the time of presentation may be seen. A pulsatile mass on palpation or ischemia causing a gallop rhythm may be noted. If the rupture of the aneurysm occurs then murmurs related to fistula formation or shock secondary to bleeding or compression may be evident (4,5,8,9,10).
