From the Research
Posterior communicating artery (PCA) aneurysms are primarily caused by a combination of genetic, environmental, and hemodynamic factors, including hypertension, smoking, family history, and connective tissue disorders, as well as altered blood flow patterns, such as those seen in patients with subclavian artery occlusion 1. The causes of PCA aneurysms can be multifactorial, involving both intrinsic and extrinsic factors. Intrinsic factors include genetic predisposition, with some studies suggesting a higher incidence of aneurysms in patients with a family history of aneurysms or connective tissue disorders 2. Extrinsic factors, on the other hand, may include environmental influences such as smoking and hypertension, which can increase the risk of aneurysm formation and rupture 1. Some studies have also suggested that hemodynamic factors, such as altered blood flow patterns, may play a role in the formation and rupture of PCA aneurysms. For example, a study published in 2005 found that a patient with a subclavian artery occlusion developed a "high flow" true posterior communicating artery aneurysm due to the altered hemodynamic effects of the occlusion 3. Other factors that may contribute to the formation and rupture of PCA aneurysms include the size and shape of the aneurysm, as well as the presence of other intracranial aneurysms. A study published in 2014 found that patients with ruptured PCA aneurysms were more likely to have aneurysms with a lateral direction of the aneurysmal dome, bleb formation, and a larger size (> 7 mm in diameter) or a higher dome-to-neck ratio (> 2.0) 1. It is also worth noting that the most recent and highest quality study on this topic, published in 2021, found that endovascular treatment of PCA aneurysms can be effective in preventing rupture or rebleeding, with a high occlusion rate and relatively low risk of complications 4. Key factors that contribute to the development of PCA aneurysms include:
- Genetic predisposition
- Environmental factors, such as smoking and hypertension
- Hemodynamic factors, such as altered blood flow patterns
- Size and shape of the aneurysm
- Presence of other intracranial aneurysms
- Age, with younger patients more likely to experience rupture 1