# Risk factor analysis of growing unruptured intracranial aneurysms: A single center cohort study

## TL;DR

This study identifies risk factors for growth of unruptured brain aneurysms, including location, size, and high blood pressure.

## Contribution

The study provides new evidence on specific risk factors for aneurysm growth using a large single-center cohort.

## Key findings

- Posterior circulation aneurysms are twice as likely to grow compared to others.
- Each additional millimeter in initial aneurysm size increases growth risk by 10%.
- Arterial hypertension increases growth risk by 60%.

## Abstract

Intradural unruptured intracranial aneurysms (UIA) can rupture and lead to subarachnoid hemorrhage. Previous studies suggest aneurysm growth being a strong risk factor for rupture. The natural history and the individual risk of growth of aneurysms remain controversial.

To analyze the time to growth and identify risk factors associated with growth of UIAs.

Prospectively collected data of 588 patients with a total of 858 UIAs followed up by imaging were analyzed. Patients and aneurysms were categorized in a growing or a stable cohort. Logistic and survival analyses were used to assess potential factors associated with UIA growth.

During a median follow-up of 3.4 years (IQR 1.3 – 6.6 years), 112 (13.1%) out of the 858 UIAs showed an increase in size or a change of morphology. Posterior circulation UIAs (OR 2.01 (1.15 – 3.52), p = 0.01), aneurysm size at diagnosis (OR 1.10 (1.04 – 1.16) per mm, p = 0.002) and arterial hypertension (OR 1.60 (1.03 – 2.49), p = 0.04) were significantly associated with growth. Survival analyses confirmed a time-dependent association with growth for posterior circulation UIAs (HR 3.9 (1.74 – 8.75), p = 0.002) and aneurysm size (HR 1.22 (1.13 – 1.31), p < 0.0001).

UIA location in the posterior circulation, a larger size at diagnosis and the presence of arterial hypertension are significant risk factors associated with UIA growth.

•Logistic and survival analysis of n = 588 patients with 858 aneurysms.•Posterior circulation aneurysms at a higher risk of growth.•A larger aneurysm size at diagnosis increases the risk of growth.•Presence of arterial hypertension associated with aneurysmal growth.

Logistic and survival analysis of n = 588 patients with 858 aneurysms.

Posterior circulation aneurysms at a higher risk of growth.

A larger aneurysm size at diagnosis increases the risk of growth.

Presence of arterial hypertension associated with aneurysmal growth.