Rupture risk higher in familial vs. sporadic unruptured intracranial aneurysms

A study published in Neurology found that the risk of rupture in familial unruptured intracranial aneurysms, or UIAs, is higher than in sporadic UIAs.

The longitudinal study assessed 3,089 UIAs across 2,297 patients and found that familial UIAs had 0.89% per person-year (95% CI, 0.45-1.59) rupture rate compared with 0.66% per person-year (95% CI, 0.48-1.89) for sporadic UIAs.

“In this individual patient data meta-analysis, we found a higher risk of rupture for familial compared to sporadic UIA, with a point estimate of a two and a half times higher risk, and a range from a 1.2 to 5 times higher risk when restricting our analysis to cohorts referring to affected first-degree relatives as parents, siblings and children in defining a positive family history,” Charlotte CM Zuurbier, MD, and colleagues wrote.

Zuurbier and colleagues collected and assessed studies covering the risk of UIA rupture published up to Dec. 1, 2020 through PubMed and Embase. Each study in the meta-analysis included a prospective study design; 50 or more patients with UIA; an assessment of the natural course of UIA; risk factors for aneurysm rupture, including family history for aneurysmal subarachnoid hemorrhage (aSAH) and UIA; and contained aneurysm rupture as an outcome. For each assessed study, the researchers requested data such as occurrence of rupture; date of rupture; data of a surgical or endovascular intervention; date of death; date of last follow-up assessment; and whether a patient was lost to follow-up for each patient.

Of the total number of patients with UIA, which spanned across Dutch, Japanese and Finish populations, 17% had a family history for aSAH and UIA. According to the study, patients with familial UIA were younger, more often smokers and less often had hypertension than sporadic UIA patients.

According to the researchers, rupture occurred in 53 patients with UIA, 96% of whom had a rupture of the largest aneurysm. The HR of patients with familial aneurysms compared with those with sporadic was 1.49 (95% CI, 0.73-3.07) in cohorts defining first-degree relatives as parents, children and siblings. The adjusted HR was 2.56 (95% CI, 1.18-5.56), with 10 patients with familial UIA experiencing ruptures and 41 sporadic UIA patients experiencing rupture.

“The higher incidence of aSAH in relatives of patients with familial aSAH is in part explained by a higher prevalence of UIA in these relatives,” Ruigrok and colleagues wrote. “Our study shows that a higher rupture risk of familial UIA also contributes to the higher incidence of aSAH in relatives with a family history of aSAH.”

According to the researchers, a more aggressive treatment approach should be given to patients with at least two first-degree relatives with UIA because of a higher risk of UIA rupture. More research is needed, however, on how higher rupture risk should influence screening strategies and cost effectiveness of UIA diagnosis and treatment, according to the study.

“Growth of UIA is associated with a higher risk of rupture,” Zuurbier and colleagues concluded. “Thus, a higher frequency of follow-up imaging may detect growth before rupture and provide the opportunity of targeted aggressive preventive treatment in familial UIA.”