Bicuspid Aortic Valve Patients at Increased Risk for Brain Aneurysm

May 4, 2010 — Patients with the most common congenital heart defect are also more likely to develop an intracranial aneurysm, warn researchers.
They report close to 10% of bicuspid aortic valve patients in their new study had an aneurysm.
"While more research needs to be done to confirm the results, these findings show a significant increased risk of brain aneurysms in people with bicuspid aortic valves," lead investigator Wouter Schievink, MD, from Cedars-Sinai Medical Center in Los Angeles, California, said in a news release.
Up to 2% of the population is born with the congenital heart defect, so the investigators suggest the implications of this study could be important.
Their work appears in the May 4 issue of Neurology. Investigators conducted a case-control study of 291 people. Patients underwent magnetic resonance or computed tomography angiography of the brain.
The researchers report the frequency of intracranial aneurysm among bicuspid aortic valve patients is similar to that found in patients with other systemic disorders that carry an increased risk, such as autosomal dominant polycystic kidney disease or coarctation of the aorta.
Table. Rate of Intracranial Aneurysms

Population	No. (%) of Aneurysms	95% Confidence Interval, %	P Value
Bicuspid aortic valve patients (n = 61)	6 (9.8)	2.4 – 17.3	.0012
Control patients (n = 291)	3 (1.1)	0 – 2.2	.0012

Risk factors for intracranial aneurysm, such as female sex and advanced age, were more common in the control group (P = .02 and P = .003).
In the bicuspid aortic valve patients, Dr. Schievink reports no significant differences in age, sex, smoking, arterial hypertension, alcohol use, aortic diameter, or frequency of aortic coarctation between those who had an aneurysm and those who did not.
Dr. Schievink points out that bicuspid aortic valve problems tend to cluster in families. He notes that mutations in NOTCH1 have been reported in some, but the defect is probably genetically heterogeneous.
Genetic factors also appear to factor into intracranial aneurysm. Single-nucleotide polymorphisms on the 9p locus have been linked to aneurysm and other arterial diseases.
In a genome-wide association study, investigators led by Kaya Bilguvar, MD, from Yale University in New Haven, Connecticut, added chromosomes 2q and 8q to the list. They reported increased odds ratios for intracranial aneurysm of 1.24 to 1.36 (Nat Genet. 2008;40:1472-1477).
Dr. Schievink acknowledges his new study is too small to draw any firm conclusions and calls for additional investigation.
The researchers have disclosed no relevant financial relationships.