Concordance in Aneurysm Size at Time of Rupture in Familial Intracranial Aneurysms

BACKGROUND AND PURPOSE—Intracranial aneurysm (IA) size and location are important determinants of aneurysm rupture risk. In familial IAs there is concordance of location; however, if such concordance exists for size is unknown. We analyzed the concordance of aneurysm size at time of rupture in familial IAs. METHODS—In pairs of affected relatives with aneurysmal subarachnoid hemorrhage, the ratio between the largest and the smallest aneurysm size at time of rupture was calculated. We also compared the proportion of families in which both IAs ruptured at a size < or ≥7 mm with the proportion of families in which one IA ruptured at 1.2, and 12 (17%) had a ratio ≥3. We found no difference between the proportion of families (n=31; 49%) who both had IA at time of rupture