Sources: EJVES Aug 2015
Many definitions exist, the easiest is when at least one first-degree relative (parent, sibling, offspring) is diagnosed with an aortic aneurysm. Based upon family history review, the proportion of patients with AAA with familial AAA is around 13% (range 6–36%).2 Ultrasound screening of the relatives of those with AAAs suggests a prevalence of 17% (range 9–29%) in men and 4% (range 0–11%) in women.
Clinical phenotypes – Studies suggest that patients with familial AAA are significantly more likely to be female, younger, have fewer cardiovascular risk factors (e.g., hypertension and diabetes mellitus), and possibly have a lower carotid intima-media thickness. Studies also show a high rate of thoracic aortic aneurysms and an increased rate of bilateral iliac aneurysms in patients with familial AAA. Relatives of patients with familial AAA also appear to have increased aortic diameters.
In any case, additional environmental effects, such as smoking, hypertension and hypercholester- olemia could enhance the risk of aneurysm formation and therefore explain the variability in expression of the disease.
Most accepted genetic aortic aneurysm syndromes are caused by defects in genes involved in the transforming growth factor-b pathway,8 and are associated with syn- dromes like Marfan disease and LoeyseDietz syndrome.
Until now, family studies have detected a linkage with the 19q13 and 4q31 regions in the genome but without identifying specific genes in these regions. A genome- wide single nucleotide polymorphism with AAA include DAB2IP, LRP1, LDLR, ANRIl, and SORT1.10 Having one of these alleles results in an additional `20% risk for devel- oping AAA; however, the causal relationship of these poly- morphisms still needs to be elucidated.
ACTION PLAN –
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The present American College of Cardiology/American Heart Association guidelines recom- mend ultrasound screening for male relatives aged 60 years or older, while the European Society for Vascular Surgery guidelines recommend ultrasound screening of both male and female relatives aged >50 years who have a family history of AAA.
It is not known whether endovascular aneurysm repair (EVAR) or open repair (OR) is the optimal treatment for patients with familial AAA. Only very limited data are available; however, as patients with familial AAA tend to be younger, they may benefit from OR, which carries a lower secondary intervention risk with time.