Familial Abdominal Aortic Aneurysms Don't Occur Earlier in Life, Neither do they Progress More Rapidly – Observations from Two Population Based Screening Trials

Abstract

Introduction: Familial Abdominal Aortic Aneurysm (fAAA) is believed to develop earlier in life and progress faster than non-fAAAs. Consequently, current European guidelines recommend screening of first degree relatives to AAA patients from the age of 50. But this recommendation is based on only a few small sized studies. The objective of this study was to compare patient age and size of AAA at diagnosis, and progression of fAAA versus non-fAAAs in two large population-based screening trials. Methods: Study design: Combined population-based cross-sectional and cohort study. Materials: 1099 male participants screened positive for AAA in the VIVA- and DANCAVAS trials. Of these, follow-up data regarding growth rate, the need for aneurysmal repair and death were available in the 617 cases found through the VIVA-study. Using two nationwide registers, the national patient register registering diagnosis and performed procedures, the cause of death register registering causes of death. Ultrasound- and CT-scans were used to determine the maximum abdominal aortic diameter. Data regarding family history, traditional risk factors, prior CVD and medication were obtained by questionnaire at baseline. Difference between the two groups were tested using Wilcoxons ranksum test. Multiple linear regression and multiple cox-regression were used to adjust for potential confounding from age, comorbidities and medication. Finally, using the National Patient Register and Cause of Death register, we investigated the number of patients nationwide diagnosed with a ruptured AAA in different age groups between 1996 and 2016. Results: Of the 1099 AAAs, 77 (7.0%) were fAAAs. We observed no significant difference in age between the two groups, mean age being 70.2 and 69.9 years in the fAAA group and the non-fAAA group, respectively (p=0.99). We did not find any significant difference in median size of the aneurysms (fAAA=38.6 mm versus non-fAAA=36.4 mm. p=0.48). No significant difference was found in the growth rate of the aneurysms (adj. coef. -0.26 cm/y. 95% CI: -1.2 to 0.69), nor in the need for aneurysmal repair (adj. HR=1.10 95% CI: 0.67-1.78) or mortality (Adj. HR=0.43. 95 % CI: 0.16-1.19). Using data from the national patient register and cause of death register we found that 3.9 % percent of aneurysms ruptured before the age of 60 years old and 10.5 % before the age of 65 years. Conclusion: In two large population-based screening trials we found no evidence corroborating the hypothesis that fAAAs develop earlier in life or shows a more aggressive disease progression than non-fAAAs. This questions the current guidelines of screening relatives to AAA patients from a much earlier age than the rest of the population. Disclosure: Nothing to disclose