An abdominal aortic aneurysm (AAA) is a localized dilatation of the infrarenal aorta. AAA is a multifactorial disease, and genetic and environmental factors play a part; smoking, male sex and a positive family history are the most important risk factors, and AAA is most common in men >65 years of age. AAA results from changes in the aortic wall structure, including thinning of the media and adventitia due to the loss of vascular smooth muscle cells and degradation of the extracellular matrix. If the mechanical stress of the blood pressure acting on the wall exceeds the wall strength, the AAA ruptures, causing life-threatening intra-abdominal haemorrhage — the mortality for patients with ruptured AAA is 65–85%. Although AAAs of any size can rupture, the risk of rupture increases with diameter. Intact AAAs are typically asymptomatic, and in settings where screening programmes with ultrasonography are not implemented, most cases are diagnosed incidentally. Modern functional imaging techniques (PET, CT and MRI) may help to assess rupture risk. Elective repair of AAA with open surgery or endovascular aortic repair (EVAR) should be considered to prevent AAA rupture, although the morbidity and mortality associated with both techniques remain non-negligible.

Background: A general abdominal aortic aneurysm (AAA) screening program, targeting 65-year-old men, has gradually been introduced in Sweden since 2006 and reached nationwide coverage in 2015. The aim of this study was to determine the outcome of this program. Methods: Data on the number of invited and examined men, screening-detected AAAs, AAAs operated on, and surgical outcome were retrieved from all 21 Swedish counties for the years 2006 through 2014. AAA-specific mortality data were retrieved from the Swedish Cause of Death Registry. A linear regression analysis was used to estimate the effect on AAA-specific mortality among all men ≥65 years of age for the observed time period. The long-term effects were projected by using a validated Markov model. Results: Of 302 957 men aged 65 years invited, 84% attended. The prevalence of screening-detected AAA was 1.5%. After a mean of 4.5 years, 29% of patients with AAA had been operated on, with a 30-day mortality rate of 0.9% (1.3% after open repair and 0.3% after endovascular repair, P <0.001). The introduction of screening was associated with a significant reduction in AAA-specific mortality (mean, 4.0% per year of screening, P =0.020). The number needed to screen and the number needed to operate on to prevent 1 premature death were 667 and 1.5, respectively. With a total population of 9.5 million, the Swedish national AAA-screening program was predicted to annually prevent 90 premature deaths from AAA and to gain 577 quality-adjusted life-years. The incremental cost-efficiency ratio was estimated to be €7770 per quality-adjusted life-years. Conclusions: Screening 65-year-old men for AAA is an effective preventive health measure and is highly cost-effective in a contemporary setting. These findings confirm the results from earlier randomized controlled trials and model studies in a large population-based setting of the importance for future healthcare decision making.

Identification and treatment of abdominal aortic aneurysm (AAA) remain among the most prominent challenges in vascular medicine. MicroRNAs (miRNAs) are crucial regulators of cardiovascular pathology and represent intriguing targets to limit AAA expansion. Here we show, by using two established murine models of AAA disease along with human aortic tissue and plasma analysis, that miR-24 is a key regulator of vascular inflammation and AAA pathology. In vivo and in vitro studies reveal chitinase 3-like 1 (Chi3l1) to be a major target and effector under the control of miR-24, regulating cytokine synthesis in macrophages as well as their survival, promoting aortic smooth muscle cell migration and cytokine production, and stimulating adhesion molecule expression in vascular endothelial cells. We further show that modulation of miR-24 alters AAA progression in animal models, and that miR-24 and CHI3L1 represent novel plasma biomarkers of AAA disease progression in humans.

Background: No reliable comparative data exist between open repair (OR) and endovascular aneurysm repair (EVAR) for mycotic abdominal aortic aneurysms (MAAAs). This nationwide study assessed outcomes after OR and EVAR for MAAA in a population-based cohort. Methods: All patients treated for MAAAs in Sweden between 1994 and 2014 were identified in the Swedish vascular registry. The primary aim was to assess survival after MAAA with OR and EVAR. Secondary aims were analyses of the rate of recurrent infections and reoperations, and time trends in surgical treatment. Survival was analyzed using Kaplan-Meier and log-rank tests. A propensity score–weighted correction for risk factor differences in the 2 groups was performed, including the operation year to account for differences in treatment and outcomes over time. Results: We identified 132 patients (0.6% of all operated abdominal aortic aneurysms in Sweden). Mean age was 70 years (standard deviation, 9.2), and 50 presented with rupture. Survival at 3 months was 86% (95% confidence interval, 80%–92%), at 1 year 79% (72%–86%), and at 5 years 59% (50%–68%). The preferred operative technique shifted from OR to EVAR after 2001 (proportion EVAR 1994–2000 0%, 2001–2007 58%, 2008–2014 60%). Open repair was performed in 62 patients (47%): aortic resection and extra-anatomic bypass (n=7), in situ reconstruction (n=50), and patch plasty (n=3); 2 patients died intraoperatively. EVAR was performed in 70 patients (53%): standard EVAR (n=55), fenestrated/branched EVAR (n=8), and visceral deviation with stent grafting (n=7); no deaths occurred intraoperatively. Survival at 3 months was lower for OR than for EVAR (74% versus 96%, P <0.001), with a similar trend present at 1 year (73% versus 84%, P =0.054). A propensity score–weighted risk-adjusted analysis confirmed the early better survival associated with EVAR. During median follow-up of 36 and 41 months for OR and EVAR, respectively, there was no difference in long-term survival (5 years 60% versus 58%, P =0.771), infection-related complications (18% versus 24%, P =0.439), or reoperation (21% versus 24%, P =0.650). Conclusion: This study demonstrates a paradigm shift in treatment of MAAA in Sweden, with EVAR being the preferred treatment modality. EVAR was associated with improved short-term survival in comparison with OR, without higher associated incidence of serious infection-related complications or reoperations.

As large population-based studies of aortic dissection are lacking, the incidence numbers and knowledge about time-trends and sex differences are uncertain. The objective was to describe incidence, temporal trends and outcome of aortic dissection with particular emphasis on sex differences. During the study period 2002–2016, 8057 patients in Sweden were diagnosed with aortic dissection, identified from the National Patient Register and the Cause of Death Register. A total of 5757 (71%) patients were hospitalized, whereas 2300 (29%) patients were deceased without concurrent hospital stay. The annual incidence was 7.2 per 100 000 (9.1 in men and 5.4 in women), decreasing over time in men (P = 0.005). Mean age in the hospitalized patients was 68 years (SD 13), 2080 (36%) were women. Within the first 14 days after onset, 1807 patients (32%) underwent surgical repair. The proportion of surgically treated increased from the 5-year period 2002–2006 to 2012–2016 [27% vs. 35%, odds ratio (OR) 1.61, 95% confidence interval (CI) 1.39–1.86; P < 0.001]. In hospitalized patients, 30-day mortality decreased between the same periods (26% vs. 21%, OR 0.68, 95% CI 0.59–0.80; P < 0.001). Long-term mortality decreased as well (hazard ratio 0.74, 95% CI 0.67–0.82; P < 0.001). Women had higher 30-day mortality than men after acute repair, a sex difference that remained after age adjustment (17% vs. 12%, OR 1.38, 95% CI 1.04–1.82; P = 0.006). This population-based study detected a higher incidence of aortic dissection than prior reports, but a decreasing incidence in men. Surgical therapy was increasingly used and with more favourable outcome but was less frequently offered to elderly patients. The sustained sex differences regarding both incidence and outcome require further attention.