This ten-year observational nationwide cohort of 79 935 patients reports for the first time the outcomes of patients from the French National Health data and represents one of the largest European retrospective study on AAA repair 6,8,9.
The proportion of patients who had EVAR/ open repair was balanced (approximatively 0.6) and was similar to the practice observed in other European countries 6,8. Ruptured AAA were most often treated using open repair (96.2% of cases). A population-based study in Finland between 2000 and 2014 revealed similar results, with 1627 treated with open repair over the 1687 ruptured AAA (96.4%). Several observational and multicenter randomized clinical trials have demonstrated improved outcomes after EVAR for ruptured AAA 3,12 and national trends in the United States confirmed that EVAR is increasingly used in the treatment of AAA rupture 13,14. Changes in the management of ruptured AAA are thus to be expected in France within the next decade.
The in-hospital mortality of patients operated for a non-ruptured AAA in France was 3.6%. A nationwide analysis of 84 631 patients in Germany reported comparable rate, with 3.3% of in-hospital mortality in patients operated for intact AAA 8. In case of aortic rupture, the in-hospital mortality following AAA repair was high (40%) and was concordant with other published studies 15,16. Age over 64 years old and female sex were significantly associated with the risk of AAA rupture, which is concordant with the current literature 5,17.
Interestingly, we found that the prevalence of cardiovascular comorbidities and metabolic disorders was significantly lower in patients with ruptured AAA compared to non-ruptured AAA. As a consequence, the odd ratio analysis showed that cardio-metabolic factors, were negatively associated with the risk of AAA rupture. The paradoxical negative association observed in our study could be explained by a delay in the diagnosis of AAA in patients who did not have cardio-metabolic comorbidities. It can be hypothesized that patients with comorbidities benefit from a closer follow-up and a screening of associated cardiovascular diseases. AAA in these patients may be discovered at earlier, asymptomatic and non-ruptured stage. On the other hand, it can be assumed that most of the patients who presented a rupture may have not been previously diagnosed for an AAA and may have not benefited from a systematic screening of cardiovascular comorbidities. It is thus possible that cardio-metabolic comorbidities may be underdiagnosed and underestimated in patients admitted for a ruptured AAA.
Our results underline the interest of population screening for AAA. Randomized clinical trials have demonstrated that ultrasound screening was effective to reduce AAA-related mortality, even in case of low prevalence of AAA 18–21. The review published by the National Institute for Health and Care Excellence (UK) regarding risk factors for predicting presence of an abdominal aortic aneurysm showed strong evidence that the risk of AAA increased with age 22. Although there was low or moderate quality evidence for cardiovascular diseases, hypertension and dyslipidemia, the committee agreed that taking into account risk factors could improve detection rates for opportunistic screening of AAA.
In case of AAA rupture, the death occurred more frequently during the hospital stay of the first AAA repair (1 873 over 2 425, 77.2%). Thus, it is not surprising that the in-hospital mortality was significantly lower in patients with cardio-metabolic comorbidities compared to those who did not, given the fact that they had a lower proportion of ruptured AAA. The same trend was observed for the 1-year mortality. As recommended by the Society of Vascular Surgery, patients with known cardio-metabolic comorbities benefit from a thorough pre-operative evaluation and a close follow-up, which could partly contribute to limit the mortality 3.
However, our results on total long-term mortality rather suggested a worse prognosis in patients with cardio-metabolic comorbidities. Other studies have also identified heart failure, ischemic heart disease, cerebrovascular disease and diabetes as risk factors of mortality following elective AAA repair 23,24. Nevertheless, we found in our cohort that the total mortality was significantly lower in patients presenting dyslipidemia, obesity, SAOS or smoking compared to those who did not have these comorbidities. Note that non-smokers were significantly older than smokers and could explain this result. Johal et al. recently aimed to examine patterns of 10-year survival after elective repair of unruptured AAA and investigated the survival among patients of different age and different co-morbidity score profiles from the English National Health register 25. The long-term survival patterns after elective open repair and EVAR for unruptured AAA varied markedly across patients with different age and co-morbidity profiles. This underlines the complex impact of comorbidities on the post-operative outcomes and suggests that multiparametric predictive scores would be of interest.
The survival analysis after discharge from the first AAA repair revealed that aging, the presence of an aortic rupture, in-hospital readmission at 30 days, chronic respiratory and kidney diseases were predictive factors of post-operative mortality. These results are concordant with a meta-analysis including 45 studies investigating factors influencing survival following AAA repair 26. End stage renal disease, chronic obstructive pulmonary disease, age, cardiac failure, cerebrovascular diseases were associated with poor long-term survival. In our cohort, we found that in-hospital mortality was higher in patients who had open repair, and could be partially explained by the higher proportion of ruptured AAA. However, EVAR was associated with increased risk of long-term mortality after discharge from the hospital. Randomized clinical trials have suggested that EVAR was associated with early survival gain, while open repair showed similar or late survival benefits 27–30.
This a retrospective observational study based on electronic administrative database and the results may depend on the coding system. Nevertheless, the French National insurance information system uses codes based on standardized definitions. Data are extracted by medical doctors and certified reviewers and the quality of the French National electronic health data is audited annually by experts. The medical treatments of patients were not available and the deaths occurring in the absence of hospitalization could not be recorded in the database. However, given the age of the population and the total mortality rate (21.3%), it can be assumed that most of the patients presenting a severe and potentially life-threatening disease may have been hospitalized. Although the results could not be classified according to the severity of the comorbidities, the size of the cohort allowed adequate statistical power to investigate the differences among the groups.