Length of abdominal aortic aneurysm and incidence of endoleaks type II after endovascular repair

Endovascular Treatment of Abdominal Aortic Aneurysm: Impact of Diabetes on Endoleaks and Reintervention

Background: Diabetes has a protective effect on abdominal aortic aneurysms (AAAs); however, there are contrasting reports on the impact of diabetes on endovascular aortic repair (EVAR) outcomes, endoleaks (ELs) being the major negative outcome. The present study characterizes ELs and their outcomes in AAA patients, diabetic or not. Methods: This single-center, retrospective, comparative study was carried out on 324 AAA patients who underwent elective EVARs between 2007 and 2016 at the University Hospital of Liège (Belgium). The primary endpoint was the incidence and effect of ELs on the evolution of the aneurysmal sac; the secondary endpoints were surgical reintervention and mortality rate. Diabetic and non-diabetic patients were compared with respect to various risk factors by logistic regression, while a Cox regression was used to analyze survival. Results: In AAA patients meeting the inclusion criteria (n = 248), 23% were diabetic. EL incidence was comparable (p = 0.74) in diabetic (38.7%) vs. non-diabetic (43.9%) patients. EL risk factors were age (HR = 1.04, p = 0.014) and fibrate intake (HR = 3.12, p = 0.043). A significant association was observed between ELs and aneurysm sac enlargement (p < 0.001), regardless of group (p = 0.46). Aneurysm sac regression per month for non-diabetic patients was -0.24 ± 0.013, while for diabetics it was -0.18 ± 0.027 (p = 0.059). Dyslipidemia (HR = 3.01, p = 0.0060) and sulfonylureas (HR = 8.43, p = 0.043) were associated with shorter EL duration, while diabetes (HR = 0.080, p = 0.038) and beta blockers (HR = 0.46, p = 0.036) were associated with longer EL duration. The likelihood of reoperation decreased with more recent surgery (OR = 0.90, p = 0.040), regardless of diabetic status. All-cause mortality was higher for the non-diabetic group (45.5% vs. 26.3%, p = 0.0096). Conclusions: Endoleak occurrence is a known risk factor for sac expansion. In diabetic patients, endoleaks lasted longer, and regression of the aneurysm sac tended to be slower. The number and type of reintervention was not related to the diabetic status of AAA patients, but overall survival was higher in patients with diabetes.

Arterial pulse wave propagation across stenoses and aneurysms: assessment of one-dimensional simulations against three-dimensional simulations and in vitro measurements

One-dimensional (1-D) arterial blood flow modelling was tested in a series of idealized vascular geometries representing the abdominal aorta, common carotid and iliac arteries with different sizes of stenoses and/or aneurysms. Three-dimensional (3-D) modelling and in vitro measurements were used as ground truth to assess the accuracy of 1-D model pressure and flow waves. The 1-D and 3-D formulations shared identical boundary conditions and had equivalent vascular geometries and material properties. The parameters of an experimental set-up of the abdominal aorta for different aneurysm sizes were matched in corresponding 1-D models. Results show the ability of 1-D modelling to capture the main features of pressure and flow waves, pressure drop across the stenoses and energy dissipation across aneurysms observed in the 3-D and experimental models. Under physiological Reynolds numbers (Re), root mean square errors were smaller than 5.4% for pressure and 7.3% for the flow, for stenosis and aneurysm sizes of up to 85% and 400%, respectively. Relative errors increased with the increasing stenosis and aneurysm size, aneurysm length and Re, and decreasing stenosis length. All data generated in this study are freely available and provide a valuable resource for future research.

Perioperative factors associated with aneurysm sac size changes after endovascular aneurysm repair

PURPOSE

To identify the perioperative factors associated with aneurysm size changes after endovascular aortic aneurysm repair (EVAR).

METHODS

Between August, 2008 and December, 2014, 187 patients underwent EVAR treatment in our institution. The subjects of this study were 135 of these patients without peripheral artery disease, who were followed up with computed tomography (CT) for 3 years. Significant aneurysm size change was defined as sac size change of more than 5 mm from the baseline.

RESULTS

Sac enlargement was identified in 25 patients (18.5%) and sac shrinkage was identified in 59 (43.7%) patients. The factors associated with sac enlargement were postoperative pulse wave velocity (OR: odds ratio 3.80, p = 0.047), prevalence of a type 2 endoleak 1 week after surgery (OR 4.26, p = 0.022), inner diameter (OR 1.10, p = 0.005), and distance from the lower renal artery to the terminal aorta (OR 1.05, p = 0.017). The factors associated with sac shrinkage were prevalence of a type 2 endoleak (OR 0.09, p < 0.001) and preoperative pulse wave velocity (OR 0.32, p = 0.022). The factors independently associated with type 2 endoleak were the use of an Excluder device (OR 3.99, p = 0.002) and the length of the aneurysm (OR 1.02, p = 0.027).

CONCLUSION

Inner diameter, treatment length, perioperative pulse wave velocity, and type 2 endoleak were associated with sac size changes after EVAR.

Prevalence and risk factors of type II endoleaks after endovascular aneurysm repair: A meta-analysis

Objectives

This systematic review and meta-analysis aims to determine the current evidence on risk factors for type II endoleaks after endovascular aneurysm repair (EVAR).

Materials and methods

A systematic literature search was carried out for studies that evaluated the association of demographic, co-morbidity, and other patient-determined factors with the onset of type II endoleaks. Pooled prevalence of type II endoleaks after EVAR was updated.

Results

Among the 504 studies screened, 45 studies with a total of 36,588 participants were included in this review. The pooled prevalence of type II endoleaks after EVAR was 22% [95% confidence interval (CI), 19%–25%]. The main factors consistently associated with type II endoleaks included age [pooled odds ratio (OR), 0.37; 95% CI, 0.31–0.43; P<0.001], smoking (pooled OR, 0.71; 95% CI, 0.55–0.92; P<0.001), patent inferior mesenteric artery (pooled OR, 1.98; 95% CI, 1.06–3.71; P = 0.012), maximum aneurysm diameter (pooled OR, 0.23; 95% CI, 0.17–0.30; P<0.001), and number of patent lumbar arteries (pooled OR, 3.07; 95% CI, 2.81–3.33; P<0.001). Sex, diabetes, hypertension, anticoagulants, antiplatelet, hyperlipidemia, chronic renal insufficiency, types of graft material, and chronic obstructive pulmonary diseases (COPD) did not show any association with the onset of type II endoleaks.

Conclusions

Clinicians can use the identified risk factors to detect and manage patients at risk of developing type II endoleaks after EVAR. However, further studies are needed to analyze a number of potential risk factors.

Endovascular Management of Abdominal Aortic Aneurysms: the Year in Review

OPINION STATEMENT

Endovascular aneurysm repair (EVAR) has become the predominant method of treatment for abdominal aortic aneurysms (AAA). The use of conscious sedation with local anesthesia and percutaneous femoral access has further decreased the morbidity of the procedure. Current devices can more effectively manage increasingly "hostile" aneurysm necks, while chimney grafts or dedicated fenestrated stent-grafts can be used for juxta-renal disease with favorable results. However, endovascular repair does present a new set of challenges, and endoleaks remain an area of concern. While there is general consensus that type I and type III endoleaks require treatment, type II endoleaks are the topic of ongoing research and debate. Development of devices and techniques to prevent and treat endoleak continues to progress. Advances in contrast-enhanced ultrasound are reducing reliance on computed tomography for post-operative monitoring. This is an important step in this population at high risk for the development of kidney failure. Despite these many innovations, further research is needed to optimize the care of patients with AAA.