Morphology and Hemodynamics in Isolated Common Iliac Artery Aneurysms Impacts Proximal Aortic Remodeling.

Objective- Isolated common iliac artery aneurysms (CIAA) are rare. Their prognosis and influence on aortoiliac blood flow and remodeling are unclear. We evaluated the hypotheses that morphology at and distal to the aortic bifurcation, together with the associated hemodynamic changes, influence both the natural history of CIAA and proximal aortic remodeling. Approach and Results- Twenty-five isolated CIAAs (15 intact, 10 ruptured), in 23 patients were reconstructed and analyzed with computational fluid dynamics: all showed abnormal flow. Then we studied a series of 24 hypothetical aortoiliac geometries in silico with varying abdominal aortic deflection and aortic bifurcation angles: key findings were assessed in an independent validation cohort of 162 patients. Wall shear stress in isolated unilateral CIAAs was lower than the contralateral common iliac artery, 0.38±0.33 Pa versus 0.61±0.24 Pa, inversely associated with CIAA diameter ( P<0.001) and morphology (high shear stress in variants distal to a sharp kink). Rupture usually occurred in regions of elevated low and oscillatory shear with a wide aortic bifurcation angle. Abdominal aortas deflected towards the CIAA for most unilateral isolated CIAAs (14/21). In silico, wider bifurcation angles created high focal regions of low and oscillatory shear in the common iliac artery. The associations of unilateral CIAA with aortic deflection and common iliac artery diameter with bifurcation angle were confirmed in the validation cohort. Conclusions- Decreasing wall shear stress is strongly associated with CIAA progression (larger aneurysms and rupture), whereas abnormal blood flow in the CIAA seems to promote proximal aortic remodeling, with adaptive lateral deflection of the abdominal aorta towards the aneurysmal side.

Single-Center Experience Following the Introduction of a Percutaneous Endovascular Aneurysm Repair First Approach.

We evaluated our experience following the introduction of a percutaneous endovascular aneurysm repair (pEVAR) first approach using Perclose Proglide assessing efficacy, complications, and identification of factors that could predict failure. A retrospective cohort study on patients over a 2-year period following the introduction of a pEVAR first approach was performed. The primary end point was defined as successful deployment and access site hemostasis. Percutaneous EVAR was technically successful in 41 (77.4%) of 53 patients and 83 (86.5%) of 96 access sites. Factors associated with failure were smaller common femoral artery (CFA) diameter ( P = .045) and CFA circumferential calcification of greater than 50% ( P = .0001). The incidence of access site infection was significantly higher in the failure group ( P = .008) as was procedure duration ( P = .026). Percutaneous EVAR first approach must be introduced with caution. Percutaneous EVAR failure occurs more often in patients with unfavorable access site anatomy. Success rate can be improved with careful patient selection.

Reintervention following endovascular abdominal aneurysm repair is uncommon after five-years: results of greater than a decade follow-up.

BACKGROUND: Endovascular aneurysm repair offers improved perioperative morbidity and mortality compared to open repair, counterbalanced by a higher incidence of graft-related complications and re-interventions. Randomized studies comparing EVAR to open repair are yet to report greater than ten-year outcomes. This study reports the outcomes of patients who underwent EVAR greater than ten years ago. METHODS: Retrospective review of prospectively collected data of all patients who underwent EVAR between 1997 and 2001, supplemented with case-note review, interrogation of imaging and correspondence with general practitioners and coroners' offices. RESULTS: Fifty-eight patients underwent EVAR. Technical success was 100% and 30-day mortality was 0%. The re-intervention rate was 27.3%, including 5 elective open conversions, 2 emergency open repairs, 5 embolizations of endoleaks and 3 extensions. Median time to primary re-intervention was 30 months (1-98). Four graft related complications occurred beyond 5 years however only one reintervention was performed beyond this time point. Four patients died from ruptured AAA. CONCLUSIONS: Stable long-term aneurysm exclusion was achieved in the majority of patients with most re-interventions occurring early in the follow up period. Whilst life-long surveillance should be continued, these data raise the question of the appropriate duration of CT surveillance and suggest that EVAR should be considered for patients with longer life expectancy and favourable anatomy who traditionally would have undergone open repair.

Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial.

OBJECTIVE: To assess whether a strategy of endovascular repair (if aortic morphology is suitable, open repair if not) versus open repair reduces early mortality for patients with suspected ruptured abdominal aortic aneurysm. DESIGN: Randomised controlled trial. SETTING: 30 vascular centres (29 UK, 1 Canadian), 2009-13. PARTICIPANTS: 613 eligible patients (480 men) with a clinical diagnosis of ruptured aneurysm. INTERVENTIONS: 316 patients were randomised to the endovascular strategy (275 confirmed ruptures, 174 anatomically suitable for endovascular repair) and 297 to open repair (261 confirmed ruptures). MAIN OUTCOME MEASURES: 30 day mortality, with 24 hour and in-hospital mortality, costs, and time and place of discharge as secondary outcomes. RESULTS: 30 day mortality was 35.4% (112/316) in the endovascular strategy group and 37.4% (111/297) in the open repair group: odds ratio 0.92 (95% confidence interval 0.66 to 1.28; P=0.62); odds ratio after adjustment for age, sex, and Hardman index 0.94 (0.67 to 1.33). Women may benefit more than men (interaction test P=0.02) from the endovascular strategy: odds ratio 0.44 (0.22 to 0.91) versus 1.18 (0.80 to 1.75). 30 day mortality for patients with confirmed rupture was 36.4% (100/275) in the endovascular strategy group and 40.6% (106/261) in the open repair group (P=0.31). More patients in the endovascular strategy than in the open repair group were discharged directly to home (189/201 (94%) v 141/183 (77%); P<0.001). Average 30 day costs were similar between the randomised groups, with an incremental cost saving for the endovascular strategy versus open repair of £1186 (€1420; $1939) (95% confidence interval -£625 to £2997). CONCLUSIONS: A strategy of endovascular repair was not associated with significant reduction in either 30 day mortality or cost. Longer term cost effectiveness evaluations are needed to assess the full effects of the endovascular strategy in both men and women. TRIAL REGISTRATION: Current Controlled Trials ISRCTN48334791.

Screening, diagnosis and advances in aortic aneurysm surgery.

BACKGROUND: Aortic aneurysms are common in the elderly and a frequent cause of sudden death. As elective aneurysm repair has a mortality drastically lower than that associated with rupture, the emphasis must be on early detection and repair free from complications. Recent advances include ultrasound screening for asymptomatic abdominal aortic aneurysm (AAA) and clinical trials on the size of AAA that require repair. Pre-operative assessment, management of cardiac risk, autologous blood transfusion strategies, and endovascular stent graft technology to avoid major open surgery are all issues to be addressed. METHODS: Following a computerized Medline search for publications on the detection and treatment of abdominal and thoracic aortic aneurysm, the publications identified were then read and the references within those publications examined for further publications on this topic. We have reviewed these publications without attempting a meta-analysis. RESULTS: Randomized population studies have addressed ultrasound screening for AAA. Attendance for screening was good and AAA detection inexpensive. Screening men from 65 years reduces the mortality from rupture and is cost-effective. Open thoracic and abdominal aneurysm repair has a mortality of around 8%, with myocardial infarction being a frequent cause of death. Pre-operative reduction of cardiac risk by cardiac investigations and beta-blockade may reduce this mortality. Autologous transfusion techniques such as acute normovolaemic haemodilution and interoperative cell salvage reduce the need for allogeneic blood and the complications associated with open surgery. Minimally invasive endovascular repair is now possible for 40% of the AAA and an increasing proportion of thoracic aneurysms. CONCLUSIONS: The combination of screening, reduced pre-operative risk, and new minimally invasive techniques extends aortic aneurysm treatment into an increasingly elderly population. The combination of these techniques will reduce mortality from ruptured aortic aneurysm in the elderly and also reduce the stress associated with aneurysm surgery.