Endovascular aneurysm repair: current status

Malnutrition provides important long-term prognostic information in patients undergoing endovascular abdominal aortic aneurysm repair

OBJECTIVES

Malnutrition has been shown to be associated with survival in a variety of diseases. Our aim is to evaluate the prognostic value of objective nutritional indexes indicating malnutrition, in patients underwent endovascular aortic replacement.

METHODS

We retrospectively evaluated 149 consecutive patients who underwent technically successful endovascular aortic replacement operation between October 2010 and August 2019. Objective nutritional indexes, prognostic nutritional index, geriatric nutritional risk index and controlling nutritional status, scores were calculated using the preoperative data. Optimal cut-off values were obtained by receiver operating characteristic analysis. According to the cut-off values, we investigated the relationship between indexes and the long-term all-cause mortality.

RESULTS

During mean 48.0 ± 30.3 months follow-up duration, in 47 of patients (31.5%), all-cause mortality were documented. In mortality group, prognostic nutritional index (42.8 ± 7.1 vs 51.3 ± 5.2, p < 0.001) and geriatric nutritional risk index (100.7 ± 10.1 vs 107.6 ± 9.2, p < 0.001) were significantly lower, controlling nutritional status score (2.0 (1.0-4.0) vs 1.0 (0.0-2.0), p < 0.001) was higher when compared to survivor group. Kaplan-Meier curves presented higher mortality incidence in malnutrition patients evaluated with objective nutritional indexes (Log-rang test, for all three indexes p < 0.001). Besides Cox-proportional hazard analysis showed all three nutritional indexes may be a predictive marker for all-cause mortality, prognostic nutritional index introduced more valuable data than other two indexes.

CONCLUSIONS

Malnutrition is associated with significant increase in postoperative long-term mortality in endovascular aortic replacement patients. Preoperatively calculated objective nutritional indexes especially prognostic nutritional index can be used as an important prognostic tool.

Haemodynamics in Different Flow Lumen Configurations of Customised Aortic Repair for Infrarenal Aortic Aneurysms

OBJECTIVE

Customised aortic repair (CAR) is a new and minimally invasive technique for the endovascular treatment of abdominal aortic aneurysms (AAAs). The aneurysm is completely sealed with a non-contained, non-cross linked polymer, while a new flow lumen is created with balloons. For CAR, the haemodynamically most favourable balloon and flow lumen configuration has not been established before; therefore, four flow parameters were assessed in an in vitro model.

METHODS

Three in vitro balloon configurations were implanted in an in vitro AAA model; a configuration with crossing balloons (CC) and two parallel configurations (PC1 and PC2). These three models were consecutively placed in a flow system that mimics physiological flow conditions. Laser particle imaging velocimetry (PIV) was used to resolve spatial and temporal flow patterns during the cardiac cycle. In house built algorithms were used to analyse the PIV data for the computing of (i) flow velocity; (ii) vorticity; (iii) wall shear stress (WSS); and (iv) time averaged wall shear stress (TAWSS).

RESULTS

Suprarenal flow patterns were similar in all models. The CC showed a higher infrarenal velocity than PC1 and PC2 (38 cm/s vs. 23 cm/s vs. 23 cm/s), and a higher vorticity at the crossing of the lumens (CC: 337/s; PC1 127/s; PC2: 112/s). The lowest vorticity was observed in PC2, especially in the infrarenal neck (CC: 200/s; PC1 164/s; PC2: 98/s). Although WSS and TAWSS varied between configurations, values were in the within non-pathological range.

CONCLUSION

The flow lumens created by three balloon configurations used in an in vitro model of CAR have been studied, and resulted in different haemodynamics. The differences in velocity and lower vorticity, especially at the crossing section of the two balloons, showed that PC2 has favourable haemodynamics compared with the CC and PC1. Future research will be focused on the clinical applicability of CAR based on the PC2 design.

[Proximal fixation devices in endovascular repair of abdominal aortic aneyrysm with unfavourable proximal neck anatomy]

Abdominal aortic aneurysm is a common vascular disease requiring surgical treatment. Currently, endovascular aortic repair is a good alternative to open surgery. However, high incidence of unfavorable anatomical variants of the proximal landing zone limit the use of endovascular aortic repair in these patients. Additional techniques can increase applicability of endovascular procedure with optimal results. Two patients with unfavorable proximal neck anatomy undergoing endovascular aortic repair with anchor type of proximal fixation devices are reported in the article.

Mechanical and geometrical determinants of wall stress in abdominal aortic aneurysms: A computational study

An aortic aneurysm (AA) is a focal dilatation of the aortic wall. Occurrence of AA rupture is an all too common event that is associated with high levels of patient morbidity and mortality. The decision to surgically intervene prior to AA rupture is made with recognition of significant procedural risks, and is primarily based on the maximal diameter and/or growth rate of the AA. Despite established thresholds for intervention, rupture occurs in a notable subset of patients exhibiting sub-critical maximal diameters and/or growth rates. Therefore, a pressing need remains to identify better predictors of rupture risk and ultimately integrate their measurement into clinical decision making. In this study, we use a series of finite element-based computational models that represent a range of plausible AA scenarios, and evaluate the relative sensitivity of wall stress to geometrical and mechanical properties of the aneurysmal tissue. Taken together, our findings encourage an expansion of geometrical parameters considered for rupture risk assessment, and provide perspective on the degree to which tissue mechanical properties may modulate peak stress values within aneurysmal tissue.

The Impact of Aneurysm Morphology and Anatomic Characteristics on Long-Term Survival after Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Hostile anatomic characteristics in patients undergoing endovascular abdominal aortic aneurysm repair (EVAR) and the placement of endografts not in concordance with the specific device anatomic guidelines (or instructions for use [IFU]) have shown decreased technical success of the procedure. But these factors have never been evaluated in regard to patient postoperative survival. We sought to assess the association between survival and (1) aneurysm anatomy and characteristics and (2) implantation in compliance with manufacturer's anatomic IFU guidelines in patients undergoing endovascular aortic aneurysm repair.

METHODS

The cohort included 273 consecutive patients who underwent EVAR at Baylor Heart and Vascular Hospital between January 1, 2002 and December 31, 2009 and had their preoperative computed tomography (CT) scan digitally retrievable. The CT scans and operative notes were then reviewed, and the anatomic severity grading (ASG) score, maximum aneurysm diameter, thrombus width, patency of aortic side branch vessels, and implantation in compliance with IFU guidelines were assessed. The unadjusted association between survival (assessed until November 1, 2011) and these variables was assessed with the Kaplan-Meier method. Moreover, propensity-adjusted (for a comprehensive array of clinical and nonclinical risk factors) proportional hazard models were developed to assess the adjusted associations.

RESULTS

Seven (2.56%) patients died within 30 days from EVAR, and 88 (30.04%) patients died during the study follow-up. Patient mean survival was 6.3 years. The unadjusted analysis showed a statistically significant association between survival and thrombus width (P = 0.007), ASG score (P = 0.004), and implantation in compliance with IFU guidelines (P = 0.007). However, the adjusted analysis revealed that none of the anatomic and compliance factors were significantly associated with long-term survival (ASG, P = 0.149; diameter, P = 0.836; thrombus, P = 0.639; patency, P = 0.219; and implantation compliance, P = 0.219).

CONCLUSIONS

Unfavorable aneurysm morphologic characteristics and endograft implantation not in compliance with IFU guidelines did not adversely affect patient survival after EVAR in this group of patients. This implies that unfavorable anatomy, even that which would necessitate implantation of the EVAR device outside of the IFU guidelines, should not necessarily contraindicate EVAR.

Surveillance Imaging Following Endovascular Aneurysm Repair

There is a significant risk of complication following endovascular abdominal repair (EVAR), including endoleak, graft translocation, thrombosis, and infection. Surveillance imaging is important for detecting EVAR complication. Surveillance modalities include conventional X-ray, computed tomography, magnetic resonance imaging, ultrasound, and conventional angiography, with inherent advantages and drawbacks to each modality. The authors present common complications following EVAR, and recent advances in the key modalities for surveillance.