Endograft Sizing for Endovascular Aortic Repair and Incidence of Endoleak Type 1A

Detection of Endoleaks Following Thoracic and Abdominal Aortic Endovascular Aortic Repair-: A Comparison of Standard and Dynamic 4D-Computed Tomography Angiography

PURPOSE

Endoleaks are a common complication after endovascular aortic repair (EVAR) and thoracic endovascular aortic repair (TEVAR). The detection and correct classification of endoleaks is essential for the further treatment of affected patients. However, standard computed tomography angiography (CTA) provides no hemodynamic information on endoleaks, which can result in misclassification in complex cases. The aim of this study was to compare standard CTA (sCTA) with dynamic, dual-energy CTA (dCTA) for detection and classification of endoleaks following EVAR or TEVAR.

MATERIALS AND METHODS

This retrospective evaluation compared 69 sCTA diagnostic examinations performed on 50 different patients with 89 dCTA diagnostic examinations performed on 69 different patients.

RESULTS

In total, 15.9% of sCTA examinations and 49.4% of dCTA examinations led to the detection of endoleaks. With sCTA, 20.0% of patients were diagnosed with endoleaks, while with dCTA, 37.7% of patients were diagnosed with endoleaks. With sCTA, mainly Type 1 endoleaks were detected, whereas, with dCTA, the types of detected endoleaks were more evenly distributed. In comparison with the literature, the frequencies of endoleak types detected with dCTA better reflect the natural distribution than the frequencies detected with standard CTA.

CONCLUSION

Based on the retrospective comparative evaluation, dCTA could pose a valuable supplementary diagnostic tool resulting in a more accurate and realistic detection and classification of suspected endoleaks.

Spinal cord ischemia following simultaneous EVAR and TEVAR for concomitant thoracic and abdominal aortic aneurysms

OBJECTIVES

In patients with abdominal aortic aneurysms, 10-20% have concomitant thoracic aortic pathologies. These are typically managed with staged endovascular aneurysm repair (EVAR) and thoracic endovascular aortic repair (TEVAR) due to a perceived higher risk of spinal cord ischemia from a simultaneous intervention. We aimed to determine the outcomes of patients undergoing simultaneous EVAR and TEVAR for concomitant aneurysms.

METHODS

A retrospective cohort study was performed using the Vascular Quality Initiative registry from December 2003 to January 2021. Patients undergoing same-day EVAR and TEVAR were included and analyzed in accordance with the Society for Vascular Surgery reporting standards. Primary outcomes were technical success and spinal cord ischemia.

RESULTS

Simultaneous EVAR and TEVAR was performed in 25 patients. Median age was 75.0 (IQR 63.0-79.0) years and 20 (80.0%) patients were male. Two (4.0%) patients were symptomatic and four (16.0%) presented with rupture. Median maximum infrarenal and thoracic aortic diameter was 57.0 (IQR 52.0-65.0). Infrarenal aortic neck length was 15.0mm (IQR 10.0-25.0), and diameter was 27.0mm (IQR 24.5-30.0). Median procedure time was 185.0 minutes (IQR, 117.8-251.3), fluoroscopy time 32.7 minutes (IQR, 21.8-63.1), and contrast volume 165 ml (IQR 115.0-207.0). There were three (12.0%) Type Ia endoleaks and three (12.0%) Type II endoleaks in EVAR's, with one (4.0%) Type Ia and one (4.0%) Type II endoleak in TEVARs. In-hospital mortality occurred in three (12.0%) patients (one elective, two ruptures). Spinal cord ischemia occurred in one (4.0%) patient. This patient had a symptomatic aneurysm. Thoracic coverage extended from Zone 4 to Zone 5 and an emergent spinal drain was placed postoperatively. Symptoms were present on discharge. There was one (4.0%) conversion to open repair which occurred in a ruptured aneurysm. Technical success was achieved in 19 (76.0%) patients, however when excluding ruptured aneurysms, was achieved in 17 (81.0%) patients. Follow-up data was available for 19 (76.0%) patients at a median of 426.0 (IQR 329.0-592.5) days postoperatively. A total of 3 (12.0%) patients died during the late mortality period, at a mean of 509.0 (±503.7) days. Median change in abdominal and thoracic aortic sac diameter was -1.35mm (IQR -11.5-2.5) and 8.0 (IQR -10.5-12.0) respectively.

CONCLUSIONS

Simultaneous EVAR and TEVAR for concomitant abdominal and thoracic aortic aneurysms can be performed with low rates of spinal cord ischemia. Short- and mid-term outcomes are acceptable.

[Endoleaks in endovacular treatment of infrareneral abdominal aortic aneurysm (part I)]

We analyzed the PubMed, Scopus databases and the eLIBRARY electronic library regarding appropriate literature data. In the first part, modern classifications of endoleaks type 1 and 2 after stenting of infrarenal aortic aneurysm are considered. We described causes, risk factors and effectiveness of various treatment options.

Computational analysis of endovascular aortic repair proximal seal zone preservation with endoanchors: A case study in cylindrical neck anatomy

Background

Endovascular aortic repair is the common approach for abdominal aortic aneurysms, but endoleaks remain a significant problem with long-term success. Endoanchors have been found to reduce the incidence of type 1A endoleaks and can treat intraoperative type 1a endoleaks. However, little is known about the optimal number and position of endoanchors to achieve the best outcome.

Methods

Using image segmentation and a computational model derived from a reconstructed native patient abdominal aortic aneurysm geometry, the stability of the proximal seal zone was examined through finite element analysis in Abaqus (Dassault Systèmes, Providence, RI). The biomechanical parameter of contact area was compared for varying numbers (0, 2, 4, 8) and positions (proximal, medial, distal) of endoanchors under different adhesion strengths and physiologic pressure conditions.

Results

In every simulation, an increase in adhesion strength is associated with maintenance of proximal seal. For biologically plausible adhesion strengths, under conditions of normal blood pressure (120 mm Hg), the addition of any number of endoanchors increases the stability of the endograft-wall interface at the proximal seal zone by approximately 10% compared with no endoanchors. At hypertensive pressures (200 mm Hg), endoanchors increase the stability of the interface by 20% to 60% compared with no endoanchors. The positioning of endoanchors within the proximal seal zone has a greater effect at hypertensive pressures, with proximal positioning increasing stability by 15% compared with medial and distal positioning and 30% compared with no endoanchors.

Conclusions

Endoanchors improve fixation within the proximal seal zone particularly under conditions of high peak systolic pressure. Seal zone stabilization provides a mechanism through which endoanchor addition may translate into lower rates of type 1a endoleaks for patients.

Endovascular aortic repairs are commonly used to treat abdominal aortic aneurysms. Type 1a endoleaks threaten the long-term durability of repairs. Endoanchors have been found to reduce the incidence of this complication. Herein, we examine parameters surrounding optimal endoanchor number and positioning to reduce endovascular aortic repair failure. The computational modeling allowed for testing of endoanchors in varied adhesion strength between the endograft and the aorta, as well as hemodynamic conditions to mimic normotension vs hypertension. The results of the finite element analysis suggest that the addition of any number of endoanchors in the proximal seal zone is beneficial, especially with hypertensive loading.

Factors affecting the occurrence of proximal endoleak after endovascular abdominal aortic repair for abdominal aneurysms

Objective

This retrospective study was performed to assess the clinical and radiological variables associated with proximal type IA endoleak (EL) in patients treated with elective endovascular repair for abdominal aortic aneurysms.

Methods

The chi-square test, t-test, and logistic regression analysis were performed as appropriate. A P value of <0.05 was considered statistically significant.

Results

The data of 79 patients were analyzed. No mortality occurred. During follow-up (median, 28.5 months; interquartile range, 12.8–43.0 months), 10 patients developed type IA EL. In the logistic regression analysis, undersizing of the endograft diameter by <10% significantly affected the occurrence of type IA EL. When the diameter was used for measurements, less oversizing was significantly associated with a higher risk of type IA EL. When the area was used for measurements, oversizing of >20% significantly affected the occurrence of type IA EL.

Conclusion

When sizing endografts, a discrepancy was noted between the measurements of the diameter and area of the proximal neck. The area might represent a more accurate measurement than the axial diameter to optimize the proximal sealing and lower the risk of developing type IA EL.

Prosthetic Graft Dilation at the Aortic Arch in the Era of Hybrid Aortic Surgery

Objective: This study aims to evaluate the chronological size changes of the prosthetic graft in the aortic arch, which is used as a landing zone for a subsequent stent grafting in hybrid aortic surgery.

Materials and Methods: Eighty-five patients who underwent total aortic arch replacement followed by computed tomography follow-up for at least 30 months after the surgery were included in the study.

Results: Prosthetic grafts used were Hemashield (Maquet, Rastatt, Germany), J-Graft (Japan Lifeline Inc., Tokyo, Japan) and Triplex (Terumo, Tokyo, Japan). There was an initial increase in diameter compared to package size after implantation (Hemashield, 1.04±0.035 vs. J-Graft, 1.06±0.027 vs. Triplex, 1.04±0.023, p=0.13). Significant difference in graft dilation ratio was observed in Triplex (1.18±0.062) at long-term compared to Hemashield (1.07±0.052, p<0.001) and J-Graft (1.10±0.071, p<0.001). Multivariate analysis showed that age (r=0.002; 95% confidence interval [CI], 0.0001–0.0037; p=0.035), knitted-type prosthesis (r=0.089; 95% CI, 0.0610–0.1163; p<0.0001), and prevalence of cerebral vascular disease (r=0.038; 95% CI, 0.0030–0.0732; p=0.034) were independently associated with graft dilation after surgery.

Conclusion: Prosthetic graft selection and appropriate sizing of the stent graft should be considered for each individual undergoing hybrid aortic surgery to maintain sufficient oversizing of the stent graft.

Treatment of type 1A endoleak using coil embolization: a case report

In a type 1A endoleak, the endograft is unable to fully seal the proximal aneurysm neck and blood flow leaks between the wall of the aortic neck and the graft material. This article reports a case in which coil embolization was used and presents a literature review (PubMed, LILACS, and SciELO). Searches were run for articles published in the past 5 years using the descriptors “endoleak 1A”, “coil embolization,” and “treatment”. Type 1A endoleak occurs in 1.1% of patients within 30 days of graft placement. Treatment of an endoleak is obligatory and usually consists of sealing the proximal graft neck using stents and balloons to expand the landing zone or to increase the radial force of the graft. Some studies have suggested using embolization techniques with cyanoacrylate, fibrin glue, and Onyx, demonstrating success rates that exceed 97%. However, correction of type 1A endoleak using coil embolization has seldom been described.

Efficacy of ascending aortic banding technique concomitant with type I hybrid aortic arch repair in high-risk patients

Banding of the ascending aorta has been introduced as a less complex procedure to optimize the proximal landing zone of the stent graft in hybrid aortic arch surgery. However, data about the long-term results and effects of this technique are still limited. We aimed to study the efficacy of banding of the ascending aorta in hybrid aortic arch repair. The study included 11 high-risk patients with dilated ascending aorta (wider than 38 mm in diameter) undergoing ascending aortic banding for hybrid arch repair. Clinical outcomes, including technical success, endoleaks, perioperative mortality and morbidity, and sequential remodeling of the ascending aorta were investigated. The average diameter of the ascending aorta had been reduced (p = 0.02) from 42.1 mm (range = 39.0-46.4) to 37.2 mm (range = 35.6-38.6) after banding procedure. The technical success rate was 100.0%. No type I endoleak occurred, but 2 cases of distal stent graft-induced new entry required re-interventions. The 5-year survival and freedom from aortic events rates both were 81.8%. The ascending aortic diameter remained stable and no proximal migration of the stent graft was observed during the study period. The 5-year results validated the durability of this therapeutic modality, especially in high-risk patients.