A Novel Method to Estimate Iliac Tortuosity in Evaluating EVAR Access

Outcome of different endovascular modalities to treat common iliac artery aneurysms, single center study

INTRODUCTION

Iliac aneurysms occur in 10% of patients with abdominal aortic aneurysms (AAA). There are three different endovascular approaches to their treatment in the context of infrarenal Endovascular Aortic Aneurysm Repair (EVAR): occlusion by coiling the internal iliac, incorporation using an iliac branch device, and delaying repair using a bell bottom limb. We sought to determine outcomes associated with these three strategies in our practice.

METHODOLOGY

The study was a combined prospective cohort study with a retrospective arm: prospective patient recruitment was done for 1 year from September 2019 and ended by September 2020, and retrospective data was collected from 2017 to 2019. Demographic, procedural, and imaging data was collected. SPSS was used to analyze data as patients were classified by limbs in four groups: iliac branched, bell bottom, coil and cover technique, and standard treated limbs.

RESULTS

There were 65 male and 4 female patients included in this study incorporating 137 limbs with a mean age of 78 years (SD ± 8 years). Two patients died after discharge (at 3 and 21 months postoperatively, without hospital admission) and five patients were lost to long-term follow-up. Three patients had operations that deviated from the plan: one was an IBD converted to bell bottom, one was an IBD that was converted to coil and cover, and one was a bell bottom that did not seal. Follow-up revealed late type IB endoleak in three bell bottom limbs and one limb treated with coil and cover. Common iliac occlusion occurred in one IBD, three bell bottom limbs, and two limbs treated with coil/cover technique. There were four additional ischemic events (buttock claudication in three and intestinal ischemia in one): all ischemic events occurred in the coil and cover group (p = .001).

CONCLUSIONS

Given the small population size examined in this study, there is no statistical difference between treatment groups; however, there was a trend toward bell bottom technique being associated with higher incidence of type IB endoleak. Coil and cover technique was associated with decreased IB endoleak; however, Buttock claudication and intestinal ischemia occurred more significantly in this group. Using IBD may be the best strategy to improve short- and long-term outcomes in patients with iliac aneurysms.

Iliac Branch Devices in the Repair of Ruptured Aorto-iliac Aneurysms: A Multicenter Study

PURPOSE

To evaluate the outcomes of preserving the internal iliac artery (IIA) with iliac branched devices (IBDs) during acute endovascular repair of ruptured aortoiliac aneurysms.

MATERIAL AND METHODS

This is a multicenter retrospective review of all consecutive patients undergoing acute endovascular repair of ruptured aortoiliac aneurysm with an IBD at 8 aortic centers between December 2012 and June 2020. A control group was used where the IIA was intentionally occluded from the same study period. The main outcome measures were 30-day mortality, major adverse events, technical success, and clinical success. Secondary outcomes were buttock claudication, primary patency, primary-assisted and secondary patency of the IBD, occurrence of endoleak types I/III, and reintervention. Values are presented as numbers and percentages or interquartile range in parenthesis.

RESULTS

Forty-eight patients were included in the study: 24 with IBD and 24 with IIA occlusion. There was no difference in demographics, cardiovascular risk factors, and aneurysm extent. Twenty (83%) of them were hemodynamically stable during the procedure as opposed to 14 (58%, p=.23) with the IIA occlusion. Technical success was achieved in all cases with a procedure time of 180 (133-254) minutes, 45 (23-65) of which were from IBD. There were 2 (8%) deaths during the first 30 days and 2 (8%) major complications unrelated to the IBD, whereas in the IIA occlusion, the figures were 10 (42%) and 7 (29%), respectively. No patient in the IBD group developed buttock claudication compared to 8 (57%, p<.0001) in the IIA occlusion group; 1 (4%) patient developed bowel ischemia on both groups, with 1 in the IIA occlusion group needing resection. The median follow-up duration was 17 months (interquartile range 2-39) for the IBD group, with a primary patency of 60±14% at 3 years that went up to 92±8% with reinterventions (8 reinterventions in 6 patients). When the first 90 days were disregarded, there were no differences in survival between the groups.

CONCLUSION

IBD is a valid alternative for maintaining the pelvic circulation for endovascular aortic aneurysm repair of ruptured aortoiliac aneurysms. The technical success and midterm outcomes are very satisfactory but require patient selection particularly regarding hemodynamic stability. The reintervention rate is considerable, mandating continuous follow-up.

CLINICAL IMPACT

This multicenter study demonstrates that ruptured aortoiliac aneurysms do not necessarily require mandatory occlusion of hypogastric arteries. Iliac branch devices are shown to be a valid alternative in highly selected cases, with good midterm results, even if reinterventions are required in a significant proportion of patients.

Mixed reality for the assessment of aortoiliac anatomy in patients with abdominal aortic aneurysm prior to open and endovascular repair: Feasibility and interobserver agreement

OBJECTIVES

The objective is to evaluate the feasibility and interobserver agreement of a Mixed Reality Viewer (MRV) in the assessment of aortoiliac vascular anatomy of abdominal aortic aneurysm (AAA) patients.

METHODS

Fifty preoperative computed tomography angiographies (CTAs) of AAA patients were included. CTAs were assessed in a mixed reality (MR) environment with respect to aortoiliac anatomy according to a standardized protocol by two experienced observers (Mixed Reality Viewer, MRV, Brainlab AG, Germany). Additionally, all CTAs were independently assessed applying the same protocol by the same observers using a conventional DICOM viewer on a two-dimensional screen with multi-planar reconstructions (Conventional viewer, CV, GE Centricity PACS RA1000 Workstation, GE, United States). The protocol included four sets of items: calcification, dilatation, patency, and tortuosity as well as the number of lumbar and renal arteries. Interobserver agreement (IA, Cohen's Kappa, κ) was calculated for every item set.

RESULTS

All CTAs could successfully be displayed in the MRV (100%). The MRV demonstrated equal or better IA in the assessment of anterior and posterior calcification (κMRV: 0.68 and 0.61, κCV: 0.33 and 0.45, respectively) as well as tortuosity (κMRV: 0.60, κCV: 0.48) and dilatation (κMRV: 0.68, κCV: 0.67). The CV demonstrated better IA in the assessment of patency (κMRV: 0.74, κCV: 0.93). The CV also identified significantly more lumbar arteries (CV: 379, MRV: 239, p < 0.01).

CONCLUSIONS

The MRV is a feasible imaging viewing technology in clinical routine. Future efforts should aim at improving hologram quality and enabling accurate registration of the hologram with the physical patient.

Effects of Iliac Tortuosity Index on Fenestrated Endovascular Aortic Aneurysm Repair for Pararenal and Thoracoabdominal Aortic Aneurysms

PURPOSE

To evaluate the effect of iliac tortuosity on procedural metrics and outcomes of patients with complex aortic aneurysms (cAAs) undergoing repair with fenestrated/branched endografts (f/b-EVAR [endovascular aortic aneurysm repair]).

MATERIAL AND METHODS

The study is a single-center, retrospective review of a prospectively maintained database of patients undergoing aneurysm repair using f/b-EVAR between the years 2013 and 2020 at our institution. Included patients had at least 1 preoperative computed tomography angiography (CTA) available for analysis. Iliac artery tortuosity index (TI) was calculated using centerline of flow imaging from a 3-dimensional work station based on the formula: (centerline iliac artery length / straight-line iliac artery length). The associations between iliac artery tortuosity and procedural metrics, including total operative time, fluoroscopy time, radiation dose, contrast volume, and estimated blood loss (EBL), were evaluated.

RESULTS

During this period, 219 patients with cAAs underwent f/b-EVAR at our institution. Ninety-one patients (74% men; mean age = 75.2±7.7 years) met criteria for inclusion into the study. In this group, there were 72 (79%) juxtarenal or paravisceral aneurysms and 18 (20%) thoracoabdominal aortic aneurysms and 5 patients (5.4%) with failed previous EVAR. The average aneurysm diameter was 60.1±0.74 mm. Overall, 270 vessels were targeted, and 267 (99%) were successfully incorporated, including 25 celiac arteries, 67 superior mesenteric arteries, and 175 renal arteries. The mean total operative time was 236±83 minutes, fluoroscopy time was 87±39 minutes, contrast volume was 81±47 mL, radiation dose 3246±2207 mGy, and EBL was 290±409 mL. The average left and right TIs for all patients were 1.5±0.3 and 1.4±0.3, respectively. On multivariable analysis, the interval estimates suggest positive association between TI and procedural metrics to a certain degree.

CONCLUSIONS

In the current series, we found no definitive association between iliac artery TI and procedural metrics, including operative time, contrast used, EBL, fluoroscopy time, and dose in patients undergoing cAA repair using f/b-EVAR. However, there was a trend toward association between TI and all these metrics on multivariable analysis. This potential association needs to be evaluated in a larger series.

CLINICAL IMPACT

Iliac artery tortuosity should not exclude patients with complex aortic aneurysms from being offered fenestrated or branched stent graft repair. However, special considerations should be taken to mitigate the impact of access tortuosity on alignment of fenestrations with target vessels, including use of extra stiff wires, through and through access and delivering the fenestrated/branched device into another (larger) sheath such as a Gore DrySeal in patients with arteries large enough to accommodate such sheaths.

Iliac artery tortuosity index in Chinese patients with or without aortic artery aneurysms and related influencing factors

BACKGROUND

Iliac artery tortuosity is an important anatomical factor that influences the endovascular repair of aortic artery aneurysms (EVAR). The influencing factors of the iliac artery tortuosity index (TI) have not been well studied. TI of iliac arteries and related factors in Chinese patients with and without AAA were studied in this study.

SUBJECTS AND METHODS

One hundred and ten consecutive patients with AAA and 59 patients without AAA were included. For patients with AAA, the diameter of the AAA was 51.9 ± 13.3 mm (24.7-92.9 mm). Those without AAA had no history of definite arterial diseases and came from a cohort of patients diagnosed with urinary calculi. The central lines of the common iliac artery (CIA) and external iliac artery (EIA) were depicted. The actual length (L1) and the straight distance (L2) were measured and used to calculate the TI (L1/L2). Common demographic factors and anatomical parameters were analyzed to identify any related influencing factors.

RESULTS

For patients without AAA, the total TI of the left and right side was 1.16±0.14 and 1.16±0.13, respectively (p=0.48). For patients with AAAs, the total TI in the left and right side was 1.36±0.21 and 1.36±0.19, respectively (p=0.87). The TI in EIA was more severe than that in CIA both in patients with and without AAAs (p<0.01). Age was the only demographic factor found to be associated with TI in patients with AAA (Pearson's correlation coefficient r≈0.3, p<0.01) and without AAA (r≈0.6, p<0.01). For anatomical parameters, the diameter was positively associated with the total TI (left side: r=0.41, p<0.01; right side: r=0.34, p<0.01). The ipsilateral CIA diameter was also associated with the TI (left side: r=0.37, p<0.01; right side: r=0.31, p<0.01). The length of the iliac arteries was not associated with age or AAA diameter. Reduction of the vertical distance of the iliac arteries may be a common underlying reason for age and AAA.

CONCLUSIONS

Tortuosity of the iliac arteries was probably an age-related problem in normal individuals. It was also positively correlated with the diameter of the AAA and the ipsilateral CIA in patients with AAA. Attention should be paid to the evolution of iliac artery tortuosity and its influence when treating AAAs.

Limb graft occlusion after endovascular aneurysm repair with the Cook Zenith Alpha abdominal graft

OBJECTIVE

Prior reports of the low profile Zenith Alpha abdominal graft (Cook Medical Inc, Bloomington, IN) have shown impaired limb graft patency to be the primary causes of reintervention. Special notices from the manufacturer have indicated certain instructions for use (IFU) violations as the main reasons for these complications. In the present study, we assessed the incidence of limb graft occlusion (LGO) and analyzed the effects of the detailed anatomic risk factors for LGO highlighted in the IFU and previously reported studies.

METHODS

A retrospective study was performed of 241 patients treated with the low profile Zenith Alpha at a single institution from October 1, 2015 to September 30, 2018. All computed tomography angiograms were analyzed using three-dimensional software. Data were extracted from the electronic medical records until the end of the study period (December 31, 2020). The cumulative incidence of LGO and LGO-related reinterventions were assessed. A regression analysis was performed to evaluate the possible risk factors associated with the development of LGO at specified time points. These included aortic and iliac diameters, graft component oversizing, iliac tortuosity and calcification, overlap of graft components, proximal alignment of ipsilateral and contralateral legs, and sealing zone in the external iliac artery. Reader agreement of iliac calcification and tortuosity was assessed in patients with LGO.

RESULTS

A total of 33 limbs (7%) in 27 patients (11%) had become occluded. The cumulative incidence of LGO was 7% (95% confidence interval [CI], 5%-9%) per limb up to 3 years postoperatively. The previously described risk factors for LGO were studied using regression analysis; however, no positive association with LGO was identified. Heavily calcified common iliac arteries (CIAs) and external iliac arteries were protective against LGO compared with noncalcified vessels up to 3 years postoperatively (decreased risk, 17% [95% CI, -27% to -7%]; P = .001; and 15% [95% CI, -26 to -5]; P = .005, respectively). The reader agreement of iliac calcification and tortuosity showed substantial agreement (CIA intrareader kappa = 0.75; CIA interreader kappa = 0.62) and almost perfect agreement (intrareader kappa = 0.85; interreader kappa = 0.84), respectively.

CONCLUSIONS

The cumulative incidence of LGO after endovascular aneurysm repair with the Zenith Alpha graft was 7% per limb up to 3 years postoperatively. None of the analyzed risk factors suggested by the IFUs or current literature were positively associated with LGO.

[TAVR : Imaging for an optimal femoral approach]

Both computed tomography (CT) angiography and vascular ultrasound have a major role before and during a transfemoral approach to TAVR. CT angiography will determine whether the patient is eligible for a femoral approach. Peri-procedural arterial ultrasound will be helpful to improve safety and optimize results during the femoral approach. Being able to interpret both of these imaging modalities is of paramount importance for any interventional cardiologist who practices structural interventions.

Effect of iliac tortuosity on outcomes after iliac branch procedures

OBJECTIVE

To report a two-centers evaluation of the effects of iliac axis tortuosity on iliac branch device (IBD) results.

METHODS

From 2015 to 2021, all IBD procedures performed at two European centers were analyzed retrospectively. The preoperative pelvic tortuosity index (PTI), external tortuosity index (ETI), and double iliac sign (DIS) were assessed for each iliac axis submitted to IBD. The primary endpoints were technical success, early and mid-term IBD complications (occlusion, stenosis, endoleaks [ELs]) and reinterventions, and the association with the PTI, ETI, and DIS. The 30-day mortality, survival, freedom from complications and freedom from reinterventions (FFR) were the secondary endpoints.

RESULTS

During the study period, 224 patients had undergone 256 IBD procedures for 165 (64.5%) aortoiliac aneurysms, 44 (17.2%) isolated iliac aneurysms, 11 (4.3%) abdominal aortic aneurysms with a short iliac landing zone, and 36 (14.1%) type Ib ELs. IBD was planned with endovascular aortic aneurysm repair for 158 (61.7%), fenestrated/branched endovascular aortic aneurysm repair for 45 (7.6%), and isolated for 53 (20.7%) cases. Technical success and 30-day mortality were 99.2% (254 of 256) and 0.9% (2 of 224), respectively. A PTI >1.4, an ETI >1.7, and the DIS were tested to identify the risk factors for the endpoints. No ELs and 9 (3.5%) IBD occlusions, requiring five reinterventions (2%), had occurred within 30 days. No association with the PTI, ETI, or DIS was identified; IBD oversizing of ≥25% on the external iliac artery was independently related to occlusion (odds ratio, 4.3; 95% confidence interval [CI], 1-18.1; P = .045). The mean follow-up was 31 ± 27 months, with 11 IBD occlusions, 14 ELs, and 21 reinterventions. At 1, 3, and 5 years of follow-up survival, IBD patency, and FFR were 95%, 89%, and 80%; 93%, 91%, and 90%; and 93%, 89%, and 83%, respectively. The risk factors for overall complications (n = 34; 13.3%) and reinterventions (n = 26; 10.2%) were an ETI >1.7 (P = .037 and P = .019), a PTI >1.4 (P = .016 and P = .012), and a type Ib EL as the indication (P = .025 and P = .001), respectively. Cox regression confirmed PTI >1.4 as an independent predictor of overall complications and reinterventions (hazard ratio [HR], 2.3; 95% CI, 1.1-4.4; P = .018; and HR, 3 95% CI, 1.3-6.8; P = .018, respectively) and ETI >1.7 as an independent risk factor for ELs (HR 6; 95% CI, 2.1-17.5; P = .001). The freedom from complications and FFR were significantly lower with a PTI >1.4 at 3 years (73% vs 92% [log-rank P = .01] and 77% vs 93% [log-rank P = .001], respectively).

CONCLUSIONS

We found IBDs to be safe and effective in the treatment of aortoiliac aneurysms. Early complications are uncommon and related to endograft oversizing rather than anatomic characteristics in the present study. Iliac tortuosity is a risk factor for overall complications and reinterventions, in particular for IBD-related ELs.

Applicability of endovascular branched and fenestrated aortic arch repair devices to treat residual type A dissection after ascending replacement

OBJECTIVE

Endovascular repair of post-type-A aortic dissection after open ascending replacement (PTAD) has recently been shown as safe and feasible, but with limited anatomic applicability since only one stent graft was evaluated. We assessed anatomic and clinical applicability of six commercially available branched/fenestrated stent grafts for endovascular repair of PTAD.

METHODS

On postoperative CT-scans of 101 patients, we measured aortic diameter at: sino-tubular junction, supra-aortic vessels (SAV), and descending aorta, as well as the distances between these landmarks along the outer curvature of the arch and the diameters of the SAV. Anatomical applicability was evaluated according to the instructions-for-use, clinical applicability with regard to supra-aortic and iliac arteries. Assessed devices were: Cook aortic double branch; Terumo double branch; Najuta fenestrated; Endospan Nexus; Medtronic Mona LSA; and Gore TAG thoracic branch.

RESULTS

Single devices were anatomically and clinically applicable between 19/101 (Mona LSA) and 83/101 (Najuta) cases. Reasons for rejection varied considerably across devices. With all devices available, anatomical applicability was 97/101 and clinical applicability 95/101. Combinations of a fenestrated and a branched device showed the most favorable clinical applicability for a pair of two devices, ranging from 86/101 to 94/101.

CONCLUSIONS

Anatomical and clinical applicability of endovascular devices for the repair of PTAD is high for fenestrated and branched devices, and very high for the combination of fenestrated and branched devices. Manufacturers should amend specific device requirements for PTAD. Surgeons should emphasize the need for a sufficiently long and straight graft as a potential landing zone.

Iliofemoral tortuosity increases the risk of access site-related complications after aortic valve implantation and plug-based access site closure

Background

Access-site-related complications are often related to high-risk anatomy and technical pitfalls and impair the outcomes of transfemoral aortic valve implantations (TAVIs). Calcification and tortuosity are widely recognized risk factors, and their impact on procedural planning is left to the implanting experts’ discretion. To facilitate decision-making, we introduced a quantitative measure for iliofemoral tortuosity and assessed its predictive value for access-site-related vascular and bleeding complications.

Methods

We performed a single-centre prospective cohort study of consecutive, percutaneous transfemoral TAVI performed between April 2019 and March 2020. Medical history and all-cause mortality were extracted from the electronic patient files. Arterial anatomy and calcifications were evaluated using 3mensio Structural Heart software. The primary outcome was access-site-related vascular or bleeding complications.

Results

In this elderly, intermediate-risk population, we registered the primary outcome in 43 patients (39%), and major access-site complications in 10 patients (9.2%). Complete hemostasis was achieved in 77 patients (70.6%), by the application of the MANTA plug alone. In the group with access-site-related adverse events, compared with the group without, the tortuosity index was higher median (26% interquartile range [IQR 18%-33%] vs median 19% [IQR 13%-29%], respectively; P = 0.012), as was maximal angulation median (50° [IQR 40°-59°] vs median 43° [IQR 36°-51°], respectively; P = 0.026) were higher. Both variables had a significant effect on our primary outcome, with odds ratios (OR) of 3.1 (tortuosity, P = 0.005) and 2.6 (angulation, P = 0.020). The degree of angulation was a predictor of major complications too (odds ratio 7 [1.4-34.8]; P = 0.017).

Conclusions

Steeper angles and greater arterial elongation increase the risk of vascular and bleeding complications after femoral TAVI with the utilization of a plug-based closure device.

Experience With Unfavorable Iliac Access When Performing Fenestrated/Branched Endovascular Aneurysm Repair

PURPOSE

To review a single-center experience with fenestrated and branched endovascular aneurysm repair (f/bEVAR) in patients with challenging iliac anatomies.

MATERIALS AND METHODS

A retrospective review of the department's database identified 398 consecutive patients who underwent complex endovascular repair f/bEVAR between January 2010 and June 2018; of these, 67 had challenging accesses. The strategies implemented to overcome access issues were reviewed, using a dedicated scoring system to evaluate the access (integrating diameter, tortuosity, calcification, and previous open or endovascular repair).

RESULTS

In this subgroup of patients, the most common graft design was a 4-vessel fenestrated endograft (27, 40.3%). Hostile access was due to small diameter (<7 mm) in 25 patients (37.3%) and/or concentric calcifications in 19 patients (26.9%). Mean iliac diameter was 5.5±2.6 mm on the right side and 6.0±2.5 mm on the left side. Previous open or endovascular aortoiliac repair had been performed in 15 patients (22.4%), and 20 patients (29.9%) had a stent previously implanted in at least 1 iliac artery, resulting in the inability to perform standard fenestrated repair with access from both sides. Five patients (7.5%) had a single patent iliac access. Eight distinctive strategies were identified to overcome these access issues, including the use of preloaded renal catheters in the endograft delivery system, angioplasty, graft modification (branches instead of fenestrations or 4 preloaded fenestrations), a conduit via a retroperitoneal approach, iliac artery recanalization, and/or the multiple puncture technique. Technical success was achieved in 62 cases (92.5%). Four patients had access complications and 1 died in the early postoperative period of multiorgan failure. Median follow-up was 24.6 months (IQR 7.2, 41.3). Clinical success at the end of follow-up was achieved in 57 patients (85.1%). During follow-up, 14 patients died, including 4 from an aorta-related cause.

CONCLUSION

Dedicated strategies can be implemented to overcome hostile iliac access in patients with complex aneurysms when f/bEVAR is required. Typically, these maneuvers are associated with favorable outcomes.

The Use of Iliac Branched Devices in the Acute Endovascular Repair of Ruptured Aortoiliac Aneurysms

BACKGROUND

The objective of this study was to evaluate the feasibility and midterm outcomes of iliac branch devices (IBDs) to preserve the internal iliac artery perfusion in emergent endovascular repair of ruptured aorto-iliac aneurysms.

METHODS

Between December 2012 and July 2017, a total of 8 IBDs were implanted in 6 patients (the median age 65 years; all men) in a single tertiary referral center. The indication for IBD implantation was a ruptured abdominal aortic aneurysm with a concomitant common iliac artery aneurysm (n = 4) or isolated CIA aneurysms (n = 2). The main outcome measures were technical and clinical success. The secondary outcomes were primary and primary assisted patency, the occurrence of type I/III endoleaks, and reinterventions.

RESULTS

All patients were hemodynamically stable during the procedures, which were performed under local anesthesia. Technical success was achieved in all cases (the median total procedure time of 188 min and the median IBD procedure time of 28 min). The median follow-up was 34 months (interquartile range 19-78). There were no deaths during the follow-up and no major complications unrelated to the IBD. Two (25%) secondary interventions were performed for IBD occlusion in patients with bilateral IBDs. The other reintervention was a type II endoleak embolization in 1 of these 2 patients. The freedom from reintervention estimate was 75% through 2 years. The overall primary assisted patency was 100% through 3 years.

CONCLUSIONS

The use of IBDs in the acute setting is feasible to exclude ruptured aortoiliac aneurysms while maintaining pelvic circulation. The secondary intervention rate is considerable; however, the midterm assisted primary patency rates are promising. Further studies are needed to guide patient selection and to evaluate longer term outcomes.

A Methodology to Quantify the Geometrical Complexity of the Abdominal Aortic Aneurysm

The abdominal aortic aneurysm (AAA) anatomy influences the technical success of the endovascular aneurysm repair (EVAR), yet very few data regarding the aortic tree angles exist in the literature. This poses great limitations in the numerical analyses of endografts, constraining their design improvement as well as the identification of their operational limitations. In this study, a matrix Φ of 10 angles was constructed for the description of the pathological region and was implemented on a large dataset of anatomies. More specifically, computed tomography angiographies from 258 patients were analysed and 10 aortic angles were calculated per case, able to adequately describe the overall AAA shape. 9 dimensional variables (i.e. diameters and lengths) were also recorded. The median and extreme values of these variables were computed providing a detailed quantification of the geometrical landscape of the AAA. Moreover, statistical analysis showed that the identified angles presented no strong correlation with each other while no lateral or anterior/posterior symmetry of the AAA was identified. These findings suggest that endograft designers are free to construct any extreme case-studies with the values provided in a mix-and-match manner. This strategy can have a powerful effect in EVAR stent graft designing, as well as EVAR planning.

Anatomical Differences Between Intact and Ruptured Large Abdominal Aortic Aneurysms

Purpose: To compare different anatomical characteristics between intact and ruptured large abdominal aortic aneurysms (rAAA >80 mm) with the goal of refining the process of estimating rupture risk. Materials and Methods: A retrospective study involving 62 male patients with large (>80 mm) aneurysms matched for age and smoking produced a 31-patient elective group with a mean maximum aneurysm diameter of 92±9.7 mm and a 31-patient rAAA group (mean maximum aneurysm diameter 95.7±12 mm). Preoperative computed tomography angiography scans were analyzed with a dedicated workstation, and anatomical characteristics of the aortic neck, iliac arteries, and aneurysm were compared in multivariable regression analyses; the outcomes are given as the odds ratio (OR) with 95% confidence interval (CI). The prognostic utility of several characteristics as predictors of rupture occurrence was examined with receiver operating characteristic (ROC) curves. Results: Anatomical characteristics differing significantly between elective and ruptured aneurysms were the infrarenal aortic neck diameters at 5 mm, 10 mm and 15 mm; the neck length and calcification; the common iliac artery (CIA) lengths; the iliac artery indexes; the left CIA and external iliac artery diameters; and the total and true lumen aneurysm volumes. Intraluminal thrombus (ILT) volume did not differ (p=0.76), although its distribution in elective vs ruptured cases did [absent: 0% vs 19%, respectively (p=0.025); circumferential: 61% vs 35%, respectively (p=0.04)]. Total aneurysm volume was higher in rAAA (442±140 mL) vs intact AAA (331±143 mL, p=0.014), while the ILT/total aneurysm volume rate was lower in rAAA (55%) vs intact AAA (70%, p=0.02). Multivariate analysis determined that a shorter left CIA (OR 1.07, 95% CI 1.01 to 1.1, p=0.016) and a smaller total aneurysm volume (OR 1.007, CI. 1.001 to 1.014, p=0.016) were associated with intact AAA. After a ROC curve analysis, left CIA length <50 mm demonstrated a lower incidence of rupture (sensitivity 60% and specificity 78%), while total aneurysm volume <380 mL had 60% sensitivity and specificity. Conclusion: Large rAAAs seem to have different anatomical characteristics than similarly sized intact AAAs. Large intact AAAs have lower total aneurysm volumes and shorter left CIAs, with higher ILT/aneurysm volume rates.

Comparison of Qualitative and Quantitative Assessments of Iliac Artery Tortuosity and Calcification

Introduction:

During endovascular aneurysm repair, the iliac artery typically serves as a conduit for device delivery. The degree of tortuosity and calcification in the iliac artery ultimately determines whether the device can successfully traverse the vessel. These 2 parameters can be assessed using qualitative approaches or calculated using quantitative methods based on the Society for Vascular Surgery (SVS) reporting standards. The objective of this study was to determine whether qualitative methods are sufficient to accurately assess iliac artery tortuosity and calcification by calculating interobserver variability and comparing them to the SVS Reporting Standards.

Methods:

Three vascular surgeons reviewed preoperative computed tomography scans for 50 patients who underwent fenestrated endovascular aneurysm repair and qualitatively assessed left and right iliac artery tortuosity and calcification. Iliac artery geometries were segmented from these image sets. Tortuosity index and calcification length ratio were calculated and categorized based on the SVS Reporting Standards.

Results:

Interobserver variability was calculated for the qualitative assessments using interclass correlation coefficients. For tortuosity index, among the 3 observers, good agreement was found for the left iliac artery and fair agreement was found for the right. For calcification length ratio, excellent agreement was found for both iliac arteries. When compared to the quantitative assessment, the qualitative assessments underpredicted tortuosity in 2.3% of cases, matched the quantitative values in 16.7% of cases, and overpredicted tortuosity in 81.0% of cases. The qualitative assessments underpredicted calcification in 46.3% of cases, matched the quantitative values in 49.3% of cases, and overpredicted calcification in 4.3% of cases.

Conclusion:

Qualitative assessment of iliac artery tortuosity showed fair-to-good interobserver agreement and poor agreement to SVS Reporting Standards. Qualitative assessment of iliac artery calcification showed excellent interobserver agreement and fair agreement to SVS Reporting Standards. These trends should be considered when qualitative reporting methodologies are used.

Predictors of Prostatic Artery Embolization Technical Outcomes: Patient and Procedural Factors

PURPOSE

To identify technical factors that significantly change prostatic artery embolization (PAE) technical outcomes and to derive and test technical outcome predictive models.

MATERIALS AND METHODS

Retrospective analysis of PAEs performed by 2 operators (OPs) was performed: OP1, between April 2014 and May 2017 (n = 150); OP2, between February 2017 and December 2017 (n = 67). Multivariate analysis with mixed-effects modeling was used to test significance and derive predictive models. Mean difference was used to analyze prediction accuracy.

RESULTS

Moderate versus none subjective iliac tortuosity grade (SITG) and the presence of internal iliac atherosclerosis (PIIAA) versus none were associated with the following respective technical outcome increases: procedure time (PT): 43% (P < .01), 16% (P < .01); fluoroscopy time (FT): 47% (P < .01), 25% (P < .01); contrast volume (CV): 25.6 mL (P < .001), 13.7 mL (P = .01); and dose area product (DAP) 52% (P < .01), 20% (P = 0.03). Prostatic artery origin left obturator versus left superior vesical was associated with a 24% (P = .01) DAP decrease. For every 1 cc that prostate volume increased, CV decreased on average by 0.1 mL (P = .05). For every 1-cm decrease in patient height and 1-kg increase in weight, DAP increased on average by 0.02% (P < .01) for each. Unilateral versus bilateral versus 3-vessel embolization resulted in a 16.3-mL CV decrease on average for each additional vessel embolized (P = .03). The mean absolute differences between predicted and measured technical outcome values were: PT: 16 minutes, FT: 7 minutes, CV: 25 mL, and DAP: 44 Gy·cm².

CONCLUSIONS

In this study, higher SITGs and PIIAA most likely contributed to higher technical outcomes when controlling for the 2 OPs.

Analysis of Iliac Artery Geometric Properties in Fenestrated Aortic Stent Graft Rotation

Introduction:

A complication of fenestrated endovascular aneurysm repair is the potential for stent graft rotation during deployment causing fenestration misalignment and branch artery occlusion. The objective of this study is to demonstrate that this rotation is caused by a buildup of rotational energy as the device is delivered through the iliac arteries and to quantify iliac artery geometric properties associated with device rotation.

Methods:

A retrospective clinical study was undertaken in which iliac artery geometric properties were assessed from preoperative imaging for 42 cases divided into 2 groups: 27 in the nonrotation group and 15 in the rotation group. Preoperative computed tomography scans were segmented, and the iliac artery centerlines were determined. Iliac artery tortuosity, curvature, torsion, and diameter were calculated from the centerline and the segmented vessel geometry.

Results:

The total iliac artery net torsion was found to be higher in the rotation group compared to the nonrotation group (23.5 ± 14.7 vs 14.6 ± 12.8 mm−1; P = .05). No statistically significant differences were found for the mean values of tortuosity, curvature, torsion, or diameter between the 2 groups.

Conclusion:

Stent graft rotation occurred in 36% of the cases considered in this study. Cases with high iliac artery total net torsion were found to be more likely to have stent graft rotation upon deployment. This retrospective study provides a framework for prospectively studying the influence of iliac artery geometric properties on fenestrated stent graft rotation.

Initial clinical experience with the Zenith alpha stent-graft

PURPOSE

To assess safety and short-term efficacy of endovascular repair of the thoracic aorta with the new Zenith Alpha stent-graft.

METHODS

Between August 2010 and May 2014, 33 patients (21 men; mean age 73.2±9.0 years) were treated Zenith Alpha stent-graft (group ZA). Outcomes of this group were compared with those of 34 patients (25 men; mean age 70.3±8.5 years) treated contemporaneously with the Zenith TX-2 for the same pathologies (group TX). The primary outcome measure was technical success. Data on iliac tortuosity, minimum access vessel diameter, and previous unsuccessful treatment with other endografts was also recorded.

RESULTS

Technical success was 93.9% in group ZA and 91.2% in group TX (p=0.67). There was no case of surgical death or conversion to open repair in either group. Two (6%) type I endoleaks occurred in group ZA and 3 (9%) in group TX (p=0.67). Three patients died within 30 days in group ZA vs. none in group TX (p=0.07). Mean minimum access vessel diameter was significantly smaller (5.07 vs. 6.65 mm, p=0.002) and iliac tortuosity indices significantly higher in group ZA (1.34 vs. 1.25, p=0.02). Access vessel complications occurred in 1 (3%) patient in group ZA and 4 (12%) patients in group TX (p=0.17). Significantly more patients in group ZA (6, 18%) were unsuccessfully treated previously with other endografts vs. none in group TX (p=0.01).

CONCLUSION

The new Zenith Alpha appears to be equally as safe and efficacious as the Zenith TX-2 while being used in patients with demanding access vessel morphology.

Evaluation of the Zenith low-profile abdominal aortic aneurysm stent graft

BACKGROUND

Low-profile (LP) stent grafts are now commercially available in Europe for endovascular aortic aneurysm repair (EVAR). In this study the midterm outcomes and characteristics of patients treated with this last generation of stent grafts were compared with a cohort of patients treated with "standard-profile" (SP) stent grafts.

METHODS

The current study enrolled all patients treated for elective EVAR by the SP Zenith Flex stent graft (Cook Medical, Bloomington, Ind) between March 2010 and November 2011 and patients treated for elective EVAR by the Zenith LP stent graft (Cook Medical) between November 2011 and March 2013. All patients had a follow-up >18 months. Preoperative computed tomography angiograms were analyzed on a dedicated three-dimensional workstation. All data were prospectively collected in an electronic database and retrospectively analyzed. A comparative study was conducted.

RESULTS

The present study included 208 patients (107 SP and 101 LP). Patients' physiologic characteristics were similar in both groups. The iliac anatomy was considered "more challenging" in LP patients: respectively, 7% and 22% (P = .002) of SP and LP patients had bilateral external iliac diameter <7 mm; and 16% and 34% (P = .005) had a combination of an external iliac diameter <7 mm and an iliac tortuosity ratio index >1.5. No 30-day deaths were documented. The 24-month freedom from reintervention and overall survival rates after SP and LP were, respectively, 88% and 91% (P = .450) and 92% and 96% (P = .153). The 24-month rates for freedom from sac expansion and from limb occlusion were 96.4% and 98.7% (P = .320) and 92% and 95% (P = .293), respectively. One patient in each group presented with a type I endoleak during follow-up, and two LP patients presented with a type III endoleak (P = .235).

CONCLUSIONS

This study demonstrates that the last-generation LP stent grafts have favorable midterm outcomes similar to SP stent grafts despite being used to treat more patients with unfavorable iliac anatomy.

Studying the Interaction of Stent-Grafts and Treated Abdominal Aortic Aneurysms

Since the advent of endovascular repair of aortic aneurysms (EVAR), clinical focus has been on preventing loss of sealing at the level of the infrarenal neck, which leads to type I endoleak and repressurization of the aneurysm sac. Enhanced mechanisms for central fixation and seal have consequently lowered the incidence of migration and endoleaks. However, endograft limb thrombosis and its causal mechanisms have not been addressed adequately in the literature. This article reviews the pathophysiological mechanisms associated with limb thrombosis in order to facilitate better clinical judgment to prevent iliac adverse effects.

Secondary modification into aortouniiliac configuration to salvage failed endovascular aneurysm repair is safe and effective but not associated with higher intervention rates during long-term follow-up

BACKGROUND

Reports of secondary modifications into aortouniiliac configuration to salvage-failed endovascular aneurysm repair (EVAR) are limited. We evaluated long-term results after these procedures and compared them with those after primary aortouniiliac endografting (AUE).

METHODS

A retrospective review of all EVAR performed from March 1995 until July 2011 was conducted. Patients were included when primary AUE (group I) or modification into aortouniiliac configuration (group II) was done.

RESULTS

Data analysis obtained 27 group I and 23 group II patients. Salvage of failed EVAR could be achieved in 96% of group II patients, and mortality was zero. Frequency of adverse events and amount of interventions to maintain aneurysm exclusion were not increased after secondary AUE. Kaplan-Meier estimates for long-term survival between groups were comparable (P = .36).

CONCLUSIONS

Secondary AUE allows correction of graft-related endoleaks potentially leading to late aneurysm rupture. Complications and adverse events throughout long-term follow-up were not necessarily increased when compared with primary AUE.