Changes in Noninvasive Arterial Stiffness and Central Blood Pressure After Endovascular Abdominal Aneurysm Repair

Purpose:

To evaluate the impact of elective endovascular aneurysm repair (EVAR) on the carotid-femoral pulse wave velocity (cfPWV) and central pressure waveform, through 1-year follow-up.

Materials and Methods:

A tonometric device was used to measure cfPWV and estimate the central pressure waveform in 20 patients with an infrarenal abdominal aortic aneurysm scheduled for elective EVAR. The evaluated central hemodynamic parameters included the central pressures, the augmentation index (AIx), and the subendocardial viability ratio (SEVR). AIx quantifies the contribution of reflected wave to the central systolic pressure, whereas SEVR describes the myocardial perfusion relative to the cardiac workload. Measurements were performed before EVAR, at discharge, and 6 weeks and 1 year after EVAR.

Results:

CfPWV was increased at discharge (12.4±0.4 vs 11.3±0.5 m/s at baseline; p=0.005) and remained elevated over the course of 1-year follow-up (6 weeks: cfPWV = 12.2±0.5 m/s; 1 year: cfPWV = 12.2±0.7 m/s, p<0.05). After an initial drop in systolic central pressure at discharge, all the central pressures increased thereafter up to 1 year, without significant differences compared with baseline. The same was observed for the AIx and SEVR.

Conclusion:

Endovascular aortic aneurysm repair caused an increase in pulse wave velocity compared with baseline, which remained elevated through 1 year follow-up, which may be related to an increased cardiovascular risk. However, no differences in central pressure, augmentation index, and subendocardial viability ration were observed during follow-up.

The relation between physical fitness, frailty and all-cause mortality after elective endovascular abdominal aortic aneurysm repair

BACKGROUND

Accurate determination of probable surgical outcomes is fundamental in decision-making regarding appropriate abdominal aortic aneurysm treatment. These outcomes depend, among other factors, on patient-related factors such as physical fitness. The primary aim of this study was to evaluate the correlation between physical fitness, measured by the metabolic equivalent of task (MET) score and the five-factor Modified Frailty Index (MFI-5), and all-cause mortality.

METHODS

Four hundred twenty-nine patients undergoing elective endovascular treatment of an infrarenal aortic aneurysm (EVAR) from January 2011 to September 2018 were identified in an existing local abdominal aortic aneurysm database. Physical fitness was measured by the MFI-5 and the METs as registered during preoperative screening. The primary end point was 1-year all-cause mortality and secondary end points included 5-year all-cause mortality, freedom from aneurysm-related mortality and aneurysm-related reinterventions. Correlations were analyzed using Spearman's rho and survival was analyzed using Kaplan-Meier analyses. The effect of physical fitness on mortality was assessed by binary logistics regression analyses.

RESULTS

There was a positive correlation between the MFI-5 and 1-year all-cause mortality (Rho = 0.163; P = .001), but not between the METs and 1-year all-cause mortality (Rho = -0.083; P = .124). A significant correlation between both MFI-5 and METs and 5-year all-cause mortality was observed (Rho = 0.255; P < .001 and Rho = -0.154; P = .004). When stratified by the MFI-5, the 1- and 5-year follow-up survival rates were 95.1% and 85.9%, respectively, in the group with the lowest MFI-5 and 74.5% and 33.1% in the group with the highest MFI-5 score (P = .007 and P < .001). When stratified by METs categories for 1-year follow-up, no significant differences in survival between the groups were observed (P = .090). The 5-year follow-up survival rate was 39.4% in the lowest METs category and 76.3% in the highest METs category (P = .039). Logistic regression analysis, assessing the impact of age, sex, METs, and the MFI-5 on the risk of all-cause mortality, showed that only age and the MFI-5 made a significant contribution.

CONCLUSIONS

There is a significant positive association between the MFI-5 and both the 1- and 5-year all-cause mortality rates after EVAR; METs only correlated with the 5-year all-cause mortality. Only age and the MFI-5 contributed to predicting overall survival after EVAR; therefore, it could be recommended to add the MFI-5 for guidance in preoperative counselling.

Changes in Noninvasive Arterial Stiffness and Central Blood Pressure After Endovascular Abdominal Aneurysm Repair

PURPOSE

To evaluate the impact of elective endovascular aneurysm repair (EVAR) on the carotid-femoral pulse wave velocity (cfPWV) and central pressure waveform, through 1-year follow-up.

MATERIALS AND METHODS

A tonometric device was used to measure cfPWV and estimate the central pressure waveform in 20 patients with an infrarenal abdominal aortic aneurysm scheduled for elective EVAR. The evaluated central hemodynamic parameters included the central pressures, the augmentation index (AIx), and the subendocardial viability ratio (SEVR). AIx quantifies the contribution of reflected wave to the central systolic pressure, whereas SEVR describes the myocardial perfusion relative to the cardiac workload. Measurements were performed before EVAR, at discharge, and 6 weeks and 1 year after EVAR.

RESULTS

CfPWV was increased at discharge (12.4±0.4 vs 11.3±0.5 m/s at baseline; p=0.005) and remained elevated over the course of 1-year follow-up (6 weeks: cfPWV = 12.2±0.5 m/s; 1 year: cfPWV = 12.2±0.7 m/s, p<0.05). After an initial drop in systolic central pressure at discharge, all the central pressures increased thereafter up to 1 year, without significant differences compared with baseline. The same was observed for the AIx and SEVR.

CONCLUSION

Endovascular aortic aneurysm repair caused an increase in pulse wave velocity compared with baseline, which remained elevated through 1 year follow-up, which may be related to an increased cardiovascular risk. However, no differences in central pressure, augmentation index, and subendocardial viability ration were observed during follow-up.

Remodeling of Abdominal Aortic Angulation and Curvature After Endovascular Aneurysm Repair in Patients With vs Without Late Type Ia Endoleak or Endograft Migration

PURPOSE

To investigate aortic remodeling of the supra- and infrarenal aorta from preoperative to 1 month and midterm follow-up after endovascular aneurysm repair (EVAR) by analyzing changes in angulation and curvature in patients with vs without late type Ia endoleak or device migration.

MATERIALS AND METHODS

From a multicenter database, 35 patients (mean age 76±5 years; 31 men) were identified with late (>1 year) type Ia endoleak or endograft migration (≥10 mm) and defined as the complication group. The control group consisted of 53 patients (mean age 75±7 years; 48 men) with >1-year computed tomography angiography (CTA) follow-up and no evidence of endoleaks. Suprarenal and infrarenal angles were measured on centerline reconstructions of the preoperative, 1-month, and midterm CTA scans. The value and location relative to baseline of maximum suprarenal and infrarenal curvature were determined semiautomatically using dedicated software. Changes were determined at 1 month compared with the preoperative CTA and at midterm compared with 1 month.

RESULTS

Preoperative suprarenal angulation was significantly greater in the complication group compared to the controls (34°±18° vs 24°±17°, p=0.008). It decreased significantly at 1 month in the complication group (29°±16°, p=0.011) and at midterm follow-up in the controls (20°±19°, p<0.001). Preoperative infrarenal angulation was not significantly different (57°±15° vs 49°±24°, p=0.114). This measurement increased significantly through midterm follow-up in the complication group (63°±23°, p<0.001) but remained stable in the controls (46°±22°). Preoperative suprarenal curvature was not significantly different (38±22 m^-1 vs 29±25 m^-1, p=0.115). This variable increased significantly through midterm follow-up in the complication group (44±22 m^-1) but remained constant in the controls (28±22 m^-1). Preoperative infrarenal curvature was significantly greater in the complication group (77±29 m^-1 vs 65±28 m^-1, p=0.047) and decreased significantly in both groups during midterm follow-up (50±17 m^-1 vs 41±19 m^-1 p=0.033). The location of the maximum curvature with regard to baseline shifted significantly distally in the complication group (54±43 to 72±41 mm, p<0.001), while it remained stable in the controls (46±33 to 48±31 mm).

CONCLUSION

At midterm follow-up, significant differences in supra- and infrarenal angulation and curvature were observed between patients with vs without type Ia endoleak or migration. The location of the maximum curvature shifted distally in patients with complications. The aortic morphology is more stable during midterm follow-up in the patients without endoleaks.

Embolization of the false lumen using IMPEDE-FX embolization plugs as part of treatment of an infrarenal post-dissection aneurysm: a case report

Background

This case report demonstrates the value of IMPEDE-FX plugs in an embolization procedure of a false lumen of an infrarenal post-dissection aneurysm.

Case presentation

A 69-year-old patient was treated with mitral valve replacement, complicated by a Stanford type-A dissection. After 9 years he presented with an enlarging infrarenal post-dissection aneurysm. The false lumen was embolized using multiple IMPEDE-FX plugs as part of the treatment in addition to embolization of the inferior mesenteric artery and overstenting of the re-entry in the right iliac artery. At 15 months the CTA showed a fully thrombosed false lumen and remodeling of the true lumen.

Conclusions

The false lumen of an infrarenal post-dissection aneurysm can successfully be embolized using IMPEDE-FX embolization plugs as part of the treatment strategy. Prospective trials on patients with non-thrombosed false lumina are indicated.

Migration After Endovasclar Aneurysm Sealing in Conjunction With Chimney Grafts

Purpose

To assess the incidence of migration after endovascular aneurysm sealing (EVAS) in conjunction with chimney grafts (chEVAS) for repair of abdominal aortic aneurysms (AAAs).

Materials and Methods

A retrospective, observational cohort study was conducted of 31 patients (mean age 75.7 years; 27 men) treated for juxtarenal AAA between April 2013 and December 2018 at single centers in New Zealand and the Netherlands. The majority of patients received >1 chimney graft (13 single, 13 double, and 5 triple) during chEVAS. Six patients had only the first postoperative scan, so the migration analysis was based on 25 patients.

Results

Median seal length assessed on the first postoperative computed tomography scan was 36.5 mm. The assisted technical success rate was 93.5% with 2 technical failures. Median time to final imaging follow-up was 17 months in 25 patients. At the latest follow-up, there were no cases of caudal migration >10 mm. Freedom from caudal movement of 5 to 9 mm was estimated as 86.1% at 1 year and 73.9% at 2 years; freedom from clinically relevant migration (movement requiring reintervention) was 100% at both time intervals. However, at 3 years there were 2 cases of caudal movement of 5 to 9 mm and a type Ia endoleak warranting reintervention. No correlation between migration and aneurysm growth (p=0.851), endoleak (p=0.562), or the number of chimney grafts (p=0.728) was found. During follow-up, 2 patients (7%) had aneurysm rupture and 10 (33%) had reinterventions. Eight patients (27%) died; 2 were aneurysm-related (7%) and due to the consequences of a reintervention.

Conclusion

In the 2 years following chEVAS, there was no caudal migration >10 mm, but nearly a quarter of patients had caudal movement of 5 to 9 mm. A trend was observed toward ongoing migration that required intervention at 3-year follow-up. chEVAS is technically challenging and should be considered only for patients with no viable alternative treatment option.

A Late Post-EVAR Rupture in a 102-Year-Old Patient Related to a Type II Endoleak

PURPOSE

Endovascular abdominal aortic aneurysm repair (EVAR) is progressively being applied in the elderly population. Type II endoleaks are common and mostly benign, but they are related to more aneurysm sac expansion after EVAR. They may lead to rupture in <1% of cases. We present a case of a centenarian with a post-EVAR rupture, related to type II endoleak, and discuss the use of EVAR on the management of this type of endoleak in an extremely old patient.

CASE PRESENTATION

A 102-year-old man with a history of EVAR 12 years earlier, presented to the emergency department with a drop of consciousness. A computed tomography revealed a ruptured abdominal aortic aneurysm. Angiography showed a type II endoleak related to patent lumbar arteries deriving from collateral branches of the right internal iliac artery. Embolization was not successful and subsequently the ostium of the iliolumbar artery was overstented, obliterating the feeding branch. The postoperative course was complicated by a deterioration of chronic obstructive pulmonary disease and patient was discharged home on the seventh postprocedural day; nonetheless, he died on postoperative day sixteenth due to respiratory complications.

CONCLUSION

Complications following EVAR are a real threat and emphasize the need for follow-up. The current case report shows that age per se should not be a contraindication for EVAR nor for follow-up. Also, late ruptures due to type II endoleaks could be treated in the very elderly population although larger series are required for robust conclusions.

A novel roller pump for physiological flow

Having physiological correct flow waveforms is a key feature for experimental studies of blood flow, especially in the process of developing and testing a new medical device such as stent, mechanical heart valve, or any implantable medical device that involves circulation of blood through the device. It is also a critical part of a perfusion system for cardiopulmonary bypass and extracorporeal membrane oxygenation procedures. This study investigated the feasibility of a novel roller pump for use in experimental flow phantoms. Flow rates of carotid flow profile measured directly with the ultrasonic flow meter matched well with the reference flow rates programmed into the machine with similarity index of 0.97 and measured versus programmed flow rates at specific time‐points of peak systolic velocity (PSV): 0.894 vs 0.880, end systolic velocity (ESV): 0.333 vs 0.319, and peak diastolic velocity (PDV): 0.514 vs 0.520 L/min. Flow rates derived from video analysis of the pump motion for carotid, suprarenal, and infrarenal flows also matched well with references with similarity indices of 0.99, 0.99, and 0.96, respectively. Measured flow rates (mean/standard deviation) at PSV, ESV, and PDV time‐points for carotid: 0.883/0.016 vs 0.880, 0.342/0.007 vs 0.319, and 0.485/0.009 vs 0.520; suprarenal: 3.497/0.014 vs 3.500, 0.004/0.003 vs 0, and 1.656/0.073 vs 1.453; infrarenal: 4.179/0.024 vs 4.250, −1.147/0.015 vs −1.213, and 0.339/0.017 vs 0.391 L/min, respectively. The novel roller pump is suitable for benchtop testing of physiological flow.

Endograft Conformability in Fenestrated Endovascular Aneurysm Repair for Complex Abdominal Aortic Aneurysms

Purpose: To compare the impact of 2 commercially available custom-made fenestrated endografts on patient anatomy. Materials and Methods: The records of 234 patients who underwent fenestrated endovascular aneurysm repair for abdominal aortic aneurysm from March 2002 to July 2016 in 2 hospitals were screened to identify those who had pre- and postoperative computed tomography angiography assessments with a slice thickness of ≤2 mm. The search identified 145 patients for further analysis: 110 patients (mean age 72.4±7.1 years; 94 men) who had been treated with the Zenith Fenestrated (ZF) endograft and 35 patients (mean age 72.3±7.3 years; 30 men) treated with the Fenestrated Anaconda (FA) endograft. Measurements included aortic diameters at the level of the superior mesenteric artery (SMA) and renal arteries, target vessel angles, target vessel clock positions, and the target vessel tortuosity index. Variables were tested for inter- and intraobserver agreement. Results: There was a good agreement between observers in all tested variables. The native anatomy changed in both groups after endograft implantation. In the ZF group, changes were seen in the angles of the celiac artery (p=0.012), SMA (p=0.022), left renal artery (LRA) (p<0.001), and the right renal artery (RRA) (p<0.001); the aortic diameter at the SMA level (p<0.001); and the LRA (p<0.001) and RRA (p<0.001) clock positions. In the FA group, changes were seen in the angles of the LRA (p=0.001) and RRA (p<0.001) and in the SMA tortuosity index (p=0.044). Between group differences in changes were seen for the aortic diameters at the SMA and renal artery levels (p<0.001 for both) and the LRA clock position (p=0.019). Conclusion: Both custom-made fenestrated endografts altered vascular anatomy. The data suggest a higher conformability of the Fenestrated Anaconda endograft compared with the Zenith Fenestrated.

Physiological Appearance of Hybrid FDG-Positron Emission Tomography/Computed Tomography Imaging Following Uncomplicated Endovascular Aneurysm Sealing Using the Nellix Endoprosthesis

Purpose: To investigate the physiological uptake of hybrid fluorine-18-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) before and after an uncomplicated endovascular aneurysm sealing (EVAS) procedure as a possible tool to diagnose EVAS graft infection and differentiate from postimplantation syndrome. Materials and Methods: Eight consecutive male patients (median age 78 years) scheduled for elective EVAS were included in the prospective study (ClinicalTrials.gov identifier NCT02349100). FDG-PET/CT scans were performed in all patients before the procedure and 6 weeks after EVAS. The abdominal aorta was analyzed in 4 regions: suprarenal, infrarenal neck, aneurysm sac, and iliac. The following parameters were obtained for each region: standard uptake value (SUV), tissue to background ratio (TBR), and visual examination of FDG uptake to ascertain its distribution. Demographic data were obtained from medical files and scored based on reporting standards. Results: Visual examination showed no difference between pre- and postprocedure FDG uptake, which was homogenous. In the suprarenal region no significant pre- and postprocedure differences were observed for the SUV and TBR parameters. The infrarenal neck region showed a significant decrease in the SUV and no significant decrease in the TBR. The aneurysm sac and iliac regions both showed a significant decrease in SUV and TBR between the pre- and postprocedure scans. Conclusion: Physiological FDG uptake after EVAS was stable or decreased with regard to the preprocedure measurements. Future research is needed to assess the applicability and cutoff values of FDG-PET/CT scanning to detect endograft infection after EVAS.

A novel roller pump for physiological flow

Having physiological correct flow waveforms is a key feature for experimental studies of blood flow, especially in the process of developing and testing a new medical device such as stent, mechanical heart valve, or any implantable medical device that involves circulation of blood through the device. It is also a critical part of a perfusion system for cardiopulmonary bypass and extracorporeal membrane oxygenation procedures. This study investigated the feasibility of a novel roller pump for use in experimental flow phantoms. Flow rates of carotid flow profile measured directly with the ultrasonic flow meter matched well with the reference flow rates programmed into the machine with similarity index of 0.97 and measured versus programmed flow rates at specific time‐points of peak systolic velocity (PSV): 0.894 vs 0.880, end systolic velocity (ESV): 0.333 vs 0.319, and peak diastolic velocity (PDV): 0.514 vs 0.520 L/min. Flow rates derived from video analysis of the pump motion for carotid, suprarenal, and infrarenal flows also matched well with references with similarity indices of 0.99, 0.99, and 0.96, respectively. Measured flow rates (mean/standard deviation) at PSV, ESV, and PDV time‐points for carotid: 0.883/0.016 vs 0.880, 0.342/0.007 vs 0.319, and 0.485/0.009 vs 0.520; suprarenal: 3.497/0.014 vs 3.500, 0.004/0.003 vs 0, and 1.656/0.073 vs 1.453; infrarenal: 4.179/0.024 vs 4.250, −1.147/0.015 vs −1.213, and 0.339/0.017 vs 0.391 L/min, respectively. The novel roller pump is suitable for benchtop testing of physiological flow.

Two-year results of a multicenter randomized controlled trial comparing Mechanochemical endovenous Ablation to RADiOfrequeNcy Ablation in the treatment of primary great saphenous vein incompetence (MARADONA trial)

OBJECTIVE

Endothermal techniques have proved to be effective for treatment of incompetent truncal veins. The tumescentless mechanochemical ablation (MOCA) technique has become an alternative treatment modality, but its outcome with regard to endothermal techniques is still unclear.

METHODS

A multicenter prospective randomized controlled trial was designed comparing MOCA with radiofrequency ablation (RFA) to treat great saphenous vein incompetence with the hypothesis that MOCA is associated with less postprocedural pain and a comparable anatomic and clinical success rate at 1-year follow-up. Disease-specific quality of life and general health-related quality of life (HRQoL) were measured using questionnaires. Inclusion was terminated prematurely because reimbursement was suspended.

RESULTS

A total of 213 patients (46.3% of intended number of patients) were randomized, of whom 209 were treated (105 in the MOCA group and 104 in the RFA group). Overall median pain scores during the first 14 days were lower after MOCA (0.2 vs 0.5 after RFA; P = .010), although the absolute difference was small. At 30 days, similar complication numbers (MOCA, n = 62; RFA, n = 63) and HRQoL scores (Aberdeen Varicose Vein Questionnaire: MOCA, 8.9; RFA, 7.6; P = .233) were observed. Hyperpigmentation was reported in seven patients in the MOCA group and two patients in the RFA group (P = .038). In the MOCA group, there were four complete failures (3.8%) compared with none in the RFA group (P = .045), although in one patient at 1 year, the vein showed occlusion. Median 30-day Venous Clinical Severity Score (VCSS) was significantly lower at 30 days after MOCA (1.0 vs 2.0 in the RFA group; P = .001), whereas VCSS was comparable at baseline (MOCA, 4.0; RFA, 5.0; P = .155). The 1- and 2-year anatomic success rate was lower after MOCA (83.5% and 80.0%) compared with RFA (94.2% and 88.3%; P = .025 and .066), mainly driven by partial recanalizations. After 2 years of follow-up, no differences were observed in the number of complete failures. Similar clinical success rates at 1 year (MOCA, 88.7%; RFA, 93.2%; P = .315) and 2 years (MOCA, 93.0%; RFA, 90.4%; P = .699) and no differences in HRQoL scores on the Aberdeen Varicose Vein Questionnaire at 1 year (MOCA, 7.5; RFA, 7.0; P = .753) and 2 years (MOCA, 5.0%; RFA, 4.8%; P = .573) were observed. There were two cardiac serious adverse events, a ventricular fibrillation in the MOCA group (1 year) and an unstable angina in the RFA group (2 years). One deep venous thrombosis occurred in the RFA group on 1-year duplex ultrasound, without clinical sequelae.

CONCLUSIONS

Unilateral treatment with MOCA in the short term resulted in less postoperative pain but more hyperpigmentation compared with RFA and a faster improvement in VCSS. More anatomic failures were reported after MOCA, mostly driven by partial recanalizations, but both techniques were associated with similar clinical outcomes at 1 year and 2 years.

Outcomes after treatment of complex aortic abdominal aneurysms with the fenestrated Anaconda endograft

OBJECTIVE

To date, information on the fenestrated Anaconda endograft is limited to case series with a small sample size. This study was performed to assess the technical and clinical outcome of this device in a large international case series.

METHODS

All worldwide centers having treated more than 15 complex abdominal aortic aneurysms (AAA) or type IV thoracoabdominal aortic aneurysm patients with the fenestrated Anaconda endograft were approached. Main outcome parameters were procedural technical success, postoperative and follow-up clinical outcome for endoleaks, target vessel patency, reintervention rate, and patient survival.

RESULTS

Three hundred thirty-five consecutive cases treated between June 2010 and May 2018 in 11 sites were included. Patients were treated for a short neck infrarenal (n = 98), juxtarenal (n = 191), suprarenal AAA (n = 27), or type IV thoracoabdominal aortic aneurysm (n = 19). Mean age was 73.6 ± 4.6 years (292 male). Endografts contained a total of 920 fenestrations, with a mean of 2.7 ± 0.8 fenestrations per case. Technical success was 88.4% (primary, 82.7%; assisted primary 5.7%). In 6.9% of cases, a procedural type IA endoleak was observed, spontaneously disappearing in 82.6% during early follow-up. The development of a type IA endoleak was associated with greater neck angulation (odds ratio [OR], 0.94; P = .01), three fenestrations (OR, 42.7; P = .01) and the presence of augmented proximal rings (OR, 0.17; P = .03). Median follow-up was 1.2 years (interquartile range, 0.4-2.6). The mean estimated glomerular filtration rate deteriorated from 67.6 ± 19.3 mL/min/1.73 m² preoperatively to 59.3 ± 22.7 mL/min/1.73 m² at latest follow-up (P = .00). The freedom from AAA growth were 97.9 ± 0.9% (n = 190) and 86.4 ± 3.0% (n = 68), with a freedom from AAA rupture of 99.7 ± 0.3% (n = 191) and 99.1 ± 0.7% (n = 68), at 1 and 3 years, respectively. The endoleak-free survival, excluding spontaneously resolved procedural endoleaks, at 1 and 3 years was 73.4 ± 2.6 (n = 143) and 65.6 ± 3.4% (n = 45), respectively. The target vessel patency at one and three years were 96.4 ± 0.7% (n = 493) and 92.7 ± 1.4% (n = 156), respectively. A total of 75 reinterventions were done in 64 cases (19.1%), of which 25 cases for an endoleak. The reintervention-free survival at 1 and 3 years were 83.6 ± 2.2% (n = 190) and 71.0 ± 3.7% (n = 68), respectively. No deaths during procedure, extending within 24 hours postoperatively, were observed. Within 30 days 14 patients (4.2%) died and during follow-up another 39 patients (11.6%) died. Three deaths were considered AAA related (one rupture, one endograft infection, and one bilateral renal artery occlusion). The estimated cumulative survival at 1 and 3 years were 89.8 ± 1.8% (n = 191) and 79.2 ± 3.0% (n = 68), respectively.

CONCLUSIONS

The custom-made fenestrated Anaconda endograft is a valuable option for the treatment of a complex AAA. A procedural type IA endoleak is seen relatively frequently, but spontaneously resolves in most cases.

Quantitative Stent Graft Motion in ECG Gated CT by Image Registration and Segmentation: In Vitro Validation and Preliminary Clinical Results

OBJECTIVES

The dynamic endovascular environment of stent grafts may influence long term outcome after endovascular aneurysm repair (EVAR). The sealing and fixation of a stent graft to the aortic wall is challenged at every heartbeat, yet knowledge of the cardiac induced dynamics of stent grafts is sparse. Understanding the stent-artery interaction is crucial for device development and may aid the prediction of failure in the individual patient. The aim of this work was to establish quantitative stent graft motion in multiphasic electrocardiogram (ECG) gated computed tomography (CT) by image registration and segmentation techniques.

METHODS

Experimental validation was performed by evaluating a series of ECG gated CT scans of a stent graft moving at different amplitudes of displacement at different virtual heart rates using a motion generating device with synchronised ECG triggering. The methodology was further tested on clinical data of patients treated with EVAR devices with different stent graft designs. Displacement during the cardiac cycle was analysed for points on the fixating stent rings, the branches or fenestrations, and the spine.

RESULTS

Errors for the amplitude of displacement measured in vitro at individual points on the wire frame were at most 0.3 mm. In situ cardiac induced displacement of the devices was found to differ per location and also depended on the type of stent graft. Displacement during the cardiac cycle was greatest in a fenestrated device and smallest in a chimney graft sac anchoring endosystem, with maximum displacement varying from 0.0 to 1.4 mm. There was no substantial displacement measurable in the spine.

CONCLUSIONS

A novel methodology to quantify and visualise stent graft motion in multiphasic ECG gated CT has been validated in vitro and tested in vivo. This methodology enables further exploration of in situ motion of different stent grafts and branch stents and their interaction with native vessels.

[Cystic adventitial degeneration of the radial artery: wrist swelling of unexpected origin]

BACKGROUND Cystic adventitial degeneration (CAD) of an artery is a rare disease in which a mucinous cyst is formed in the adventitia. The condition usually occurs in the popliteal artery, but in rarer cases in arteries of the forearm, where it may lead to symptoms caused by local swelling or arterial occlusion. CASE DESCRIPTION A 54-year-old woman was referred by her general practitioner for a wrist swelling. This was initially thought to be caused by a ganglion but after ultrasound and MRI, it was found to be CAD of the radial artery. The symptoms recurred after transcutaneous aspiration of the cyst. This was followed by surgical resection with venous graft reconstruction. CONCLUSION In rare cases, swelling of the wrist is caused by CAD. Ultrasound and, if necessary, MRI will lead to a reliable diagnosis. Treatment consists of transcutaneous aspiration and, in case of recurrence, surgical resection.

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.

Outcomes After Drug-Coated Balloon Treatment of Femoropopliteal Lesions in Patients With Critical Limb Ischemia: A Post Hoc Analysis From the IN.PACT Global Study

Purpose: To report a post hoc analysis performed to evaluate 1-year safety and efficacy of the IN.PACT Admiral drug-coated balloon (DCB) for the treatment of femoropopliteal lesions in subjects with critical limb ischemia (CLI) enrolled in the IN.PACT Global study (ClinicalTrials.gov identifier NCT01609296). Materials and Methods: Of 1535 subjects enrolled in the study, 156 participants (mean age 71.8±10.4; 87 men) with CLI (Rutherford categories 4,5) were treated with DCB angioplasty in 194 femoropopliteal lesions. This cohort was compared to the 1246 subjects (mean age 68.2±10.0 years; 864 men) with intermittent claudication (IC) treated for 1573 lesions. The CLI cohort had longer lesions (13.9±10.6 vs 11.9±9.4 cm, p=0.009) and a higher calcification rate (76.8% vs 67.7%, p=0.011). Major adverse events [MAE; composite of all-cause mortality, clinically-driven target lesion revascularization (CD-TLR), major (above-ankle) target limb amputation, and thrombosis at the target lesion site], lesion and vessel revascularization rates, and EuroQol-5D were assessed through 1 year. The Kaplan-Meier method was used to estimate survival, CD-TLR, and amputation events; estimates are presented with the 95% confidence intervals (CI). Results: Estimates of 12-month freedom from major target limb amputation were 98.6% (95% CI 96.7% to 100.0%) in subjects with CLI and 99.9% (95% CI 99.8% to 100.0%) in subjects with IC (p=0.002). Freedom from CD-TLR through 12 months was 86.3% (95% CI 80.6% to 91.9%) in CLI subjects and 93.4% (95% CI 91.9% to 94.8%) in IC subjects (p<0.001). The MAE rate through 12 months was higher in CLI subjects (22.5% vs 10.7%, p<0.001), and CLI patients had poorer overall survival (93.0%, 95% CI 88.9% to 97.2%) than IC subjects (97.0%, 95% CI 96.0% to 97.9%, p=0.011). Health status significantly improved in all domains at 6 and 12 months in both groups. Conclusion: Treatment of femoropopliteal disease with DCB in CLI patients is safe through 12-month follow-up, with a low major amputation rate of 1.4%. The rates of MAE and CD-TLR were higher in CLI subjects and reinterventions were required sooner. Additional research is needed to evaluate long-term outcomes of DCB treatment for femoropopliteal lesions in CLI patients.

Secondary Endovascular Aneurysm (EVAS) Sealing in Combination With Chimney Grafts to Treat Failed Chimney EVAS

Purpose: To describe a proximal extension of a failed chimney endovascular aneurysm sealing repair (chEVAS) using a chEVAS-in-chEVAS procedure in 2 cases with successful treatment outcome at 2-year follow-up. Case Report: Two patients with an infrarenal abdominal aortic aneurysm were treated with an elective chEVAS procedure with 1 chimney stent for a unilateral renal artery. At 18 and 24 months, respectively, both patients showed aneurysm growth with an associated decrease in proximal seal. Both patients were treated with a secondary chEVAS procedure, consisting of chimney stent-graft placement in the contralateral renal and the superior mesenteric arteries combined with proximal extension of the in situ chimney stent-graft and the Nellix stents. Two-year follow-up demonstrated successful aneurysm exclusion with a patent stent configuration. Conclusion: A type Ia endoleak after chEVAS can be successfully repaired with a chEVAS-in-chEVAS procedure.

Secondary Endovascular Aneurysm (EVAS) Sealing in Combination With Chimney Grafts to Treat Failed Chimney EVAS

PURPOSE

To describe a proximal extension of a failed chimney endovascular aneurysm sealing repair (chEVAS) using a chEVAS-in-chEVAS procedure in 2 cases with successful treatment outcome at 2-year follow-up.

CASE REPORT

Two patients with an infrarenal abdominal aortic aneurysm were treated with an elective chEVAS procedure with 1 chimney stent for a unilateral renal artery. At 18 and 24 months, respectively, both patients showed aneurysm growth with an associated decrease in proximal seal. Both patients were treated with a secondary chEVAS procedure, consisting of chimney stent-graft placement in the contralateral renal and the superior mesenteric arteries combined with proximal extension of the in situ chimney stent-graft and the Nellix stents. Two-year follow-up demonstrated successful aneurysm exclusion with a patent stent configuration.

CONCLUSION

A type Ia endoleak after chEVAS can be successfully repaired with a chEVAS-in-chEVAS procedure.

High-Frame-Rate Contrast-Enhanced Ultrasound for Velocimetry in the Human Abdominal Aorta

Treatment of abdominal aortic (AA) aneurysms and stenotic lesions may be improved by analyzing their associated blood-flow patterns. Angle-independent blood-flow patterns in the AA can be obtained by combining echo-particle image velocimetry (ePIV) with high-frame-rate (HFR) contrast-enhanced ultrasonography. However, ePIV performance is affected by ultrasound contrast agent (UCA) concentration, microbubble stability, and tissue clutter. In this study, we assessed the influence of acoustic pressure and UCA concentration on image quality for ePIV analysis. We also compared amplitude modulation (AM) and singular value decomposition (SVD) as tissue suppression strategies for ePIV. Fourteen healthy volunteers were imaged in the region of the distal AA. We tested four different UCA bolus volumes (0.25, 0.5, 0.75, and 1.5 mL) and four different acoustic output pressures (mechanical indices: 0.01, 0.03, 0.06, and 0.09). As image quality metrics, we measured contrast-to-background ratio, bubble disruption ratio, and maximum normalized cross-correlation value during ePIV. At mechanical indices ≥ 0.06, we detected severe bubble destruction, suggesting that very low acoustic pressures should be used for ePIV. SVD was able to suppress tissue clutter better than AM. The maximum tracking correlation was affected by both UCA concentration and flow rate, where at high flow rates, lower UCA concentrations resulted in slightly higher correlation values but more signal drop-outs during late diastole. HFR ePIV was successfully performed in the AA of healthy volunteers and shows promise for future studies in patients.

Meta-analysis of Individual Patient Data After Kissing Stent Treatment for Aortoiliac Occlusive Disease

PURPOSE

To evaluate short- and long-term technical and clinical outcomes after kissing stent treatment of aortoiliac occlusive disease (AIOD) based on an individual participant data (IPD) meta-analysis.

MATERIALS AND METHODS

A search of the Scopus database identified 156 articles on KS treatment of AIOD; of these 22 met the inclusion criteria. Authors of 19 articles with contact information were approached to join an IPD consortium. Eight author groups responded and 5 provided anonymized data for merging into an IPD database. The number of included procedures was equal before and after 2005. The primary study outcome was the cumulative patency at 24 months. Secondary outcomes were patency at up to 60 months, complications, and changes in Rutherford category and ankle-brachial index. The predictive value of stent protrusion length, pre-/postdilation, stent type, and patient demographics on primary patency were examined with Cox proportional hazard modeling; outcomes are reported as the hazard ratio (HR). The Kaplan-Meier method was employed to estimate patency rates.

RESULTS

In total, 605 (40.9%) of 1480 patients presented in the literature were included in the IPD analysis. The indication for intervention was intermittent claudication in 84.2% and critical limb ischemia in 15.8%. Lesions were classified as TransAtlantic Inter-Society Consensus (TASC) A or B in 52.8% and TASC C and D in 47.2%. The overall primary patency estimate was 81% at 24 months. Primary patency significantly increased after 2005 (p=0.005). Cox regression analysis revealed only age as a significant predictor of sustained primary patency (HR 0.60, p<0.005). Any previous endovascular intervention (HR 2.52, p=0.02) was the main predictor for loss of secondary patency; history of cardiovascular disease (HR 0.27, p=0.04) was the main predictor of sustained secondary patency.

CONCLUSION

The kissing stent technique has a good safety profile and acceptable patency rates up to 2 years, even in TASC C and D lesions, supporting an endovascular-first approach for AIOD.

Mid- and Long-Term Outcome of Currently Available Endografts for the Treatment of Infrarenal Abdominal Aortic Aneurysm

Currently, there is a wide range of commercially available endografts for infrarenal abdominal aortic aneurysm (AAA) repair. Results of long-term follow up after endovascular aneurysm repair (EVAR) are limited. Thereby, the durability of these endografts and the difference between manufacturers is not fully clear. In this review, studies with mid- and long-term results, with a minimum median follow up of 36 months per endograft, were included describing results with Cook Zenith? Flex? endograft (Cook Medical Inc., Bloomington, Indiana) (n=6), Cordis Corporate INCRAFT? (Cordis Corporation, Freemont, California) (n=1), Gore? EXCLUDER? (W.L. Gore & Associates Inc., Flagstaff, Arizona) (n=3), Medtronic Endurant? (Medtronic plc, Santa Rosa, California) (n= 6), and Vascutek Anaconda? (Vascutek Ltd., Inchinnan, Scotland) (n=2). The assisted technical success varied between 83% and 100%, and the perioperative mortality, early reintervention, and early conversion rates were comparable for the studied endografts. At three-year follow up, the freedom from AAA-rupture and AAA-related death varied between 98% and 100%. The results demonstrated an increasing complication and reintervention rate over time. When adhering to the instruction for use, minor differences were seen during follow up between the endografts. Latest generation endografts continue to have good postoperative results, the reintervention-rate of 10-20% over time mandates an ongoing close patient follow up. The choice of a specific design depends on native patient anatomy and the experience of the implanting surgeon.

Anatomical Predictors of Endoleaks or Migration After Endovascular Aneurysm Sealing

Purpose: To identify preoperative anatomical aortic characteristics that predict seal failures after endovascular aneurysm sealing (EVAS) and compare the incidence of events experienced by patients treated within vs outside the instructions for use (IFU). Methods: Of 355 patients treated with the Nellix EndoVascular Aneurysm Sealing System (generation 3SQ+) at 3 high-volume centers from March 2013 to December 2015, 94 patients were excluded, leaving 261 patients (mean age 76±8 years; 229 men) for regression analysis. Of these, 83 (31.8%) suffered one or more of the following events: distal migration ⩾5 mm of one or both stent frames, any endoleak, and/or aneurysm growth >5 mm. Anatomical characteristics were determined on preoperative computed tomography (CT) scans. Patients were divided into 3 groups: treated within the original IFU (n=166), outside the original IFU (n=95), and within the 2016 revised IFU (n=46). Categorical data are presented as the median (interquartile range Q1, Q3). Results: Neck diameter was significantly larger in the any-event cohort vs the control cohort [23.7 mm (21.7, 26.3) vs 23.0 mm (20.9, 25.2) mm, p=0.022]. Neck length was significantly shorter in the any-event cohort [15.0 mm (10.0, 22.5) vs 19.0 mm (10.0, 21.8), p=0.006]. Maximum abdominal aortic aneurysm (AAA) diameter and the ratio between the maximum AAA diameter and lumen diameter in the any-event group were significantly larger than the control group (p=0.041 and p=0.002, respectively). Regression analysis showed aortic neck diameter (p=0.006), neck length (p=0.001), and the diameter ratio (p=0.011) as significant predictors of any event. In the comparison of events to IFU status, 52 (31.3%) of 166 patients in the inside the original IFU group suffered an event compared to 13 (28.3%) of 46 patients inside the 2016 IFU group (p=0.690). Conclusion: Large neck diameter, short aortic neck length, and the ratio between the maximum AAA and lumen diameters are preoperative anatomical predictors of the occurrence of migration (⩾5 mm), any endoleak, and/or aneurysm growth (>5 mm) after EVAS. Even under the refined 2016 IFU, more than a quarter of patients suffered from an event. Improvements in the device seem to be necessary before this technique can be implemented on a large scale in endovascular AAA repair.

Early results with the custom-made Fenestrated Anaconda aortic cuff in the treatment of complex abdominal aortic aneurysm

OBJECTIVE

The objective of this study was to investigate the feasibility of a specific custom-made fenestrated aortic cuff in the treatment of complex abdominal aortic aneurysms (AAAs).

METHODS

Between 2013 and 2016, a total of 57 custom-made Fenestrated Anaconda (Vascutek, Inchinnan, Scotland, UK) aortic cuffs were placed in 38 centers worldwide. All centers were invited to participate in this retrospective analysis. Postoperative and follow-up data included the presence of adverse events, necessity for reintervention, and renal function.

RESULTS

Fifteen clinics participated, leading to 29 cases. Median age at operation was 74 years (interquartile range [IQR], 71-78 years); five patients were female. Two patients were treated for a para-anastomotic AAA after open AAA repair, 19 patients were treated because of a complicated course after primary endovascular AAA repair, and 8 cases were primary procedures for AAA. A total of 76 fenestrations (mean, 2.6 per case) were used. Four patients needed seven adjunctive procedures. Two patients underwent conversion, one because of a dissection of the superior mesenteric artery and one because of perforation of a renal artery. Median operation time was 225 minutes (IQR, 150-260 minutes); median blood loss, 200 mL (IQR, 100-500 mL); and median contrast volume, 150 mL (IQR, 92-260 mL). Primary technical success was achieved in 86% and secondary technical success in 93%. The 30-day morbidity was 7 of 29 with a mortality rate of 4 of 29. Estimated glomerular filtration rate remained unchanged before and after surgery (76 to 77 mL/min/m²). Between preoperative and median follow-up of 11 months, estimated glomerular filtration rate was reduced statistically significantly (76 to 63 mL/min/m²). During follow-up, 9 cases had an increase in aneurysm sac diameter (5 cases >5 mm); 14 cases had a stable or decreased aneurysm sac diameter; and in 2 cases, no aneurysm size was reported. No type I endoleak was reported, and two cases with a type III endoleak were treated by endovascular means during follow-up. Survival, reintervention-free survival, and target vessel patency at 1 year were 81% ± 8%, 75% ± 9%, and 99% ± 1%, respectively. After 2 years, these numbers were 81% ± 8%, 67% ± 11%, and 88% ± 6%, respectively. During follow-up, the two patients with a type III endoleak needed endograft-related reinterventions.

CONCLUSIONS

Treatment with this specific custom-made fenestrated aortic cuff is feasible after complicated previous (endovascular) aortic repair or in complex AAAs. The complexity of certain AAA cases is underlined in this study, and the Fenestrated Anaconda aortic cuff is a valid option in selected cases in which few treatment options are left.

High-Frame-Rate Contrast-enhanced US Particle Image Velocimetry in the Abdominal Aorta: First Human Results

Purpose To study the feasibility of high-frame-rate (HFR) contrast material-enhanced (CE) ultrasound particle image velocimetry (PIV), or echo PIV, in the abdominal aorta. Materials and Methods Fifteen healthy participants (six men; median age, 23 years [age range, 18-34 years]; median body mass index, 20.3 kg/m² [range, 17.3-24.9 kg/m²]) underwent HFR CE US. US microbubbles were injected at incremental doses (0.25, 0.5, 0.75, and 1.5 mL), with each dose followed by US measurement to determine the optimal dosage. Different US mechanical index values were evaluated (0.09, 0.06, 0.03, and 0.01) in a diverging wave acquisition scheme. PIV analysis was performed via pairwise cross-correlation of all captured images. Participants also underwent phase-contrast MRI. The echo PIV and phase-contrast MRI velocity profiles were compared via calculation of similarity index and relative difference in peak velocity. Results Visualization of the aortic bifurcation with HFR CE US was successful in all participants. Optimal echo PIV results were achieved with the lowest contrast agent dose of 0.25 mL in combination with the lowest mechanical indexes (0.01 or 0.03). Substantial bubble destruction occurred at higher mechanical indexes (≥0.06). Flow patterns were qualitatively similar in the echo PIV and MR images. The echo PIV and MRI velocity profiles showed good agreement (similarity index, 0.98 and 0.99; difference in peak velocity, 8.5% and 17.0% in temporal and spatial profiles, respectively). Conclusion Quantification of blood flow in the human abdominal aorta with US particle image velocimetry (echo PIV) is feasible. Use of echo PIV has potential in the clinical evaluation of aortic disease. © RSNA, 2018 Online supplemental material is available for this article.

Apposition and Positioning of the Nellix EndoVascular Aneurysm Sealing System in the Infrarenal Aortic Neck

PURPOSE

To investigate the initial proximal position and seal of the Nellix EndoVascular Aneurysm Sealing (EVAS) system in the aortic neck using a novel methodology.

METHODS

Forty-six consecutive patients who underwent elective EVAS for an abdominal aortic aneurysm were retrospectively selected and dichotomized into an early (n=23) and a late (n=23) group. The aortic neck morphology and aortic neck surface (ANS) were determined on preoperative computed tomography (CT) scans; the endograft position and nonapposition surface (NAS) were determined on the 1-month CT scans. The position of the proximal endobag boundary was measured by 2 experienced observers to analyze the interobserver variability for the EVAS NAS measurements. The shortest distance from the lowest renal artery to the endobag (shortest fabric distance) and the shortest distance from the endobag to the end of the infrarenal neck (shortest sealing distance) were determined. The intraclass correlation coefficients (ICCs) are presented with the 95% confidence interval (CI). Continuous data are presented as the median and interquartile range (IQR: Q3 - Q1).

RESULTS

There were no differences between the early and late EVAS groups regarding aortic neck morphology except for the neck calcification circumference [41° (IQR 33°) vs 87° (IQR 60°), respectively; p=0.043]. Perfect agreement was observed for the NAS (ICC 0.897, 95% CI 0.780 to 0.956). The NAS as a percentage of the preoperative ANS was 47% (IQR 43) vs 49% (IQR 49) for the early vs late groups, respectively (p=0.214). The shortest fabric distances were 5 mm (IQR 5) and 4 mm (IQR 7) for the early and late groups, respectively (p=0.604); the shortest sealing distances were 9 mm (IQR 13) and 16 mm (IQR 17), respectively (p=0.066).

CONCLUSION

Accurate positioning of the Nellix EVAS system in the aortic neck may be challenging. Despite considerable experience with the system, still around half of the potential seal in the aortic neck was missed in the current series, without improvement over time. This should be considered during preoperative planning and may be a cause of a higher than expected complication rate. Detailed post-EVAS nonapposition surface can be determined with the described novel methodology that takes into account the sometimes irregularly shaped top of the sealing endobags.

Two-Year Outcomes of the Nellix EndoVascular Aneurysm Sealing System for Treatment of Abdominal Aortic Aneurysms

Purpose: To analyze the 2-year outcomes of endovascular aneurysm sealing (EVAS) according to 2 versions of the instructions for use (IFU). Methods: A retrospective study was conducted involving 355 consecutive patients treated with the first-generation EVAS device from April 2013 to December 31, 2015, at 3 high-volume centers. Out of 355 patients treated with EVAS, 264 were elective asymptomatic infrarenal EVAS procedures suitable for analysis. In this cohort, 168 (63.3%) patients were treated within the IFU 2013 criteria; of these 48 (18.2%) were in compliance with the revised IFU 2016 version. Results: Overall technical success was 98.2% (165/168) in the IFU 2013 group and 97.9% (47/48) in the IFU 2016 subgroup (p=0.428). The 2-year freedom from reintervention estimates were 89.7% (IFU 2013) and 95.7% (IFU 2016), with significantly more reinterventions in the first 45 cases (p=0.005). The stenosis/occlusion estimates were 6.5% (IFU 2013) and 4.2% (IFU 2016; p=0.705). Nine (5.4%) endoleaks (8 type Ia and 1 type Ib) were observed within the IFU 2013 cohort; 3 (2.1%) were in the IFU 2016 subgroup (p=0.583). Migration ≥10 mm or ≥5 mm requiring intervention was reported in 12 (7.1%) patients in the IFU 2013 cohort but none within the IFU 2016 subgroup. Ten (6.0%) patients demonstrated aneurysm growth in the IFU 2013 cohort, of which 2 (4.2%) were in the IFU 2016 subgroup. Overall survival and freedom from aneurysm-related death estimates at 2 years were 90.9% and 97.6% in the IFU 2013 cohort (IFU 2016: 95.5% and 100.0%). The prevalence of complications seemed lower within IFU 2016 without significant differences. Conclusion: This study shows acceptable 2-year results of EVAS used within the IFU, without significant differences between the 2 IFU versions, though longer follow-up is indicated. The refined IFU significantly reduced the applicability of the technique.

Determination of Endograft Apposition, Position, and Expansion in the Aortic Neck Predicts Type Ia Endoleak and Migration After Endovascular Aneurysm Repair

Purpose: To describe the added value of determining changes in position and apposition on computed tomography angiography (CTA) after endovascular aneurysm repair (EVAR) to detect early caudal displacement of the device and to prevent type Ia endoleak. Methods: Four groups of elective EVAR patients were selected from a dataset purposely enriched with type Ia endoleak and migration (>10 mm) cases. The groups included cases of late type Ia endoleak (n=36), migration (n=9), a type II endoleak (n=16), and controls without post-EVAR complications (n=37). Apposition of the endograft fabric with the aortic neck, shortest distance between the fabric and the renal arteries, expansion of the main body (or dilatation of the aorta in the infrarenal sealing zone), and tilt of the endograft toward the aortic axis were determined on the first postoperative and the last available CTA scan without type Ia endoleak or migration. Differences in these endograft dimensions were compared between the first vs last scan and among the 4 groups. Results: No significant differences in endograft configurations were observed among the groups on the first postoperative CTA scan. On the last CTA scan before a complication arose, the position of the fabric relative to the renal arteries, expansion of the main body, and apposition of the fabric with the aortic neck were significantly different between the type Ia endoleak (median follow-up 15 months) and migration groups (median follow-up 23 months) compared with the control group (median follow-up 19 months). Most endograft dimensions had changed significantly compared with the first postoperative CTA scan for all groups. Apposition had increased in the control group but had decreased significantly in the type Ia endoleak and migration groups. Conclusion: Progressive changes in dimensions of the endograft within the infrarenal neck could be detected on regular CTA scans before the complication became urgent in many patients.

In Vitro Quantification of Gutter Formation and Chimney Graft Compression in Chimney EVAR Stent-Graft Configurations Using Electrocardiography-Gated Computed Tomography

Purpose: To assess the dynamic behavior of chimney grafts during the cardiac cycle. Methods: Three chimney endovascular aneurysm repair (EVAR) stent-graft configurations (Endurant and Advanta V12, Endurant and Viabahn, and Endurant and BeGraft) were placed in silicone aneurysm models and subjected to physiologic flow. Electrocardiography (ECG)-gated contrast-enhanced computed tomography was used to visualize geometric changes during the cardiac cycle. Endograft and chimney graft surface, gutter volume, chimney graft angulation over the center lumen line, and the D-ratio (the ratio between the lengths of the major and minor axes) were independently assessed by 2 observers at 10 time points in the cardiac cycle. Results: Both gutter volumes and chimney graft geometry changed significantly during the cardiac cycle in all 3 configurations (p<0.001). Gutters and endoleaks were observed in all configurations. The largest gutter volume (232.8 mm3) and change in volume (20.7 mm3) between systole and diastole were observed in the Endurant-Advanta configuration. These values were 2.7- and 3.0-fold higher, respectively, compared to the Endurant-Viabahn configuration and 1.7- and 1.6-fold higher as observed in the Endurant-BeGraft configuration. The Endurant-Viabahn configuration had the highest D-ratio (right, 1.26–1.35; left, 1.33–1.48), while the Endurant-BeGraft configuration had the lowest (right, 1.11–1.17; left, 1.08–1.15). Assessment of the interobserver variability showed a high correlation (intraclass correlation >0.935) between measurements. Conclusion: Gutter volumes and stent compression are dynamic phenomena that reshape during the cardiac cycle. Compelling differences were observed during the cardiac cycle in all configurations, with the self-expanding (Endurant–Viabahn) chimney EVAR configurations having smaller gutters and less variation in gutter volume during the cardiac cycle yet more stent compression without affecting the chimney graft surface.

Editor's Choice - Occurrence and Classification of Proximal Type I Endoleaks After EndoVascular Aneurysm Sealing Using the Nellix™ Device

OBJECTIVE/BACKGROUND

Proximal type I endoleaks are associated with abdominal aortic aneurysm (AAA) growth and rupture and necessitate repair. The Nellix™ EndoVascular Aneurysm Sealing (EVAS) system is a unique approach to AAA repair, where the appearance and treatment of endoleaks is also different. This study aimed to analyse and categorise proximal endoleaks in an EVAS treated cohort.

METHODS

All patients, treated from February 2013 to December 2015, in 15 experienced EVAS centres, presenting with proximal endoleak were included. Computed tomography scans were analysed by a core laboratory. A consensus meeting was organised to discuss and qualify each case for selection, technical aspects, and possible causes of the endoleak. Endoleaks were classified using a novel classification system for EVAS.

RESULTS

During the study period 1851 patients were treated using EVAS at 15 centres and followed for a median of 494 ± 283 days. Among these, 58 cases (3.1%) developed a proximal endoleak (1.5% early and 1.7% late); of these, 84% of 58 patients were treated outside the original and 96% outside the current, refined, instructions for use. Low stent positioning was the most likely cause in 44.6%, a hostile anatomy in 16.1%, and a combination of both in 33.9%. Treatment, by embolisation or proximal extension, was performed in 47% of cases, with a technical success of 97%.

CONCLUSION

The overall incidence of proximal endoleak after EVAS is 3.1% after a mean follow-up period of 16 months, with 1.5% occurring within 30 days. Their occurrence is related to patient selection and stent positioning. Early detection and classification is crucial to avoid the potential of sac rupture.

The Influence of Positioning of the Nellix Endovascular Aneurysm Sealing System on Suprarenal and Renal Flow: An In Vitro Study

Purpose: To examine the influence of device positioning and infrarenal neck diameter on flow patterns in the Nellix endovascular aneurysm sealing (EVAS) system. Methods: The transition of the aortic flow lumen into two 10-mm-diameter stents after EVAS creates a mismatched area. Flow recirculation may affect local wall shear stress (WSS) profiles and residence time associated with atherosclerosis and thrombosis. To examine these issues, 7 abdominal aortic aneurysm flow phantoms were created, including 3 unstented controls and 3 stented models with infrarenal neck diameters of 24, 28, and 32 mm. Stents were positioned within the instructions for use (IFU). Another 28-mm model was created to evaluate lower positioning of the stents outside the IFU (28-mm LP). Flow was visualized using optical particle imaging velocimetry (PIV) and quantified by time-averaged WSS (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) in the aorta at the anteroposterior (AP) midplane, lateral midplane, and renal artery AP midplane levels. Results: Flow in the aorta AP midplane was similar in all models. Vortices were observed in the stented models in the lateral midplane near the anterior and posterior walls. In the 32-mm IFU and 28-mm LP models, a steady state of vortices appeared, with varying location during a cycle. In all models, a low TAWSS (<10−2 Pa) was observed at the anterior wall of the aorta with peak OSI of 0.5 and peak RRT of 104 Pa−1. This region was more proximally located in the stented models. The 24- and 28-mm IFU models showed flow with a higher velocity at the renal artery inflow compared to controls. TAWSS in the renal artery was lower near the orifice in all models, with the largest area in the 24-mm IFU model. OSI and RRT in the renal artery were near zero for all models. Conclusion: EVAS enhances vorticity proximal to the seal zone, especially with lower positioning of the device and in larger neck diameters. Endobags just below the renal artery affect the flow profile in a minor area of this artery in 24- and 28-mm necks, while lower stent positioning does not influence the renal artery flow profile.

The Influence of Positioning of the Nellix Endovascular Aneurysm Sealing System on Suprarenal and Renal Flow: An In Vitro Study

PURPOSE

To examine the influence of device positioning and infrarenal neck diameter on flow patterns in the Nellix endovascular aneurysm sealing (EVAS) system.

METHODS

The transition of the aortic flow lumen into two 10-mm-diameter stents after EVAS creates a mismatched area. Flow recirculation may affect local wall shear stress (WSS) profiles and residence time associated with atherosclerosis and thrombosis. To examine these issues, 7 abdominal aortic aneurysm flow phantoms were created, including 3 unstented controls and 3 stented models with infrarenal neck diameters of 24, 28, and 32 mm. Stents were positioned within the instructions for use (IFU). Another 28-mm model was created to evaluate lower positioning of the stents outside the IFU (28-mm LP). Flow was visualized using optical particle imaging velocimetry (PIV) and quantified by time-averaged WSS (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) in the aorta at the anteroposterior (AP) midplane, lateral midplane, and renal artery AP midplane levels.

RESULTS

Flow in the aorta AP midplane was similar in all models. Vortices were observed in the stented models in the lateral midplane near the anterior and posterior walls. In the 32-mm IFU and 28-mm LP models, a steady state of vortices appeared, with varying location during a cycle. In all models, a low TAWSS (<10^-2 Pa) was observed at the anterior wall of the aorta with peak OSI of 0.5 and peak RRT of 10⁴ Pa^-1. This region was more proximally located in the stented models. The 24- and 28-mm IFU models showed flow with a higher velocity at the renal artery inflow compared to controls. TAWSS in the renal artery was lower near the orifice in all models, with the largest area in the 24-mm IFU model. OSI and RRT in the renal artery were near zero for all models.

CONCLUSION

EVAS enhances vorticity proximal to the seal zone, especially with lower positioning of the device and in larger neck diameters. Endobags just below the renal artery affect the flow profile in a minor area of this artery in 24- and 28-mm necks, while lower stent positioning does not influence the renal artery flow profile.

Mechanochemical endovenous ablation of saphenous veins using the ClariVein: A systematic review

Objective To systematically review all available English literature on mechanochemical endovenous ablation and to report on the anatomical, technical, and clinical success. Methods A systematic literature search was performed in PubMed, EMBASE, and the Cochrane Library on mechanochemical endovenous ablation for the treatment of insufficient great and/or small saphenous vein. Methodological quality of the included studies was evaluated using the MINORS score. The primary outcome measure was anatomical success, defined as closure of the treated vein on follow-up duplex ultrasound imaging. Secondary outcomes were technical and clinical success, and major complications defined as deep venous thrombosis, pulmonary embolisms or paresthesia. Results The literature search identified 759 records, of which 13 were included, describing 10 unique cohorts. A total of 1521 veins (1267 great saphenous vein and 254 small saphenous vein) were included, with cohort sizes ranging from 30 to 570 veins. The pooled anatomical success rate after short-term follow up was 92% (95% CI 90-94%) ( n = 1314 veins). After 6 and 12 months these numbers were 92% (95% CI 88-95%) ( n = 284) and 91% (95% CI 86-94%) ( n = 228), respectively. The long-term anatomical success rates at 2 and 3 years were 91% (95% CI 85-95%) ( n = 136) and 87% (95% CI 75-94%) ( n = 48), respectively. Major complications and especially nerve injury were very rare (≤ 0.2%). All studies were of moderate or good quality using the MINORS scoring scale. Conclusions Mechanochemical endovenous ablation using the ClariVein in combination with liquid sclerosant is associated with an anatomical success rate ranging from 87% to 92% and good clinical success. To date, no randomized controlled trials are available studying the anatomical success after mechanochemical ablation, compared to the endothermal ablation. The risk of major complications is very low after the procedure.

Flow and wall shear stress characterization after endovascular aneurysm repair and endovascular aneurysm sealing in an infrarenal aneurysm model

BACKGROUND

Endovascular aneurysm repair (EVAR) with a modular endograft has become the preferred treatment for abdominal aortic aneurysms. A novel concept is endovascular aneurysm sealing (EVAS), consisting of dual endoframes surrounded by polymer-filled endobags. This dual-lumen configuration is different from a bifurcation with a tapered trajectory of the flow lumen into the two limbs and may induce unfavorable flow conditions. These include low and oscillatory wall shear stress (WSS), linked to atherosclerosis, and high shear rates that may result in thrombosis. An in vitro study was performed to assess the impact of EVAR and EVAS on flow patterns and WSS.

METHODS

Four abdominal aortic aneurysm phantoms were constructed, including three stented models, to study the influence of the flow divider on flow (Endurant [Medtronic, Minneapolis, Minn], AFX [Endologix, Irvine, Calif], and Nellix [Endologix]). Experimental models were tested under physiologic resting conditions, and flow was visualized with laser particle imaging velocimetry, quantified by shear rate, WSS, and oscillatory shear index (OSI) in the suprarenal aorta, renal artery (RA), and common iliac artery.

RESULTS

WSS and OSI were comparable for all models in the suprarenal aorta. The RA flow profile in the EVAR models was comparable to the control, but a region of lower WSS was observed on the caudal wall compared with the control. The EVAS model showed a stronger jet flow with a higher shear rate in some regions compared with the other models. Small regions of low WSS and high OSI were found near the distal end of all stents in the common iliac artery compared with the control. Maximum shear rates in each region of interest were well below the pathologic threshold for acute thrombosis.

CONCLUSIONS

The different stent designs do not influence suprarenal flow. Lower WSS is observed in the caudal wall of the RA after EVAR and a higher shear rate after EVAS. All stented models have a small region of low WSS and high OSI near the distal outflow of the stents.

Collateral artery pathways of the femoral and popliteal artery

BACKGROUND

The role of collateral artery circulation in the lower limb is under debate but clinically relevant, particularly when using covered stents for occlusive disease. Covered stents seem to outperform nitinol stents in extensive disease, but collaterals could be essential in case of acute thrombosis. In the present study, we describe the collateral pathways of the deep and superficial femoral artery (DFA, SFA) and the popliteal artery (PA), observed in human cadavers.

METHODS

Ten fresh frozen cadaver legs were selected. The SFA and DFA were separately cannulated and injected with a different colored latex mixture simultaneously. After curing of the latex, the circulation was dissected thus visualizing the main arteries and their collateral vessels. The process was photographed and recorded, and collateral pathways were analyzed using a standardized vessel segmentation. The upper leg was divided in three regions, that is, the femoral triangle (F), the adductor canal (H), and the popliteal fossa (P) that, in turn, were split in three segments (1, 2, and 3, from proximal to distal).

RESULTS

Overall, 113 collateral vessels were found; 69 originated from the DFA, 34 from the SFA, and 10 from the PA. The majority of collaterals originating from the DFA terminated in the SFA (57%). Fifty-six of 113 collaterals (50%) ended in either the distal adductor channel (H3) or the proximal PA (P1). Another 28 collateral arteries (25%) had their origin in this segment (H3, P1) and mostly connected to the P2 and P3 segments. Forty-three collaterals of the DFA and H3 segment had a direct or indirect connection to below the knee muscles.

CONCLUSIONS

The majority of collaterals originate from the DFA, and the greater part of all collaterals has a connection with the H3-P1 segment. This observation may have clinical implications in the planning of endovascular procedures.

One-year pivotal trial outcomes of the Nellix system for endovascular aneurysm sealing

OBJECTIVE

The Nellix EndoVascular Aneurysm Sealing (EVAS) System (Endologix, Inc, Irvine, Calif) is a novel approach to abdominal aortic aneurysm (AAA) treatment whereby polymer is used to fill the AAA sac. We report 1-year results of the investigational device exemption pivotal trial.

METHODS

Eligible patients were treated at 30 sites in the United States and Europe. Inclusion criteria required an asymptomatic infrarenal AAA, with a neck length ≥10 mm and ≤60° angle, iliac artery blood lumen diameter 9 to 35 mm, access artery diameter ≥6 mm, and serum creatinine ≤2 mg/dL. Follow-up included computed tomography angiography scans at 30 days, 6 months, and 1 year that were evaluated by a core laboratory. The primary safety end point was 30-day major adverse events (MAEs), which were compared with a performance goal of <56% (the Society for Vascular Surgery open repair control group rate). The primary effectiveness end point was treatment success at 1 year, which was compared with a performance goal of >80%. Treatment success required procedural technical success and absence of AAA rupture during follow-up, conversion to open surgical repair, endoleak (type I or III) at 1 year, migration >10 mm causing complications or requiring secondary intervention, aneurysm enlargement, or secondary procedures through 1 year for resolution of endoleak, device obstruction or occlusion, or device defect.

RESULTS

Of 150 treated patients, 149 (99.3%) completed 1-year follow-up. The MAEs rate at 30 days was 2.7% (95% confidence interval, 0.7%-6.7%), satisfying the primary safety end point (<56%). The 1-year treatment success was 94% (95% confidence interval, 88.6%-97.4%), achieving the primary effectiveness end point (>80%). At 1 year, key secondary outcomes included 6.7% MAEs, 4.7% serious device-related events, 1.3% AAA-related mortality, 3.7% secondary interventions, and 0.7% surgical conversions. MAEs through 1 year included death (n = 6), stroke (n = 3), bowel ischemia (n = 2), renal failure (n = 2), respiratory failure (n = 2), and myocardial infarction (n =1). One iatrogenic AAA rupture occurred and one AAA rupture was reported during follow-up. AAA sac enlargement (>5 mm) was 1.5% at 1 year. Endoleaks were present in four patients (3.1%) at 1 year (1 type Ib and 3 type II). Migration >10 mm occurred in three patients (2.3%), but none required secondary intervention.

CONCLUSIONS

Outcomes with this novel endovascular therapy for AAA, the Nellix EVAS System, are encouraging. The primary safety and effectiveness end points have been met. Low morbidity, low mortality, and high procedural and treatment success were achieved despite the inevitability of a learning curve and unique risks associated with a new device and technique. Long-term follow-up is in progress.

Feasibility and Technical Aspects of Proximal Nellix-in-Nellix Extension for Late Caudal Endograft Migration

Purpose: To describe the feasibility and technical aspects of a proximal Nellix-in-Nellix extension to treat caudal stent-graft migration after endovascular aneurysm sealing (EVAS) in the in vitro and in vivo settings. Methods: In vitro studies were designed (1) to assess inner diameters of Nellix-in-Nellix extensions after postdilation with 12-mm balloons and (2) to test wall apposition in tubes with different diameters using a Nellix-in-Nellix stent-graft that extended out of the original Nellix stent-graft lumen by 10, 20, 30, and 40 mm. Simulated-use experiments were performed using silicone models in conjunction with a pulsatile flow pump. In the clinical setting, 5 patients (median age 74 years, range 73–83) presented at 2 centers with type Ia endoleak secondary to caudal Nellix stent-graft migration measuring a median 9 mm (range 7–15) on the left and 7 mm (range 0-11) on the right. Median polymer fill volume at the initial EVAS procedure was 42.5 mL (range 25–71). The median time to reintervention with a proximal Nellix extension was 15 months (range 13–32). Results: In vitro, the inner diameters of the Nellix-in-Nellix extensions were consistent after postdilation. Cases with 10 and 20 mm of exposed endobag resulted in a poor seal with endoleak, while cases with 30 and 40 mm of exposed endobag length exhibited angiographic seal. Fill line pressures of the second Nellix were higher than expected. In the 5 clinical cases, chimney grafts were required in each case to create an adequate proximal landing zone. The Nellix-in-Nellix procedure was successful in all patients. There were no procedure-related complications, and no endoleaks were observed during a median 12-month follow-up. Reinterventions were performed in 2 patients because of in-stent stenosis and chimney graft compression, respectively. Conclusion: Proximal Nellix-in-Nellix extension can be used to treat caudally migrated Nellix stent-grafts and to treat the consequent type Ia endoleak, but the technique differs from primary EVAS. The development of dedicated proximal extensions is desirable.

Classification of gutter type in parallel stenting during endovascular aortic aneurysm repair

OBJECTIVE

Gutters can be described as the loss of continuous apposition between the main body of the endograft, the chimney stent graft, and the aortic wall. Gutters have been associated with increased risk of type IA endoleaks and are considered to be the Achilles' heel of chimney endovascular aneurysm repair (ch-EVAR). However, there is no classification yet to classify and quantify gutter types after ch-EVAR.

METHODS

Different gutter types can be distinguished by their morphologic appearance in two- and three-dimensional views and reconstructed slices perpendicular to the center lumen line.

RESULTS

Three main categories are defined by (1) the most proximal beginning of the gutter, (2) the length of gutter alongside the endograft, and (3) its distal end. Type A gutters originate at the proximal fabric of an endograft, type B gutters originate as loss of apposition of the chimney stent graft in the branch vessel, and type C gutters start below the fabric of the endograft. To determine eventual changes of gutter size during follow-up computed tomography angiograms (CTAs), measurements may be performed with dedicated software on the follow-up CTA scan to assess the extent of gutters over the aortic circumference, ranging from 0° to 360° of freedom, together with the maximum gap between the endograft material and the aortic wall as it appears on reconstructed axial CTA scan slices.

CONCLUSIONS

The proposed gutter classification enables a uniform nomenclature in the current ch-EVAR literature and a more accurate risk assessment of gutter-associated endoleaks. Moreover, it allows monitoring of eventual progression of gutter size during follow-up.

Midterm Outcome of Mechanochemical Endovenous Ablation for the Treatment of Great Saphenous Vein Insufficiency

PURPOSE

To report the midterm results of mechanochemical ablation (MOCA) for treating great saphenous vein (GSV) insufficiency.

METHODS

In a 1-year period, 85 consecutive patients (median age 51.4 years; 71 women) undergoing MOCA with polidocanol in 104 limbs were enrolled in a prospective registry. The patients were evaluated at baseline and during follow-up (4 weeks and 1, 2, and 3 years) using duplex ultrasound, the CEAP (clinical, etiologic, anatomic and pathophysiologic) classification, the Venous Clinical Severity Score (VCSS), the RAND Short Form 36-Item Health Survey (RAND-SF36), and the Aberdeen Varicose Vein Questionnaire (AVVQ). Primary outcome measures were clinical and anatomic success. Secondary outcome measures included general and disease-specific quality of life and reinterventions.

RESULTS

Technical success (99%) was achieved in all but 1 patient in whom technical problems with the device led to conversion to another method for treatment of 2 limbs. After a median follow-up of 36 months (interquartile range 12.5, 46.3), recanalization occurred in 15 (15%) of 102 successfully treated vein segments. Anatomic success was 92%, 90%, and 87% after 1, 2, and 3 years, respectively. The VCSS improved at all time intervals compared to the preprocedure median. The clinical success at 3 years was 83%. The AVVQ and RAND-SF36 scores showed an improvement at all time intervals compared to baseline values. Between 12 and 36 months, however, a significant deterioration was observed in VCSS, which was accompanied by worsening of disease-specific and general quality of life.

CONCLUSION

In the longest follow-up of MOCA to date, this study shows MOCA to be an effective treatment modality for GSV insufficiency at midterm follow-up, but clinical results seem to drop over time.

Initial Experience With Covered Endovascular Reconstruction of the Aortic Bifurcation in Conjunction With Chimney Grafts

PURPOSE

To show feasibility of the covered endovascular repair of the aortic bifurcation (CERAB) technique in conjunction with chimney grafts in aortic side branches for complex aortoiliac occlusive disease.

METHODS

Two European centers and one facility located in New Zealand participated in a retrospective observational study that enrolled 14 consecutive patients (mean age 61.2±8.9 years; 11 men) treated with CERAB in conjunction with chimney graft(s) between December 2012 and May 2015. Indications for treatment included disabling claudication in 9 and critical limb ischemia in 5. Lesions were classified as TransAtlantic Inter-Society Consensus II B (n=1), C (n=1), or D (n=12).

RESULTS

A total of 15 chimney grafts were used to perfuse the inferior mesenteric artery (n=8), the right renal artery (n=4), and the left renal artery (n=3). Technical success was achieved in all cases. Procedural complications included 5 unintended dissections and 1 vessel thrombosis, all of which were successfully treated intraoperatively. Five patients developed access-site hematoma/ecchymosis (3 at the brachial access). Mean follow-up was 12 months (range 6-24) without death or loss to follow-up. One patient suffered occlusion of a CERAB limb and an IMA chimney graft; the former was recanalized, but the IMA graft was not; there were no signs of bowel ischemia. Ankle-brachial indices significantly increased from 0.54 (range 0.47-0.60) preoperatively to 0.97 (range 0.90-1.00) in 11 patients examined at 12 months, and all patients had an improvement in the Rutherford category. All CERAB limbs, including the one recanalized, were patent at the most recent follow-up, as were 14 of 15 chimney grafts.

CONCLUSION

Chimney-CERAB is technically feasible and may offer an alternative to open surgery for complex aortoiliac occlusive disease. Further prospective studies are needed to confirm these findings.

Morbidity of femoropopliteal bypass surgery

A systemic review of published reports on the incidence of early (<30 days) adverse events occurring after above- or below-knee femoropopliteal bypass surgery was conducted to provide contemporary outcomes data for comparative reporting. A total of 38 articles were included describing 6,374 femoropopliteal bypasses in 6,007 patients. Fifty-two percent were male and the mean age was 64.6 years (range, 40 to 93 years). The various studied types of complications were reported in 10 to 34 of 38 articles and definitions were often missing. The overall 30-day morbidity rate was 36.8%. The wound infection rate was 7.8% (range, 0.0 to 17.4%) accompanied with dermal necrosis in 0.4%. Graft infection was described in 2.4% (range, 0.0 to 5.3%) of cases. Postoperative bleeding was seen in 7.4% (range, 0.0 to 26%), of which 2.5% required return to surgery. Occlusions were reported in 12.0% (range, 0.0 to 59%). Lymphedema occurred in 2.9% (range, 0.0 to 9.6%) of cases and surgical site seroma formation occurred in 2.0% (range, 1.0% to 3.0%). Overall 30-day mortality rate was 2.3% (range 0.0 to 4.3%). Pooled data comparing vein grafts and prosthetic grafts revealed no significant difference (P = .10; risk ratio = 0.82; 95% confidence interval, 0.66-1.03; I(2) = 0%) in the incidence of complications. This review confirmed the morbidity of femoropopliteal bypass surgery is inconsistently reported and definitions are lacking. Because one-third of patients can be expected to experience an adverse event after femoropopliteal bypass grafting, standards on defining and reporting complications are necessary if comparative outcome standards are developed.

Endovascular Aneurysm Sealing: Early and Midterm Results From the EVAS FORWARD Global Registry

PURPOSE

To report the early and 12-month results of a global registry of patients treated with endovascular aneurysm sealing (EVAS) for abdominal aortic aneurysms (AAAs).

METHODS

The EVAS FORWARD Global Registry was a postmarket, multicenter, open-label, single-arm registry that enrolled 277 patients (mean age 75 years; 228 men) treated with the Nellix EVAS system for nonruptured AAAs at 18 sites over a 1-year period. The cohort had challenging aortic anatomy, with 17% having a proximal aortic neck length <10 mm, 8% a neck angulation >60°, and 20% an iliac diameter >25 mm. Baseline and follow-up computed tomography images were assessed by an independent core laboratory, and major adverse events were reviewed by an independent safety committee.

RESULTS

Three patients died within 30 days of the procedure (none device-related). There were 13 endoleaks recorded in this time frame: 8 type Ia, 1 type Ib, and 5 type II. Root cause analysis demonstrated that the majority of type Ia endoleaks were due to technical error (low device placement and underfilling of the endobags). Between 30 days and 1 year, there were 4 new type Ia endoleaks; all were treated. There was also 1 type III endoleak between a Nellix device and a distal extension limb. At 1 year, the persistent endoleak rate was 0.7% (1 type Ia and 1 type II). The Kaplan-Meier estimates of freedom from types I and II endoleak at 12-month follow-up were 96% and 98%, respectively. The estimate of freedom from open conversion (n=7) was 98% at 12 months and the rate of freedom from any reintervention was 92%. The need for secondary intervention was associated with aortic morphology; for patients meeting the requirements of the instructions for use (IFU), the freedom from reintervention at 12 months was 98% compared with 86% when the implant was outside the IFU (p=0.009). At 1 year, the estimates of freedom from aortic-related and all-cause mortality were 98% and 95%, respectively.

CONCLUSION

The EVAS FORWARD Global Registry documents the 12-month outcome of EVAS in an unselected group of patients with challenging aortic morphology. The results at present appear acceptable with regard to perioperative outcomes and complications. The type II endoleak rate is low. The place of EVAS in the armamentarium of techniques to treat AAAs will be defined by durability data in the longer term.

Diagnosis of Abdominal Aortic Prosthesis Infection With FDG-PET/CT

A 79-year-old man was referred with recurrent periods of fever and chills. Six years earlier an aortic bifurcation graft had been implanted. Blood examination showed elevated infection parameters. A regular computed tomographic (CT) scan in the previous hospital showed no signs of graft infection. When blood cultures revealed multiple enteric bacteria, a 2-deoxy-2-[F18]fluoro- d-glucose-positron emission tomographic/CT (FDG- PET/CT) scan was performed that demonstrated ring-shaped pathological uptake at the proximal anastomosis. The patient was operated on and an infected graft was found, with a 1-cm defect in the distal part of the duodenum. Bacterial cultures of the explanted graft were positive. The patient recovered well from surgery and is on a regimen of prolonged antibiotic and antimycotic treatment.

One-Year Outcomes of Endovascular Aneurysm Repair in High-Risk Patients Using the Endurant Stent-Graft

Purpose: To evaluate the outcome and survival of patients with extensive comorbid conditions after endovascular aneurysm repair (EVAR) and objectify which of 2 medical comorbidity classifications is more accurate in predicting adverse outcomes. Methods: All 1263 patients (mean age 73.1 years; 1129 men) treated using the Endurant Stent Graft system and entered in the prospective global postmarketing ENGAGE registry ( ClinicalTrials.gov identifier NCT00870051) were grouped using the American Society of Anesthesiologists (ASA) classification and the Society for Vascular Surgery/American Association for Vascular Surgery (SVS/AAVS) medical comorbidity grading system. Patients assigned to ASA III and IV and SVS/AAVS 2 and 3 categories were considered high risk. Primary outcome was 1-year all-cause mortality. Secondary outcomes included technical and clinical success, major adverse events (MAE), aneurysm rupture, endoleaks, and secondary endovascular procedures. One-year follow-up of the entire ENGAGE cohort was the endpoint of the study. Results: A total of 1263 patients were included. The overall technical success rate was high, the lowest being 97.4% in the ASA I group. The overall 30-day and 1-year Kaplan-Meier survival estimates were 98.7% and 92.5%, respectively. All cause 1-year mortality was higher in the ASA III and IV groups, but this did not reach statistical significance (5.2% and 5.7% for ASA I and II vs 9.0% and 9.9% for ASA III and IV, p=0.12). In the SVS/AAVS groups, 1-year all-cause mortality significantly increased with the SVS/AAVS score to 11.3% in the SVS/AAVS 3 group (p=0.002). There were significantly more MAEs in the SVS/AAVS 3 group at 1 year (p<0.001 for group 1 vs 3 and group 2 vs 3). Conclusion: Endovascular aneurysm repair has evolved, and high technical success and low mortality and morbidity can be achieved in high-risk patients. When treating high-risk patients, the perioperative risks should always be weighed against the expected gains. In contrast to the ASA classification, the SVS/AAVS medical comorbidity grading system is a useful tool to predict occurrence of MAEs and 1-year survival in patients undergoing EVAR.

A comparative study of vascular injection fluids in fresh-frozen and embalmed human cadaver forearms

Over the years, various vascular injection products have been developed to facilitate anatomical dissections. This study aimed to compare the most commonly used vascular injection products in fresh-frozen and formalin-embalmed cadaver specimens. An overview of the properties, advantages and limitations of each substance was given, and a comparison of vascular infusion procedures in both preservation methods was made. A literature search was performed in order to identify the most commonly used vascular injection products. Acrylic paint, latex, gelatin, silicone, Araldite F and Batson's No. 17 were selected for the study. One fresh-frozen and one embalmed cadaver forearm were infused with each injection product according to a uniform protocol. The curing time, skin- and subcutaneous tissue penetration, degree of filling of the arterial tree, extravasations, consistency of the injected vessels during dissection, and the costs of each injection fluid were noted. There was a large variation between the injection fluids in processing- and curing time, colour intensity, flexibility, fragility, elasticity, strength, toxicity and costs. All fluids were suitable for infusion. The penetration of injection fluid into the skin and subcutaneous tissue was significantly better in fresh-frozen specimens (P = 0.002 and P = 0.009, respectively), with significantly smaller branches casted (P = 0.004). Vascular infusion of fresh-frozen cadaver specimens results in a significantly better filled coloured arterial tree, enabling more detail to be achieved and smaller branches casted. The biomechanical properties of fresh-frozen soft tissues are less affected compared with formalin fixation. All the injection fluids studied are suitable for vascular infusion, but their different properties ensure that certain products and procedures are more suitable for specific study purposes.

Treatment of Aortoiliac Occlusive Disease with the Endologix AFX Unibody Endograft

OBJECTIVE/BACKGROUND

Aorto-bifemoral bypass remains the gold standard for treatment of aortoiliac occlusive disease (AIOD) in patients with advanced (TASC D) lesions, but has significant associated morbidity and mortality. Treatment with a unibody stent-graft positioned at the aortic bifurcation is a potential endovascular option for the treatment of AIOD. The current study examines the safety, efficacy, and early patency rates of the Endologix AFX unibody stent-graft for treatment of AIOD.

METHODS

A multicenter retrospective review was conducted of patients treated exclusively for AIOD with the AFX device. Primary, assisted primary, and secondary patency rates were noted. Clinical improvement was assessed using Rutherford classification and ankle brachial index. Mean duration of follow-up was 22.2 ± 11.2 months. Ninety-one patients (56 males [62%]) were studied.

RESULTS

Sixty-seven patients (74%) presented with lifestyle-limiting intermittent claudication and the remaining 24 (26%) had critical limb ischemia. Technical success was 100%. Complications included groin infection (n = 4 [4%]), groin hematoma (n = 4 [4%]), common iliac rupture (n = 4 [4%]), iliac dissection (n = 4 [4%]), and thromboembolic event (n = 3 [3%]; one femoral, one internal iliac artery, and one internal iliac with bilateral popliteal/tibial thromboemboli). Thirty-day mortality was 1% (1/91) resulting from a case of extensive pelvic thromboembolism. At 1 year, 73% of patients experienced improvement in Rutherford stage of -3 or greater compared with baseline. Nine patients (10%) required 16 secondary interventions. At all time points, primary patency rates were > 90%, assisted patency rates were > 98%, and secondary patency rates were 100%.

CONCLUSION

This is the largest study to examine the use of the Endologix AFX unibody stent-graft for the treatment of AIOD. Use of the AFX stent-graft appears to be a safe and effective endovascular treatment for complex AIOD.

The Use of Heparin during Endovascular Peripheral Arterial Interventions: A Synopsis

A large variety exists for many aspects of the use of heparin as periprocedural prophylactic antithrombotics (PPAT) during peripheral arterial interventions (PAI). This variation is present, not only within countries, but also between them. Due to a lack of (robust) data, no systematic review on the use of heparin during PAI could be justified. A synopsis of all available literature on heparin during PAI describes that heparin is used on technical equipment to reduce the thrombogenicity and in the flushing solution with saline. Heparin could have a cumulative anticoagulant effect when used in combination with ionic contrast medium. No level-1 evidence exists on the use of heparin. A measurement of actual anticoagulation status by means of an activated clotting time should be mandatory.