Long-term Results of Angulated Versus Hyperangulated Neck in Endovascular Aneurysm Repair With Endurant Endoprosthesis.

PURPOSE: Patients with a hyperangulated (>60°) proximal aortic neck and at high risk of open surgery have been treated with endovascular aortic repair (EVAR). However, long-term outcomes are not well reported. The aim of this study is to compare the technical and clinical success of EVAR in angulated (45°-60°) and hyperangulated (>60°) proximal neck angulation. MATERIALS AND METHODS: The data of all consecutive patients undergoing EVAR treated between November 2007 and February 2020 were collected. A retrospective analysis of this prospective database was performed. The primary measure outcome was technical and clinical success. In addition, we evaluated sack evolution, type IA endoleak, secondary procedures, aneurysm rupture, mortality, aneurysm-related mortality, and migration. RESULTS: In all, 246 of 1353 EVAR patients presented with an angulation of the proximal neck >45°, 130 patients presented with an infrarenal angulation >60°, while 116 patients had an angulation between 45° and 60°. Patients with a hyperangulated infrarenal aortic neck were significantly more often women (8.6% vs 26.9%), older (73.9 vs 76.7 years), and had less often diabetes mellitus (20.7% vs 10.8%). Suprarenal neck angulation and reversed tapered neck were significantly more frequent in the hyperangulated group so that propensity scores were generated using these anatomical parameters to create a matched cohort group. No significant differences in technical (87.9% vs 94.8%) and clinical success (66.4% vs 69.8%) were observed. After a mean clinical follow-up of 58.9 months significantly more secondary procedures were performed in the hyperangulated group (23.3% vs 12.9% p=0.04); however, neck-related secondary procedures were comparable (1.7% vs 6.0%; p=0.09). Also, all-cause and aneurysm-related mortality, sack evolution, type IA endoleak, aneurysm rupture, and migration were comparable for both groups. CONCLUSION: Compared with less angulated proximal aortic neck, hyperangulated neck anatomy did not reduce the technical and clinical success of EVAR but increased the risk of secondary procedures. In patients who are not good candidates for open surgery, EVAR is a reasonable alternative.

Sex Differences in Endovascular Treatment of Isolated Popliteal Lesions.

PURPOSE: Sex-based differences in peripheral arterial disease are well-known. Aim of this study was to evaluate sex-related disparities in patients undergoing endovascular treatment of isolated popliteal artery lesions. MATERIAL AND METHODS: Between 1th January 2004 and 1th January 2021 304 patients underwent endovascular treatment of an isolated popliteal artery lesion at three vascular centers. A retrospective analysis was performed comparing the outcomes in female versus male patients. RESULTS: The majority of the patients were female (51.3%). Male patients were younger (70.4 vs. 76.8 years, p < 0.01). Hyperlipidemia (62.2% vs. 45.5%, p < 0.01) and diabetes (62% vs. 40%, p < 0.01) were more common in male group. There were more current and former smokers in the male group (p = 0.04 and p = 0.01). There were no differences regarding lesion length (mean 94.5 mm) nor location of the lesion. Technical success was comparable in both groups 94.6% vs. 97.4%), no differences in terms of in-hospital complications (9.5% vs. 7.7%) were found. At 3 years estimates did not demonstrate any difference in terms of clinically driven target lesion revascularization (23% vs. 34%), secondary patency (86% vs. 96%), and all-cause mortality (77% vs. 67%) between the two groups. CONCLUSION: In our experience the female sex showed clinical signs of popliteal artery lesion at higher age with less aggressive atherosclerotic risk factors. However, during the follow-up no sex-related significant differences were found in terms of morphological and clinical outcomes after endovascular revascularization.

A meta-analysis of safety and efficacy of endovascular aneurysm repair in aneurysm patients with severe angulated infrarenal neck.

OBJECTIVES: A growing number of abdominal aortic aneurysms with severe angulated neck anatomy is treated by endovascular means. However, contradictory early and late outcomes have been reported. Our review and outcome analysis attempted to evaluate the available literature and provide clinicians with a base for clinical implementation and future research. MATERIALS AND METHODS: A systematic review of the literature was undertaken to identify the outcomes of endovascular aneurysm repair in patients with severe infrarenal neck angulation (SNA ≥ 60°) vs non-severe neck angulation (NSNA). Outcome measures included perioperative complications, type 1a endoleak, neck-related secondary procedures, stent graft migration, aneurysm rupture, increase (>5mm) in sac diameter, all-cause and aneurysm-related mortality (PROSPERO Nr.: CRD42021233253). RESULTS: Six observational studies reporting on 5981 patients (1457 with SNA and 4524 with NSNA) with a weighted mean follow-up period of 1.8 years were included. EVAR in SNA compared with NSNA was associated with a higher rate of type 1a endoleak at 30 days (4.0% vs 1.8%; p< 0.00001), at 1 year (2.8% vs 1.9%; p<0.03), at 2 years (4.9% vs 2.1%; p< 0.0002), at 3 years (5.6% vs 2.6%; p< 0.0001). The rate of neck-related secondary procedures was significantly higher at 1 year (6.6% vs 3.9%; p<0.05) and at 3 years (13.1% vs 9%; p<0.05). Graft migration, aneurysm sack increase, aneurysm rupture and all-cause mortality were not statistically different at mid-term. CONCLUSIONS: The use of EVAR in severely angulated infrarenal aortic necks is associated with a high rate of early and mid-term complications. However, aortic related and all-causes mortality are not higher compared to patients with NSNA. Therefore, EVAR should be cautiously used in patients with SNA.

Use of Chimney Technique Does Not Improve the Outcome of Endovascular Aneurysm Repair in Patients With a Hyperangulated and Short Proximal Aortic Neck.

PURPOSE: We hypothesized that extending the proximal landing zone with the chimney technique could be beneficial in patients with a hyperangulated proximal aortic neck, defined as more > 60 degrees. MATERIAL AND METHODS: We retrospectively analyzed the outcome of prospectively collected data of patients treated by endovascular aneurysm repair (EVAR) for infrarenal aortic aneurysm with a hyperangulated proximal aortic neck. In all, 104 out of 130 patients were treated without (Group A) and 24 with the chimney endovascular aortic repair (ChEVAR, Group B). Primary outcome was technical and clinical success according to the reporting standards of the Society of Vascular Surgery. RESULTS: The use of the chimney technique was associated with a significantly longer operation duration (167 vs. 93 min, p < .001), longer fluoroscopy time (44 vs.30 min, p = < .001), and larger amount of contrast medium used (149 vs. 127 ml, p = .03) but did not significantly improve technical (79.2% vs. 87.7%) and clinical success (54.2% vs. 68.9%). Aneurysm-related mortality was higher in group B (8.3% vs. = 0%, p < .001). Type IA endoleak was high in both groups at completion angiography (11.3% in Group A vs. 12.5% in Group B) and at follow-up (10.4% in Group A vs. 4.5% in Group B) without significant difference between the groups. CONCLUSIONS: Our data did not show a benefit of the primary use of the chimney technique in patients with a hyperangulated and short neck, although more studies are required to support this conclusion. Other strategies or new technologies are required for improving EVAR results in aneurysm patients with severe angulated proximal and short neck.

Performance of the Gore VBX Balloon Expandable Endoprosthesis as Bridging Stent-Graft in Branched Endovascular Aortic Repair for Thoracoabdominal Aneurysms.

PURPOSE: Bridging stent stability is crucial for efficacy and safety of branched aortic endovascular repair (bEVAR) of thoracoabdominal aortic aneurysms (TAAAs). In this study, we assess the performance of the new Viabahn Balloon-Expandable endoprosthesis (VBX) in bEVAR. Based on our learning curve we give recommendations for a safe and effective use of the device. MATERIALS AND METHODS: We prospectively collected the data of patients with TAAAs undergoing bEVAR between December 2017 and December 2019. All patients with implantation of at least 1 VBX stent-graft as bridging stent were included in our single-center analysis. Demographic, comorbidity, and computed tomography angiography (CTA) data of 112 patients were retrospectively evaluated. Primary endpoint was a composite of branch-related technical success and freedom from target vessel instability. Secondary endpoints were clinical and ongoing clinical success. RESULTS: Primary endpoint: technical success was achieved in all patients (100%) with a freedom from target vessel instability of 96.3% after a median follow-up of 18 months. Overall mortality was 13.4% (n=15) and 13 patients underwent secondary interventions, 12 of them are still alive and 1 suffered from aneurysm sac expansion, consequently an ongoing clinical success of 75.9% was reached. After modification of the implantation technique during the course of the study by selecting longer stent lengths after accurate estimation of vessel curvature and expected adaptation of the flexible endoskeleton to the specific anatomical conditions, no type Ic endoleaks were observed in the last 70 cases. CONCLUSIONS: The VBX stent-graft can be safely used as bridging stent for branched thoracoabdominal repair. However, learning curve should be considered to avoid type Ic endoleak and edge stenosis. Based on this experience longer landing zones and 2-step deployment of VBX are useful for successful bridging also of challenging target vessels.

Fatigue Resistance of the Advanta V12/iCast and Viabahn Balloon-Expandable Stent-Graft as Bridging Stents in Experimental Fenestrated Endografting.

PURPOSE: Bridging stents undergo millions of cycles during respiratory movements of the kidneys throughout the patient's life. Thus, understanding the response of fabric and endoskeleton of the stent to cyclic loading over the time is crucial. In this study, we compare the fatigue resistance of the Viabahn Balloon-Expandable stent-graft (VBX) with the widely used Advanta V12/iCast under prolonged stress induction. MATERIALS AND METHODS: A polyester test sheet with 10 fenestrations was used simulating a fenestrated endograft. Five 6×59 mm VBX stent-grafts and five 6×58 mm Advanta stent-grafts were implanted into 6×6 mm fenestrations. The stents were flared with a 10×20 mm PTA (percutaneous transluminal angioplasty) catheter and connected with a fatigue stress machine. All stent-grafts were evaluated by microscopy and radiography at baseline and after regular intervals until 50,000,000 cycles were applied, simulating a life span of approximately 75 months. Freedom from fracture (FF), freedom from initial polytertafluoroethylene (PTFE) changes (FIC), and from PTFE breakpoint (FBP, all-layer defect) were calculated. RESULTS: Digital radiographic images did not show any stent fracture in both groups after 50,000,000 cycles. The VBX stent-graft was free from any all-layer defects at the conclusion of 50,000,00 cycles resulting in a significant higher FBP compared with Advanta V12 (50,000,000 vs 33,400,000; p<0.01). All-layer defects were observed only in the Advanta group. Two of 5 Advanta stents showed early penetration of the nitinol ring causing a defect of PTFE. Regarding FIC, there was no significant difference between the stents (3,400,000 in VBX vs 3,200,000 in Advanta). CONCLUSIONS: In fatigue tests simulating respiration movements, VBX and Advanta V12 performed equally well in terms of fracture resistance and freedom from initial PTFE changes. VBX maintained freedom from PTFE breakpoint throughout the full 50,000,000 cycles. All-layers defects were detected only in Advanta and were mainly caused by penetration of the nitinol ring through the PTFE.

Role of protein histidine phosphatase for viability of neuronal cells.

We recently found protein histidine phosphatase (PHP) in eukaryotes and identified ATP-citrate lyase (ACL) and the beta-subunit of G-proteins as its substrates. The aim of the present study was to get information on the significance of PHP for cellular function and viability. PHP was overexpressed by a viral vector in SH-SY5Y cells, a human neuroblastoma cell line, and in primary cultures of cortical neurons from embryonic (E19) rats. Furthermore, PHP was downregulated by siRNA in SH-SY5Y cells. We could demonstrate that overexpression of PHP decreased the phosphorylation state of ACL. Accordingly, the activity of ACL seemed to be reduced and subsequently, the viability of the cells was diminished. On the other hand, downregulation of PHP did not clearly influence phosphorylation and activity of ACL as well as viability of the cells. The results suggest that an increased activity of PHP impairs cellular function whereas downregulation of PHP does not.

Reduced viability of neuronal cells after overexpression of protein histidine phosphatase.

Protein histidine phosphatase (PHP) has just recently been discovered in eukaryotes and ATP-citrate lyase (ACL) was shown to be one of its substrates. Since ACL is crucial for cellular energy and fat metabolism we made an attempt to study the influence of PHP on cell viability. Using an adenoviral vector PHP was overexpressed in SN56 cholinergic murine neuroblastoma cells and in primary cultures of hippocampal neurons obtained from embryonic rats (E18). Overexpression of PHP in these cells caused a decrease in ACL activity and consequently impaired viability. To be sure that the reduced cellular viability was achieved by overexpression of PHP we also downregulated ACL in SN56 cells using RNAi-technology. Downregulation of ACL was harmful to the cells similar to what was observed upon overexpression of PHP. Taken together, it is concluded that overexpression of PHP results in increased dephosphorylation with concomitant inactivation of ACL, thus finally leading to cell damage.