Retrospective Cohort Study on Vessel Deformation During Fenestrated or Branched Endovascular Aortic Repair; Traditional CTA Roadmaps Provide Insufficient and Inadequate Guidance During Target Vessel Cannulation

Introduction: Optimal visualization of target vessels in three-dimensions (3D) plays a key role in complex endovascular procedures, such as fenestrated and branched endovascular aortic repair (EVAR). A popular imaging technique to enhance target vessel visualization is image fusion. Image fusion combines real-time fluoroscopy with static preprocedural anatomical images, typically computed tomography angiography (CTA) to create an arterial roadmap. However, the introduction of stiff endovascular devices cause the arteries to stretch, leading to a mismatch between the actual position of the (origin of the) artery and its representation on the image fusion roadmap. This retrospective study assesses vessel deformation of the aorta and its side branches due to the introduction of a stiff endovascular devices, during fenestrated and branched EVAR. Furthermore, the influence of vascular tortuosity on the extent of vessel deformation was analysed. Methods: Patients that underwent fenestrated or branched EVAR between January 2015 and January 2018 were retrospectively included in this study. Two imaging datasets were collected from each patient: 1) the preoperative CTA and 2) the intraoperative contrast-enhanced cone beam computed tomography (ce-CBCT), acquired after the insertion of the stiff guidewire and stent delivery device (Zenith custom made, Cook, Bloomington IN, USA) . Manual registration of both datasets was performed, using the bony landmarks of the vertebrae. Subsequently, the ostium of the celiac artery (CA), superior mesenteric artery (SMA), left renal artery (LRA) and right renal artery (RRA) were marked in both the CTA and ce-CBCTreconstructions.The ostium displacement of the four target vessels was reported as a 3D vector as well as a 2D vector in the coronal plane (RRA and LRA) or sagittal plane (CA and SMA). The tortuosity index of the iliac and the abdominal aortic segment were calculated. The effect of the tortuosity index on the extent of vessel deformation was assessed using linear regression. Results: In total 77 target vessels from 20 patients were included in this study. The 3D mean displacement vector of the ostium of the CA, SMA, RRA and LRA were respectively 8.73.8mm, 7.42.7mm, 7.92.7mm and 7.64.4mm. The 2D mean displacement vector for the SMA and CA in the sagittal viewing plane was 4.92.9mm and 6.53.0mm respectively. The 2D mean displacement vector of the RRA and LRA in the coronal viewing plane was 7.02.8mm 6.24.3mm respectively. An example of the 2D displacement of the RRA in the coronal plane is shown in Figure 1. In total, 74% of the target vessels had a 2D vector displacement of more than 50% of the diameter of the vessel. The mean tortuosity index of the abdominal aortic segment and the iliac segment was 1.10 and 1.34 respectively. Linear regression showed no association between the extend of vessel displacement and the tortuosity index of the abdominal aortic segment (p¼0.37), nor the iliac segment (p¼0.11). Conclusion: There is significant vessel displacement of the ostium of the target vessels, during fenestrated and branched EVARs caused by the introduction of stiff endovascular devices. Consequently, preoperative CTA roadmaps are inadequate to guide target vessel cannulation during fenestrated or branched EVAR

Heterogeneity in Standard Operating Procedures for Catheter Directed Thrombolysis for Peripheral Arterial Occlusions in The Netherlands : A Nationwide Overview

Objective: Catheter directed thrombolysis (CDT) for acute arterial occlusions of the lower extremities is associated with a risk of major bleeding complications. Strict monitoring of vital functions is advised for timely adjustment or discontinuation of thrombolytic treatment. Nevertheless, current evidence on the optimal application of CDT and use of monitoring during CDT is limited. In this study the different standard operating procedures (SOPs) for CDT in Dutch hospitals were compared against a national guideline in a nationwide analysis. Methods: SOPs, landmark studies, and national and international guidelines for CDT for acute lower extremity arterial occlusions were compared. The protocols of 34 Dutch medical centres where CDT is performed were assessed. Parameters included contraindications to CDT, co-administration of heparin, thrombolytic agent administration, angiographic control, and patient monitoring. Results: Thirty-four SOPs were included, covering 94% of medical centres performing CDT in the Netherlands. None of the SOPs had identical contraindications and a strong divergence in relative and absolute grading was found. Heparin and urokinase dosages differed by a factor of five. In 18% of the SOPs heparin co-administration was not mentioned. Angiographic control varied between once every 6 h to once every 24 h. In 76% of the SOPs plasma fibrinogen levels were used for CDT dose adjustments. However, plasma fibrinogen level threshold values for treatment adjustments varied between 2.0 g/L and 0.5 g/L. Conclusion: The SOPs for CDT for acute arterial occlusions of the lower extremities differ greatly on five major operating aspects among medical centres in the Netherlands. None of the SOPs exactly conforms to current national or international guidelines. This study provides direction on how to increase homogeneity in guideline recommendations and to improve guideline adherence in CDT

Surgical Treatment of Acute Thoracic Stent Graft Occlusion

A 24-year-old man presented with acute onset paraplegia related to complete occlusion of a thoracic stent graft placed 2 years prior for repair of traumatic type B aortic dissection. Following emergency surgery comprising reestablishment of aortic flow by stent removal and aortic reconstruction, the paraplegia started to resolve partly, despite an estimated 5-hour interval of preoperative myelum ischemia. Anatomical characteristics of the stent graft placement appear to have played a role in causing this rare complication. Six months later, the patient could walk again with a stick. This case shows that early intervention in cases of full paraplegia may be considered

Target vessel displacement during fenestrated and branched endovascular aortic repair and its implications for the role of traditional computed tomography angiography roadmaps

Background: This retrospective study quantifies target vessel displacement during fenestrated and branched endovascular aneurysm repair due to the introduction of stiff guidewires and stent graft delivery systems. The effect that intraoperative vessel displacement has on the usability of computed tomography angiography (CTA) roadmaps is also addressed. Methods: Patients that underwent fenestrated or branched EVAR were included in this retrospective study. Two imaging datasets were collected from each patient: (I) preoperative CTA and (II) intraoperative contrastenhanced cone beam computed tomography (ceCBCT) acquired after the insertion of the stiff guidewire and stent graft delivery system. After image registration, the 3D coordinates of the ostium of the celiac artery, superior mesenteric artery, right renal artery and left renal artery were recorded in both the CTA and the ceCBCT dataset by two observers. The three-dimensional displacement of the ostia of the target vessels was calculated by subtracting the coordinates of CTA and ceCBCT from one another. Additionally, the tortuosity index and the maximum angulation of the aorta were calculated. Results: In total 20 patients and 77 target vessels were included in this study. The ostium of the celiac, superior mesenteric, right renal and left renal artery underwent non-uniform three-dimensional displacement with mean absolute displacement of 8.2, 7.7, 8.2 and 6.2 mm, respectively. The average displacement of all different target vessels together was 7.8 mm. A moderate correlation between vessel displacement and the maximum angulation of the aortoiliac segment was found (Spearman's ρ=0.45, P<0.05). Conclusions: The introduction of stiff endovascular devices during fenestrated or branched EVAR causes significant, non-uniform displacement of the ostium of the visceral and renal target vessels. Consequently, preoperative CTA roadmaps based on bone registration are suboptimal to guide target vessel catheterization during these procedures

Midterm outcomes and evolution of gutter area after endovascular aneurysm repair with the chimney graft procedure

Objective: The objective of this study was to describe our experience with endovascular aneurysm repair (EVAR) with the use of chimney grafts for branch vessel preservation. Methods: Patients treated with a chimney graft procedure between October 2009 and May 2015 were included for analysis. Patients who were not considered eligible for open surgical repair or for conventional, branched, or fenestrated endovascular repair were selected. A standardized operating procedure with left brachial or axillary artery cutdown access for the chimney grafts and bilateral femoral artery cutdown access for the aortic main device was used. Outcomes were noted according to the Society for Vascular Surgery reporting standards. In addition, evolution of gutter area over time was determined. Estimated rates of survival, freedom from aneurysm growth, and clinical success at 24 months of follow-up were calculated. Results: Thirty-three patients (mean age, 77.6 ± 6.8 years; 87.9% male) with a mean preoperative maximum aneurysm diameter of 71.7 ± 13.5 mm were included. A total of 54 of an intended 54 chimney grafts were deployed. Primary technical success and 30-day secondary clinical success rates were 87.9% and 84.8%, respectively. The early mortality rate was 6.1% (n = 2). The early type Ia endoleak rate was 6.1% (n = 2), and the chimney graft occlusion rate was 6.1% (n = 2). Median follow-up duration was 26 months (interquartile range, 14.8-37.3 months). The estimated 2-year actuarial survival rate was 78.1% (standard error, ±7.4%). Late complications included type Ia endoleak (n = 1), chimney graft occlusion (n = 2), type II endoleak with aneurysm growth (n = 4), and distal stent graft limb kinking and occlusion (n = 1). Late reinterventions included coil or glue embolization (n = 3), distal limb extension (n = 2), open endoleak ligation (n = 2), Palmaz stent placement (n = 1), repeated EVAR (n = 1), and femorofemoral bypass graft (n = 1). At 2 years, the estimated secondary clinical success and freedom from aneurysm growth rates were 80.5% (±7.2%) and 84.4% (±7.2%). Gutter size showed a small but significant decrease over time at the level of the proximal markers and at 10 mm distal from the markers. Conclusions: Midterm results show that a standardized procedure for EVAR using chimney grafts for branch vessel preservation is an acceptable option for high-risk patients with large, complex aneurysms who are unfit for open repair and who have been excluded from fenestrated EVAR. Gutter size decreases over time, but the rate of branch vessel loss and reinterventions demonstrate that this approach should remain reserved for those who are at truly prohibitive risk for open or fenestrated stent graft repair

Association of Hospital Volume with Perioperative Mortality of Endovascular Repair of Complex Aortic Aneurysms:A Nationwide Cohort Study

OBJECTIVE: We evaluate nationwide perioperative outcomes of complex EVAR and assess the volume-outcome association of complex EVAR. SUMMARY OF BACKGROUND DATA: Endovascular treatment with fenestrated (FEVAR) or branched (BEVAR) endografts is progressively used for excluding complex aortic aneurysms (complex AAs). It is unclear if a volume-outcome association exists in endovascular treatment of complex AAs (complex EVAR). METHODS: All patients prospectively registered in the Dutch Surgical Aneurysm Audit who underwent complex EVAR (FEVAR or BEVAR) between January 2016 and January 2020 were included. The effect of annual hospital volume on perioperative mortality was examined using multivariable logistic regression analyses. Patients were stratified into quartiles based on annual hospital volume to determine hospital volume categories. RESULTS: We included 694 patients (539 FEVAR patients, 155 BEVAR patients). Perioperative mortality following FEVAR was 4.5% and 5.2% following BEVAR. Postoperative complication rates were 30.1% and 48.7%, respectively. The first quartile hospitals performed <9 procedures/yr; second, third, and fourth quartile hospitals performed 9-12, 13-22, and ≥23 procedures/yr. The highest volume hospitals treated the significantly more complex patients. Perioperative mortality of complex EVAR was 9.1% in hospitals with a volume of < 9, and 2.5% in hospitals with a volume of ≥13 (P = 0.008). After adjustment for confounders, an annual volume of ≥13 was associated with less perioperative mortality compared to hospitals with a volume of < 9. CONCLUSIONS: Data from this nationwide mandatory quality registry shows a significant effect of hospital volume on perioperative mortality following complex EVAR, with high volume complex EVAR centers demonstrating lower mortality rates

Association of Hospital Volume with Perioperative Mortality of Endovascular Repair of Complex Aortic Aneurysms: A Nationwide Cohort Study

Objective : We evaluate nationwide perioperative outcomes of complex EVAR and assess the volume-outcome association of complex EVAR. Summary of Background Data: Endovascular treatment with fenestrated (FEVAR) or branched (BEVAR) endografts is progressively used for excluding complex aortic aneurysms (complex AAs). It is unclear if a volumeoutcome association exists in endovascular treatment of complex AAs (complex EVAR). Methods : All patients prospectively registered in the Dutch Surgical Aneurysm Audit who underwent complex EVAR (FEVAR or BEVAR) between January 2016 and January 2020 were included. The effect of annual hospital volume on perioperative mortality was examined using multivariable logistic regression analyses. Patients were stratified into quartiles based on annual hospital volume to determine hospital volume categories. Results : We included 694 patients (539 FEVAR patients, 155 BEVAR patients). Perioperative mortality following FEVAR was 4.5% and 5.2% following BEVAR. Postoperative complication rates were 30.1% and 48.7%, respectively. The first quartile hospitals performed <9 procedures/ yr; second, third, and fourth quartile hospitals performed 9-12, 13-22, and ≥23 procedures/yr. The highest volume hospitals treated significantly more complex patients. Perioperative mortality of complex EVAR was 9.1% in hospitals with a volume of <9, and 2.5% in hospitals with a volume of ≥13 (P = 0.008). After adjustment for confounders, an annual volume of 13 was associated with less perioperative mortality compared to hospitals with a volume of <9. Conclusions : Data from this nationwide mandatory quality registry shows a significant effect of hospital volume on perioperative mortality following complex EVAR, with high volume complex EVAR centers demonstrating lower mortality rates