Safety, Effectiveness and Pitfalls of Carbon Dioxide Routine Use as a Contrast Agent for Endovascular Abdominal Aortic Repair.

BACKGROUND: Despite the evidence of good performance, carbon dioxide (CO2) routine employment as a contrast agent for endovascular procedures is far from being adopted with its use currently limited to patients with renal impairment and known allergy to iodinated contrast medium (ICM). The purpose of our study is to evaluate the safety and effectiveness of CO2 guided endovascular abdominal aortic aneurysm repair (EVAR) in a standard population and to assess the rationale for a future widespread use. METHODS: We retrospectively collected data of every patient who underwent CO2 guided standard EVAR from September 2020 to May 2021 and compared them with the data of every patient who underwent EVAR using ICM from December 2019 to August 2020 in our unit. The selection of the contrast medium was not based on any preoperative factor as the contrast medium was routinely used in every patient in both periods. The primary end point of the study was the technical success rate. Secondary end points were the early and late complication rates, radiation exposure and renal function impairment. RESULTS: 49 patients underwent ICM guided EVAR and 52 patients underwent CO2 guided EVAR in our unit in the time frames specified above. The technical success rate was 100% in both groups with no accidental coverage of any target vessel. Intraoperative endoleaks were observed in 14% of ICM patients and 25% of CO2 patients. The radiation exposure was higher in the CO2 group if compared to the ICM group (311.48 vs. 159.86 median mGy/cm2 - P < 0.001). The incidence of postoperative acute kidney injury was low and similar in the 2 groups. No significant worsening over time of the renal function has been reported in both groups. CONCLUSIONS: EVAR can be safely performed under CO2 guidance without the integration of any quantity of ICM but with an increase in radiation exposure. The nephroprotective role of CO2 guided EVAR in a standard population is unclear and the same role in renal impaired patients should be validated with further studies on selected populations.

Monoplane versus biplane fluoroscopy in patients undergoing fenestrated/branched endovascular aortic repair.

OBJECTIVE: Endovascular aortic repair (EVAR) with fenestrated (F-EVAR) or branched (B-EVAR) endografts represents an indispensable tool of modern patient care in vascular surgery. The purpose of this retrospective study was to evaluate the center's initial experience of F/B-EVAR procedures performed under biplane angiography guidance compared with a historical control group. METHODS: From January 2020 to March 2022, 80 consecutive patients underwent F/B-EVAR under general anesthesia at a single institution. As from January 2021, the deployment of complex stent grafts was performed using an alternative intraoperative imaging modality-a biplane fluoroscopy and angiography. The cohort was divided into monoplane (MPA) and biplane (BPA) groups according to the imaging modality applied. The end points were operation time, fluoroscopy time, radiation exposure, dose of contrast agent, and technical success. RESULTS: The MPA group included 59 patients (78% male; median age; 74 years; interquartile range [IQR], 66-78 years) and the BPA group 21 patients (85.7% males; median age, 75 years; IQR, 69-79 years). Operation time (median, 320 minutes; IQR, 266-376 minutes) versus (median, 275 minutes; IQR, 216-333 minutes) was significantly lower in the BPA group (P = .006). The median fluoroscopy time (median, 82 minutes; IQR, 57-110 minutes vs median, 68 minutes; IQR, 54-92 minutes), contrast agent volume applied (median, 220 mL; IQR, 179-250 mL vs median, 200 mL; IQR, 170-250 mL), and radiation dose (dose-area product, median, 413 Gy × cm2; IQR, 249-736 Gy × cm2; vs median, 542 Gy × cm2; IQR, 196-789 Gy × cm2) were similar in both groups. Technical success of 96.6% (57/59 cases) versus 100% (21/21 cases) could be achieved in MPA and BPA group, respectively. CONCLUSIONS: F/B-EVAR procedures performed under BPA guidance were associated with a significant decrease in operation time.

Endovascular Treatment of Abdominal Aortic Aneurysm With Severe Angulation of Infrarenal Aortic Neck by Gore Conformable Endograft.

INTRODUCTION: The aim of the study is to report a single-center experience with the Gore Excluder conformable endograft with active control system (CEXC Device, W.L. Gore and Associates, Flagstaff, AZ, USA) in abdominal aortic aneurysms (AAAs) with severe infrarenal neck angulation. METHODS: All patients underwent EVAR with CEXC Device between September 2018 and 2020, were prospectively enrolled, and retrospectively analyzed. Anatomical details of the proximal aortic neck were evaluated. Early endpoints were the use of repositionability and angulation system, intraoperative unplanned cuff, technical success (TS), 30-day morbidity/mortality, and reintervention. Follow-up endpoints were type-I endoleaks, endograft migration, aortic neck dilatation, aneurismal sac shrinkage, survival (S), and freedom from reintervention (FFR). RESULTS: Twenty-five patients were enrolled (median age: 80 [range = 60-90] years, median AAA diameter: 60 [range = 52-90] mm). All patients had severe infrarenal neck angulation (beta angle ≧ 60°), and 11 (44%) of those had neck beta angle ≧ 90°. Median infrarenal neck angle, length, and diameter were 70° (range = 60°-90°), 22 (range = 13-42) mm and 22 (range = 18-31) mm, respectively. Endograft repositioning system was employed in 15 (60%) cases and the median number of repositioning maneuvers was 1 (range:0-4). Active angulation system was used in 17 (68%) patients. The median proximal diameter of the main-body and oversize were 28 (range = 23-36) mm and 28% (range = 21%-38%), respectively. Proximal cuff was positioned in 1 (4%) patient. Technical success was achieved in all cases. Intraoperative and perioperative morbidity and mortality were 12% and 0%, respectively. Perioperative type-I/III and II endoleaks were observed in 0 and 4 (16%) patients, respectively. The median follow-up was 12 months (range: 3-30). One patient died at 12-month for AAA-unrelated causes. Abdominal aortic aneurysm-sac shrinkage and stability were observed in 9 (36%) and 15 (60%) cases, respectively. No type-I/III endoleak and reintervention occurred during the follow-up. One persistent type-II endoleak was observed. Estimated survival at 24 months was 92%. CONCLUSION: According to the present data, the CEXC Device allows an excellent rate of TS in severe angulated aortic neck. This preliminary data, could increase the rate of patients eligible for EVAR.

Safety of Utilizing Ultrasound as the Sole Modality of Follow-Up after Endovascular Aneurysm Repair.

BACKGROUND: Post endovascular aneurysm repair (EVAR), surveillance with computed tomography-aortography (CTA) remains the most common practice, per Society for Vascular Surgery (SVS) guidelines. Chronic exposure to both radiation and intravenous (IV) contrast has raised concerns about long-term CTA follow-up (FU). As we have selectively used ultrasound (US) as a sole modality for post-EVAR surveillance, we sought to review our outcomes in this subset of patients. METHODS: Retrospective review of our institution's vascular database identified 213 EVAR patients from 2013 to 2021. Fenestrated-EVAR and snorkel reconstructions were excluded. Patient demographics/outcomes, abdominal aortic aneurysm (AAA) characteristics, and FU modalities and outcomes were analyzed. Unpaired Student's t-test, ANOVA, and chi-squared test were used to assess group differences. RESULTS: Eighty-five of the 213 EVAR patients (39.9%) were lost to FU within 3 months. Among the 128 remaining patients, 91 underwent FU using initial US, while 37 patients underwent post-EVAR FU initially using CTA. There were no significant differences (P > 0.05) between patient age (75.5 ± 9.4 vs. 75.3 ± 8.5), body mass index (BMI) (27.7 ± 5.4 vs. 28.9 ± 7.4), or mean AAA size (5.6 ± 1.1 vs. 5.9 ± 1.2) in US-surveilled and computed tomography (CT)-surveilled groups, respectively. Of the 91 patients, initially surveilled with US, 15 patients demonstrated endoleak and/or AAA growth (>5 mm). The 15 patients with US-demonstrated endoleak and/or growth underwent confirmatory CTA, with 3 patients eventually requiring EVAR revision. Among 37 patients initially surveilled with CT, 10 demonstrated significant growth and 2 patients eventually required EVAR revision. There were no patients with AAA rupture during post-EVAR surveillance. FU data were analyzed among a select lower-risk group of patients (preoperative AAA diameter ≤5.5 cm, BMI ≤30, and no endoleak at completion of EVAR). Among this group, there were no surveilled patients who required EVAR reintervention, regardless of surveillance modality (US n = 32; CT n = 4). The average FU was 29.5 ± 26.4 months in the US group and 26.4 ± 22.3 months in the CT group (P > 0.05). CONCLUSIONS: Although initial CT surveillance following EVAR remains ideal, in select lower-risk patients, US is a viable alternative even for the initial post-procedure study. Advantages include decreased radiation exposure and cost. Our data suggest that US is a safe sole modality for surveillance following EVAR in selective patients.

Prediction of Abdominal Aortic Aneurysm Growth After Endovascular Aortic Repair by Measuring Brachial-Ankle Pulse Wave Velocity.

BACKGROUND: Although endovascular aortic repair (EVAR) has become the dominant therapeutic approach for abdominal aortic aneurysm (AAA), continued sac growth after EVAR remains a major concern and is still unpredictable. Since AAA formation is thought to arise from atherosclerotic vascular damage of the aortic wall, we hypothesize that the severity of atherosclerosis in the AAA wall may influence sac growth. Therefore, we investigated whether brachial-ankle pulse wave velocity (baPWV), a marker of atherosclerosis severity obtained by noninvasive automatic devices, can predict sac growth after EVAR. METHODS: The data from all patients who underwent elective EVAR for AAA at a single institution from January 2012 to March 2019 were reviewed. We extracted the baPWV before EVAR and divided patients into 2 groups according to the baPWV cut-off value identified by a classification and regression tree (CART). The primary outcome was significant sac growth, defined as an increment of 5 mm or more in aneurysm size after EVAR relative to the aneurysm size before EVAR. Cox regression analysis was performed to assess the potential predictors of sac growth. RESULTS: During the follow-up period, 222 consecutive patients underwent elective EVAR for AAA. Of these, 175 patients with a median follow-up period of 36 months were included. The baPWV values were classified as <1854 cm/s (Group 0) in 100 patients and ≥1854 cm/s (Group 1) in 75 patients according to the cut-off value identified by CART. During the follow-up period, 10 (10.0%) patients in Group 0 and 18 (24.0%) patients in Group 1 demonstrated significant sac growth (P = 0.021). Risk factors for significant sac growth included baPWV (hazard ratio [HR], 3.059; 95% confidence interval [CI], 1.41-6.64; P = 0.005), age (HR, 1.078; 95% CI, 1.01-1.16; P = 0.036), and persistent type II endoleak (HR, 3.552; 95% CI, 1.69-7.48; P < 0.001). Multivariate analysis revealed that baPWV remained a significant risk factor for sac growth after adjustment for age (HR, 2.602; 95% CI, 1.15-5.82; P = 0.02) and persistent type II endoleak (HR, 2.957; 95% CI, 1.36-6.43; P = 0.006). CONCLUSIONS: The baPWV before EVAR was associated with significant sac growth after EVAR; thus, measuring the baPWV may be useful for assessing the risk of future sac growth in patients after EVAR.

Fully Ultrasound-Assisted Endovascular Aneurysm Repair: Preliminary Report.

BACKGROUND: Reducing fluoroscopy times and iodine contrast administration during endovascular repair (EVAR) of infrarenal aortic aneurysms remains a challenge. The purpose of this study is to evaluate the preliminary results of a fully ultrasound-assisted EVAR without iodine contrast administration. METHODS: Twenty-seven consecutive patients underwent an elective intravascular ultrasound (IVUS)-assisted EVAR with final contrast-enhanced ultrasound (CEUS) control of correct aneurysm exclusion. In no case intraprocedural injection of iodine contrast medium was performed. The primary study's end points were the overall duration of the procedure, duration of fluoroscopy, cumulative radiation dose, the length of intraoperative CEUS control, and the comparison of findings between intraoperative CEUS and computed tomography (CT) scan at 1 month. RESULTS: Mean duration of the procedure was 130 ± 35 min. Overall duration of fluoroscopy was 22 ± 18 min. Mean radiation dose was 66 mGy (range 24-82). The mean length of CEUS final control was 8 ± 2 min. No type I or type III endoleak was detected either at CEUS or at angio-CT scan at 1 month from EVAR. CEUS revealed a type II endoleak in 6 patients (22%), compared to 9 type II endoleaks (33%) detected at angio-CT scan 1 month after the procedure (P = 0.5). CONCLUSIONS: Fully ultrasound (IVUS and CEUS)-assisted EVAR is safe, feasible, and reliable, completely eliminating the need for iodine contrast medium and reducing the radiation exposure for both patients and surgeons.

Can we replace computed tomography angiography by contrast-enhanced ultrasound in the surveillance of patients submitted to aortoiliac aneurysm repair?

OBJECTIVES: This study was designed for evaluation of CEUS (contrast-enhanced ultrasound) for the detection of endoleaks after EVAR (endovascular aortic aneurysms repair) as an alternative to CTA (computed tomography angiography), the gold standard in post-EVAR surveillance. METHODS: Post-EVAR surveillance of patients who underwent CEUS and CTA was retrospectively analyzed to compare the accuracy of CEUS compared to CTA. For that, the following parameters were analyzed: the largest aneurysm diameter, type of endoleaks, and the time elapsed after EVAR using both surveillance tests. RESULTS: The study involved 110 pairs of exams in patients with infrarenal aortoiliac or isolated iliac artery aneurysm, covering predominantly a male population (89%). The time elapsed after EVAR using CEUS or CTA exams were statistically similar, ranging from one to 58 months (mean 12.2) and one to 65 months (mean 9.7), respectively (p = 0.124). CEUS sensitivity was 75.5%, specificity 96.7%, false positives were 24.5%, and false negatives were 3.3%. The accuracy between the two exams was 87.3%. A secondary analysis, comparing CTA with CEUS as a reference standard, revealed CEUS sensitivity of 24.5%, higher than CTA for detecting endoleaks, with a concordance rate of true positive results of 75.5%. Among the endoleaks detected solely by CEUS (12 cases), one case was type Ia and eleven were type II, while those detected only by CTA (2 cases), one was type Ia and one type II. Additionally, a type II endoleak associated with type Ib, identified by CEUS, was seen as type II for CTA only. There was no difference between the pre-EVAR and the post-EVAR diameters of aortoiliac aneurysm (p = 0.058), both for CEUS and CTA. Computed tomography angiography, on the other hand, showed significant aneurysm diameter reduction compared to CEUS for isolated iliac artery aneurysms (p < 0.001). CONCLUSION: Contrast-enhanced ultrasound was more effective than CTA in identifying and characterizing endoleaks in patients undergoing EVAR, especially type II endoleaks. The advantages include efficacy and, particularly, safety, and must be considered in EVAR surveillance protocols so that its use becomes widespread. We understand that CEUS, as a surveillance exam, considerably reduces risks to patients compared to CTA.

Dose reduction using digital fluoroscopy versus digital subtraction angiography in endovascular aneurysm repair: A prospective randomized trial.

OBJECTIVE: Endovascular aneurysm repair (EVAR) can result in high radiation dose to patients and operators. This prospective randomized study aimed to assess whether patient radiation dose sustained during EVAR could be decreased by predominantly using digital fluoroscopy (DF) vs the standard technique using digital subtraction angiography (DSA). METHODS: Between February 2011 and June 2017, patients with EVAR of infrarenal abdominal aortic aneurysms were prospectively enrolled and randomly assigned to a standard treatment DSA cohort or a DF cohort in which two or fewer DSA acquisitions were allowed for confirmatory imaging. Primary end points included dose-area product (DAP) and cumulative air kerma. Secondary end points included technical success and conversion to DSA standard treatment (if DF was inadequate for visualization). RESULTS: For all 43 patients enrolled (26 in the DF cohort, 17 in the DSA cohort), technical success was 100%. Of the 26 DF patients, 5 (19%) required conversion to the DSA cohort. In an intention-to-treat analysis, mean DAP was significantly lower in the DF cohort than in the DSA cohort (132 vs 174 Gy·cm2; P = .04). When patients were separated by number of DSA acquisitions (two or fewer vs three or more), mean DAP decreased 41% (109 vs 185 Gy·cm2; P = .005) and cumulative air kerma decreased 40% (578 vs 964 mGy; P = .004). CONCLUSIONS: In most patients (81%), DF or limited DSA was adequate for visualization during EVAR. In both intention-to-treat DF and limited-DSA cohorts, mean DAP was significantly decreased. If image quality allows, a DF-only or limited-DSA approach to EVAR decreases radiation dose.

The benefit of combined carbon dioxide automated angiography and fusion imaging in preserving perioperative renal function in fenestrated endografting.

BACKGROUND: Contrast-induced nephropathy is a possible adverse event in fenestrated endovascular aneurysm repair (FEVAR). Automated carbon dioxide (CO2) angiography has been proposed as an alternative to iodinated contrast medium (ICM) for standard endovascular aneurysm repair; however, its use in FEVAR has not yet been investigated. The aim of this study was to analyze the possibility of reducing the amount of procedural ICM during FEVAR by combining CO2 with intraprocedural three-dimensional preoperative computed tomography angiography images overlaid on two-dimensional live fluoroscopy images (fusion imaging [FI]). METHODS: Between January and April 2018, juxtarenal and pararenal abdominal aortic aneurysms and type IV thoracoabdominal aortic aneurysms undergoing FEVAR with a CO2 + FI protocol were prospectively collected and compared with FEVAR cases treated with standard procedural imaging (ICM + FI) between June and December 2017. Preoperative, intraoperative, and postoperative data were analyzed. Amount of ICM, procedure and fluoroscopy time, total radiation dose (dose-area product), endoleaks, and technical success (defined as absence of type I or type III endoleak and target visceral vessel patency at completion angiography) were assessed. The 30-day renal function worsening (estimated glomerular filtration rate reduction >25% of the preoperative value) and 6-month reinterventions were also considered. Analysis was done by Fisher exact and Mann-Whitney tests. RESULTS: Forty-five patients were enrolled, 15 (33%) managed by CO2 + FI and 30 (67%) by ICM + FI. The two groups were homogeneous in their clinical, anatomic, and endograft features. Median ICM administration was significantly lower in CO2 + FI compared with ICM + FI (41 mL [interquartile range (IQR), 26 mL] vs 138.5 mL [IQR, 88 mL]; P = .001). There was no difference in median procedure time, fluoroscopy time, and dose-area product between CO2 + FI and ICM + FI. Intraoperative type I or type III endoleak detection was similar (P = 1) in CO2 + FI (7%) and ICM + FI (7%), with immediate repair and technical success achieved in all cases. Early type II endoleak did not differ in the two groups (CO2 + FI, 27%; ICM + FI, 20%; P = .7). Postoperative renal function deteriorated in two patients (13%) in the CO2 + FI group vs eight patients (27%) in the ICM + FI group (P = .04). The median increase of postoperative creatinine concentration was smaller in the CO2 + FI group than in the ICM + FI group (0.09 mg/dL [IQR, 0.03 mg/dL] vs 0.3 mg/dL [IQR, 0.4 mg/dL]; P = .04). The median hospitalization time was shorter in the CO2 + FI group (5 days [IQR, 1 day] vs 8 days [IQR, 4 days]; P = .002). No reintervention was necessary at 30-day and 6-month follow-up in either group. CONCLUSIONS: CO2 + FI is safe and effective in FEVAR and allows the amount of ICM to be significantly reduced, leading to shorter hospitalization time and better renal function preservation at 30 days. Technical success, procedure and fluoroscopy time, radiation dose, and 6-month reinterventions are comparable with those of the standard ICM imaging protocol for FEVAR. Based on this preliminary experience, CO2 + FI may be proposed as an effective tool to reduce the overall amount of procedural ICM, with consequent benefits on perioperative renal function.

Validation of a New Method for 2D Fusion Imaging Registration in a System Prepared Only for 3D.

Purpose: To validate a new 2D-3D registration method of fusion imaging during aortic repair in a system prepared only for 3D-3D registration and to compare radiation doses and accuracy. Materials and Methods: The study involved 189 patients, including 94 patients (median age 70 years; 85 men) who underwent abdominal endovascular aneurysm repair (EVAR) with 2D-3D fusion on an Artis zee imaging system and 95 EVAR patients (median age 70 years; 81 men) from a prior study who had 3D-3D registration done using cone beam computed tomography (CBCT). For the 2D-3D registration, an offline CBCT of the empty operating table was imported into the intraoperative dataset and superimposed on the preoperative computed tomography angiogram (CTA). Then 2 intraoperative single-frame 2D images of the skeleton were aligned with the patient's skeleton on the preoperative CTA to complete the registration process. A digital subtraction angiogram was done to correct any misalignment of the aortic CTA volume. Values are given as the median [interquartile range (IQR) Q1, Q3]. Results: The 2D-3D registration had an accuracy of 4.0 mm (IQR 3.0, 5.0) after bone matching compared with the final correction with DSA (78% within 5 mm). By applying the 2D-3D protocol the radiation exposure (dose area product) from the registration of the fusion image was significantly reduced compared with the 3D-3D registration [1.12 Gy∙cm2 (IQR 0.41, 2.14) vs 43.4 Gy∙cm2 (IQR 37.1, 49.0), respectively; p<0.001). Conclusion: The new 2D-3D registration protocol based on 2 single-frame images avoids an intraoperative CBCT and can be used for fusion imaging registration in a system originally designed for 3D-3D only. This 2D-3D registration protocol is accurate and leads to a significant reduction in radiation exposure.

Modern Image Acquisition System Reduces Radiation Exposure to Patients and Staff During Complex Endovascular Aortic Repair.

OBJECTIVE: Radiation damage during complex endovascular aortic repair (EVAR) is of major concern to patients and medical staff. This study investigates primarily the influence of different acquisition systems (Allura ClarityIQ vs. Allura Xper, Philips Healthcare, Best, the Netherlands) on radiation dose. Secondly, radiation exposure was analysed for operator positions as well as for procedure and patient specific parameters. METHODS: This was a retrospective study of prospectively collected data. The study prospectively included 62 consecutive patients (mean age 71.2 ± 8.4 years; 63% males) who underwent complex EVAR including fenestrated or branched EVAR of the thoraco-abdominal or the aortic arch from 30 June 2015 to 20 May 2016. In half the patients an advanced dose and real time image noise reduction technology (Allura ClarityIQ) was used, and in the other half the reference acquisition system (Allura Xper) was used. Patient demographics included age, gender, and body mass index. RESULTS: Sixty-two patients with mean age of 71.2 ± 8.4 years (63% males; 39/62) were treated using either Allura ClarityIQ or Allura Xper. Patients treated using Allura ClarityIQ had lower cumulative dose area product (18,948.3 ± 14,648.5 cGy cm2vs. 38,512.4 ± 24,105.4 cGy cm2, p < 0.001) and air kerma (2237.9 ± 1808 mGy vs. 4031 ± 3260.2 mGy, p = .010) in comparison with patients treated using Allura Xper. CONCLUSION: Advanced dose and real time image noise reduction technology, such as Allura ClarityIQ, is a useful tool to lower the amount of radiation for patient and staff during complex endovascular aortic procedures.

Three-dimensional image fusion is associated with lower radiation exposure and shorter time to carotid cannulation during carotid artery stenting.

OBJECTIVE: Three-dimensional (3D) image fusion is associated with lower radiation exposure, contrast agent dose, and operative time during endovascular abdominal aortic aneurysm repair. Therefore, we evaluated the impact of this technology on carotid artery stenting (CAS). METHODS: We identified consecutive CAS procedures from 2009 to 2017 and compared those performed with and without 3D image fusion. For image fusion, we created a 3D reconstruction of the aortic arch anatomy based on preoperative computed tomography or magnetic resonance angiography that we merged with two-dimensional fluoroscopy, allowing 3D image overlay. We compared radiation exposure, fluoroscopy time, contrast agent dose, time to common carotid artery (CCA) cannulation, time from CCA cannulation to completion angiography, and total procedure time in procedures with and without image fusion. We also assessed rates of 30-day stroke/death, in-hospital and 30-day stroke, and acute kidney injury. We used multivariable linear regression to adjust for patient and procedural characteristics and used these models to compute the marginal effects of image fusion compared with no image fusion. RESULTS: There were 46 patients who underwent CAS with a 3D image fusion system and 70 patients without. Patients undergoing CAS with image fusion experienced 31% lower radiation exposure compared with the control group (207 ± 23 mGy vs 300 ± 26 mGy, respectively; P < .01), shorter fluoroscopy time (21 ± 6 minutes vs 24 ± 8 minutes; P = .02), shorter time to carotid cannulation (21 ± 9 minutes vs 31 ± 8 minutes; P < .001), and shorter total procedure time (47 ± 13 minutes vs 54 ± 18 minutes; P = .03). There was no difference in contrast material volume, time from CCA cannulation to completion angiography, or total in-room time. After multivariable adjustment, 3D image fusion remained associated with lower radiation dose, shorter fluoroscopy time, and shorter time to carotid cannulation (all P < .05). The rate of 30-day stroke/death was 2.7% (three strokes and no deaths at 30 days), and the rate of acute kidney injury was 1.8%. CONCLUSIONS: CAS with 3D image fusion was associated with lower radiation exposure and shorter time to CCA cannulation. These results represent the potential technical advantage gained with image fusion and add to the growing body of evidence demonstrating its impact on radiation exposure and operative times during complex endovascular procedures.

A population-based cohort study examining the risk of abdominal cancer after endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Endovascular aneurysm repair (EVAR) has increasingly been used as the primary treatment approach for abdominal aortic aneurysm (AAA). This study examined the hypothesis that EVAR leads to an increased risk of abdominal cancer within the radiation field compared with open AAA repair. METHODS: The nationwide English Hospital Episode Statistics database was used to identify all patients older than 50 years who received an AAA repair in 2005 to 2013. EVAR and open AAA repair groups were compared for the incidence of postoperative cancer using inverse probability weights and G-computation formula to adjust for selection bias and confounding. RESULTS: Among 14,150 patients who underwent EVAR and 24,645 patients who underwent open AAA repair, follow-up was up to 7 years. EVAR was associated with an increased risk of postoperative abdominal cancer (hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.03-1.27) and all cancers (HR, 1.09; 95% CI, 1.02-1.17). However, there was no difference between the groups in the risk of lung cancer (HR, 1.04; 95% CI, 0.92-1.18) or obesity-related nonabdominal cancer (HR, 1.12; 95% CI, 0.69-1.83). Within the EVAR group, use of computed tomography surveillance was not associated with any increased risk of abdominal cancer (HR, 0.94; 95% CI, 0.71-1.23) or all cancers (HR, 0.97; 95% CI, 0.81-1.17). CONCLUSIONS: This study suggests an increased risk of abdominal cancer after EVAR compared with open AAA repair. The differential cancer risk should be further explored in alternative national populations, and radiation exposure during EVAR should be measured as a quality metric in the assessment of EVAR centers.

Impact of onlay fusion and cone beam computed tomography on radiation exposure and technical assessment of fenestrated-branched endovascular aortic repair.

OBJECTIVE: The objective of this study was to analyze the impact of advanced imaging applications and cone beam computed tomography (CBCT) on radiation exposure of the patient and operator and detection of technical problems during fenestrated-branched endovascular aortic repair (F-BEVAR) for treatment of pararenal aneurysms and thoracoabdominal aortic aneurysms (TAAAs). METHODS: We reviewed the clinical data of 386 consecutives patients (289 male; mean age, 75 ± 8 years) treated by F-BEVAR for 196 pararenal aneurysms and 190 TAAAs (mean, 3.4 ± 0.9 targeted vessels/patient) between 2007 and 2017. Radiation exposure (cumulative air kerma) was analyzed in three fixed imaging systems used between 2007 and 2011 (system 1), 2012 and 2016 (system 2), and 2016 and 2017 (system 3). Onlay fusion and CBCT were available with systems 2 and 3, whereas digital zoom with fusion overlay was used with system 3. Operator effective dose was measured per month using a radiation dosimeter badge. Computed tomography angiography and CBCT were analyzed for findings requiring immediate revision or secondary interventions. End points were patient radiation exposure; operator effective dose; procedure technical success; and 30-day rates of mortality, major adverse events, and secondary interventions. RESULTS: F-BEVAR was performed using system 1 in 98 patients, system 2 in 198 patients, and system 3 in 90 patients. Use of onlay fusion/CBCT was 0% with system 1, 42% with system 2, and 98% with system 3. Procedures performed with onlay fusion/CBCT had significantly (P < .05) higher technical success (99.4% vs 98.8%) and lower contrast material volume (155 ± 58 mL vs 172 ± 80 mL), fluoroscopy time (83 ± 34 minutes vs 94 ± 49 minutes), and cumulative air kerma (2561 ± 1920 mGy vs 3767 ± 2307 mGy). Despite higher case volume and increasing complexity during the experience, operator effective dose decreased to 9 ± 4 × 10-2 mSv/case with system 3 compared with 26 ± 3 × 10-2 mSv/case with system 1 and 20 ± 2 × 10-2 mSv/case with system 2 (P = .001). Among 219 patients who had no CBCT, 18 (8%) had computed tomography angiography findings that prompted secondary interventions before dismissal. Conversely, among 167 patients who had CBCT, 14 patients (8%) had intraoperative CBCT findings requiring immediate revision, with no additional secondary interventions. Patients treated with onlay fusion/CBCT had significantly (P < .05) lower mortality (4% vs 1%), major adverse events (43% vs 19%), and secondary interventions (10% vs 4%) at 30 days. CONCLUSIONS: Radiation exposure and operator effective dose significantly decreased with evolution of F-BEVAR experience and use of advanced imaging applications such as onlay fusion and CBCT. CBCT allowed immediate assessment and identified intraoperative technical problems, leading to immediate revision and avoiding early secondary interventions.

Image fusion using the two-dimensional-three-dimensional registration method helps reduce contrast medium volume, fluoroscopy time, and procedure time in hybrid thoracic endovascular aortic repairs.

OBJECTIVE: The objective of this study was to evaluate the effect of image fusion (IF) technology in thoracic endovascular aortic repair (TEVAR) on reducing radiation exposure (dose and time), amount of injected iodinated contrast medium needed, and procedure time. METHODS: We performed a review of our institutional endovascular aortic database of patients who had undergone TEVAR between 2008 and 2016 before and after the installation of a three-dimensional (3D) IF computed tomography system in our hybrid operating room. All patients were operated on using the same radiologic equipment with or without IF. RESULTS: The 146 patients who had undergone elective or emergent TEVAR with preoperative computed tomography angiography done in 1-mm-thick slices were divided into two groups: the IF group (98 patients), in which TEVAR was performed using intraoperative IF with the two-dimensional-3D registration method; and 48 controls without the use of IF. The IF group received a significantly reduced dose of contrast material, with a median of 70 mL (interquartile range [IQR], 50-101 mL) compared with controls receiving 104 mL (IQR, 69-168 mL; P < .001).Patients who underwent hybrid TEVAR had a significantly reduced procedure time under IF guidance (n = 25) compared with controls (n = 11; median, 162 minutes [IQR, 139-199 minutes] vs 213 minutes [IQR, 189-298 minutes]; P = .015). In addition, the intraoperative fluoroscopy time was reduced to 9 minutes (IQR, 6-13 minutes) vs 23 minutes (IQR, 12-45 minutes; P < .005). However, the radiation dose (dose-area product) was similar for the two groups (P = .37).In patients who underwent plain TEVAR (n = 74) without a carotid-subclavian bypass, the IF group needed significantly less contrast material (median, 64 mL [IQR, 43-81 mL]) compared with the control group (median, 98 mL [IQR, 60-180 mL]; P = .003), whereas intraoperative radiation exposition, procedure time, and fluoroscopy time did not statistically significantly differ between the two groups. CONCLUSIONS: The IF technology using the two-dimensional-3D registration method was associated with reduced intraoperative contrast material volume in performing TEVAR. IF seemed to shorten the operation and radiation times in the more complicated (hybrid) TEVAR cases. However, a prospective study is needed to look at the dose-area product, fluoroscopy time, and procedure time in a larger cohort of patients.

Comparison of Patient Radiation Dose and Contrast Use during EVAR in a Dedicated Hybrid Vascular OR and Mobile Imaging.

BACKGROUND: The aim of the study is to determine whether performing endovascular aortic aneurysm repair (EVAR) in a dedicated vascular hybrid operating room (OR) is associated with a decreased patient radiation and contrast dose compared with mobile C-arm imaging in a conventional OR. METHODS: This is a retrospective study of patients undergoing standard EVAR from 2009-2016. "Standard EVAR" was defined as the elective EVAR performed with bifurcated graft for infrarenal aneurysm with no iliac aneurysms. Patients were divided into 2 groups. Group 1 included EVARs performed in conventional theater with a mobile C-arm (January 2009 to June 2012) and group 2 EVARs performed in the dedicated vascular hybrid OR (July 2012 to December 2016). Data collected included patient demographics, aneurysm diameter, neck length, radiation dose, screening time, and contrast use of each patient. RESULTS: There were 286 patients, 78 and 208 patients in group 1 and 2, respectively. There was no difference in age (77.6 years [76.3-78.9] vs. 76.6 years [75.9-77.9], P > 0.05), body mass index (26.5 kg/m2 [25.1-28.0] vs. 27.9 kg/m2 [27.1-28.7] P > 0.05), and mean aneurysm diameter (6.48 cms [6.13-6.82] vs. 6.81 cms [6.0-7.7], P > 0.05) between groups. Patients in group 2 received approximately half the mean radiation dose (16,807 cGy cm2 [±11,078] vs. 8,233 cGy cm2 [±7,471], P < 0.001), shorter fluoroscopy time (36.02 min [±21.3] vs. 26.96 min [±19], P = 0.001), and less contrast use (114 mls [±44.2] vs. 158 mls [±63.9], P < 0.001). CONCLUSIONS: Performing EVAR in a dedicated vascular Hybrid OR may be associated with a lower patient radiation dose, shorter screening time, and less contrast use than performing EVAR in a conventional OR.

Fusion Imaging for EVAR with Mobile C-arm.

BACKGROUND: Fusion imaging is a technique that facilitates endovascular navigation but is only available in hybrid rooms. The goal of this study was to evaluate the feasibility of fusion imaging with a mobile C-arm in a conventional operating room through the use of an angionavigation station. METHODS: From May 2016 to June 2017, the study included all patients who underwent an aortic stent graft procedure in a conventional operating room with a mobile flat-panel detector (Cios Alpha, Siemens) connected to an angionavigation station (EndoNaut, Therenva). The intention was to perform preoperative 3D computerized tomography/perioperative 2D fluoroscopy fusion imaging using an automatic registration process. Registration was considered successful when the software was able to correctly overlay preoperative 3D vascular structures onto the fluoroscopy image. For EVAR, contrast dose, operation time, and fluoroscopy time (FT) were compared with those of a control group drawn from the department's database who underwent a procedure with a C-arm image intensifier. RESULTS: The study included 54 patients, and the procedures performed were 49 EVAR, 2 TEVAR, 2 IBD, and 1 FEVAR. Of the 178 registrations that were initialized, it was possible to use the fusion imaging in 170 cases, that is, a 95.5% success rate. In the EVAR comparison, there were no difference with the control group (n = 103) for FT (21.9 ± 12 vs. 19.5 ± 13 min; P = 0.27), but less contrast agent was used in the group undergoing a procedure with the angionavigation station (42.3 ± 22 mL vs. 81.2 ± 48 mL; P < 0.001), and operation time was shorter (114 ± 44 vs. 140.8 ± 38 min; P < 0.0001). CONCLUSIONS: Fusion imaging is feasible with a mobile C-arm in a conventional operating room and thus represents an alternative to hybrid rooms. Its clinical benefits should be evaluated in a randomized series, but our study already suggests that EVAR procedures might be facilitated with an angionavigation system.

Radiation doses for endovascular aortic repairs performed on mobile and fixed C-arm fluoroscopes and procedure phase-specific radiation distribution.

OBJECTIVE: The objective of this study was to analyze radiation risk to patients during endovascular aneurysm repair (EVAR) using mobile C-arm (MA) or fixed C-arm (FA) fluoroscopes and to describe the dose distribution during the different phases of the procedure. METHODS: Patients treated with EVAR using a single stent graft system between November 2009 and June 2016 were included in this study. The patients were divided into one of two groups (MA or FA) according to the type of C-arm used in the procedure. Data regarding patients' demographics and the total amount of contrast agent (CA) used, dose-area product, and fluoroscopy time for the procedures were prospectively recorded. Based on the dose report from the FA system, five standard and two optional phases of the procedure were identified to determine the dose distribution. RESULTS: Overall, 160 patients were included (mean age, 73.30 ± 8.97 years; 146 men); of these, 107 were treated with an MA system and 53 were treated with an FA system. The mean amounts of CA used were 108.55 ± 42.28 mL in the MA group and 85.37 ± 38.79 mL in the FA group (P = .0014). The mean total dose-area product values were 49.93 ± 38.06 Gy·cm2 in the MA group and 168.34 ± 146.92 Gy·cm2 in the FA group (P < .0001). There was no significant difference in fluoroscopy time between the groups. Per-phase analysis demonstrated that identification of the proximal landing zone and main body deployment required the most radiation, accounting for 24% of the total radiation dose. Overall, 47.6% of the exposure was due to digital subtraction angiography. CONCLUSIONS: Use of an FA system can significantly reduce the amount of CA needed but may also lead to higher radiation doses in EVAR procedures. Dose monitoring remains crucial for the safety of both patients and operators. A detailed analysis of dose distribution is possible with modern systems, which may improve the quality of monitoring in the future.

Endovascular aortic sealing with Nellix reduces intraoperative radiation dose when compared to endovascular aortic repair.

OBJECTIVE: To analyze radiation exposure during endovascular aortic sealing (EVAS) in comparison with standard endovascular aortic repair (EVAR) in clinical practice. METHODS: From December 2013 to October 2016 (35 months), 60 patients were analyzed for intraoperative radiation exposure during EVAR: 30 consecutive patients (mean age, 73.10 years; 28 male) received EVAS (Nellix Endologix); within the same time frame, 30 patients were treated with standard EVAR (mean age, 71.87 years; 30 male). An indirect dose analysis was performed for both groups of patients, including effective dose and cumulative air kerma. Furthermore, fluoroscopy time (FT), dose area product, and time of procedure were included in the study. RESULTS: The effective dose was significantly reduced in the EVAS group (3.72 mSv) compared with the group treated with standard EVAR (6.8 mSv; P ≤ .001). The cumulative air kerma was also lowered in EVAS (67.65 mGy vs 139 mGy in EVAR; P ≤ .001). FT for the entire group was 13 minutes and was shorter (P < .001) for EVAS (9 minutes) in comparison with EVAR (19 minutes). The dose area product for the entire cohort was 16.95 Gy.cm2 and was lower during EVAS (12.4 Gy.cm2) than during EVAR (22.6 Gy.cm2; P < .001). The median operating time for the entire group was 123.5 minutes and was significantly shorter (P < .01) for EVAS (119 minutes vs EVAR at 132 minutes). The FT shows a significant correlation with the patient's weight (P = .022), body mass index (P = .004), and time of procedure (P = .005). CONCLUSIONS: EVAS is associated with a relevant decrease in indirect measured radiation dose and time of procedure compared with standard EVAR. A relevant reduction in dose during EVAS is highly likely to result in lower exposure to radiation for physicians and staff. Such a result would be highly advantageous and calls for further analysis.

A prospective observational trial of fusion imaging in infrarenal aneurysms.

OBJECTIVE: Use of three-dimensional fusion has been shown to significantly reduce radiation exposure and contrast material use in complex (fenestrated and branched) endovascular aneurysm repair (EVAR). Cydar software (CYDAR Medical, Cambridge, United Kingdom) is a cloud-based technology that can provide imaging guidance by overlaying preoperative three-dimensional vessel anatomy from computed tomography scans onto live fluoroscopy images both in hybrid operating rooms and on mobile C-arms. The aim of this study was to determine whether radiation dose reduction would occur with the addition of fusion imaging to infrarenal repair in all imaging environments. METHODS: All patients who consented to involvement in the trial and who were treated with EVAR in our center from March 2016 until April 2017 were included. A teaching session about radiation protection and Cydar fusion software use was provided to all operators before the start of the fusion group enrollment. This group was compared with a retrospective cohort of patients treated in the same center from March 2015 to March 2016, after a dedicated program of radiation awareness and reduction was introduced. Ruptured aneurysms and complex EVAR were excluded. Preoperative and perioperative characteristics were recorded, including parameters of radiation dose, such as air kerma and dose-area product. Results were expressed in median and interquartile range. RESULTS: Forty-four patients were prospectively enrolled and compared with 21 retrospective control patients. No significant differences were found in comparing sex, body mass index, and age at repair. The median operation time (wire to wire) and fluoroscopy time were 90 (75-105) minutes and 30 (22-34) minutes, respectively, without significant differences between groups (P = .56 and P = .36). Dose-area product was nonsignificantly higher in the control group, 21.7 (8.9-85.9) Gy cm2, compared with the fusion group, 12.4 (7.5-23.4) Gy cm2 (P = .10). Air kerma product was significantly higher in the control group, 142 (61-541) mGy, compared with 82 (51-115) mGy in the fusion group (P = .03). The number of digital subtraction angiography runs was significantly lower in the fusion group (8 [6-11]) compared with the control group (10 [9-14]); (P = .03). There were no significant differences in the frequency of adverse events, endoleaks, or additional procedures required. CONCLUSIONS: When it is used in simple procedures such as infrarenal aneurysm repair, image-based fusion technology is feasible both in hybrid operating rooms and on mobile systems and leads to an overall 50% reduction in radiation dose. Fusion technology should become standard of care for centers attempting to maximize radiation dose reduction, even if capital investment of a hybrid operating room is not feasible.