Computational prediction of proximal sealing in endovascular abdominal aortic aneurysm repair with unfavorable necks.

BACKGROUND AND OBJECTIVE: Endovascular aortic aneurysm repair (EVAR) has become the standard treatment for abdominal aortic aneurysms in most centers. However, proximal sealing complications leading to endoleaks and migrations sometimes occur, particularly in unfavorable aortic anatomies and are strongly dependent on biomechanical interactions between the aortic wall and the endograft. The objective of the present work is to develop and validate a computational patient-specific model that can accurately predict these complications. METHODS: Based on pre-operative CT-scans, we developed finite element models of the aorta of 10 patients who underwent endovascular aortic aneurysm repair, 7 with standard morphologies and 3 with unfavorable anatomies. We simulated the deployment of stent grafts in each aorta by solving mechanical equilibrium with a virtual shell method. Eventually we compared the actual stent ring positions from post-operative computed-tomography-scans with the predicted simulated positions. RESULTS: A successful deployment simulation could be performed for each patient. Relative radial, transverse and longitudinal deviations were 6.3 ± 4.4%, 2.5 ± 0.9 mm and 1.4 ± 1.1 mm, respectively. CONCLUSIONS: The numerical model predicted accurately stent-graft positions in the aortic neck of 10 patients, even in complex anatomies. This shows the potential of computer simulation to anticipate possible proximal endoleak complications before EVAR interventions.

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.

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.

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.

[Isolated iliac artery aneurysm : Clinical background and interventional treatment strategies]. / Isolierte Iliakalarterienaneurysmen : Klinischer Hintergrund und interventionelle Versorgungsstrategien.

BACKGROUND: Isolated iliac artery aneurysms are less frequent than abdominal aortic aneurysms, with the same, predominantly atherosclerotic-degenerative etiology, but patients present more frequently with symptoms or at the stage of rupture. The majority of those affected are men over the age of 65. The ideal imaging technique for diagnosis, treatment planning and follow-up is computed tomography (CT) angiography. Below a diameter of 4 cm, the risk of rupture is 6.3%, and then increases significantly with increasing diameter. Today, treatment is recommended from a size of 3.5 cm at the earliest. THERAPY: Because of the lower mortality, endovascular therapy is the leading treatment for the elective and emergency situation. The quality of the landing zones, which are important for sealing, is decisive for elimination of the aneurysm. The elimination is carried out by means of stent grafts, often in combination with embolization. Due to the risk of buttock claudication and erectile dysfunction, the preservation of ipsilateral pelvic perfusion is recommended in cases of insufficient collateralization. Special iliac branch devices or various parallel endograft techniques are available for this purpose. FOLLOW-UP: The main problem of endovascular treatment are endoleaks and the associated need for reintervention. Imaging control by means of CT angiography is crucial for timely endoleak detection, especially in the early phase.

Revascularization of Left Subclavian to Common Carotid Artery Prepares for Covered Stent Implantation in Patients With Complex Aortic Coarctation.

Seven adult patients underwent a two-stage treatment of complex coarctation (CoA), including surgical revascularization of the left subclavian artery (LSA) to left common carotid artery (LCCA), followed by transcatheter covered stent implantation. The majority of patients (5 of 7, 71%) received 1 covered stent (covered Cheatham Platinum stent: 8 zig/45 mm [n = 2], 10 zig/60 mm [n = 1], 10 zig/65 mm [n = 1]; BeGraft: 24/48 mm [n = 2]). In 1 patient (14%), the implantation of 2 covered stents (BeGraft 20/48 mm) was necessary. During a median follow-up of 2.4 years (interquartile range, 0.1 to 4.9 years), complications occurred in 3 of 7 patients (43%), including an asymptomatic but severe stenosis of the LSA bypass (n = 1), a recoarctation with a mild endoleak (n = 1), and a severe endoleak (n = 1). Surgical revascularization of the LSA to the LCCA can successfully prepare for covered stent implantation in complex CoA in adult patients. This two-stage approach was feasible and safe with complications occurring in 3 of 7 patients (43%). All complications were managed by catheter reintervention only.

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.

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.

Time-Resolved, Dynamic Computed Tomography Angiography for Characterization of Aortic Endoleaks and Treatment Guidance via 2D-3D Fusion-Imaging.

In the United States, more than 80% of all abdominal aortic aneurysms are treated by endovascular aortic aneurysm repair (EVAR). The endovascular approach warrants good early results, but adequate follow-up imaging after EVAR is imperative to maintain long-term positive outcomes. Potential graft-related complications are graft migration, infection, fraction, and endoleaks, with the last one being the most common. The most frequently used imaging after EVAR is computed tomography angiography (CTA) and duplex ultrasound. Dynamic, time-resolved computed tomography angiography (d-CTA) is a reasonably new technique to characterize the endoleaks. Multiple scans are done sequentially around the endograft during acquisition that grants good visualization of the contrast passage and graft-related complications. This high diagnostic accuracy of d-CTA can be implemented into therapy via image fusion and reduce additional radiation and contrast material exposure. This protocol describes the technical aspects of this modality: patient selection, preliminary image review, d-CTA scan acquisition, image processing, qualitative and quantitative endoleak characterization. The steps of integrating dynamic CTA into intra-operative fluoroscopy using 2D-3D fusion-imaging to facilitate targeted embolization are also demonstrated. In conclusion, time-resolved, dynamic CTA is an ideal modality for endoleak characterization with additional quantitative analysis. It can reduce radiation and iodinated contrast material exposure during endoleak treatment by guiding interventions.

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.

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.

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.

Low dose contrast CT for transcatheter aortic valve replacement assessment: Results from the prospective SPECTACULAR study (spectral CT assessment prior to TAVR).

BACKGROUND: Computed tomographic angiography (CTA) based planning for transcatheter aortic valve replacement (TAVR) is essential for reduction of periprocedural complications. Spectral CT based imaging provides several advantages, including better contrast/signal to noise ratio and increased soft tissue contrast, permitting better delineation of contrast filled structures at lower doses of iodinated contrast media. The aim of this prospective study was to assess the initial feasibility of a low dose iodinated contrast protocol, utilizing monoenergetic 40 keV reconstruction, using a dual-layer CT scanner (DLCT) for CTA in patients undergoing TAVR planning. METHODS: 116 consecutive TAVR patients underwent a gated chest and a non-gated CTA of the abdomen and pelvis. 40 keV virtual monoenergetic images (VMI) were reconstructed and compared with conventional polychromatic images (CI). The proximal aorta and access vessels were scored for image quality by independent experienced cardiovascular imagers. RESULTS: Proximal aortic image quality as assessed by signal to noise (SNR) and contrast to noise ratio (CNR), were significantly better with 40 keV VMI relative to CI (SNR 14.65 ±â€¯7.37 vs 44.16 ±â€¯22.39, p < 0.001; CNR 15.84 ±â€¯9.93 vs 59.8 ±â€¯40.83, p < 0.001). Aortic root dimensions were comparable between the two approaches with a bias towards higher measurements at 40 keV (Bland Altman). SNR and CNR in all access vessel segments at 40 keV were substantially better (p < 0.001 for all peripheral access vessel segments) with comparable image quality. CONCLUSION: 40 keV VMI with low dose contrast dose spectral imaging is feasible for comprehensive preprocedural evaluation of access vessels and measurements of aortic root dimensions in patients undergoing TAVR.

Comparison of endovascular aneurysm sealing and repair with respect to contrast use and radiation in comparable patient cohorts.

BACKGROUND: Due to recent advances in endograft design and percutaneous access, technical success could be increased during endovascular aneurysm repair (EVAR). Beside EVAR, endovascular aneurysm sealing (EVAS) provides an alternative procedure to treat aneurysms. To compare the two methods, additional benchmark criteria should be evaluated: Screening time, dose area product (DAP), procedure time and contrast use. In this study these technical variables are analyzed for EVAS vs. EVAR in comparable patient cohorts. METHODS: It is a retrospective, single-center study. Only elective cases of infrarenal aortic aneurysms were included, all treated by the same surgeon (D.B.). Procedures were performed within the instructions for use without additional procedures. All operations were undertaken in a hybrid operating theatre. For EVAR, only the Medtronic Endurant® and the Gore C3 Excluder® were included. For EVAS the Nellix® from Endologix was used. RESULTS: Between 2012 and 2016, 67 patients were treated with EVAS and 40 with EVAR; of these 20 and 16 could be introduced into the study respectively. Median age was 73 and 72 years respectively (only men). The two groups were comparable in terms of BMI, GFR and ASA-status. Screening time was reduced for EVAS (10.6 vs. 14.5 min., P<0.01), while the DAP was not significantly different. Procedural time and contrast use were increased for EVAS (120 vs. 96 min., 120 vs. 79 mL, P<0.01). CONCLUSIONS: Especially the younger EVAS-procedure requires ongoing review in order to further reduce contrast agent. Reduced screening time for EVAS does not have a significant impact on radiation dose.

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.

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.

Safety and Risk of Major Complications With Diagnostic Cardiac Catheterization.

BACKGROUND: We aim to study the incidence of major complications related to procedure defined as in-hospital death, myocardial infarction, stroke, pericardial effusion or tamponade, percutaneous coronary intervention due to iatrogenic coronary dissection, or unplanned bypass surgery within 72 hours after diagnostic left heart catheterization (LHC; primary end point). Furthermore, all causes of in-hospital death after LHC were adjudicated and reported (secondary end point). METHODS AND RESULTS: Diagnostic LHC procedures (aortic angiography; coronary, including graft, angiography; and left ventricular angiography) from January 1, 2002, through December 31, 2013, were identified using the clinical scheduling system at Mayo Clinic, Rochester, and complications were identified through electronic records. International Classification of Diseases, Ninth Revision billing codes were used. Registration was queried to identify all-cause mortality. All events were reviewed and adjudicated. There were 43 786 diagnostic LHC procedures; 97.3% were coronary angiograms. The mean age of patients was 64.5 years (13.6), and the majority were male (61.5%). Primary end point was seen in 36 (0.082%) procedures or 8.2 of 10 000 LHCs. Combined right sided procedures with LHC did not increase the risk of major complications. Cardiogenic and septic shock, cardiac arrhythmia, and postsurgical complication were the most common causes of in-hospital death after LHC. CONCLUSIONS: The overall rates of major complications related to diagnostic cardiac catheterization procedures are extremely rare. The majority of the deaths occurring post-diagnostic LHC procedures were secondary to acute illness rather than directly related to diagnostic procedure.

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.