Surgeon radiation dose during complex endovascular procedures

Lowest reported dose area product of 2.4 Gy∗cm2 for ultra-low-dose endovascular aortic aneurysm repair of a standard infrarenal aortic aneurysm

This is a report of successful treatment of an abdominal aortic aneurysm via standard endovascular aortic repair with an ultra-low dose (ULD) of 2.4 Gy∗cm2 using the latest imaging software in a hybrid operating room. To the best of our knowledge, no case has yet been reported achieving a successful outcome with such ULD values to date. The key factors to achieving an ULD regarding the dose area product comprise the right technology, procedural standardization, and team education and training. This case highlights the potential for reducing the radiation dose routinely for patients and staff alike, especially for operating room staff with daily radiation exposure.

A procedural step analysis of radiation exposure in fenestrated endovascular aortic repair

OBJECTIVE

Radiation exposure during complex endovascular aortic repair may be associated with tangible adverse effects in patients and operators. This study aimed to identify the steps of highest radiation exposure during fenestrated endovascular aortic repair (FEVAR) and to investigate potential intraoperative factors affecting radiation exposure.

METHODS

Prospective data of 31 consecutive patients managed exclusively with four-fenestration endografts between March 1, 2020, and July 1, 2022 were retrospectively analyzed. Leveraging the conformity of the applied technique, every FEVAR operation was considered a combination of six overall stages composed of 28 standardized steps. Intraoperative parameters, including air kerma, dose area product, fluoroscopy time, and number of digital subtraction angiographies (DSAs) and average angulations were collected and analyzed for each step.

RESULTS

The mean procedure duration and fluoroscopy time was 140 minutes (standard deviation [SD], 32 minutes), and 40 minutes (SD, 9.1 minutes), respectively. The mean air kerma was 814 mGy (SD, 498 mGy), and the mean dose area product was 66.8 Gy cm2 (SD, 33 Gy cm2). The percentage of air kerma of the entire procedure was distributed throughout the following procedure stages: preparation (13.9%), main body (9.6%), target vessel cannulation (27.8%), stent deployment (29.1%), distal aortoiliac grafting (14.3%), and completion (5.3%). DSAs represented 23.0% of the total air kerma. Target vessel cannulation and stent deployment presented the highest mean lateral angulation (67 and 63 degrees, respectively). Using linear regression, each minute of continuous fluoroscopy added 18.9 mGy of air kerma (95% confidence interval, 17.6-20.2 mGy), and each DSA series added 21.1 mGy of air kerma (95% confidence interval, 17.9-24.3 mGy). Body mass index and lateral angulation were significantly associated with increased air kerma (P < .001).

CONCLUSIONS

Cannulation of target vessels and bridging stent deployment are the steps requiring the highest radiation exposure during FEVAR cases. Optimized operator protection during these steps is mandatory.

The Use of Advanced Three-Dimensional Computed Tomography During Simple and Complex Endovascular Aortic Aneurysm Repairs

BACKGROUND

Endovascular aneurysm repair (EVAR) success depends on imaging technology both in the planning and operative phases. Endovascular repair requires intravenous contrast and radiation exposure to the patient as well as radiation exposure to the operator. Recent developments in imaging technology attempt to merge preoperative imaging with intraoperative imaging to improve the efficiency and accuracy of EVAR. The Cydar 3-dimensional (3D) imaging system combines the preoperative and intraoperative imaging during the operation. We aim to investigate the use of the Cydar 3D imaging system during EVAR compared to conventional methods.

METHODS

Retrospective review of all patients undergoing an EVAR at a single quaternary vascular center from 2019-2023 was collected. This cohort was divided into 2 groups: (1) repair using Cydar 3D imaging or (2) repair without Cydar 3D imaging. Overall, 138 unique patients were identified with 27 operations using Cydar 3D imaging and 111 operations without Cydar 3D imaging. We performed a 1-to-1 propensity score-matched analysis using nearest-neighbor matching for variables including age, case urgency, and if the case was performed in the operative room or interventional radiology room. A match occurred when a patient in the Cydar 3D imaging group had an estimated score within 0.01 standard deviations of a patient in the control group. From this, we paired 27 from each cohort for a total of 54 patients. Demographic data included length of stay in days, contrast volume (mL), fluoroscopy time (min), procedure length (mins), mortality, and blood loss (mL). Univariate analyses were performed and a P value less than 0.05 was considered statistically significant.

RESULTS

A total of 54 vascular patients were analyzed: 27 without the Cydar 3D imaging and 27 with the Cydar 3D imaging. In the univariate analysis, there was no statistical difference in the average length of stay (6.4 days ± 11.76 vs. 4.1 ± 6.03, P = 0.372), aneurysm size (5.9 ± 1.4 vs. 5.9 ± 1.2, P = 0.88), contrast volume in mL (91.3 ± 47.0 vs. 91.1-33.49, P = 9.88), fluoroscopy time in mins (20.2 ± 17.2 vs. 19.5 ± 19.4, P = 0.89), procedure length (299.3 ± 177.9 vs. 353 ± 191.98, P = 0.279), and blood loss in mL (513.8 ± 791 vs. 353 ± 191.98, P = 0.594). There was an increase in reintervention for endoleaks in the group with use of Cydar 3D imaging (0 vs. 6, P = 0.043). A subanalysis of patients undergoing physician-modified EVARs did show a 15% reduction in the contrast volume used.

CONCLUSIONS

The use of 3D imaging technology has the potential to increase the safety of EVAR to both patients and operators. In our study, we did not find any difference in standard EVARs; however, there was a contrast use decrease in physician-modified EVARs. Further studies will need to be performed to determine the realized benefit from performing EVARs using this new technology.

Development, Feasibility, and Knowledge Impact of a Massive Open Online Course on Radiation Safety: A Multicentre Prospective Cohort Study

OBJECTIVE

This study reports the development of an innovative, interactive Massive Open Online Course (MOOC) teaching radiation safety principles in the vascular workplace, using stepwise e-learning with multiple choice question tests (MCQs), educational videos, and a serious game. The aim was to study the MOOC impact on radiation safety knowledge and assess its feasibility and acceptability.

METHODS

An international multicentre prospective study included team members active in the hybrid operating room. The MOOC was offered voluntarily via a secure online learning platform. A standardised MCQ test (15 questions) assessed radiation safety knowledge pre- and post-course (range 0 - 100%). Acceptability and feasibility were tested via the previously validated, Evaluating e-learning system success (EESS) model, using five point Likert scales.

RESULTS

In eight centres across four countries, 150 of 203 invited endovascular team members consented. Over a seven week study period, surgeons (28%, including vascular surgery trainees and consultants), nurses (27%, including scrub, circulating and anaesthetic nurses), anaesthetists (43%, including trainees and consultants), and radiographers (3%) participated. Of those, 67% completed the course. The average radiation knowledge improved by 22.8% (95% CI 19.5 - 26.0%; p < .001) after MOOC completion, from 48% to 71% (standard deviation [SD] 14 and 15% respectively), requiring a mean time investment of 169 minutes (SD 89 minutes). In centres with a radiographer, mean knowledge gain after MOOC completion was significantly smaller (14%, SD 19% vs. 24%, SD 16%, p = .036). The course was deemed feasible and acceptable according to the EESS model with a total mean score of 3.68/5.

CONCLUSION

This newly developed, multimodal MOOC was deemed feasible and effective across multiple international centres. The MOOC significantly contributes to radiation safety education of the entire endovascular team, improving radiation safety knowledge. The course may optimise workplace radiation safety behaviour and therefore enhance team and patient safety.

Intraoperative Staff Radiation Exposure During Aortic Endovascular Procedures

BACKGROUND

The risk of radiation exposure in the surgical operating room (OR) and/or catheterization laboratory is now well established. Complex endovascular procedures often require multiple approaches and different positioning of the staff members around the patient, potentially increasing the levels of radiations exposure. Our goal was to evaluate the levels of radiation exposure of the members of the staff during endovascular aortic procedures in order to propose radioprotection optimization.

METHODS

We included 41 aortic endovascular procedures out of 114 procedures performed between January 12, 2014, and August 31, 2015, including 24 standard endovascular aortic aneurysm repair (EVAR), 7 EVAR with iliac branch (EVARib), 8 complex fenestrated/branched EVAR (F/B EVAR), and 2 thoracic EVAR (TEVAR). Procedures were performed in an OR equipped with a carbon fiber table and a mobile fluoroscopy C-arm. We collected the usual dosimetry data given by the C-arm as well as the patient's peak skin dose (PSD). In all staff members, radiation exposure was measured with thermoluminescent chip dosimeters placed on both temples, on posterior sides of both hands, and on both lower legs.

RESULTS

PSD levels were low for EVAR because 24 patients had values below the reading threshold. PSD significantly increased with more complex procedures. Main operator (MO) received the higher level of irradiation on whole body, hands, and ankles. Eye lenses irradiation was higher on both assistant operators (AOs). Other members received low levels of irradiation. We found a high ranges of radiation exposure with a high risk of exposure for the AO, mainly for F/B EVAR and EVARib.

CONCLUSIONS

Even if all personal protections are used, staff positioning is a major point that must be considered. If MO is supposed to be the most exposed to X-rays, specific conditions of positioning of the AO may be at risk of exposure.

Addressing Barriers to Entry and Retention of Women in Interventional Vascular Specialties With Proposed Solutions: A Scientific Statement From the American Heart Association

Representation of women in interventional vascular fields (interventional cardiology, interventional radiology, and vascular surgery) lags behind that in other specialties. With women representing half of all medical school graduates, encouraging parity of women in these fields needs to start in medical school. Barriers to pursuing careers in vascular intervention include insufficient exposure during core clerkships, early mentorship, visibility of women in the field, length of training, lifestyle considerations, work culture and environment, and concerns about radiation exposure. This scientific statement highlights potential solutions for both the real and perceived barriers that women may face in pursuing careers in vascular intervention, including streamlining of training (as both interventional radiology and vascular surgery have done with a resultant increase in percentage of women trainees), standardization of institutional promotion of women in leadership, and professional and industry partnerships for the retention and advancement of women.

Underestimation of Occupational Radiation Exposure During Endovascular Abdominal Aortic Aneurysm Repair

ABSTRACT

During interventional procedures of endovascular abdominal aortic aneurysm repair (EVAR), the dosimeter was conventionally placed on chest facing toward the surgical table, instead of the main source of scatter radiation. Purpose of this study is to evaluate the underestimation of occupational radiation exposure. Phantom experiments were performed in a hybrid operating room equipped with an interventional angiography system. Electric personal dosimeters were placed at the level of eyes, chest, abdomen, and gonad of three positions, representing the principal operator (PO), assistant operator (AO), and sterile nurse (SN). Personal dose equivalent was measured with two different orientations of radiation detection, facing the table and facing the phantom, respectively. In addition to fluoroscopy, the dose produced by digital subtraction angiography was also measured to estimate the radiation exposure of routine EVAR. In this study, staff doses of 26 EVAR cases were also collected in our hospital to correlate the estimated dose. Our results show that the facing-phantom dose normalized by dose area product of patient is significantly higher than the facing-table dose when the latter is regularly seen in clinical practice. This underestimation could be even worse at a more distant position (e.g., AO and SN) as the incident angle of scatter radiation is larger. Besides, the estimated dose is highly correlated with the on-site measured dose (R 2 ~ 0.8) at chest and gonad of the PO.

Patients' Radiation Exposure During Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

To investigate associations between patient characteristics, intraprocedural complexity factors, and radiation exposure to patients during endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

Elective standard EVAR procedures between January 2015 and December 2020 were retrospectively analyzed. Patient characteristics and intraprocedural data (i.e., type of device, endograft configuration, additional procedures, and contralateral gate cannulation time [CGCT]) were collected. Dose area product (DAP) and fluoroscopy time were considered as measurements of radiation exposure. Furthermore, effective dose (ED) and doses to internal organs were calculated using PCXMC 2.0 software. Descriptive statistics, univariable, and multivariable linear regression were applied to investigate predictors of increased radiation exposure.

RESULTS

The 99 patients were mostly male (90.9%) with a mean age of 74 ± 7 years. EVAR indications were most frequently abdominal aortic aneurysm (93.9%), penetrating aortic ulceration (2.0%), focal dissection (2.0%), or subacute rupture of infrarenal abdominal aortic aneurysm (2.0%). Median fluoroscopy time was 19.6 minutes (interquartile range [IQR], 14.1-29.4) and median DAP was 86,311 mGy cm2 (IQR, 60,160-130,385). Median ED was 23.2 mSv (IQR, 17.0-34.8) for 93 patients (93.9%). DAP and ED were positively correlated with body mass index (BMI) and CGCT. Kidneys, small intestine, active bone marrow, colon, and stomach were the organs that received the highest equivalent doses during EVAR. Higher DAP and ED values were observed using the Excluder endograft, other bi- and tri-modular endografts, and EVAR with ≥2 additional procedures. Multivariable linear regression analysis revealed that BMI, ≥2 additional procedures during EVAR, and CGCT were independent positive predictors of DAP and ED levels after accounting for endograft type.

CONCLUSIONS

Patient-related and procedure-related factors such as BMI, ≥2 additional procedures during EVAR, and CGCT resulted predictors of radiation exposure for patients undergoing EVAR, as quantified by higher DAP and ED levels. The main intraprocedural factor that increased radiation exposure was CGCT. These data can be of importance for better managing radiation exposure during EVAR.

Overhead arm support reduces radiation exposure during complex endovascular aortic repair

BACKGROUND

Complex endovascular aortic surgery has been associated with increased fluoroscopic radiation exposure. The radiation dosage necessary for visualization is dependent on the amount of tissue penetration required. Elevation of a patient's arms above their head during endovascular surgery could improve visualization by removing the arms from the field of view. Furthermore, it might reduce the radiation dose required. In the present study, we sought to determine the effect of arm elevation on radiation exposure during endovascular treatment of thoracoabdominal aneurysms.

METHODS

All patients enrolled in a single-institution, physician-sponsored investigational device exemption study for endovascular treatment of thoracoabdominal aneurysms (fenestrated/branched endovascular aortic repair [F/BEVAR]) from 2012 to 2022 were assessed. The first 30 patients treated were excluded to account for the learning curve required with treatment. Patients treated after December 2020 were positioned with their arms elevated above their head using an overhead arm support (OAS). These patients were compared with those who had undergone F/BEVAR before the practice change. The radiation dose, fluoroscopy time, and contrast volume used were compared. A subgroup analysis was performed to assess the effect for patients with brachial access.

RESULTS

A total of 145 patients were included in the present study, of whom 43 (30%) had undergone F/BEVAR with their arms supported overhead. No differences were identified in age, body mass index, aneurysm size, or prior aortic intervention between the groups with and without the use of the OAS. A history of dissection (23% vs 7.8%; P = .01) was more frequent for the patients treated with their arms elevated. Arm elevation was associated with a significant reduction in the mean radiation exposure (2261 vs 3100 mGy; P = .01). No differences were observed in the fluoroscopy time or contrast volume used between the two groups. In addition, no patient experienced palsy of the brachial plexus. Of the 145 patients, 55 (38%) had required brachial arterial access, limiting their ability to elevate both arms. In the subgroup analysis, the patients without brachial access continued to show a significant reduction in radiation exposure with arm elevation (2159 vs 3179 mGy; P < .01).

CONCLUSIONS

Elevation of a patient's arms above their head using an OAS during F/BEVAR offered a low-cost, simple strategy that resulted in a 30% reduction in radiation exposure without added complications. This technique improved visualization and reduced radiation exposure for patients and physicians and should be included in abdominal aortic and visceral procedures work to improve patient and surgeon safety.

Modified design of x-ray protective clothing to enhance radiation protection for interventional radiologists

BACKGROUND

In interventional radiology procedures, the operator typically stands on the right side of the patient's right thigh to manipulate devices through the femoral sheath. Because the standard x-ray protective clothing is designed as sleeveless and scatter radiations from the patient are mainly incident from the left-anterior direction to the operator, the arm hole of the clothing may be a significant unprotected area, contributing to an increase in the operator's organ doses and effective dose.

PURPOSE

This study aimed to compare the organ doses and effective dose received by the interventional radiologist when wearing the standard x-ray protective clothing and when wearing the modified clothing with an additional shoulder guard.

METHODS

The experimental setup aimed to simulate actual clinical practice in interventional radiology. The patient phantom was located at the beam center to generate scatter radiation. An adult female anthropomorphic phantom loaded with 126 nanoDots (Landauer Inc., Glenwood, IL) was used to measure organ and effective doses to the operator. The standard wrap-around type x-ray protective clothing offered 0.25-mm lead-equivalent protection, and the frontal overlap area offered 0.50-mm lead-equivalent protection. The shoulder guard was custom-made with a material providing x-ray protection equivalent to lead of 0.50 mm thickness. The organ and effective doses were compared between the operator wearing the standard protective clothing and the one wearing the modified clothing with a shoulder guard.

RESULTS

After adding the shoulder guard, doses to the lungs, bone marrow, and esophagus decreased by 81.9%, 58.6%, and 58.7%, respectively, and the effective dose to the operator decreased by 47.7%.

CONCLUSIONS

Widespread use of modified x-ray protective clothing with shoulder guards can significantly decrease the overall occupational radiation risk in interventional radiology.

A comparison of patient dose and occupational eye dose to the operator and nursing staff during transcatheter cardiac and endovascular procedures

The number and complexity of transcatheter procedures continue to increase, raising concerns regarding radiation exposure to patients and staff. Procedures such as transaortic valve implantations (TAVI) have led to cardiologists adopting higher dose techniques, such as digital subtraction angiography (DSA). This study compared the estimated patient and occupational eye dose during coronary angiography (CA), percutaneous coronary intervention (PCI), TAVI workups (TWU), TAVI, endovascular aneurysm repairs (EVAR), and other peripheral diagnostic (VD) and interventional (VI) vascular procedures. A quantitative analysis was performed on patient dose during 299 endovascular and 1498 cardiac procedures. Occupational dose was measured for the cardiologists (n = 24), vascular surgeons (n = 3), scrub (n = 32) and circulator nurses (n = 35). TAVI and EVAR were associated with the highest average dose for all staff, and significantly higher patient dose area product, probably attributable to the use of DSA. Scrub nurses were exposed to higher average doses than the operator and scout nurse during CA, VD and VI. Circulating nurses had the highest average levels of exposure during TAVI. This study has demonstrated that EVAR and TAVI have similar levels of occupational and patient dose, with a notable increase in circulator dose during TAVI. The use of DSA during cardiac procedures is associated with an increase in patient and staff dose, and cardiologists should evaluate whether DSA is necessary. Scrub nurses may be exposed to higher levels of occupational dose than the operator.

Operator Lower Leg Radiation Dose during Fluoroscopically Guided Interventions is Effectively Reduced by Wearing Lead-Equivalent Leg Wraps

BACKGROUND

The intensity of radiation scatter that emanates from the X-ray beam during fluoroscopically guided interventions is greater below the fluoroscopy table than above. Yet interventionalists' lower legs are typically unshielded and table skirts are often positioned incorrectly. We sought to characterize the efficacy of the leg protector wraps (Leg Wraps, Burlington Medical Inc.) in reducing the radiation dose to the operator's lower leg during fenestrated and branched endovascular aneurysm repair (F-BEVAR).

METHODS

A prospective cohort study was performed evaluating the lower leg radiation dose reduction of one vascular surgeon during F/BEVAR using antimony/bismuth Enviro-Lite leg wraps (0.35 mm lead equivalency, 99.7% attenuation at 50 kVp; Burlington Medical, Hampton Roads, Virginia). Optically Stimulated Luminescence nanoDot detectors (microSTARii System, LANDAUER, Inc., Glenwood, Illinois) were placed over and under the left leg wrap at the anterior tibial tuberosity position to compare operator leg dose with and without this additional protection. The table-mounted lead skirt was used consistently in all cases. The nanoDot detectors were cross-calibrated with a survey meter (RaySafe X2 survey sensor, Fluke Biomedical, Cleveland, Ohio) by measuring scattered radiation at a position equivalent to an operator's mid-tibia while performing digital acquisitions of a 25-cm thick, 30 cm × 30 cm acrylic phantom with a Philips FD20 fluoroscope (Philips Healthcare, Best, The Netherlands) with the table skirt removed. The measured radiation doses were converted to a Hp (0.07) skin dose, assuming an RQR6 beam spectrum (IEC-61267). Paired Wilcoxon test was performed to identify significant attenuation of radiation exposure.

RESULTS

Leg dose measurements from 40 F-BEVARs were analyzed. The patients had a median (interquartile range) body mass index of 27 (24-32) kg/m². Median procedure reference air kerma was 1,100 (728-1,601) mGy, kerma-area product was 127 (73-184) Gycm², and fluoroscopy time was 69 (54-86) min. The median skin dose H_p (0.07) over the leg wraps (n = 40) was 54.2 (24-100) μSv and under the leg wraps (n = 40) was 2.7 μSv (1.0-5.8). The leg wraps attenuated the radiation dose by 95% (89-98%) (P < 0.001). The unprotected, H_p (0.07) per kerma-area product was determined to be 0.38 (0.30-0.55) μSv/Gycm².

CONCLUSIONS

The 0.35-mm lead-equivalent leg wraps significantly decreased scattered radiation to the lower leg during F-BEVAR. Protective leg wraps should be recommended to operators performing complex fluoroscopically guided procedures.

Cloud-based fusion imaging improves operative metrics during fenestrated endovascular aneurysm repair

OBJECTIVE

Endovascular treatment of complex aortic pathology has been associated with increases in procedural-related metrics, including the operative time and radiation exposure. Three-dimensional fusion imaging technology has decreased the radiation dose and iodinated contrast use during endovascular aneurysm repair. The aim of the present study was to report our institutional experience with the use of a cloud-based fusion imaging platform during fenestrated endovascular aneurysm repair (FEVAR).

METHODS

A retrospective review of a prospectively maintained aortic database was performed to identify all patients who had undergone FEVAR with commercially available devices (Zenith Fenestrated; Cook Medical Inc, Bloomington, IN) between 2013 and 2020 and all endovascular aneurysm repairs performed using Cydar EV Intelligent Maps (Cydar Medical, Cambridge, UK). The Cydar EV cohort was reviewed further to select all FEVARs performed with overlay map guidance. The patient demographic, clinical, and procedure metrics were analyzed, with a comparative analysis of FEVAR performed without and with the Cydar EV imaging platform. Patients were excluded from comparative analysis if the data were incomplete in the dataset or they had a documented history of prior open or endovascular abdominal aortic aneurysm repair.

RESULTS

During the 7-year study period, 191 FEVARs had been performed. The Cydar EV imaging platform was implemented in 2018 and used in 124 complex endovascular aneurysm repairs, including 69 consecutive FEVARs. A complete dataset was available for 137 FEVARs. With exclusion to select for de novo FEVAR, a comparative analysis was performed of 53 FEVAR without and 63 with Cydar EV imaging guidance. The cohorts were similar in patient demographics, medical comorbidities, and aortic aneurysm characteristics. No significant difference was noted between the two groups for major adverse postoperative events, length of stay, or length of intensive care unit stay. The use of Cydar EV resulted in nonsignificant decreases in the mean fluoroscopy time (69.3 ± 28 minutes vs 66.2 ± 33 minutes; P = .598) and operative time (204.4 ± 64 minutes vs 186 ± 105 minutes; P = .278). A statistically significant decrease was found in the iodinated contrast volume (105 ± 44 mL vs 83 ± 32 mL; P = .005), patient radiation exposure using the dose area product (1,049,841 mGy/cm² vs 630,990 mGy/cm²; P < .001) and cumulative air kerma levels (4518 mGy vs 3084 mGy; P = .02) for patients undergoing FEVAR with Cydar EV guidance.

CONCLUSIONS

At our aortic center, we have observed a trend toward shorter operative times and significant reductions in both iodinated contrast use and radiation exposure during FEVAR using the Cydar EV intelligent maps. Intelligent map guidance improved the efficiency of complex endovascular aneurysm repair, providing a safer intervention for both patient and practitioner.

Outcomes of upper access with surgical exposure of the axillary artery in fenestrated and branched endovascular aneurysm repair

OBJECTIVES

This study aims to assess the safety of upper access with surgical exposure of the axillary artery in fenestrated and branched endovascular aneurysm repair (F/B-EVAR), evaluating neurologic and local complications as well as reinterventions associated with this technique.

METHODS

All patients undergoing a F/B-EVAR procedure with surgical exposure of the axillary artery between January 2010 and March 2020 were included in this retrospective single-centre study. Endpoints were neurological and access-related complications and reinterventions related to the upper extremity access. Complications related to the technique included stroke/transient ischaemic attack, wound infection, peripheral nerve injury and arterial complications.

RESULTS

264 patients (192 male, mean age 70 ± 7 years) were included. Upper access was performed over the left axillary artery in 257 (97%) of the cases, and over the right axillary artery in the remaining seven cases. Six (2,2%) patients had early complications related to the arterial access: four with postoperative bleeding and two with acute arm ischaemia. Two patients with postoperative bleeding and both patients with ischaemic complications required reintervention. One of these patients with arm ischaemia died five weeks after the reintervention due to sepsis complications related to patch infection. Sixteen (6%) patients presented transient arm paraesthesia or sensory neurologic deficit postoperatively. The symptoms completely recovered in all cases with no residual deficits. Perioperative ischaemic stroke occurred in three (1%) patients (two minor, one major). No other access related complications were recorded during follow up in any of the patients with no cases of late stenosis/occlusion.

CONCLUSIONS

Upper access with surgical exposure of the axillary artery is a safe method for antegrade catheterization of fenestrations and branches in complex endovascular aneurysm repair.

Occupational doses in interventional angiography after radiological protection training and use of a real-time direct display dosimeter

Vascular x-ray guided interventions are complex and may result in high occupational doses to ionising radiation if staff do not take appropriate actions to minimise their exposure. In this prospective intervention study, ten staff members wore an extra personal dosimeter on the upper body above their regular protective clothing during four consecutive periods. Between each period either additional practical radiological protection training was given or a real-time direct display dosimeter were provided to the staff. Each staff's personal dose equivalent, Hp(10) normalised to the total air kerma-area product for the procedures where each staff were involved, KAPt, was used as the dependent variable. A focus-group interview with the staff were performed about the usefulness of the training and real-time dose rate display system. Our aim was to investigate if the interventions (practical training or real-time dose rate display) did affect the staff doses in the short and long term (five months later). Significant (p < 0.05) reductions of staff doses Hp(10)/KAPt were found after practical radiological protection training, but not after using real-time dose rate displays. Significant reductions were maintained after five months without additional interventions. The results from the focus-group interview indicated that making radiation 'visible', during practical training and usage of real-time direct display dosimeter, made it easier to understand how to act to lower occupational doses.

Fluoroscopically-guided interventions with radiation doses exceeding 5000 mGy reference point air kerma: a dosimetric analysis of 89,549 interventional radiology, neurointerventional radiology, vascular surgery, and neurosurgery encounters

Purpose

To quantify and categorize fluoroscopically-guided procedures with radiation doses exceeding 5000 mGy reference point air kerma (K_a,r). K_a,r > 5000 mGy has been defined as a “significant radiation dose” by the Society of Interventional Radiology. Identification and analysis of interventions with high radiation doses has the potential to reduce radiation-induced injuries.

Materials and methods

Radiation dose data from a dose monitoring system for 19 interventional suites and 89,549 consecutive patient encounters from January 1, 2013 to August 1, 2019 at a single academic institution were reviewed. All patient encounters with K_a,r > 5000 mGy were included. All other encounters were excluded (n = 89,289). Patient demographics, medical specialty, intervention type, fluoroscopy time (minutes), dose area product (mGy·cm²), and K_a,r (mGy) were evaluated.

Results

There were 260 (0.3%) fluoroscopically-guided procedures with K_a,r > 5000 mGy. Of the 260 procedures which exceeded 5000 mGy, neurosurgery performed 81 (30.5%) procedures, followed by interventional radiology (n = 75; 28.2%), neurointerventional radiology (n = 55; 20.7%), and vascular surgery (n = 49; 18.4%). The procedures associated with the highest K_a,r were venous stent reconstruction performed by interventional radiology, arteriovenous malformation embolization performed by neurointerventional radiology, spinal hardware fixation by neurosurgery, and arterial interventions performed by vascular surgery. Neurointerventional radiology had the highest mean K_a,r (7,799 mGy), followed by neurosurgery (7452 mGy), vascular surgery (6849 mGy), and interventional radiology (6109 mGy). The mean K_a,r for interventional radiology performed procedures exceeding 5000 mGy was significantly lower than that for neurointerventional radiology, neurosurgery, and vascular surgery.

Conclusions

Fluoroscopically-guided procedures with radiation dose exceeding 5000 mGy reference point air kerma are uncommon. The results of this study demonstrate that a large proportion of cases exceeding 5000 mGy were performed by non-radiologists, who likely do not receive the same training in radiation physics, radiation biology, and dose reduction techniques as radiologists.

Comparison of Cerebral Embolic Events Between Right and Left Upper Extremity Access During Fenestrated/Branched Endovascular Aortic Repair

Purpose:

To evaluate the incidence and outcomes of cerebral embolic events when using right (RUE) vs left upper extremity (LUE) access for fenestrated/branched endovascular aneurysm repair (f/bEVAR).

Materials and Methods:

A retrospective review was conducted of 290 consecutive patients enrolled in a physician-sponsored Investigational Device Exemption study to evaluate f/bEVAR between 2013 and 2018. Of these, 270 patients (93%) had an upper extremity access with 12-F sheaths, including 205 patients (mean age 75±8 years; 147 men) with LUE and 65 patients (mean age 73±8 years; 42 men) with RUE access. Outcome measures were technical success, procedural metrics, major adverse events (MAEs), any stroke or transient ischemic attack (TIA), and mortality.

Results:

Technical success was higher (p=0.04) for LUE (99.6%) vs RUE access (98.4%). Patients treated via RUE access more often had extent I-III thoracoabdominal aortic aneurysms (57% vs 39%, p=0.03). Procedural metrics were similar for LUE vs RUE sides, including endovascular time (255±80 vs 246±83 minutes, respectively; p=0.23), fluoroscopy time (84±32 vs 90±35 minutes, respectively; p=0.80), and contrast volume (156±57 vs 153±56 mL, respectively; p=0.82). Total radiation exposure was significantly higher for LUE vs RUE access (2463±1912 vs 1757±1494 mGy, respectively; p=0.02). There were 2 deaths (1%) at 30 days or during hospital admission, both unrelated to access site complications. MAEs occurred in 32% of patients who had LUE and 26% of those who had RUE access (p=0.44). Five patients (2%) had embolic stroke and none had TIA. Embolic strokes were ipsilateral to the access side in 4 patients and affected the posterior circulation in 3. Two patients (1%) had hemorrhagic strokes. The incidence of stroke was 3% for LUE and 2% for RUE access (p>0.99).

Conclusion:

Fenestrated/branched stent-graft repair was associated with low rates of cerebral embolic events and no significant difference between the right vs left upper extremity approach.

Editor's Choice - Comprehensive Literature Review of Radiation Levels During Endovascular Aortic Repair in Cathlabs and Operating Theatres

OBJECTIVE

Occupational exposure is a growing concern among the endovascular specialist community. Several types of imaging equipment are available, such as mobile C arms or hybrid rooms, and some have been shown to deliver higher levels of radiation. A literature review was conducted to identify studies reporting dose data during standard (EVAR) and complex abdominal aortic endovascular repair (fenestrated/branched EVAR [F/BEVAR]).

METHODS

A search of the MEDLINE and the Cochrane databases was performed by two independent investigators using the medical subject heading terms "aortic aneurysms", "radiation", and "humans" over a search period of 10 years. Studies with full text available in English and reporting radiation data independently from the imaging equipment type were included. Experimental studies were excluded.

RESULTS

The lowest dose-area product levels during EVAR and F/BEVAR were identified in hybrid rooms, while the highest were with fixed systems. When adherence to the as low as reasonably achievable principles was stipulated by the authors, dose reports tended to be among the lowest. Several studies, especially of F/BEVAR, report concerning levels of radiation for both patients and staff.

CONCLUSION

Modern imaging equipment type, team involvement with radiation management, and the support of recent imaging technologies such as fusion help to reduce the dose delivered during standard and complex EVAR. Investment in modern imaging technology should be considered in every centre providing endovascular management of aortic aneurysms.

Dual fluoroscopy with live-image digital zooming significantly reduces patient and operating staff radiation during fenestrated-branched endovascular aortic aneurysm repair

OBJECTIVE

Fenestrated-branched endovascular aneurysm repair (F/B-EVAR) is a complex procedure that generates high radiation doses. Magnification aids in vessel cannulation but increases radiation. The aim of the study was to compare radiation doses to patients and operating room staff from two fluoroscopy techniques, standard magnification vs dual fluoroscopy with live-image digital zooming during F/B-EVAR.

METHODS

An observational, prospective, single-center study of F/B-EVAR procedures using Philips Allura XperFD20 equipment (Philips Healthcare, Amsterdam, The Netherlands) was performed during a 42-month period. Intravascular ultrasound, three-dimensional fusion, and extreme collimation were used in all procedures. Intraoperative live-image processing was performed with two imaging systems: standard magnification in 123 patients (81%) and dual fluoroscopy with live-image digital zooming in 28 patients (18%). In the latter, the live "processed" zoomed images are displayed on examination displays and live images are displayed on reference displays. The reference air kerma was collected for each case and represents patient dose. Operating staff personal dosimetry was collected using the DoseAware system (Philips Healthcare). Patient and staff radiation doses were compared using nonparametric tests.

RESULTS

Mean age was 71.6 ± 11.4 years. The median body mass index was 27 kg/m² (interquartile range [IQR], 24.4-30.6 kg/m²) and was the same for both groups. Procedures performed with dual fluoroscopy with digital zooming demonstrated significantly lower median patient (1382 mGy [IQR, 999-2045 mGy] vs 2458 mGy [IQR, 1706-3767 mGy]; P < .01) and primary operator radiation doses (101 μSv [IQR, 34-235 μSv] vs 266 μSv [IQR, 104-583 μSv]; P < .01) compared with standard magnification. Similar significantly reduced radiation doses were recorded for first assistant, scrub nurse, and anesthesia staff in procedures performed with dual fluoroscopy. According to device design, procedures performed with four-fenestration/branch devices generated higher operator radiation doses (262 μSv [IQR, 116.5-572 μSv] vs 171 μSv [IQR, 44-325 μSv]; P < .01) compared with procedures with three or fewer fenestration/branches. Among the most complex design (four-vessel), operator radiation dose was significantly lower with digital zooming compared with standard magnification (128.5 μSv [IQR, 70.5-296 μSv] vs 309 μSv [IQR, 150-611 μSv]; P = .01).

CONCLUSIONS

Current radiation doses to patients and operating personnel are within acceptable limits; however, dual fluoroscopy with live-image digital zooming results in dramatically lower radiation doses compared with the standard image processing with dose-dependent magnification. Operator radiation doses were reduced in half during procedures performed with more complex device designs when digital zooming was used.

Percutaneous AXillary Artery (PAXA) Access at the First Segment During Fenestrated and Branched Endovascular Aortic Procedures

OBJECTIVE

The aim of this study was to assess the feasibility and safety of percutaneous axillary access with vessel closure device closure after puncturing the first segment during endovascular treatment of complex aneurysms with fenestrated and branched endografts (F/BEVAR).

METHODS

The PAXA (Percutaneous AXillary Access) study is a physician initiated, single centre, ambispective, non-randomised study (clinicaltrials.gov: NCT03223311). The primary endpoint was the closure success rate defined as the absence of any vascular injury to achieve haemostasis at the puncture site, requiring any treatment other than manual compression or adjunctive endovascular ballooning. The secondary endpoints were minor access complications, cerebrovascular complication rate, short term access vessel patency, and study cohort anatomical evaluation of the axillary artery.

RESULTS

Sixty-four patients required an upper extremity access during F/BEVAR procedure during study period (November 2016 to July 2019) and were screened for the PAXA study: 59 patients (47 males; median age: 75 years, IQR 69-78) met the study inclusion criteria and were enrolled (one patient had bilateral access). Closure success was obtained in 54 cases (90%) with no open conversion required: five patients received a bare or covered stenting to the AXA and in one patient mechanical failure of the delivery system was recorded. No 30 day permanent peripheral nerve injuries and two non-ipsilateral ischaemic strokes (3.4%) were recorded. Seven patients (12%) had access haematomas managed conservatively associated with closure failure (p = .002), oral anticoagulants therapy (p = .005) and procedure length (p = .028). At short term follow up (6 months), no late complications were observed, and all access vessels were patent.

CONCLUSION

PAXA on the first segment using a large sheath (10-16F) is technically feasible, relatively safe with no need for open conversion but it may require access related secondary endovascular procedures. Further prospective studies are needed to modify the device instruction for use and to put the procedure on label.

Correlations Between Branch Vessel Catheterization and Procedural Complexity in Fenestrated and Branched Endovascular Aneurysm Repair

Introduction:

The use of fenestrated and branched endovascular technologies in complex aortic aneurysm repair (F/BEVAR) is increasing, with a trend toward using longer sealing zones and incorporating more target vessels. Successful aneurysm exclusion and prevention of long-term treatment failure need to be balanced against the increased complexity of more extensive procedures. The aim of this study was to analyze relationships between the number of catheterized vessels and multiple operative variables as a means for evaluating procedural complexity.

Methods:

Operative data from consecutive F/BEVAR procedures performed at a single center from 2012 to 2015 were analyzed. An equal number of EVAR procedures, randomly selected, from this period were also analyzed. Only intact aneurysms were included. Complex aneurysms were grouped based on the required number of target vessel catheterization. Ten procedural variables, categorized as perioperative, postoperative, and radiologic-related, were compared. Pearson correlation analysis and regression analysis were performed. The correlation coefficients, r, were classified using Cohen boundaries, r ≥ 0.5 indicating a strong relationship.

Results:

There were 63 EVAR, 40 FEVAR, and 22 BEVAR procedures. There was no significant difference in patient comorbidities between conventional EVAR and complex procedure groups. The complex procedures included 23 two-vessel, 20 three-vessel, and 19 four-vessel catheterizations. Strong linear relationships between the number of branch vessel catheterizations and the following variables were identified: accumulated skin dose ( r = .504), contrast volume ( r = .652), fluoroscopy duration ( r = .598), number of angiography series ( r = .650), anesthesiology duration ( r = .742), procedure duration ( r = .554), and total length of stay ( r = .533).

Conclusion:

The complexity of FEVAR and BEVAR procedures reveals strong correlations between multiple peri- and postoperative variables. These exposures and risks should be borne in mind when considering treatment of complex abdominal aortic aneurysms as well as long-term clinical outcomes.

Patient and operating room staff radiation dose during fenestrated/branched endovascular aneurysm repair using premanufactured devices

INTRODUCTION

Fenestrated endovascular aneurysm repair (FEVAR) is the highest radiation dose procedure performed by vascular surgeons. We sought to characterize the radiation dose to patients and staff during FEVAR procedures with different premanufactured devices.

METHODS

A single-center prospective study of FEVARs was performed over 24 months. Three FEVAR devices were included: off-the-shelf (OTS; t-Branch, p-Branch), Zenith Fenestrated (ZFen), and investigational custom-made devices (CMDs). Radiation doses to the surgeon, trainee, anesthesiologist, and scrub/circulating nurses were measured using a personal dosimetry system (DoseAware, Philips Healthcare, Amsterdam, The Netherlands). Procedure type, patient body mass index (BMI), reference air kerma (RAK), and kerma area product (KAP) were recorded. RAK and KAP were corrected for BMI based on an exponential fit of fluoroscopy dose rate and the dose per radiographic frame. Operator dose was corrected for BMI by the ratio of corrected to actual KAP. A one-sided Wilcox rank-sum test was used to compare personnel radiation doses, RAKs, and KAPs between procedure types. Statistical significance was set at P ≤ .05.

RESULTS

There were 80 FEVARs performed by a single surgeon on a Philips Allura XperFD20 fluoroscopy system equipped with Clarity technology. Average BMI was 27 kg/m². Sixty CMDs (36 four-, 21 three-, and 3 two-vessel fenestrations), 11 ZFens (8 three- and 3 two-vessel fenestrations), and 9 OTS devices (4 p-Branch, 5 t-Branch) were included. ZFens had significantly lower patient (1800 mGy vs 2950 mGy; P = .004), operator (120 μSv vs 370 μSv; P = .004), assistant (60 μSv vs 210 μSv; P = .003), circulator (10 μSv vs 30 μSv; P = .049), and scrub nurse dose (10 μSv vs 40 μSv; P = .02) compared with CMDs. OTS devices had significantly lower operator (220 μSv vs 370 μSv; P = .04), assistant (110 μSv vs 210 μSv; P = .02), and circulator doses (4 μSv vs 30 μSv; P = .001) compared with CMDs. Four-vessel fenestrated devices had significantly higher patient dose (3020 mGy) compared with three-vessel FEVARs (2670 mGy; P = .03) and two-vessel FEVARs (1600 mGy; P = .0007), and significantly higher operator dose (440 μSv) compared with three-vessel FEVARs (170 μSv; P = .0005). Patient dose was lowest with ZFens. Operating room personnel dose was lower with ZFens and OTS devices compared with CMDs. Four-vessel fenestrations required significantly more radiation compared with those involving three-vessel fenestrations; however, the dose increase was only 12% and should not preclude operators from extending coverage, if anatomically required.

CONCLUSIONS

Overall, patient and personnel radiation doses during FEVAR with all devices were within acceptable limits and lower in our series than previously reported.

Physician and Patient Radiation Exposure During Endovascular Procedures

OPINION STATEMENT

Endovascular procedures expose both patients and physicians to fluoroscopic ionizing radiation that carries a dose-dependent risk of acute toxicity and a small, but demonstrable, long-term risk of malignancy due to resultant genetic mutations. Exposure doses vary widely based upon patient-related factors including body size and anatomic complexity, operator technique, procedure type (diagnostic vs. therapeutic), vascular bed imaged, and imaging equipment employed. Effective dosage may vary as much as 200-fold for physicians and 20-fold for patients depending upon the procedure: for example, complex aortic interventions with branched graft devices may convey mean effective doses of more than 0.4 mSv for physicians and 100 mSv for patients, whereas distal, small-vessel angiography may entail mean effective doses of less than 0.002 mSv for physicians and 5 mSv for patients. Particular attention is given to physicians' ocular exposure, which may cause cataract development, and to hand exposure, which is significantly higher than total body exposure when operators work near the x-ray beam. Given the risks of radiation exposure, numerous strategies have been developed to reduce both physician and patient doses. These measures include physician education about dose-reducing imaging techniques, development of low-dose imaging equipment, introduction of new radiation shielding drapes and caps, and real-time dose monitoring. Here, we review physician and patient effective doses of radiation by procedure type as reported in the literature and present recent data regarding dose-reduction strategies.

Computer-assisted study of the axial orientation and distances between renovisceral arteries ostia

PURPOSE

Endovascular navigation in aortic, renal and visceral procedures are based on precise knowledge of arterial anatomy. Our aim was to define the anatomical localization of the ostia of renovisceral arteries and their distribution to establish anatomical landmarks for endovascular catheterization.

METHODS

Computer-assisted measurements performed on 55 CT scans and patients features (age, sex, aortic diameter) were analyzed. p values <0.05 were considered statistically significant.

RESULTS

The mean axial angulation of CeT and the SMA origin was 21.8° ± 10.1° and 9.9° ± 10.5°, respectively. The ostia were located on the left anterior edge of the aorta in 96 % of cases for the CeT and 73 % for the SMA. CeT and SMA angles followed Gaussian distribution. Left renal artery (LRA) rose at 96° ± 15° and in 67 % of cases on the left posterior edge. The right renal artery (RRA) rose at -62° ± 16.5° and in 98 % of cases on the right anterior edge of the aorta. RRA angle measurements and cranio-caudal RRA-LRA distance measurements did not follow Gaussian distribution. The mean distances between the CeT and the SMA, LRA, and RRA were 16.7 ± 5.0, 30.7 ± 7.9 and 30.5 ± 7.7 mm, respectively. CeT-SMA distance showed correlation with age and aortic diameter (p = 0.03). CeT-LRA distance showed correlation with age (p = 0.04). The mean distance between the renal ostia was 3.75 ± 0.21 mm. The RRA ostium was higher than the LRA ostium in 52 % of cases. RRA and LRA origins were located at the same level in 7 % of cases.

CONCLUSION

Our results illustrate aortic elongation with ageing and high anatomical variability of renal arteries. Our findings are complementary to anatomical features previously published and might contribute to enhance endovascular procedures safety and efficacy for vascular surgeons and interventional radiologists.