Reduction of Occupational Radiation Exposure During Endovascular Treatment of Peripheral Artery Disease Using Radiation Absorbing Drapes.

BACKGROUND: A chronic exposure to low dose radiation, as encountered in endovascular procedures, may impact the health of surgeons and radiologists over a timespan of several months to a lifetime. This study evaluates the feasibility and efficacy of a radiation absorbing sterile drape (RADPAD) to reduce operator exposure during the endovascular treatment of obstructive peripheral artery disease (PAD). METHODS: Between February 2016 and September 2017, patients with PAD who received percutaneous transluminal angioplasty, stent placement, remote endarterectomy, or a combination thereof were included in this nonrandomized study. Patients were equally divided over a study cohort (with RADPAD) and a control cohort (without RADPAD). The unshielded body dose (E) of the staff was measured via electronic dosimeters placed at a chest height of the first operator (FO), second operator (SO), and sterile nurse (SN). A virtual maximum operator (MO) dose was constructed, yielding the highest dose per fluoroscopy run for either of the operators. Simultaneously, the dose area product (DAP) and C-arm settings for each fluoroscopy run were extracted. Staff exposures of the study cohort and control cohort were compared in terms of relative exposure (E/DAP). A secondary analysis involved an analysis of the individual fluoroscopy runs using a multivariate generalized linear mixed effect model. RESULTS: In total, 49 patients were included in this study. The use of RADPAD was technically feasible. Significant reductions of relative exposure were observed when comparing the study cohort with the control cohort. The relative exposure of the FO was reduced with 66.5% (1.82 vs. 0.61 µSv/Gycm2, P < 0.001), the relative exposure of the SO with 68.3% (0.55 vs. 0.17 µSv/Gycm2, P = 0.02), and the relative exposure of the MO with 65.8% (2.06 vs. 0.71 µSv/Gycm2, P < 0.001). Dose levels of SN were too low to draw conclusions under the current sample size. The multivariate generalized linear mixed effect model showed a significant correlation between absolute exposure of the MO and the use of the RADPAD (odds: 0.51, P < 0.001). CONCLUSIONS: Usage of a radiation absorbing drape (RADPAD) during endovascular treatment of PAD results in statistically significant reduction in a relative operator dose while presenting no drawbacks. The use of these drapes is advised in future peripheral endovascular procedures.

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

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

First in Human Clinical Feasibility Study of Endovascular Navigation with Fiber Optic RealShape (FORS) Technology.

OBJECTIVE: Endovascular procedures are conventionally conducted using two dimensional fluoroscopy. A new technology platform, Fiber Optic RealShape (FORS), has recently been introduced allowing real time, three dimensional visualisation of endovascular devices using fiberoptic technology. It functions as an add on to conventional fluoroscopy and may facilitate endovascular procedures. This first in human study assessed the feasibility of FORS in clinical practice. METHODS: A prospective cohort feasibility study was performed between July and December 2018. Patients undergoing (regular or complex) endovascular aortic repair (EVAR) or endovascular peripheral lesion repair (EVPLR) were recruited. FORS guidance was used exclusively during navigational tasks such as target vessel catheterisation or crossing of stenotic lesions. Three types of FORS enabled devices were available: a flexible guidewire, a Cobra-2 catheter, and a Berenstein catheter. Devices were chosen at the physician's discretion and could comprise any combination of FORS and non-FORS devices. The primary study endpoint was technical success of the navigational tasks using FORS enabled devices. Secondary study endpoints were user experience and fluoroscopy time. RESULTS: The study enrolled 22 patients: 14 EVAR and eight EVPLR patients. Owing to a technical issue during start up, the FORS system could not be used in one EVAR. The remaining 21 procedures proceeded without device or technology related complications and involved 66 navigational tasks. In 60 tasks (90.9%), technical success was achieved using at least one FORS enabled device. Users rated FORS based image guidance "better than standard guidance" in 16 of 21 and "equal to standard guidance" in five of 21 procedures. Fluoroscopy time ranged from 0.0 to 52.2 min. Several tasks were completed without or with only minimal X-ray use. CONCLUSION: Real time navigation using FORS technology is safe and feasible in abdominal and peripheral endovascular procedures. FORS has the potential to improve intra-operative image guidance. Comparative studies are needed to assess these benefits and potential radiation reduction.

Feasibility of fresh frozen human cadavers as a research and training model for endovascular image guided interventions.

OBJECTIVE: To describe the feasibility of a fresh frozen human cadaver model for research and training of endovascular image guided procedures in the aorta and lower extremity. METHODS: The cadaver model was constructed in fresh frozen human cadaver torsos and lower extremities. Endovascular access was acquired by inserting a sheath in the femoral artery. The arterial segment of the specimen was restricted by ligation of collateral arteries and, in the torsos, clamping of the contralateral femoral artery and balloon occlusion of the supratruncal aorta. Tap water was administered through the sheath to create sufficient intraluminal pressure to manipulate devices and acquire digital subtraction angiography (DSA). Endovascular cannulation tasks of the visceral arteries (torso) or the peripheral arteries (lower extremities) were performed to assess the vascular patency of the model. Feasibility of this model is based on our institute's experiences throughout the use of six fresh frozen human cadaver torsos and 22 lower extremities. RESULTS: Endovascular simulation in the aortic and peripheral vasculature was achieved using this human cadaver model. Acquisition of DSA images was feasible in both the torsos and the lower extremities. Approximately 84 of the 90 target vessels (93.3%) were patent, the remaining six vessels showed signs of calcified steno-occlusive disease. CONCLUSIONS: Fresh frozen human cadavers provide a feasible simulation model for aortic and peripheral endovascular interventions, and can potentially reduce the need for animal experimentation. This model is suitable for the evaluation of new endovascular devices and techniques or to master endovascular skills.

Procedure and step-based analysis of the occupational radiation dose during endovascular aneurysm repair in the hybrid operating room.

OBJECTIVE: This study measured the cumulative occupational X-ray radiation dose received by support staff during endovascular aortic procedures and during additional intraoperative steps in the hybrid operating room. METHODS: Radiation dose measurements were performed during interventions on 65 patients receiving 90 stent grafts during endovascular aneurysm repair (EVAR), bifurcated EVAR, thoracic EVAR, iliac branched device deployment, aortouni-iliac stenting, and fenestrated/branched EVAR (F/BrEVAR). X-ray imaging was acquired using the Philips Allura FD20 Clarity System (Philips Medical Systems, Best, The Netherlands). The occupational radiation dose (also referred to as the estimated effective dose, E, measured in millisieverts) was measured with the DoseAware Xtend system (Philips Medical Systems) personal dosimeters. E was reported per staff member (ESTAFF), where "staff" was a generic term for each staff member included in the study: the first operator (FO), the second operator (ESO), a virtual maximum operator (MO), and all additional supporting staff, including the sterile nurse, nonsterile nurse, anaesthesiologist, and radiation technician. The primary outcome was the median cumulative ESTAFF (or EFO, EMO, and so on), which was presented as the median cumulative dose per intervention and stratified for several within-interventional EVAR and F/BrEVAR steps or stents. The second outcome was the percentage of the absorbed E by a supporting staff member in relation to the E measured by the reference badge attached on the C-arm (ESTAFF% or EFO%, EMO%, and so on). All outcomes are presented as median with interquartile range, unless stated differently. RESULTS: The occupational effective dose in millisieverts of the MO (EMO) was 0.055 (0.029-0.082) for aortouni-iliac stenting (n = 6), 0.084 (0.054-0.141) during thoracic EVAR (n = 14), 0.036 (0.026-0.068) during bifurcated EVAR (n = 38), 0.054 (0.035-0.126) during iliac branched device deployment (n = 8), and 0.345 (0.235-0.757) during F/BrEVAR (n = 24). The median EMO in millisieverts was 0.025 (0.012-0.062) per renal target vessel (TV) and 0.146 (0.07-0.315) for a nonrenal visceral TV. During all noncomplex interventions, the EMO% was 4.4% (2.7%-7.3%), with the lowest median rate at 3.5% (2.5%-5%) for EVAR. The highest median rate EMO% was found for F/BrEVAR procedures: 8.2% (5.0%-14.4%). CONCLUSIONS: With maximum operator shielding during femoral access, relative occupational radiation risk can be minimized. However, digital subtraction angiography image acquisition, recanalization of TVs, recanalization of superior mesenteric artery or celiac artery, and recanalization of branched TVs are predictors for increased occupational radiation dose risks caused by increased radiation doses to the patient and reduced options for shielding of the operator.