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Purpose: To describe the concept of aortic elastic deformation (ED) measurement using duplex ultrasonography (DUS) as a tool for detection of high aneurysm sac pressure following endovascular aortic repair (EVAR)., Technique: High aneurysm sac pressure, with or without proven endoleak, will result in a less compressible aneurysm. Using the dual image function in B-mode of the DUS device and a standardized amount of applied probe pressure, ED can be measured. It is defined as the percentage of deformation of the aneurysm sac on probe pressure application. We hypothesize that less ED of the aneurysm sac can be related with high aneurysm sac pressure and possibly the presence of clinically relevant endoleak. In this note, we describe the technical details of the procedure and report on the applicability and results of ED measurements in the framework of aortic aneurysm and EVAR follow-up in a cohort of 109 patients., Conclusion: ED measurement is the first noninvasive pressure-based method in the quest to find a practical and reliable diagnostic tool to exclude high aneurysm sac pressure. In our patient cohort, patients with proven endoleak showed a smaller ED (less compressible), implying the presence of high aneurysm sac pressure. Further research should confirm whether ED measurement using DUS could reliably exclude endoleak after EVAR and further explore its potential for clinical application in EVAR follow-up., Clinical Impact: For the first time, a simple, fast, and inexpensive diagnostic tool is presented in this study for detecting high sac pressure following EVAR. High sac pressure is typically caused by clinically significant endoleaks, which can have significant consequences. Currently, computed tomography scanning is the most common method used to identify and characterize endoleaks. However, measuring elastic deformation may potentially replace more invasive and expensive modalities, such as the computed tomography in the future., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Foot ulceration is a significant and growing health problem worldwide, particularly due to rises in diabetes mellitus (DM) and peripheral artery disease. The prediction of ulcer healing remains a major challenge. In patients with foot ulcers, medial arterial calcification (MAC) can be present as a result of concomitant DM or chronic kidney disease and is a prognostic factor for unfavorable outcome. This systematic review aimed to evaluate the prognostic reliability of bedside tests to predict ulcer healing and wound healing after minor amputation in patients prone to MAC, following PRISMA guidelines. Primary endpoints were the positive and negative likelihood ratios for ulcer healing. Methodological quality and risk of bias were assessed using the QUIPS-tool. A total of 35 studies were included, predominantly investigating transcutaneous oxygen pressure (TcPO 2 ), followed by ankle-brachial index and toe pressure. None of these bedside tests effectively provided an acceptable trade-off between predicting healing and nonhealing. A TcPO 2 below 30 mmHg was most closely associated with nonhealing of an ulcer. The same applied to wound healing after minor amputation, in which none of the bedside tests was able to sufficiently predict healing or nonhealing. To conclude, currently used bedside tests lack acceptable prognostic performance for ulcer healing and healing after minor amputation in patients prone to MAC. Future prospective studies should establish a clear definition of ulcer healing, utilize a standardized wound classification system, and minimize patient heterogeneity. A combined assessment of microvascular and macrovascular perfusion status could improve the prediction of wound healing., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Identifying peripheral arterial disease (PAD) remains challenging with currently used bedside tests. The maximal systolic acceleration (ACC max ) is a promising noninvasive parameter measured by duplex ultrasonography and reflects the arterial perfusion proximal to its measurement point. The principal aim of this study was to analyze the diagnostic accuracy of the ACC max for detecting significant stenosis in different arterial segments, which could be useful in clinical decision-making., Materials and Methods: A retrospective cohort study was conducted in a tertiary referral hospital. Patients aged 18 years and older who underwent ACC max measurement(s) alongside computed tomography angiography (CTA) of the abdominal aorta and lower extremities were qualified for inclusion. A significant stenosis was defined as a lumen reduction of more than 50% on CTA. Diagnostic accuracy of the ACC max was investigated for the aortoiliac and popliteal arterial pathways., Results: A total of 196 patients (373 limbs) were included in the study. Diagnostic performance of the ACC max (cut-off value of 7.70 m/s 2 ) to detect a significant stenosis in the aortoiliac pathway showed a sensitivity of 89%, specificity of 97%, positive likelihood ratio of 29.23 and negative likelihood ratio of 0.12 (area under the curve [AUC] 0.941). For the popliteal pathway (cut-off value of 6.30 m/s 2 ), these results were 90%, 95%, 17.14 and 0.12, respectively, with an AUC of 0.958., Conclusion: The ACC max showed a promising diagnostic accuracy for detecting a significant stenosis in the aortoiliac and popliteal pathway., Clinical Impact: The maximal systolic acceleration (ACC max ) is a promising non-invasive parameter measured by duplex ultrasonography to diagnose peripheral arterial disease (PAD) and reflects the arterial perfusion proximal to its measurement point. This study focused on its diagnostic accuracy to detect a significant stenosis in the aortoiliac and popliteal pathway, which revealed to be promising with excellent sensitivity and specificity. These findings suggest that ACC max measurements could play a key role in developing a new diagnostic approach for PAD., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: Post-EVAR (endovascular aneurysm repair) aneurysm sac growth can be seen as therapy failure as it is a risk factor for post-EVAR aneurysm rupture. This study sought to identify preoperative patient predictors for developing post-EVAR aneurysm sac growth., Material and Methods: A systematic review was conducted to select potential predictive preoperative factors for post-EVAR sac growth (including a total of 34.886 patients), which were evaluated by a retrospective single-center analysis of patients undergoing EVAR between 2009 and 2019 (N=247) with pre-EVAR computed tomography scans and at least 1 year follow-up. The primary study outcome was post-EVAR abdominal aortic aneurysm (AAA) sac enlargement (≥5 mm diameter increase). Multivariate Cox regression and Kaplan-Meier survival curves were constructed., Results: Potential correlative factors for post-EVAR sac growth included in the cohort analysis were age, sex, anticoagulants, antiplatelets, renal insufficiency, anemia, low thrombocyte count, pulmonary comorbidities, aneurysm diameter, neck diameter, neck angle, neck length, configuration of intraluminal thrombus, common iliac artery diameter, the number of patent lumbar arteries, and a patent inferior mesenteric artery. Multivariate analysis showed that infrarenal neck angulation (hazard ratio, 1.014; confidence interval (CI), 1.001-1.026; p=0.034) and the number of patent lumbar arteries (hazard ratio, 1.340; CI, 1.131-1.588; p<0.001) were associated with post-EVAR growth. Difference in estimated freedom from post-EVAR sac growth for patients with ≥4 patent lumbar arteries versus <4 patent lumbar arteries became clear after 2 years: 88.5% versus 100%, respectively (p<0.001). Of note, 31% of the patients (n=51) with ≥4 patent lumbar arteries (n=167) developed post-EVAR sac growth. In our cohort, the median maximum AAA diameter was 57 mm (interquartile range [IQR] = 54-62) and the median postoperative follow-up time was 54 months (IQR = 34-79). In all, 23% (n=57) of the patients suffered from post-EVAR growth. The median time for post-EVAR growth was 37 months (IQR = 24-63). In 46 of the 57 post-EVAR growth cases (81%), an endoleak was observed; 2.4% (n=6) of the patients suffered from post-EVAR rupture. The total mortality in the cohort was 24% (n=60); 4% (n=10) was AAA related., Conclusions: This study showed that having 4 or more patent lumbar arteries is an important predictive factor for postoperative sac growth in patients undergoing EVAR., Clinical Impact: This study strongly suggests that having 4 or more patent lumbar arteries should be included in preoperative counseling for EVAR, in conjunction to the instructions for use (IFU)., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: After complex endovascular aortic repair (cEVAR), long-term surveillance is advocated to monitor for potential (stent-related) complications. Although various imaging modalities are used, computed tomography angiography remains the standard in current clinical practice worldwide. However, radiopaque markers can cause metal artifacts and scattering, hampering assessment of patency of side branches. The maximal systolic acceleration (ACCmax) is a relatively new duplex ultrasound (DUS) parameter measured distal to a stenosis, avoiding in-stent assessment and scattering. The aim of this article is to illustrate the potential diagnostic utility of the ACCmax after cEVAR and visceral artery stenting in general., Technique: The ACCmax is measured at the maximal slope of the upstroke during the systolic phase in arterial flow. By manually connecting 2 points, a tangent line is created in which the maximal acceleration is automatically calculated and expressed in m/s 2 . A higher value reflects better arterial perfusion proximal to its measurement point. One measurement of a visceral artery takes about 5 minutes., Conclusion: ACC max measurements can be a useful addition during DUS follow-up after cEVAR or visceral artery stenting, possibly decreasing radiation exposure, nephrotoxicity, and health care costs., Clinical Impact: Long-term surveillance after complex endovascular aortic repair (cEVAR) is necessary to monitor for potential (stent-related) complications. Although CTA is the most common modality for imaging, metal artifacts and scattering can hamper the assessment of stent patency. The maximal systolic acceleration (ACCmax) is a duplex ultrasound based parameter that reflects arterial perfusion proximal to its measurement point. Due to its noninvasive nature, it can be a useful addition during follow-up after cEVAR or visceral artery stenting, possibly decreasing radiation exposure, nephrotoxicity and health care costs as well., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Contemporary quality control methods are often insufficient in predicting clinical outcomes after revascularization in lower extremity arterial disease (LEAD) patients. This study evaluates the potential of near-infrared fluorescence imaging with indocyanine green to predict the clinical outcome following revascularization. Near-infrared fluorescence imaging was performed before and within 5 days following the revascularization procedure. Clinical improvement was defined as substantial improvement of pain free walking distance, reduction of rest- and/or nocturnal pain, or tendency toward wound healing. Time-intensity curves and 8 perfusion parameters were extracted from the dorsum of the treated foot. The quantified postinterventional perfusion improvement was compared within the clinical outcome groups. Successful near-infrared fluorescence imaging was performed in 72 patients (76 limbs, 52.6% claudication, 47.4% chronic limb-threatening ischemia) including 40 endovascular- and 36 surgical/hybrid revascularizations. Clinical improvement was observed in 61 patients. All perfusion parameters showed a significant postinterventional difference in the clinical improvement group ( P -values <.001), while no significant differences were seen in the group without clinical improvement ( P -values .168-.929). Four parameters demonstrated significant differences in percentage improvement comparing the outcome groups ( P -values within .002-.006). Near-infrared fluorescence imaging has promising additional value besides clinical parameters for predicting the clinical outcome of revascularized LEAD patients., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

BackgroundIn diagnosing peripheral arterial disease (PAD), medial arterial calcification (MAC) hampers arterial compression and could lead to unreliable ankle brachial index (ABI), toe brachial index (TBI) and toe pressure (TP). Doppler ultrasonography (DUS) derived maximal systolic acceleration (ACCmax) might be more accurate to diagnose PAD. In an in vitro study, a strong correlation between ACCmax and the severity of stenotic disease was determined. The aim of this study was to investigate the ACCmax in correlation with conventional non-invasive diagnostics in an in vivo setting. Methods: In twelve healthy individuals, an arterial stenosis was mimicked by compression on the common femoral artery by an ultrasounds probe, creating a local stenosis of 50%, 70% and 90%. The ABI, TBI, TP and several DUS parameters (including ACCmax) were assessed at the ankle during these different degrees of stenosis. All DUS parameters were measured separately by two observers to determine the interobserver variability. Results: Overall the ABI, TBI, TP, ACCmax, ACCsys and PSV decreased significantly when the degree of stenosis increased. The ACCmax showed the highest correlation with the degree of stenosis (r -.884), compared to ABI (r -.726), TBI (r -.716) and TP (r -.758). Furthermore, the interobserver variability of ACCmax was excellent, with an intraclass correlation coefficient (ICC) of .97. Conclusion: ACCmax is an accurate non-invasive DUS parameter to diagnose and assess the severity of a mimicked arterial stenosis in healthy individuals. Further prospective assessment of the clinical value of ACCmax and its potential benefits in patients with PAD is needed.

Purpose: Complex endovascular aortic repair (EVAR) procedures provide a treatment option for patients with aortic aneurysms involving visceral branches. Good technical results and short-term outcomes have been reported. Whether complex EVAR provides acceptable functional outcomes is not clear. The current study aims to describe postoperative functional outcomes in complex EVAR patients-an older and relatively frail patient group., Materials and Methods: A single-center retrospective cohort study was performed, using data from a computerized database of consecutive patients who underwent complex EVAR in the Leiden University Medical Center (LUMC, The Netherlands) between July 2013 and September 2020. As of May 2017, patients scheduled for complex EVAR were referred to a geriatric care pathway to determine (Instrumental) Activities of Daily Living ((I)ADL) scores at baseline and, if informed consent was given, after 12 months. For the total patient group, adverse functional performance outcomes were: discharge to a nursing home and 12-month mortality. For the patients included in geriatric follow-up, the additional outcome was the incidence of functional decline (defined by a ≥2 point increase in (I)ADL-score) at 12-month follow-up., Results: Eighty-two patients underwent complex EVAR, of which 68 (82.9%) were male. Mean age was 73.3 years (SD=6.3). Within 30 days postsurgery, 6 patients (7.3%) died. Mortality within 12 months for the total patient group was 14.6% (n=12). After surgery, no patients had to be discharged to a nursing home. Fifteen patients (18.3%) were discharged to a rehabilitation center. Twenty-three patients gave informed consent and were included in geriatric follow-up. Five patients (21.7%) presented functional decline 12 months postsurgery and 4 patients had died (17.4%) by that time. This means that 39.1% of the patients in the care pathway suffered an adverse outcome., Conclusion: To our knowledge, this is the only study that examined functional performance after complex EVAR, using a prospectively maintained database. No patients were newly discharged to a nursing home and functional performance results at 12 months are promising. Future multidisciplinary research should focus on determining which patients are most prone to deterioration of function, so that efforts can be directed toward preventing postoperative functional decline.

Background: Failure of maturation occurs in 30%-60% of arteriovenous fistula (AVF) creation for hemodialysis, with highest rates in distal radiocephalic fistulas. This is partly due to initial small blood vessel size with limited blood flow capacity. Forearm exercise has shown potential as stimulus for increasing blood vessel size in patients with end-stage renal disease (ESRD) and may promote maturation of AVFs in the upper limb when applied postoperatively. However, it is unknown if forearm exercise increases blood vessel size pre-operatively, which may contribute to more distal AVF creation and raise success rates of AVF surgery. This study will investigate these issues., Methods and Results: The PINCH trial (refers to 'pinching') is an investigator-initiated, multicenter, single-blinded, randomized controlled trial with 1:1 randomization to perform supervised forearm exercises compared to no exercise 6 weeks pre-operatively before creation of an AVF. Forty patients receiving an AVF will be included. The main study endpoints are blood vessel diameter (cephalic or basilic vein and radial and ulnar artery), AVF surgical plan (radiocephalic or brachiobasilic/cephalic), and three-month (assisted) maturation rate. The burden of the performed forearm exercises will be evaluated using Kidney Disease Quality of Life (KDQOL-SF Dutch version 1.2) and exercise specific questionnaires. The PINCH trial is planned to start in November 2017. Enrollment is expected to be completed at the end of 2019., Conclusions: The PINCH study is the first trial to evaluate the effect of pre-operative, supervised forearm exercises on vein diameter and fistula maturation in hemodialysis patients., Trial Registration: NTR6382.

Purpose: To investigate if an elastomer [polydimethylsiloxane (PDMS)] can be used to effectively treat endoleaks after endovascular aneurysm repair., Methods: A latex aneurysm (36-mm inner diameter sac, 15-mm inner diameter neck) was attached to an in vitro circulation model. The aneurysm was excluded from the circulation by placing an unstented polyester graft. Endoleak types II-IV were created using different setups. While the circulation setup running, the aneurysm was filled with contrast medium and then the biocompatible PDMS elastomer was injected to exclude the endoleaks and the perigraft area. The sac was considered full when all contrast was pushed out of the sac and the elastomer flowed into the proximal efferent lumbar artery. Treatment was successful when the aneurysm was free of endoleak after control angiography., Results: The endoleaks were created successfully in the latex aneurysm models, with contrast present in the sac before "treatment." After elastomer sac filling, all endoleaks were successfully excluded on angiography; there was no leakage of contrast outside the graft lumen in any of the setups. With the type III endoleak, the disruption in the graft material was sealed by the elastomer, while the entire porous graft was encased in elastomer in the type IV endoleak setup. There was no elastomer within the graft lumen in either case., Conclusions: This concept of filling the aneurysm sac with PDMS may lead to a percutaneous treatment for endoleaks. While the results of this study show that PDMS may be used to treat endoleaks in vitro, further tests are required to determine if this approach is suitable in vivo.

Purpose: To investigate whether, and to which extent, the type of graft has influence on the pressure in the aneurysm sac., Methods: The study consisted of a dynamic and a static experiment. In the dynamic experiment, a latex aneurysm was inserted into an in-vitro circulation model, with variable (80-180 mmHg) systemic systolic pressure and a pulse pressure of 40 mmHg. Seven types of devices were used to exclude the aneurysm: a latex reference graft, 3 stentless grafts made of different fabrics, and 3 different types of commercially produced stented grafts used for endovascular aneurysm repair (EVAR). The systolic and diastolic intra-aneurysm pressures (IAP) were measured, along with the pulse pressure. The mean IAP and pulse pressures were compared for each category of graft (stented/stentless) and for each graft. In the static experiments, the compliance of each graft and the latex aneurysm were determined by measuring the change in volume necessary to obtain a change in pressure. Furthermore, the IAP with each graft was measured in a nonpulsatile situation under systolic pressures varying between 60 and 140 mmHg., Results: The experiments showed that, with increasing systemic pressures, there was a small pressure (<5 mmHg) increase in the aneurysm, but there was no significant difference among grafts in the dynamic or the static experiments (p = 0.12 and p = 0.17, respectively). With the 3 stented EVAR grafts, there was less pressure transmission than with the 3 stentless grafts, but this difference was not significant (p>0.05)., Conclusion: This in-vitro study demonstrated that there is a clinically irrelevant pressure transmission through the graft wall and no significant difference in the pressure transmission between stented and stentless grafts.

Purpose: To evaluate the feasibility and accuracy of Roentgen stereophotogrammetric analysis (RSA) versus computed tomography (CT) for detecting stent-graft migration in an in vitro pulsatile circulation model and to study the feasibility of a nitinol endovascular clip (NEC) as an aortic wall reference marker for RSA., Methods: An aortic model with stent-graft was constructed and connected to an artificial circulation with a physiological flow and pressure profile. Tantalum markers and NECs were used as aortic reference markers for RSA analysis. Stent-graft migrations were measured during pulsatile circulation with RSA and CT. CT images acquired with 64 x 0.5-mm beam collimation were analyzed with Vitrea postprocessing software using a standard clinical protocol and central lumen line reconstruction. RSA in the model with the circulation switched off was used as the reference standard to determine stent-graft migration. The measurement errors of RSA and CT were determined during pulsatile circulation., Results: The mean measurement error +/- standard deviation (maximum) of RSA during pulsatile circulation using the tantalum markers was -0.5+/-0.16 (0.7) mm. Using the NEC, the mean (maximum) measurement error was -0.4+/-0.25 (1.1) mm. The mean (maximum) measurement error of CT was -1.1+/-1.17 (2.8) mm., Conclusion: RSA is an accurate and feasible tool to measure stent-graft migration in a pulsatile environment. Migration measurement with RSA was more accurate than CT in this experimental setup. The nitinol clip tested in this study is potentially feasible as an aortic reference marker in patients after endovascular repair.

Purpose: To evaluate in an in vitro model the feasibility and accuracy of Roentgen stereophotogrammetric analysis (RSA) versus computed tomography (CT) for the ability to detect stent-graft migration., Methods: An aortic model was constructed from a 22-mm-diameter Plexiglas tube with 6-mm polytetrafluoroethylene inlays to mimic the renal arteries. Six tantalum markers were placed in the wall of the aortic tube proximal to the renal arteries. Another 6 markers were added to a Gianturco stent, which was cast in Plexiglas and placed inside the aorta and fixed to a micromanipulator to precisely control displacement of the stent along the longitudinal axis. Sixteen migrations were analyzed with RSA software and compared to the micromanipulator. Thirty-two migrations were measured by 3 observers from CT images acquired with 16x0.5-mm beam collimation and reconstructed with a 0.5-mm slice thickness and a 0.4-mm reconstruction interval. Measurements were made with Vitrea postprocessing software using a standard clinical protocol and central lumen line reconstruction. Results of CT were also compared to the micromanipulator., Results: The mean RSA measurement error compared to the micromanipulator was 0.002+/-0.044 mm, and the maximum error was 0.10 mm. There was no statistically significant interobserver variability for CT (p=0.17). The pooled mean (maximum) measurement error of CT was 0.14+/-0.29 (1.00) mm, which was significantly different from the RSA measurement error (p<0.0001)., Conclusion: Detection of endograft migration by RSA is feasible and was significantly more accurate than CT in this nonpulsatile in vitro model.

Purpose: To determine the effect of pulsatile motion of graft-attached pressure sensors on the accuracy of aneurysm sac pressure measurement., Methods: Pressure inside a pressure box was measured with a sensor attached to a stent-graft (Sensorgraft) facing a sensor in fixed position (Sensorbox). Maximum inter-sensor variation of Sensorgraft and Sensorbox was determined in static experiments. Experiments with pulsatile circulation were performed with a compliant and a noncompliant stent-graft at 120/80 mmHg and 160/95 mmHg. Pressure measurements in the box were repeated after the box pressure was increased from 0 to 120 mmHg. Sensorgraft motion was measured by ultrasound. Measurements with Sensorgraft were compared to those with Sensorbox using Pearson correlation coefficients to determine the concordance between the sensors., Results: The maximum inter-sensor variation was 4 mmHg. Increased box pressure induced progressive pulsatile graft and sensor motion during all experiments. During the experiments with the compliant graft at systemic pressures of 120/80 and 160/95 mmHg, the maximum inter-sensor variation was exceeded at box pressures of 65 and 75 mmHg, respectively. The sensor motion at these box pressures was 214+/-2.70 microm and 210+/-0.93 microm, respectively. Measurements of Sensorgraft were higher than Sensorbox, up to 13 mmHg at a box pressure of 120 mmHg. The Pearson correlation coefficients during these experiments were 0.99 and 1.00 (p < 0.001), respectively. In the experiments with the noncompliant graft, the maximum inter-sensor variation was not exceeded, and sensor motion was only 7 +/- 0.46 microm and 26 +/- 1.48 microm, respectively. The Pearson correlation coefficient during these experiments was 1.00 (p < 0.001)., Conclusion: Pulsatile sensor motion can influence the accuracy of pressure measurement. More compliant grafts are more susceptible to this phenomenon. Despite false high pressure measurements, stent-graft-attached pressure sensors seem appropriate to follow pressure trends in the aneurysm sac.