Machine Learning Based Prediction of Post-operative Infrarenal Endograft Apposition for Abdominal Aortic Aneurysms.

OBJECTIVE: Challenging infrarenal aortic neck characteristics have been associated with increased risk of a type Ia endoleak after endovascular aneurysm repair (EVAR). Short apposition (< 10 mm circumferential shortest apposition length [SAL]) on the first post-operative computerised tomography angiography (CTA) has been associated with type Ia endoleak. Therefore, this study aimed to develop a model to predict post-operative SAL in patients with an abdominal aortic aneurysm based on the pre-operative shape. METHODS: A statistical shape model was developed to obtain principal component scores. The dataset comprised patients treated with standard EVAR without complications (n = 93) enriched with patients with a late type Ia endoleak (n = 54). The infrarenal SAL was obtained from the first post-operative CTA and subsequently binarised (< 10 mm and ≥ 10 mm). The principal component scores that were statistically different between the SAL groups were used as input for five classification models, and evaluated by means of leave one out cross validation. Area under the receiver operating characteristics curves (AUC), accuracy, sensitivity, and specificity were determined for each classification model. RESULTS: Of the 147 patients, 24 patients had an infrarenal SAL < 10 mm and 123 patients had a SAL ≥ 10 mm. The gradient boosting model resulted in the highest AUC of 0.77. Using this model, 114 (78.0%) patients were correctly classified; sensitivity (< 10 mm apposition was correctly predicted) and specificity (≥ 10 mm apposition was correctly predicted) were 0.70 and 0.79, and were based on a threshold of 0.21, respectively. CONCLUSION: A model was developed to predict which patients undergoing EVAR will achieve sufficient graft apposition (≥ 10 mm) in the infrarenal aortic neck based on a statistical shape model of pre-operative CTA data. This model can help vascular specialists during the planning phase to accurately identify patients who are unlikely to achieve sufficient apposition after standard EVAR.

Geometric Analysis of the Gore Excluder Conformable Endoprosthesis in the Infrarenal Aortic Neck: One Year Results of the EXCeL Registry.

OBJECTIVE: The Gore Excluder Conformable Endoprosthesis (CEXC) is designed to treat challenging infrarenal anatomy because of its active angulation control, repositionability, and enhanced conformability. This study evaluated 30 day and one year position and apposition of the CEXC in the infrarenal neck. METHODS: Patients treated with the CEXC between 2018 and 2022 with an available 30 day computed tomography angiogram (CTA) were selected from four hospitals in a prospective registry. Endograft apposition (shortest apposition length [SAL]) and position (shortest fabric distance [SFD]) were assessed on the 30 day and one year CTAs. Maximum infrarenal aortic curvature was compared between the pre- and post-operative CTAs to evaluate conformability of the CEXC. RESULTS: There were 87 patients with a 30 day CTA, and for 56 of these patients the one year CTA was available. Median (interquartile range [IQR]) pre-operative neck length was 22 mm (IQR 15, 32) and infrarenal angulation was 52° (IQR 31, 72). Median SAL was 21.2 mm (IQR 14.0, 29.3) at 30 days for all included patients. The SAL in 13 patients (15%) was < 10 mm at 30 days, and one patient had a SAL of 0 mm and a type Ia endoleak. There was no significant difference in SAL between patients within and outside instructions for use. The SAL significantly increased by 1.1 mm (IQR -2.3, 4.7; p = .042) at one year. The SAL decreased in seven patients (13%), increased in 13 patients (23%), and remained stable in 36 patients (64%). Median SFD was 2.0 mm (IQR 0.5, 3.6) at 30 days, which slightly increased by 0.3 mm (IQR -0.5, 1.8; p = .019) at one year. One patient showed migration (SFD increase ≥ 5 mm). Median endograft tilt was 15.8° (IQR 9.7, 21.4). Pre-operative maximum infrarenal curvature was 36 m-1 (IQR 26, 56) and did not significantly change thereafter. CONCLUSION: In most patients, the CEXC was implanted close to the renal arteries, and sufficient (≥ 10 mm) post-operative apposition was achieved at 30 days, which slightly increased at one year. Post-operative endograft tilt was relatively low, and aortic geometry remained unchanged after implantation of the CEXC, probably due to its high conformability.

Safety and Feasibility of the BYCROSS® Atherectomy Device for the Treatment of Femoropopliteal Arterial Obstructions: Single-Center Short-Term Outcomes.

Background: Endovascular techniques have gained preference over peripheral arterial bypass surgery due to their minimally invasive nature; however, endovascular treatments often show limited efficacy in arterial segments with a high atherosclerotic load. The use of atherectomy devices enables the removal of calcified plaque material and may promote arterial wall remodeling. This study assessed the technical success, safety, and feasibility of the BYCROSS® atherectomy device in femoropopliteal lesions. Methods: This single-center, retrospective cohort study analyzed elective patients undergoing BYCROSS® atherectomy for chronic peripheral arterial disease from March 2022 to May 2023. Patient data, procedural details, and outcomes were retrospectively collected from electronic patient records. The primary performance endpoints of this study were technical success, complications, and patency rates. Primary safety endpoints included 30-day and short-term major adverse limb events (MALEs), major adverse cardiovascular events (MACEs), and mortality rate. Results: The study included 19 patients (median age, 71 years; 63% male) with Fontaine class IIb (26%), III (21%), or IV (53%). The BYCROSS® atherectomy device was used to treat 22 limbs in the femoropopliteal tract, of which 11 lesions (50%) were occlusions and 11 were stenoses, with a median length of 24 cm (interquartile range: 17-38). Technical success was achieved in all cases: 4.5% required atherectomy only, 50% required additional balloon angioplasties, 41% required balloon angioplasties and stenting, and 4.5% required segments only stenting. Additional treatment of below-the-knee arteries was performed in 12 patients. Procedurally related complications (not limited to the use of the BYCROSS® device) occurred in 23% of limbs, including distal embolization and laceration. At 30 days, mortality was 5%, the MACE rate was 11%, and the MALE rate was 0%. The observed mortality rate was not directly related to the procedure. Patency (<50% restenosis at duplex ultrasound) was 83% at 30 days. Conclusions: The use of the BYCROSS® atherectomy device for the treatment of femoropopliteal lesions appears to be safe and feasible, with high technical success and low MALE and MACE rates in a challenging population with long-segment femoropopliteal lesions. Long-term follow-up in larger patient series is needed to confirm these findings and to determine the durability of this technique.

Health Literacy and Disease Knowledge of Patients With Peripheral Arterial Disease or Abdominal Aortic Aneurysm: A Scoping Review.

OBJECTIVE: This scoping review summarises health literacy and disease knowledge in patients with abdominal aortic aneurysm (AAA) or peripheral arterial disease (PAD) and the influencing factors. DATA SOURCES: A systematic search was conducted in PubMed, Embase, PsychINFO, and CINAHL covering the period January 2012 to October 2022. REVIEW METHODS: This scoping review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Inclusion criteria encompassed studies addressing health literacy, knowledge, perception, or awareness in patients with AAA or PAD. Two authors independently reviewed abstracts and full texts, resolving any discrepancies through discussion or by consulting a third author for consensus. All article types were included except letters, editorials, study protocols, reviews, and guidelines. No language restrictions were applied. Primary outcomes were health literacy and disease knowledge. Secondary outcomes were factors that could influence this. Quality assessment was done using the Mixed Methods Appraisal Tool (MMAT). RESULTS: The review included 32 articles involving a total of 5 268 patients. Four articles reported health literacy and the rest disease knowledge. Ten studies (31%) met all quality criteria. Twenty studies were quantitative, eight were qualitative, and four were mixed methods studies. The review revealed inadequate health literacy in the majority of patients, and disease knowledge was relatively low among patients with AAA and PAD, with disparities in measures and assessment tools across studies. Factors influencing health literacy and disease knowledge included socioeconomic status, education, income, and employment. CONCLUSION: This scoping review revealed low health literacy and low disease knowledge in patients with AAA and PAD. Standardised health literacy assessment may contribute to improve communication strategies and decision aids to enhance patients' understanding and engagement in healthcare decisions, however further research is needed to prove its merits.

Development of a Statistical Shape Model and Assessment of Anatomical Shape Variations in the Hemipelvis.

Knowledge about anatomical shape variations in the pelvis is mandatory for selection, fitting, positioning, and fixation in pelvic surgery. The current knowledge on pelvic shape variation mostly relies on point-to-point measurements on 2D X-ray images and computed tomography (CT) slices. Three-dimensional region-specific assessments of pelvic morphology are scarce. Our aim was to develop a statistical shape model of the hemipelvis to assess anatomical shape variations in the hemipelvis. CT scans of 200 patients (100 male and 100 female) were used to obtain segmentations. An iterative closest point algorithm was performed to register these 3D segmentations, so a principal component analysis (PCA) could be performed, and a statistical shape model (SSM) of the hemipelvis was developed. The first 15 principal components (PCs) described 90% of the total shape variation, and the reconstruction ability of this SSM resulted in a root mean square error of 1.58 (95% CI: 1.53-1.63) mm. In summary, an SSM of the hemipelvis was developed, which describes the shape variations in a Caucasian population and is able to reconstruct an aberrant hemipelvis. Principal component analyses demonstrated that, in a general population, anatomical shape variations were mostly related to differences in the size of the pelvis (e.g., PC1 describes 68% of the total shape variation, which is attributed to size). Differences between the male and female pelvis were most pronounced in the iliac wing and pubic rami regions. These regions are often subject to injuries. Future clinical applications of our newly developed SSM may be relevant for SSM-based semi-automatic virtual reconstruction of a fractured hemipelvis as part of preoperative planning. Lastly, for companies, using our SSM might be interesting in order to assess which sizes of pelvic implants should be produced to provide proper-fitting implants for most of the population.

Carotid calcium burden derived from computed tomography angiography as a predictor of all-cause mortality after carotid endarterectomy.

OBJECTIVE: Carotid endarterectomy (CEA) aims to reduce the risk of stroke in patients with atherosclerotic carotid disease. Preoperative risk assessments that predict complications are needed to optimize the care in this patient group. The current approach, namely relying solely on symptomatology and degree of stenosis, is outdated and calls for innovation. The Agatston calcium score was applied in several vascular specialties to assess cardiovascular risk profile but has been little studied in carotid surgery. It is hypothesized that a higher calcium burden at initial presentation equates to a worse prognosis attributable to an increased cerebrovascular and cardiovascular risk profile. The aim was to investigate the association between preoperative ipsilateral calcium score and postoperative all-cause mortality in patients undergoing CEA. METHODS: This single-center retrospective cohort study included 89 patients who underwent CEA at a tertiary referral center between 2010 and 2018. Preoperative calcium scores were measured on contrast-enhanced computed tomography images with patient-specific Hounsfield thresholds at the level of the carotid bifurcation. The association between these calcium scores and all-cause mortality was analyzed using multivariable adjusted Cox proportional hazard analysis. RESULTS: Cox proportional hazard analysis demonstrated a significant association between preoperative ipsilateral carotid calcium score and all-cause mortality (hazard ratio, 1.10; 95% confidence interval, 1.03-1.16; P = .003). After adjusting for age, preoperative estimated glomerular filtration rate, and diabetes mellitus, a significant association remained (hazard ratio, 1.07; 95% confidence interval, 1.00-1.15; P = .05). CONCLUSIONS: A higher calcium burden was predictive of worse outcome, which might be explained by an overall poorer health status. These results highlight the potential of calcium measurements in combination with other traditional risk factors, for preoperative risk assessment and thus for improved patient education and care.

Determining the Reliable Measurement Period for Preoperative Baseline Values With Telemonitoring Before Major Abdominal Surgery: Pilot Cohort Study.

BACKGROUND: Preoperative telemonitoring of vital signs, physical activity, and well-being might be able to optimize prehabilitation of the patient's physical and mental condition prior to surgery, support setting alarms during in-hospital monitoring, and allow personalization of the postoperative recovery process. OBJECTIVE: The primary aim of this study was to evaluate when and how long patients awaiting major abdominal surgery should be monitored to get reliable preoperative individual baseline values of heart rate (HR), daily step count, and patient-reported outcome measures (PROMs). The secondary aim was to describe the perioperative course of these measurements at home. METHODS: In this observational single-center cohort study, patients used a wearable sensor during waking hours and reported PROMs (pain, anxiety, fatigue, nausea) on a tablet twice a day. Intraclass correlation coefficients (ICCs) were used to evaluate the reliability of mean values on 2 specific preoperative days (the first day of telemonitoring and the day before hospital admission) and randomly selected preoperative periods compared to individual reference values. Mean values of HR, step count, and PROMs per day were visualized in a boxplot from 14 days before hospital admission until 30 days after surgery. RESULTS: A total of 16 patients were included in the data analyses. The ICCs of mean values on the first day of telemonitoring were 0.91 for HR, 0.71 for steps, and at least 0.86 for PROMs. The day before hospital admission showed reliability coefficients of 0.76 for HR, 0.71 for steps, and 0.92-0.99 for PROMs. ICC values of randomly selected measurement periods increased over the continuous period of time from 0.68 to 0.99 for HR and daily step counts. A lower bound of the 95% CI of at least 0.75 was determined after 3 days of measurements. The ICCs of randomly selected PROM measurements were 0.89-0.94. Visualization of mean values per day mainly showed variable preoperative daily step counts (median 2409, IQR 1735-4661 steps/day) and lower postoperative daily step counts (median 884, IQR 474-1605 steps/day). In addition, pain was visually reduced until 30 days after surgery at home. CONCLUSIONS: In this prospective pilot study, for patients awaiting major abdominal surgery, baseline values for HR and daily step count could be measured reliably by a wearable sensor worn for at least 3 consecutive days and PROMs during any preoperative day. No clear conclusions were drawn from the description of the perioperative course by showing mean values of HR, daily step count, and PROM values over time in the home situation.

Feasibility and patient's experiences of perioperative telemonitoring in major abdominal surgery: an observational pilot study.

BACKGROUND: Telemonitoring during the perioperative trajectory may improve patient outcomes and self-management. The aim of this study is to assess the feasibility of and patient's experiences with telemonitoring before and after major abdominal surgery to inform future study design. METHODS: Patients planned for elective major abdominal surgery wore a sensor and answered well-being questions on a tablet daily for at least 2 weeks preoperatively up to 30-days postoperatively. Feasibility was assessed by participation and completion rate, compliance per day, weekly satisfaction scores, and reasons for nonscheduled contact. RESULTS: Twenty-three patients were included (participation rate of 54.5%) with a completion rate of 69.6%. Median compliance with the wearable sensor and well-being questions was respectively: 94.7% and 83.3% preoperatively at home; 100% and 66.7% postoperatively in-hospital; and 95.4% and 85.8% postoperatively at home. Median weekly satisfaction scores for both wearing the sensor and well-being questions were 5 (IQR, 4-5). Contact moments were related to absence of sensor data and technological issues (76.0%) or patient discomfort and insecurity (24.0%). CONCLUSIONS: In this study, telemonitoring showed high satisfaction and compliance during the perioperative trajectory. Future trial design regarding the effectiveness of telemonitoring requires embedding in clinical practice and support for patients, relatives, and healthcare personnel.

Pre-operative Aortic Neck Characteristics and Post-operative Sealing Zone as Predictors of Type 1a Endoleak and Migration After Endovascular Aneurysm Repair: A Systematic Review and Meta-Analysis.

OBJECTIVE: Establishing the predictive value of neck characteristics and real achieved sealing zone is essential to foster risk stratified procedure selection and imaging surveillance. This systematic review provides an overview of pre-operative aortic neck characteristics and post-operative real achieved sealing zone and their respective risk of type 1a endoleak and migration after endovascular aneurysm repair (EVAR). METHODS: In agreement with PRISMA guidelines, MEDLINE, Embase, and Cochrane CENTRAL were searched. Data on neck characteristics, sealing zone, and EVAR outcome were extracted. Meta-analyses were performed to investigate the effect of neck diameter, angulation, and shape on type 1a endoleak (total, early ≤ 90 days, and late > 90 days) and migration in patients who underwent EVAR. A qualitative summary was also provided. RESULTS: Thirty-three studies were included. Patients with a larger neck diameter had an increased risk of total type 1a endoleak (nine studies: OR 3.32, 95% CI 2.38 - 4.63), early type 1a endoleak (six studies: OR 2.64, 95% CI 1.27 - 5.48), late type 1a endoleak (six studies: OR 3.26, 95% CI 2.12 - 5.03), and migration (seven studies: OR 2.88, 95% CI 1.32 - 6.26). An angulated neck increased the risk of total type 1a endoleak (seven studies: OR 4.27, 95% CI 1.55 - 11.78) and late type 1a endoleak (seven studies: OR 5.56, 95% CI 2.19 - 14.13). Neck shape was not associated with type 1a endoleak. Neck length and real achieved sealing zone on post-EVAR computed tomography were identified as risk factors for type 1a endoleak and migration through qualitative summary. CONCLUSION: There seems to be some consistent evidence that aortic neck diameter, angulation, and length are associated with the development of type 1a endoleak or migration. Real achieved sealing zone might be an important addition during follow up. However, a small number of studies, with serious limitations, could be included, and there was considerable variability in reporting patients and outcomes. A proposal for standardisation of aortic and EVAR data in future studies is provided.

Endograft apposition and infrarenal neck enlargement after endovascular aortic aneurysm repair.

BACKGROUND: Sufficient apposition and oversizing of the endograft in the aortic neck are both essential for durable endovascular aneurysm repair (EVAR). These measures are however not regularly stated on post-EVAR computed tomography angiography (CTA) scan reports. In this study endograft apposition and neck enlargement (NE) after EVAR with an Endurant II(s) endograft were analyzed and associated with supra- and infrarenal aortic neck morphology. METHODS: In 97 consecutive elective patients, the aortic neck morphology was measured on the pre-EVAR CTA scan on a 3mensio vascular workstation. The distance between the lowest renal artery and the proximal edge of the fabric (shortest fabric distance, SFD), and the shortest length of circumferential apposition between endograft and aortic wall (shortest apposition length, SAL) were determined on the early post-EVAR CTA scan. NE, defined as the aortic diameter change between pre- and post-EVAR CTA scan, was determined at eight levels: +40, +30, +20, +15, +10, 0, -5 and -10 mm relative to the lowest renal artery baseline. The aortic neck diameter and preoperative oversizing were correlated to NE with the Pearson correlation coefficient. The effective post-EVAR endograft oversizing is calculated from the nominal endograft diameter and the post-EVAR neck diameter where the endograft is circumferentially apposed. RESULTS: The median time (interquartile range, IQR) between the EVAR procedure and the pre- and post-EVAR CTA scan was 40 (25, 71) days and 36 (30, 46) days, respectively. The Endurant II(s) endograft was deployed with a median (IQR) SFD of 1.0 (0.0, 3.0) mm. The SAL was <10 mm in 9% of patients and significantly influenced by the pre-EVAR aortic neck length (P=0.001), hostile neck shape (P=0.017), and maximum curvature at the suprarenal aorta (P=0.039). The median (interquartile range) SAL was 21.0 (15.0, 27.0) mm with a median (IQR) pre-EVAR infrarenal neck length of 23.5 (13.0, 34.8) mm. The median (IQR) difference between the SAL and neck length was -5.0 (-12.0, 2.8) mm. Significant (P<0.001) NE of 1.7 (0.9, 2.5) mm was observed 5 mm below the renal artery baseline, which resulted in an effective post-EVAR endograft oversizing <10% in 43% of the patients. No correlation was found between NE and aortic neck diameter or preoperative oversizing. CONCLUSIONS: Circumferential apposition between an endograft and the infrarenal aortic neck, SAL, and NE can be derived from standard postoperative CT scans. These variables provide essential information about the post-procedural endograft and aortic neck morphology regardless of the preoperative measurements. Patients with SAL<10 mm or effective oversizing <10% due to NE may benefit from intensified follow-up, but clinical consequences of SAL and NE should be evaluated in future longitudinal studies with longer term follow-up.

Hyperspectral imaging for noninvasive tissue perfusion measurements of the lower leg: review of literature and introduction of a standardized measurement protocol with a portable system.

INTRODUCTION: Hyperspectral imaging (HSI) is a noninvasive technique for transcutaneous measurements of tissue perfusion. This study (1) provides a review of the current literature on HSI for tissue perfusion measurements of the lower leg and (2) introduces a standardized measurement protocol for HSI measurements with a portable system. EVIDENCE ACQUISITION: A literature search was performed for studies on tissue perfusion measurements with HSI in the lower extremity. A standardized protocol was developed to perform HSI measurements in 43 healthy volunteers at the plantar side of the foot and at the lateral side of the calf, with 3 consecutive hyperspectral images at each location. EVIDENCE SYNTHESIS: The literature review identified 9 studies, including 2 of healthy volunteers, 4 of patients with diabetes mellitus, and 3 of patients with peripheral arterial disease. In 5 of 7 patient studies, HSI values were associated with severity of disease or wound healing. In our study, the healthy volunteers' HSI values for oxyhemoglobin, deoxyhemoglobin, and oxygen saturation were (mean±SD) 82.8±24, 55.7±15.7, and 59.2±11.7, respectively, at the plantar surface of the foot, and 40.8±11, 38.0±7.8, and 51.7±10.5, respectively, at the lateral side of the calf. HSI values differed significantly between the calf and plantar locations. Intraoperator reliability between the 3 consecutive images ranged from 81% to 89%. CONCLUSIONS: Limited evidence indicates that HSI is associated with severity of peripheral arterial disease and diabetes mellitus, and with wound healing. Hyperspectral images with a portable system can be taken with high precision when a standardized measurement protocol is used. However, differences exist at several locations at the lower extremity, so each measurement location should be used as its own reference when consecutive measurements are performed during follow-up. More studies with larger patient cohorts should be performed before HSI can be incorporated as standard tool in the diagnostic armamentarium of the vascular specialist.

Quantification of muscle mass in the legs of patients with peripheral arterial occlusive disease: associations between volumetric and cross-sectional single-slice measurements for identification of atrophy and focal sarcopenia.

BACKGROUND: Sarcopenia, commonly determined by measuring skeletal muscle mass index (SMI) at the third lumbar level, has been identified as a predictor of clinical outcome in a variety of diseases. For patients with peripheral arterial occlusive disease (PAOD), we hypothesized that lower extremity SMI (LESMI) might be a more precise predictor of outcome and the extent of chronic ischemia than the systemic muscle mass at the L3 level. We investigated the association between complete muscle volume and muscle area derived with single-slice 2-dimensional measurements in the legs to identify at which level cross-sectional single-slice measurements are most representative of the muscle volume and investigated whether LESMI is associated with systemic sarcopenia and PAOD severity. METHODS: Muscle volumes and areas were semiautomatically segmented from computed tomography (CT) scans of the affected and contralateral legs of 50 PAOD patients with Fontaine stage IIb and 50 PAOD patients with Fontaine stage IV. The muscle mass was determined for the complete volumes of the upper and lower legs and for cross-sectional slices at 40%, 50%, and 60% of the length of the femur and tibia. Patients were determined as sarcopenic based on sex-specific cut-off values at the L3 spinal segment. Two observers segmented 20 randomly selected patients to determine the interobserver reliability with the intraclass correlation coefficient. RESULTS: The correlation between the LESMI of the complete muscle volume and the three cross-sectional slices in all 200 upper and 200 lower legs was moderately strong to strong. Interobserver reliability of cross-sectional slice segmentation was excellent. The LESMI, both measured volumetrically and cross-sectionally, were significantly lower in patients with sarcopenia compared to patients without sarcopenia. The LESMI was lower in patients with Fontaine stage IV compared to patients with Fontaine stage IIb for both volumetric and cross-sectional measurements. CONCLUSIONS: Segmentation of skeletal muscle mass from cross-sectional single-slice CT in the upper and lower leg can accurately and precisely substitute complete volume segmentations. These findings warrant the use of measurements based on cross-sectional single-slice CT for assessing the LESMI. Patients with systemic sarcopenia are also at increased risk for muscle mass loss in the lower extremities. In the current study, LESMI was lower in patients with Fontaine class IV PAOD compared to patients with Fontaine class IIb PAOD. Future studies should assess the predictive value of the LESMI on clinical outcomes in PAOD patients.

Telemedicine in patients with peripheral arterial disease: is it worth the effort?

Introduction: For patients with peripheral arterial disease (PAD), the various components of telemedicine, such as telemonitoring, telecoaching, and teleconsultation, could be valuable in daily management. The objective of this review was to give an overview of the current use of telemedicine interventions in PAD. Areas covered: A literature search was performed for studies that evaluated patients with PAD of the aorto-pedal trajectory, who were monitored by telemedicine and acted upon accordingly. The primary outcome was health-related outcomes. The studies that were found focused mainly on wearable activity monitoring and telecoaching in PAD (n = 4) or wound monitoring after vascular surgery (n = 2). Main results indicate that telemedicine interventions are able to detect (post-operative) complications early, improve functional capacity and claudication onset time, and improve PAD patients' quality of life. Expert opinion: The use of telemedicine in PAD patients is still an under-explored area. Studies investigating the use of telemedicine in PAD are very limited and show varying results. Owing to its high potential in improving physical ability, lifestyle coaching, and timely detection of deterioration, future research should focus on proper implementation of telemedicine in PAD patients, including clinical and feasibility outcomes, effect on workload of nurses, and cost-efficiency.

Assessment of changes in stent graft geometry after chimney endovascular aneurysm sealing.

BACKGROUND: Chimney endovascular aneurysm sealing (ch-EVAS) could potentially minimize gutter-associated endoleaks in patients with juxtarenal abdominal aortic aneurysms resulting from the use of the conformable endobags surrounding the chimney stent grafts (ch-SGs). The aim of the present study was to quantify the (non)apposition of the endobags in the proximal aortic neck, migration of the endograft stent frames, and changes in geometry of the ch-SGs during the follow-up period. METHODS: The prospective data from 20 patients undergoing elective ch-EVAS were retrospectively reviewed. The aortic anatomy was analyzed on preoperative and postoperative computed tomography scans. The (non)apposition of the endobags in the aortic neck, Nellix (Endologix, Irvine, Calif) stent frame migration, and chimney graft geometry and migration were assessed. RESULTS: The median preoperative infrarenal neck length was 4.0 mm (interquartile range [IQR], 0-6.0 mm). The median seal length in the juxtarenal aortic neck at the first follow-up was 23.0 mm (IQR 18.0-30.8 mm). Five type IA endoleaks were identified on postoperative imaging; one at 1 month and four newly diagnosed at 1 year. Of these five type IA endoleaks, two were type Is1 (not extending into the aneurysm sac) and did not need reintervention and other three were type Is2 (extending into the aneurysm sac). One of these patients died of malignancy before reintervention could be performed. Bilateral ch-SG occlusions in one patient were documented at the 1-month follow-up (patient needed hemodialysis) and two patients with a new single ch-SG occlusion were found at the 1-year follow-up. No reinterventions were performed for the ch-SG occlusions. An occluded Nellix stent frame in one patient was treated with femorofemoral crossover bypass. Kaplan-Meier estimate of reintervention-free survival was 85.0% after 1 year. Migration ≥5 mm of the proximal end of the Nellix stent frames was observed in 20.0% of the patients, but no reintervention was performed at the 1-year follow-up. Imaging showed 20.1% of the available sealing surface was not used, and the nonapposition surface increased to 30.6% of the preoperative aortic neck surface at 1 year. Median migration was 3.5 mm (IQR, 2.4-5.0 mm) and 3.1 mm (IQR, 2.0-4.8 mm) for the left and right proximal end of the Nellix stent frames, respectively, and was 3.0 mm (IQR, 2.2-4.8 mm) for the proximal end of the ch-SGs at 1 year of follow-up. CONCLUSIONS: Substantial distal migration of the Nellix endograft and positional changes of the ch-SGs in the juxtarenal aortic neck were observed at 1 year of follow-up, resulting in a 25.0% type IA endoleak rate, with three of these type IA endoleaks extending into the aneurysm sac. The reintervention-free survival rate was 85.0% at 1 year in this cohort of 20 patients. Careful follow-up after ch-EVAS is advised because changes are often subtle. The authors have stopped the ch-EVAS procedure so far. Long-term follow-up data on the stability of the Nellix endograft and the consequences of migration on ch-SGs is required before this technique should be used in clinical practice.

Classification of gutter type in parallel stenting during endovascular aortic aneurysm repair.

OBJECTIVE: Gutters can be described as the loss of continuous apposition between the main body of the endograft, the chimney stent graft, and the aortic wall. Gutters have been associated with increased risk of type IA endoleaks and are considered to be the Achilles' heel of chimney endovascular aneurysm repair (ch-EVAR). However, there is no classification yet to classify and quantify gutter types after ch-EVAR. METHODS: Different gutter types can be distinguished by their morphologic appearance in two- and three-dimensional views and reconstructed slices perpendicular to the center lumen line. RESULTS: Three main categories are defined by (1) the most proximal beginning of the gutter, (2) the length of gutter alongside the endograft, and (3) its distal end. Type A gutters originate at the proximal fabric of an endograft, type B gutters originate as loss of apposition of the chimney stent graft in the branch vessel, and type C gutters start below the fabric of the endograft. To determine eventual changes of gutter size during follow-up computed tomography angiograms (CTAs), measurements may be performed with dedicated software on the follow-up CTA scan to assess the extent of gutters over the aortic circumference, ranging from 0° to 360° of freedom, together with the maximum gap between the endograft material and the aortic wall as it appears on reconstructed axial CTA scan slices. CONCLUSIONS: The proposed gutter classification enables a uniform nomenclature in the current ch-EVAR literature and a more accurate risk assessment of gutter-associated endoleaks. Moreover, it allows monitoring of eventual progression of gutter size during follow-up.

A new method for precise determination of endograft position and apposition in the aortic neck after endovascular aortic aneurysm repair.

BACKGROUND: Follow-up imaging after endovascular aortic aneurysm repair (EVAR) focuses on detection of gross abnormalities: endoleaks and significant (>10 mm) migration. Precise determination of endograft position and wall apposition may predict late complications. We present a new measurement method to determine precise position and apposition of endografts in the aortic neck. METHODS: Four patients were selected from our EVAR database. These patients had late (>1 year) type IA endoleak or >1 cm endograft migration. Twenty patients with uneventful follow-up were measured as controls. The new software adds six parameters to define endograft position and neck apposition: fabric distance to renal arteries, tilt, endograft expansion (% of the maximum original diameter), neck surface, apposition surface, and shortest apposition length. These parameters were determined on preoperative and all available postoperative CT-scans, to detect subtle changes during follow-up. RESULTS: All patients with endoleak or migration had increases in fabric distance, tilt, or endograft expansion or decrease of apposition surface. Changes occurred at least one CT scan before the endoleak or migration was noted in the CT reports. The patient without complications showed no changes in position or apposition during follow-up. CONCLUSIONS: The new measurement method detected subtle changes in endograft position and apposition during CT follow-up, not recognized initially. It can potentially determine endograft movements and decrease of apposition surface before they lead to complications like type IA endoleaks or uncorrectable migration. A larger follow-up study comparing complicated and non-complicated EVAR patients is needed to corroborate these results.

Aortic curvature as a predictor of intraoperative type Ia endoleak.

OBJECTIVE: Hostile infrarenal neck characteristics are associated with complications such as type Ia endoleak after endovascular aneurysm repair. Aortic neck angulation has been identified as one such characteristic, but its association with complications has not been uniform between studies. Neck angulation assumes triangular oversimplification of the aortic trajectory, which may explain conflicting findings. By contrast, aortic curvature is a measurement that includes the bending rate and tortuosity and may provide better predictive value for neck complications. METHODS: Data were retrieved from the Heli-FX (Aptus Endosystems, Inc, Sunnyvale, Calif) Aortic Securement System Global Registry (ANCHOR). One cohort included patients who presented with intraoperative endoleak type Ia at the completion angiogram as the indication for EndoAnchors (Aptus Endosystems), and a second cohort comprised those without intraoperative or late type Ia endoleak (controls). The aortic trajectory was divided into six segments with potentially different influence on the stent graft performance: suprarenal, juxtarenal, and infrarenal aortic neck (-30 to -10 mm, -10 to 10 mm, and 10-30 mm from the lowest renal artery, respectively), the entire aortic neck, aneurysm sac, and terminal aorta (20 mm above the bifurcation to the bifurcation). Maximum and average curvature were automatically calculated over the six segments by proprietary custom software. Aortic curvature was compared with other standard neck characteristics, including neck length, neck diameter, maximum aneurysm sac diameter, neck thrombus and calcium thickness and circumference, suprarenal angulation, infrarenal angulation, and the neck tortuosity index. Independent risk factors for intraoperative type Ia endoleak were identified using backwards stepwise logistic regression. For the variables in the final regression model, suitable cutoff values in relation to the prediction of acute type Ia endoleak were defined with the area under the receiver operating characteristic curve. RESULTS: The analysis included 64 patients with intraoperative type Ia endoleak and 79 controls. Logistic regression identified only aortic neck calcification and aortic curvature, expressed over the juxtarenal aortic neck, the aneurysm sac, and the terminal aorta, as independent predictors of intraoperative type Ia endoleak. CONCLUSIONS: Together with aortic neck calcification, aortic curvature appears to be the best predictor of intraoperative type Ia endoleak, as expressed within the juxtarenal aortic neck, the aneurysm sac, and the terminal aorta. Aortic neck angulation was not a predictor for acute failure. Aortic curvature may provide a better anatomic characteristic to define patients at risk for early complications after endovascular aneurysm repair.