Management of depth to achieve timely arteriovenous fistula utilization.

OBJECTIVE: Failure to achieve timely arteriovenous fistulae (AVFs) utilization due to excessive depth (>6 mm) remains an ongoing concern for dialysis access. This study evaluates the outcomes of radiocephalic (RCF) and brachiocephalic (BCF) fistula elevation required for access utilization. METHODS: A retrospective review of all patients undergoing first-time autologous access over 10 years was undertaken. RCF and BCF were analyzed, and cases of initial access failure due to depth alone were selected for study. Primary and staged brachio-basilic AVF were excluded. Outcomes of early thrombosis, line placement, maturation (successful progression to hemodialysis [HD∖), reintervention, and functional dialysis (continuous HD for 3 consecutive months) were examined. RESULTS: From January 2012 to December 2022, 1733 patients (67% female; mean age, 61 ± 14 years) underwent autologous AVF placement. Of these, 298 patients (17%) had depth-related AVF access issues (BCF, 71% and RCF, 29%). Nineteen percent of these AVFs underwent a primary balloon-assisted maturation (BAM), and 2% had side branch coil embolization before consideration for elevation. The average time to intervention for depth was 11 ± 4 weeks after primary creation. During elevation, side branch ligation occurred in 38% of cases, and 15% underwent intraoperative BAM, The pre-elevation depth was 8.2 ± 3.1 mm, and the mean post-elevation depth was 4.7 ± 2.9 mm (P = .002). Early thrombosis (<18 days) occurred in 4% of cases. There was no mortality, and the 30-day major adverse cardiac event rate was 2%, with a 30-day morbidity of 5%, which was driven by wound issues. Six percent of the AVFs underwent follow-up BAM within 3 months. Mean maturation of the AVFs was 74% ± 3% vs 72% ± 3% (P = .58) for the elevation vs no-elevation groups at 24 weeks, respectively. However, there was an increase in tunneled central line placement in pre-emptive fistula patients due to the delay in maturation (elevation, 17% vs no-elevation, 8%; P = .008). There was a mean successful access time of 6 ± 3 weeks after elevation (16 ± 4 weeks after access creation). There was a median of 2.4 secondary interventions per year after elevation compared with a median of 2.7 secondary interventions per year without elevation. Mean access functionality was 68% ± 8% vs 75% ± 8% at 3 years for the elevation vs no-elevation groups, respectively (P = .25). CONCLUSIONS: Elevation of deep BCF and RCF occurs late after placement but can be successfully achieved with low morbidity and satisfactory long-term functionality. It results in an increase in tunneled central line placement in pre-emptive fistula patients. Elevation is a valuable adjunct to AVF maturation and enhances an autologous access policy.

PEDAL MEDIAL ARTERIAL CALCIFICATION INFLUENCES THE OUTCOMES OF ISOLATED INFRA-MALLEOLAR INTERVENTIONS FOR CHRONIC LIMB-THREATENING ISCHEMIA.

BACKGROUND: Infra-malleolar disease is present in most diabetic patients presenting with tissue loss. Infra-malleolar (pedal) artery disease and pedal medial arterial calcification (pMAC) are associated with major amputation in patients with chronic limb-threatening ischemia (CLTI). This study aimed to examine the impact of pMAC on the outcomes after isolated infra-malleolar (pedal artery) interventions. METHODS: A database of lower extremity endovascular intervention for tissue loss patients between 2007 and 2022 was retrospectively queried. Patients with CLTI were selected, and those undergoing isolated infra-malleolar intervention on the dorsalis pedis and medial and lateral tarsal arteries and who had foot x-rays were identified. X-rays were assessed blindly for pMAC and scored on a scale of 0-5. Patients with concomitant superficial femoral artery (SFA) and tibial interventions were excluded. Intention to treat analysis by the patient was performed. Amputation-free survival (AFS; survival without major amputation) was evaluated. RESULTS: 223 patients (51% female, 87% Hispanic, average age 66 years; 323 vessels) underwent isolated infra-malleolar intervention for tissue loss. All patients had diabetes, 96% had hypertension, 79% had hyperlipidemia, and 63% had chronic renal insufficiency (55% of these were on hemodialysis). Most of the patients had WIfI stage 3 disease and had various stages of pMAC: severe (score=5) in 48%, moderate (score = 2-4) in 31%, and mild (score = 0-1) in 21% of the patients. Technical success was 94%, with a median of 1 vessel treated per patient. All failures were in severe pMAC. Overall, Major Adverse Cardiovascular Events (MACE) was 0.9% at 90 days after the procedure. Following the intervention, most patients underwent a planned forefoot amputation (single digit, multiple digits, ray amputation, or trans-metatarsal amputation). WIfI ischemic grade was improved by 51%. Wound healing at three months was 69%. Those not healing underwent below-knee amputations (BKA). The overall 5-yr-AFS rate was 35±9%. The severity of pMAC was associated with decreased AFS. CONCLUSIONS: PMAC influences the technical and long-term outcomes of Infra-malleolar intervention in diabetes. Severe pMAC is associated with amputation and should be considered as a variable in the shared decision-making of diabetic patients with CLTI.

Transference of outdoor gait-training to treadmill running biomechanics and strength measures: A randomized controlled trial.

Outdoor gait-training has been successful in improving pain and reducing contact time during outdoor running for runners with exercise-related lower leg pain (ERLLP). However, it is unclear if these adaptations translate to gold standard treadmill running and clinical strength assessments. The study purpose was to assess the influence of a 4-week outdoor gait-training intervention with home exercises (FBHE) on treadmill running biomechanics and lower extremity strength compared to home exercises alone (HE) among runners with ERLLP. Seventeen runners with ERLLP were randomly allocated to FBHE and HE groups (FBHE: 3 M, 6F, 23 ± 4 years, 22.0 ± 4.6 kg/m2; HE: 3 M, 5F, 25 ± 5 years, 24.0 ± 4.0 kg/m2). Both groups completed eight sessions of home exercises over 4 weeks. The FBHE group received gait-training through wearable sensors to reduce contact time. Treadmill running gait and clinical strength assessments were conducted at baseline and 4-weeks. Multivariate repeated measures analyses of variance were used to assess the influence of group and timepoint for all outcomes. The FBHE group demonstrated significantly decreased contact time at 4-weeks compared to baseline and the HE group (Mean Difference [MD] range: -42 ms - -39 ms; p-range: <0.001-0.02). The FBHE group had significantly increased cadence (MD: +21 steps/min; p = 0.003) and decreased loading impulse (MD: -51, p < 0.001) during treadmill running at 4-weeks compared to the HE group. Strength did not significantly differ adjusting for multiple comparisons (p > 0.007). The outdoor FBHE intervention transferred to favorable changes in treadmill running biomechanics. Clinicians treating runners with ERLLP patients should implement data-driven outdoor gait-training to maximize patient benefits across running locations.

Attractor reconstruction with reservoir computers: The effect of the reservoir's conditional Lyapunov exponents on faithful attractor reconstruction.

Reservoir computing is a machine learning framework that has been shown to be able to replicate the chaotic attractor, including the fractal dimension and the entire Lyapunov spectrum, of the dynamical system on which it is trained. We quantitatively relate the generalized synchronization dynamics of a driven reservoir during the training stage to the performance of the trained reservoir computer at the attractor reconstruction task. We show that, in order to obtain successful attractor reconstruction and Lyapunov spectrum estimation, the maximal conditional Lyapunov exponent of the driven reservoir must be significantly more negative than the most negative Lyapunov exponent of the target system. We also find that the maximal conditional Lyapunov exponent of the reservoir depends strongly on the spectral radius of the reservoir adjacency matrix; therefore, for attractor reconstruction and Lyapunov spectrum estimation, small spectral radius reservoir computers perform better in general. Our arguments are supported by numerical examples on well-known chaotic systems.

Extracorporal Membrane Oxygenation in Massive Pulmonary Embolism.

BACKGROUND: Massive pulmonary embolism (MPE) carries significant 30-day mortality risk, and a change in societal guidelines has promoted the increasing use of extracorporeal membrane oxygenation (ECMO) in the immediate management of MPE-associated cardiovascular shock. This narrative review examines the current status of ECMO in MPE. METHODS: A literature review was performed from 1982 to 2022 searching for the terms "Pulmonary embolism" and "ECMO," and the search was refined by examining those publications that covered MPE. RESULTS: In the patient with MPE, veno-arterial ECMO is now recommended as a bridge to interventional therapy. It can reliably decrease right ventricular overload, improve RV function, and allow hemodynamic stability and restoration of tissue oxygenation. The use of ECMO in MPE has been associated with lower mortality in registry reviews, but there has been no significant difference in outcomes between patients treated with and without ECMO in meta-analyses. Applying ECMO is also associated with substantial multisystem morbidity due to systemic inflammatory response, bleeding with coagulopathy, hemorrhagic stroke, renal dysfunction, and acute limb ischemia, which must be factored into the outcomes. CONCLUSIONS: The application of ECMO in MPE should be combined with an aggressive interventional pulmonary interventional program and should strictly adhere to the current selection criteria.

Evaluation of Differences in Patellar Height After Patellar Stabilization Procedures Not Intended to Address Patella Alta: A Multicenter Study.

Background: Recent studies have reported conflicting results as to whether isolated medial patellofemoral ligament reconstruction (MPFLr) leads to decreased patellar height. Purpose: To investigate if patellar stabilization surgery not intended to address patella alta influences patellar height. Study Design: Cohort study; Level of evidence, 3. Methods: A multicenter retrospective chart review was conducted, and patients who underwent MPFLr, medializing tibial tuberosity osteotomy (TTO), and/or trochleoplasty between 2016 and 2020 were included. The Caton-Deschamps index (CDI) was calculated from radiographs obtained preoperatively, 2 weeks postoperatively, and 3 months postoperatively. The preoperative CDI value was compared with the 2-week postoperative and 3-month postoperative values according to stabilization procedure (isolated MPFLr, isolated TTO, MPFLr + TTO, MPFLr + trochleoplasty, and MPFLr + trochleoplasty + TTO) using the paired t test. Analyses of the 1-bundle versus 2-bundle MPFLr technique and the presence of lateral retinacular release or lateral retinacular lengthening were conducted on the isolated MPFLr and combined MPFLr + TTO cohorts. Results: A total of 356 knees were included. Statistically significant pre- to postoperative decreases in CDI were seen in all stabilization procedures analyzed (P≤ .017 for all). Within the isolated MPFLr cohort, this significant decrease was seen at 2 weeks postoperatively with the 2-bundle technique (ΔCDI = -0.09; P < .001) but not with the 1-bundle technique (ΔCDI = -0.01; P = .621). Conclusion: The different surgical techniques analyzed in the current study affected patellar height, even when a distalizing TTO was not performed. The decrease was dependent on surgical technique, with a 2-bundle MPFLr leading to a statistically significant decrease and a 1-bundle MPFLr effecting no change.

Endovascular management of acute and subacute venous thoracic outlet syndrome.

Approximately 3% of all patients presenting with Thoracic Outlet Syndrome have a venous etiology (vTOS), which is considered "effort thrombosis". These patients will present with symptomatic deep venous thrombosis or focal subclavian vein (SCV) stenosis. Endovascular management of vTOS occurs in several phases: diagnostic, preoperative therapeutic intervention before decompression, postoperative interventions after decompression, and delayed interventions in the follow-up after decompression. In the diagnostic phase, dynamic SCV venography can establish functional vTOS. Approximately 4,000 patients have been treated for vTOS and reported in the literature since 1970. Declotting of the SCV was followed by surgical decompression in 53% of patients, while in the remainder, surgical decompression alone (18%), endovascular intervention alone (15%), or conservative therapy with anticoagulation (15%) was performed. The initial intervention was predominantly catheter-directed thrombolysis, with <10% of cases undergoing concomitant balloon angioplasty. 93% of cases were successful. In the postoperative phase, balloon angioplasty was performed to correct residual intrinsic SCV disease after vTOS decompression in under 15% of cases. Stents were rarely deployed. Symptom relief was reported as 94 ± 12% (mean ± SD) and 90 ± 23%, respectively for declotting with decompression and declotting alone. In the delayed phase, balloon angioplasty was performed in under 15% of cases to re-establish patency.

Management of spontaneous dissection and rupture of common iliac artery in vascular Ehlers-Danlos syndrome (VEDS).

A 28-year-old male with history of vascular Ehlers-Danlos syndrome (VEDS) presented with left lower extremity acute limb ischemia. Computed tomography angiography demonstrated spontaneous dissection of the left common iliac artery with occlusion and associated contained rupture . Successful stent placement without associated complications was achieved with the following principles: (1) open arterial exposure for endovascular intervention; (2) no touch technique vessel dissection; (3) circumferential proximal arterial felt cuff reinforcement to reduce systolic pulse wave stretch on sutures, and in case of emergent ligation; and (4) pledgetted "preclose U" stitch monofilament suture prior to access.

Estimating the master stability function from the time series of one oscillator via reservoir computing.

The master stability function (MSF) yields the stability of the globally synchronized state of a network of identical oscillators in terms of the eigenvalues of the adjacency matrix. In order to compute the MSF, one must have an accurate model of an uncoupled oscillator, but often such a model does not exist. We present a reservoir computing technique for estimating the MSF given only the time series of a single, uncoupled oscillator. We demonstrate the generality of our technique by considering a variety of coupling configurations of networks consisting of Lorenz oscillators or Hénon maps.

Synchronizing chaos using reservoir computing.

We attempt to achieve complete synchronization between a drive system unidirectionally coupled with a response system, under the assumption that limited knowledge on the states of the drive is available at the response. Machine-learning techniques have been previously implemented to estimate the states of a dynamical system from limited measurements. We consider situations in which knowledge of the non-measurable states of the drive system is needed in order for the response system to synchronize with the drive. We use a reservoir computer to estimate the non-measurable states of the drive system from its measured states and then employ these measured states to achieve complete synchronization of the response system with the drive.

No Deficits in Functional Outcomes of the Contralateral Limb Are Seen When the Hamstring Is Harvested for Augmentation of Small Diameter Ipsilateral Hamstring Autograft.

Purpose: To evaluate clinical outcomes of the contralateral, nonoperative limb in patients undergoing contralateral hamstring (HS) autograft harvest compared with patients undergoing ipsilateral HS autograft harvest alone. Methods: This study included 96 patients who underwent isolated anterior cruciate ligament reconstruction (ACLR) using 4-stranded HS autograft (n = 85) or 4-stranded HS autograft augmented with contralateral HS (n = 13) due to inclusion of ipsilateral graft diameter <8 mm. Isokinetic flexion and extension strength and dynamic performance of the ipsilateral and contralateral limbs and limb symmetry index (LSI) were evaluated at 6 months' postoperatively. Rates of contralateral native ACL tear at minimum 2 years also were compared. For all comparisons, P < .05 was considered statistically significant. Results: Normalized isokinetic knee flexion and extension strength of the contralateral limb did not differ between cohorts (P = .34; P = .21, respectively). LSI for knee extension peak torque and knee flexion peak torque did not differ between cohorts (P = .44; P = .67, respectively). No difference in LSI was seen for any dynamic performance testing (single leg hop, P = .97; triple leg hop, P = .14; 6-m timed hop, P = .99). No difference was observed in International Knee Documentation Committee (P = .99) or Knee Injury and Osteoarthritis Outcome Score subscale measures (P = .39-.86). No difference in rates of contralateral knee native ACL tears were seen between cohorts (HS autograft + contralateral HS augmentation, n = 2, 15.4%; HS autograft, n = 7, 8.4%; P = .26). Conclusions: In this study, at the time of return to sport, we found no differences in contralateral limb functional performance or limb symmetry measurements between patients undergoing contralateral HS autograft harvest for augmentation of smaller (<8 mm) diameter HS autografts harvested from the injured extremity. Level of Evidence: Level III, retrospective cohort study.

Athlete Muscular Phenotypes Identified and Compared with High-Dimensional Clustering of Lower Limb Muscle Volume Measurements.

INTRODUCTION: Athletes use their skeletal muscles to demonstrate performance. Muscle force generating capacity is correlated with volume, meaning that variations in sizes of different muscles may be indicative of how athletes meet different demands in their sports. Medical imaging enables in vivo quantification of muscle volumes; however, muscle volume distribution has not been compared across athletes of different sports. PURPOSE: The goal of this work was to define "muscular phenotypes" in athletes of different sports and compare these using hierarchical clustering. METHODS: Muscle volumes normalized by body mass of athletes (football, baseball, basketball, or track) were compared with control participants to quantify size differences using z -scores. z -Scores of 35 muscles described the pattern of volume deviation within each athlete's lower limb, characterizing their muscular phenotype. Data-driven high-dimensional clustering analysis was used to group athletes presenting similar phenotypes. Efficacy of clustering to identify similar phenotypes was demonstrated by grouping athletes' contralateral limbs before other athletes' limbs. RESULTS: Analyses revealed that athletes did not tend to cluster with others competing in the same sport. Basketball players with similar phenotypes grouped by clustering also demonstrated similarities in performance. Clustering also identified muscles with similar volume variation patterns across athletes, and principal component analysis revealed specific muscles that accounted for most of the variance (gluteus maximus, sartorius, semitendinosus, vastus medialis, vastus lateralis, and rectus femoris). CONCLUSIONS: Athletes exhibit heterogeneous lower limb muscle volumes that can be characterized and compared as individual muscular phenotypes. Clustering revealed that athletes with the most similar phenotypes do not always play the same sport such that patterns of muscular heterogeneity across a group of athletes reflect factors beyond their specific sports.

Development and Evaluation of an Enhanced Recovery Protocol to Reduce Length of Stay following Elective Endovascular Aneurysm Repair.

BACKGROUND: Elective endovascular abdominal aortic aneurysm repair (EVAR) can be performed safely with a short postoperative length of stay (LOS). We aimed to develop and assess the impact of an enhanced recovery protocol (ERP) on LOS after elective EVAR. METHODS: Pre-ERP development single center retrospective review of elective EVAR procedures from January 2012 to December 2019. ERP was developed by targeting factors associated with prolonged LOS (>2 days) elucidated from semistructured interviews and Bayesian additive regression tree analysis. Post-ERP development, a subsequent retrospective review of elective EVAR performed from January 2018 to June 2021 was performed to evaluate LOS before and after ERP. Primary outcome was LOS. RESULTS: Two hundred sixteen patients underwent elective infrarenal EVAR from 2012 to 2019. Periprocedural factors identified as associated with LOS >2 days included noncommercial insurance (43.6% vs. 26.5%; P = 0.01), preoperative anemia (hemoglobin 12.56 g/dL vs. 13.57 g/dL; P = 0.001), worse renal function (creatinine 1.31 mg/dL vs. 1.01/dL; P = 0.004), open femoral access (74.4% vs. 26.5%; P < 0.001), intensive care unit (ICU) stay (2.7 days vs. 0.9 days; P < 0.001), postoperative anemia (9.8 g/dL vs. 11.9 g/dL; P < 0.001), postoperative creatinine (1.55 mg/dL vs. 0.97 mg/dL; P < 0.001), and beta blocker need on discharge (45.5% vs. 25%; P = 0.003) as significant between patients with short and prolonged LOS groups. Semistructured interviews revealed postoperative day 1 complete blood count/chemistry, postoperative physical therapy evaluation, ICU admission, urinary retention, patient expectations, and unavailability of transportation home as modifiable factors that delayed early discharge. A 14-component ERP was created to target the factors identified from combined qualitative and quantitative results. Post-ERP development, 74 elective EVAR patients were reviewed from 2018 to 2021 (37 pre-ERP and 37 post-ERP). Following ERP development, the mean LOS was reduced from 2.6 (standard deviation: 1.9) to 1.3 days (standard deviation: 1.3); P < 0.01. There were no significant differences in 30-day readmission, postoperative complications, emergency room visits, or 90-day mortality before and after the ERP was used. CONCLUSIONS: Practice and procedural factors can be modified through an informed and safe process to reduce LOS after elective EVAR. LOS following elective EVAR was safely reduced following the use of a systematically developed ERP.

Venous thoracic outlet syndrome and hemodialysis.

Central venous stenotic disease is reported in 7%-40% of patients needing a central venous catheter for dialysis and in 19%-41% of hemodialysis patients who have had a prior central venous catheter. Half of these patients will be asymptomatic. Venous Thoracic Outlet syndrome in hemodialysis (hdTOS) is part of this spectrum of disease. The extrinsic mechanical compression of the subclavian vein at the costoclavicular triangle between the clavicle and 1st rib results in an area of external compression with a predisposition to intrinsic mural disease in the vein. The enhanced flow induced by the presence of a distal arteriovenous access in all patients exacerbates the subclavian vein's response to ongoing extrinsic and intrinsic injury. Repeated endovascular interventions during the maintenance of vascular access accelerates chronic untreatable occlusion of the subclavian vein in the long term. Similar to patients with central venous stenosis, patients with hdTOS can present immediately after access formation with ipsilateral edema or longitudinally with episodes of access dysfunction. hdTOS can be treated in an escalating manner with arteriovenous access flow reduction to <1,500 ml/min, endovascular management, surgical decompression by first rib resection in healthy patients and medial clavicle resection in less healthy patients followed by secondary venous interventions, or finally, a venous bypass. hdTOS represents a complex and evolving therapeutic conundrum for the dialysis community, and additional clinical investigations to establish robust algorithms are required.

Time-shift selection for reservoir computing using a rank-revealing QR algorithm.

Reservoir computing, a recurrent neural network paradigm in which only the output layer is trained, has demonstrated remarkable performance on tasks such as prediction and control of nonlinear systems. Recently, it was demonstrated that adding time-shifts to the signals generated by a reservoir can provide large improvements in performance accuracy. In this work, we present a technique to choose the time-shifts by maximizing the rank of the reservoir matrix using a rank-revealing QR algorithm. This technique, which is not task dependent, does not require a model of the system and, therefore, is directly applicable to analog hardware reservoir computers. We demonstrate our time-shift selection technique on two types of reservoir computer: an optoelectronic reservoir computer and the traditional recurrent network with a t a n h activation function. We find that our technique provides improved accuracy over random time-shift selection in essentially all cases.

Using load sensing insoles to identify knee kinetic asymmetries during landing in patients with an Anterior Cruciate Ligament reconstruction.

BACKGROUND: Knee extension moment asymmetry is a known second anterior cruciate ligament injury risk factor in patients who have had an anterior cruciate ligament reconstruction. Traditionally, assessing asymmetries requires motion capture and force platforms which are expensive and occupy a large space. Wireless force sensing insoles could be a feasible surrogate. METHODS: Twenty-nine patients following anterior cruciate ligament reconstruction performed ten bilateral stop jumps while insole forces, ground reaction forces, and lower extremity kinematics were collected. Peak knee extension moment symmetry was computed using the kinematic and kinetic data, and peak impact force symmetry and impulse symmetry were computed using both the insole force data and vertical ground reaction force data. The relationship between outcomes was analyzed using Pearson correlation coefficients. Patients were classified as symmetric or asymmetric for each outcome based on an 85% symmetry cutoff. The resulting classifications were qualitatively compared across outcome measures. FINDINGS: Peak knee extension moment symmetry had a strong association with the force plate symmetry outcomes (r = 0.72-0.96, p < 0.001) and a moderate to strong association with insole symmetry outcomes (r = 0.67-0.77, p < 0.001). There was strong agreement between insole and force plate symmetry outcomes (r = 0.69-0.90, p < 0.001). Four patients were identified as symmetric when using the peak knee extension moment symmetry, five when using force plate data, and eight when using insole data. INTERPRETATION: Force sensing insoles could be used as a surrogate for knee extension moment asymmetry in patients who have had an anterior cruciate ligament reconstruction.