Two classes of action-stabilizing synergies reflecting spinal and supraspinal circuitry.

We explored force-stabilizing synergies during accurate four-finger constant force production tasks in spaces of finger modes (commands to fingers computed to account for the finger interdependence) and of motor unit (MU) firing frequencies. The main specific hypothesis was that the multifinger synergies would disappear during unintentional force drifts without visual feedback on the force magnitude, whereas MU-based synergies would be robust to such drifts. Healthy participants performed four-finger accurate cyclical force production trials followed by trials of constant force production. Individual MUs were identified in the flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC). Principal component analysis was applied to motor unit frequencies to identify robust MU groups (MU-modes) with parallel scaling of the firing frequencies in FDS, in EDC, and the combined MUs of FDS + EDC. The framework of the uncontrolled manifold hypothesis was used to quantify force-stabilizing synergies when visual feedback on the force magnitude was available and 15 s after turning the visual feedback off. Removing visual feedback led to a force drift toward lower magnitudes, accompanied by the disappearance of multifinger synergies. In contrast, MU-mode synergies were minimally affected by removing visual feedback off and continued to be robust for the FDS and for the EDC, while being absent for the (FDS + EDC) analysis. We interpret the findings within the theory of hierarchical control of action with spatial referent coordinates. The qualitatively different behavior of the multifinger and MU-mode-based synergies likely reflects the difference in the involved neural circuitry, supraspinal for the former and spinal for the latter.NEW & NOTEWORTHY Two types of synergies, in the space of commands to individual fingers and in the space of motor unit groups, show qualitatively different behaviors during accurate multifinger force-production tasks. After removing visual feedback, finger force synergies disappear, whereas motor unit-based synergies persist. These results point at different neural circuitry involved in these two basic classes of synergies: supraspinal for multieffector synergies, and spinal for motor unit-based synergies.

Force matching: motor effects that are not reported by the actor.

We explored unintentional drifts of finger forces during force production and matching task. Based on earlier studies, we predicted that force matching with the other hand would reduce or stop the force drift in instructed fingers while uninstructed (enslaved) fingers remain unaffected. Twelve young, healthy, right-handed participants performed two types of tasks with both hands (task hand and match hand). The task hand produced constant force at 20% of MVC level with the Index and Ring fingers pressing in parallel on strain gauge force sensors. The Middle finger force wasn't instructed, and its enslaved force was recorded. Visual feedback on the total force by the instructed fingers was either present throughout the trial or only during the first 5 s (no-feedback condition). The other hand matched the perceived force level of the task hand starting at either 4, 8, or 15 s from the trial initiation. No feedback was ever provided for the match hand force. After the visual feedback was removed, the task hand showed a consistent drift to lower magnitudes of total force. Contrary to our prediction, over all conditions, force matching caused a brief acceleration of force drift in the task hand, which then reached a plateau. There was no effect of matching on drifts in enslaved finger force. We interpret the force drifts within the theory of control with spatial referent coordinates as consequences of drifts in the command (referent coordinate) to the antagonist muscles. This command is not adequately incorporated into force perception.

Motor unit-based synergies in a non-compartmentalized muscle.

The concept of synergies has been used to address the grouping of motor elements contributing to a task with the covariation of these elements reflecting task stability. This concept has recently been extended to groups of motor units with parallel scaling of the firing frequencies with possible contributions of intermittent recruitment (MU-modes) in compartmentalized flexor and extensor muscles of the forearm stabilizing force magnitude in finger pressing tasks. Here, we directly test for the presence and behavior of MU-modes in the tibialis anterior, a non-compartmentalized muscle. Ten participants performed an isometric cyclical dorsiflexion force production task at 1 Hz between 20 and 40% of maximal voluntary contraction and electromyographic (EMG) data were collected from two high-density wireless sensors placed on the skin over the right tibialis anterior. EMG data were decomposed into individual motor unit frequencies and resolved into sets of MU-modes. Inter-cycle analysis of MU-mode magnitudes within the framework of the uncontrolled manifold (UCM) hypothesis was used to quantify force-stabilizing synergies. Two or three MU-modes were identified in all participants and trials accounting, on average, for 69% of variance and were robust to cross-validation measurements. Strong dorsiflexion force-stabilizing synergies in the space of MU-modes were present in all participants and for both electrode locations as reflected in variance within the UCM (median 954, IQR 511-1924) exceeding variance orthogonal to the UCM (median 5.82, IQR 2.9-17.4) by two orders of magnitude. In contrast, MU-mode-stabilizing synergies in the space of motor unit frequencies were not present. This study offers strong evidence for the existence of synergic control mechanisms at the level of motor units independent of muscle compartmentalization, likely organized within spinal cord circuitry.

Clopidogrel versus ticagrelor for antiplatelet therapy in transcarotid artery revascularization in the Society for Vascular Surgery Vascular Quality Initiative.

OBJECTIVE: Transcarotid artery revascularization (TCAR) with dynamic flow reversal is a hybrid technique for operative management of carotid artery stenosis. Dual antiplatelet therapy is recommended for patients undergoing TCAR; however, nonresponders to these medications may be predisposed to perioperative thromboembolic complications. Prevalent in up to 44% to 66% of patients taking clopidogrel, high on-treatment platelet reactivity may thus be responsible for a portion of adverse cerebrovascular events in TCAR. A previous single-institution study has demonstrated the use of ticagrelor as a viable alternative to clopidogrel for antiplatelet therapy in patients undergoing TCAR; however, large-scale comparisons between clopidogrel and ticagrelor are needed to confirm the safety of ticagrelor outside of highly selected patients and providers. METHODS: Data from patients enrolled in the Society for Vascular Surgery Vascular Quality Initiative undergoing TCAR with a perioperative antiplatelet therapy regimen including either clopidogrel or ticagrelor from January 2015 to March 2021 were analyzed and compared. Multivariable logistic regression and propensity score matching were used to evaluate the primary 30-day outcomes of stroke, major bleeding event, and combined stroke/myocardial infarction (MI)/death rate while adjusting for baseline characteristics of the patients. RESULTS: A total of 11,973 patients underwent TCAR with a dual antiplatelet therapy regimen that included clopidogrel vs 426 patients with ticagrelor. Compared with patients on clopidogrel, patients on ticagrelor were significantly more likely to have coronary artery disease (51% vs 66%; P < .001), particularly unstable angina or MI within 6 months (3% vs 9%; P < .001), and more likely to have insulin-dependent diabetes mellitus (14% vs 19%; P < .001). The unadjusted 30-day rates of stroke, major bleeding, and combined stroke/MI/death were not statistically significant among both groups (1.3% vs 0.5%; P = .14, 2.4% vs 1.4%; P = .18, and 1.9% vs 1.6%; P = .71], respectively). After multivariable adjustment and propensity matching, these remained statistically insignificant. CONCLUSIONS: Despite a substantially higher medical risk in patients undergoing TCAR with ticagrelor, 30-day rates of stroke, major bleeding events, and combined stroke/MI/death were similar between patients on ticagrelor and clopidogrel as part of adjunctive antiplatelet therapy. Randomized prospective trials, and studies with larger sample sizes and longer follow-up will be needed to better examine the outcome differences in TCAR between these two medications.

Outcomes and strategy of tailored antiplatelet therapy with ticagrelor in patients undergoing transcarotid artery revascularization.

OBJECTIVE: Antiplatelet drug resistance is associated with periprocedural ischemic complications in patients undergoing intravascular stent implantation. Nonresponders are subject to increased risk of stent thrombosis and in-stent stenosis, and high on-treatment platelet reactivity (HTPR) is present in up to 44% of patients taking clopidogrel, a widely used component of dual antiplatelet therapy (DAPT). Evidence points to ticagrelor as a viable alternative to overcome HTPR on clopidogrel. Studies have shown fewer thromboembolic events with ticagrelor therapy; however, results on bleeding risk are mixed, and its safety and efficacy in hybrid operative techniques have yet to be established. Transcarotid artery revascularization (TCAR) is a hybrid procedure to treat severe carotid stenosis. The objective of this study was to establish the safety and efficacy of ticagrelor as part of DAPT in patients undergoing TCAR and to develop a protocol to ensure adequate antithrombotic protection throughout the operative course. METHODS: Data were collected retrospectively for patients undergoing TCAR on DAPT of aspirin and ticagrelor for symptomatic (≥50%) or asymptomatic (≥80%) carotid stenosis. Preoperative platelet reactivity was determined using Thromboelastography with Platelet Mapping (Haemonetics Corporation, Braintree, Mass), with adequate platelet reactivity defined as maximal amplitude produced by adenosine diphosphate <50 mm. The primary safety end point was 30-day major bleeding event rate. Primary efficacy end points were 30-day incidence of ipsilateral cerebrovascular ischemic event (stroke or transient ischemic attack), myocardial infarction, and death. Secondary end points were postoperative length of hospital stay, procedure time, and clamp/flow reversal time. RESULTS: Sixty-seven TCAR procedures with patients receiving periprocedural DAPT of ticagrelor and aspirin were performed during the study period. Patients had an average age of 79 years, and 28 (42%) were symptomatic. The mean procedure time was 45.8 ± 9.2 minutes, with a mean clamp/flow reversal time of 4.8 ± 1.5 minutes, and mean postoperative length of hospital stay of 3.1 ± 2.2 days for inpatients and 1.3 ± 0.8 days for outpatients. Technical success was achieved in all cases, with no 30-day major bleeding events and no occurrence of ipsilateral cerebrovascular ischemic event, myocardial infarction, or death. CONCLUSIONS: Initial experience with ticagrelor as part of DAPT in patients undergoing TCAR demonstrated its safety and efficacy in both symptomatic and asymptomatic disease. No bleeding events or thromboembolic complications occurred. Furthermore, a protocol to administer ticagrelor to assay for HTPR on ticagrelor and consequent medication and patient management is proposed. Ticagrelor may represent a safe and effective alternative to overcome clopidogrel nonresponsiveness in DAPT regimens for TCAR.

Perturbation-induced fast drifts in finger enslaving.

We explored changes in finger forces and in an index of unintentional finger force production (enslaving) under a variety of visual feedback conditions and positional finger perturbations. In particular, we tested a hypothesis that enslaving would show a consistent increase with time at characteristic times of about 1-2 s. Young healthy subjects performed accurate force production tasks under visual feedback on the total force of the instructed fingers (index and ring) or enslaved fingers (middle and little). Finger feedback was covertly alternated between master and enslaved fingers in a random fashion. The feedback could be presented over the first 5 s of the trial only or over the whole trial duration (21 s). After 5 s, the fingers were lifted by 1 cm, and after 15 s, the fingers were lowered to the initial position. The force of the instructed fingers drifted toward lower magnitudes in all conditions except the one with continuous feedback on that force. The force of enslaved fingers showed variable behavior across conditions. In all conditions, the index of enslaving showed a consistent increase with the time constant varying between 1 and 3 s. We interpret the results as pointing at the spread of excitation to enslaved fingers (possibly, in the cortical M1 areas). The relatively fast changes in enslaving under positional finger perturbations suggest that quick changes of the input into M1 from pre-M1 areas can accelerate the hypothesized spread of cortical excitation.

What do people match when they try to match force? Analysis at the level of hypothetical control variables.

We used the theory of control with spatial referent coordinates (RC) to explore how young, healthy persons modify finger pressing force and match forces between the two hands. Three specific hypotheses were tested related to patterns of RC and apparent stiffness (defined as the slope of force-coordinate relation) used in the presence of visual feedback on the force and in its absence. The subjects used the right hand to produce accurate force under visual feedback; further the force could be increased or decreased, intentionally or unintentionally (induced by controlled lifting or lowering of the fingertips). The left hand was used to match force without visual feedback before and after the force change; the match hand consistently underestimated the actual force change in the task hand. The "inverse piano" device was used to compute RC and apparent stiffness. We found very high coefficients of determination for the inter-trial hyperbolic regressions between RC and apparent stiffness in the presence of visual feedback; the coefficients of determination dropped significantly without visual feedback. There were consistent preferred sharing patterns in the space of RC and apparent stiffness between the task and match hands across subjects. In contrast, there was much less consistency between the task and match hands in the magnitudes of RC and apparent stiffness observed in individual trials. Compared to the task hand, the match hand showed consistently lower magnitudes of apparent stiffness and, correspondingly, larger absolute magnitudes of RC. Involuntary force changes produced by lifting and lowering the force sensors led to significantly lower force changes compared to what could be expected based on the computed values of apparent stiffness and sensor movement amplitude. The results confirm the importance of visual feedback for stabilization of force in the space of hypothetical control variables. They suggest the existence of personal traits reflected in preferred ranges of RC and apparent stiffness across the two hands. They also show that subjects react to external perturbations, even when instructed "not to interfere": Such perturbations cause unintentional and unperceived drifts in both RC and apparent stiffness.

Outcomes of Transcarotid Artery Revascularization (TCAR) in Octogenarians and Older.

BACKGROUND: Carotid revascularization, both endarterectomy (CEA) and transfemoral carotid artery stenting (TFCAS), are associated with an increased risk of adverse outcomes in patients aged ≥80 years. Transcarotid artery revascularization (TCAR) is a technique that combines surgical principles of neuroprotection with less invasive endovascular techniques to treat severe carotid stenosis. Data from a recent registry study comparing TCAR with that of CEA and TFCAS demonstrated no significant difference in outcomes between TCAR and CEA in patients aged ≥80 years, and a significant reduction in stroke and composite outcomes between TCAR and TFCAS in patients aged ≥80 years. To add to these studies, a more in-depth analysis of demographic, procedural, and outcome factors is warranted for elderly patients aged ≥80 years undergoing TCAR. At our center, with a large volume of elderly patients based on local demographics, we expect there will be no significant effect of age on outcome measures between patients aged <80 years and those aged ≥80 years. METHODS: Data were collected retrospectively for patients undergoing TCAR for symptomatic (≥50%) or asymptomatic (≥80%) extracranial carotid artery stenosis. Primary endpoints were the incidence of ipsilateral cerebrovascular ischemic event (stroke or transient ischemic attack), myocardial infarction (MI), cranial nerve injury, and death through 30 days after the procedure. Secondary endpoints were postoperative length of hospital stay (LOS), procedure time, carotid artery clamp/flow reversal time, and fluoroscopy time. Subgroup analyses were performed to examine the effect of inpatient/outpatient status, carotid symptomatology, and type of anesthesia on secondary outcomes. RESULTS: Ninety-seven TCAR procedures were performed at our institution during the study period, of which 43 (44%) were on patients aged ≥80 years. Technical success was achieved in all cases, with no incidence of cerebrovascular ischemic event, MI, cranial nerve injury, or mortality through 30 days after procedure. In patients aged ≥80 years, the mean procedure time was 47 ± 12 min, clamp/flow reversal time was 4.7 ± 1.1 min, fluoroscopy time was 4.1 ± 1.6 min, and median LOS was 2.0 ± 1.0 days. Procedure time, clamp/flow reversal time, and fluoroscopy time were not significantly different between the age groups. However, there was a significant difference in the LOS, with patients aged <80 years demonstrating a median LOS of 1.0 ± 0.0 days (P = <0.001). CONCLUSIONS: Our experience with TCAR confirms that it can be performed successfully in both symptomatic and asymptomatic high-risk elderly patients, with our series finding no incidence of perioperative cerebral ischemic event, MI, or death.

Intravascular Ultrasound Validation of Contemporary Angiographic Scores Evaluating the Severity of Calcification in Peripheral Arteries.

PURPOSE: To validate 3 angiographic scoring systems for peripheral artery calcification using intravascular ultrasound (IVUS) as the gold standard. METHODS: The study employed preprocedure angiography and IVUS data from 47 patients (median age 72 years; 34 men) in the 55-patient JetStream G3 Calcium Study ( ClinicalTrials.gov identifier NCT01273623) to validate the 3 angiographic scoring systems [Peripheral Academic Research Consortium (PARC), Peripheral Arterial Calcium Scoring System (PACSS), and the DEFINITIVE Ca++ trial]. Preprocedure angiograms were analyzed using conventional quantitative vessel analysis software in 2 orthogonal views. Calcium length was evaluated by markers placed beside the artery during the procedure; calcium deposit(s) were assessed as being on one or both sides of the vessel wall. The 3 calcium scoring systems used these 2 basic angiographic elements to evaluate calcium severity. Based on these criteria, calcium severity varied from none to focal, mild, moderate, or severe in PARC; grade 0 to 4 in PACSS; and none, moderate, or severe in the DEFINITIVE Ca++ system. Calcium location on IVUS was classified as superficial, deep, or mixed. Lesion length was the segment between the most normal looking proximal and distal reference sites. Superficial, deep, and calcium length were based on motorized IVUS pullback. RESULTS: IVUS detected calcium in 44/47 (93.6%) lesions, and angiography detected calcium in 26/47 (55.3%) lesions (p<0.001). The sensitivity, specificity, positive predictive value, and negative predictive value of angiography relative to IVUS were 59%, 100%, 100%, and 14%, respectively. With increasing severity of angiographic calcium, there was a stepwise increase in the prevalence of IVUS superficial calcium and the maximum arc and length of superficial calcium. Using PARC criteria, with increasing severity of calcification, IVUS maximum calcium arc increased from 120° for none to 305° for severe (p<0.001); the length of calcium increased from 7 to 68 mm (p<0.001). Though a similar trend was seen in IVUS superficial calcium, it was not observed in IVUS deep calcium. Similar observations were seen when using the PACSS and DEFINITIVE Ca++ scoring systems. CONCLUSION: IVUS confirmed that the PARC, PACSS, and DEFINITIVE Ca++ calcium scoring systems can be used to classify the degree of calcium in peripheral artery disease, especially superficial calcium.

Outcomes of endovascular aneurysm repair with contemporary volume-dependent sac embolization in patients at risk for type II endoleak.

OBJECTIVE: The aim of this study was to evaluate outcomes of intraoperative aneurysm sac embolization during endovascular aneurysm repair (EVAR) in patients considered at risk for type II endoleak (EII), using a sac volume-dependent dose of fibrin glue and coils. METHODS: Between January 2012 and December 2014, 126 patients underwent EVAR. Based on preoperative computed tomography evaluation of anatomic criteria, 107 patients (85%) were defined as at risk for EII and assigned to randomization for standard EVAR (group A; n = 55, 44%) or EVAR with intraoperative sac embolization (group B; n = 52, 42%); the remaining 19 patients (15%) were defined as at low risk for EII and excluded from the randomization (group C). Computed tomography scans were evaluated with OsiriX Pro 4.0 software to obtain aneurysm sac volume. Freedom from EII, freedom from EII-related reintervention, and aneurysm sac volume shrinkage at 6, 12, and 24 months were compared by Kaplan-Meier estimates. Patients in group C underwent the same follow-up protocol as groups A and B. RESULTS: Patient characteristics, Society for Vascular Surgery comorbidity scores (0.99 ± 0.50 vs 0.95 ± 0.55; P = .70), and operative time (149 ± 50 minutes vs 157 ± 39 minutes; P = .63) were similar for groups A and B. Freedom from EII was significantly lower for group A compared with group B at 3 months (58% vs 80%; P = .002), 6 months (68% vs 85%; P = .04), and 12 months (70% vs 87%; P = .04) but not statistically significant at 24 months (85% vs 87%; P = .57). Freedom from EII-related reintervention at 24 months was significantly lower for group A compared with group B (82% vs 96%; P = .04). Patients in group B showed a significantly overall mean difference in aneurysm sac volume shrinkage compared with group A at 6 months (-11 ± 17 cm(3) vs -2 ± 14 cm(3); P < .01), 12 months (-18 ± 26 cm(3) vs -3 ± 32 cm(3); P = .02), and 24 months (-27 ± 25 cm(3) vs -5 ± 26 cm(3); P < .01). Patients in group C had the lowest EII rate compared with groups A and B (6 months, 5%; 12 months, 6%; 24 months, 0%) and no EII-related reintervention. CONCLUSIONS: This randomized study confirms that sac embolization during EVAR, using a sac volume-dependent dose of fibrin glue and coils, is a valid method to significantly reduce EII and its complications during early and midterm follow-up in patients considered at risk. Although further confirmatory studies are needed, the faster aneurysm sac volume shrinkage over time in patients who underwent embolization compared with standard EVAR may be a positive aspect influencing the lower EII rate also during long-term follow-up.

Remodeling of aortic aneurysm and aortic neck on follow-up after endovascular repair with suprarenal fixation.

OBJECTIVE: The objective of this study was to evaluate the remodeling of abdominal aortic aneurysms after endovascular aortic aneurysm repair (EVAR) with the Zenith (Cook Medical, Bloomington, Ind) device. METHODS: This was a retrospective study of anatomic data related to characteristics of the aortic neck diameter, iliac artery diameter, and aneurysm sac diameter collected during a clinical study of the Zenith device. RESULTS: In this study, 739 patients were observed for 2 years and 158 of them were observed for 5 years. The monthly rate of change for the neck diameter was more rapid in the early postoperative period (postoperative-30 days), with an expansion of 0.7 ± 0.09 mm/month, and during the third year of follow-up (24-36 months), with a monthly expansion rate of 0.10 ± 0.24 mm. The iliac arteries were also more prone to expansion during the first postoperative month (right iliac, 0.95 ± 0.08 mm/month; left iliac, 0.91 ± 0.08 mm/month) and in the next 6 months with a monthly expansion rate of 0.18 ± 0.02 mm and 0.21 ± 0.02 mm for the right and left iliac arteries, respectively. Remodeling of the aneurysm sac occurred mainly in the first postoperative year with a regression rate of 0.89 ± 0.05 mm/month between 1 and 6 months and 0.44 ± 0.04 mm/month for the second half of the year. The aneurysm sac regression rate dropped to 0.2 mm/month in the second postoperative year. Changes in the aortic neck diameter were statistically significant (P < .001) only at the 24- to 36-month postoperative interval. Changes in the aortic sac diameter were statistically significant (P < .001) at the 30-day to 6-month, 6- to 12-month, and 12- to 24-month intervals. Among patients who underwent reintervention, aortic sac expansion occurred primarily in the 24- to 36-month interval. CONCLUSIONS: Expansion of the aortic neck after EVAR for the Zenith endograft occurs mainly between 24 and 36 months; aortic aneurysm sac regression occurs more obviously at 1 to 12 months. Iliac arteries at the landing zone expand more rapidly in the first postoperative year. Late surveillance of EVAR patients is essential to avoid late complications after aortic remodeling.

Contemporary results of carotid endarterectomy in "normal-risk" patients from the Society for Vascular Surgery Vascular Registry.

OBJECTIVE: Acceptable complication rates after carotid endarterectomy (CEA) are drawn from decades-old data. The recent Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) demonstrated improved stroke and mortality outcomes after CEA compared with carotid artery stenting, with 30-day periprocedural CEA stroke rates of 3.2% and 1.4% for symptomatic (SX) and asymptomatic (ASX) patients, respectively. It is unclear whether these target rates can be attained in "normal-risk" (NR) patients experienced outside of the trial. This study was done to determine the contemporary results of CEA from a broader selection of NR patients. METHODS: The Society for Vascular Surgery (SVS) Vascular Registry was examined to determine in-hospital and 30-day event rates for NR, SX, and ASX patients undergoing CEA. NR was defined as patients without anatomic or physiologic risk factors as defined by SVS Carotid Practice Guidelines. Raw data and risk-adjusted rates of death, stroke, and myocardial infarction (MI) were compared between the ASX and SX cohorts. RESULTS: There were 3977 patients (1456 SX, 2521 ASX) available for comparison. The SX group consisted of more men (61.7% vs 57.0%; P = .0045) but reflected a lower proportion of white patients (91.3% vs 94.4%; P = .0002), with lower prevalence of coronary artery disease (P < .0001), prior MI (P < .0001), peripheral vascular disease (P = .0017), and hypertension (P = .029), although New York Heart Association grade >3 congestive heart failure was equally present in both groups (P = .30). Baseline stenosis >80% on duplex imaging was less prevalent among SX patients (54.2% vs 67.8%; P < .0001). Perioperative stroke rates were higher for SX patients in the hospital (2.8% vs 0.8%; P < .0001) and at 30 days (3.4% vs 1.0%; P < .0001), which contributed to the higher composite death, stroke, and MI rates in the hospital (3.6% vs 1.8; P = .0003) and at 30 days (4.5% vs 2.2%; P < .0001) observed in SX patients. After risk adjustment, the rate of stroke/death was greater among SX patients in the hospital (odds ratio, 2.05; 95% confidence interval, 1.18-3.58) although not at 30 days (odds ratio, 1.36; 95% confidence interval, 0.85-2.17). No in-hospital or 30-day differences were observed for death or MI by symptom status. CONCLUSIONS: The SVS Vascular Registry results for CEA in NR patients are similar by symptom status to those reported for CREST and may serve as a benchmark for comparing results of alternative therapies for treatment of carotid stenosis in NR patients outside of monitored clinical trials. The contemporary perioperative risk of stroke after CEA in NR patients continues to be higher for SX than for ASX patients.

Gender-specific 30-day outcomes after carotid endarterectomy and carotid artery stenting in the Society for Vascular Surgery Vascular Registry.

OBJECTIVE: Although the optimal treatment of carotid stenosis remains unclear, available data suggest that women have higher risk of adverse events after carotid revascularization. We used data from the Society for Vascular Surgery Vascular Registry to determine the effect of gender on outcomes after carotid endarterectomy (CEA) and carotid artery stenting (CAS). METHODS: There were 9865 patients (40.6% women) who underwent CEA (n = 6492) and CAS (n = 3373). The primary end point was a composite of death, stroke, and myocardial infarction at 30 days. RESULTS: There was no difference in age and ethnicity between genders, but men were more likely to be symptomatic (41.6% vs 38.6%; P < .003). There was a higher prevalence of hypertension and chronic obstructive pulmonary disease in women, whereas men had a higher prevalence of coronary artery disease, history of myocardial infarction, and smoking history. For disease etiology in CAS, restenosis was more common in women (28.7% vs 19.7%; P < .0001), and radiation was higher in men (6.2% vs 2.6%; P < .0001). Comparing by gender, there were no statistically significant differences in the primary end point for CEA (women, 4.07%; men, 4.06%) or CAS (women, 6.69%; men, 6.80%). There remains no difference after stratification by symptomatology and multivariate risk adjustment. CONCLUSIONS: In this large, real-world analysis, women and men demonstrated similar results after CEA or CAS. These data suggest that, contrary to previous reports, women do not have a higher risk of adverse events after carotid revascularization.

The influence of contralateral occlusion on results of carotid interventions from the Society for Vascular Surgery Vascular Registry.

OBJECTIVE: Data on the influence of contralateral carotid occlusion (CCO) on carotid endarterectomy (CEA) are conflicting and are absent for carotid artery stenting (CAS). This study evaluated the influence of CCO on CEA and CAS. METHODS: We evaluated patients with and without CCO in the Society for Vascular Surgery Vascular Registry. Primary outcome was a composite of periprocedural death, stroke, or myocardial infarction (MI) (major adverse cardiovascular events [MACE]) and its individual components. Further analysis was done to identify the influence, if any, of symptom status on outcomes. RESULTS: There were 1128 CAS and 666 CEA patients with CCO. CAS patients were more often symptomatic with a greater incidence of coronary artery disease, congestive heart failure, diabetes, chronic obstructive pulmonary disease, and New York Heart Association class >III. Absolute risk of periprocedural MACE (2.7% for CAS vs. 4.2% for CEA), death (1.1% for CAS vs. 0.7% for CEA), stroke (2.1% for CAS vs. 3.1% for CEA), and MI (0.3% for CAS vs. 0.6% for CEA) was statistically equivalent for both. This equivalence was maintained when patients with CCO were segregated according to symptom status and after adjusting for periprocedural risk. There were 16,646 patients without contralateral occlusion (5698 CAS; 10,948 CEA). Patients without contralateral occlusion with CEA have better outcomes in periprocedural MACE (1.8% for patients without contralateral occlusion vs 4.2% for patients with CCO), and stroke (1.1% for patients without contralateral occlusion vs. 3.1% for patients with CCO) (P < .0001 for both). In CAS patients, CCO did not significantly affect periprocedural MACE (3.2% for patients without contralateral occlusion vs. 2.7% for patients with CCO), death (0.8% for patients without contralateral occlusion vs. 1.0% for patients with CCO), stroke (2.3% for patients without contralateral occlusion vs. 2.1% for patients with CCO), or MI (0.6% for patients without contralateral occlusion vs. 0.3% for patients with CCO). In CEA patients, CCO increased MACE, primarily by increasing stroke rates in asymptomatic (0.7% vs. 2.0%; P = .0095) and symptomatic (1.7% vs. 4.9%; P = .0012) patients. CONCLUSIONS: Although CEA is preferred in patients without contralateral occlusion, regardless of symptom status, based on lower rates of periprocedural MACE, death, and stroke, the benefit of CEA is lost in patients with CCO because of increased stroke rates in CCO patients after CEA but not after CAS regardless of symptom status. The results of CAS and CEA in patients with CCO are equivalent and within acceptable American Heart Association guidelines.

"TCAR or nothing": the only options for some complex carotid stenosis.

Transcervical carotid artery revascularization has emerged as an alternative to carotid endarterectomy and transfemoral carotid artery stenting. We present four cases for which we believe transcervical carotid artery revascularization was the only option to treat the lesions. Each case presented with specific technical challenges that were overcome by intraoperative planning that allowed for safe deployment of the Enroute stent (Silk Road Medical) with resolution of each patient's stenosis.

Three Levels of Neural Control Contributing to Performance-stabilizing Synergies in Multi-finger Tasks.

We tested a hypothesis on force-stabilizing synergies during four-finger accurate force production at three levels: (1) The level of the reciprocal and coactivation commands, estimated as the referent coordinate and apparent stiffness of all four fingers combined; (2) The level of individual finger forces; and (3) The level of firing of individual motor units (MU). Young, healthy participants performed accurate four-finger force production at a comfortable, non-fatiguing level under visual feedback on the total force magnitude. Mechanical reflections of the reciprocal and coactivation commands were estimated using small, smooth finger perturbations applied by the "inverse piano" device. Firing frequencies of motor units in the flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC) were estimated using surface recording. Principal component analysis was used to identify robust MU groups (MU-modes) with parallel changes in the firing frequency. The framework of the uncontrolled manifold hypothesis was used to compute synergy indices in the spaces of referent coordinate and apparent stiffness, finger forces, and MU-mode magnitudes. Force-stabilizing synergies were seen at all three levels. They were present in the MU-mode spaces defined for MUs in FDS, in EDC, and pooled over both muscles. No effects of hand dominance were seen. The synergy indices defined at different levels of analysis showed no correlations across the participants. The findings are interpreted within the theory of control with spatial referent coordinates for the effectors. We conclude that force stabilization gets contributions from three levels of neural control, likely associated with cortical, subcortical, and spinal circuitry.

Prospective, Multi-center, Single-Arm Study of the Auryon Laser System for Treatment of Below-the-Knee Arteries in Patients With Chronic Limb-Threatening Ischemia: 30-Day Results of the Auryon BTK.

The 355 nm Auryon laser (AngioDynamics, Inc., Latham, New York) has been shown to be effective and safe in treating various morphology lesions in the femoropopliteal arteries. There are limited data on the Auryon laser in treating below-the-knee (BTK) arteries in patients with chronic limb-threatening ischemia. We present the 30-day efficacy and safety findings from the ongoing Auryon BTK study. Patients with chronic limb-threatening ischemia were prospectively enrolled in the Auryon BTK study between March 2022 and February 2023 in 4 US centers after obtaining written informed consent. The primary safety end point included major adverse limb events + postoperative death at 30 days, defined as a composite of all-cause death, major amputation, and target vessel revascularization. Demographic, procedural, angiographic, and outcome data were collected. A total of 60 patients (61 lesions) were treated. The mean age was 74.6 ± 10.3 years, with 65.0% men, 58.3% with diabetes, 43.3% Rutherford Becker (RB) IV, and 56.7% RB V. Of the 61 lesions, 59% had severe calcification, 31.1% were chronic total occlusions, and 90.2% were de novo disease. The baseline diameter stenosis was 80.2 ± 16.4%, after laser 57.4 ± 21.7%, and after final treatment 24.0 ± 23.1% (p <0.0050). The primary performance end point showed a procedure success rate of 37 of 68 (63.8%). Bailout stenting occurred in 1 of 61 lesions (1.6%). The RB category was 100% RB IV or higher at baseline versus 35.3% at 30 days. At 30 days, there was no target vessel revascularization and the patency was 88.9% (Peak Systolic Velocity Ratio (PSVR) ≤2.4). In conclusion, the Auryon laser is safe and relatively effective in treating BTK lesions with minimal complications.

Debate: whether fenestrated endografts should be limited to a small number of specialized centers.

Until fairly recently, experience with advanced endovascular technologies, including fenestrated endovascular repair (FEVAR), has been limited to a relatively small number of practitioners worldwide. Excellent outcomes have been achieved by these accomplished surgeons who, at least initially, have primarily used custom-made devices constructed by a single endograft manufacturer. Access to this technology has been limited by the skills necessary for such procedures and by the customization process with industry partners. However, several issues are changing rapidly with FEVAR. Increasing numbers of surgeons now have the necessary endovascular skills, and off-the-shelf endografts from several manufacturers have become, or are becoming, available. Also, the regulatory landscape is changing with device approval in the United States. Surgeons and patients alike are anticipating the widespread adoption of this advanced technology that will surely benefit increasing numbers of patients. Or will it? Will widespread adoption in a larger number of smaller-volume hospitals, by less experienced surgeons, result in poor patient outcomes, or will excellent results continue with more patients benefitting from these technologic advances? These are important questions to ask before such adoption and are the subject of this debate.

Results of elective and emergency endovascular repairs of popliteal artery aneurysms.

OBJECTIVE: Endovascular repair has emerged as a treatment option for popliteal artery aneurysms. Our goal was to analyze outcomes of elective and emergency endovascular popliteal artery aneurysm repair (EVPAR). METHODS: This was a retrospective review of clinical data of patients treated with EVPAR at our institution between 2004 and 2010. Stent-related complications, patency, outcome limb salvage, and survival were evaluated and analyzed. RESULTS: EVPAR was performed in 31 limbs of 25 patients (mean age, 81 years; range, 65-89 years). Repair was elective in 19 limbs (61%) and emergent in 12 (39%). One aneurysm ruptured and 11 presented with acute thrombosis. All 11 underwent thrombolysis before EVPAR. Patients were implanted with a mean of 2.1 Viabahn stent grafts (range, 1-4). Ten procedures (32%) were performed percutaneously and 21 by femoral cutdown. Technical success was 97%. Overall 30-day mortality was 6.4%, with 0% in the elective group, and 16.7% in the emergent group (P = .14). Early complications included graft thrombosis in two limbs (6.4%) and hematoma in four (13%), all after percutaneous repair. Myocardial infarction and thrombolysis-associated intracranial hemorrhage occurred in one patient each (3.2%). The 30-day primary and secondary patencies were 93.6% and 96.7%, respectively, and were 100% in the elective group and 83.3% and 91.6%, respectively, for the emergent group. Mean follow-up was 21.3 months (range, 1-75 months). Primary patency at 1 year was 86% (95% for elective, 69% for emergent; P = .56), secondary patency at the same time was 91% (elective, 100%; emergent, 91%). One-year limb salvage was 97%. Two-year survival was 91% for the elective group and 73% for the emergent group (P = .15). Five stent occlusions were encountered after 30 days, four in the elective group. Four underwent successful reintervention, two had bypass, and two had thrombolysis, followed by angioplasty. The fifth patient was asymptomatic and nonambulatory and remains under observation. Stent graft infolding occurred in one limb (3.2%), with no clinical sequelae. No stent migration or separation was observed. One stent fracture was noted in an asymptomatic patient. Three (10%) type II endoleaks were detected but none had aneurysm expansion. One (3.2%) type I endoleak was treated percutaneously with placement of an additional stent graft. Overall, major adverse events, including death, graft occlusion with or without reoperation, or reoperation for endoleak or stent infolding occurred after 11 procedures (35.5%). On univariate analysis, no factors predicted stent failure, including runoff, antiplatelet therapy, emergency repair, number of stents implanted, heparin bonding of the stent, or degree of stent oversizing. CONCLUSIONS: These results support elective EVPAR in anatomically suitable patients with increased risk for open repair; however, major adverse events after EVPAR, mainly after emergency repairs, are frequent. A prospective randomized multicenter study to justify EVPAR in the emergent setting is warranted.

Role of aneurysm sac embolization during endovascular aneurysm repair in the prevention of type II endoleak-related complications.

OBJECTIVE: The goal of this study was to evaluate the role of intraoperative aneurysm sac embolization during endovascular aneurysm repair (EVAR) using a standard dose of coils and fibrin glue in the prevention of type II endoleak (EII). METHODS: Two groups were compared: 83 patients underwent standard EVAR during the period 2008-2009 (group A) and 79 patients underwent EVAR during the period 2010-2011 (group B). Computed tomography scans were evaluated with Osirix Pro 4.0 software to obtain aneurysm sac volume. EII rates at the first computed tomography scan follow-up, as well as midterm freedom from EII and freedom from related reintervention, were compared. Preoperative number of patent aortic side branches (inferior mesenteric artery, lumbar arteries, accessory renal arteries), sac thrombus, and sac volume were evaluated for their association with EII in the two groups using multiple logistic regressions. RESULTS: Patient characteristics, Society for Vascular Surgery comorbidity scores (0.85 ± 0.44 vs 0.82 ± 0.46; P = .96), and operative time (185 ± 52 vs 179 ± 49; P = .92) were similar for groups A and B. The first computed tomography scan (≤3 months) revealed a significantly larger number of EIIs in group A than in group B (23% vs 10%; P = .02). Spontaneous EII resolution occurred in 65% of patients in group A and in 79% in group B (P = 1.0), whereas sac volume increased in 25% and 10% (P = .63) of cases, respectively. At 18 months (range, 6 months to 4.4 years), overall mean differences in sac volume shrinkage (27 ± 12 cm(3) vs 25 ± 12 cm(3); P = .19) and freedom from EII (92% vs 96%; P = .33) were similar, whereas freedom from reintervention was significantly lower in group A (93% vs 99%; P = .03) than in group B. Multivariate analysis showed preoperative aneurysm sac volume >125 cm(3) to be the only independent significant predictor of EII (odds ratio, 4.0; 95% confidence interval, 1.5-10.5; P = .005). CONCLUSIONS: Although further confirmatory studies are needed, sac embolization during EVAR may be a valid approach to preventing EII and its complications during short- and midterm follow-up. More aggressive intraoperative embolization should be considered for patients with a preoperative aneurysm sac volume >125 cm(3).