Automated Electronic Frailty Index is Associated with Non-home Discharge in Patients Undergoing Open Revascularization for Peripheral Vascular Disease.

BACKGROUND: Frailty is associated with adverse surgical outcomes including post-operative complications, needs for post-acute care, and mortality. While multiple frailty screening tools exist, most are time and resource intensive. Here we examine the association of an automated electronic frailty index (eFI), derived from routine data in the Electronic Health Record (EHR), with outcomes in vascular surgery patients undergoing open, lower extremity revascularization. METHODS: A retrospective analysis at a single academic medical center from 2015 to 2019 was completed. Information extracted from the EHR included demographics, eFI, comorbidity, and procedure type. Frailty status was defined as fit (eFI≤0.10), pre-frail (0.100.21). Outcomes included length of stay (LOS), 30-day readmission, and non-home discharge. RESULTS: We included 295 patients (mean age 65.9 years; 31% female), with the majority classified as pre-frail (57%) or frail (32%). Frail patients exhibited a higher degree of comorbidity and were more likely to be classified as American Society of Anesthesiologist class IV (frail: 46%, pre-frail: 27%, and fit: 18%, P = 0.0012). There were no statistically significant differences in procedure type, LOS, or 30-day readmissions based on eFI. Frail patients were more likely to expire in the hospital or be discharged to an acute care facility (31%) compared to pre-frail (14%) and fit patients (15%, P = 0.002). Adjusting for comorbidity, risk of non-home discharge was higher comparing frail to pre-frail patients (OR 3.01, 95% CI 1.40-6.48). DISCUSSION: Frail patients, based on eFI, undergoing elective, open, lower extremity revascularization were twice as likely to not be discharged home.

A Single-Center Experience with Forearm Arteriovenous Loop Grafts for Hemodialysis.

BACKGROUND: Autogenous arteriovenous fistula (AVF) remains the standard of hemodialysis (HD) access; however, it cannot be reasonably obtained in all patients. For patients with contraindications to AVFs, prosthetic arteriovenous graft (AVG) remains an alternative. AVGs are plagued by high failure rates; however, there is a paucity of literature examining this. This study aims to examine a single-center review of outcomes of forearm loop AVGs in patients requiring HD access. METHODS: A single institution, retrospective chart review was completed from 2012 to 2019, including demographics, end-stage renal disease etiology, brachial vessel diameters, and comorbidities. Logistic regression and Cox proportional hazard models were evaluated. Outcomes were defined as primary patency (time elapsed from graft creation until it was utilized as the patient's primary access), primary-assisted patency (time from primary access to intervention to maintain patency), and functional patency (time from graft placement until graft failure). Additionally, multinomial regression models were used to evaluate associations with categorical number of required interventions. RESULTS: Ninety-eight patients [mean age 61.8 (13.9) years, 42.9% female] were identified as having brachial artery to brachial vein AVG creation during the study period, of which 75% achieved primary patency. Primary-assisted patency was 0.36 [standard error (SE) 0.07] at 6 months and 0.12 (SE 0.05) at 1 year. Functional patency was 0.75 (SE 0.07) at 6 months and 0.43 (SE 0.09) at 1 year. No association between preoperative vessel diameters and primary-assisted or functional patency was observed. Interestingly, there was a significant negative association between previous ipsilateral access and achievement of primary patency with a 60% decrease in odds of achieving primary patency in patients with previous ipsilateral access [odds ratio 0.4, 95% confidence interval (CI) 0.1-0.9, P = 0.03]. There was also noted to be a significant association between the presence of an ipsilateral catheter and increased risk of subsequent abandonment of the AVG (hazard ratio 2.6, 95% CI 1.1-5.8, P = 0.02). CONCLUSIONS: Prosthetic forearm loop AVGs remain hindered in their utility as they show high rates of graft failure within a year of creation. A significant patient-specific factor leading to this was not clearly demonstrated. As guidelines change regarding the nature of dialysis access for patients on HD, these results draw into question the utility of prosthetic forearm loop grafts in patients requiring long-term HD access.

Arteriovenous Fistula Versus Graft Access Strategy in Older Adults Receiving Hemodialysis: A Pilot Randomized Trial.

BACKGROUND: It is unclear whether surgical placement of an arteriovenous (AV) fistula (AVF) confers substantial clinical benefits over an AV graft (AVG) in older adults with end-stage kidney disease (ESKD). We report vascular access outcomes of a pilot clinical trial. STUDY DESIGN: Pilot randomized parallel-group open-label trial. SETTING & PARTICIPANTS: Patients 65 years and older with ESKD and no prior AV access receiving maintenance hemodialysis through a tunneled central venous catheter referred for AV access placement by their treating nephrologist. INTERVENTION: Participants were randomly assigned in a 1:1 ratio to surgical placement of an AVG or AVF. OUTCOMES: Index AV access primary failure, successful cannulation, adjuvant interventions and infections. RESULTS: Of 122 older adults receiving hemodialysis and no prior AV access surgery, 24% died before (n = 18) or were too sick for (n = 11) referral for a permanent AV access. Of 46 eligible patients, 36 (78%) consented and were randomly assigned to AVG (n = 18) and AVF (n = 18) placement, of whom 13 (72%) and 16 (89%) underwent index AV access surgical placement, respectively. At a median follow-up of 321.0 days, primary AV access failure was noted in 31% in each group. The proportion of patients with successful cannulation was 62% (8 of 13) in the AVG and 50% (8 of 16) in the AVF group; median times to successful cannulation were 75.0 and 113.5 days, respectively. Endovascular procedures were recorded in 38% and 44%, and surgical reinterventions, in 23% and 25%, respectively. AV access infection was seen in 3 (23%) and 2 (13%) patients, respectively. LIMITATIONS: Small sample size precludes statistical inference. CONCLUSIONS: Almost one-quarter of older adults with incident ESKD and a central venous catheter as primary access were not referred for AV access placement due to medical reasons. Based on these limited results, there is little reason to favor either an AVF or AVG in this population until results from a larger randomized clinical trial become available. FUNDING: Government funding to an author (Dr Murea is supported by National Institutes of Health∖National Institute on Aging grant 1R03 AG060178-01). TRIAL REGISTRATION: NCT03545113.

Evaluation of Neuropathy, Glycemic Control, and Revascularization as Risk Factors for Future Lower Extremity Amputation among Diabetic Patients.

BACKGROUND: Diabetes mellitus is a major risk factor for progression to lower extremity amputation (LEA) due to progressive neuropathy and glycemia-induced vasculopathy. In this study, we evaluated risk factors for incident LEA type 2 diabetics during a randomized controlled trial and extended post-trial follow-up. METHODS: The Action to Control Cardiovascular Risk in Diabetes trial randomized 10,251 type 2 diabetics to intensive glycemic control (Hemoglobin A1c (HbA1c) target <6.0%) versus standard glycemic control (HbA1c target 7.0-7.9%). Using backward elimination logistic regression models, we examined relationships between neuropathy using the Michigan Neuropathy Screening Instrument (MNSI) and glycemic control and incident LEA during the clinical trial and subsequent follow-up. RESULTS: 9,746 patients were followed for a mean of 7.9 +/-3.1 (median 8.9) years after randomization. Ninety-eight (1%) participants underwent an incident LEA during the trial or post-trial follow-up period. Baseline demographics and traditional risk factors were examined by incident amputation status. Multivariable models revealed that abnormal 10 gm filament test (HR 4.50, 95% CI 2.92-6.95, P < 0.0001), presence of ulceration (HR 4.22, 95% CI 1.65-10.8, P = 0.0004), abnormal appearance on foot examination (HR 4.75, 95% CI 2.30-9.83, P < 0.0001), and mean postrandomization HbA1c (HR 1.65, 95% CI 1.35-2.00, P < 0.0001) were strongly predictive of LEA when accounting for other common risk factors for amputation. CONCLUSIONS: In this post hoc analysis of a large randomized controlled population of diabetic patients, we found that components of the MNSI score including presence of ulceration, abnormal appearance of the foot, and 10 gm filament monofilament scoring were strongly predictive of LEA. This adds a valuable clinical tool in the risk stratification of diabetic patients for LEA.

A randomized pilot study to evaluate graft versus fistula vascular access strategy in older patients with advanced kidney disease: results of a feasibility study.

BACKGROUND: Although older adults encompass almost half of patients with advanced chronic kidney disease, it remains unclear which long-term hemodialysis vascular access type, arteriovenous fistula or arteriovenous graft, is optimal with respect to effectiveness and patient satisfaction. Clinical outcomes based on the initial AV access type have not been evaluated in randomized controlled trials. This pilot study tested the feasibility of randomizing older adults with advanced kidney disease to initial arteriovenous fistula versus graft vascular access surgery. METHODS: Patients 65 years or older with pre-dialysis chronic kidney disease or incident end-stage kidney disease and no prior arteriovenous vascular access intervention were randomized in a 1:1 ratio to undergo surgical placement of a fistula or a graft after providing informed consent. Trial feasibility was evaluated as (i) recruitment of ≥ 70% of eligible participants, (ii) ≥ 50 to 70% of participants undergo placement of index arteriovenous access within 90 to 180 days of enrollment, respectively, (iii) ≥ 80% adherence to study-related assessments, and (iv) ≥ 70% of participants who underwent index arteriovenous access placement will have a follow-up duration of ≥ 12 months after index surgery date. RESULTS: Between September 2018 and October 2019, 81% (44/54) of eligible participants consented and were enrolled in the study; 11 had pre-dialysis chronic kidney disease, and 33 had incident or prevalent end-stage kidney disease. After randomization, 100% (21/21) assigned to arteriovenous fistula surgery and 78% (18/23) assigned to arteriovenous graft surgery underwent index arteriovenous access placement within a median (1st, 3rd quartile) of 5.0 (1.0, 14.0) days and 13.0 (5.0, 44.3) days, respectively, after referral to vascular surgery. The completion rates for study-specific assessments ranged between 40.0 and 88.6%. At median follow-up of 215.0 days, 5 participants expired, 7 completed 12 months of follow-up, and 29 are actively being followed. Assessments of grip strength, functional independence, and vascular access satisfaction were completed by > 85% of patients who reached pre-specified post-operative assessment time point. CONCLUSIONS: Results from this study reveal it is feasible to enroll and randomize older adults with advanced kidney disease to one of two different arteriovenous vascular access placement surgeries. The study can progress with minor protocol adjustments to a multisite clinical trial. TRIAL REGISTRATION: Clinical Trials ID, NCT03545113.

Vascular access for hemodialysis: A perpetual challenge.

Vascular access for hemodialysis has a long and rich history. This article highlights major innovations and milestones in the history of angioaccess for hemodialysis. Advances in achievement of lasting hemodialysis access, swift access transition, immediate and sustaining access to vascular space built the momentum at different turning points of access history and shaped the current practice of vascular access strategy. In the present era, absent of large-scale clinical trials to validate practice, the ever-changing demographic and comorbidity makeup of the dialysis population pushes against stereotypical angioaccess goals. The future of hemodialysis vascular access would benefit from proper randomized clinical trials and acclimatization to clinical contexts.

A randomized pilot study comparing graft-first to fistula-first strategies in older patients with incident end-stage kidney disease: Clinical rationale and study design.

Timely placement of an arteriovenous (AV) vascular access (native AV fistula [AVF] or prosthetic AV graft [AVG]) is necessary to limit the use of tunneled central venous catheters (TCVC) in patients with end-stage kidney disease (ESKD) treated with hemodialysis (HD). National guidelines recommend placement of AVF as the AV access of first choice in all patients to improve patient survival. The benefits of AVF over AVG are less certain in the older adults, as age-related biological changes independently modulate patient outcomes. This manuscript describes the rationale, study design and protocol for a randomized controlled pilot study of the feasibility and effects of AVG-first access placement in older adults with no prior AV access surgery. Fifty patients age ≥65 years, with incident ESKD on HD via TCVC or advanced kidney disease facing imminent HD initiation, and suitable upper extremity vasculature for initial placement of an AVF or AVG, will be randomly assigned to receive either an upper extremity AVG-first (intervention) or AVF-first (comparator) access. The study will establish feasibility of randomizing older adults to the two types of AV access surgery, evaluate relationships between measurements of preoperative physical function and vascular access development, compare vascular access outcomes between groups, and gather longitudinal assessments of upper extremity muscle strength, gait speed, performance of activities of daily living, and patient satisfaction with their vascular access and quality of life. Results will assist with the planning of a larger, multicenter trial assessing patient-centered outcomes.

Effect of Intensive Glycemic Control on Risk of Lower Extremity Amputation.

BACKGROUND: Diabetes mellitus is a major risk factor for peripheral arterial disease and lower extremity amputation (LEA). We evaluated the effects of intensive glucose control (IGC) on risk of LEA in patients with type 2 diabetes during a randomized-controlled multicenter trial. STUDY DESIGN: The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial randomized patients with type 2 diabetes to IGC (HbA1c target < 6.0%) or standard glycemic control (SGC; HbA1c target 7.0% to 7.9%). Using analysis of mean HbA1c, we examined relationships between glycemic control and incident/recurrent LEA during the clinical trial/follow-up. RESULTS: Mean post-randomization HbA1c over the course of the trial and post-trial follow-up was 7.3% ± 0.9% (6.8% ± 0.8% in the IGC arm, 7.7% ± 0.7% in the SGC arm). There were 124 participants who had at least 1 LEA during the study period; 73 were randomized to the SGC arm and 51 to the IGC arm (p = 0.049). Randomization to IGC was associated with decreased LEA rate (HR 0.69, 95% CI 0.483 to 0.987, p = 0.042). In multivariable models, mean HbA1c was a powerful predictor of LEA (HR 2.07 per 1% increase in HbA1c, 95% CI 1.67 to 2.57, p < 0.0001). Post-randomization mean HbA1c remained a strong predictor of LEA after controlling for other important covariates and competing risk of death (HR 1.94 per 1% increase in HbA1c, 95% CI 1.52 to 2.46, p < 0.0001). CONCLUSIONS: In patients with type 2 diabetes, IGC was associated with a reduction in the risk for LEA. After 3.7 years of IGC, there was an enduring protective effect against LEA. Improved glycemic control was a strong predictor of decreased risk for subsequent LEA. This study suggests that tight glycemic control, even over a short time period, has potential to reduce risk of limb loss.

The natural history of class I primate alcohol dehydrogenases includes gene duplication, gene loss, and gene conversion.

BACKGROUND: Gene duplication is a source of molecular innovation throughout evolution. However, even with massive amounts of genome sequence data, correlating gene duplication with speciation and other events in natural history can be difficult. This is especially true in its most interesting cases, where rapid and multiple duplications are likely to reflect adaptation to rapidly changing environments and life styles. This may be so for Class I of alcohol dehydrogenases (ADH1s), where multiple duplications occurred in primate lineages in Old and New World monkeys (OWMs and NWMs) and hominoids. METHODOLOGY/PRINCIPAL FINDINGS: To build a preferred model for the natural history of ADH1s, we determined the sequences of nine new ADH1 genes, finding for the first time multiple paralogs in various prosimians (lemurs, strepsirhines). Database mining then identified novel ADH1 paralogs in both macaque (an OWM) and marmoset (a NWM). These were used with the previously identified human paralogs to resolve controversies relating to dates of duplication and gene conversion in the ADH1 family. Central to these controversies are differences in the topologies of trees generated from exonic (coding) sequences and intronic sequences. CONCLUSIONS/SIGNIFICANCE: We provide evidence that gene conversions are the primary source of difference, using molecular clock dating of duplications and analyses of microinsertions and deletions (micro-indels). The tree topology inferred from intron sequences appear to more correctly represent the natural history of ADH1s, with the ADH1 paralogs in platyrrhines (NWMs) and catarrhines (OWMs and hominoids) having arisen by duplications shortly predating the divergence of OWMs and NWMs. We also conclude that paralogs in lemurs arose independently. Finally, we identify errors in database interpretation as the source of controversies concerning gene conversion. These analyses provide a model for the natural history of ADH1s that posits four ADH1 paralogs in the ancestor of Catarrhine and Platyrrhine primates, followed by the loss of an ADH1 paralog in the human lineage.

A personalized sensor-controlled microstimulator system for arm rehabilitation poststroke. Part 1: System architecture.

OBJECTIVES: For rehabilitation of the poststroke upper limb in seven subjects, an external sensor-based system controls the timing of five to seven microstimulators implanted near radial nerve branches or their motor points to sequentially extend the elbow, wrist, and fingers with thumb extension and abduction, enabled at the subject's own pace. We hypothesize this system will support sequential activation of affected upper limb muscles intended to improve functional recovery. MATERIALS AND METHODS: Presented here is a personalized sensor-controlled stimulation system, including its architecture, sensor design, and testing of equipment specific to this study, including coils and sensors. RESULTS: All electrical and magnetic tests, and safety tests per International Electrotechnical Commission 60601-1 passed. One sensor type displayed a vulnerability to drop. CONCLUSIONS: The new control system tested safe, met requirements, and allowed each subject to activate the system at their own pace, making the rehabilitation process more acceptable and efficient.

A personalized sensor-controlled microstimulator system for arm rehabilitation poststroke. Part 2: Objective outcomes and patients' perspectives.

OBJECTIVE: To examine the effect of home-based electrical stimulation using closed-loop control of implanted microstimulators on upper limb function and impairment, and subjects' perception of the system. MATERIALS AND METHODS: Six subjects with poststroke hemiparesis, and reduced upper limb function, who had taken part in Phase 1 of the study, were fitted with a personalized closed-loop control system (Phase 2) and used it at home during performance of functional tasks for 12 weeks (Phase 3). Main outcome measures were: Action Research Arm Test (ARAT), Fugl-Meyer upper limb assessment (FMA), and motor control (Tracking Index). Subjects' perception of the system was assessed in a structured interview. RESULTS: Improvement in ARAT (p=0.05), FMA (p=0.02), and Tracking Index (p=0.03) during Phase 3. Five subjects said using the system had changed their lives and improved their function, all performed functional tasks with the system, but external components were inconvenient. CONCLUSIONS: Closed-loop control improved in function. Subjective assessment identified that the external sensors were effective.

Accuracy of duplex sonography scans after renal artery stenting.

PURPOSE: Reports of duplex sonography scan criteria for recurrent renal arterial (RA) stenosis after endoluminal stenting have suggested that criteria for native arteries may overestimate recurrent disease. This retrospective report examines the utility of renal duplex sonography (RDS) scans to define the presence of significant (ie, ≥ 60%) renovascular disease (RVD) after percutaneous angioplasty and endoluminal stenting (PTAS). METHODS: Demographic, duplex, and angiographic data were reviewed and compared. RDS was obtained. Peak systolic velocities (PSV) were obtained after PTAS from multiple sites along the main RA from both anterior and flank approaches. Comparable images from digital subtraction angiography were independently examined for restenosis. Percent diameter stenosis was determined from the site of maximal stenosis compared with the normal RA distal to the stent. Sensitivity and specificity were estimated and 95% confidence intervals (CIs) were computed after adjusting for within patient "clustering" of observations applying native RA RDS criteria using angiography as the gold standard. Receiver operating characteristic (ROC) curves were used to estimate the optimal RDS values for recurrent stenosis. RESULTS: From October 2003 to June 2009, 49 patients had angiographic imaging after PTAS. There were 30 patients (18 women, 12 men; mean age, 71 ± 9 years) provided technically adequate paired angiographic and RDS assessment after PTAS for 66 RAs. Paired analysis was performed for 23 RAs after primary PTAS and 43 RAs after secondary treatment. The prevalence of significant restenosis was 35% (23 of 66 RAs). RAs with greater than 60% diameter restenosis had higher peak systolic velocity (PSV) compared to those without (2.48 ± 1.15 millisecond vs 1.44 ± 0.58 millisecond; P < .001). Compared to angiography, RA-PSV ≥ 1.8 millisecond with distal RA turbulence demonstrated a sensitivity of 73% (95% CI, 54%, 91%), specificity of 80% (95% CI, 67%, 93%), and an overall accuracy of 77% (95% CI, 67%, 88%) with a positive predictive value of 64% (95% CI, 46%, 82%). Optimal RDS value estimated by ROC curve resulted in RA-PSV of 2.5 millisecond which was associated with a sensitivity of 59% (95% CI, 36%, 82%), specificity of 95% (95% CI, 89%, 100%), an accuracy of 83% (95% CI, 74%, 92%), and a positive predictive value of 87% (95% CI, 68%, 100%). CONCLUSION: Renal duplex sonography has utility to detect significant restenosis after PTAS. RDS criteria for significant native RA stenosis compare favorably with optimal RDS criteria for restenosis estimated by ROC curves.

Trends in vena caval interruption.

OBJECTIVE: This study examined the national use of vena cava filters (VCFs) from 1998 to 2005. METHODS: Methods for complex surveys were used to examine hospital discharge data from the Nationwide Inpatient Sample (NIS) to determine the use of VCFs for the years 1998 to 2005. VCF placement in the absence of deep venous thrombosis (DVT) or pulmonary embolus (PE) was categorized as prophylactic. RESULTS: During the study period, the estimated rate of hospitalizations per year with a diagnosis of DVT (odds ratio [OR], 1.025; 95% confidence interval [CI], 1.019-1.032; P < .01) or PE (OR, 1.076; 95% CI, 1.069-1.083; P < .01) rose significantly. The estimated weighted frequency of VCF placement increased from 52,860 procedures in 1998 to 104,114 procedures in 2005 (0.15% and 0.27% of all discharges, respectively), representing an 80% increase. VCF placement significantly increased during hospitalizations with any diagnosis of DVT or PE, or both, and no DVT or PE (P < .01 for each). Logistic regression models revealed that the rate of prophylactic VCF placement increased at a significantly higher rate than VCF placement associated with DVT or PE (157% vs 42%; P < .01), after adjusting for age, gender, and hospital characteristics. Prophylactic VCF placement in the setting of morbid obesity (P < .01) and head injury (P = .03) rose significantly over time. CONCLUSIONS: From 1998 to 2005, the estimated rates of prophylactic VCF placement increased at a significantly higher rate than VCF placement in the setting of DVT or PE. Significant increases in the use of prophylactic VCFs were seen in the setting of morbid obesity and head injury.

Atherosclerotic renovascular disease among hypertensive adults.

PURPOSE: This report describes the change in atherosclerotic renovascular disease (AS-RVD) among hypertensive adults referred for renal duplex sonography (RDS) scan. METHODS: From Oct 1993 through July 2008, 20,994 patients had RDS at our center. A total of 434 hypertensive patients with two or more RDS exams without intervention comprised the study cohort. Patient demographics (blood pressures, medications, serum creatinine levels, and data from RDS) were collected. Analyses of longitudinal changes in Doppler scan parameters, blood pressures, and renal function were performed by fitting linear growth-curve models. After confirming the linearity of change in Doppler scan parameters among patients with variable number of studies, estimates of mean slopes were calculated using maximum likelihood techniques. For changes in renal function, quadratic growth curves were required to describe longitudinal change. RESULTS: A total of 434 subjects (212 men [49%] and 222 women [51%]; mean age, 64.6 +/- 12.2 years) provided 1351 studies (mean, 3.2 +/- 2.4; range, 2 to 18) for 863 kidneys over a mean follow-up of 34.4 +/- 25.1 months. At baseline, 20.6% of kidneys demonstrated hemodynamically significant stenosis. On follow-up, 72 kidneys (9.1%) demonstrated anatomic progression of disease. A total of 54 kidneys (6.9%) progressed to significant stenosis and 18 (2.3%) progressed to occlusion. Controlling for progression of disease, baseline renal artery status demonstrated a strong association with baseline kidney length (P = .0006). Significant annualized change in renal length was observed (cm change/year +/- standard error of the mean [SEM]: 0.042 +/- 0.011; P = .0002) among both kidneys with and without critical disease at baseline, however, decline in length was significantly greater among kidneys exhibiting progression of renovascular disease (-0.152 +/- 0.028 cm/year; comparison of slopes between groups P = .0005). In the absence of progression, the presence or absence of critical renal artery stenosis at baseline did not affect the rate of decline in renal length. Fitted models for the natural log transform of serum creatinine demonstrated a significant increase during follow-up (P < .0001). No association was observed between change in serum creatinine and baseline renovascular disease status, or its progression. CONCLUSION: A total of 32% of hypertensive adults referred for RDS demonstrated hemodynamically significant renal artery stenosis. Regardless of the presence or absence of baseline disease, a small percentage of patients demonstrated anatomic progression of AS-RVD. A total of 9.1% demonstrated anatomic progression and 2.3% progressed to occlusion. Although anatomic progression of AS-RVD was associated with an increased rate of decline in renal length, progression did not predict a decline in excretory renal function. Intervention for AS-RVD should be selective and reserved for strict indications.

Poststroke upper-limb rehabilitation using 5 to 7 inserted microstimulators: implant procedure, safety, and efficacy for restoration of function.

OBJECTIVE: To investigate the feasibility of implanting microstimulators to deliver programmed nerve stimulation for sequenced muscle activation to recover arm-hand functions. DESIGN: By using a minimally invasive procedure and local anesthesia, 5 to 7 microstimulators can be safely and comfortably implanted adjacent to targeted radial nerve branches in the arm and forearm of 7 subjects with poststroke paresis. The microstimulators' position should remain stable with no tissue infection and can be programmed to produce effective personalized functional muscle activity with no discomfort for a preliminary 12-week study. Clinical testing, before and after the study, is reported in the accompanying study. SETTING: Microstimulator implantations in a sterile operating room. PARTICIPANTS: Seven adults, with poststroke hemiparesis of 12 months or more. INTERVENTION: Under local anesthesia, a stimulating probe was inserted to identify radial nerve branches. Microstimulators were inserted by using an introducer and were retrievable for 6 days by attached suture. Each device was powered via a radiofrequency link from 2 external cuff coils connected to a control unit. MAIN OUTCOME MEASURES: To achieve low threshold values at the target sites with minimal implant discomfort. Microstimulators and external equipment were monitored over 12 weeks of exercise. RESULTS: Seven subjects were implanted with 41 microstimulators, 5 to 7 per subject, taking 3.5 to 6 hours. Implantation pain levels were 20% more than anticipated. No infections or microstimulator failures occurred. Mean nerve thresholds ranged between 4.0 to 7.7 microcoulomb/cm(2)/phase over 90 days, indicating that cathodes were within 2 to 4 mm of target sites. In 1 subject, 2 additional microstimulators were inserted. CONCLUSIONS: Microstimulators were safely implanted with no infection or failure. The system was reliable and programmed effectively to perform exercises at home for functional restoration.

Therapeutic effectiveness of electric stimulation of the upper-limb poststroke using implanted microstimulators.

OBJECTIVE: To investigate the therapeutic effect of functional exercise augmented by programmable implanted microstimulators on arm and hand function. DESIGN: Before and after study. SETTING: Implantation was performed in a neurosurgery unit, systems were programmed, and tests were conducted in a university laboratory and subjects exercised at home. PARTICIPANTS: Hemiparetic subjects (N=7) with reduced upper-limb function who were at least 12 months poststroke were recruited from the community. No subjects withdrew. INTERVENTION: Microstimulators were implanted into the arms and forearms to activate elbow, wrist, and finger extension, and thumb abduction. After training and programming of the system, subjects underwent 12 weeks of functional home-based exercise with stimulation. MAIN OUTCOME MEASURES: The primary functional measure was the Action Research Arm Test (ARAT). Impairment measures included upper-limb Fugl-Meyer Assessment (FMA) and tests of motor control (tracking index), spasticity (electromyography stretch index) strength, and active range of motion (AROM). The assessor was not blinded, but scores were validated by an independent blinded observer. RESULTS: All subjects were able to perform functional activities at home by using the system. Compliance was excellent, and there were no serious adverse events. Statistically significant improvements were measured (P<.05) in the tracking index (57.3 degrees(2)+/-48.65 degrees(2)), FMA score (6.3+/-3.59), wrist-extensor strength (5.5+/-4.37 N), and wrist AROM (19.3 degrees +/-18.96 degrees). The mean improvement in ARAT score +/- SD of 4.9+/-7.89 was not statistically significant. CONCLUSIONS: This study has shown the feasibility of a programmable implanted microstimulator system used at home to perform functional exercises and a reduction in impairment after 12 weeks.

Reliability of inclinometer and goniometric measurements of hip extension flexibility using the modified Thomas test.

Our objectives were to examine interrater reliability for inclinometer and goniometric measurements of hip extension flexibility and the intra- and interrater reliability between instruments when measuring hip extension flexibility with the modified Thomas test. The modified Thomas test is frequently used by clinicians to assess hip extension flexibility. Studies examining the reliability of measures of the modified Thomas test are limited. This study included 42 healthy subjects. The modified Thomas test was performed on each subject to quantify hip extension flexibility by using an inclinometer and a goniometer. High interrater reliability was determined for each instrument (r = 0.91-0.93; ICC = 0.89-0.92). High intrarater parallel-forms reliability was found for each examiner between the instruments (r = 0.089-0.92; ICC = 0.91-0.93). High interrater parallel-forms reliability also was found between instruments (r = 0.86-0.93; ICC = 0.86-0.92). The high correlations obtained in this study suggest that the inclinometer and the goniometer are reliable instruments for measuring hip extension flexibility. The results also indicate that the two instruments can be used interchangeably for measuring hip extension flexibility.

Open repair of aortic aneurysms involving the renal vessels.

This retrospective review examines the open surgical repair of intact juxtarenal (JRAAs) and suprarenal (SRAAs) aortic aneurysms to estimate effects on survival and renal function. Patients undergoing open repair of JRAA and SRAA were identified. Preoperative medical comorbidities and perioperative and late outcomes were recorded. Primary end points were survival (perioperative and long-term survival) and changes in renal function (acute tubular necrosis [ATN], acute dialysis, and late functional decline). Associations between outcomes and clinical variables were examined using univariate and multivariate techniques. Between December 1996 and September 2006, 678 patients underwent open repair of aortic aneurysms, including 150 aneurysms involving the renal vessels (134 JRAAs, 16 SRAAs). Perioperative mortality was 3% and long-term survival was 69% at 5 years. Fourteen percent of patients experienced ATN, and 7% required acute in-hospital dialysis. Late renal function remained unchanged or improved in 75%. These results demonstrate a perioperative mortality and renal complication rate in keeping with previous reports of open abdominal aortic aneurysm repairs involving the renal vessels. Future implementation of branch and fenestrated aortic endografts to treat similar aneurysms should approximate these results prior to widespread acceptance.

Electrical stimulation using implantable radiofrequency microstimulators to relieve pain associated with shoulder subluxation in chronic hemiplegic stroke.

Objective. To evaluate the ability to relieve shoulder pain by implanting ceramic-case versions of radiofrequency microstimulators (RFM) in paralyzed shoulder muscles. Materials and Methods. A 66-year-old man, who had left-sided chronic hemiplegia due to a stroke five years previously, had developed shoulder subluxation resulting in pain. Two RFM devices were implanted, one next to the axillary nerve and one at the motor point of the middle deltoid muscle. Electrical stimulation at both sites was commenced two weeks after implantation for a six-month period. Our evaluation of the effectiveness of the RFM devices has been by measuring pain (using the visual analog scale: VAS), range of motion at the shoulder, strength of the deltoid muscle, degree of shoulder subluxation, and muscle atrophy. Following commencement of stimulation, follow-up evaluations were performed at one, two, three, four, and six weeks, three and six months, and after six months of no stimulation. Results. During the treatment period of six months of stimulation, the patient's pain had reduced from 70 to 0 on the VAS. At six months after completion of the treatment, pain relief and effective evoked muscle contraction have remained. Conclusion. Although these results suggest that the feasibility of using RFM devices implanted both epineurally to the axillary nerve and next to the muscle motor point in this one patient, to relieve pain and elicit contraction, further investigation is needed to demonstrate the clinical feasibility of using RFMs for treating poststroke shoulder pain.

Double-blind, randomized controlled pilot study of bilateral cerebellar stimulation for treatment of intractable motor seizures.

PURPOSE: The efficacy and safety of cerebellar stimulation (CS) was reevaluated in a double-blind, randomized controlled pilot study on five patients with medically refractory motor seizures, and especially generalized tonic-clonic seizures. METHODS: Bilateral modified four-contact plate electrodes were placed on the cerebellar superomedial surface through two suboccipital burr holes. The implanted programmable, battery-operated stimulator was adjusted to 2.0 microC/cm(2)/phase with the stimulator case as the anode; at this level, no patient experienced the stimulation. Patients served as their own controls, comparing their seizure frequency in preimplant basal phase (BL) of 3 months with the postimplant phases from 10 months to 4 years (average, eight epochs of 3 months each). During the month after implantation, the stimulators were not activated. The patient and the evaluator were blinded as to the next 3-month epoch, as to whether stimulation was used. The patients were randomized into two groups: three with the stimulator ON and two with the stimulator OFF. After a 4-month postimplantation period, all patients had their stimulator ON until the end of the study and beyond. Medication was maintained unchanged throughout the study. EEG paroxysmal discharges also were measured. RESULTS: Generalized tonic-clonic seizures: in the initial 3-month double-blind phase, two patients were monitored with the stimulation OFF; no change was found in the mean seizure rate (patient 1, 100%, and patient 5, 85%; mean, 93%), whereas the three patients with the stimulation initially ON had a reduction of seizures to 33% (patient 2, 21%; patient 3, 46%; patient 4, 32%) with a statistically significant difference between OFF and ON phase of p = 0.023. All five patients then were stimulated and monitored. At the end of the next 6 months of stimulation, the five patients had a mean seizure rate of 41% (14-75%) of the BL. The second patient developed an infection in the implanted system, which had to be removed after 11 months of stimulation; the seizures were being reduced with stimulation to a mean of one per month from a mean of 4.7 per month (BL level) before stimulation. At the end of 24 months, three patients were monitored with stimulation, resulting in a further reduction of seizures to 24% (11-38%). Tonic seizures: four patients had these seizures, which at 24 months were reduced to 43% (10-76%). Follow-up surgery was necessary in four patients because of infection in one patient and lead/electrode displacement needing repositioning in three patients. The statistical analysis showed a significant reduction in tonic-clonic seizures (p < 0.001) and tonic seizures (p < 0.05). CONCLUSIONS: The superomedial cerebellar cortex appears to be a significantly effective and safe target for electrical stimulation for decreasing motor seizures over the long term. The effect shows generalized tonic-clonic seizure reduction after 1-2 months and continues to decrease over the first 6 months and then maintains this effectiveness over the study period of 2 years and beyond.