Elevated Neutrophil to Lymphocyte Ratio is Associated with Worse Outcomes after Carotid Endarterectomy in Asymptomatic Patients.

OBJECTIVE: Management of carotid artery stenosis (CAS) remains controversial and proper patient selection critical. Elevated neutrophil to lymphocyte ratio (NLR) has been associated with poor outcomes after vascular procedures. The effect of NLR on outcomes after carotid endarterectomy (CEA) in asymptomatic and symptomatic patients is assessed. MATERIALS AND METHODS: A retrospective review was conducted of all patients between 2010 and 2018 with carotid stenosis >70% as defined by CREST 2 criteria. A total of 922 patients were identified, of whom 806 were treated with CEA and 116 non-operatively with best medical therapy (BMT). Of patients undergoing CEA, 401 patients (290 asymptomatic [aCEA], 111 symptomatic [sCEA]) also had an available NLR calculated from a complete blood count with differential. All patients treated with BMT were asymptomatic and had a baseline NLR available. Kaplan-Meier analysis assessed composite ipsilateral stroke or death over 3 years. RESULTS: In sCEA group, the 3-year composite stroke/death rates did not differ between NLR < 3.0 (22.9%) vs NLR > 3.0 (38.1%) (P=.10). In aCEA group, patients with a baseline NLR >3.0 had an increased risk of 3-year stroke/death (42.6%) compared to both those with NLR <3.0 (9.3%, P<.0001) and those treated with BMT (23.6%, P=.003). In patients with NLR <3.0, aCEA showed a superior benefit over BMT with regard to stroke or death (9.3% vs. 26.2%, P=.02). However, in patients with NLR >3.0, there was no longer a benefit to prophylactic CEA compared to BMT (42.6% vs. 22.2%, P=.05). Multivariable analysis identified NLR >3.0 (HR, 3.23; 95% CI, 1.93-5.42; P<.001) and congestive heart failure (HR, 2.18; 95% CI, 1.33-3.58; P=.002) as independent risk factors for stroke/death in patients with asymptomatic carotid artery stenosis. CONCLUSIONS: NLR >3.0 is associated with an increased risk of late stroke/death after prophylactic CEA for asymptomatic carotid artery stenosis, with benefits not superior to BMT. NLR may be used to help with selecting asymptomatic patients for CEA. The effect of NLR and outcomes in symptomatic patients requires further study. Better understanding of the mechanism(s) for NLR elevation and medical intervention strategies are needed to modulate outcome risk in these patients.

Paclitaxel-coated peripheral arterial devices are associated with improved overall survival and limb salvage in patients with chronic limb-threatening ischemia.

OBJECTIVE: Paclitaxel (PTX)-coated peripheral arterial devices have been shown to decrease femoropopliteal artery restenosis and the need for reintervention compared with non-PTX-coated devices. The data regarding PTX efficacy and safety come from randomized controlled trials that almost exclusively enrolled patients with claudication. The outcomes of PTX treatment in patients who present with chronic limb-threatening ischemia (CLTI) are unknown. This study compares long-term outcomes in patients with CLTI treated with and without PTX. METHODS: We retrospectively reviewed 983 patients with CLTI treated with femoropopliteal artery angioplasty, atherectomy, stent, or combination between 2011 and 2019. Procedures were performed with additional proximal or distal tibial interventions as needed. Kaplan-Meier survival analysis and multivariable Cox-regression analysis compared overall survival (OS), amputation-free survival (AFS), freedom from major amputation (ff-MA), and freedom from target vessel revascularization (ff-TVR) between patients treated with and without PTX. RESULTS: Demographics, comorbidities, and Rutherford class were similar between 574 PTX (58.5%) and 409 non-PTX (41.6%) patients except that non-PTX patients were more likely to be male (56.2% vs 49.7%), dialysis dependent (19.6% vs 14.3%), and have higher average creatinine (2.3 vs 1.8 mg/dL). Through 4-year follow-up, the PTX group demonstrated a significant increase in OS (56.2% vs 43.9%, P = .013), AFS (52.6% vs 36.1%, P < .0001), ff-MA (87.4% vs 78.7%, P = .0007), and ff-TVR (77.6% vs 70.6%, P = .012). Multivariable Cox-regression analysis demonstrated that PTX treatment was associated with improved OS, AFS, ff-MA, and ff-TVR. CONCLUSIONS: In patients with CLTI, treatment with a PTX-coated device is associated with improved OS, AFS, ff-MA, and ff-TVR through 4-year follow-up. PTX-coated devices may be especially beneficial in patients who present with CLTI.

Elevated neutrophil to lymphocyte ratio is associated with decreased amputation-free survival after femoropopliteal percutaneous revascularization.

BACKGROUND: An elevated neutrophil-lymphocyte ratio (NLR) is a biomarker associated with adverse outcomes after cardiovascular surgery. This study evaluates the association of preoperative NLR with clinical outcomes after peripheral vascular intervention (PVI) of the femoropopliteal segments. METHODS: A retrospective review identified 488 patients who underwent percutaneous interventions of femoropopliteal arteries between 2011 and 2018 and had a pre-procedural complete blood count with differential with normal white blood cell count within 30 days prior to intervention. Amputation-free survival (AFS), survival, and freedom from major amputation were assessed using Kaplan-Meier methods. Cohorts of patients with NLR <3 (Low), 3-4 (Mid), and >4 (High) were compared using univariate and multivariable statistical models. In these analyses NLR was analyzed as a continuous variable to correlate with clinical outcomes. RESULTS: Mean age was 71.7±12.8 years and males constituted 55.5%. The majority of patients presented with chronic limb threatening ischemia (CLTI, 78.5%). Increasing NLR was correlated with increasing rates of comorbidities, except for smoking history. The 30-day mortality rates increased with increasing NLR: 1.4%, 4.3%, and 7.0% for low (<3), mid (3-4) and high (>4) NLR groups, respectively (P=0.005). Patients with a lower pre-operative NLR achieved significantly greater amputation-free survival at 4-year follow-up: low NLR, 65.5%; mid NLR, 37.5%; and high NLR, 17.6% (P<0.0001). By multivariable analysis, increasing NLR, advanced age, CLTI, and dialysis-dependent renal failure reduced AFS. CONCLUSIONS: Elevated NLR is an independent predictor of decreased AFS following percutaneous interventions of femoropopliteal segments. Further research on identification and modulation of risk factors for high NLR are warranted.

Systematic review of hemostatic agents used in vascular surgery.

BACKGROUND: Hemostatic agents are routinely used in vascular surgery to complement proper suture techniques and decrease the risk of perioperative bleeding. A relative lack of comparative research studies have left surgeons with the option of choosing hemostatic agents based on their personal experience. The present review has highlighted the efficacy and safety of hemostatic agents and categorized them according to their primary mechanism of action and cost. METHODS: A systematic search strategy encompassing hemostatic agent products was deployed in the PubMed database. Single-center and multicenter, randomized, controlled trials with >10 patients were included in the present study. RESULTS: We reviewed 12 studies on the efficacy and safety of hemostatic agents compared with manual compression or other hemostatic agents. Using the time to hemostasis as the primary end point, all studies had found hemostatic agents to be significantly more efficient than manual compression. Likewise, adhesives (high pressure sealants) and dual agents (containing biologically active and absorbable components) were found to be more efficient, but costlier, than agents with either biologically active or absorbable components only. Agents with porcine or bovine constituents were found to trigger anaphylactic reactions in rare cases. Additionally, the absence of fibrin stabilizing factor XIII in a brand of fibrin sealant was speculated to reduce the affinity of the fibrin sealant for the expanded polytetrafluoroethylene graft. The cost of agents varied greatly depending on their active ingredient. CONCLUSIONS: Hemostatic agents appear to be highly effective at decreasing the risk of bleeding during surgical procedures. Although some hemostatic agents were demonstrated to achieve hemostasis faster than others, most are able to control bleeding within <10 minutes. Based on the limited data, the least expensive agents might suffice for limited suture lines used in routine procedures.

Paclitaxel-Coated Peripheral Arterial Devices are Associated with Reduced Mortality in Younger Patients.

BACKGROUND: Paclitaxel-coated devices have been shown to decrease restenosis when used in the femoropopliteal artery. Recent reports have suggested a possible risk of increased late mortality in patients treated with paclitaxel. It has been suggested that younger patients and those with limited comorbidities may be at higher risk. Our objective was to analyze long-term mortality based on patient age comparing treatment with paclitaxel to uncoated devices. METHODS: We performed a retrospective review of 1,170 consecutive patients who underwent femoropopliteal percutaneous intervention by angioplasty, atherectomy, stent placement, or combination between 2011 and 2018. Patients were grouped by age at the time of procedure: <60 years old (n = 244, 20.9%), 60-80 years old (n = 635, 54.3%), and >80 years old (n = 291, 24.9%). Within each group, patients were further divided by use of paclitaxel. The primary outcome measure was survival assessed by Kaplan-Meier analysis. Differences between the groups were analyzed with analysis of variance. Multivariable analysis was performed using Cox proportional hazard models. RESULTS: Of the 1,170 patients who underwent femoropopliteal percutaneous intervention, 654 (55.9%) received a paclitaxel-coated device during treatment and 516 (44.1%) did not. Mean age of the overall patient cohort was 70.4 ± 12.6 years and 663 (56.7%) were male. When comparing the groups by age we found an increase in age but a decrease in the proportion of patients who smoke. The use of paclitaxel-coated devices was similar across the groups (<60 years old, 56.2%; 60-80 years old, 57.0%; >80 years old, 52.6%; P = 0.45). Demographics and comorbidities were similar between the patients treated with and without paclitaxel within each age group except more males in the <60-year-old group treated without paclitaxel and more patients with chronic limb threatening ischemia in the >80-year-old group treated with paclitaxel. In patients <60 and 60-80 years old paclitaxel use was associated with increased survival at 4 years: <60 (80.7% vs. 64.4%; P = 0.04); 60-80 (63.2% vs. 55.1%; P = 0.04). Survival was similar in the >80-year-old group (46.6% vs. 32.8%; P = 0.65). CONCLUSIONS: Our data suggest that the use of paclitaxel-coated arterial devices is not associated with increased mortality. On the contrary, our data show that younger patients treated with paclitaxel show improved survival compared with those treated without paclitaxel. Paclitaxel-coated devices may be used with continued caution especially in patients at high risk for restenosis.

Heparin-bonded versus standard polytetrafluoroethylene arteriovenous grafts: A Bayesian perspective on a randomized controlled trial for comparative effectiveness.

BACKGROUND: Heparin-bonded polytetrafluoroethylene grafts were marketed to improve hemodialysis access outcomes but are twice the cost of standard polytetrafluoroethylene. We launched a randomized trial of heparin-bonded polytetrafluoroethylene versus standard polytetrafluoroethylene for hemodialysis access to compare patency. Since the trial began, additional studies were published with heterogeneous findings. We performed an interim analysis by Bayesian methods using prior probability from meta-analysis of existing literature. METHODS: NCT01601873 is a randomized, blinded trial of heparin-bonded polytetrafluoroethylene versus standard polytetrafluoroethylene for dialysis access at 5 sites. Planned sample size was 200 with 1-year primary patency as the primary endpoint. At interim analysis (50% of sample size at 1 year), we also performed a meta-analysis for 1-year primary patency with a random effects model to compute summary rate ratio and standard-error estimates. Meta-analysis estimates formed a prior probability for a Bayesian Cox regression model, and trial data were reanalyzed to develop posterior probability of heparin-bonded polytetrafluoroethylene effectiveness at our hypothesized effect size. Futility analysis was conducted using posterior probability estimates. RESULTS: One hundred and five patients were enrolled at the time of interim analysis. One-year primary patency was 34.9% in the heparin-bonded-polytetrafluoroethylene group vs 32.7% in the standard-polytetrafluoroethylene group (P = .884). Summary rate ratio from the meta-analysis (1,209 patients) was 0.87 favoring heparin-bonded polytetrafluoroethylene (P = .33). Posterior hazard ratio from Cox regression was 0.90 (credible interval 0.70-1.13) favoring heparin-bonded polytetrafluoroethylene, which was not significant. Bayesian posterior probability of the a priori hypothesized 20% better patency with heparin-bonded polytetrafluoroethylene was 24%. Sample size to detect superiority with the small observed effect size would require about 3,800 subjects. CONCLUSION: Current evidence does not demonstrate sufficiently large benefit of heparin-bonded polytetrafluoroethylene over standard polytetrafluoroethylene for dialysis access to justify higher cost. Given similar 1-year patency rates, a conclusive finding of superiority was judged to be infeasible, and the trial was stopped for futility.

Anatomic criteria in the selection of treatment modality for atherosclerotic carotid artery disease.

OBJECTIVE: Three procedures are currently available to treat atherosclerotic carotid artery stenosis: carotid endarterectomy (CEA), transfemoral carotid artery stenting (TF-CAS), and transcarotid artery revascularization (TCAR). Although there is considerable debate evaluating each of these in a head-to-head comparison to determine superiority, little has been mentioned concerning the specific anatomic criteria that make one more appropriate. We conducted a study to define anatomic criteria in relation to inclusion and exclusion criteria and relative contraindications. METHODS: A retrospective review was conducted of 448 carotid arteries from 224 consecutive patients who underwent a neck and head computed tomography arteriography (CTA) scan before carotid intervention for significant carotid artery stenosis. Occlusion of the internal carotid artery (ICA) occurred in 15, yielding 433 arteries for analysis. Anatomic data were collected from CTA images and demographic and comorbidities from chart review. Eligibility for CEA, TF-CAS, and TCAR was defined on the basis of anatomy, not by comorbidity. RESULTS: CTA analysis revealed that 92 of 433 arteries (21%) were ineligible for CEA because of carotid lesions extending cephalad to the second cervical vertebra. Overall, 26 arteries (6.0%) were not eligible for any type of carotid artery stent because of small ICA diameter (n = 11), heavy circumferential calcium (n = 14), or combination (n = 1). An additional 126 arteries were ineligible for TF-CAS on the basis of a hostile aortic arch (n = 115) or severe distal ICA tortuosity (n = 11), yielding 281 arteries (64.9%) that were eligible. In addition to the 26 arteries ineligible for any carotid stent, TCAR was contraindicated in 39 because of a clavicle to bifurcation distance <5 cm (n = 17), common carotid artery diameter <6 mm (n = 3), or significant plaque at the TCAR sheath access site (n = 20), yielding 368 arteries (85.0%) that were eligible for TCAR. CONCLUSIONS: A significant proportion of patients who present with carotid artery stenosis have anatomy that makes one or more carotid interventions contraindicated or less desirable. Anatomic factors should play a key role in selecting the most appropriate procedure to treat carotid artery stenosis. Determination of superiority for one procedure over another should be tempered until anatomic criteria have been assessed to select the best procedural options for each patient.

Elevated neutrophil-lymphocyte ratio predicts mortality following elective endovascular aneurysm repair.

OBJECTIVE: The neutrophil-lymphocyte ratio (NLR) is an inexpensive and useful inflammatory marker that incorporates the balance of the innate (neutrophil) and adaptive (lymphocyte) immune responses. Data exist on the association between NLR and mortality in various coronary diseases and in cancer surgery, but there is a paucity of data on the impact of preoperative NLR on vascular surgical outcomes. The aim of this study was to evaluate the relationship between preoperative NLR and elective endovascular aortic aneurysm repair (EVAR) outcome. METHODS: A retrospective review of all patients who underwent elective EVAR at a single institution between 2010 and 2018 was conducted (n = 373). Only patients who had a preoperative complete blood count with differential within 30 days of their operation were included. The NLR was computed by dividing the absolute neutrophil count by the absolute lymphocyte count. A receiver operating characteristic curve was used to determine the optimal cutoff value of NLR with the strongest association with mortality. NLR was dichotomized so that patients with NLR above the threshold were at increased risk of mortality compared with those below it. Continuous variables were analyzed using Wilcoxon nonparametric signed-rank test and categorical variables with the Fisher exact test. A comparison of NLR and mortality was completed using Kaplan-Meier survival analysis. Cox regression analysis was used to evaluate factors associated with mortality through 5-year follow-up. RESULTS: Overall, 108 patients were included in this study. An NLR ≥ 4.0 was found to be associated with mortality (P < .0001). Thirty-two patients composed the High-NLR (NLR ≥ 4.0) group and the remaining 76 patients formed the Low-NLR (NLR < 4.0) group. Baseline characteristics were similar between groups, except that the High-NLR group was older (77.9 vs 74.4; P = .047). At a mean of 36.4 months follow-up, the overall mortality rate was 32.4%. Although there were no differences in the perioperative period, the Kaplan-Meier estimates of mortality were significantly greater in the High-NLR group at 1, 2, and 5 years postoperatively (P < .0001). The mean preoperative NLR of the deceased was higher (5.94 ± 5.20; median, 4.75; interquartile range, 3.17-7.83) than those who survived (2.87 ± 1.61; median, 2.53; interquartile range, 1.97-3.49) (P < .0001). Secondary interventions and sac enlargement rates were similar between groups. On univariable analysis, NLR (hazard ratio [HR], 1.17; 95% confidence interval [CI], 1.10-1.23; P < .0001), age (HR, 1.06; 95% CI, 1.02-1.11; P = .004), and aneurysm diameter (HR, 1.04; 95% CI, 1.01-1.07; P = .003) were associated with mortality. On multivariable analysis, NLR (HR, 1.19; 95% CI, 1.12-1.27; P < .0001), age (HR, 1.06; 95% CI, 1.01-1.11; P = .026), and aneurysm diameter (HR, 1.04; 95% CI, 1.02-1.07; P = .003) were associated with mortality. CONCLUSIONS: Patients with an elevated preoperative NLR, irrespective of other comorbidities, may represent a previously unrecognized subset of patients who are at heightened risk of mortality after elective EVAR. A complete blood count with differential is an inexpensive test that may be used as a prognostic indicator for outcome after EVAR. Further research is warranted to identify clinical, pathological, or anatomical factors associated with an elevated NLR and to determine modifiable factors, which may help improve long-term survival.

Frequency of perigraft hygroma after open aortic reconstruction.

OBJECTIVE: The incidence of perigraft hygroma (PGH) development after aortic reconstruction remains poorly defined and its clinical relevance is questionable. This study was designed to establish the incidence of and determine the risk factors associated with PGH formation and its outcomes. METHODS: Patients who underwent open aortic reconstruction for either aneurysmal or occlusive disease with an expanded polytetrafluoroethylene (ePTFE) or polyester graft from 2004 to 2018 were retrospectively reviewed (n = 262). Only those who had follow-up imaging 3 or more months after repair were included. Patients with mixed graft types were excluded. PGH was defined as a perigraft fluid collection of 30 mm or greater in diameter with a radiodensity of 30 or fewer Hounsfield units on computed tomography at a minimum of 3 postoperative months. Analysis was conducted between patients with and without PGH. RESULTS: One hundred forty patients met the inclusion criteria: 88 were treated with ePTFE and 52 with polyester grafts. Twenty-three patients (16.4%) were found to have radiologic evidence of PGH. PGH developed more frequently in patients with ePTFE (21/88 [23.9%]) compared with those with polyester grafts (2/52 [3.8%]) (P = .002). Mean PGH size was 63.5 ± 36.4 mm (range, 33-153 mm) and the average time to PGH detection 27.7 months (range, 3-112 months). Baseline characteristics were similar between the groups. Patients who developed PGH had larger aneurysms, more often received ePTFE grafts, had larger graft diameters, and had bifurcated grafts. The overall mortality was 32.1% at a mean follow-up of 5.2 years. The 5-year mortality rates were similar between patients with and without PGH (26.1% vs 18.8%; P = .41). Of the 23 patients with PGH, 4 (all with ePTFE) presented with symptoms related to the PGH. The average size of symptomatic and asymptomatic PGH were 11.5 and 4.8 cm, respectively. Mortality rates overall were similar between those with and without symptoms (50.0% vs 36.8%; P = .99). CONCLUSIONS: Nearly one-quarter of aortic reconstructions with ePTFE are associated with PGH formation compared with 4% with polyester. Clinically significant PGH-related symptom development occurs in 20%. Patient education and close surveillance are warranted. Manufacturer's device modification is needed.

Paclitaxel-coated peripheral artery devices are not associated with increased mortality.

OBJECTIVE: Long-term safety concerns have been raised that the use of paclitaxel-coated balloons and stents is linked to excess mortality. Our objective was to compare outcomes in patients treated with paclitaxel vs uncoated devices and to analyze long-term mortality. METHODS: We conducted a retrospective single-institution review of 1170 consecutive patients who underwent femoropopliteal percutaneous revascularization by angioplasty, atherectomy, stent placement, or combination between 2011 and 2018. The primary outcome measure was all-cause mortality. Groups were divided into patients who received paclitaxel (n = 652) and those who did not (n = 518). Categorical variables were assessed using χ2 analysis and continuous variables with the Wilcoxon signed rank test. A multivariable analysis was performed using multivariable logistic regression models. Mortality was compared using Kaplan-Meier survival analysis. RESULTS: Demographics, risk factors, and Rutherford class were similar between the groups, except that the paclitaxel group was more likely to have diabetes (60.9% vs 55.0%; P = .04), was less likely to be on dialysis (10.7% vs 14.9%; P = .04), and had lower average creatinine concentration (1.6 ± 1.8 mg/dL vs 2.0 ± 2.3 mg/dL; P = .003). There were no differences in all-cause mortality through 2 years between paclitaxel and no-paclitaxel cohorts (25.5% vs 30.3%; log-rank, P = .098). At 3 years and 3.5 years, mortality was significantly lower in the paclitaxel group: year 3, 32.1% vs 39.4% (log-rank, P = .041); year 3.5, 35.2% vs 43.9% (log-rank, P = .027). Survival rates were not significantly different in examining subgroups by diabetes, chronic kidney disease, presence of chronic limb-threatening ischemia, or paclitaxel-coated balloon manufacturer. Multivariable analysis demonstrated that age, dialysis, chronic limb-threatening ischemia, chronic kidney disease, and congestive heart failure were independent risk factors for mortality, whereas paclitaxel use was associated with lower mortality. CONCLUSIONS: The use of paclitaxel-coated balloons and stents does not increase mortality compared with uncoated devices out to 3.5 years. Paclitaxel-coated devices can be used with continued caution, especially in patients at increased risk of restenosis. Further long-term studies are needed to determine the risk of late mortality.

Comparison of patient-specific factors and outcomes for one- and two-stage basilic vein transposition fistulas.

OBJECTIVE: The decision to perform a one- or two-stage basilic vein transposition (BVT) arteriovenous fistula often depends on factors such as the vessel's diameter, the patient's disposition, and the surgeon's preference. This study's aim was to analyze patency by BVT staging technique and to identify patient-specific characteristics associated with outcomes. METHODS: A retrospective review of all patients who underwent one- or two-stage BVT at our institution between 2008 and 2013 was performed. Comparisons of age, sex, race, and associated comorbidities were made. Clinical course was followed for 2 years after fistula construction, comparing maturation rate, thrombosis, stenosis, steal, and catheter infections. Continuous variables were expressed as means or medians and compared across stage and maturation groups by t-test; differences between categorical variables were assessed using Fisher exact test. A Kaplan-Meier survival analysis was performed to calculate patency rates and compared by log-rank test. RESULTS: There were 49 one-stage and 169 two-stage BVTs examined. The mean age of the patients at time of construction was 58 years and 61 years for one-stage and two-stage patients, respectively. There was no difference in mean proximal, mid, or distal basilic vein diameters between the groups. Fistula maturation was similar between stage groups, with primary failure affecting 26.5% of one-stage and 24.3% of two-stage BVTs (P = .78). Across one- and two-stage BVTs, 2-year primary patency rates were 51% and 52%, respectively (P = .68); primary assisted patency, 66% and 85% (P = .05); and secondary patency, 64% and 78% (P = .26). Multivariate logistic regression showed a trend toward diabetics at higher risk for primary failure (odds ratio, 1.60; 95% confidence interval, 0.95-2.55; P = .07). For two-stage BVT, the median interstage period between operations lasted 105.00 (interquartile range, 77.00-174.50) days and was associated with a large proportion of the overall primary failures (19/41 [46%]) and catheter-related infections (12/20 [60%]). CONCLUSIONS: This study demonstrates similar maturation, primary patency, primary assisted patency, secondary patency, and complication rates in a large series of BVTs constructed using a one- or two-stage transposition technique regardless of vein diameter. Diabetes was associated with primary failure by either technique. High proportions of overall primary failures and catheter-related infections observed in two-stage BVT occurred during the interstage, suggesting that a one-stage technique should be considered over a two-stage approach to minimize the risk of catheter infection and to decrease time to maturity.

Elevated Peak Systolic Velocity and Velocity Ratio from Duplex Ultrasound are Associated with Hemodynamically Significant Lesions in Arteriovenous Access.

BACKGROUND: Duplex ultrasound (DUS) is reliably used to detect lesions in the peripheral and carotid arterial beds and venous system. Although commonly used in clinical practice, duplex criteria to define lesions in arteriovenous access are not well characterized. This study will define the optimal Doppler-derived peak systolic velocity (PSV) and velocity ratio (VR) to identify >50% lesions in arteriovenous fistulas (AVF) and arteriovenous grafts (AVG). METHODS: This retrospective analysis includes patients with both DUS and fistulogram within 30 days. DUS-derived PSV and VR were recorded for 3 segments of each access and compared with fistulograms of the same 3 segments of each AV access. Receiver operating characteristic (ROC) was used to determine the optimal DUS criteria for diagnosis of >50% stenosis. RESULTS: Fifty pairs of imaging in 40 patients were available for analysis. Mean PSV and VR for segments with greater than 50% stenosis were significantly greater than those without; mean PSV of 480 cm/sec vs. 297 cm/sec (P < 0.001) and mean VR of 3.81 vs. 2.09 (P < 0.001). The ROC analysis demonstrated an optimal PSV of 404 and VR of 2.2 to diagnose >50% stenosis with area under the curve of 0.825 and 0.821 for PSV and VR, respectively. PSV of 500 had sensitivity (Se) of 0.60, specificity (Sp) of 0.86, positive predictive value (PPV) of 0.72, and negative predictive value (NPV) of 0.78. VR of 3.0 had Se of 0.52, Sp of 0.91, PPV of 0.77, and NPV of 0.75. CONCLUSIONS: DUS-derived PSV of 400 cm/sec and VR of 2.25 have good discrimination to predict greater than 50% stenosis in AVFs and AVGs. Given the broad range of velocities in AV accesses, a threshold of PSV greater than 500 cm/sec and VR greater than 3.0, will reliably identify graft-threatening lesions. Se and Sp of PSV 500 are 0.596 and 0.854, respectively. Se and Sp for VR 3.0 are 0.519 and 0.894, respectively.

Upper Extremity Steal Syndrome Is Associated with Atherosclerotic Burden and Access Configuration.

BACKGROUND: Clinically significant steal syndrome occurs in a subset of dialysis patients with arteriovenous (AV) access. Factors associated with steal are poorly understood. Severe symptoms require access revision or sacrifice, potentially jeopardizing access options. Our objective was to review our dialysis access experience to identify factors associated with significant steal syndrome. METHODS: We reviewed all adult patients undergoing their first permanent upper extremity access, AV fistula (AVF) or AV graft (AVG), between January 2008 and July 2011 at a single center. Medical, demographic, and access characteristics were collected from our electronic medical record and a local dialysis center's database. Patients who required correction of steal syndrome were compared with the larger access cohort. Statistical analysis included Fisher's exact test and χ(2) for noncontinuous variables and unpaired t-test for continuous variables. RESULTS: Of the 303 patients, 15 required correction for steal syndrome (8 of 232 AVF and 7 of 71 AVG). Eight were ligated; 2 were initially banded, then ligated; and 5 underwent distal revascularization with interval ligation. Coronary artery disease was more prevalent in steal syndrome patients (66.7% vs. 25%, P = 0.001); the same was found with peripheral arterial disease (40% vs. 13.8%, P = 0.02). Furthermore, more patients with steal syndrome were on clopidogrel for cardiovascular reasons (40% vs. 9%, P = 0.002). Steal syndrome only developed with AVF and AVG using brachial artery inflow. No cases of steal syndrome arose from radial/ulnar inflow (P = 0.03). All AVG with steal syndrome had a straight configuration; no looped AVG developed steal (P = 0.02). Other patient characteristics such as age, sex, race, hypertension, diabetes mellitus, congestive heart failure, cerebrovascular accident, cause of end-stage renal disease, and other medication history were not different between groups. CONCLUSIONS: Clinically significant steal syndrome is associated with disease in coronary and peripheral arterial beds. In addition, the use of brachial artery inflow and straight AVG configuration is associated with steal syndrome. Consideration should be given to construction of access using smaller forearm arteries and looped AVG configuration in patients with high risk for steal. In addition, such patients may require more vigilant monitoring for development of steal after access construction.

Comparative occupational radiation exposure between fixed and mobile imaging systems.

OBJECTIVE: Endovascular intervention exposes surgical staff to scattered radiation, which varies according to procedure and imaging equipment. The purpose of this study was to determine differences in occupational exposure between procedures performed with fixed imaging (FI) in an endovascular suite compared with conventional mobile imaging (MI) in a standard operating room. METHODS: A series of 116 endovascular cases were performed over a 4-month interval in a dedicated endovascular suite with FI and conventional operating room with MI. All cases were performed at a single institution and radiation dose was recorded using real-time dosimetry badges from Unfors RaySafe (Hopkinton, Mass). A dosimeter was mounted in each room to establish a radiation baseline. Staff dose was recorded using individual badges worn on the torso lead. Total mean air kerma (Kar; mGy, patient dose) and mean case dose (mSv, scattered radiation) were compared between rooms and across all staff positions for cases of varying complexity. Statistical analyses for all continuous variables were performed using t test and analysis of variance where appropriate. RESULTS: A total of 43 cases with MI and 73 cases with FI were performed by four vascular surgeons. Total mean Kar, and case dose were significantly higher with FI compared with MI. (mean ± standard error of the mean, 523 ± 49 mGy vs 98 ± 19 mGy; P < .00001; 0.77 ± 0.03 mSv vs 0.16 ± 0.08 mSv, P < .00001). Exposure for the primary surgeon and assistant was significantly higher with FI compared with MI. Mean exposure for all cases using either imaging modality, was significantly higher for the primary surgeon and assistant than for support staff (ie, nurse, radiology technologist) beyond 6 feet from the X-ray source, indicated according to one-way analysis of variance (MI: P < .00001; FI: P < .00001). Support staff exposure was negligible and did not differ between FI and MI. Room dose stratified according to case complexity (Kar) showed statistically significantly higher scattered radiation in FI vs MI across all quartiles. CONCLUSIONS: The scattered radiation is several-fold higher with FI than MI across all levels of case complexity. Radiation exposure decreases with distance from the radiation source, and is negligible outside of a 6-foot radius. Modern endovascular suites allow high-fidelity imaging, yet additional strategies to minimize exposure and occupational risk are needed.

The end stage of dialysis access: femoral graft or HeRO vascular access device.

BACKGROUND: Maintaining and establishing vascular access in end-stage renal disease (ESRD) patients is complicated when they are poor candidates for traditional upper extremity access. Our objective was to compare our experience with 2 alternative dialysis accesses, the femoral arteriovenous graft (fAVG) and the Hemodialysis Reliable Outflow (HeRO), in patients with limited remaining options. METHODS: A single institution, retrospective review of ESRD patients with fAVG or HeRO placed between May 2009 and February 2013 was performed. Adult patients were selected by reviewing all arteriovenous grafts placed at a single institution. Patient demographics, medical history, access characteristics, and outcomes were recorded from both institutional and dialysis center databases. Data were evaluated using Fisher's exact test, unpaired t-test for continuous variables, log-rank test, and univariate analysis. RESULTS: A total of 56 accesses in 43 unique patients met these criteria: 35 fAVG and 21 HeRO; with 1 HeRO patient lost immediately to follow-up. Clinical variables were similar except the HeRO group had more diabetic patients (60% HeRO, 22.9% fAVG; P = 0.01). The average number of years on hemodialysis was 7.0 ± 1.0 for fAVG and 5.7 ± 0.9 for HeRO (P = 0.41). Primary patency was 40.5%, 18.7%, and 14.9% for fAVG and 29.0%, 29.0%, and 0% for HeRO at 6 months, 12 months, and 2 years (P = 0.67), respectively. Assisted primary patency was also similar, with 43.8%, 29.4%, and 13.8% for fAVG and 34.8%, 34.8%, and 17.4% for HeRO at 6 months, 12 months, and 2 years (P = 0.81), respectively. Secondary patency was 62.6%, 50.6%, 19.3% for fAVG and 68.0%, 53.5%, 38.3% for HeRO at 6 months, 12 months, and 2 years (P = 0.69), respectively. Average number of interventions to maintain patency for fAVG was 1.1 ± 1.47 and 1.65 ± 2.52 for HeRO (P = 0.35). Infectious complications occurred in 29% of fAVG and 15% of HeRO (P = 0.33). CONCLUSIONS: Patients who received either fAVG or HeRO experience poor access patency. ESRD patients who receive either of these procedures appear to be at the end stage of available access options.

Arteriovenous grafts have higher secondary patency in the short term compared with autologous fistulae.

BACKGROUND: To estimate patency of arteriovenous fistulas (AVFs) and grafts (AVGs) for dialysis access. METHODS: Records of all adult patients who had a dialysis access placed from January 2008 to June 2011 were retrospectively reviewed. RESULTS: A total of 494 patients with 655 accesses (390 AVFs, 265 AVGs) were examined. We found that AVG fared worse in assisted primary patency. But AVG had superior secondary patency up to 1.2 years (hazard ratio [HR] .6, confidence interval [CI]: [.4 to .8]) and was no different than AVF after 1.2 years. (HR 1.6, CI: [.9 to 3.1]). On univariate analysis, dialysis catheters negatively impacted assisted primary patency (HR 1.4, CI: [1.09 to 1.77]). CONCLUSIONS: AVG can be maintained with higher rates of secondary patency in the short term and are no different in the long term. This result suggests that in patients with limited life expectancy an AVG may be an effective alternative to an AVF to reduce both catheter time and associated complications.

Heparin bonding does not improve patency of polytetrafluoroethylene arteriovenous grafts.

BACKGROUND: Heparin-bonded polytetrafluoroethylene (PTFE) grafts (hepPTFE) were developed to decrease rates of graft thrombosis. Our objective was to compare the patency of arteriovenous grafts (AVGs) for dialysis access with and without heparin bonding in a tertiary care setting. METHODS: Records of patients who had an AVG placed between January 2008 and June 2011 were retrospectively reviewed. Outcome measures were primary, assisted primary, and secondary patency. Marginal survival models (to account for correlation of accesses within subjects) using Cox proportional hazard regression were used for statistical comparisons. RESULTS: A total of 223 patients had 265 grafts placed. Of these, 62 (23%) were hepPTFE grafts. The average age was 66 ± 15 years in the hepPTFE group and 59 ± 17 years in the non-heparin-bonded control group (PTFE; P < 0.01). Of the hepPTFE group, 39% were men, 81% were African American, 63% were diabetic, and 81% had a tunneled catheter at the time of access placement. Of the PTFE group, 35% were men, 85% were African American, 56% were diabetic, and 83% had a tunneled catheter. HepPTFE grafts failed to improve rates of primary, assisted primary, or secondary patency based on univariate analysis (hazard ratio [HR]: 1.37 [95% confidence interval {CI}: 0.99-1.88]; HR: 1.39 [95% CI: 0.98-1.96]; and HR: 1.20 [95% CI: 0.73-1.96], respectively). The number of secondary interventions was similar in the 2 groups (1.1 interventions per person-year of follow-up PTFE versus 1.4 hepPTFE; P = 0.13). A multivariable model including age, diabetes, peripheral artery disease, tobacco use, previous access placement, and tunneled catheter found that the HR for hepPTFE was not significantly different than PTFE in primary, assisted primary, or secondary patency (HR: 1.32 [95% CI: 0.91-1.90]; HR: 1.35 [95% CI: 0.91-1.99]; and HR: 1.15 [95% CI: 0.62-2.16], respectively). CONCLUSIONS: hepPTFE AVGs failed to improve patency or decrease secondary interventions compared to standard PTFE grafts. Prospective studies are needed to confirm these results.

Pulse volume recording does not enhance segmental pressure readings for peripheral arterial disease stratification.

BACKGROUND: Noninvasive vascular laboratory determinations for peripheral arterial disease (PAD) often combine pulse volume recordings (PVRs), segmental pressure readings (SPs), and Doppler waveform traces (DWs) into a single diagnostic report. Our objective was to assess the corresponding diagnostic values for each test when subjected to interpretation by 4 vascular specialists. METHODS: A total of 2226 non-invasive diagnostic reports were reviewed through our institutional database between January 2009 and December 2011. Data from noninvasive records with corresponding angiograms performed within 3 months led to a cohort of 76 patients (89 limbs) for analysis. Four vascular specialists, blinded to the angiographic results, stratified the noninvasive studies as representative of normal, <50% "subcritical," or ≥50% "critical" stenosis at the upper thigh, lower thigh, popliteal, and calf segments using 4 randomized noninvasive modalities: (1) PVR alone; (2) SP alone; (3) SP+DW; and (4) SP+DW+PVR. The angiographic records were independently graded by another 3 evaluators and used as a standard to determine the noninvasive diagnostic values and interobserver agreements for each modality. Statistical tests used include the Fleiss-modified kappa analysis, Kruskal-Wallis analysis of variance with Dunn's multiple comparison test, the Kolmogorov-Smirnov test, and the unpaired t-test with Welch's correction. RESULTS: Interobserver variance for all modalities was high, except for SP. When surveying for any stenosis (<50% and ≥50%), sensitivity (range 25-75%) was lower than specificity (range 50-84%) for all modalities. When surveying for critical stenosis only (≥50%), sensitivity (range 27-54%) was also lower than specificity (range 68-92%). Accuracy for detecting any stenosis with SP+DW was significantly higher than with PVR alone (66 ± 7% vs. 56 ± 12%, P = 0.017). There was a significant reduction in accuracy when including incompressible readings within the SP-only analysis compared with exclusion of incompressible vessels (P = 0.0006). However, the effect of vessel incompressibility on accuracy was removed with the addition of DW (P = 0.17) to the protocol. CONCLUSIONS: SP has the greatest interobserver agreement in evaluation of PAD and can be used preferentially for PAD stratification. Given the lower accuracy of PVR for detecting either subcritical or critical disease, PVR tests can be omitted from the noninvasive vascular examination without a significant reduction in overall diagnostic value and can be reserved for patients with incompressible vessels.

Recognition and management of major vessel injury during laparoscopy.

Laparoscopy is one of the most commonly performed procedures in the United States. Injury to a major retroperitoneal vessel occurs in 0.3% to 1.0% of procedures, most commonly during laparoscopic entry while placing the Veress needle or primary trocar. Fatal outcome can be related to massive gas embolism or exsanguination. Recommended treatment for gas embolism can range from supportive measures to external chest compression and insertion of a central line to withdraw gas from the right side of the heart. Recommended treatment of major vessel injury with massive hemorrhage consists of rapid laparotomy and control of hemorrhage using direct pressure until a surgeon experienced in vascular procedures arrives. When a major vessel injury occurs in a surgical facility distant from a medical center and without an available surgeon with vascular experience, based on the trauma literature, we recommend temporary control of blood loss using abdominal packing and closure (i.e., "damage control surgery") and judicious resuscitation (i.e., "damage control resuscitation") before transportation to a medical center.