Prevalence of chronic opioid use in patients with peripheral arterial disease undergoing revascularization.

OBJECTIVE: Opiate use, dependence, and the associated morbidity and mortality are major current public health problems in the United States. Little is known about patterns of opioid use in patients with peripheral arterial disease (PAD). The purpose of this study was to identify the prevalence of chronic preoperative and postoperative prescription opioid use in patients with PAD. A secondary aim was to determine the demographic, comorbid conditions, and operative characteristics associated with chronic opioid use. METHODS: Using a single-institution database of patients with PAD undergoing open or endovascular lower extremity intervention from 2013 to 2014, data regarding opiate use and associated conditions were abstracted for analysis. Patients were excluded if they did not live in North Carolina or surgery was not for PAD. Preoperative (PreCOU) and postoperative chronic opioid use (PostCOU) were defined as consistent opioid prescription filling in the 3 months before and after the index procedure, respectively. Opioid prescription filling was assessed using the North Carolina Controlled Substance Reporting System. Demographics, comorbid conditions, other adjunct pain medication data, and operative characteristics were abstracted from our institutional electronic medical record. Associations with PreCOU were evaluated using the t test, Wilcoxon test, or two-sample median test (continuous), or the χ2 or Fisher exact tests (categorical). RESULTS: A total of 202 patients undergoing open (108; 53.5%) or endovascular (94; 46.5%) revascularization for claudication or critical limb ischemia were identified for analysis. The mean age was 64.6 years, and 36% were female. Claudication was the indication for revascularization in 26.7% of patients, and critical limb ischemia was the indication in 73.3% of patients. The median preoperative ankle-brachial index (ABI) was 0.50. Sixty-eight patients (34%) met the definition for PreCOU. PreCOU was associated with female gender, history of chronic musculoskeletal pain, benzodiazepine use, and self-reported illicit drug use. Less than 50% of patients reported use of non-opiate adjunct pain medications. No association was observed between PreCOU and pre- or postoperative ABI, or number of prior lower extremity interventions. Following revascularization, the median ABI was 0.88. PreCOU was not associated with significant differences in postoperative complications, length of stay, or mortality. Overall, 71 patients (35%) met the definition for PostCOU, 14 of whom had no history of preoperative chronic opiate use. Ten patients with PreCOU did not demonstrate PostCOU. CONCLUSIONS: Chronic opiate use was common in patients with PAD with a prevalence of approximately 35%, both prior to and following revascularization. Revascularization was associated with a termination of chronic opiate use in less than 15% of patients with PreCOU. Additionally, 10% of patients who did not use opiates chronically before their revascularization did so afterwards. Patients with PAD requiring intervention represent a high-risk group with regards to chronic opiate use. Increased diligence in identifying opioid use among patients with PAD and optimizing the use of non-narcotic adjunct pain medications may result in a lower prevalence of chronic opiate use and its attendant adverse effects.

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.

Outpatient grip strength measurement predicts survival, perioperative adverse events, and nonhome discharge among patients with vascular disease.

OBJECTIVES: Frailty is associated with adverse outcomes among patients with vascular disease. Grip strength measurement is a comparatively simple, quick, and inexpensive screening test for weakness (a component of frailty) that is potentially applicable to clinical practice. We hypothesized that grip strength and categorical weakness are associated with clinical outcomes among patients with vascular disease. To test this hypothesis, we conducted a longitudinal cohort study evaluating associations between grip strength measured during outpatient clinic visits for vascular disease and clinical outcomes, including survival and perioperative outcomes. METHODS: Adult patients recruited from outpatient vascular surgery and/or vascular medicine clinics underwent dominant hand grip strength measurement using a hand dynamometer. Participants were categorized as weak based on grip strength, sex, and body mass index. Multivariable logistic models were used to evaluate perioperative outcomes. Mortality was evaluated using Cox proportional hazards models adjusted for sex, age, and operative intervention during follow-up. RESULTS: We enrolled 321 participants. The mean patients age was 69.0 ± 9.4 years, and 33% were women. Mean grip strength was 32.0 ± 12.1 kg, and 92 participants (29%) were categorized as weak. The median follow-up was 24.0 months. Adverse perioperative events occurred in 32 of 84 patients undergoing procedures. Grip strength was associated with decreased risk of perioperative adverse events (hazard ratio [HR], 0.41 per 12.7 kg increase; 95% confidence interval [CI], 0.20-0.85; P = .0171) in a model adjusted for open versus endovascular procedure (HR, 12.75 for open; 95% CI, 2.54-63.90; P = .0020) and sex (HR, 3.05 for male; 95% CI, 0.75-12.4; P = .120). Grip strength was also associated with a lower risk of nonhome discharge (HR, 0.34 per 12.7 kg increase; 95% CI, 0.14-0.82; P = .016) adjusted for sex (HR, 2.14 for male; 95% CI, 0.48-9.50; P = .31) and open versus endovascular procedure (HR, 10.36 for open; 95% CI, 1.20-89.47; P = .034). No associations between grip strength and length of stay were observed. Mortality occurred in 48 participants (14.9%) during follow-up. Grip strength was inversely associated with mortality (HR, 0.46 per 12.5 kg increase; 95% CI, 0.29-0.73; P = .0009) in a model adjusted for sex (HR, 5.08 for male; 95% CI, 2.1-12.3; P = .0003), age (HR, 1.04 per year; 95% CI, 1.01-1.08), and operative intervention during follow-up (HR, 1.23; 95% CI, 0.71-2.52). Categorical weakness was also associated with mortality (HR, 1.81 vs nonfrail; P = .048) in a model adjusted for age (HR, 1.06 per year; P = .002) and surgical intervention (HR, 1.36; 95% CI, 1.02-0.09; P = .331). CONCLUSIONS: Grip strength is associated with all-cause mortality, perioperative adverse events, and nonhome discharge among patients with vascular disease. These observations support the usefulness of grip strength as a simple and inexpensive risk screening tool for patients with vascular disease.

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.

The Effects of Case Timing and Care Team Composition on Hospital Operating Room Costs for Endovascular Procedures.

BACKGROUND: The contemporary healthcare environment is complex with mounting pressures to perform greater procedural volumes with less support staff to minimize costs and maximize efficiency. This report details an analysis of routine endovascular procedures performed with dedicated vascular support staff during daytime hours compared to similar cases performed after hours with general operating room staff. METHODS: All lower extremity endovascular cases over a 37-month period were identified using Current Procedural Terminology codes from a query of our institutional database. Emergent/urgent cases and cases with associated open surgical procedures were excluded. Cases were divided according to the time of day and available clinical support structure according to procedure start time: specialty-specific daytime (SS) and general staff after hours for all others (AH). The resulting case list was examined by case type according to SS or AH designation and case types occurring disproportionately during either time frame were excluded to create a homogenous group of cases. Demographics, case specifics, and cost data were then obtained from the electronic health record and our enterprise cost data warehouse. Multivariable mixed linear modeling was used to examine component costs (i.e., anesthesia, supplies, etc.) and total costs controlling for a number of factors that could affect cost. RESULTS: Two hundred fifty-two routine endovascular-only procedures were examined in 232 patients (190 SS, 42 AH). No significant differences in procedure specifics were observed between the groups [number and location of access site(s), indication for procedure, type and number of interventions, etc.]. Multivariable analyses controlled for factors affecting costs. Costs associated with anesthesia (cost ratio 1.90, P = 0.001), operating room time costs (cost ratio 1.29, P = 0.03), and post anesthesia recovery (cost ratio 1.23, P = 0.004) were all significantly increased in AH cases compared to SS cases. The average total hospital cost for routine endovascular cases that performed AH was $8,095 compared to $5,636 for SS cases (cost ratio 1.44, P = 0.008). CONCLUSIONS: Performance of routine endovascular cases was associated with significantly less cost to the hospital system when performed by SS teams during regular hospital hours with a ∼30% increase in total cost associated with AH cases. In the current healthcare environment, investments in SS teams and process improvements are likely to be cost effective.

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.

Grip strength measurement for frailty assessment in patients with vascular disease and associations with comorbidity, cardiac risk, and sarcopenia.

OBJECTIVE: Frailty is associated with adverse events, length of stay, and nonhome discharge after vascular surgery. Frailty measures based on walking-based tests may be impractical or invalid for patients with walking impairment from symptoms or sequelae of vascular disease. We hypothesized that grip strength is associated with frailty, comorbidity, and cardiac risk among patients with vascular disease. METHODS: Dominant hand grip strength was measured during ambulatory clinic visits among patients with vascular disease (abdominal aortic aneurysm [AAA], carotid stenosis, and peripheral artery disease [PAD]). Frailty prevalence was defined on the basis of the 20th percentile of community-dwelling population estimates adjusted for age, gender, and body mass index. Associations between grip strength, Charlson Comorbidity Index (CCI), Revised Cardiac Risk Index (RCRI), and sarcopenia (based on total psoas area for patients with cross-sectional abdominal imaging) were evaluated using linear and logistic regression. RESULTS: Grip strength was measured in 311 participants; all had sufficient data for CCI calculation, 217 (69.8%) had sufficient data for RCRI, and 88 (28.3%) had cross-sectional imaging permitting psoas measurement. Eighty-six participants (27.7%) were categorized as frail on the basis of grip strength. Frailty was associated with CCI (odds ratio, 1.86; 95% confidence interval, 1.34-2.57; P = .0002) in the multivariable model. Frail participants also had a higher average number of RCRI components vs nonfrail patients (mean ± standard deviation, 1.8 ± 0.8 for frail vs 1.5 ± 0.7 for nonfrail; P = .018); frailty was also associated with RCRI in the adjusted multivariable model (odds ratio, 1.75; 95% confidence interval, 1.16-2.64; P = .008). Total psoas area was lower among patients categorized as frail vs nonfrail on the basis of grip strength (21.0 ± 6.6 vs 25.4 ± 7.4; P = .010). Each 10 cm2 increase in psoas area was associated with a 5.7 kg increase in grip strength in a multivariable model adjusting for age and gender (P < .0001). Adjusted least squares mean psoas diameter estimates were 25.5 ± 1.1 cm2 for participants with AAA, 26.7 ± 2.0 cm2 for participants with carotid stenosis, and 22.7 ± 0.8 cm2 for participants with PAD (P = .053 for PAD vs AAA; P = .057 for PAD vs carotid stenosis; and P = .564 for AAA vs carotid stenosis). CONCLUSIONS: Grip strength is useful for identifying frailty among patients with vascular disease. Frail status based on grip strength is associated with comorbidity, cardiac risk, and sarcopenia in this population. These findings suggest that grip strength may have utility as a simple and inexpensive risk screening tool that is easily implemented in ambulatory clinics, avoids the need for imaging, and overcomes possible limitations of walking-based measures. Lower mean psoas diameters among patients with PAD vs other diagnoses may warrant consideration of specific approaches to morphomic analysis.

Superior Lower Extremity Vein Graft Bypass Patency among Married Patients with Peripheral Artery Disease.

BACKGROUND: Outcome disparities associated with lower extremity bypass (LEB) for peripheral artery disease (PAD) have been identified but are poorly understood. Marital status may affect outcomes through factors related to health risk behaviors, adherence, and access to care but has not been characterized as a predictor of surgical outcomes and is often omitted from administrative data sets. We evaluated associations between marital status and vein graft patency following LEB using multivariable models adjusting for established risk factors. METHODS: Consecutive patients undergoing autogenous LEB for PAD were identified and analyzed. Survival analysis and Cox proportional hazards models were used to evaluate patency stratified by marital status (married versus single, divorced, or widow[er]) adjusting for demographic, comorbidity, and anatomic factors in multivariable models. RESULTS: Seventy-three participants who underwent 79 autogenous vein LEB had complete data and were analyzed. Forty-three patients (58.9%) were married, and 30 (41.1%) were unmarried. Compared with unmarried patients, married patients were older at the time of their bypass procedure (67.3 ± 10.8 years vs. 62.2 ± 10.6 years; P = 0.05). Married patients also had a lower prevalence of female gender (11.6% vs. 33.3%; P = 0.02). Diabetes, hypertension, hyperlipidemia, and smoking were common among both married and unmarried patients. Minimum great saphenous vein conduit diameters were larger in married versus unmarried patients (2.82 ± 0.57 mm vs. 2.52 ± 0.65 mm; P = 0.04). Twenty-four-month primary patency was 66% for married versus 38% for unmarried patients. In a multivariable proportional hazards model adjusting for proximal and distal graft inflow/outflow, medications, gender, age, race, smoking, diabetes, and minimum vein graft diameter, married status was associated with superior primary patency (hazard ratio [HR] = 0.33; 95% confidence limits [0.11, 0.99]; P = 0.05); other predictive covariates included preoperative antiplatelet therapy (HR = 0.27; 95% confidence limits [0.10, 0.74]; P = 0.01) and diabetes (HR = 2.56; 95% confidence limits [0.93-7.04]; P = 0.07). CONCLUSIONS: Marital status is associated with vein graft patency following LEB. Further investigation into the mechanistic explanation for improved patency among married patients may provide insight into social or behavioral factors influencing other disparities associated with LEB outcomes.

Endovascular Treatment of Chronic Mesenteric Ischemia in the Setting of Occlusive Superior Mesenteric Artery Lesions.

BACKGROUND: Endovascular intervention is considered the first-line treatment for chronic mesenteric ischemia (CMI) when feasible. Two-vessel revascularization is most definitive when celiac (CA) and superior mesenteric arteries (SMA) are diseased, but single-vessel intervention may be performed in patients with 2-vessel disease due to anatomic/technical factors. We evaluated anatomic predictors of clinical outcomes associated with endovascular treatment of CMI among patients with occlusive SMA lesions. METHODS: Patients with CMI treated with endovascular revascularization over 10 years were identified. Patients with SMA occlusions were selected for analysis. Between-group comparisons based on inclusion of an SMA revascularization were evaluated using t-test and chi-squared test. Freedom from symptomatic recurrence or repeat intervention was analyzed using proportional hazards regression. RESULTS: Fifty-four patients with CMI were analyzed. Sixteen (29.6%) patients had CA-only intervention, and 38 (70.4%) patients had SMA revascularization with or without CA intervention. No significant differences in demographics or comorbidity were identified between groups. In the CA-only intervention group, 8 of the 16 (50%) patients developed symptomatic recurrence compared with 8 of the 31 (21.1%) patients whose intervention included the SMA. Patients treated without SMA intervention also had decreased freedom from both symptomatic recurrence (hazard ratio [HR] 3.2, 95% confidence interval [CI] 1.2-8.6, P = 0.016) and repeat intervention (HR 5.5, 95% CI 1.8-16.3, P = 0.001). CONCLUSIONS: Among patients with CMI and occlusive SMA lesions, SMA revascularization appears to be the key determinant for symptomatic outcomes and repeat intervention. Patient counseling should include potential future need for surgical revascularization if endovascular SMA treatment cannot be accomplished.

Gender-specific Differences in Great Saphenous Vein Conduit. A Link to Lower Extremity Bypass Outcomes Disparities?

BACKGROUND: Inferior lower extremity bypass (LEB) outcomes have been reported among women with peripheral arterial disease (PAD), but the mechanisms responsible for this disparity are unknown. Great saphenous vein (GSV) is considered the conduit of choice for LEB; GSV diameter is associated with graft patency and therefore is often used as a criterion for suitability for use as bypass conduit. We hypothesized that gender-based differences in GSV may contribute to LEB outcomes disparities. To explore this hypothesis, we performed a gender-based analysis of GSV anatomic characteristics among patients with PAD who were studied with duplex ultrasound vein mapping during evaluation for LEB. METHODS: Consecutive patients undergoing ultrasound vein mapping for planned LEB were analyzed. Minimum above- and below-knee GSV diameters were obtained in addition to demographic, procedural, and clinical data. Associations between gender and GSV diameter were evaluated using multivariate mixed models adjusting for anatomic location and within-patient correlation. RESULTS: One hundred five patients were analyzed. Mean patient age was 65 ± 11 years, 25% were women, and 78% were white. Mixed model estimates of minimum GSV diameters were 3.14 ± 0.09 mm above knee and 2.74 ± 0.09 below knee for men versus 3.23 ± 0.14 above-knee and 2.49 ± 0.14 below knee for women. A gender-based interaction between anatomic location and GSV diameter was identified, with women having a greater difference between above- and below-knee GSV diameters (or taper; mean difference of 0.73 ± 0.12 vs. 0.41 ± 0.17 mm; P = 0.017). CONCLUSIONS: GSV taper (difference between above- and below-knee diameters) is greater in women and may contribute to inferior patency after LEB with vein conduit, particularly for below-knee target vessels. Further research is necessary to evaluate specific hemodynamic effects of graft taper and links with other clinical endpoints. In addition to minimum diameter, vein graft taper may warrant consideration when planning LEB.

Perceptions of Integrated Vascular Surgery Fellowship Graduates among Community Vascular Surgeons.

BACKGROUND: Vascular training includes both integrated residency ("0+5") and postresidency fellowship ("5+2") programs. The impact of training models on attitudes toward graduates as prospective hires is incompletely understood, and existing studies have primarily surveyed surgeons from academic centers. We surveyed surgeons who were in active clinical practice but not affiliated with a medical school or training program to compare perceptions of integrated versus postgraduate programs. METHODS: Vascular surgeons not affiliated with a university-based practice were identified from membership rosters of one regional and one national specialty society and e-mailed an anonymous survey. The survey evaluated respondents' training, practice distribution, general surgery responsibilities, hiring practices, and perception of the integrated and postgraduate trained vascular surgeons. Agreement among specific responses was evaluated using McNemar's test. RESULTS: The survey was sent to 406 surgeons with 71 (17.5%) responding. A total of 42% of respondents indicated that half or more of their cases consisted of open procedures and 10% reported general surgery coverage as part of their practice. More respondents indicated that they consider postgraduate trained surgeons very mature (41% vs. 7%, P < 0.0001) and better prepared for open cases (89% vs. 28%, P < 0.0001), as well as endovascular cases (96% vs. 87%, P = 0.0339). Overall 84% stated that they would interview an integrated program graduate, although only 72% indicated that they would hire one. Overall 16.9% identified ability to cover general surgery as either very important or somewhat important characteristic for a potential hire. CONCLUSIONS: Perceptions of 5+2 graduates as more mature and better prepared for opens surgical cases may influence hiring practices. This suggests that attitudes toward integrated versus 5+2 trained surgeons may differ between academic and community vascular surgeons. Further research is needed to assess whether these differences are related to actual differences in graduate skills, familiarity with integrated graduates, or other factors.

Chronic diuretic therapy attenuates renal BOLD magnetic resonance response to an acute furosemide stimulus.

BACKGROUND: Blood Oxygen Level Dependent (BOLD) magnetic resonance (MR) is a novel imaging tool that detects changes in tissue oxygenation. Increases in renal oxygenation in response to a standard 20 mg intravenous furosemide stimulus have been evaluated to assess kidney viability in patients with renal artery stenosis (RAS). The effect of prior exposure to furosemide on the ability of BOLD MR techniques to evaluate renal function is unknown.This study tested the hypothesis that chronic loop diuretic therapy is associated with attenuated responses in renal tissue oxygenation as measured by BOLD MR with an acute 20 mg intravenous furosemide stimulus in participants undergoing evaluation for RAS. METHODS: Thirty-eight participants referred for evaluation of RAS were recruited for this study. We examined renal cortical and medullary BOLD signal (T2*) intensities before and after a 20 mg intravenous furosemide stimulus. Additionally, we measured changes in renal artery blood flow using phase contrast techniques. RESULTS: After controlling for covariates age, race, gender, diabetes, glomerular filtration rate, body mass index, and stenosis severity, daily oral furosemide dose was an independent, negative predictor of renal medullary T2* response (p=0.01) to a standard 20 mg intravenous furosemide stimulus. Stenosis severity and ethnicity were also significant independent predictors of changes in T2* signal intensity in response to an acute furosemide challenge. Changes in renal blood flow in response to acute furosemide administration were correlated with changes in T2* in the renal cortex (r=0.29, p=0.03) but not the medulla suggesting changes in renal medullary oxygenation were not due to reduced renal medullary blood flow. CONCLUSIONS: Chronic furosemide therapy attenuates BOLD MR responses to an acute furosemide stimulus in patients with RAS being evaluated for renal artery revascularization procedures. Thus, patients who are chronically administered loop diuretics may need a different dosing strategy to accurately detect changes in renal oxygenation with BOLD MR in response to a furosemide stimulus.

Influence of computed tomography angiography reconstruction software on anatomic measurements and endograft component selection for endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Three-dimensional (3D) centerline reconstruction of computed tomography angiography (CTA) images permits detailed anatomic characterization of abdominal aortic aneurysms and facilitates planning of endovascular repair. Although several programs for 3D CTA reconstruction and measurement are available, direct comparisons have not been published, and reliability between software platforms has not been characterized. We evaluated agreement between anatomic measurements obtained from 3D CTA reconstructions using three commercially available software programs and characterized concordance between the programs for endograft component selection. METHODS: Images from 92 CTA studies performed before abdominal aortic aneurysm repair were reconstructed and measured using three different software programs: independent reconstruction with proprietary software (Preview; M2S Inc, Lebanon, NH), surgeon-based reconstruction with proprietary software (AquariusNet Thin Client; TeraRecon Inc, San Mateo, Calif), and surgeon-based reconstruction with open-source software (Osirix MD; Pixmeo, Geneva, Switzerland). Agreement between outer wall diameter and length measurements obtained from centerline reconstructions created with each program was evaluated using scatter plots, intraclass correlation coefficients, and Bland-Altman plots. Concordance between aortic and iliac endograft component diameters selected from measurements with each program based on published instructions for use was examined using weighted κ statistics. RESULTS: Diameter measurements were generally similar between programs. Mean diameters at all locations were within ≤ 1 mm of one another, and mean length measurements were within ≤ 10 mm of one another for all pairwise comparisons. Intraclass correlations coefficients between programs for diameter measurements were comparable between programs (≥ 0.82 for all diameter comparisons and ≥ 0.88 for all length comparisons) and indicated good correlation. Pair-wise comparisons indicated similar rates of identical and adjacent size endograft component selection without an obvious trend toward superior agreement for any two programs. Rates of identical proximal endograft diameter selection ranged from 46% to 59%, whereas 89% to 100% of proximal endograft diameters selected between programs were within one adjacent (smaller or larger) size of each other. For iliac endograft selection, rates of identical component diameter selection between programs ranged from 36% to 69%, and 58% to 99% of selected iliac endograft diameters were within one adjacent size. CONCLUSIONS: Outer wall diameter and centerline length measurements obtained from 3D CTA reconstructions demonstrated good correlation between imaging analysis software programs, and graft diameter selections based on these measurements were reasonably similar. Comparable 3D CTA reconstruction measurements can be generated from independent and surgeon-based approaches using proprietary and open-source software, and the selection of a method to interpret images for endograft planning can be individualized according to operator experience and available resources while retaining sufficient accuracy.

Early duplex predicts restenosis after renal artery angioplasty and stenting.

OBJECTIVE: To examine the relationship between early renal duplex sonography (RDS) and restenosis after primary renal artery percutaneous angioplasty and stenting (RA-PTAS). METHODS: Consecutive patients undergoing RA-PTAS for hemodynamically significant atherosclerotic renal artery stenosis with hypertension and/or ischemic nephropathy between September 2003 and July 2010 were identified from a prospective registry. Patients had renal RDS pre-RA-PTAS, within 1 week of RA-PTAS and follow-up RDS examinations after the first postoperative week for surveillance of restenosis. Restenosis was defined as a renal artery peak systolic velocity (PSV) ≥ 180 cm/s on follow-up RDS. Associations between RDS and restenosis were examined using proportional hazards regression. RESULTS: Eighty-three patients (59% female; 12% nonwhite; mean age, 70 ± 10 years; mean pre-RA-PTAS PSV, 276 ± 107 cm/s) undergoing 91 RA-PTAS procedures comprised the sample for this study. All procedures included a completion arteriogram demonstrating no significant residual stenosis. Mean follow-up time was 14.9 ± 10.8 months. Thirty-four renal arteries (RAs) demonstrated restenosis on follow-up with a median time to restenosis of 8.7 months. There was no significant difference in the mean PSV pre-RA-PTAS in those with and without restenosis (287 ± 96 cm/s vs 269 ± 113 cm/s; P = .455), and PSV pre-RA-PTAS was not predictive of restenosis. Within 1 week of RA-PTAS, mean renal artery PSV differed significantly for renal arteries with and without restenosis (112 ± 27 cm/s vs 91 ± 34 cm/s; P = .003). Proportional hazards regression analysis demonstrated increased PSV on first post-RA-PTAS RDS was significantly and independently associated with subsequent restenosis during follow-up (hazard ratio for 30 cm/s increase, 1.81; 95% confidence interval, 1.32-2.49; P = .0003). There was no difference in pre- minus postprocedural PSV in those with and without restenosis on follow-up (175 ± 104 cm/s vs 179 ± 124 cm/s; P = .88), nor was this associated with time to restenosis. Best subsets model selection identified first postprocedural RDS as the only factor predictive of follow-up restenosis. A receiver-operating characteristic curve was examined to assess the first week PSV post-RA-PTAS most predictive of restenosis during follow-up. The ideal cut point for RA-PSV was 87 cm/s or greater. This value was associated with a sensitivity of 82.4%, specificity of 52.6%, and area under the receiver-operating characteristic curve of 69.3%. Increased first postprocedural RA-PSV was predictive of lower estimated glomerular filtration rate in the first 2 years after the procedure (-1.6 ± 0.7 mL/min/1.73 m(2) lower estimated glomerular filtration rate per 10 cm/s increase in RA-PSV; P = .010). CONCLUSIONS: Early renal artery PSV within 1 week after RA-PTAS predicted renal artery restenosis and lower postprocedure renal function. Recurrent stenosis demonstrated no association with absolute elevation in PSV prior to RA-PTAS nor with the change in PSV after RA-PTAS. These data suggest that detectable differences exist in renal artery flow parameters following RA-PTAS that are predictive of restenosis during follow-up but are not apparent on completion arteriography or detectable by intra-arterial pressure measurements. Further study is warranted.