Hybrid fibroin/polyurethane small-diameter vascular grafts: from fabrication toin vivopreliminary assessment.

To address the need of alternatives to autologous vessels for small-calibre vascular applications (e.g. cardiac surgery), a bio-hybrid semi-degradable material composed of silk fibroin (SF) and polyurethane (Silkothane®) was herein used to fabricate very small-calibre grafts (Øin= 1.5 mm) via electrospinning. Bio-hybrid grafts werein vitrocharacterized in terms of morphology and mechanical behaviour, and compared to similar grafts of pure SF. Similarly, two native vessels from a rodent model (abdominal aorta and vena cava) were harvested and characterized. Preliminary implants were performed on Lewis rats to confirm the suitability of Silkothane® grafts for small-calibre applications, specifically as aortic insertion and femoral shunt. The manufacturing process generated pliable grafts consisting of a randomized fibrous mesh and exhibiting similar geometrical features to rat aortas. Both Silkothane® and pure SF grafts showed radial compliances in the range from 1.37 ± 0.86 to 1.88 ± 1.01% 10-2mmHg-1, lower than that of native vessels. The Silkothane® small-calibre devices were also implanted in rats demonstrating to be adequate for vascular applications; all the treated rats survived the surgery for three months after implantation, and 16 rats out of 17 (94%) still showed blood flow inside the graft at sacrifice. The obtained results lay the basis for a deeper investigation of the interaction between the Silkothane® graft and the implant site, which may deal with further analysis on the potentialities in terms of degradability and tissue formation, on longer time-points.

Cell Viability Assessment Using Fluorescence Vital Dyes and Confocal Microscopy in Evaluating Freezing and Thawing Protocols Used in Cryopreservation of Allogeneic Venous Grafts.

The authors present their contribution to the improvement of methods suitable for the detection of the freezing and thawing damage of cells of cryopreserved venous grafts used for lower limb revascularization procedures. They studied the post-thaw viability of cells of the wall of cryopreserved venous grafts (CVG) immediately after thawing and after 24 and 48 h culture at +37 °C in two groups of six CVG selected randomly for slow thawing in the refrigerator and rapid thawing in a water bath at +37 °C. The grafts were collected from multi-organ and tissue brain-dead donors, cryopreserved, and stored in a liquid nitrogen vapor phase for five years. The viability was assessed from tissue slices obtained by perpendicular and longitudinal cuts of the thawed graft samples using in situ staining with fluorescence vital dyes. The mean and median immediate post-thaw viability values above 70% were found in using both thawing protocols and both types of cutting. The statistically significant decline in viability after the 48-h culture was observed only when using the slow thawing protocol and perpendicular cutting. The possible explanation might be the "solution effect damage" during slow thawing, which caused a gentle reduction in the graft cellularity. The possible influence of this phenomenon on the immunogenicity of CVG should be the subject of further investigations.

Saphenous vein valve assessment utilizing upright CT to potentially improve graft assessment for bypass surgery.

Saphenous veins (SVs) are frequently employed as bypass grafts. The SV graft failure is predominantly seen at the valve site. Avoiding valves during vein harvest would help reduce graft failure. We endeavored to detect SV valves, tributaries, and vessel size employing upright computed tomography (CT) for the raw cadaver venous samples and in healthy volunteers. Five cadaver legs were scanned. Anatomical analysis showed 3.0 (IQR: 2.0-3.0) valves and 13.50 (IQR: 10.00-16.25) tributaries. The upright CT completely detected, compared to 2.0 (IQR: 1.5-2.5, p = 0.06) valves and 9.5 (IQR: 7.5-13.0, p = 0.13) tributaries by supine CT. From a total of 190 volunteers, 138 (men:75, women:63) were included. The number of valves from the SF junction to 35 cm were significantly higher in upright CT than in supine CT bilaterally [upright vs. supine, Right: 4 (IQR: 3-5) vs. 2 (IQR:1-2), p < 0.0001, Left: 4 (IQR: 3-5) vs. 2 (IQR: 1-2), p < 0.0001]. The number of tributaries and vessel areas per leg were also higher for upright compared with supine CT. Upright CT enables non-invasive detection of SV valves, tributaries, and vessel size. Although not tested here, it is expected that upright CT may potentially improve graft assessment for bypass surgery.

Outcome of Femoral-popliteal Bypass Procedures in Different Ethnic Groups in England: A Retrospective Analysis of Hospital Episode Statistics.

BACKGROUND: Previous studies, mainly from the United States, have reported worse outcomes from lower limb bypass procedures in ethnic minority populations. Limited nationwide data are available from ethnic minority populations from Europe. The aim of this study is to investigate outcomes from lower limb bypass procedures in ethnic minorities from England. METHODS: We enquired the "Hospital Episode Statistics" database, using ICD-10 codes to identify all cases of femoral-popliteal bypass operations from English NHS Hospitals from 01/01/2006 to 31/12/2015. Every case was followed up for 2 years for subsequent events. The primary outcomes were mortality and major leg amputation. Patients were broadly categorised according to Black, Asian and White ethnicity. Chi-square test was used to the ethnic groups and odds ratios (OR) were calculated using White ethnic group with the largest numbers of participants as a reference category. RESULTS: In the examined 10-year period, 20825 femoral-popliteal bypass procedures (250 of Black, 167 of Asian, and 20.408 of White ethnicity) were recorded. Thirty-day and 2-year mortality were 2.8% and 16.8% with no significant ethnic differences. Patients of Black ethnicity had higher risk of limb loss compared to Whites (23.2% vs. 15.6%, OR = 1.63, 95% confidence interval (CI) 1.21-2.19, P < 0.01). There was no significant difference in amputation rates between Asians and Whites (16.2% vs.. 15.6%, P = 0.94). CONCLUSIONS: Patients of Black ethnicity are at higher risk of limb loss after a femoropopliteal bypass procedure. Further research is needed to identify the causes of this discrepancy.

Impact of Bypass Flow Assessment on Long-Term Outcomes in Patients with Chronic Limb-Threatening Ischemia.

BACKGROUND: Transit time flow meter (TTFM) allows quick and accurate intraoperative graft assessment. The main study goal is to evaluate the influence of graft flow measurements on long-term clinical outcomes in patients with chronic limb-threatening ischemia (CLTI) undergoing bellow the knee (BTK) vein bypass surgery. METHODS: Between January 1st, 1999 and January 1st, 2006, 976 CLTI consecutive patients underwent lower extremity bypass surgery. When applying the exclusion criteria, 249 patients were included in the final analysis. Control measurements were performed at the end of the procedure. Patients were divided according to the mean (more/less than 100 ml/min) and diastolic graft flow (more/less than 40 ml/min) values in four groups. The primary endpoints were a major adverse limb event (male) and primary graft patency. RESULTS: After the median follow-up of 68 months, a group with the mean graft flow below 100 ml/min and the diastolic graft flow below 40 ml/min had the highest rates of male (χ2 = 36.60, DF = 1, P < 0.01, log-rank test) and the worst primary graft patency (χ2 = 53.05, DF = 1, P < 0.01, log-rank test). CONCLUSION: In patients with CLTI undergoing BTK vein bypass surgery, TTFM parameters, especially combined impact of mean graft flow less than 100 ml/min and diastolic graft flow less than 40 ml/min, were associated with an increased risk of poor long-term male and primary graft patency.

Single Photon Emission Tomography in the Diagnostic Assessment of Cardiac and Vascular Infectious Diseases.

Cardiac and vascular infection is an arising cause of mortality and morbidity in the adult population. Diagnosis based on culture and anatomic imaging are frequently inconclusive. Radiolabeled leucocyte scintigraphy plays a useful role in the diagnosis and management of these serious infectious conditions. In this paper, we present an update on the diagnostic performance of single- photon emission tomographic (SPECT) techniques using different radionuclides in the management of patients with cardiac and vascular infections. We performed a thorough search of recent literature on the topic. We present a discussion on the clinical utility of different SPECT tracers in cardiac and vascular infections, including infective endocarditis, cardiac implantable electronic device (CIED) infections, left ventricular assist device infection, and vascular graft infection. Radionuclide technique using SPECT tracers is a useful imaging modality in the diagnosis of cardiac infection. Among the different SPECT tracers for infection imaging, radiolabeled leucocyte scintigraphy is currently the most useful tool in the diagnosis and management of patients with suspected cardiac and vascular infection. Radiolabeled leucocyte scintigraphy has a high specificity, a result of the ability of the leucocytes to accumulate as sites of pyogenic infection but not at sites of sterile inflammation such as seen in the early post-operative period or in response to the presence of a prosthetic cardiac or vascular material. Limited experience with radiotracers for in vivo labelling of leucocytes such as 99mTc-sulesomab and 99mTc-besilesomab show acceptable diagnostic performance without the need for the tedious process of ex-vivo labeling. 67Ga scintigraphy used to be popular for cardiac and vascular infection imaging. Its use has run out of favor following the availability of more effective molecular imaging methods. SPECT techniques with radiolabeled leucocyte scintigraphy has a high diagnostic performance in the evaluation of patients with suspected cardiac or vascular infection. It is able to confirm or reject the presence of infection when results of anatomic imaging or culture remain inconclusive. Its diagnostic performance is not compromised by sterile inflammation occurring in the early post-operative period or in response to implanted prosthetic materials.

Quantifying the risk-adjusted hospital costs of postoperative complications after lower extremity bypass in patients with claudication.

OBJECTIVE: Increasing evidence has shown that the risks associated with surgical revascularization for intermittent claudication outweigh the benefits. The aim of our study was to quantify the cost of care associated with perioperative complications after elective lower extremity bypass (LEB) in patients presenting with intermittent claudication. METHODS: All patients undergoing first-time LEB for claudication in the Healthcare Database (2009-2015) were included. The primary outcome was in-hospital postoperative complications, including major adverse limb events (MALE), major adverse cardiac events (MACE), acute kidney injury, and wound complications. The overall crude hospital costs are reported, and a generalized linear model with log link and inverse Gaussian distribution was used to calculate the predicted hospital costs for specific complications. RESULTS: Overall, 7154 patients had undergone elective LEB for claudication during the study period. The median age was 66 years (interquartile range, 59-73 years), 67.5% were male, and 75.3% were white. Two thirds of patients (61.2%) had Medicare insurance, followed by private insurance (26.9%), Medicaid (7.7%), and other insurance (4.2%). In-hospital complications occurred in 8.5% of patients, including acute kidney injury in 3.0%, MALE in 2.8%, wound complications in 2.3%, and MACE in 1.0%. The overall median crude hospital cost was $11,783 (interquartile range, $8911-$15,767) per patient. The incremental increase in cost associated with a postoperative complication was significant, ranging from $6183 (95% confidence interval, $4604-$7762) for MALE to $10,485 (95% confidence interval, $6529-$14,441) for MACE after risk adjustment. CONCLUSIONS: Postoperative complications after elective LEB for claudication are not uncommon and increase the in-hospital costs by 46% to 78% depending on the complication. Surgical revascularization for claudication should be used sparingly in carefully selected patients.

Immediate postoperative hyperglycemia after peripheral arterial bypass is associated with short-term and long-term poor outcomes.

OBJECTIVE: Although the impact of poorly controlled diabetes on surgical outcomes of patients undergoing lower extremity revascularization is well-known, it is not clear if immediate postoperative hyperglycemia (IPH) itself can be used as a surrogate for poor outcomes after peripheral arterial bypass. We sought to examine the effect of IPH in this patient population with its impact on short-term and long-term outcomes. METHODS: Retrospective review was completed for 505 patients who underwent either suprainguinal bypass surgery or infrainguinal bypass surgery between July 2002 and April 2018 for the treatment of peripheral arterial disease. All patients were undergoing first-time open bypass grafting. Patients were stratified into those who were normoglycemic or hyperglycemic (glucose ≥ 140 mg/dL) within 24 hours after surgery. A comparative analysis was performed on comorbidities and outcomes. RESULTS: Of 505 patients who underwent bypass grafting, 255 patients (50.5%) were hyperglycemic. The mean age of patients was 63.5 ± 14.1 years. The median follow-up was 5.2 years (range, 0.0-15.2 years). The distribution of procedures was as follows: femoral to popliteal bypasses (29%), femoral to femoral bypasses (17%), femoral to tibial bypasses (12%), aortobifemoral bypasses (10%), iliofemoral bypasses (9%), and axillofemoral bypasses (7%). At 30 days, hyperglycemic patients had an increased incidence of limb loss (8.3% vs 4.0%) and myocardial infarction (4.8% vs 0.8%) and incurred higher costs of hospital stay ($27,701 vs $22,990) (all P < .05). At 10 years, these patients had a higher incidence of needing major amputations (15.4% vs 9.4%; P = .025). Hyperglycemia after infrainguinal bypass was associated with nearly twice the risk of limb loss at 5 years (hazard ratio, 1.91; P = .034). Among the cohort of patients who required major amputations, the time duration between index revascularization and amputation was significantly shorter as compared with normoglycemic patients (P = .003). CONCLUSIONS: In this single-institution study with long-term follow-up, IPH was associated with increased rates of 30-day amputation and myocardial infarction, as well as an increased cost of hospital stay. In the long term, postoperative hyperglycemia was associated with greater major limb loss. Among the cohort of patients who required major amputations, the time period between revascularization and amputation was shorter for those patients who had IPH. IPH is an independent marker for poor outcomes after lower extremity revascularization procedures.

Assessment of a long-term in vitro model to characterize the mechanical behavior and macrophage-mediated degradation of a novel, degradable, electrospun poly-urethane vascular graft.

An assessment tool to evaluate the degradation of biodegradable materials in a more physiological environment is still needed. Macrophages are critical players in host response, remodeling and degradation. In this study, a cell culture model using monocyte-derived primary macrophages was established to study the degradation, macro-/micro-mechanical behavior and inflammatory behavior of a new designed, biodegradable thermoplastic polyurethane (TPU) scaffold, over an extended period of time in vitro. For in vivo study, the scaffolds were implanted subcutaneously in a rat model for up to 36 weeks. TPU scaffolds were fabricated via the electrospinning method. This technique provided a fibrous scaffold with an average fiber diameter of 1.39 ± 0.76 µm and an average pore size of 7.5 ± 1.1 µm. The results showed that TPU scaffolds supported the attachment and migration of macrophages throughout the three-dimensional matrix. Scaffold degradation could be detected in localized areas, emphasizing the role of adherent macrophages in scaffold degradation. Weight loss, molecular weight and biomechanical strength reduction were evident in the presence of the primary macrophage cells. TPU favored the switch from initial pro-inflammatory response of macrophages to an anti-inflammatory response over time both in vitro and in vivo. Expression of MMP-2 and MMP-9 (the key enzymes in tissue remodeling based on ECM modifications) was also evident in vitro and in vivo. This study showed that the primary monocyte-derived cell culture model represents a promising tool to characterize the degradation, mechanical behavior as well as biocompatibility of the scaffolds during an extended period of observation.

Medicare reimbursement of lower extremity bypass does not cover cost of care for most patients with critical limb ischemia.

OBJECTIVE: Lower extremity bypass surgery remains an important treatment option for patients with critical limb ischemia (CLI), but is resource intensive. We sought to evaluate the cost and Medicare reimbursement for lower extremity bypass surgery in patients with CLI. METHODS: Hospital cost accounting systems were queried for total technical and professional costs incurred and reimbursement received for patients with CLI undergoing lower extremity bypass at our center between 2011 and 2017. Patients were identified by assignment to Diagnosis-Related Group (DRG) 252, 253, or 254 (other vascular procedure with major complication/comorbidity, with complication/comorbidity, and without complication/comorbidity, respectively). Additional clinical data were incorporated from the Vascular Quality Initiative clinical registry. For non-Medicare patients, reimbursement was indexed to Medicare rates. Contribution margins (reimbursement minus cost) from technical and professional services were analyzed for each patient and summarized by DRG. We compared technical, professional, and total costs; reimbursement; and contribution margins across DRGs using univariate statistics and evaluated factors associated with total contribution margin using median quantile regression. RESULTS: We analyzed 68 patients with hemodynamically confirmed CLI (46% rest pain, 54% tissue loss), of whom 25% received a prosthetic graft. Mean age was 66.1 ± 11.6 years, 69% were male, 49% diabetic, 44% current smokers, and 4% on dialysis. In general, total infrainguinal bypass cost was adequately compensated for patients assigned only the most complex DRG 252 (median, $2490; interquartile range [IQR], -$1,621 to $10,080). In the majority of patients with less complex DRG 253 (median, -$3,100; IQR, -$8499 to $109) and DRG 254 (median, -$4902; IQR, -$9259 to $1059), reimbursement did not cover the cost of care. Both technical costs and professional costs varied significantly with the complexity of DRG. Although reimbursement from technical services increased alongside increasing complexity of DRG, there was insignificant variation in professional reimbursement as DRG complexity increased. On multivariable modeling, longer length of stay (-$2547 per additional day) and preoperative dialysis (-$5555) were significantly associated with negative margins. CONCLUSIONS: For the majority of patients with CLI, current Medicare reimbursement does not adequately cover the cost of providing care after open bypass surgery. As commercial insurers move toward Medicare reimbursement rates, more granular risk stratification profiles are needed to ensure open surgical care for patients with CLI remains financially sustainable.

Contemporary Treatment of Popliteal Artery Aneurysms in 14 Countries: A Vascunet Report.

OBJECTIVE: Popliteal artery aneurysm (PAA) is the second most common arterial aneurysm. Vascunet is an international collaboration of vascular registries. The aim was to study treatment and outcomes. METHODS: This was a retrospective analysis of prospectively registered population based data. Fourteen countries contributed data (Australia, Denmark, Finland, France, Hungary, Iceland, Italy, Malta, New Zealand, Norway, Portugal, Serbia, Sweden, and Switzerland). RESULTS: During 2012-2018, data from 10 764 PAA repairs were included. Mean values with between countries ranges in parenthesis are given. The incidence was 10.4 cases/million inhabitants/year (2.4-19.3). The mean age was 71.3 years (66.8-75.3). Most patients, 93.3%, were men and 40.0% were active smokers. The operations were elective in 73.2% (60.0%-85.7%). The mean pre-operative PAA diameter was 32.1 mm (27.3-38.3 mm). Open surgery dominated in both elective (79.5%) and acute (83.2%) cases. A medial surgical approach was used in 77.7%, and posterior in 22.3%. Vein grafts were used in 63.8%. Of the emergency procedures, 91% (n = 2 169, 20.2% of all) were for acute thrombosis and 9% for rupture (n = 236, 2.2% of all). Thrombosis patients had larger aneurysms, mean diameter 35.5 mm, and 46.3% were active smokers. Early amputation and death were higher after acute presentation than after elective surgery (5.0% vs. 0.7%; 1.9% vs. 0.5%). This pattern remained one year after surgery (8.5% vs. 1.0%; 6.1% vs. 1.4%). Elective open compared with endovascular surgery had similar one year amputation rates (1.2% vs. 0.2%; p = .095) but superior patency (84.0% vs. 78.4%; p = .005). Veins had higher patency and lower amputation rates, at one year compared with synthetic grafts (86.8% vs. 72.3%; 1.8% vs. 5.2%; both p < .001). The posterior open approach had a lower amputation rate (0.0% vs. 1.6%, p = .009) than the medial approach. CONCLUSION: Patients presenting with acute ischaemia had high risk of amputation. The frequent use of endovascular repair and prosthetic grafts should be reconsidered based on these results.

Computed Tomography Angiography in the Assessment of Great Saphenous Vein as Conduit for Infrainguinal Bypass Surgery.

INTRODUCTION: The great saphenous vein (GSV) is commonly used as a conduit during infrainguinal bypass (IIB) and is usually well seen on computed tomography angiography (CTA) which is frequently performed for preoperative planning. In this study, we asked whether CTA could replace ultrasonography (US) as the primary mode of conduit assessment, by comparing GSV measurements for patients who underwent both CTA and US vein mapping prior to IIB. METHODS: All IIB that were completed in the six-and-a-half-year period from January 1, 2012, to July 31, 2018, at the authors' institution were examined. Great saphenous vein measurements were analyzed for patients who had undergone both CTA and US vein mapping. Correlation between the measurements was calculated with the Pearson correlation coefficient. Data were then examined using Bland-Altman plots. Then categorical analysis was used to determine the adequacy of GSV for use as a bypass conduit. RESULTS: There were 302 patients who underwent IIB, with 73 legs, in 47 patients, examined with CTA and US. Computed tomography angiography and US measurements were moderately correlated (r = 0.531) across all measurement locations. Correlation progressively reduced distally (proximal thigh r = 0.534, midthigh r = 0.536, knee r = 0.35, midcalf r = 0.185, P = .074, ankle r = 0.078, P = .485). Bland-Altman plots of the pooled location data demonstrated no systematic bias. However, the upper and lower limits of agreement were wide, between -2.02 and +2.37 mm, demonstrating a lack of agreement between CTA and US. Analysis of each location revealed similar findings. A receiver operator characteristic curve was constructed based on a minimum US GSV diameter for adequate bypass conduit of 3 mm. The CTA value that maximized the Youden index was 3.8 mm. CONCLUSION: The level of error between CTA and US measurements, demonstrated by the large limits of agreement on Bland-Altman plots, would not be clinically acceptable. However, if a larger threshold is accepted, CTA has the potential to replace preoperative US vein mapping of GSV.

Endovascular Versus Surgical Revascularization for Acute Limb Ischemia: A Propensity-Score Matched Analysis.

BACKGROUND: The optimal revascularization strategy for acute limb ischemia (ALI) remains unclear, and contemporary comparative effectiveness data on endovascular versus surgical revascularization are lacking. METHODS: We used the 2010 to 2014 National Inpatient Sample databases to identify hospitalizations with a primary diagnosis of ALI. Patients were propensity-score matched on the likelihood of undergoing endovascular versus surgical revascularization using a logistic regression model. The primary outcome was in-hospital mortality. Secondary outcomes included myocardial infarction, stroke, composite of death/myocardial infarction/stroke, any amputation, fasciotomy, acute kidney injury, major bleeding, transfusion, vascular complications, length of stay, and hospital costs. RESULTS: Of 10 484 (weighted national estimate=51 914) hospitalizations for ALI, endovascular revascularization was performed in 5008 (47.8%) and surgical revascularization in 5476 (52.2%). In the propensity-score matched cohort (n=7746; 3873 per group), patients who underwent endovascular revascularization had significantly lower in-hospital mortality (2.8% versus 4.0%; P=0.002), myocardial infarction (1.9% versus 2.7%; P=0.022), composite of death/myocardial infarction/stroke (5.2% versus 7.5%; P<0.001), acute kidney injury (10.5% versus 11.9%; P=0.043), fasciotomy (1.9% versus 8.9%; P<0.001), major bleeding (16.7% versus 21.0%; P<0.001), and transfusion (10.3% versus 18.5%; P<0.001), but higher vascular complications (1.4% versus 0.7%; P=0.002), compared with those undergoing surgical revascularization. Rates of any amputation were similar between the 2 groups (4.7% versus 5.1%; P=0.43). Median length of stay was shorter and hospital costs higher with endovascular versus surgical revascularization. CONCLUSIONS: In patients with ALI, endovascular revascularization was associated with better in-hospital clinical outcomes compared with surgical revascularization. Contemporary randomized controlled trials are needed to determine the optimal revascularization strategy for ALI.

Economic burden and clinical impact of preoperative opioid dependence for patients undergoing lower extremity bypass surgery.

OBJECTIVE: Surgeons' prescription practices and the opioid epidemic have received significant attention in the media. Limited data exist, however, on the impact of prior or coexistent opioid use on vascular surgery outcomes. This study aimed to quantify the incidence, economic burden, and clinical impact of pre-existing opioid dependency in patients undergoing lower extremity bypass (LEB) surgery. METHODS: Data were collected from 1,132,645 weighted (230,858 unweighted) patient admissions for LEB in the National Inpatient Sample for the years 2002 to 2015. Patients with a concomitant diagnosis of opioid abuse or dependency were identified using International Classification of Diseases, Ninth Revision codes. Matched cohorts of patients with (n = 606 unweighted) and without (n = 32,343 unweighted) opioid dependence were created using coarsened exact matching to control for patient demographics. Linear regression was used to control for hospital-level factors and to identify differential outcomes for patients with opioid dependency. Our primary end points were hospital cost and length of stay. Our secondary end points were surgical complications and in-hospital mortality. RESULTS: There were 1,132,645 (230,858 unweighted) patient admissions for LEB in the National Inpatient Sample during 2002 to 2015. There were 3190 (0.3%) patients (643 unweighted) who had a diagnosis of pre-existing opioid dependency. The incidence of opioid dependency rose over time (2002, 0.13%; 2015, 0.63%; R2 = 0.90; P < .001). Before matching, opioid-dependent patients were younger (53.9 ± 12.3 years vs 66.7 ± 12.1 years; P < .001) and more likely to be male (65.2% vs 61.9%; P < .001), to be nonwhite (37.9% vs 24.1%; P < .001), to pay with Medicaid (29.6% vs 7.4%; P < .001), and to fall in the lowest income quartile based on ZIP code (39.6% vs 27.5%; P < .001). After matching, opioid-dependent patients (n = 606 unweighted vs n = 32,343 unweighted nonopioid-dependent patients) were at increased risk of surgical site infections (odds ratio [OR], 1.61; P = .006), major bleeding (OR, 1.56; P = .04), acute kidney injury (OR, 1.46; P = .02), and deep venous thrombosis (OR, 2.53; P = .005). Linear regression of matched cohorts revealed that opioid-dependent patients had an increased length of hospital stay (11.76 days vs 9.80 days; P < .001) and an increased mean inflation-adjusted in-hospital cost of U.S. $7032 ($37,522 vs $30,490; P < .001). CONCLUSIONS: The incidence of pre-existing opioid dependency in patients undergoing LEB continues to rise. Patients with opioid use disorder undergoing LEB surgery have substantial increases in length of hospital stay and costs. These findings highlight the importance of early preoperative recognition of this disorder in vascular surgery patients and open the opportunity for early intervention in that cohort.

Editor's Choice - Sex Related Differences in Peri-operative Mortality after Elective Repair of an Asymptomatic Abdominal Aortic Aneurysm in the Netherlands: a Retrospective Analysis of 2013 to 2018.

OBJECTIVE: The aim was to compare peri-operative (30 day and/or in hospital) mortality between women and men in the Netherlands after elective repair of an asymptomatic abdominal aortic aneurysm (AAA). METHODS: This was a retrospective study using data from the Dutch Surgical Aneurysm Audit (DSAA), a mandatory nationwide registry of patients undergoing AAA repair in the Netherlands. Patients who underwent elective open surgical (OSR) or endovascular aneurysm repair (EVAR) of an asymptomatic abdominal aortic aneurysm (AAA) between 2013 and 2018 were included. Absolute risk differences (ARDs) with 95% confidence intervals (CIs) in peri-operative mortality between women and men were estimated. Logistic regression analyses were performed to estimate adjusted odds ratios (ORs) for mortality. Confounders included pre-operative cardiac and pulmonary comorbidity, serum haemoglobin, serum creatinine, type of AAA repair, and AAA diameter. RESULTS: Some 1662 women and 9637 men were included, of whom 507 (30.5%) women and 2056 (21.3%) men underwent OSR (p < .001). Crude peri-operative mortality was 3.01% in women and 1.60% in men (ARD = 1.41%, 95% CI 0.64-2.37). This significant difference was also observed for OSR (ARD = 2.63%, 95% CI 0.43-5.36), but not for EVAR (ARD = 0.36%, 95% CI -0.16 to 1.17). Female sex remained associated with peri-operative mortality after adjusting for confounders (OR = 1.79, 95% CI 1.20-2.65, p = .004), which was similarly observed for OSR (OR = 1.85, 95% CI 1.16-2.94, p = .01), but not for EVAR (OR = 1.46, 95% CI 0.72-2.95, p = .29). CONCLUSIONS: Peri-operative mortality after elective repair of an asymptomatic AAA in the Netherlands is higher in women than in men. This disparity might be explained by the higher peri-operative mortality in women undergoing OSR, because no such difference was found in patients undergoing EVAR. Yet, it is likely that there are unaccounted factors at play since female sex remained significantly associated with mortality after adjusting for type of repair.

Propensity Score-Adjusted Comparison of Long-Term Outcomes Among Revascularization Strategies for Critical Limb Ischemia.

BACKGROUND: Few studies have compared long-term outcomes among specific treatment modalities for critical limb ischemia. The aim of this study was to compare long-term outcomes with percutaneous transluminal angioplasty (PTA), stent placement, atherectomy, or surgical bypass in patients diagnosed with critical limb ischemia. METHODS: In this observational study using Medicare claims data, we identified incident cases with a primary critical limb ischemia diagnosis who received PTA, stent placement, atherectomy, or surgical bypass. We used propensity score weighting to determine the association of treatment type with all-cause mortality and major (above ankle) amputation over 4 years follow-up. RESULTS: Among 36 860 patients (10 904 PTA; 11 295 stent placement; 4422 atherectomy; 10 239 surgical bypass), all-cause mortality over 4 years was 49.3% with atherectomy, 51.4% with surgical bypass, 53.7% with stent placement, and 54.7% with PTA (P<0.05 for all pairwise comparisons). Major amputation rates over 4 years were 6.8% with atherectomy, 7.8% with stent placement, 8.1% with PTA, and 10.8% with surgical bypass (P<0.05 for all pairwise comparison except PTA versus stent). CONCLUSIONS: Among Medicare beneficiaries who received PTA, stent placement, atherectomy, or surgical bypass for critical limb ischemia, high mortality and major amputation rates were observed with minor differences among treatment groups. Statistically significant group differences of uncertain clinical importance were observed for several comparisons. Results from observational research may be susceptible to bias because of unmeasured confounders and, therefore, these comparative results should be interpreted with caution.

Elective infrainguinal lower extremity bypass for claudication is associated with high postoperative intensive care utilization.

BACKGROUND: The overall use of intensive care units (ICUs) in the United States has been steadily increasing and is associated with tremendous health care costs. We suspect that the burden of ICU utilization after elective infrainguinal lower extremity bypass (LEB) procedures is high, despite relatively low risks of complications in the immediate postoperative period. We sought to identify the burden of ICU utilization after elective LEB in patients with claudication. METHODS: We queried the Premier Healthcare Database for all adult patients undergoing first recorded elective infrainguinal LEB for claudication from 2009 to 2015. Baseline characteristics and ICU utilization on postoperative day 0 (POD 0) were identified for each patient using Premier room and board chargemaster codes. A bivariate logistic regression was performed and postestimation concordance statistics were calculated to identify predictors of postoperative ICU vs regular surgical floor admission immediately after surgery. RESULTS: There were 6010 patients who met the selection criteria, of whom 2772 (46.1%) were admitted to the ICU and 3238 (53.9%) to the regular surgical floor on POD 0. Whereas patient-level factors were responsible for minor differences found in postoperative admission to the ICU after elective LEB, hospital characteristics made up the majority of variation in admission practices. Specifically, patients undergoing elective infrainguinal LEB in rural, nonteaching, small hospitals and those in certain geographic regions were more likely to be admitted to the ICU than to the floor (all, P < .001). Patient-level factors were poorly predictive of admission to the ICU immediately postoperatively, with C statistics ranging from 0.50 to 0.53. In contrast, hospital-level factors had higher C statistics ranging from 0.51 to 0.66, with geographic location being the strongest predictor of post-LEB ICU admission. There were no significant differences in the incidence of postoperative wound complications, major adverse limb events, major adverse cardiac events, or in-hospital mortality between groups (all, P ≥ .32). The median total hospital cost was $2340 higher for ICU compared with floor admission ($13,273 [interquartile range, $10,136-$17,883] vs $10,927 [interquartile range, $8342-$14,523]; P < .001). CONCLUSIONS: Nearly half of patients are admitted to an ICU directly after elective infrainguinal LEB for claudication. This practice is associated with significantly higher hospital cost and is predominantly influenced by hospital-level rather than by patient-level factors. Perioperative morbidity and mortality were similar regardless of postoperative disposition. To minimize ICU utilization, postoperative care intensity should be determined by clinical severity of the patient rather than by hospital routine.

Socioeconomic Distressed Communities Index associated with worse limb-related outcomes after infrainguinal bypass.

OBJECTIVE: Several studies have demonstrated that socioeconomic factors may affect surgical outcomes. Analyses in vascular surgery have been limited by the availability of individual or community-level socioeconomic data. We sought to determine whether the Distressed Communities Index (DCI), a composite socioeconomic ranking by ZIP code, could predict short- and long-term outcomes for patients with peripheral artery disease. METHODS: All Virginia Quality Initiative patients (n = 2578) undergoing infrainguinal bypass (2011-2017) within a region of 17 centers were assigned a composite DCI score. The score was developed by the Economic Innovation Group and is normally distributed from 0 (no distress) to 100 (severe distress) based on measures of community unemployment, education level, poverty rate, median income, business growth, and housing vacancies. Severely distressed communities were defined as the top quartile DCI (>75). Hierarchical regression assessed short-term outcomes, and time-to-event analyses assessed long-term results. RESULTS: Infrainguinal bypass patients in this study came from disproportionately distressed communities, with 29% of patients living within the highest distress DCI quartile (P < .0001), with high variability by hospital (DCI range, 12-67). These patients from severely distressed areas were younger, more likely to smoke, and disproportionately African American and had higher rates of medical comorbidities (all P < .05). Whereas patients from severely distressed communities had an equivalent rate of 30-day major adverse cardiac and cerebrovascular events (5% vs 4%; P = .86), they had increased rates of major adverse limb events (MALEs) at 13% vs 10% (P = .03). This trend persisted in the long term, with higher 1-year estimates of MALEs (21% vs 17%; P = .01) as well as the components of amputation (17% vs 12%; P = .006) and thrombectomy (11% vs 6%; P = .002). Patients with high socioeconomic distress also had higher rates of occlusion (17% vs 11%; P = .003). CONCLUSIONS: In this study, patients from severely distressed communities were found to have increased rates of MALEs, an association that persisted long term. Mitigating risk associated with socioeconomic determinants of health has the potential to improve outcomes for patients with peripheral artery disease.

Frailty assessment in older adults undergoing interventions for peripheral arterial disease.

OBJECTIVE: Frailty is a multidimensional syndrome that influences postoperative morbidity and mortality after vascular procedures; however, its integration in clinical practice has been limited, given the lack of consensus on how to measure it. This study sought to compare the incremental predictive value of six different nonphysical performance frailty scales to predict poor outcomes after interventions for peripheral arterial disease (PAD). METHODS: This preplanned analysis of the FRailty Assessment In Lower Extremity arterial Disease (FRAILED) prospective cohort included two centers recruiting patients between July 1, 2015, and October 1, 2016. Individuals who underwent vascular interventions for Rutherford class 3 or higher PAD were enrolled. The following scales were compared: Edmonton Frail Scale, Groningen Frailty Indicator (GFI), modified Essential Frailty Toolset (mEFT), modified Frailty Index, Multidimensional Prognostic Index, and the Risk Analysis Index-C. The primary end point was a composite of all-cause mortality and major disability at 12 months after the procedure. The secondary end point was length of stay. Logistic regression was used to determine the association of frailty with the primary end point after adjusting for confounders. To compare the incremental predictive value of each frailty scale, model performance statistics were calculated. RESULTS: The cohort was composed of 148 patients with a mean age of 70 years. Depending on the scale used, the prevalence of frailty ranged from 16% to 70%. Frailty as measured by the GFI (adjusted odds ratio, 1.76; 95% confidence interval, 1.14-2.72) and mEFT (adjusted odds ratio, 2.71; 95% confidence interval, 1.29-5.73) predicted mortality and worsening disability at 12 months after interventions for PAD. Furthermore, there was statistically significant C-statistic, Bayesian information criterion, and integrated discrimination improvement when the GFI and mEFT were added to the baseline model. Frailty was not associated with length of stay. CONCLUSIONS: Frailty is associated with mortality and worsening disability after interventions for PAD. The GFI and mEFT performed well and identified vulnerable older adults who are at risk of poor outcomes after interventions for PAD and recommended for use in this setting.

Two-Year Outcomes of Early Cannulation Arteriovenous Grafts for End-Stage Renal Disease.

BACKGROUND: Almost 80% of patients with end-stage renal disease (ESRD) initiate dialysis via a central venous catheter (CVC). CVCs are associated with multiple complications and a high cost of care. The purpose of our project is to determine the impact of early cannulation arteriovenous grafts (ECAVGs) on quality of care and costs. METHODS: The dialysis access modality, complications, secondary interventions, hospital outcomes, and detailed costs were tracked for 397 sequential patients who underwent access creation between July 2014 and October 2018. Complications were grouped into deep vein thrombosis, line infections, sepsis, pneumothorax, and other. Secondary interventions included angioplasty, angioplasty and stent grafting, thrombectomy, surgical revision, and explantation. Hospital outcomes included length of stay, inpatient mortality, 30-day readmission, and discharge disposition. Costs included supplies, medications, laboratory tests, labor, and other direct costs. All variables were measured at the time of the index procedure, 30 days, 90 days, 180 days, 270 days, 1 year, 18 months, and 2 years. RESULTS: There were 131 patients who underwent arteriovenous fistula (AVF) and 266 who received ECAVG for dialysis access. The total cost of care per patient was $17,523 for AVF and $5,894 for ECAVG at 1 year (P < 0.01). Primary-assisted patency for AVF was 49.3% versus 81.4% for ECAVG (P = 0.027), and secondary-assisted patency for AVF was 63.8% versus 85.4% for ECAVG at 1 year (P = 0.011). There was a survival advantage for ECAVGs at 1 year (78.6% for AVF vs 85.0% for ECAVG, P = 0.034). Patients who received ECAVG had fewer CVC days (2.3% vs 19.1% for AVF, P < 0.001), fewer complications (1.6% vs. 21.5% for AVF, P < 0.001), and fewer secondary interventions (17.0% vs 52.5% for AVF, P < 0.001). CONCLUSIONS: This is the first study on patients with ESRD to report detailed outcomes and cost analysis as it relates to AVF versus ECAVG. ECAVGs have an advantage over AVFs due to lower overall cost and better clinical outcomes at 1 year. Implementation of an urgent start dialysis access program centered around ECAVGs may help achieve the national goal of better health care at a lower cost for patients with ESRD.