Association of Pre and Perioperative Vein Mapping with Hemodialysis Access Characteristics and Outcomes.

BACKGROUND: We investigated the utility of both pre and perioperative vein mapping for evaluating vessel suitability for both arteriovenous fistula (AVF) and arteriovenous graft (AVG) creation. In our practice, we used both mapping methods to detect arterial issues and to maximize AVF creation. We hypothesized that the patients whose operative plan changed based on their perioperative mapping would ultimately benefit from more optimal access placement with maintained rates of maturation and functional patency. METHODS: We performed a retrospective chart review evaluating patients who received initial hemodialysis (HD) access from January 1, 2017, to December 31, 2021, at the Veterans Affairs (VA) Puget Sound in Seattle, Washington. Patients were separated by whether their final procedure was congruent with the best access predicted from the preoperative vein mapping or noncongruent. The primary outcome was fistula maturation. Secondary outcomes were functional patency and number of procedures required to achieve maturation or to maintain functional patency. Results were analyzed using Pearson's chi-squared, Moods median, Student's t-tests, and Kaplan-Meier curves. RESULTS: Preoperative vein mapping uncovered arterial issues in 42% of the patient population. Initial HD access was created in 130 patients (n = 69 congruent, n = 61 noncongruent). Perioperative ultrasound led to a change in the created access in 47% of patients. Within the noncongruent group, 74% received access creation at a more anatomically favorable site compared to their predicted access, 47% were changed to forearm fistula, 20% to brachiocephalic (BC) from previously planned brachiobasilic (BB) or graft, and 7% to BB from previously planned graft. Maturation rates were similar in both groups (congruent 86% and noncongruent 82%), and there were no significant differences in the duration of functional patency or the number of procedures needed to achieve maturation or maintain functional patency. CONCLUSIONS: Utilization of pre and perioperative ultrasound for all patients resulted in higher rates of native AVF, forearm placement, and one-stage operations, with maintained maturation rates and functional patency in patients who were otherwise unsuitable candidates based on preoperative vein mapping alone.

Effect of a Decision Aid on Agreement Between Patient Preferences and Repair Type for Abdominal Aortic Aneurysm: A Randomized Clinical Trial.

Importance: Patients with abdominal aortic aneurysm (AAA) can choose open repair or endovascular repair (EVAR). While EVAR is less invasive, it requires lifelong surveillance and more frequent aneurysm-related reinterventions than open repair. A decision aid may help patients receive their preferred type of AAA repair. Objective: To determine the effect of a decision aid on agreement between patient preference for AAA repair type and the repair type they receive. Design, Setting, and Participants: In this cluster randomized trial, 235 patients were randomized at 22 VA vascular surgery clinics. All patients had AAAs greater than 5.0 cm in diameter and were candidates for both open repair and EVAR. Data were collected from August 2017 to December 2020, and data were analyzed from December 2020 to June 2021. Interventions: Presurgical consultation using a decision aid vs usual care. Main Outcomes and Measures: The primary outcome was the proportion of patients who had agreement between their preference and their repair type, measured using χ2 analyses, κ statistics, and adjusted odds ratios. Results: Of 235 included patients, 234 (99.6%) were male, and the mean (SD) age was 73 (5.9) years. A total of 126 patients were enrolled in the decision aid group, and 109 were enrolled in the control group. Within 2 years after enrollment, 192 (81.7%) underwent repair. Patients were similar between the decision aid and control groups by age, sex, aneurysm size, iliac artery involvement, and Charlson Comorbidity Index score. Patients preferred EVAR over open repair in both groups (96 of 122 [79%] in the decision aid group; 81 of 106 [76%] in the control group; P = .60). Patients in the decision aid group were more likely to receive their preferred repair type than patients in the control group (95% agreement [93 of 98] vs 86% agreement [81 of 94]; P = .03), and κ statistics were higher in the decision aid group (κ = 0.78; 95% CI, 0.60-0.95) compared with the control group (κ = 0.53; 95% CI, 0.32-0.74). Adjusted models confirmed this association (odds ratio of agreement in the decision aid group relative to control group, 2.93; 95% CI, 1.10-7.70). Conclusions and Relevance: Patients exposed to a decision aid were more likely to receive their preferred AAA repair type, suggesting that decision aids can help better align patient preferences and treatments in major cardiovascular procedures. Trial Registration: ClinicalTrials.gov Identifier: NCT03115346.

Patient information sources when facing repair of abdominal aortic aneurysm.

OBJECTIVE: Shared medical decision making is most important when there are competing options for repair such as in treatment of abdominal aortic aneurysm (AAA). We sought to understand the sources of patients' pre-existing knowledge about AAA to better inform treating physicians about patients' needs for preoperative counseling. METHODS: We performed a multicenter survey of patients facing AAA repair at 20 Veterans Affairs hospitals across the United States as part of the Preferences for Open Versus Endovascular Repair of AAA study. A validated survey instrument was administered to examine the sources of information available and commonly used by patients to learn about their repair options. The survey was administered by study personnel before the patient had any interaction with the vascular surgeon because survey data were collected before the vascular clinic visit. RESULTS: Preliminary analysis of data from 99 patients showed that our cohort was primarily male (99%) and elderly (mean age 73 years). Patients commonly had a history of hypertension (86%), prior myocardial infarction (32%), diabetes (32%), and were overweight (58%). Patients arrived at their surgeon's office appointment with limited information. A majority of patients (52%) reported that they had not talked to their primary care physician at all about their options for AAA repair, and one-half (50%) reported that their view of the different surgical options had not been influenced by anyone. Slightly less than one-half of patients reported that they did not receive any information about open surgical aneurysm repair and endovascular aortic aneurysm repair (41% and 37%, respectively). Few patients indicated using the internet as their main source of information about open surgical aneurysm repair and endovascular aortic aneurysm repair (10% and 11%, respectively). CONCLUSIONS: Patients are commonly referred for AAA repair having little to no information regarding AAA pathology or repair options. Fewer than one in five patients searched the internet or had accessed other sources of information on their own. Most vascular surgeons should assume that patients will present to their first vascular surgery appointment with minimal understanding of the treatment options available to them.

Integrated residency is associated with an increase in women among vascular surgery trainees.

BACKGROUND: During the past decade, the proportion of women within graduate medical education has increased. Correspondingly, the proportion of women in almost every specialty has increased, including surgical specialties. We sought to evaluate the effect of establishing vascular surgery integrated residencies (VSIRs) on the proportion of women in vascular surgery training programs. METHODS: Resident data were obtained from the Accreditation Council for Graduate Medical Education (ACGME) Data Resource Book for the academic years 2007 to 2016. Data were collected on overall ACGME residency numbers as well as on the following surgical subspecialties: vascular, general, thoracic, neurologic, orthopedic, otolaryngologic, and urologic surgery. The number and proportion of women per year in VSIRs and vascular surgery fellowships were compared with those in the other surgical specialties. RESULTS: During the study period, the proportion of women in ACGME-accredited residency programs increased from 0.41 (n = 43,695/107,851) to 0.44 (n = 57,130/129,720) of residents. Since the advent of the VSIR, the number of trainees within vascular surgery has increased by 56% from 221 to 501 trainees. The proportion of women in vascular surgery training programs has increased from 0.12 (n = 27/221) to 0.33 (n = 164/501) of trainees. This increase during the 9-year study period was greater than in any other surgical subspecialty and greatest within the VSIR. Compared with fellowship training programs, integrated surgical training programs within the same subspecialty had a higher proportion of women, although variability between surgical subspecialties remained notable. CONCLUSIONS: Although it is lower than the proportion of women within all graduate medical education training programs, an increasing proportion of women have entered vascular surgery training during the study period. This appears to be related to the introduction of VSIRs and exceeds the proportion of women entering almost all other surgical subspecialties at a rate of change faster than in all other surgical subspecialties. Further work to understand surgical specialty preferences and choice of careers after training is warranted.

Outcome Comparison of TEVAR with and without Left Subclavian Artery Revascularization from Analysis of Nationwide Inpatient Sample Database.

BACKGROUND: The purpose of this study was to compare the outcomes of thoracic endovascular aortic repair (TEVAR) without and with left subclavian artery (LSA) revascularization using the Nationwide Inpatient Sample (NIS) database. METHODS: NIS records from 2005 to 2013 were retrospectively analyzed to identify patients undergoing TEVAR without and with LSA revascularization. Perioperative outcomes were compared between the two groups. The LSA revascularization group was further subdivided to compare perioperative outcomes if the revascularization was performed pre- or post-TEVAR or if the revascularization was performed open versus endovascular. Comparisons were examined using univariable analysis and multivariable logistic regression. Multivariable models were constructed using a forward selection approach with P < 0.05 required for model entry. Odds ratios are expressed per standard deviation change for continuous covariates. Continuous variables were compared between different groups using t-test, and categorical variables were compared using the chi-squared test. All statistical analyses were performed using R (cran.r-project.org). RESULTS: 7,773 TEVAR patients were included in this study. 6,411 (82.5%) were performed without and 1,362 (17.5%) with LSA revascularization. The rate of revascularization for LSA coverage during TEVAR doubled after the Society for Vascular Surgery Guidelines recommending revascularization were published in 2009. Groups were not significantly different in age (65.5 ± 15.8 and 66.1 ± 14.4 years old, respectively), gender, or race. Multivariable analysis showed that although rates of spinal cord ischemia and upper extremity ischemia were similar, perioperative cardiac complications (OR 1.5, 95% CI [1.2, 1.9], P = 0.025), stroke (OR 2.1, 95% CI [1.6, 2.8], P = 0.001), and pulmonary complications (OR 1.9, 95% CI [1.7, 2.3], P < 0.001) were significantly higher in the patients undergoing TEVAR with LSA revascularization than those without. Of the 1,362 patients with LSA revascularization, 1,251 (91.9%) were performed pre-TEVAR and 111 (8.1%) were performed post-TEVAR. Among the 1,251 patients with pre-TEVAR LSA revascularization, 583 had open surgery and 553 had stenting. In 115 patients, LSA revascularization was coded as both open and endovascular. Compared with pre-TEVAR revascularization, post-TEVAR revascularization was associated with higher risks of pulmonary complications and spinal cord ischemia. Endovascular LSA revascularization had lower pulmonary and stroke morbidity versus open LSA revascularization. The perioperative outcomes for the LSA revascularization subgroups are summarized. CONCLUSIONS: TEVAR with LSA revascularization is associated with significantly increased rates of perioperative stroke and cardiopulmonary complications. LSA revascularization before TEVAR, compared with post-TEVAR revascularization, had lower perioperative complications. In high-risk patients, endovascular LSA revascularization may be recommended over open surgery.

Anti-phosphorylcholine IgM, an Anti-inflammatory Mediator, Predicts Peripheral Vein Graft Failure: A Prospective Observational Study.

OBJECTIVES: One third of infrainguinal vein bypasses may fail within the first 1.5 years. Pro- and anti-inflammatory mechanisms are thought to be involved in these graft stenoses and occlusions. In previous studies, low levels of anti-phosphorylcholine IgM (anti-PC IgM, an innate anti-inflammatory IgM) have been associated with increased cardiovascular events. In this study, the peri-operative dynamics of anti-PC IgM levels were established during leg bypass surgery, and associations assessed between anti-PC IgM levels and primary graft patency. DESIGN AND METHODS: This was a prospective, observational cohort study of infrainguinal autogenous vein bypass for peripheral arterial occlusive disease involving four university affiliated hospitals. Plasma cytokine and anti-PC IgM levels were measured pre- and post-operatively. The outcome of interest was loss of primary graft patency because of occlusion or intervention for graft stenosis. RESULTS: One hundred and forty-two consecutive patients were enrolled: mean age 66 (46-91); 91% white race and male; 72.5% critical limb ischaemia (Fontaine III or IV). Median pre-operative anti-PC IgM levels were 49 units/mL (IQR 32.3-107.7, mean 89.8 + 101 sd). During follow up of an average of 1.8 years (1 month-7.4 years), 50 (35.2%) grafts lost primary patency. Pre-operative levels of interleukin 6 or C-reactive protein did not predict graft failure. Patients with pre-operative anti-PC IgM values in the lowest quartile had a twofold increased risk of graft failure (multivariable Cox proportional hazard, p = .03, HR 2.11, 95% CI 1.09-4.07), even after accounting for the other significant factors of conduit diameter, distal anastomosis, smoking, and the severity of leg ischaemia. CONCLUSIONS: Low levels of anti-PC IgM are associated with vein bypass graft failure. This biological mediator may be a useful marker to identify patients at higher risk, and offers the potential for novel, directed therapies for vascular inflammation and its consequences.

Comparison of outcomes in women and men following carotid interventions in the Washington state's Vascular Interventional Surgical Care and Outcomes Assessment Program.

BACKGROUND: The benefit for carotid endarterectomy (CEA) to prevent a potential stroke has been shown to be less beneficial for women compared with men and the risk of carotid stenting (CAS) is higher in women than men. We hypothesized that a community-based Washington state registry data would also reveal increased morbidity and mortality for women undergoing carotid interventions. METHODS: Deidentified data for CEA and CAS between 2010 and 2015 were obtained from 19 hospitals participating in the Washington State Vascular-Interventional Surgical Care and Outcomes Assessment Program. Data analysis compared in-hospital composite outcome of stroke and mortality from CEA and CAS between women and men. RESULTS: Over the study period, 3704 individuals underwent CEA (n = 2759; 49.5% symptomatic) and CAS (n = 945; 60.9% symptomatic). Women accounted for 39.5% of the cohort. Women were slightly younger than men (70.0 ± 10.2 vs 71.0 ± 9.6 years respectively; P < .01), less likely to be smokers (70.1% vs 75.6%; P < .01), and less likely to have a diagnosis of coronary artery disease (32.9% vs 46.5%; P < .01). Fewer women underwent CEA for symptomatic carotid disease (46.1% vs 51.8%; P < .01). There were no statistically significant differences in the postoperative in-hospital stroke and mortality among women and men undergoing CEA (asymptomatic, 0.8% vs 1.4% [P = .36]; symptomatic, 1.8% vs 2.2% [P = .58]) and CAS (asymptomatic, 1.4% vs 2.2% [P = .56]; symptomatic, 4.6% vs 2.5% [P = .18]). Hospital duration of stay and discharge disposition were similar for women and men. A subanalysis of the octogenarian cohort undergoing CAS demonstrated a substantial increase in-hospital stroke and mortality among women and men (11.6% [CAS] vs 2.2% [CEA]; P = .024). CONCLUSIONS: In the Washington state Vascular-Interventional Surgical Care and Outcomes Assessment Program registry, hospital composite outcome of stroke and mortality following carotid interventions from 2010 to 2015 were noted to be similar for women and men. The notable exception to this finding was observed in subcohort of women undergoing CAS for symptomatic carotid disease at age 80 years or older. These findings should be taken into account when risk stratifying patients for carotid interventions.

Clinical factors that influence the cellular responses of saphenous veins used for arterial bypass.

OBJECTIVE: When an autogenous vein is harvested and used for arterial bypass, it suffers physical and biologic injuries that may set in motion the cellular processes that lead to wall thickening, fibrosis, stenosis, and ultimately graft failure. Whereas the injurious effects of surgical preparation of the vein conduit have been extensively studied, little is known about the influence of the clinical environment of the donor leg from which the vein is obtained. METHODS: We studied the cellular responses of fresh saphenous vein samples obtained before implantation in 46 patients undergoing elective lower extremity bypass surgery. Using an ex vivo model of response to injury, we quantified the outgrowth of cells from explants of the adventitial and medial layers of the vein. We correlated this cellular outgrowth with the clinical characteristics of the patients, including the Wound, Ischemia, and foot Infection classification of the donor leg for ischemia, wounds, and infection as well as smoking and diabetes. RESULTS: Cellular outgrowth was significantly faster and more robust from the adventitial layer than from the medial layer. The factors of leg ischemia (P < .001), smoking (P = .042), and leg infection (P = .045) were associated with impaired overall outgrowth from the adventitial tissue on multivariable analysis. Only ischemia (P = .046) was associated with impaired outgrowth of smooth muscle cells (SMCs) from the medial tissue. Co-culture of adventitial cells and SMCs propagated from vein explants revealed that adventitial cells significantly inhibited the growth of SMCs, whereas SMCs promoted the growth of adventitial cells. The AA genotype of the -838C>A p27 polymorphism (previously associated with superior graft patency) enhanced these effects, whereas the factor of smoking attenuated adventitial cell inhibition of SMC growth. Comparing gene expression, the cells cultured from the media overexpress Kyoto Encyclopedia of Genes and Genomes pathways associated with inflammation and infection, whereas those from the adventitia overexpress gene families associated with development and stem/progenitor cell maintenance. CONCLUSIONS: The adverse clinical environment of the leg may influence the biologic behavior of the cells in the vein wall, especially the adventitial cells. Chronic ischemia was the most significant factor that retards adventitial cell outgrowth. The cells arising from the vein adventitia may be key players in determining a healthy adaptive or a pathologic response to the injuries associated with vein grafting.

A single nucleotide polymorphism of cyclin-dependent kinase inhibitor 1B (p27Kip1) associated with human vein graft failure affects growth of human venous adventitial cells but not smooth muscle cells.

BACKGROUND: Cyclin-dependent kinase inhibitor 1B (p27Kip1) is a cell-cycle inhibitor whose -838C>A single nucleotide polymorphism (rs36228499; hereafter called p27 SNP) has been associated with the clinical failure of peripheral vein grafts, but the functional effects of this SNP have not been demonstrated. METHODS: Human saphenous vein adventitial cells and intimal/medial smooth muscle cells (SMCs) were derived from explants obtained at the time of lower extremity bypass operations. We determined the following in adventitial cells and SMCs as a function of the p27 SNP genotype: (1) p27 promoter activity, (2) p27 messenger (m)RNA and protein levels, and (3) growth and collagen gel contraction. Deoxyribonuclease I footprinting was also performed in adventitial cells and SMCs. RESULTS: p27 promoter activity, deoxyribonuclease I footprinting, p27 mRNA levels, and p27 protein levels demonstrated that the p27 SNP is functional in adventitial cells and SMCs. Both cell types with the graft failure protective AA genotype had more p27 mRNA and protein. As predicted because of higher levels of p27 protein, adventitial cells with the AA genotype grew slower than those of the CC genotype. Unexpectedly, SMCs did not show this genotype-dependent growth response. CONCLUSIONS: These results support the functionality of the p27 SNP in venous SMCs and adventitial cells, but an effect of the SNP on cell proliferation is limited to only adventitial cells. These data point to a potential role for adventitial cells in human vein graft failure and also suggest that SMCs express factors that interfere with the activity of p27.

p27(kip1) Knockout enhances collateralization in response to hindlimb ischemia.

OBJECTIVE: The natural response to arterial occlusive disease is enlargement of collaterals; however, the molecular factors that control collateralization are not well understood. The gene p27(Kip1) (p27) affects human response to arterial injury. Previous studies have shown that overexpression of p27 inhibits vascular endothelial and vascular smooth muscle cell (VSMC) proliferation and angiogenesis. To test the hypothesis that knockout of p27 would improve collateralization in reaction to ischemia, we performed in vivo and in vitro experiments using p27 knockout (p27(-/-)) and wild-type (wt) mice. METHODS: Hindlimb ischemia was induced by left femoral artery ligation in p27(-/-) and wt (C57BL/6) female mice. The mice underwent weekly laser Doppler perfusion imaging of the footpads until sacrifice on postoperative day 28 followed by microcomputed tomography scanning of both hindlimbs. VSMCs were isolated from p27(-/-) and wt mice and used in migration and gel contraction assays in the absence and presence of the nonspecific matrix metalloproteinase (MMP) inhibitor BB94. MMP-2 and MMP-9 messenger RNA (mRNA) expression was measured by quantitative reverse transcription-polymerase chain reaction in p27(-/-) and wt VSMCs. RESULTS: p27(-/-) mice reperfused more effectively than wt mice by laser Doppler starting from day 7 (ischemic/nonischemic ratio, 0.33 ± 0.02 vs 0.25 ± 0.02; P < .05) and continuing through day 28 (0.45 ± 0.04 vs 0.31 ± 0.04; P < .05). The gracilis collateral diameter was similar for the nonischemic hindlimbs of the p27(-/-) and wt mice, and this collateral pathway increased similarly after ischemia as assessed by microcomputed tomography. However, the p27(-/-) mice significantly enlarged a novel collateral pathway that bridged directly between the femoral artery proximal to the ligation site and the saphenous or popliteal artery distal to the ligation site more than wt mice (158 ± 18.3 vs 82 ± 22 µm; P < .001). p27(-/-) VSMCs migrated more (79% ± 5% vs 56% ± 6%; P < .05) and caused more gel contraction (18% ± 5% of the initial area vs 43% ± 4%; P < .05) than wt cells. Migration and collagen contraction were abolished in p27(-/-) and wt cells by MMP inhibition. p27(-/-) cells expressed significantly more MMP-2 mRNA than wt cells did. CONCLUSIONS: Knockout of p27 enhances arterial collateralization in response to hindlimb ischemia through enlargement of a new collateral pathway. In vitro, knockout of p27 increases collagen gel contraction in addition to stimulating VSMC migration. We speculate that p27 may affect collateralization through its role in regulating MMP-2 expression.

Outcomes after stent graft therapy for dissection-related aneurysmal degeneration in the descending thoracic aorta.

OBJECTIVE: Stent graft therapy has emerged as an alternative to open surgery in the management of chronic dissection-related aneurysmal degeneration (DRAD) in the descending thoracic aorta (DTA). The incidence of perioperative complications, need for secondary aortic intervention (SAI), and rate of aneurysmal false-lumen thrombosis have not been thoroughly described. METHODS: Perioperative and midterm outcomes in patients who underwent stent graft therapy for chronic DRAD DTA at a single institution between January 2006 and September 2013 were retrospectively analyzed. Preoperative anatomic factors, including the number of visceral and renal side branches off the false lumen, and false lumen volume, were analyzed for their ability to predict treatment failure. Treatment failure was defined as death, need for a SAI, and failure to achieve thrombosis of the DRAD DTA. Treatment success was defined as thrombosis of the false lumen in the area of the DRAD DTA with stability or a decrease in the maximum diameter of the DRAD DTA. RESULTS: During the study period, 47 patients underwent stent graft therapy for chronic DRAD DTA. Patients were a mean age of 58.3 ± 11.7 years, 74.5% (n = 35) were male, and 14.9% (n = 7) had a history of connective tissue disease. The left subclavian artery was covered in 48.9% (n = 23), and revascularization was performed in 87.0% (n = 20). Spinal drains were used in 74.5% (n = 35). Spinal cord ischemia developed in 6.4% (n = 3), which resolved in two and improved in one. No retrograde aortic dissections occurred. The 30-day mortality was 4.3% (n = 2); one death was in a patient with rupture. Mean clinical follow-up was 35.1 ± 20.9 months. The 5-year Kaplan-Meier survival was 89% ± 5%. Treatment failure occurred in 18 patients (38.3%): 9 required SAIs, 6 did not have thrombosis of the false lumen in the area of the DRAD DTA, and 4 died, with 1 patient dying during a SAI. No preoperative anatomic factor predicted treatment failure. The 5-year freedom from treatment failure was 54% ± 9%. Including the nine patients who underwent SAI, treatment success was achieved in 85.2% of patients. CONCLUSIONS: In this single-center experience of stent graft therapy for chronic DRAD DTA, treatment success was achieved in 85% of patients after a SAI rate of 20%. No preoperative anatomic factor predicted treatment failure, which occurred in almost 40% of the patients. Identifying predictors of treatment failure may improve future outcomes.

Impaired arteriogenesis in syndecan-1(-/-) mice.

BACKGROUND: Collateral artery development (arteriogenesis) is an important compensatory response to arterial occlusion caused by atherosclerosis. The heparan sulfate proteoglycan syndecan-1 (sdc1) has previously been shown to affect the response to arterial injury but has yet been studied in arteriogenesis. We tested the hypothesis that sdc1 knockout (sdc1(-/-)) mice would revascularize more poorly than wild type (wt) mice, and then used bone marrow transplantation experiments to determine whether sdc1's effect on arteriogenesis was due to its presence in the local tissue environment or in bone marrow derived cells. MATERIALS AND METHODS: Hindlimb ischemia was induced by femoral artery ligation in wt and sdc1(-/-) female mice as well as in wt and sdc1(-/-) female mice transplanted with wt bone marrow or in wt mice transplanted with sdc1(-/-) bone marrow. Blood flow recovery was assessed by laser Doppler perfusion imaging. Arteriogenesis was assessed by measuring the diameter of the dominant collateral pathway after pressure perfusion fixation and intra-aortic contrast injection at 28 d. Immunohistochemistry was used to assess angiogenesis and peri-collateral macrophage infiltration at 7 d, postoperatively. RESULTS: Sdc1(-/-) mice had impaired blood flow recovery in response to hindlimb ischemia. This impaired recovery was not secondary to a defect in capillary angiogenesis nor was it due to decreased peri-collateral macrophage infiltration. Wt bone marrow did not rescue the impaired recovery of sdc1(-/-) mice. CONCLUSIONS: Sdc1 affects arteriogenesis in response to hindlimb ischemia and is required in the local tissue environment for normal arteriogenesis.