Parallel Murine and Human Plaque Proteomics Reveals Pathways of Plaque Rupture.

RATIONALE: Plaque rupture is the proximate cause of most myocardial infarctions and many strokes. However, the molecular mechanisms that precipitate plaque rupture are unknown. OBJECTIVE: By applying proteomic and bioinformatic approaches in mouse models of protease-induced plaque rupture and in ruptured human plaques, we aimed to illuminate biochemical pathways through which proteolysis causes plaque rupture and identify substrates that are cleaved in ruptured plaques. METHODS AND RESULTS: We performed shotgun proteomics analyses of aortas of transgenic mice with macrophage-specific overexpression of urokinase (SR-uPA+/0 mice) and of SR-uPA+/0 bone marrow transplant recipients, and we used bioinformatic tools to evaluate protein abundance and functional category enrichment in these aortas. In parallel, we performed shotgun proteomics and bioinformatics studies on extracts of ruptured and stable areas of freshly harvested human carotid plaques. We also applied a separate protein-analysis method (protein topography and migration analysis platform) to attempt to identify substrates and proteolytic fragments in mouse and human plaque extracts. Approximately 10% of extracted aortic proteins were reproducibly altered in SR-uPA+/0 aortas. Proteases, inflammatory signaling molecules, as well as proteins involved with cell adhesion, the cytoskeleton, and apoptosis, were increased. ECM (Extracellular matrix) proteins, including basement-membrane proteins, were decreased. Approximately 40% of proteins were altered in ruptured versus stable areas of human carotid plaques, including many of the same functional categories that were altered in SR-uPA+/0 aortas. Collagens were minimally altered in SR-uPA+/0 aortas and ruptured human plaques; however, several basement-membrane proteins were reduced in both SR-uPA+/0 aortas and ruptured human plaques. Protein topography and migration analysis platform did not detect robust increases in proteolytic fragments of ECM proteins in either setting. CONCLUSIONS: Parallel studies of SR-uPA+/0 mouse aortas and human plaques identify mechanisms that connect proteolysis with plaque rupture, including inflammation, basement-membrane protein loss, and apoptosis. Basement-membrane protein loss is a prominent feature of ruptured human plaques, suggesting a major role for basement-membrane proteins in maintaining plaque stability.

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.

Simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging: Comparison with contrast-enhanced MR angiography for measuring carotid stenosis.

PURPOSE: To evaluate in a proof-of-concept study the feasibility of Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP) imaging as a clinical magnetic resonance angiography (MRA) technique for measuring carotid stenosis. There is a growing interest in detecting intraplaque hemorrhage (IPH) during the clinical management of carotid disease, yet luminal stenosis has remained indispensable during clinical decision-making. SNAP imaging has been proposed as a novel IPH imaging technique that provides carotid MRA with no added scan time. Flowing blood shows negative signal on SNAP because of phase-sensitive inversion recovery. MATERIALS AND METHODS: In all, 58 asymptomatic subjects with 16-79% stenosis on ultrasound were scanned at 3T by SNAP with 0.8 mm isotropic resolution and 16 cm longitudinal coverage. Two readers measured luminal stenosis of bilateral carotid arteries (n = 116) on minimum intensity projections of SNAP using the NASCET criteria. In the subset (48 arteries) with contrast-enhanced (CE) MRA available for comparison, luminal stenosis was also measured on maximum intensity projections of CE-MRA. RESULTS: Intraclass correlation coefficients (ICCs) with 95% confidence intervals were 0.94 (0.90-0.96) and 0.93 (0.88-0.96) for intra- and interreader agreement on stenosis measurements, respectively. Corresponding kappas for grading stenosis (0-29%, 30-69%, 70-99%, and 100%) were 0.79 (0.67-0.89) and 0.80 (0.68-0.90). Agreement between SNAP and CE-MRA was high (ICC: 0.95 [0.90-0.98]; kappa: 0.82 [0.71-0.93]). CONCLUSION: As a dedicated IPH-imaging sequence, SNAP also provided carotid stenosis measurement that showed high intra- and interreader consistency and excellent agreement with CE-MRA. Further comparisons with digital subtraction angiography and other noninvasive techniques are warranted. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1045-1052.

Tissue Factor Activity in Dialysis Access Grafts.

BACKGROUND: Intimal hyperplasia at the venous anastomosis of dialysis grafts causes early failure. We developed a sheep model of arteriovenous prosthetic grafts that fail rapidly due to intimal hyperplasia with histologic features nearly identical to human access grafts. A prominent feature of lesion development in this model is formation of luminal thrombus that becomes organized into stenosing lesions by macrophage and myofibroblast infiltration. To better understand this process, we examined the presence and activity of tissue factor (TF) in this system. This protein is the physiological initiator of coagulation in vivo and is known to contribute to development of intimal hyperplasia after vascular injury. METHODS: Expanded polytetrafluorethylene (ePTFE) grafts were placed between the carotid artery and external jugular vein in sheep. Grafts were examined for luminal TF activity using a novel ex vivo assay. In a separate series of grafts, immunohistochemistry was used to localize smooth muscle cells, monocytes, and TF protein. RESULTS: At 2 days, luminal TF activity already was higher in the venous and arterial end of the graft than in the adventitia. This high level of activity persisted at 8 weeks. TF activity was higher in the venous end of the grafts than in the arterial end at 2 and 8 weeks (40% and 47% increase, n = 5, n = 3, respectively, P < 0.05). Immunohistochemistry revealed TF protein localized in regions with or adjacent to fibrin accumulation and often in regions close to the lumen. CONCLUSIONS: This study further examines the development of intimal hyperplasia in ePTFE dialysis access grafts. In this model, TF levels on the luminal surface were increased throughout the arteriovenous grafts and the adjacent vessels as early as 2 days after engraftment and for as long as 8 weeks thereafter. The highest levels of activity were found in the venous end of the graft, where hyperplasia is most robust. Increased activity of TF is associated with luminal thrombus, which provides a scaffolding for development of intimal hyperplasia. These findings present an opportunity to develop strategies to limit TF activity within the graft. Further studies using agents delivered locally or incorporated into the graft matrix to block the luminal activity of TF are warranted.

Long-term comparison of endovascular and open repair of abdominal aortic aneurysm.

BACKGROUND: Whether elective endovascular repair of abdominal aortic aneurysm reduces long-term morbidity and mortality, as compared with traditional open repair, remains uncertain. METHODS: We randomly assigned 881 patients with asymptomatic abdominal aortic aneurysms who were candidates for both procedures to either endovascular repair (444) or open repair (437) and followed them for up to 9 years (mean, 5.2). Patients were selected from 42 Veterans Affairs medical centers and were 49 years of age or older at the time of registration. RESULTS: More than 95% of the patients underwent the assigned repair. For the primary outcome of all-cause mortality, 146 deaths occurred in each group (hazard ratio with endovascular repair versus open repair, 0.97; 95% confidence interval [CI], 0.77 to 1.22; P=0.81). The previously reported reduction in perioperative mortality with endovascular repair was sustained at 2 years (hazard ratio, 0.63; 95% CI, 0.40 to 0.98; P=0.04) and at 3 years (hazard ratio, 0.72; 95% CI, 0.51 to 1.00; P=0.05) but not thereafter. There were 10 aneurysm-related deaths in the endovascular-repair group (2.3%) versus 16 in the open-repair group (3.7%) (P=0.22). Six aneurysm ruptures were confirmed in the endovascular-repair group versus none in the open-repair group (P=0.03). A significant interaction was observed between age and type of treatment (P=0.006); survival was increased among patients under 70 years of age in the endovascular-repair group but tended to be better among those 70 years of age or older in the open-repair group. CONCLUSIONS: Endovascular repair and open repair resulted in similar long-term survival. The perioperative survival advantage with endovascular repair was sustained for several years, but rupture after repair remained a concern. Endovascular repair led to increased long-term survival among younger patients but not among older patients, for whom a greater benefit from the endovascular approach had been expected. (Funded by the Department of Veterans Affairs Office of Research and Development; OVER ClinicalTrials.gov number, NCT00094575.).

Pathophysiology of carotid atherosclerosis: Calcification, intraplaque haemorrhage and pulse pressure as key players.

PURPOSE: Intraplaque haemorrhage (IPH) is a well-known risk factor for faster plaque progression (volume increase); however, its etiology is unclear. We aimed at determining what other local plaque- and systemic factors contribute to plaque progression and to the development and progression of IPH. METHODS: We examined 98 asymptomatic participants with carotid plaque using serial multi-contrast magnetic resonance imaging. We measured the percent of wall volume (%WV=100 x [wall volume] / [total vessel volume]) and measured IPH and calcification volumes. We used generalized estimating equations-based regression to analyze predictors of %WV change and new IPH while accounting for covariates (sex, age and statin use), and multiple non-independent observations per participant. RESULTS: Total follow-up was 1.8 ± 0.8 years on average. The presence of IPH (ß: 0.6 %/y, p = 0.033) and calcification (ß: 1.2 %/y, p = 0.028) were each associated with faster plaque progression. New IPH, detected on a subsequent scan in 4 % of arteries that did not initially have IPH, was associated with larger calcification (odds ratio [OR]: 2.6 per 1-SD increase, p = 0.038) and higher pulse pressure (OR: 2.3 per 1-SD increase, p = 0.016). Larger calcification was associated with greater increases in pulse pressure (ß: 1.4 mm Hg/y per 1-SD increase, p = 0.040). CONCLUSIONS: IPH and calcification are each independently associated with faster plaque progression. The association of carotid calcification to increased pulse pressure and new IPH development suggests a possible mechanism by which calcification drives IPH development and plaque progression.

Favorable discharge disposition and survival after successful endovascular repair of ruptured abdominal aortic aneurysm.

OBJECTIVE: Endovascular repair of ruptured abdominal aortic aneurysm (rEVAR) has been shown to improve perioperative outcomes compared with open surgical repair (OSR). Follow-up of these patients, however, is lacking. In this study, we compare the discharge disposition and midterm survival of ruptured aneurysm patients who survived treatment with either rEVAR or OSR. METHODS: We performed an institutional review board-approved, single-institution, retrospective review of all patients with ruptured abdominal aortic aneurysms (rAAAs) admitted from July 2007 to February 2012. Primary outcomes were discharge disposition and midterm survival (>30 days after the index operation). We also evaluated compliance with follow-up and prevalence of endoleak. RESULTS: A total of 118 patients were analyzed. Eight patients received only comfort care, 10 died in the operating room, 39 underwent OSR, and 61 had rEVAR. Average age and sex were similar (OSR, 77 ± 7.8 years, 85% male; rEVAR, 74 ± 7.4 years, 79% male). Seventy-two survived to discharge (54% OSR [21/39]; 84% rEVAR [51/61]; P = .001). OSR patients had longer lengths of intensive care unit and total length of stay than rEVAR (11.8 ± 10.4/23 ± 16.4 days vs 6.3 ± 8.5/12.3 ± 13.0 days; P = .002/.02). Only 19% (4/21) of patients were discharged home after OSR, rather than to a skilled nursing facility. Significantly more rEVAR patients were discharged to home rather than a skilled nursing facility (65%; 33/51) (P = .0004). Overall, the follow-up rate for determination of survival for patients who lived past 30 days was 86% (56/65; median, 14 months; 25th-75th interquartile, 3.1-27.8). Multivariable logistic regression revealed only the type of procedure performed and perioperative hypotension predicted discharge destination. Kaplan-Meier analysis revealed a significant midterm survival benefit for patients after rEVAR compared with OSR (P = .01, log-rank). Subgroup analysis of survivors past 30 days revealed similar rates of midterm survival (P = .7, log-rank). Overall, midterm relative risk reduction for death after rEVAR vs OSR was 35% (95% confidence interval, 0.06-0.59). CONCLUSIONS: We have previously demonstrated that successful utilization of rEVAR improves the early survival of rAAA patients compared with OSR. This study shows that more patients are able to be discharged to home after rEVAR and that the early survival advantage is continued in midterm follow-up, suggesting that rEVAR should be attempted first when feasible. Further studies are needed to determine the long-term durability of endovascular repair in the management of rAAA as well as the impact on cost and long-term quality of life.

Low levels of a natural IgM antibody are associated with vein graft stenosis and failure.

BACKGROUND: All humans have natural, protective antibodies directed against phosphorylcholine (PC) epitopes, a common inflammatory danger signal appearing at sites of cell injury, oxidative stress, and on bacterial capsules. In large human cohorts, low levels of anti-PC IgM were associated with a significantly increased risk of stroke or myocardial infarction. However, it is not known if these antibodies protect against the premature closure of arterial reconstructions. METHODS: A prospective, observational study of patients undergoing elective, infrainguinal, autogenous vein bypasses for atherosclerotic occlusive disease of the legs was conducted. Clinical data were recorded prospectively, and preoperative levels of anti-PC IgM measured with the CVDefine kit from Athera Biotechnologies (Solna, Sweden). The principal clinical end point was the loss of primary patency (loss of graft flow, or any intervention for stenosis). Patients were followed regularly by duplex ultrasound at 1, 3, 6, 12, 18 months, and yearly thereafter. RESULTS: Fifty-six patients were studied, for an average of 1.3 years. Indications for surgery were claudication (33.9%), ischemic rest pain (17.9%), and ischemia with ulceration or gangrene (48.2%). Seventeen (30.4%) patients experienced loss of primary patency (10 graft occlusions, seven surgical or endovascular revisions of graft stenoses). Kaplan-Meier survival analysis showed that the quartile of patients with the lowest anti-PC IgM levels had significantly worse primary graft patency (log-rank test, P = .0085). Uni- and multivariate Cox proportional hazards analysis revealed that the preoperative anti-PC IgM level was an important predictor of graft failure. Patients with IgM values in the lowest quartile had a 3.6-fold increased risk of graft failure (95% confidence interval: 1.1-12.1), even after accounting for other significant clinical or technical factors such as indication for surgery, site of distal anastomosis, or vein graft diameter. CONCLUSIONS: A naturally occurring IgM antibody directed against the proinflammatory epitope PC may be protective against vein graft stenosis and failure, through anti-inflammatory mechanisms. Measurement of this antibody may be a useful prognostic indicator, although larger studies of more diverse populations will be needed to confirm these results. The biological actions of anti-PC IgM suggest it may be useful in developing immunotherapies to improve bypass longevity.

Mycotic aortic aneurysm caused by haemophilus influenzae group F.

BACKGROUND: Haemophilus influenzae is a rare cause of mycotic aortic aneurysm. We present a case of H. influenzae mycotic aortic aneurysm, which was complicated by prior endovascular stent-graft placement at another facility. METHODS: A 58 year-old man was treated by endograft placement for a presumed penetrating aortic ulcer after having symptoms of abdominal pain and malaise for one month. He presented to our institution 11 days after endograft placement with septic physiology. Repeat computed tomography angiogram demonstrated an inflammatory mass around the distal aorta and right common iliac artery, which had an associated contained rupture. RESULTS: The patient was treated using intravenous antibiotics, axillo-bifemoral bypass followed by endograft explantation and aortic and iliac ligation. Intraoperative cultures grew Haemophilus influenzae, serotype f. CONCLUSIONS: Aortic endografts have been successfully used for treatment of selected mycotic aneurysms, generally after adequate treatment of the primary infection with intravenous antibiotics. This case demonstrates the unfavorable natural history of endograft placement in an unsuspected mycotic aneurysm. A high index of suspicion for possible aortic infection should be maintained for patients with systemic symptoms and unusual aortic pathology prior to choosing endovascular repair.

Three-dimensional ultrasonography measurements after endovascular aneurysm repair.

BACKGROUND: Ultrasonographic (US) assessment of abdominal aortic aneurysms is typically performed by measuring maximal aneurysm diameter from two-dimensional images. These measurements are prone to inaccuracies owing to image planes and interobserver variability. The purpose of this study was to compare the variability in diameter, cross-sectional area (CSA), and volume measurements of abdominal aortic aneurysms obtained using a three-dimensional (3D) US imaging system with those obtained using computed tomographic (CT) angiography, and to determine the reliability of these measures. METHODS: Seven patients in whom endovascular aneurysm repairs were performed underwent CT angiography in addition to a 3D US scan. Measurements computed using 3D surface reconstructions of CT and 3D US scans included maximum diameter, CSA, and aneurysm volume. The seven matched CT and 3D US scans were compared at baseline and 6 to 8 weeks later. RESULTS: The average aneurysm measured 57.2 mm on CT and 56.2 mm on US (P = 0.14). Correlation coefficients for diameter, CSA, and volume were 0.88, 0.90, and 0.93, respectively (all P values < 0.001). A Bland-Altman analysis demonstrated a strong agreement between 92% of the diameter, 96.4% of the CSA, and 100% of the volume measurements. The interrater reliability was remarkably high comparing the modalities (CT vs. US), and ranged from 0.934 to 0.997 for single measurements and 0.965 to 0.998 for all measurements together; moreover, there was a strong reliability when the tests were reviewed 6 to 8 weeks later, with a reliability of 0.962 to 0.998 for single measurements and 0.992 to 0.999 for all tests (all P values < 0.001). CONCLUSIONS: The 3D US is an accurate and noninvasive method of determining aneurysm size and geometry that is reproducible. Volumetric measurements may represent a significant advancement in long-term follow-up after endovascular aneurysm repair.

Genetic variation in LPAL2, LPA, and PLG predicts plasma lipoprotein(a) level and carotid artery disease risk.

BACKGROUND AND PURPOSE: lipoprotein(a) [Lp(a)] level is an established risk factor for coronary artery disease and has been implicated in carotid artery disease (CAAD). The relationship between genetic variation in the LPA gene region and CAAD risk remains unknown. METHODS: we genotyped single nucleotide polymorphisms (SNPs) in the LPAL2, LPA, and PLG regions in 530 individuals with severe CAAD and 770 controls and kringle IV type 2 (KIV2) repeat length in a subset of 90 individuals. RESULTS: nine SNPs collectively accounted for 30% of the variance in Lp(a) level. Six SNPs were associated with Lp(a) level after accounting for KIV2 copy number, and the dominant KIV2 allele combined with these markers explained 60% of the variance in Lp(a) level. Five SNPs, including rs10455872, which had an odds ratio of 2.1 per minor allele and haplotypes formed by rs10455872, rs6919346, and rs3123629, were significant predictors of CAAD. After accounting for Lp(a) level, all evidence of CAAD-genotype association in the LPA region was eliminated. CONCLUSIONS: LPA region SNPs capture some but not all of the effect of KIV2 repeat length on Lp(a) level. There are associations between LPA region SNPs and CAAD that appear to be attributable to effects on Lp(a) level.

Circulating inflammatory cells are associated with vein graft stenosis.

OBJECTIVE: Infrainguinal autogenous vein grafts are especially prone to narrowing and failure, and both inflammatory and thrombotic pathways are implicated. Platelets and monocytes are the key thrombo-inflammatory cells that arrive first at sites of vascular injury. These cells have potent interactions that recruit and activate one another, propagating thrombotic and inflammatory responses within the vessel wall. We therefore hypothesized that elevated levels of platelet-monocyte aggregates (PMA) might be associated with stenosis, and could possibly discriminate between patients with or without vein graft stenosis. METHODS: Thirty-six vascular surgery patients were studied, in a stable quiescent period after infrainguinal autogenous vein graft bypasses for occlusive disease. Eighteen patients had hemodynamically significant graft stenoses confirmed by imaging, and 18 were free from stenosis. The level of PMA in whole blood was quantified after blood draw using two-color flow cytometry. Three measurements were made per sample: the basal, in-vivo level of aggregates (baseline PMA); the predisposition to spontaneously generate PMA (spontaneous PMA); and PMA generation by the addition of exogenous thrombin receptor-activating peptide (stimulated PMA). The baseline, in-vivo level of PMA was estimated by immediate flow analysis. The predisposition to spontaneously generate PMA was measured after in vitro incubation. Responsiveness to thrombin stimulation of the blood was quantified by the in vitro dose response to an exogenous thrombin receptor-activating peptide (sfllrn). RESULTS: Baseline PMA levels were similar in patients with vein graft stenosis vs nonstenosis (14.8% ± 3.2 vs 10.1% ± 1.5, respectively, mean ± SEM). However, patients with stenosis showed higher spontaneous PMA levels (58.5% ± 4.5 vs 28.3% ± 4.3; P < .001) and higher stimulated PMA levels (P < .001; analysis of variance). Covariables of smoking, diabetes, statin, or antithrombotic therapy could not account for these differences. CONCLUSIONS: Platelet-monocyte reactivity may play a role in the development of vein graft stenoses. Those with/without stenosis differed primarily in their threshold, or predisposition to form aggregates (spontaneous PMA), while their basal circulating levels of PMA (baseline PMA) were similar. These measurements may unmask pathologic differences in thrombo-inflammatory responsiveness that are not apparent in basal measurements. Understanding the causes and mechanisms leading to abnormal platelet-monocyte responses may improve approaches to predicting or preventing vein graft stenosis.

Management of ruptured abdominal aortic aneurysm in the endovascular era.

OBJECTIVES: Our institution treats about 30 patients per year with ruptured abdominal aortic aneurysms (rAAA). Between 2002 and 2007, our 30-day mortality averaged 58%. In July 2007, we implemented an algorithm to promote endovascular aneurysm repair (EVAR) when feasible. This report describes the outcome with this approach. METHODS: Data on patients presenting with rAAA between July 1, 2002, and June 30, 2007, were reviewed and used for comparison to prospectively collected data. Data on patients presenting between July 1, 2007, and April 30, 2009, were collected on all patients after implementation of a structured protocol. The primary outcome measure was 30-day mortality. Data were analyzed using logistic regression. Kaplan-Meier survival curves and a log-rank test were performed to compare survival times for three groups (pre-protocol, post-protocol with open surgery, and post-protocol with EVAR). RESULTS: During the study period, 187 patients with rAAA presented to our institution. Before implementation of the algorithm, 131 patients with rAAA presented and 128 were treated. The 30-day mortality rate was 57.8%. After implementation of the protocol, 56 patients with rAAA were managed. Twenty-seven patients (48%) underwent successful EVAR, and 24 patients (43%) underwent open repair. Five patients (9%) underwent comfort care only. In the post-protocol period, 5 patients in the EVAR group (18.5%) and 13 patients in the open group (54.2%) died during the follow-up period for an overall 30-day mortality rate of 35.3% (P = .008 vs 57.8% pre-protocol). After implementation of a structured protocol for managing rAAA, there was a relative risk reduction in 30-day mortality of 35% compared to the time before implementation of the protocol (95% confidence interval [CI], 14%-51%) corresponding to an absolute risk reduction of 22.5% (95% CI, 6.8%-38.2%) and an odds ratio of 0.40 (95% CI, 0.20-0.78; P = .007). After adjusting for key factors predicting mortality, the odds ratio is 0.25 (95% CI, 0.10-0.57; P = .001). CONCLUSION: Use of an algorithm favoring endovascular repair resulted in a highly significant reduction in rAAA mortality in our urban hospital. Thirty-day mortality for open repair was no different between pre- and post-protocol eras. With modern techniques of resuscitation and surgical management, a majority of patients presenting with rAAA can survive.

Proliferative capacity of vein graft smooth muscle cells and fibroblasts in vitro correlates with graft stenosis.

OBJECTIVE: About a quarter of peripheral vein grafts fail due in part to intimal hyperplasia. The proliferative capacity and response to growth inhibitors of medial smooth muscle cells and adventitial fibroblasts in vitro were studied to test the hypothesis that intrinsic differences in cells of vein grafts are associated with graft failure. METHODS: Cells were grown from explants of the medial and adventitial layers of samples of vein grafts obtained at the time of implantation. Vein graft patency and function were monitored over the first 12 months using ankle pressures and Duplex ultrasound to determine vein graft status. Cells were obtained from veins from 11 patients whose grafts remained patent (non-stenotic) and from seven patients whose grafts developed stenosis. Smooth muscle cells (SMCs) derived from media and fibroblasts derived from adventitia were growth arrested in serum-free medium and then stimulated with 1 muM sphingosine-1-phosphate (S1P), 10 nM thrombin, 10 ng/ml epidermal growth factor (EGF), 10 ng/ml platelet-derived growth factor-BB (PDGF-BB), PDGF-BB plus S1P, or PDGF-BB plus thrombin for determination of incorporation of [(3)H]-thymidine into DNA. Cells receiving PDGF-BB or thrombin were also treated with or without 100 microg/ml heparin, which is a growth inhibitor. Cells receiving thrombin were also treated with or without 150 nM AG1478, an EGF receptor kinase inhibitor. RESULTS: SMCs and fibroblasts from veins of patients that developed stenosis responded more to the growth factors, such as PDGF-BB alone or in combination with thrombin or S1P, than cells from veins of patients that remained patent (P = .012). In addition, while PDGF-BB-mediated proliferation of fibroblasts from grafts that remained patent was inhibited by heparin (P < .03), PDGF-BB-mediated proliferation of fibroblasts from veins that developed stenosis was not (P > .5). CONCLUSION: Inherent differences in the proliferative response of vein graft cells to PDGF-BB and heparin may explain, in part, the variability among patients regarding long term patency of vein grafts.

Outcomes following endovascular vs open repair of abdominal aortic aneurysm: a randomized trial.

CONTEXT: Limited data are available to assess whether endovascular repair of abdominal aortic aneurysm (AAA) improves short-term outcomes compared with traditional open repair. OBJECTIVE: To compare postoperative outcomes up to 2 years after endovascular or open repair of AAA in a planned interim report of a 9-year trial. DESIGN, SETTING, AND PATIENTS: A randomized, multicenter clinical trial of 881 veterans (aged > or = 49 years) from 42 Veterans Affairs Medical Centers with eligible AAA who were candidates for both elective endovascular repair and open repair of AAA. The trial is ongoing and this report describes the period between October 15, 2002, and October 15, 2008. INTERVENTION: Elective endovascular (n = 444) or open (n = 437) repair of AAA. MAIN OUTCOME MEASURES: Procedure failure, secondary therapeutic procedures, length of stay, quality of life, erectile dysfunction, major morbidity, and mortality. RESULTS: Mean follow-up was 1.8 years. Perioperative mortality (30 days or inpatient) was lower for endovascular repair (0.5% vs 3.0%; P = .004), but there was no significant difference in mortality at 2 years (7.0% vs 9.8%, P = .13). Patients in the endovascular repair group had reduced median procedure time (2.9 vs 3.7 hours), blood loss (200 vs 1000 mL), transfusion requirement (0 vs 1.0 units), duration of mechanical ventilation (3.6 vs 5.0 hours), hospital stay (3 vs 7 days), and intensive care unit stay (1 vs 4 days), but required substantial exposure to fluoroscopy and contrast. There were no differences between the 2 groups in major morbidity, procedure failure, secondary therapeutic procedures, aneurysm-related hospitalizations, health-related quality of life, or erectile function. CONCLUSIONS: In this report of short-term outcomes after elective AAA repair, perioperative mortality was low for both procedures and lower for endovascular than open repair. The early advantage of endovascular repair was not offset by increased morbidity or mortality in the first 2 years after repair. Longer-term outcome data are needed to fully assess the relative merits of the 2 procedures. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00094575.

Peripheral arterial disease in a multiethnic national sample: the role of conventional risk factors and allostatic load.

BACKGROUND: Limited data exist on the prevalence of peripheral arterial disease (PAD) among ethnically diverse populations. Our objectives were to assess the prevalence of PAD in a multiethnic national sample and examine risk factor control and allostatic load (a marker of dysregulation of the inflammatory, metabolic, and cardiovascular systems) by race/ethnicity among individuals with PAD. METHODS: We analyzed data from the 1999-2002 National Health and Nutrition Examination Survey for individuals aged > or =40 with a measured ankle brachial index (N=5,083). PAD was defined as an ankle brachial index <0.9. We performed bivariate and multivariate analyses to describe the association of race/ethnicity with PAD, controlling for sociodemographic factors, clinical risk factors and allostatic load. RESULTS: Rates of PAD were higher among African Americans (7.8%) than Whites (3.4%) or Mexican Americans (5.1%) (P<.001). African Americans with PAD were more likely to be taking antihypertensive medications, were less likely to report vigorous physical activity, and had higher allostatic load scores than Whites. Although 95% of individuals with PAD report a routine place for care, almost half had a measured blood pressure >140/90 mm Hg, 28% were smokers, and 61% had a cholesterol value > or =200 mg/dL. CONCLUSIONS: Within this nationally representative sample, African Americans had the highest rates of PAD. Although conventional risk factor control, including control of hypertension and hyperlipidemia, were similar between racial groups, African Americans with PAD had higher allostatic load scores. Among all individuals with PAD, evidence showed suboptimal cardiovascular risk factor control.

High resolution FDG-microPET of carotid atherosclerosis: plaque components underlying enhanced FDG uptake.

This study sought to discover which atherosclerotic plaque components co-localize with enhanced [(18)F]-fluorodeoxyglucose (FDG) uptake in carotid positron emission tomography (PET) images. Although in vivo PET currently lacks the resolution, high-resolution ex vivo FDG-microPET with histology validation of excised carotid plaque might accomplish this goal. Thirteen patients were injected with FDG before carotid endarterectomy. After excision, the plaque specimens were scanned by microPET and magnetic resonance imaging, and then serially sectioned for histological analysis. Two analyses were performed using generalized linear mixed models: (1) a PET-driven analysis which sampled high and low FDG uptake areas from PET images to identify their components in matched histology specimens; and (2) a histology-driven analysis where specific plaque components were selected and matched to corresponding PET images. In the PET-driven analysis, regions of high FDG uptake were more likely to contain inflammatory cells (p < 0.001) and neovasculature (p = 0.008) than regions of low FDG uptake. In the histology-driven analysis, regions with inflammatory cells (p = 0.001) and regions with loose extracellular matrix (p = 0.001) were associated with enhanced FDG uptake. Furthermore, areas of complex inflammatory cell infiltrate (co-localized macrophages, lymphocytes and foam cells) had the highest FDG uptake among inflammatory subgroups (p < 0.001). In conclusion, in carotid plaque, regions of inflammatory cell infiltrate, particularly complex one, co-localized with enhanced FDG uptake in high-resolution FDG-microPET images. Loose extracellular matrix and areas containing neovasculature also produced FDG signal. This study points to the potential ability of FDG-PET to detect the cellular components of the vulnerable plaque.

Enhancement of capillary and cellular ingrowth in ePTFE implants with a proangiogenic recombinant construct derived from fibronectin.

Based on our discoveries of a unique, synergistic interplay between vascular endothelial growth factor (VEGF) and specific domains of the matrix protein fibronectin (FN), we used recombinant technology to create a new protein construct derived from the cell-binding and VEGF-binding domains of FN. We wished to test the hypothesis that this prototype recombinant FN (rFN) protein would enhance cellular and capillary ingrowth in vivo into expanded polytetrafluoroethylene (ePTFE) implants. ePTFE disks of high porosity (60 micron internodal distance) were embedded with fibrin gel and heparin, with/without mixtures of VEGF and rFN and were implanted subcutaneously in rats. Control implants embedded with fibrin glue and heparin alone showed an average of 8.5% (±0.51% standard error mean (SEM)) cellular ingrowth. The addition of either VEGF or rFN caused a modest but significant increase in cellular ingrowth (12.7 ± 1% and 11.8 ± 0.98%, respectively, p < 0.004). However, the combination of rFN/VEGF/heparin dramatically increased cellular ingrowth (27.6 ± 1.62%, p < 0.001), compared with all other treatments. Quantification of capillary ingrowth yielded the same pattern. These results suggest that the incorporation of such biological modulators into cardiovascular implants could offer new strategies for the design of a ready-made small diameter prosthetic graft with enhanced capacity for neovascularization and endothelialization.

Inhibition of neointimal hyperplasia in a sheep model of dialysis access failure with the bioabsorbable Vascular Wrap paclitaxel-eluting mesh.

OBJECTIVE: This study evaluated the effect of a bioabsorbable mesh containing paclitaxel on neointimal hyperplasia in a sheep model of dialysis access failure. METHODS: Forty neutered male sheep were randomized to one of five parallel groups: no mesh; or a 3-cm x 6-cm mesh with 0.0, 0.3, 0.7, or 1.2 microg/mm(2) of paclitaxel for a total dose of 0.0, 0.6, 1.3, or 2.2 mg, respectively. Commercially available 6-mm internal diameter expanded polytetrafluoroethylene grafts were surgically placed between the left common carotid artery and the right external jugular vein. For those animals randomized to one of the mesh groups, the mesh was placed around the distal end of the graft and venous anastomosis. Patency was assessed at weekly intervals throughout the study. Animals were euthanized 8 weeks after implantation, and grafts and veins were harvested. After histologic processing, six cross sections were cut at the venous end of the graft and vessel. The primary and secondary efficacy outcome measures, respectively, were the area and capillary density of the neointima at the graft-vein anastomosis. Histologic analyses were also performed to investigate the effects of the paclitaxel-eluting mesh on the anastomotic site. RESULTS: Grafts occluded before the scheduled sacrifice in five animals, and they were excluded from the study and not replaced. Control animals developed significant neointimal hyperplasia at the cross section taken perpendicular to the graft at its most distal end: the neointimal area measured 10.5 +/- 6.8 mm(2) in the no mesh group and 6.4 +/- 3.2 mm(2) in the zero-dose mesh group (P = .28). In contrast, neointimal area was significantly reduced in the paclitaxel mesh groups: 0.9 +/- 1.4 mm(2) in the 0.3 microg/mm(2) group (P = .008 vs zero-dose mesh), 1.3 +/- 1.5 mm(2) in the 0.7 microg/mm(2) group (P = .004 vs zero-dose mesh), and 1.2 +/- 1.4 mm(2) in the 1.2 microg/mm(2) group (P = .008 vs zero-dose mesh). Capillary density in the neointima at the graft-vein anastomosis decreased with paclitaxel and was significantly reduced in the paclitaxel mesh groups with 0.3 and 1.2 mug/mm(2) compared with the zero-dose mesh control (3.6 +/- 2.9 vs 8.9 +/- 5.6 per mm(2) [P = .022] and 1.1 +/- 1.7 vs 8.9 +/- 5.6 per mm(2) [P = .001] respectively). The paclitaxel mesh had no significant effect on healing of the anastomosis or on the thickness of the adjacent vein. CONCLUSIONS: In this model, the paclitaxel-eluting mesh significantly reduced neointimal hyperplasia and neointimal capillary density without apparent toxicity to the adjacent vein.