Effect of junctional reflux on the venous clinical severity score in patients with insufficiency of the great saphenous vein (JURY study)

OBJECTIVE

Effective treatment options are available for chronic venous insufficiency associated with superficial venous reflux. Although many patients with C2 and C3 disease based on the CEAP (Clinical-Etiological-Anatomical-Pathophysiological) classification have combined great saphenous vein (GSV) and saphenofemoral junction (SFJ) reflux, some may not have concomitant SFJ reflux. Several payors have determined that symptom severity in patients without SFJ reflux does not warrant treatment. In patients planned for venous ablation, we tested whether Venous Clinical Severity Scores (VCSS) are equivalent in those with GSV reflux alone compared with those with both GSV and SFJ reflux.

METHODS

This cross-sectional study was conducted at 10 centers. Inclusion criteria were: candidate for endovenous ablation as determined by treating physician; 18 to 80 years of age; GSV reflux with or without SFJ reflux on ultrasound; and C2 or C3 disease. Exclusion criteria were prior deep vein thrombosis; prior vein ablation on the index limb; ilio-caval obstruction; and renal, hepatic, or heart failure requiring prior hospitalization. An a priori sample size was calculated. We used multiple linear regression (adjusted for patient characteristics) to compare differences in VCSS scores of the two groups at baseline, and to test whether scores were equivalent using a priori equivalence boundaries of +1 and -1. In secondary analyses, we tested differences in VCSS scores in patients with C2 and C3 disease separately.

RESULTS

A total of 352 patients were enrolled; 64.2% (n = 226) had SFJ reflux, and 35.8% (n = 126) did not. The two groups did not differ by major clinical characteristics. The mean age of the cohort was 53.9 ± 14.3 years; women comprised 74.2%; White patients 85.8%; and body mass index was 27.8 ± 6.1 kg/m2. The VCSS scores in patients with and without SFJ reflux were found to be equivalent; SFJ reflux was not a significant predictor of VCSS score; and mean VCSS scores did not differ significantly (6.4 vs 6.6, respectively, P = .40). In secondary subset analyses, VCSS scores were equivalent between C2 patients with and without SFJ reflux, and VCSS scores of C3 patients with SFJ reflux were lower than those without SFJ reflux.

CONCLUSIONS

Symptom severity is equivalent in patients with GSV reflux with or without SFJ reflux. The absence of SFJ reflux alone should not determine the treatment paradigm in patients with symptomatic chronic venous insufficiency. Patients with GSV reflux who meet clinical criteria for treatment should have equivalent treatment regardless of whether or not they have SFJ reflux.

Non-high-density lipoprotein cholesterol and treatment targets in vascular surgery patients

INTRODUCTION

Low-density lipoprotein cholesterol (LDL) is a known contributing factor to atherosclerotic cardiovascular disease (ASCVD) and a primary therapeutic target for medical management of ASCVD. Non-high-density lipoprotein cholesterol (non-HDL) has recently been identified as a secondary therapeutic target but is not yet widely used in vascular surgery patients. We sought to assess if vascular surgery patients were undertreated per non-HDL therapeutic guidelines.

METHODS

This was an observational study that used a single-center database to identify a cohort of adult patients who received care from a vascular surgery provider from 01/2001 to 07/2021. ICD-9/10-CM codes were used to identify patients with a medical history of hyperlipidemia (HLD), coronary artery disease (CAD), cerebrovascular occlusive disease (CVOD), peripheral artery disease (PAD), hypertension (HTN), or diabetes mellitus (DM). Patient smoking status and medications were also identified. Lab values were obtained from the first and last patient encounter within our system. Primary outcomes were serum concentrations of LDL and non-HDL, with therapeutic thresholds defined as 70 mg/dL and 100 mg/dL, respectively.

RESULTS

The cohort included 2465 patients. At first encounter, average age was 59.3 years old, 21.4% were on statins, 8.4% were on a high-intensity statin, 25.7% were diagnosed with HLD, 5.2% with CAD, 15.3% with PAD, 26.3% with DM, 18.6% with HTN, and 2.1% with CVOD. At final encounter, mean age was 64.8 years, 23.5% were on statins with 10.1% on high-intensity statin. Diagnoses frequency did not change at final encounter. At first encounter, nearly two-thirds of patients were not at an LDL <70 mg/dL (62.3%) or non-HDL <100 mg/dL (66.0%) with improvement at final encounter to 45.2 and 40.5% of patients not at these LDL or non-HDL treatment thresholds, respectively. Patients on statins exhibited similar trends with 51.1 and 50.1% of patients not at LDL or non-HDL treatment thresholds at first encounter and 39.9 and 35.4% not at LDL or non-HDL treatment thresholds at last encounter. Importantly, 6.9% of patients were at LDL but not non-HDL treatment thresholds.

DISCUSSION

Among vascular surgery patients, over half did not meet non-HDL targets. These results suggest that we may be vastly under-performing adequate medical optimization with only about one-fourth of patients on a statin at their final encounter and approximately one-tenth of patients being treated with a high-intensity statin. With recent evidence supporting non-HDL as a valuable measurement for atherosclerotic risk, there is potential to optimize medical management beyond current high-intensity statin therapy. Further investigation is needed regarding the risk of adverse events between patients treated with these varied therapeutic targets.

Superior mesenteric aneurysm associated with median arcuate ligament syndrome and a single celiacomesenteric trunk

Median arcuate ligament syndrome (MALS) is known to promote arterial collateral circulation development from mesenteric vessel compression and can lead to the development of visceral aneurysms. These aneurysms are often diagnosed at the time of rupture and pose a significant morality risk without appropriate intervention. A celiacomesenteric trunk is a rare anatomic variant in which the celiac artery and superior mesenteric artery share a common origin and has been postulated as a risk factor for developing MALS. In this report, we present a novel case of MALS in a patient with a celiacomesenteric trunk and a superior mesenteric artery aneurysm.

Thromboembolic outcomes are decreased with the use of a standardized venous thromboembolism risk assessment and prophylaxis protocol for patients undergoing superficial venous procedures

OBJECTIVE

Patients with venous insufficiency can be treated with ablation or phlebectomy, or both. Patients undergoing superficial venous procedures have an elevated risk of deep vein thrombosis (DVT) and pulmonary embolism (PE). At our institution, we initiated a standardized protocol in which patients with a Caprini score (2005 version) of ≥8 are treated with 1 week of prophylactic anticoagulation after the procedure. Duplex ultrasound was performed at 1 week and then within 90 days after the procedure. This aim of the present study was to determine the thrombotic and clinical outcomes after superficial vein procedures using a standardized protocol for DVT/PE risk assessment and prophylaxis.

METHODS

We performed a retrospective analysis of prospectively collected data of superficial vein procedures from 2015 to 2021 at a single center. The patient demographics, CEAP (Clinical-Etiology-Anatomy-Pathophysiology) clinical class, venous clinical severity score, patient-reported outcomes, treatment type, Caprini scores, pre- and postoperative anticoagulation use, and outcomes were collected. Descriptive statistics were used for the patient demographics, procedure details, and unadjusted surgical outcomes. Multivariable logistic regression was used to evaluate the relationship between procedure type and DVT and PE after adjusting for patient characteristics, disease severity, periprocedural anticoagulation, and Caprini score.

RESULTS

A total of 1738 limbs were treated with ablation (n = 820), phlebectomy (n = 181), or ablation and phlebectomy (n = 737). More patients were women (67.1%) and White (90.9%). The overall incidence of DVT/PE was 1.4%. Patients undergoing ablation with phlebectomy had higher rates of DVT/PE (2.7%) than those undergoing ablation (0.2%) or phlebectomy alone (1.7%; P < .01). However, only 30% of DVTs were above the knee. On multivariate analysis, only the procedure type predicted for DVT/PE. However, patients undergoing ablation and phlebectomy achieved better patient-reported outcomes (Caprini score, 5.9) compared with those undergoing ablation (Caprini score, 7.2) or phlebectomy (Caprini score, 7.9) alone (P < .01). The best improvement in the venous clinical severity score was seen with phlebectomy alone.

CONCLUSIONS

The expected difference in the DVT/PE rates between high- and low-risk groups did not materialize in our patients, perhaps secondary to the additional chemoprophylaxis prescribed for the high-risk cohort (Caprini score, ≥8). These results call for a randomized trial to assess the efficacy of a standardized protocol in the reduction of DVT/PE after superficial vein procedures.

Anatomically Complete Supraclavicular Reoperation for Recurrent Neurogenic Thoracic Outlet Syndrome: Clinical Characteristics, Operative Findings, and Long-term Outcomes

BACKGROUND

The clinical outcomes of reoperations for recurrent neurogenic thoracic outlet syndrome (NTOS) remain undefined.

METHODS

From 2009 to 2019, 90 patients with recurrent NTOS underwent anatomically complete supraclavicular reoperation after previous operation(s) performed at other institutions using either supraclavicular (Prev-SC = 48), transaxillary (Prev-TA = 31), or multiple/combination (Prev-MC = 11) approaches. Prospectively maintained data were analyzed retrospectively.

RESULTS

The mean patient age was 39.9 ± 1.4 years, 72% were female, and the mean interval after previous operation was 4.1 ± 0.6 years. The mean Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score was 62 ± 2, reflecting substantial preoperative disability. Residual scalene muscle was present in 100% Prev-TA, 79% Prev-SC, and 55% Prev-MC (P < .05). Retained/residual first rib was present in 90% Prev-TA, 75% Prev-SC, and 55% Prev-MC (P < .05). There were no differences in operative time (overall 210 ± 5 minutes), length of hospital stay (4.7 ± 0.2 days), or 30-day readmissions (7%). During follow-up of 5.6 ± 0.3 years, the improvement in QuickDASH scores was 21 ± 2 (36% ± 3%) (P < .01) and patient-rated outcomes were excellent in 10%, good in 36%, fair in 43%, and poor in 11%.

CONCLUSIONS

Anatomically complete decompression for recurrent NTOS can be safely and effectively accomplished by supraclavicular reoperation, regardless of the type of previous operation. Residual scalene muscle and retained/residual first rib are more frequently encountered after transaxillary operations than after supraclavicular or multiple/combined operations. Supraclavicular reoperation can achieve significant symptom reduction and functional improvement for approximately 90% of patients with recurrent NTOS.

A Patient-Centered Design Thinking Workshop to Improve Patient-Provider Communication in Cardiovascular Medicine

Healthcare providers are expected to deliver care improvement solutions that not only provide high quality patient care, but also improve outcomes, reduce costs, ensure safety, and increase patient satisfaction. Human-centered design methodologies, such as design thinking, allow providers to collaboratively ideate solutions with patients and family members. We describe a pilot workshop designed to teach providers the stages of design thinking while working on improving patient-provider communication. Twenty-four providers (physicians, nurses, technical staff, and administrative staff) from multiple cardiovascular units attended the workshop with five former patients and family members from those units. The workshop educated on and guided teams of providers patients and family members through the stages of design thinking (empathy, define, ideate, prototype, test). Pre- and post-event assessments indicated an increase in knowledge of the design thinking methodology and participants’ ability to apply it to a clinical problem. We also present recommendations for designing a successful design thinking workshop.

"Decreasing Postamputation Pain with the Regenerative Peripheral Nerve Interface (RPNI)"

Over 185,000 limb amputations are performed in the United States annually, many of which are due to the sequelae of peripheral vascular disease. Symptomatic neuromas remain a significant source of postamputation morbidity and contribute to both phantom limb (PLP) and residual limb pain (RLP). While many interventions have been proposed for the treatment of symptomatic neuromas, conventional methods lead to a high incidence of neuroma recurrence. Furthermore, these existing methods do not facilitate an ability to properly interface with myoelectric prosthetic devices. The Regenerative Peripheral Nerve Interface (RPNI) was developed to overcome these limitations. The RPNI consists of an autologous free muscle graft secured around the end of a transected nerve. The muscle graft provides regenerating axons with end organs to reinnervate, thereby preventing neuroma formation. We have shown that this simple, reproducible, and safe surgical technique successfully treats and prevents neuroma formation in major limb amputations. In this paper, we describe RPNI surgery in the setting of major limb amputation and highlight the promising results of RPNIs in our animal and clinical studies.

Endovascular surgery is not protective against new persistent opioid use development compared to open vascular surgery

OBJECTIVE

Endovascular techniques continue to be increasingly utilized to treat vascular disease, but the effect of these minimally invasive techniques on opioid use following surgery is not known.

METHODS

Using Medicare data, we identified opioid-naive patients undergoing vascular procedures between 2009 and 2017. We selected patients ≥65 years old with continuous enrollment 12 months before and 6 months after surgery and had no additional operations. We defined new persistent opioid use (NPOU) as one or more opioid prescription fills both between 4-90 and 91-180 days postoperatively. Multivariable regression was performed for risk adjustment, and frequencies of NPOU were estimated between endovascular and open techniques to compare surgical approach.

RESULTS

A total of 77,767 patients were identified, with 2.6% of all patients developing new persistent use. In addition to the identification of several risk factors for new persistent use, patients undergoing endovascular carotid or vertebral interventions were found to have higher adjusted frequencies of persistent use compared to those undergoing open interventions (3.0% vs. 1.8%, p < 0.001) as did those undergoing endovenous compared to open vein procedures (2.2%, vs. 1.6%, p = 0.019). We found no difference for peripheral vascular or aortic/iliac procedures.

CONCLUSIONS

Patients undergoing vascular surgery are at high risk for new persistent use. Undergoing endovascular carotid or venous surgery was associated with an increased risk of NPOU, whereas no differences were found between endovascular and open approaches for peripheral arterial or aortic disease.

Evaluation and treatment of thoracic outlet syndrome during the global pandemic due to SARS-CoV-2 and COVID-19

The global SARS-CoV-2/COVID-19 pandemic has required a reduction in nonemergency treatment for a variety of disorders. This report summarizes conclusions of an international multidisciplinary consensus group assembled to address evaluation and treatment of patients with thoracic outlet syndrome (TOS), a group of conditions characterized by extrinsic compression of the neurovascular structures serving the upper extremity. The following recommendations were developed in relation to the three defined types of TOS (neurogenic, venous, and arterial) and three phases of pandemic response (preparatory, urgent with limited resources, and emergency with complete diversion of resources). • In-person evaluation and treatment for neurogenic TOS (interventional or surgical) are generally postponed during all pandemic phases, with telephone/telemedicine visits and at-home physical therapy exercises recommended when feasible. • Venous TOS presenting with acute upper extremity deep venous thrombosis (Paget-Schroetter syndrome) is managed primarily with anticoagulation, with percutaneous interventions for venous TOS (thrombolysis) considered in early phases (I and II) and surgical treatment delayed until pandemic conditions resolve. Catheter-based interventions may also be considered for selected patients with central subclavian vein obstruction and threatened hemodialysis access in all pandemic phases, with definitive surgical treatment postponed. • Evaluation and surgical treatment for arterial TOS should be reserved for limb-threatening situations, such as acute upper extremity ischemia or acute digital embolization, in all phases of pandemic response. In late pandemic phases, surgery should be restricted to thrombolysis or brachial artery thromboembolectomy, with more definitive treatment delayed until pandemic conditions resolve.

Closed plication is a safe and effective method for treating popliteal vein aneurysm

BACKGROUND

Popliteal vein aneurysms are a rare vascular anomaly first reported in the 1980s. Degeneration of elastic fibers and smooth muscle cell reduction, possibly secondary to inflammation, are implicated as integral steps in the development of these aneurysms. Given the rarity of this clinical entity, significant controversy exists regarding ideal treatment strategies, including the role of observation, medical management with anticoagulation, and surgical intervention. Retrospective reviews have demonstrated a failure rate of >40% with anticoagulation alone, with patients often presenting with pulmonary embolism. This has prompted our institutional preference for surgical management once the aneurysm is identified. Surgical management involves tangential repair with lateral venorrhaphy most commonly, followed in prevalence by aneurysm resection and end-to-end anastomosis either primarily or with vein interposition. Herein, we report our results with venous plications, through both closed and open techniques.

METHODS

We performed a retrospective review of prospectively collected data for 10 patients undergoing popliteal vein plication for treatment of popliteal vein aneurysms. Patient-level characteristics and operative details were examined from periprocedural and follow-up records.

RESULTS

We identified 10 patients undergoing popliteal vein plication, including 9 closed plications and 1 open plication. The average aneurysm size at presentation was 2.35 ± 0.69 cm for closed plication and 4.74 cm for the one open plication. After treatment, the average popliteal vein size was significantly reduced to 1.12 ± 0.45 cm for the closed plications (P < .001 from preprocedural size) and 1.13 cm for the open plication with 100% primary patency. Average follow-up for patients treated with closed plication was 35.0 ± 25.2 months, during which seven (78%) patients had a stable, normal popliteal vein size. One patient with recurrence was diagnosed with Klippel-Trénaunay syndrome. The other had degeneration of the popliteal vein cranial to the previous repair at 39 months after the original operation that required additional plication. The open plication patient experienced a hematoma requiring washout and resulting in a transient peroneal mononeuropathy. There was one case of cellulitis after closed plication but no hematomas within this group.

CONCLUSIONS

Closed plication demonstrated favorable primary patency rates and low recurrence rates, avoiding technical issues or need for early institution of systemic anticoagulation associated with tangential repair and venorrhaphy or resection methods. Closed plication represents an attractive option in patients without luminal thrombus to limit the risk of these postoperative complications and obviates the need for bypass conduit and postoperative anticoagulation.

Exploration of robotic-assisted surgical techniques in vascular surgery

Robotic-assisted surgical approaches for vascular surgery are feasible regarding minimally invasive exposure, dissection, ligation and skeletonization for varicose vein ligation, anterior spine exposure, femoral-popliteal bypass, femoral vein harvest and aortic aneurysm repair. The authors performed a cadaveric exploration to demonstrate proof of concept and feasibility for a robotic-assisted approached. Surgeon autonomy over endoscopic vision, robotic instrumentation and retraction were noted as key benefits over existing open vascular approaches. Robotic-assisted approaches for vascular surgery enable innovative minimally invasive approaches to disease states not amenable to endovascular repair. Potential reductions in paresthesia through nerve identification were noted during a cadaveric exploration for varicose vein ligation in the setting of chronic venous insufficiency. Minimally invasive femoral artery exposure via a retroperitoneal approach could potentially reduce the morbidity associated with the traditional groin incision. Further exploration and procedure refinement are warranted.

The Future of Nanoparticle-Directed Venous Therapy

Nanoparticles, structures of less than 200 nm capable of delivering pharmacotherapeutics to sites of disease, have shown great promise for the treatment of many disease states. While no nanoparticle therapies for deep vein thrombosis are currently approved by the Food and Drug Administration, many of the unique features of these therapies have the potential to treat both deep vein thrombosis and its most significant sequela, postthrombotic syndrome, while limiting the hemorrhagic complications of current antithrombotic therapies. Nanoparticles are complex structures with several important variables that must be considered to engineer effective therapies. This article will review the structure and engineering of nanoparticles, as well as promising molecular targets for future investigation.

Clinical presentation and management of arterial thoracic outlet syndrome

OBJECTIVE

Arterial thoracic outlet syndrome (TOS) is a rare condition characterized by subclavian artery pathology associated with a bony abnormality. This study assessed contemporary clinical management of arterial TOS at a high-volume referral center.

METHODS

A prospectively maintained database was used to conduct a retrospective review of patients undergoing primary or reoperative treatment for arterial TOS during an 8-year period (2008 to 2016). Presenting characteristics, operative findings, and clinical and functional outcomes were evaluated.

RESULTS

Forty patients underwent surgical treatment for arterial TOS, representing 3% of 1401 patients undergoing operations for all forms of TOS during the same interval. Patients were a mean age of 40.3 ± 2.2 years (range, 13-68 years), and 72% were women. More than half presented with upper extremity ischemia/emboli (n = 21) or posterior stroke (n = 2), including eight that had required urgent brachial artery thromboembolectomy. The presentation in 17 (42%) was nonvascular, with 11 having symptoms of neurogenic TOS and six having an asymptomatic neck mass or incidentally discovered subclavian artery dilatation. All patients underwent thoracic outlet decompression (25 supraclavicular, 15 paraclavicular), of which there were 30 (75%) with a cervical rib (24 complete, 6 partial), 5 with a first rib abnormality, 4 with a clavicle fracture, and 1 (reoperation) with no remaining bone abnormality. Subclavian artery reconstruction was performed in 70% (26 bypass grafts, 1 patch, 1 suture repair), and 30% had mild subclavian artery dilatation (<100%) requiring no arterial reconstruction. Mean postoperative length of stay was 5.4 ± 0.6 days. During a mean follow-up of 4.5 ± 0.4 years (range, 0.9-8.1 years), subclavian artery patency was 92%, none had further dilatation or embolism, and chronic symptoms were present in six (4 postischemic/vasospasm, 2 neurogenic). Functional outcomes measured by scores on the 11-item version of the Disability of the Arm, Shoulder and Hand Outcome Measure improved from 39.1 ± 3.8 to 19.2 ± 2.7 (P < .0001).

CONCLUSIONS

This relatively large single-institution series demonstrates the diverse clinical presentation of arterial TOS coincident with a spectrum of bony and arterial pathology. Current surgical protocols can achieve excellent outcomes for this rare and often complicated condition.

Natriuretic Peptide Receptor-C is Up-Regulated in the Intima of Advanced Carotid Artery Atherosclerosis

OBJECTIVE

Natriuretic peptide receptor-C (NPR-C/NPR-3) is a cell surface protein involved in vascular remodelling that is up-regulated in atherosclerosis. NPR-C expression has not been well characterized in human carotid artery occlusive lesions. We hypothesized that NPR-C expression correlates with intimal features of vulnerable atherosclerotic carotid artery plaque.

METHODS

To test this hypothesis, we evaluated NPR-C expression by immunohistochemistry (IHC) in carotid endarterectomy (CEA) specimens isolated from 18 patients. The grade, location, and co-localization of NPR-C in CEA specimens were evaluated using two tissue analysis techniques.

RESULTS

Relative to minimally diseased CEA specimens, we observed avid NPR-C tissue staining in the intima of maximally diseased CEA specimens (65%; p=0.06). Specifically, maximally diseased CEA specimens demonstrated increased NPR-C expression in the superficial intima (61%, p=0.17), and deep intima (138% increase; p=0.05). In the superficial intima, NPR-C expression significantly co-localized with vascular smooth muscle cells (VSMCs) and macrophages. The intensity of NPR-C expression was also higher in the superficial intima plaque shoulder and cap regions, and significantly correlated with atheroma and fibroatheroma vulnerable plaque regions (β=1.04, 95% CI=0.46, 1.64).

CONCLUSION

These findings demonstrate significant NPR-C expression in the intima of advanced carotid artery plaques. Furthermore, NPR-C expression was higher in vulnerable carotid plaque intimal regions, and correlate with features of advanced disease. Our findings suggest that NPR-C may serve as a potential biomarker for carotid plaque vulnerability and progression, in patients with advanced carotid artery occlusive disease.

Abstract 141: Anti-thrombin Perfluorocarbon Nanoparticles Decrease Clot Burden in a Murine Model of Venous Thrombosis

Objective: Venous thromboembolism (VTE) afflicts nearly an million Americans with significant mortality and long-term morbidity. Current medical treatment regimens pose significant bleeding risks and recurrence risks. The purpose of this work is to determine if anti-thrombin perfluorocarbon nanoparticles (NP-PPACK) can attenuate clot progression after vascular injury in a murine model of venous thrombosis.

Methods: Male, C57 black-6 mice underwent inferior vena cava (IVC) ligation through an institutionally approved protocol. Following ligation, groups of ten mice were randomized to receive intravenous, weight-based (1 ml/kg) tail vein injections of saline, plain nanoparticles, NP-PPACK or heparin (80 units/kg). After 6 hours the animals were sacrificed, IVC with clot excised and weight and length recorded. Clot integrity (N=4) analysis was then performed by incubating clots with 750 units of streptokinase for 90 minutes at 37 degrees Celsius, removing liquid clot and recording the percent change in clot weight.

Results: There was a significant difference in clot burden between NP-PPACK and the control group (0.59 mg/mm ± 0.063 vs. 1.26mg/mm ± 0.85, p=.0001). Immunofluorescent histology performed on a subgroup of animals verified nanoparticle tracking to venous thrombus. Additionally, using exogenous clot lysis as a surrogate for clot integrity, NP-PPACK treated animals exhibited a trend towards enhanced lysis over saline treatments (change in clot weight over 90 minutes: 57.8 ±14.4 vs. 21.5 ± 7.49, NP PPACK vs saline p=.067).

Conclusions: This initial work demonstrates that NP-PPACK significantly decreases clot burden by local targeting and reduces clot strength in this model of VTE. We have shown previously that the system is locally active for hours against thrombosis yet produces no sustained systemic anticoagulant effect beyond 60 minutes, indicative of its significant safety margin for clinical application.

Oximetric angiosome imaging in diabetic feet

PURPOSE

To develop a noncontrast oximetric angiosome imaging approach to assess skeletal muscle oxygenation in diabetic feet.

MATERIALS AND METHODS

In four healthy and five subjects with diabetes, the feasibility of foot oximetry was examined using a 3T clinical magnetic resonance imaging (MRI) scanner. The subjects' feet were scanned at rest and during a toe-flexion isometric exercise. The oxygen extraction fraction of skeletal muscle was measured using a susceptibility-based MRI method. Our newly developed MR foot oximetric angiosome model was compared with the traditional angiosome model in the assessment of the distribution of oxygen extraction fraction.

RESULTS

Using the traditional angiosome during the toe-flexion exercise, the oxygen extraction fraction in the medial foot of healthy subjects increased (4.9 ± 3%) and decreased (-2.7 ± 4.4%) in subjects with diabetes (difference = 7.6%; 95% confidence interval = -13.7 ± 1.4; P = 0.02). Using the oximetric angiosome, the percent difference in the areas of oxygen extraction fraction within the 0.7-1.0 range (expected oxygen extraction fraction during exercise) between rest and exercise was higher in healthy subjects (8 ± 4%) than in subjects with diabetes (4 ± 4%; P = 0.02).

CONCLUSION

This study demonstrates the feasibility of measuring skeletal muscle oxygen extraction fraction in the foot muscle during a toe-flexion isometric exercise. Instead of assessing oxygen extraction fraction in a foot muscle region linked to a supplying artery (traditional angiosome), the foot oximetric angiosome model assesses oxygen extraction fraction by its different levels in all foot muscle regions and thus may be more appropriate for assessing local ischemia in ulcerated diabetic feet. J. Magn. Reson. Imaging 2016. J. MAGN. RESON. IMAGING 2016;44:940-946.

Antithrombin nanoparticles inhibit stent thrombosis in ex vivo static and flow models

OBJECTIVE

Despite significant advances in intravascular stent technology, safe prevention of stent thrombosis over prolonged periods after initial deployment persists as a medical need to decrease device failure. The objective of this project was to assess the potential of perfluorocarbon nanoparticles (NP) conjugated with the direct thrombin inhibitor D-phenylalanyl-L-prolyl-L-arginyl chloromethylketone (PPACK-NP) to inhibit stent thrombosis.

METHODS

In a static model of stent thrombosis, 3 × 3-mm pieces of stainless steel coronary stents were cut and adsorbed with thrombin to create a procoagulant surface that would facilitate thrombus development. After treatment with PPACK-NP or control NP, stents were exposed to platelet-poor plasma (PPP) or platelet-rich plasma (PRP) for set time points up to 60 minutes. Measurements of final clot weight in grams were used for assessing the effect of NP treatment on limiting thrombosis. Additionally, groups of stents were exposed to flowing plasma containing various treatments (saline, free PPACK, control NP, and PPACK-NP) and generated thrombi were stained and imaged to investigate the treatment effects of PPACK-NP under flow conditions.

RESULTS

The static model of stent thrombosis used in this study indicated a significant reduction in thrombus deposition with PPACK-NP treatment (0.00067 ± 0.00026 g; n = 3) compared with control NP (0.0098 ± 0.0015 g; n = 3; P = .026) in PPP. Exposure to PRP demonstrated similar effects with PPACK-NP treatment (0.00033 ± 0.00012 g; n = 3) vs control NP treatment (0.0045 ± 0.00012 g; n = 3; P = .000017). In additional studies, stents were exposed to both PRP pretreated with vorapaxar and PPACK-NP, which illustrated adjunctive benefit to oral platelet inhibitors for prevention of stent thrombosis. Additionally, an in vitro model of stent thrombosis under flow conditions established that PPACK-NP treatment inhibited thrombus deposition on stents significantly.

CONCLUSIONS

This study demonstrates that antithrombin perfluorocarbon NPs exert marked focal antithrombin activity to prevent intravascular stent thrombosis and occlusion.

Antithrombin nanoparticles improve kidney reperfusion and protect kidney function after ischemia-reperfusion injury

In the extension phase of acute kidney injury, microvascular thrombosis, inflammation, vasoconstriction, and vascular endothelial cell dysfunction promote progressive damage to renal parenchyma after reperfusion. In this study, we hypothesized that direct targeting and pharmaceutical knockdown of activated thrombin at the sites of injury with a selective nanoparticle (NP)-based thrombin inhibitor, PPACK (phenylalanine-proline-arginine-chloromethylketone), would improve kidney reperfusion and protect renal function after transient warm ischemia in rodent models. Saline- or plain NP-treated animals were employed as controls. In vivo 19F magnetic resonance imaging revealed that kidney nonreperfusion was evident within 3 h after global kidney reperfusion at 34 ± 13% area in the saline group and 43 ± 12% area in the plain NP group and substantially reduced to 17 ± 4% (∼50% decrease, P < 0.05) in the PPACK NP pretreatment group. PPACK NP pretreatment prevented an increase in serum creatinine concentration within 24 h after ischemia-reperfusion, reflecting preserved renal function. Histologic analysis illustrated substantially reduced intrarenal thrombin accumulation within 24 h after reperfusion for PPACK NP-treated kidneys (0.11% ± 0.06%) compared with saline-treated kidneys (0.58 ± 0.37%). These results suggest a direct role for thrombin in the pathophysiology of AKI and a nanomedicine-based preventative strategy for improving kidney reperfusion after transient warm ischemia.

Abstract 193: Antithrombin Perfluorocarbon Nanoparticles Ameliorate Renal Injury Following Transient Warm Ischemia

Objective: Thrombin mediated microvascular thrombosis plays a crucial role in the pathogenesis of acute renal reperfusion injury following transient ischemia. We hypothesize that anti-thrombin nanoparticles will ameliorate acute renal injury by inhibiting microvascular thrombosis.

Methods: Adult, male Sprague Dawley rats were randomized into two groups of 5 to receive tail vein injections of saline or nanoparticles loaded with Phe[D]-Pro-Arg-Chloromethylketone (NP-PPACK). Immediately following injection, all animals underwent operative bilateral renal artery occlusion to create 45 minutes of warm ischemia, followed by restoration of renal blood flow. Blood samples were drawn daily and animals were euthanized on day 1 or 7 for histologic analysis of kidney injury (H&E, TUNEL and thrombin staining).

Results: Histologic analysis of renal tissue revealed significant apoptosis, necrosis and thrombin accumulation 1 day after ischemia-reperfusion, confirming acute kidney injury. The peak creatinine (mg/dl) on day 1 was significantly lower in NP-PPACK treated animals (0.57 +/- 0.07 (SEM)) than in saline treated controls (1.40 +/- 0.20 (SEM); p-value <0.01). Furthermore, animals treated with NP-PPACK continued to exhibit less renal dysfunction for 7 days after injury (Figure 1).

Conclusion: Histologically confirmed intrarenal thrombosis was detected one day after ischemia-reperfusion injury. Targeted inhibition of thrombin with NP-PPACK prevented a decline in renal function following transient occlusion. Future work will focus on defining the underlying mechanisms of this effect.

Early effectiveness of isolated pectoralis minor tenotomy in selected patients with neurogenic thoracic outlet syndrome

OBJECTIVE

This study evaluated the early effectiveness of isolated pectoralis minor tenotomy (PMT) in the surgical treatment of selected patients with neurogenic thoracic outlet syndrome (NTOS) compared with supraclavicular decompression (SCD; as scalenectomy, neurolysis, and first rib resection) plus PMT (SCD+PMT).

METHODS

Data were obtained for 200 patients undergoing operative treatment for disabling NTOS between 2008 and 2011. Isolated PMT was offered to 57 patients with physical examination findings limited to the subcoracoid space, and SCD+PMT was offered to 143 with scalene triangle and subcoracoid findings. Functional outcomes were assessed before and 3 months after surgery using the Disabilities of the Arm, Shoulder and Hand (DASH) survey and related instruments.

RESULTS

There were no significant differences (P > .05) between PMT and SCD+PMT patients with respect to age (overall, 37 ± 1 years), sex (73% women), side affected (52% right, 14% bilateral), or the frequency of various NTOS symptoms, but fewer PMT patients had a bony anomaly (0% vs 18%; P < .01) or a history of injury (35% vs 61%; P < .01). Mean preoperative DASH scores were similar between PMT and SCD+PMT groups (49.9 ± 3.6 vs 50.8 ± 1.6), but previous use of opiate pain medications was higher in PMT patients (47% vs 20%; P = .0004). PMT was conducted as an outpatient procedure, whereas the mean hospital stay after SCD+PMT was 4.8 ± 0.1 days, with two patients (1%) requiring early reoperations for persistent lymph leaks. Mean DASH scores 3 months after surgery were significantly improved after isolated PMT (29.6 ± 4.2; P < .01) and SCD+PMT (41.5 ± 2.2; P < .01), but the mean extent of improvement in DASH scores was not significantly different in PMT (32% ± 9%) vs SCD+PMT (19% ± 5%). There were also no significant differences in the proportion of PMT vs SCD+PMT patients demonstrating improvement in functional outcome measures (75% vs 72%) or in overall use of opiate medications (35% vs 27%).

CONCLUSIONS

Isolated PMT is a low-risk outpatient procedure that is effective for the treatment of selected patients with disabling NTOS, with early outcomes similar to SCD+PMT. These findings emphasize the importance of recognizing subcoracoid brachial plexus compression as part of the spectrum of NTOS and support the role of PMT in surgical management.

Supraclavicular decompression for neurogenic thoracic outlet syndrome in adolescent and adult populations

OBJECTIVE

This study was conducted to better define clinical results and understand factors determining responsiveness to surgical treatment for neurogenic thoracic outlet syndrome (NTOS) in adolescent and adult populations.

METHODS

A retrospective review was conducted for 189 patients with disabling NTOS who underwent primary supraclavicular decompression (scalenectomy, brachial plexus neurolysis and first rib resection, with or without pectoralis minor tenotomy) from April 2008 to December 2010. Clinical characteristics were compared between 35 adolescent patients (aged<21 years) and 154 adults (aged>21 years). Functional outcome measures were assessed before surgery and at 3- and 6-month follow-up using a composite NTOS Index combining the Disabilities of the Arm, Shoulder and Hand (DASH) survey, the Cervical-Brachial Symptom Questionnaire (CBSQ), and a 10-point visual analog scale (VAS) for pain.

RESULTS

Adolescent and adult patients were not significantly different with respect to sex (overall 72.5% female), side affected (58.7% right, 60.3% dominant limb), bony anomalies (23.3%), previous injury (55.6%), coexisting pain disorders (11.1%), and positive responses to scalene muscle anesthetic blocks (95.6%). Compared with adults, adolescent patients had a significantly (P<.05) lower incidence of depression (11.4% vs 41.6%), motor vehicle injury (5.7% vs 20.1%), previous operations (11.4% vs 29.9%), preoperative use of opiate medications (17.1% vs 44.8%), and symptom duration>2 years (24.2% vs 50.0%). Mean preoperative NTOS Index (scale 0-100) was significantly lower in adolescent vs adult patients (46.5±3.6 vs 58.5±1.7; P=.009), and hospital length of stay was 4.4±0.2 vs 4.9±0.1 days (P=.03), but the rate of postoperative complications was no different (overall, 4.2%). Although both groups exhibited significant improvement in functional outcome measures at 3 and 6 months, adolescent patients had significantly lower NTOS Index (10.4±3.1 vs 39.3±3.3; P<.001) and use of opiate medications (11.4% vs 47.4%; P<.001) compared with adults.

CONCLUSIONS

Adolescents undergoing supraclavicular decompression for NTOS had more favorable preoperative characteristics and enhanced 3-month and 6-month functional outcomes than adults. Further study is needed to delineate the age-dependent and independent factors that promote optimal surgical outcomes for NTOS.

Abstract 405: Vascular Smooth Muscle Cells (VSMCs) from Abdominal Aortic Aneurysms (AAA) Avidly Take Up Oxidized Cholesterol (oxChol) with Unique Responses Compared with VSMCs from Nonaneurysmal Aorta (NAA)

Objective: We sought to determine if VSMCs from AAA respond to oxChol exposure in a manner which may promote aortic matrix damage.

Methods: Early passage VSMCs (5x10 5 ) from human AAA, Carotid plaques (CP) and nAA were compared after exposure to media with oxChol for 72 hours. Cells were counted and stained with Oil Red O, and staining was graded on a 0-4 scale, by 5 blinded experts. Conditioned media (CM) was assayed by ELISA for MMP-2, and corrected for cell number (mean±SE).

Results: The average grade of Oil Red O stain (Fig 1) of VSMCs from AAA was 2.89 +/- 0.225, CEA plaques was 3.14 +/- 0.151 and nAA was 1.76 +/- 0.258. Cholesterol uptake was significantly different for AAA vs. nAA (p=.015) and CEA vs. nAA (p=.0002), but not between the unstained controls. Cell number (x10 3 ) at harvest after oxChol exposure was significantly greater than media alone for CP (562±48 vs 338±79, P<0.02) and nAA (343±49 vs 250±31), but there was no effect on AAA (339±49 vs 313±43). With exposure to OxChol, MMP-2 concentration in CM from AAA cells was similar to that from CP cells (224±51ng/ml vs. 352±46ng/ml), but production from nAA cells was significantly less than CP (178±61ng/ml, P<0.05) but not compared to AAA.

Conclusion: VSMCs from human AAA exposed to oxChol had significantly increased cholesterol uptake, with MMP-2 production comparable to CP cells. Exposure to oxChol resulted in a mitogenic response in the CEA and nAA cells not seen in the AAA cells. Hypercholesterolemia may promote AAA due to pathologic cellular responses of increased cholesterol uptake, decreased growth and increased protease production. Additional studies are needed to clarify these responses.

Effect of increasing patient age on complication rates following intact abdominal aortic aneurysm repair in the united states1

INTRODUCTION

Advanced age is generally acknowledged as a risk factor for adverse surgical outcomes, but little information exists to define the magnitude of this association from a population-based perspective. This study was undertaken to determine the relation of patient age to complications following abdominal aortic aneurysm (AAA) repair in a population-based experience.

METHODS

This study was based upon data from 6397 patients with a primary diagnosis of intact AAA and a procedure code for repair of AAA from the Nationwide Inpatient Sample (NIS) in 2000. The NIS is a 20% stratified random sample representative of all United States hospitals. Primary outcome variables were postoperative complications determined from secondary diagnostic codes. Adjustment for confounding variables was performed using multiple logistic regression.

RESULTS

At least one complication affected 29% of patients. Increasing age correlated with a higher risk of having one or more complications (51-60 years, 18.8%; 61-70 years, 27.3%; 71-80 years, 31.2%; >80 years, 34.3%; P < 0.01). Comparison of the oldest to the youngest age group revealed an increased incidence of pulmonary insufficiency (13.9% versus 6.4%), pneumonia (7.7% versus 3.0%), reintubation (9.5% versus 3.9%), acute renal failure (8.8% versus 2.5%), myocardial infarction (4.3% versus 1.6%), and mortality (7.9% versus 1.1%). The association of increasing age to complications and mortality persisted after adjusting for patient case-mix.

CONCLUSIONS

Older patient age is independently associated with an increased risk of major postoperative complications after AAA repair. The increasing age of the United States population will compound this healthcare problem. Quality improvement efforts must focus on minimizing complication rates in elderly patients undergoing common vascular surgical procedures including AAA repair.