Chronic mesenteric ischemia: Clinical practice guidelines from the Society for Vascular Surgery.

BACKGROUND: Chronic mesenteric ischemia (CMI) results from the inability to achieve adequate postprandial intestinal blood flow, usually from atherosclerotic occlusive disease at the origins of the mesenteric vessels. Patients typically present with postprandial pain, food fear, and weight loss, although they can present with acute mesenteric ischemia and bowel infarction. The diagnosis requires a combination of the appropriate clinical symptoms and significant mesenteric artery occlusive disease, although it is often delayed given the spectrum of gastrointestinal disorders associated with abdominal pain and weight loss. The treatment goals include relieving the presenting symptoms, preventing progression to acute mesenteric ischemia, and improving overall quality of life. These practice guidelines were developed to provide the best possible evidence for the diagnosis and treatment of patients with CMI from atherosclerosis. METHODS: The Society for Vascular Surgery established a committee composed of vascular surgeons and individuals experienced with evidence-based reviews. The committee focused on six specific areas, including the diagnostic evaluation, indications for treatment, choice of treatment, perioperative evaluation, endovascular/open revascularization, and surveillance/remediation. A formal systematic review was performed by the evidence team to identify the optimal technique for revascularization. Specific practice recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation system based on review of literature, the strength of the data, and consensus. RESULTS: Patients with symptoms consistent with CMI should undergo an expedited workup, including a computed tomography arteriogram, to exclude other potential causes. The diagnosis is supported by significant arterial occlusive disease in the mesenteric vessels, particularly the superior mesenteric artery. Treatment requires revascularization with the primary target being the superior mesenteric artery. Endovascular revascularization with a balloon-expandable covered intraluminal stent is the recommended initial treatment with open repair reserved for select younger patients and those who are not endovascular candidates. Long-term follow-up and surveillance are recommended after revascularization and for asymptomatic patients with severe mesenteric occlusive disease. Patient with recurrent symptoms after revascularization owing to recurrent stenoses should be treated with an endovascular-first approach, similar to the de novo lesion. CONCLUSIONS: These practice guidelines were developed based on the best available evidence. They should help to optimize the care of patients with CMI. Multiple areas for future research were identified.

A model to demonstrate that endotension is a nonvisualized type I endoleak.

OBJECTIVE: Unexplained aneurysm growth despite multimodality imaging after endovascular aneurysm repair is often attributed to endotension. We tested a hypothesis that endotension may be from a type Ia endoleak pressurizing the aneurysm sac, without net forward flow, not visualized on standard angiographic imaging. METHODS: A patient-specific aortic aneurysm phantom was constructed of polyvinyl alcohol using three-dimensional molding techniques. A bifurcated stent graft was implanted, and the phantom was connected to a hemodynamic simulator for testing. Type Ia endoleaks were created using 7F catheters. Three scenarios were studied: complete exclusion (no endoleak), inflow with no sac outflow, and inflow with sac outflow. Imaging with digital subtraction angiography was performed at 48 kVp at 5 frames/s, followed by delayed imaging at 1 frame/min for 30 minutes. RESULTS: With no endoleak, the systemic pressure averaged 113 mm Hg and aneurysm sac pressure averaged 101 mm Hg. With an endoleak present without outflow, the systemic pressure averaged 116 mm Hg, the aneurysm sac pressure averaged 120 mm Hg, and endoleak flow was bidirectional with no net forward flow. With endoleak present with aneurysm sac outflow, the systemic pressure averaged 119 mm Hg, aneurysm sac pressure averaged 105.5 mm Hg, and net endoleak flow into the aneurysm sac was 21 mL/min across the endoleak channel. With digital subtraction imaging, the endoleak with no outflow was noted after >9 minutes of delayed imaging. CONCLUSIONS: In our model, the creation of a type Ia endoleak in the absence of sac outflow resulted in a mean pressure higher than the systemic mean pressure with zero net flow into the aneurysm sac. Consequently, the endoleak could only be visualized with markedly delayed imaging and not with standard contrast digital subtraction angiography like that used in clinical practice. Our findings suggest that endotension may in fact be the result of undetected endoleaks secondary to the limitations of present iodinated contrast imaging modalities.

In vitro hemodynamic model of the arm arteriovenous circulation to study hemodynamics of native arteriovenous fistula and the distal revascularization and interval ligation procedure.

BACKGROUND: Experimental modeling of arteriovenous hemodialysis fistula (AVF) hemodynamics is challenging. Mathematical modeling struggles to accurately represent the capillary bed and venous circulation. In vivo animal models are expensive and labor intensive. We hypothesized that an in vitro, physiologic model of the extremity arteriovenous circulation with provisions for AVF and distal revascularization and interval ligation (DRIL) configurations could be created as a platform for hemodynamic modeling and testing. METHODS: An anatomic, upper extremity arteriovenous model was constructed of tubing focusing on the circulation from the subclavian artery to subclavian vein. Tubing material, length, diameter, and wall thickness were selected to match vessel compliance and morphology. All branch points were constructed at physiologic angles. The venous system and capillary bed were modeled using tubing and one-way valves and compliance chambers. A glycerin/water solution was created to match blood viscosity. The system was connected to a heart simulator. Pressure waveforms and flows were recorded at multiple sites along the model for the native circulation, brachiocephalic AVF configuration, and the AVF with DR without and with IL (DR no IL and DRIL). RESULTS: A preset mean cardiac output of 4.2 L/min from the heart simulator yielded a subclavian artery pressure of 125/55 mm Hg and a brachial artery pressure of 121/54 mm Hg with physiologic arterial waveforms. Mean capillary bed perfusion pressure was 41 mm Hg, and mean venous pressure in the distal brachial vein was 17 mm Hg with physiologic waveforms. AVF configuration resulted in a 15% decrease in distal pressure and a 65% decrease in distal flow to the hand. DR no IL had no change in distal pressure with a 27% increase in distal flow. DRIL resulted in a 3% increase in distal pressure and a 15% increase in distal flow to the hand above that of DR no IL. Flow through the DR bypass decreased from 329 mL/min to 55 mL/min with the addition of IL. Flow through the AVF for both DR no IL and DRIL was preserved. CONCLUSIONS: Through the construction and validation of an in vitro, pulsatile arteriovenous model, the intricate hemodynamics of AVF and treatments for ischemic steal can be studied. DR with or without IL improved distal blood flow in addition to preserving AVF flow. IL decreased the blood flow through the DR bypass itself. The findings of the AVF as a pressure sink and the relative role of IL with DR bypass has allowed this model to provide hemodynamic insight difficult or impossible to obtain in animal or human models. Further study of these phenomena with this model should allow for more effective AVF placement and maturation while personalizing treatment for associated ischemic steal. CLINICAL RELEVANCE: The complications of arteriovenous fistula (AVF)-associated steal with its concurrent surgical treatments have been clinically described but have relatively little published, concrete hemodynamic data. A further understanding of the underlying hemodynamics is necessary to prevent the occurrence of steal and improve treatment when it occurs. Specific objectives are to study the blood flow through an AVF with varying anatomic and physiologic parameters, determine what factors contribute to the development of arterial steal distal to an AVF, and create optimal interventions to treat arterial steal from an AVF when it occurs. The long-term goal is creation of AVF tailored to patient-specific parameters, resulting in higher rates of functional fistulas with decreases in fistula-related complications. The ability to study fluid dynamics using a unique, in vitro, upper extremity pulsatile arteriovenous circulation simulator creates the ideal platform for this work.

Correlation of intravascular ultrasound and computed tomography scan measurements for placement of intravascular ultrasound-guided inferior vena cava filters.

OBJECTIVE: The single puncture intravascular ultrasound (IVUS)-guided bedside placement of inferior vena cava (IVC) filters has been shown to be an effective technique. The major disadvantage of this procedure is a steep learning curve that can lead to an increased risk of filter malposition. In an effort to increase the safety and efficacy of IVUS-guided bedside IVC filter placement, we proposed that preoperative planning could reduce the incidence of IVUS-guided filter malpositions. As a first step, we examined the correlation between preoperative abdominal computed tomography (CT) scan measurements and intraprocedural IVUS derived measurements of vena cava anatomy and its surrounding structures. As a second step, we attempted to determine the safety of this protocol by assessing the incidence of malposition. METHODS: A retrospective review of prospectively collected data was performed on all patients receiving bedside IVUS-guided filters from July 1, 2010 to August 31, 2011. Measurements of the IVC length from the atrial-IVC junction to the midportion of the crossing right renal artery, the lowest renal vein, and iliac vein confluence were obtained prior to IVC filter placement by both CT-based measurement, as well as intraprocedural IVUS pullback lengths. Regression analysis (significant for P < .05) was used to determine the correlation between these imaging modalities. RESULTS: Forty-six patients had adequate CT scans available to perform the analysis and were candidates for bedside IVUS-guided IVC filter placement. All IVUS-guided filters were placed using a single puncture technique with the Cook Celect Filter. This study found there was a close correlation between IVUS and CT derived measurements of the right atrium to right renal artery distance, lowest renal vein distance, and iliac confluence distance. In addition, we found that the IVUS distances from the atrial-IVC junction to the right renal artery and lowest renal vein were statistically similar. Nine patients had 10 vascular anatomic variations, all identified by both IVUS and CT. There were no complications or malpositions of IVC filters using this protocol. CONCLUSIONS: These data suggest that IVUS pullback measurements from the right atrium used in combination with preprocedure CT derived measurements of the distance from the right atrium to the lowest renal vein and iliac vein confluence provide an accurate roadmap for the placement of bedside IVC filters under IVUS guidance. We provide a method for organizing this information in a preplanning document to aid this procedure. We suggest this easily employed technique be more fully utilized to help decrease the incidence of malpositioned filters using single puncture IVUS guidance.

Risk score for unplanned vascular readmissions.

OBJECTIVE: Vascular surgery patients have high readmission rates, and identification of high-risk groups that may be amenable to targeted interventions is an important strategy for readmission prevention. This study aimed to determine predictors of unplanned readmission and develop a risk score for predicting readmissions after vascular surgery. METHODS: The National Surgical Quality Improvement Program database for 2011 was queried for major vascular surgical procedures. The primary end point was unplanned 30-day readmissions. The data were randomly split into two-thirds for development and one-third for validation. Multivariable logistic regression was used to create and validate a point score system to predict unplanned readmissions. RESULTS: Overall, 24,929 patients were included, with 2507 readmissions (10.1%). A point-based scoring system was developed with the use of factors predictive for readmission, including procedure type; discharge destination; race; non-elective presentation; pulmonary, renal, and cardiac comorbidities; diabetes; steroid use; hypoalbuminemia; anemia; venothromboembolism before discharge; graft failure before discharge; and bleeding disorder. The point score stratified patients into 3 groups: low risk (0-3 points) with a readmission rate of 5.4%, moderate risk (4-7 points) with a readmission rate of 8.6%, and high risk (≥ 8 points) with a readmission rate of 16.4%. The model had a C-statistic = 0.67. CONCLUSIONS: Through the use of patient, operative, and predischarge events, this novel vascular surgery-specific readmission score accurately identified patients at high risk for 30-day unplanned readmission. This model could help direct discharge and home health care resources to patients at high risk, ultimately reducing readmissions and improving efficiency.

Predictive multivariate regression to increase the specificity of carotid duplex ultrasound for high-grade stenosis in asymptomatic patients.

BACKGROUND: Carotid duplex ultrasound (CDUS) is commonly used to screen for carotid artery stenosis. Specificities of CDUS criteria however are lower than sensitivities, potentially resulting in false-positive examinations with subsequent unnecessary imaging or surgery. Our objective was to establish a multivariate logistic regression to increase the specificity of CDUS for high-grade (≥70%) stenosis. METHODS: A retrospective review collected CDUS velocities and radiographic measurements from patients who underwent both CDUS and computed tomography angiography (CTA). After stratification with standard CDUS criteria, a logistic regression was created using peak systolic velocity (PSV), end diastolic velocity (EDV), and PSV ratio (PSV of internal carotid artery [ICA]/PSV of common carotid artery [CCA]) as predictor variables. A receiver operating characteristic curve was generated to test the model's predictive ability. A cutoff probability for unequivocal high-grade stenosis was chosen based on optimal specificity. The regression model was applied to patients with equivocal high-grade stenosis. Probabilities for detection of high-grade stenosis were calculated. Descriptive statistics were generated to quantify the accuracy of the model. RESULTS: A total of 244 vessels were included. Standardized velocity criteria for ≥70% stenosis yielded a sensitivity of 90.6% (95% confidence interval [CI], 82.3-95.6%), specificity of 63.5% (95% CI, 55.4-70.5%), positive predictive value (PPV) of 57.0% (95% CI, 48.8-65.5%), and negative predictive value (NPV) of 92.7% (95% CI, 85.8-96.5%). Regression analysis produced a model for predicting the probability of high-grade stenosis defined as probability = logit(-1) (-4.97 + [0.00938 × PSV] + [0.0135 × EDV] + [0.103 × PSV ICA/CCA ratio]). A cutoff probability of 0.65 for high-grade stenosis yielded a sensitivity of 54.7% (95% CI, 43.9-65.0%), specificity of 94.3% (95% CI, 89.3-97.2%), PPV of 83.9% (95% CI, 71.6-91.9%), and NPV of 79.3% (95% CI, 72.8-84.5%). A cutoff PSV of 400 cm/sec was chosen for unequivocal stenosis of ≥70%. A total of 94 patients were found to meet criteria for high-grade stenosis (PSV ≥ 230 cm/sec) but fall short of criteria for unequivocal high-grade stenosis (PSV < 400 cm/sec). Application of the regression model resulted in identification of 15 patients with probability ≥0.65 for high-grade stenosis and 79 patients with probability <0.65. This resulted in a 16% potential reduction in CTA scans. CONCLUSIONS: Our regression model provides increased specificity of CDUS for high-grade stenosis in patients who have met initial highly sensitive screening criteria. Application of this model may limit the need for additional imaging and increase the threshold for operative intervention in asymptomatic patients with equivocal high-grade carotid stenosis.

CT angiography-derived duplex ultrasound velocity criteria in patients with carotid artery stenosis.

BACKGROUND: Validation of carotid duplex ultrasound velocity criteria (CDUS VC) to grade the severity of extracranial carotid artery stenosis has traditionally been based on conventional angiography measurements. In the last decade, computed tomographic angiography (CTA) has largely replaced conventional arch and carotid arteriography (CA) for diagnostic purposes. Given the low number of CA being performed, it is impractical to expect noninvasive vascular laboratories to be validated using this modality. CDUS VC have not been developed with the use of CTA-derived measurements. The objective was to determine optimal CDUS VC from CTA-derived measurements with the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method for 50% and 80% stenosis. METHODS: A retrospective review of all patients who underwent CDUS and CTA from 2000 to 2009 was performed. Vessel diameters were measured on CTA, and corresponding CDUS velocities were recorded. Percent stenosis was calculated using the NASCET method. Receiver operating characteristic (ROC) curves were generated for internal carotid artery (ICA) peak systolic velocity (PSV), ICA end diastolic velocity (EDV), and ICA PSV to common carotid artery PSV ratio (PSVR) for 50% and 80% stenosis. Velocity cut points were determined with equal weighting of sensitivity and specificity. RESULTS: A total of 575 vessels were analyzed to create the ROC curves. A 50% stenosis analysis yielded ideal cut points for PSV, EDV, and PSVR of 130 cm/sec, 42 cm/sec, and 1.75. An 80% stenosis analysis yielded ideal cut points for PSV, EDV, and PSVR of 297 cm/sec, 84 cm/sec, and 3.06. CONCLUSIONS: CTA-derived CDUS VC appeared to be reliable in defining 50% and 80% stenosis in patients with carotid artery stenosis. Although CDUS VC defined in this study were different from many of the previously published VC for the same percent stenosis, there were many similarities to those reported by the Society of Radiologists in Ultrasound consensus conference. We feel that CTA should be the gold standard imaging technique for validating CDUS VC.

Bilateral internal carotid artery hypoplasia presenting with watershed territory infarcts.

Internal carotid artery hypoplasia is a rare vascular anomaly that can lead to various neurological symptoms due to altered cerebral blood flow. We present a case of a 36 years old female who presented to us with forgetfulness and right sided weakness. She was ultimately diagnosed with bilateral internal carotid artery hypoplasia through imaging studies. This case highlights the importance of considering vascular anomalies in patients presenting with neurological symptoms and the significance of comprehensive diagnostic evaluation for appropriate management.

Multidisciplinary collaboration as a sustainable research model for device development.

The concurrent problems of research sustainability and decreased clinician involvement with medical device development can be jointly addressed through a novel, multidisciplinary solution. The University of Rochester Cardiovascular Device Design Program is a sustainable program in medical device design supported through a collaboration between the Schools of Medicine and Engineering. This article provides a detailed description of the motivation for starting the program, the current structure of the program, the methods of financial sustainability, and the direct impact it intends to have on the national vascular surgery community. The further expansion of this program and encouragement for development of similar programs throughout the country aims to address many of our current challenges in both research funding and device development education.

Resident involvement is associated with worse outcomes after major lower extremity amputation.

BACKGROUND: Despite the recent major changes in vascular and general surgery training, there has been a paucity of literature examining the effect of these changes on training and surgical outcomes. Amputations represent a common cross-section in core competencies for general surgery and vascular surgery trainees. This study evaluates the effect of trainee participation on outcomes after above-knee and below-knee amputations. METHODS: The American College of Surgeons-National Surgical Quality Improvement Program (NSQIP) database (2005 to 2010) was queried using Current Procedural Terminology codes (American Medical Association, Chicago, Ill) for below-knee amputation (27880, 27882) and above knee-amputation (27590, 27592). Resident involvement was defined using the NSQIP variable and was narrowed to postgraduate year 1 to 5. Variables associated with resident involvement were identified, and mortality, morbidity, intraoperative transfusion, and operative time (75th percentile vs the bottom three quartiles) were evaluated as distinct categoric end points in logistic regression. Included in the model were variables with a P value <.1 on χ(2) or independent t-test, as appropriate. Significance was defined at P < .05. RESULTS: Residents were involved in 6587 of 11,038 amputations (62%). After adjustment for preoperative and intraoperative factors on logistic regression, there was a significant increase in major morbidity (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.14-1.42; P < .001), intraoperative transfusion (OR, 1.78; 95% CI, 1.50-2.11; P < .001), and operative time (OR, 1.64 95% CI, 1.46-1.84; P < .001) in resident cases. CONCLUSIONS: Resident involvement was associated with increased odds of major morbidity after amputation and also with increased operative time and risk for intraoperative transfusions.

Cross-sectional area for the calculation of carotid artery stenosis on computed tomographic angiography.

OBJECTIVE: The use of cross-sectional area (CSA) measurements obtained from computed tomographic angiography (CTA) for the calculation of carotid artery stenosis has been suggested but not yet validated in a large population. The objective of this study was to determine whether CTA-derived CSA measurements were able to predict carotid stenosis with a level of confidence similar to CTA-derived diameter measurements, using Strandness criteria applied to carotid duplex ultrasound (CDUS) as a surrogate for true stenosis. METHODS: A retrospective review was conducted to identify patients who underwent both CDUS and CTA between 2000 and 2009. Percent stenosis was calculated using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) formula with diameter measurements and again with CSA measurements. A nonparametric correlation coefficient was calculated to detect correlation between the two groups. Two-dimensional receiver-operating characteristic curves with corresponding area under the curve (AUC) statistics were generated for >50% stenosis and >80% stenosis. Three-dimensional receiver-operating characteristic plots with corresponding volume under the surface (VUS) statistics were generated to measure the comparative accuracy of diameter-based and CSA-based stenosis for <50%, 50%-79%, and >80% stenosis. RESULTS: A total of 575 vessels in 313 patients were included in the study. Spearman's correlation coefficient between diameter and CSA-derived stenosis was ρ = 0.938 (95% confidence interval [CI], 0.927-0.947; P < .0001). For diameter-derived stenosis, AUC was 0.905 (95% CI, 0.878-0.932; P < .0001) for >50% stenosis and 0.950 (95% CI, 0.928-0.972; P < .0001) for 80%-99% stenosis. For CSA-derived percent stenosis, the AUC was 0.908 (95% CI, 0.882-0.935; P < .0001) for >50% stenosis and 0.935 (95% CI, 0.908-0.961; P < .0001) for 80%-99%. The nonparametric estimate for VUS in the diameter-based stenosis group was 0.761, whereas in the CSA-based group, the VUS was 0.735. The difference between VUS was 0.026 (95% CI, -0.022 and 0.077; P = .318). CONCLUSIONS: These data support the use of CTA as an accurate method of calculating carotid artery stenosis based on agreement with Strandness criteria applied to CDUS velocities. When additional imaging beyond CDUS is necessary, we report no significant difference between diameter and CSA measurements obtained from CTA for preoperative evaluation of carotid disease.

Chronic mesenteric ischemia in a 26-year-old man: multivessel median arcuate ligament compression syndrome.

BACKGROUND: Chronic mesenteric ischemia (CMI) is a rare diagnosis for patients in their third decade of life. Other conditions can mimic the signs and symptoms of CMI, including median arcuate ligament syndrome (MALS), primary arteritides, and congenital anomalies. Here, we present the case of a 26-year-old man who presented with CMI and multivessel mesenteric occlusive disease. METHODS: A 26-year-old man presented with a 6-month history of 40-pound weight loss, postprandial abdominal pain, and food fear. His physical examination showed a scaphoid abdomen with no tenderness. Findings from laboratory evaluation were normal. Computed tomography angiogram revealed celiac artery (CA) occlusion and >80% superior mesenteric artery (SMA) stenosis, with a large marginal artery of Drummond supplying collateral circulation. RESULTS: A retroperitoneal exposure of the perivisceral aorta was performed. Surgical exposure revealed compression of both CA and SMA by the MAL. The total distance of caudal arterial displacement was >3 cm. Both the CA and SMA were chronically stenotic/occluded secondary to this compression. After division of the MAL, a retrograde aortoceliac and aortomesenteric bypass was performed for mesenteric revascularization. The patient recovered uneventfully and was discharged home on the third day after surgery tolerating a full diet. CONCLUSIONS: MALS is a pathologic entity that can affect more than the CA. This case demonstrates multivessel, mesenteric arterial insufficiency secondary to MALS sufficient to promote IMA collateralization of the SMA circulation. In young patients with CMI, multivessel MALS must be considered. In addition to MAL release, arterial revascularization may be necessary owing to stenoses from chronic compression.

Standardization is superior to traditional methods of teaching open vascular simulation.

OBJECTIVES: Standardizing surgical skills teaching has been proposed as a method to rapidly attain technical competence. This study compared acquisition of vascular skills by standardized vs traditional teaching methods. METHODS: The study randomized 18 first-year surgical residents to a standardized or traditional group. Participants were taught technical aspects of vascular anastomosis using femoral anastomosis simulation (Limbs & Things, Savannah, Ga), supplemented with factual information. One expert instructor taught a standardized anastomosis technique using the same method each time to one group over four sessions, while, similar to current vascular training, four different expert instructors each taught one session to the other (traditional) group. Knowledge and technical skill were assessed at study completion by an independent vascular expert using Objective Structured Assessment of Technical Skill (OSATS) performance metrics. Participants also provided a written evaluation of the study experience. RESULTS: The standardized group had significantly higher mean overall technical (95.7% vs 75.8%; P = .038) and global skill scores (83.4% vs 67%; P = .006). Tissue handling, efficiency of motion, overall technical skill, and flow of operation were rated significantly higher in the standardized group (mean range, 88%-96% vs 67.6%-77.6%; P < .05). The standardized group trended to better cognitive knowledge (mean, 68.8% vs 60.7%; P = .182), creation of a secure knot at the toe of the anastomosis, fashioning an appropriate arteriotomy, better double-ended suture placement at the heel of the anastomosis (100% vs 62.7%; P = .07), and accurate suture placement (70% vs 25%; P = .153). Seventy-two percent of participant evaluations suggested a preference for a standardized approach. CONCLUSIONS: This study demonstrates the feasibility of open vascular simulation to assess the effect of differing teaching methods on performance outcome. Findings from this report suggest that for simulation training, standardized may be more effective than traditional methods of teaching. Transferability of simulator-acquired skills to the clinical setting will be required before open simulation can be unequivocally recommended as a major component of resident technical skill training.

Postprocedural peak systolic blood flow measurements correlate with the need for stent reintervention at 12 months.

PURPOSE: Duplex surveillance of arterial stents has focused on detecting in-stent restenosis. Although velocity is commonly reported, that differs from blood flow, and patency of arterial prostheses is flow-dependent. Preliminary evaluation was performed to determine if postprocedure peak systolic blood flow (PSF) through stents correlates with rate of repeat intervention at 12 months. MATERIALS AND METHODS: Retrospective review of consecutive patients undergoing arterial stent placement was performed. Demographics, comorbidities, stent size, postprocedure duplex information, and repeat intervention rates were recorded. PSF was calculated by using peak systolic velocity (PSV) and stent dimensions. RESULTS: Consecutive stents (N = 35) were placed in 27 patients (mean age, 72.6 y ± 14). Twenty stents were free from repeat intervention (FR) and 15 required repeat intervention (RR) at 12 months. There was a significant difference between FR and RR groups with respect to initial in-stent PSV and PSF (92.5 cm/s for FR vs 43.7 cm/s for RR [P < .002]; 1,918 mL/min for FR vs 722 mL/min for RR [P < .0001]). PSF showed sensitivity, specificity, and accuracy rates of 92%, 82%, and 86.2%, respectively, for predicting repeat intervention, versus 83%, 71%, and 76% for PSV. Receiver operating characteristic curve analysis showed a greater area under the curve for PSF versus PSV (0.965 vs 0.859). CONCLUSIONS: PSF from an initial postprocedure duplex study accurately correlates with need for repeat stent intervention at 12 months. PSV had a lower sensitivity, specificity, and accuracy. This preliminary finding must be confirmed by prospective studies in individual vascular beds and larger patient populations. A new approach to stent surveillance is suggested.

Classification of proximal endovenous closure levels and treatment algorithm.

OBJECTIVES: Endovenous closure is a common method to treat saphenous vein incompetence. Despite attempts to prevent it, some patients have extension of thrombus above the ideal site of closure immediately below the epigastric vein. We have developed a classification system for the level of saphenous vein closure to guide further therapy after endovenous treatment. METHODS: A six-tier classification system was developed, based on thrombus proximity to the epigastric or femoral vein, and an algorithm for treatment, based on level of closure was applied to all patients. RESULTS: Five hundred consecutive patients underwent radio-frequency ablation of the saphenous vein; it was successfully closed in 498 (99.6%) patients. Thirteen patients (2.6%) experienced thrombus bulging into the femoral vein or adherent to its wall, which was treated with anticoagulation. All of these patients had thrombus retraction to the level of the saphenofemoral junction (SFJ) in an average of 16 days with concurrent anticoagulation. No femoral deep venous thrombosis (DVT) occurred in the series. There was a significantly higher rate of proximal thrombus extension in those patients with a history of DVT and those with a great saphenous vein (GSV) diameter of >8 mm (P < .02). CONCLUSIONS: A classification system for saphenous endovenous closure which extends above the epigastric vein has been helpful in guiding management. A GSV diameter at the SFJ of >8 mm and a history of DVT results in significantly higher rates of proximal thrombus extension into the femoral vein. A short course of LMWH, until clot retracts back into the saphenous vein, is therapeutic. Management of the patients with thrombus flush with the femoral vein wall still needs to be defined, but the outcome from these patients is generally benign.

Thrombolysis for acute lower extremity deep venous thrombosis in a tertiary care setting.

BACKGROUND: In 2008, the Surgeon General made a Call to Action for the prevention of deep venous thrombosis (DVT), and for the first time, the 2008 American College of Chest Physicians guidelines for treatment of acute lower extremity DVT (ALE DVT) were revised to include thrombolysis as a grade 2B recommendation. Catheter-directed thrombolysis (CDT) therapy for patients with ALE DVT without contraindications can result in more complete clot dissolution than anticoagulation alone and may prevent the long-term sequelae of DVT. We sought to determine the percentage of inpatients with ALE DVT at a tertiary medical center who were candidates for CDT therapy and whether these patients were appropriately offered such treatment. METHODS: A hospital administrative database search from a tertiary medical center between January 2007 and December 2007 revealed 667 patient admissions associated with a diagnosis of DVT by International Classification of Diseases, Ninth Revision diagnosis codes (451-451.99, 453-453.99). Computerized hospital records were then searched for information regarding medical history, comorbidities, contraindications to thrombolysis, symptoms, imaging findings, and treatment. RESULTS: Of the 667 patient admissions, 157 (24%) had ALE DVT, 31% had upper extremity DVT, 17% carried an old diagnosis DVT, and 28% had venous thromboses in other vessels. Of those 157 patients with ALE DVT, 60 (38%) had proximal iliofemoral or extensive femoral DVT that would be candidates for thrombolysis. Of the 60 patients, only 10 (17%) had no major contraindication thrombolysis. Of these, one was offered CDT but refused treatment, four did not receive consults for thrombolysis; five (9%) were offered CDT and were treated. However, of these 60 patients, 50 (83%) patients had severe illness and major and often multiple contraindications to thrombolysis. CONCLUSION: Although the majority of patients identified in the 2007 inpatient database with ALE DVT and an absence of contraindications to thrombolysis were appropriately offered CDT therapy, patients in such a tertiary inpatient setting typically have severe medical comorbidities that precluded the use of thrombolysis. Future studies assessing the expanding role of CDT in patients with ALE DVT should focus on outpatient settings or nontertiary care hospitals, where patients are likely to have fewer contraindications to thrombolytic therapy.

Aneurysmectomy with arterial reconstruction of renal artery aneurysms in the endovascular era: a safe, effective treatment for both aneurysm and associated hypertension.

BACKGROUND: Renal artery aneurysms (RAAs) represent a rare vascular pathology with an estimated incidence of <1%. Although an endovascular approach is being increasingly used to treat RAAs, we hypothesized that open surgical repair of RAA, specifically via aneurysmectomy with arterial reconstruction (AAR), is a safe, effective treatment, particularly for those with complex aneurysm anatomy. METHODS: A review was performed of all patients with RAA, identified by ICD-9 codes, from January 2003 to December 2008 seen at a tertiary care medical center. Data were collected regarding patient demographics, aneurysm characteristics, surgical repair, and outcomes, as well as follow-up care. RESULTS: A total of 14 patients (10 women and 4 men; mean age, 48+/-19 years) were included, representing 15 aneurysms. Ten aneurysms underwent open repair via AAR and five were followed nonoperatively. Mean RAA size was larger for those undergoing repair (2.12 cm vs. 1.62 cm, p=0.037). Seven RAAs were repaired in situ with either patch angioplasty or primary repair; three required ex vivo reconstruction; and none underwent bypass. Average operative time was similar for repair type, with a higher blood loss with ex vivo repair. Median length of stay was 5 days (range, 4 to 14 days). Operative repair had no effect on mean systolic blood pressure or GFR. This repair, however, resulted in lower medication requirement for those with concurrent hypertension (2.7 pre vs. 1.6 post, p=0.03). There was a trend toward shorter time until oral intake for retroperitoneal approach compared with transperitoneal. Mean follow-up time was 11.6 months (range, 3 to 30 months). No incidences of rupture, death, nephrectomy, or renal failure occurred in the operative group. CONCLUSION: In the era of endovascular repairs for RAAs, open repair, specifically via AAR, of RAAs remains a safe treatment with low associated morbidity. RAA repair resulted in a reduction in medications for those with associated hypertension. Open repair of RAAs should be the primary treatment modality for complex RAA, with specific consideration given to those with associated hypertension.

ACR Appropriateness Criteria® Suspected Upper Extremity Deep Vein Thrombosis.

This publication includes the appropriate imaging modalities to assess suspected deep vein thrombosis in the upper extremities. Ultrasound duplex Doppler is the most appropriate imaging modality to assess upper-extremity deep vein thrombosis. It is a noninvasive test, which can be performed at the bedside and used for serial evaluations. Ultrasound can also directly identify thrombus by visualizing echogenic material in the vein and by lack of compression of the vein walls from manual external pressure. It can indirectly identify thrombus from altered blood-flow patterns. It is most appropriate in the evaluation of veins peripheral to the brachiocephalic vein. CT venography and MR venography are not first-line imaging tests, but are appropriate to assess the central venous structures, or to assess the full range of venous structures from the hand to the right atrium. Catheter venography is appropriate if therapy is required. Radionuclide venography and chest radiography are usually not appropriate to assess upper-extremity deep vein thrombosis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Thoracic Outlet Syndrome.

Thoracic outlet syndrome (TOS) is the clinical entity that occurs with compression of the brachial plexus, subclavian artery, and/or subclavian vein at the superior thoracic outlet. Compression of each of these structures results in characteristic symptoms divided into three variants: neurogenic TOS, venous TOS, and arterial TOS, each arising from the specific structure that is compressed. The constellation of symptoms in each patient may vary, and patients may have more than one symptom simultaneously. Understanding the various anatomic spaces, causes of narrowing, and resulting neurovascular changes is important in choosing and interpreting radiological imaging performed to help diagnose TOS and plan for intervention. This publication has separated imaging appropriateness based on neurogenic, venous, or arterial symptoms, acknowledging that some patients may present with combined symptoms that may require more than one study to fully resolve. Additionally, in the postoperative setting, new symptoms may arise altering the need for specific imaging as compared to preoperative evaluation. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Angled guidewire delivery of aortic endovascular prostheses for angulated landing zones.

We present a case of a 90-year-old male with suprarenal, infrarenal, and bilateral iliac aneurysms with significant interval enlargement treated with an endovascular graft. Due to severe infrarenal neck angulation, a type 1a endoleak was encountered, which was successfully treated with an aortic cuff. A novel technique of cuff deployment over an angled guidewire to accommodate the aortic angulation was used. This represents the first report in the literature of using this technique to deal with difficult, angulated landing zones.