Arteriovenous Fistula Surveillance Using Tomographic 3D Ultrasound.

OBJECTIVE: A well functioning arteriovenous fistula (AVF) is essential for haemodialysis. Despite regular duplex ultrasound (DUS) a significant number of AVFs fail. Tomographic 3D ultrasound (tUS) creates a 3D image of the AVF that can be interpreted by the clinician. DUS, tUS, and fistulograms were compared for the identification and measurement of flow limiting stenosis. METHODS: Patients with AVF dysfunction on routine Transonic surveillance, defined as (1) > 15% reduction in flow on two consecutive occasions, (2) > 30% reduction in flow on one occasion, (3) flow of < 600 mL/sec, (4) presence of recirculation, underwent DUS. AVF tUS imaging was performed prior to fistulography. All fistulograms were reported by the same consultant radiologist and tUS images by the same vascular scientist blinded to the fistulogram results. Maximum diameter reduction in all stenoses were measured using all three imaging techniques. RESULTS: In 97 patients with 101 stenoses, the mean (± standard deviation [SD]) severity of stenosis was 63.0 ± 13.9%, 65.0 ± 11.6%, and 64.8 ± 11.7% for the fistulograms, DUS, and tUS respectively. The mean (± SD) time between ultrasound and fistulography imaging was 15.0 ± 14.5 days. Assuming the fistulogram as the "gold standard", Bland-Altman agreement for DUS was -1.9 ± 15.5% (limit of agreement [LOA] -32.2 - 28.4) compared with -1.7 ± 15.4% (LOA -31.9 - 28.4) for tUS. Median (± interquartile range) time to complete the investigation was 09:00 ± 03:19 minutes for DUS and 03:13 ± 01:56 minutes for tUS (p < .001). CONCLUSION: DUS and tUS were equally accurate at detecting AVF complications but tUS investigation requires less skill and was significantly quicker than DUS.

Deep vein thrombosis in hospitalized patients with coronavirus disease 2019.

OBJECTIVE: The pandemic of coronavirus disease 2019 (COVID-19) has caused devastating morbidity and mortality worldwide. In particular, thromboembolic complications have emerged as a key threat for patients with COVID-19. We assessed our experience with deep vein thrombosis (DVT) in patients with COVID-19. METHODS: We performed a retrospective analysis of all patients with COVID-19 who had undergone upper or lower extremity venous duplex ultrasonography at an academic health system in New York City from March 3, 2020 to April 12, 2020 with follow-up through May 12, 2020. A cohort of hospitalized patients without COVID-19 (non-COVID-19) who had undergone venous duplex ultrasonography from December 1, 2019 to December 31, 2019 was used for comparison. The primary outcome was DVT. The secondary outcomes included pulmonary embolism, in-hospital mortality, admission to the intensive care unit, and antithrombotic therapy. Multivariable logistic regression was performed to identify the risk factors for DVT and mortality. RESULTS: Of 443 patients (COVID-19, n = 188; and non-COVID-19, n = 255) who had undergone venous duplex ultrasonography, the COVID-19 cohort had had a greater incidence of DVT (31% vs 19%; P = .005) than had the non-COVID-19 cohort. The incidence of pulmonary embolism was not significantly different statistically between the COVID-19 and non-COVID-19 cohorts (8% vs 4%; P = .105). The DVT location in the COVID-19 group was more often distal (63% vs 29%; P < .001) and bilateral (15% vs 4%; P < .001). The duplex ultrasound findings had a significant impact on the antithrombotic plan; 42 patients (72%) with COVID-19 in the DVT group had their therapy escalated and 49 (38%) and 3 (2%) had their therapy escalated and deescalated in the non-DVT group, respectively (P < .001). Within the COVID-19 cohort, the D-dimer level was significantly greater in the DVT group at admission (2746 ng/mL vs 1481 ng/mL; P = .004) and at the duplex examination (6068 ng/mL vs 3049 ng/mL; P < .01). On multivariable analysis, male sex (odds ratio [OR], 2.27; 95% confidence interval [CI], 1.06-4.87; P = .035), intensive care unit admission (OR, 3.42; 95% CI, 1.02-11.44; P = .046), and extracorporeal membrane oxygenation (OR, 5.5; 95% CI, 1.01-30.13; P = .049) were independently associated with DVT. CONCLUSIONS: Given the high incidence of venous thromboembolic events in this population, we support the decision to empirically initiate therapeutic anticoagulation for patients with a low bleeding risk and severe COVID-19 infection. Duplex ultrasonography should be reserved for patients with a high clinical suspicion of venous thromboembolism for whom anticoagulation therapy could result in life-threatening consequences. Further study of patients with COVID-19 is warranted to elucidate the etiology of vascular thromboembolic events and guide the prophylactic and therapeutic interventions for these patients.

Clinical and laboratory characteristics of patients with novel coronavirus disease-2019 infection and deep venous thrombosis.

OBJECTIVE: Early reports suggest that patients with novel coronavirus disease-2019 (COVID-19) infection carry a significant risk of altered coagulation with an increased risk for venous thromboembolic events. This report investigates the relationship of significant COVID-19 infection and deep venous thrombosis (DVT) as reflected in the patient clinical and laboratory characteristics. METHODS: We reviewed the demographics, clinical presentation, laboratory and radiologic evaluations, results of venous duplex imaging and mortality of COVID-19-positive patients (18-89 years) admitted to the Indiana University Academic Health Center. Using oxygen saturation, radiologic findings, and need for advanced respiratory therapies, patients were classified into mild, moderate, or severe categories of COVID-19 infection. A descriptive analysis was performed using univariate and bivariate Fisher's exact and Wilcoxon rank-sum tests to examine the distribution of patient characteristics and compare the DVT outcomes. A multivariable logistic regression model was used to estimate the adjusted odds ratio of experiencing DVT and a receiver operating curve analysis to identify the optimal cutoff for d-dimer to predict DVT in this COVID-19 cohort. Time to the diagnosis of DVT from admission was analyzed using log-rank test and Kaplan-Meier plots. RESULTS: Our study included 71 unique COVID-19-positive patients (mean age, 61 years) categorized as having 3% mild, 14% moderate, and 83% severe infection and evaluated with 107 venous duplex studies. DVT was identified in 47.8% of patients (37% of examinations) at an average of 5.9 days after admission. Patients with DVT were predominantly male (67%; P = .032) with proximal venous involvement (29% upper and 39% in the lower extremities with 55% of the latter demonstrating bilateral involvement). Patients with DVT had a significantly higher mean d-dimer of 5447 ± 7032 ng/mL (P = .0101), and alkaline phosphatase of 110 IU/L (P = .0095) than those without DVT. On multivariable analysis, elevated d-dimer (P = .038) and alkaline phosphatase (P = .021) were associated with risk for DVT, whereas age, sex, elevated C-reactive protein, and ferritin levels were not. A receiver operating curve analysis suggests an optimal d-dimer value of 2450 ng/mL cutoff with 70% sensitivity, 59.5% specificity, and 61% positive predictive value, and 68.8% negative predictive value. CONCLUSIONS: This study suggests that males with severe COVID-19 infection requiring hospitalization are at highest risk for developing DVT. Elevated d-dimers and alkaline phosphatase along with our multivariable model can alert the clinician to the increased risk of DVT requiring early evaluation and aggressive treatment.

[Comparative 3-year results of phlebectomy and thermal ablation for lower limb varicose veins]. / Sravnitel'nye trekhletnie rezul'taty flebéktomii i termoablatsii pri varikoznoi bolezni nizhnikh konechnostei.

OBJECTIVE: The study was aimed at comparing clinical and ultrasonographic results during 3 years of postoperative follow up of patients presenting with lower limb varicose veins (LLVV) and subjected to either surgical or thermal-ablation procedures for removal of pathological reflux along the great saphenous vein (GSV) within the femur The study included a total of 185 patients with clinical class C2-3 LLVV in the system of the GSV. The patients were divided into three groups: Group One consisted of 63 patients subjected to short stripping of the GSV trunk + treatment of the perforant veins (66.7%); Group Two comprised 61 patients undergoing endovenous laser coagulation (EVLC) of the GSV trunk + EVLC of the perforant veins (73.7%); Group Three was composed of 61 patients undergoing radiofrequency ablation of the GSV trunk + ELVC of the perforant veins (70.4%). Complaints were dynamically assessed by the VCSS scale with ultrasonographic duplex scanning. It was revealed that pathological reflux along the GSV trunk on the crus at 1, 2 and 3 years of follow up was registered: in Group One in 33.3, 36.3 and 39.1% of cases, respectively; in Group Two in 15, 14.2 and 25% of cases, respectively; and in Group Three - in 11, 18.1 and 23.8% of cases, respectively. Group One patients at 1 year were found to have developed vertical refluxes emerging on the femur along the GSV tributaries (22.1% of cases), the presence of horizontal refluxes along newly-formed perforant veins (44.4% of cases). The diameter of the GSV trunk on the crus statistically significantly increased with years in all groups. The average diameter of the perforant veins increased at the same time periods of follow up. Alterations of venous haemodynamics revealed on ultrasonographic examination were accompanied by varicose syndrome but exerted no significant effect on subjective symptomatology in patients during 3 years of follow up. The obtained findings are indicative of progression of LLVV in part of surgically treated patients, which requires dynamic follow up and carrying out systemic pharmacotherapy.

Screening of familial hypercholesterolemia among patients in age under 40 years old exposed by duplex scanning of carotid arteries, by the local registry data.

AIM: To identify patients with probable FH among Duplex-2013 registry patients under the age of 40 years, to analyze their lipid spectrum and duplex carotid artery data, to evaluate the changes of their lipid spectrum parameters. MATERIALS AND METHODS: The Duplex-2013 registry database was used for this study (n=2550). Patients under the age of 40 years were selected for follow-up analysis (n=192). RESULTS: 20 of them were selected on the basis of Simon Broome criteria as patients with possible FH. The FH group (n=20) and the control group (n=172) had significant differences in age (35.1 ± 4.01 vs. 32.62 ± 5.29, p=0.044), male gender (18 of 20 (90%) vs 92 of 172 (53%), p=0.003), TC (7.64 ± 0.63 vs 5.34 ± 0.91, p=0.0001) and LDL-C cholesterol (5.45 ± 0.62 vs 3.28 ± 0.78, p=0.00001). When comparing the groups by the combined criterion of atherosclerosis (IMT > 1.0 mm and / or atherosclerotic plaque in the carotid artery >20%), it was noted that signs of carotid atherosclerosis were more often recorded in the FH group compared with the control group (40% vs 26%). Repeated laboratory studies of TC and LDL-C in the FH group after 2.5 years showed their significant dynamics (7.64 ± 0.63 vs 6.03 ± 1.04, p=0.007, 5.45 ± 0.63 vs 3.84 ± 1.24, p=0.035). CONCLUSION: The frequency of detection of FH in the cohort study was 1:10 (11% of all patients). Thus, patients referred for duplex scanning of carotid arteries can be a potential target for screening for FH.

Syncope workup: Greater yield in select trauma population.

BACKGROUND: There is great variation in practice regarding the assessment of trauma patients who present with syncope. The purpose of this study was to determine the yield of screening studies (electrocardiogram, echocardiogram, and carotid duplex) and define characteristics to identify groups that may benefit from these investigations. METHODS: We conducted a retrospective cohort study of all trauma patients from 2003 to 2015 who received a carotid duplex as part of a syncope evaluation at our urban Level 1 Trauma Center. Demographics, clinical findings as well as interventions undertaken (ie: placement of defibrillators/pacemakers) as a result of the syncope evaluation were collected. Data analysis was performed with STATA 14 and relationships between comorbidities, positive findings and interventions were assessed. Significance was assumed for p < 0.05. RESULTS: 736 trauma patients were included in the study. The most common mechanism of injury was fall (592, 82%). A history of congestive heart failure (CHF) and/or coronary artery disease (CAD) and age ≥ 65 were significantly associated with abnormal ECG and ECHO findings, but not with severe carotid stenosis. Elevated Injury Severity Scale (ISS) was significantly associated with an abnormal ECHO on both univariate and multivariate analysis. An abnormal ECG was predictive of an abnormal ECHO (p = 0.02). Ten patients (1.4%) underwent placement of a defibrillator and/or pacemaker, all of whom reported having CHF. Only 11 patients (1.7%) had severe carotid stenosis (>70%) requiring intervention. CONCLUSION: The screening studies used in a syncope evaluation have low yield in the general trauma population. Carotid duplex should not be routinely performed. Cardiac evaluation should be tailored to individuals with cardiac comorbidities, older age and elevated ISS. An ECG should be used as initial screening in this patient cohort.

Characteristics of etiological diagnostic workup across the past 10 years in patients with spontaneous intracerebral hemorrhage in a large general hospital.

OBJECTIVE: A swift and accurate diagnosis of etiology would lay the foundation of targeted management for patients with spontaneous intracerebral hemorrhage (SICH). It is unclear what the status of diagnostic workup related to etiology is in Chinese hospitals which treat the majority of the hemorrhagic patients in the world. We aim to demonstrate characteristics on diagnostic workup implemented routinely in both departments of Neurology and Neurosurgery in patients with SICH. METHODS: We enrolled patients with SICH from March 2002 to December 2011 from Chengdu stroke registry. Data on diagnostic workup were extracted. RESULTS: A total of 2264 patients diagnosed as SICH with rapid neuroimaging (computed tomography (CT) or magnetic resonance imaging (MRI)) scan were included. Patients in the department of Neurosurgery had a lower median Glasgow Coma Scale (GCS) score and a longer median length of stay. They had a significantly lower proportion of hyperlipidemia and heart disease, but a higher proportion of hypertension, alcohol consumption and history of stroke (all p < 0.05). Following diagnostic workups were more frequently undertaken in the Neurological Department than in the neurosurgical Department: digital subtraction angiography (DSA), plain CT, plain MRI, carotid duplex ultrasound (all p < 0.001). However, computed tomography angiography (CTA), contrast-enhanced MRI, and brain biopsy (all p < 0.001) were implemented more in the Neurosurgical Department. While no difference in the proportion of magnetic resonance angiography (MRA) was found between the two departments, the intracranial vascular imaging (workup contains at least one of CTA, MRA and DSA) was performed more frequently in the Department of Neurosurgery (29.8% vs. 9.1%, p < 0.001). The independent predictors contribute to the implementation of vascular examinations were gender, age, GCS score on admission, department of patients admitted in and the year patients were hospitalized in (all p < 0.05). CONCLUSIONS: Younger patients, females, with severe stroke onset (evaluated by GCS score), admitted in Department of Neurosurgery and hospitalized in recent years had undertaken more examinations on intracranial vascular. It is an urgency to explore a practical scheme of diagnostic workup for the etiology of SICH.

[Ways to improve diagnosis and surgical treatment for pathology of brachiocephalic arteries].

UNLABELLED: Over 2010-2013 we anonymously interrogated a total of 397 therapeutists of municipal polyclinics of six regions of Russia (Chelyabinsk, Kurgan, Sverdlovsk, Orenburg, and Saratov Regions and the Republic of Bashkortostan), studying their awareness of the indications and AIM: of ultrasound examination of brachiocephalic arteries (US BCA) in patients presenting with arterial hypertension (AH) and revealing the physicians' attitude to carrying out surgical prevention of stroke in hypertensive patients. As the indications for USS BCA 35 (8.82%) of physicians reported symptoms of local cerebrovascular lesions, mentioning: "complaints of unilateral weakness in the extremities" (n=18), "complaints of speech impairments disorders" (n=2), "complaints of loss of fields of vision" (n=4), "endured TIA" (n=11). A total of 261 (65.74%) respondents considered the grounds for US BCA to be as non-specific cerebrovascular symptoms (isolated dizziness, headache, disequilibrium, syncope). 242 (60.96%) physicians with the purpose of examining asymptomatic hypertensive patients mentioned the type and character of a vascular lesion: 16 (4.03%) - "determining the intima media thickness"; (22 (5.4%) - "an atherosclerotic plaque"; 100 (25.18%) - "arterial stenoses/occlusions". 155 (39.04%) interrogated physicians failed to determine the AIM: of ultrasonic duplex scanning of major arteries of the head. 256 (64.65%) physicians answered that they do not recommend their hypertensive patients with AH to undergo surgical prevention of ischaemic stroke. The obtained findings reflect poor awareness of physicians of the primary medical care (PMC) on diagnostic criteria for cerebrovascular diseases (CVDs). The revealed problems concerning follow up of CVDs would help decide upon publication and active distribution of All-Russian guidelines for primary care physicians (therapeutists, cardiologists, neurologists, functionalinsts) on selection patients for BCA USS and angiosurgical interventions. A draft of the informational letter "Indications for BCA ultrasound examination" is attached to the article.

Utility of Lower Extremity Doppler in Patients with Lower Extremity Cellulitis: A Need to Change the Practice?

OBJECTIVES: Cellulitis and deep vein thrombosis (DVT) in the lower extremities (LE) often have similar presentations: erythema, swelling, and calf tenderness. The overlap of these symptoms often results in physicians ordering unnecessary LE Doppler ultrasounds in patients with LE cellulitis. This practice leads to subjecting patients to unwarranted procedures and results in increased healthcare costs. We aimed to determine the percentage of Doppler ultrasounds performed in patients admitted with LE cellulitis and the prevalence of DVT in that population. METHODS: A retrospective chart review was performed of the patients admitted January 1, 2009 to June 30, 2013 who had a diagnosis of LE cellulitis. The number of Doppler ultrasounds performed and the presence of DVT was recorded. Patients were divided into groups of Doppler ultrasounds with no DVT and Doppler ultrasounds that were positive for DVT to compare the risk factors. RESULTS: There were 624 patients identified using the International Classification of Diseases, 9th Revision code for LE cellulitis at the time of admission. Slightly more than half of the subjects were men (315/624) and the average age was 61.4 ± 18.8 years (mean ± standard deviation). There were 417 (66.8%) patients who underwent Doppler ultrasound. Only 25 (5.9%) patients had DVT. Multivariate analysis showed that prior cerebrovascular accident, calf swelling, and history of thromboembolism were statistically significant predictors for DVT (P < 0.05). CONCLUSIONS: A concurrent incidence of DVT and LE cellulitis is rare. In the absence of known risk factors of DVT, the yield of LE Doppler is low and Doppler ultrasound is not required as a part of a standard admission evaluation.

Post Splenectomy Outcome in ß-Thalassemia.

OBJECTIVES: To evaluate changes in annual blood transfusion requirements and complications after splenectomy in patients with ß-thalassemia. METHODS: Forty post-splenectomy ß-thalassemic patients aged 8-33 y, receiving regular blood transfusions and chelation therapy were included and non transfusion dependant patients were excluded from this retrospective cross-sectional study. Details about their surgery, transfusion requirements, and platelet levels were recorded on a standard proforma. All patients underwent a B-mode and color-coded duplex sonography of the hepatoportal system during the study period. RESULTS: The average ferritin level in the year prior to the study was 4432 mcg/L (range 480-12,200 mcg/L). The annual blood transfusion requirement in the first year and 5 y post splenectomy [mean ± SD (138.41 ± 90.38 ml/kg/y); (116 ± 41.44 ml/kg/y)] were significantly different from requirements before splenectomy [(mean ± SD) 294.85 ± 226 ml/kg/y; p value <0.001]. There was a significant rise in platelet counts within 24 h post splenectomy with a mean rise of 4,51,000/mm(3) (p value < 0.001). During the follow up period, infections were noted in 50 % of patients, with malaria (18.75 %) being the most common. Doppler study of the portal system in one case showed portal vein thrombosis. CONCLUSIONS: A significant sustained fall in annual blood transfusion requirement and a rise in platelet counts occurred post-splenectomy. Increase in annual blood transfusion requirement should be investigated to find the cause.

Appropriate use of D-dimer testing can minimize over-utilization of venous duplex ultrasound in a contemporary high-volume hospital.

BACKGROUND: The sensitivity of d-dimer (DD) in detecting deep venous thrombosis (DVT) is remarkably high; however, many institutions send patients immediately for a venous duplex ultrasound (VDU). This study was designed to examine the appropriate utilization of DD and VDU in a high-volume hospital. METHODS: A retrospective study was conducted on consecutive patients who presented to a high-volume emergency department (ED) with lower extremity limb swelling/pain over a 30-day period, who were sent for VDU during an evaluation for DVT. VDU data were merged with electronic DD laboratory results. The enzyme-linked immunosorbent assay method was used to provide DD values and thresholds. Values above 0.60 mg/fibrinogen equivalent unit (FEU) were considered abnormal. RESULTS: We reviewed the medical records of 517 ED patients in the month of June 2013. After applying the Wells criteria, 157 patients (30.4%) were excluded because of a history of DVT or pulmonary embolism, having been screened for shortness of breath, or sent for surveillance-leaving 360 for analysis. The average age was 59.3 ± 16.5 years with more women (210, 58.3%) and the majority reported limb pain or swelling (73.9%). DD was performed on 51 patients with an average value of 3.6 ± 5.4 mg/FEU, of which 43 (84.3%) were positive. DD identified all positive and negative DVT patients (100% sensitivity and negative predictive value), but also included 40 false positives (16.7% specificity). On the other hand, 309 patients were sent directly to VDU without DD; of those, 43 (13.9%) were positive for DVT. However, 266 (86.1%) patients were negative for DVT by VDU without DD and these were deemed improper by our current study protocol. Potential charge savings were calculated as VDU for all (360 × $1000 = $360,000), DD for all (360 × $145 = $52,200), and VDU for both true and false positives (estimated to be about 25% of the cases; 90 × $1000 = $90,000); this equals a charge savings of $217,800 and would avoid unnecessary VDUs. CONCLUSIONS: Based on the results of our study, we suggest that the DD test be utilized during the initial work-up for patients with limb swelling/pain in the emergency room. Appropriate utilization of DD, as well as other clinical criteria, may limit the over-utilization and added cost of VDU, without a negative impact on patient care. The results of DD tests should be utilized to limit the number of patients sent for VDU to only those patients with a positive DD or other significant underlying concerns.

The utility of screening for asymptomatic lower extremity deep venous thrombosis during inflammatory bowel disease flares: a pilot study.

BACKGROUND: Asymptomatic deep vein thrombosis (DVT) occurs in up to 11% of medical inpatients. The incidence of asymptomatic DVT among patients with inflammatory bowel disease (IBD) is unknown but may be even higher. D-dimer is effective for DVT screening, but its utility has not been studied in the IBD population. METHODS: Hospitalized and ambulatory patients with IBD during flares were recruited between 2009 and 2011. Those with clinical symptoms of venous thromboembolism or previous venous thromboembolism were excluded. We determined the prevalence of DVT among asymptomatic subjects using lower extremity Doppler ultrasound and assessed the performance characteristics of the D-dimer in this high-risk study population. RESULTS: We enrolled 101 hospitalized and 49 ambulatory patients with IBD during active flares. There were no cases of proximal DVT detected by lower extremity Doppler ultrasound. The 95% confidence interval (CI) for the rate of proximal DVT was 0% to 2%. D-dimer was elevated in 60% of subjects without DVT, occurring more frequently among hospitalized than ambulatory subjects [89% versus 65%, P = 0.01; adjusted odds ratio (aOR), 4.16, 95% CI, 1.58-10.9]. Other predictors of elevated D-dimer were incremental decade in age (aOR, 1.97; 95% CI, 1.24-3.14); ulcerative colitis versus Crohn's disease diagnosis (aOR, 3.38; 95% CI, 1.29-8.84); and every 10-unit increase in C-reactive protein (aOR, 1.33; 95% CI, 1.09-1.62). CONCLUSION: From this pilot study, there appears to be low prevalence of asymptomatic DVTs among patients with IBD during flares. The high prevalence of elevated D-dimer in DVT-negative patients limits its utility in IBD.

The impact of endograft surveillance on a vascular imaging service.

BACKGROUND: Surveillance is considered mandatory after endovascular repair (EVR), but its impact on imaging services remains unreported. This study reports the effect of EVR surveillance on imaging resources. METHODS: A single-center's duplex database was interrogated from January 1, 2004 to January 1, 2012. All examinations requested by a vascular surgeon were reported, including preoperative abdominal aortic aneurysms, surveillance after EVR, lower limb arterial and venous duplex, and arteriovenous fistulae. RESULTS: A total of 24 309 patients underwent duplex. The EVR surveillance increased from 192 scans in 2004 to 1325 scans in 2011, 9.5% (192 of 2030) and 34.4% (1325 of 3850) of each year's examinations. By 2011, EVR surveillance was the most common indication for duplex. CONCLUSION: Lifelong EVR surveillance creates a rapidly increasing workload for imaging services. Further research should aim to reduce the burden of EVR surveillance. Targeting surveillance to the minority of patients at greatest risk of endograft failure might optimize the usage of imaging resources.

Growth of carotid artery duplex ultrasound among Medicare beneficiaries (2000-2007).

OBJECTIVE: Although intervention in asymptomatic carotid artery stenosis remains controversial, most carotid interventions are performed in asymptomatic individuals. Carotid duplex ultrasound is the diagnostic test that precedes more than 90% of carotid interventions. In terms of economic incentives, providers who perform carotid artery revascularization may experience synergy if they also provide carotid duplex ultrasound, because the diagnostic service is reimbursed and also can lead to referrals for revascularization procedures. To test the hypothesis that providers of revascularization services are incentivized to increase utilization of carotid duplex ultrasound, we compared the utilization of carotid duplex ultrasound among Medicare beneficiaries by three specialties that perform revascularization for carotid stenosis (interventional radiology, vascular surgery, and cardiology) with one that usually does not (diagnostic radiology). MATERIALS AND METHODS: We analyzed 100% of procedure-specific claims submitted to Medicare by the four specialties during 2000, 2002, 2004, 2005, 2006, and 2007. Only professional and global components of services approved by Medicare were included. Compounded annual growth rates were used to compare utilization by different specialties. RESULTS: Utilization by diagnostic radiology increased at a compound annual growth rate of 1% during 2000-2007. Interventional radiology and vascular surgery experienced higher compound annual growth rates of 3% and 6%, respectively. Utilization by cardiology increased at a rate 11 times that of diagnostic radiology, translating into an additional 960 procedures per 100,000 Medicare beneficiaries by cardiology in 2007 than in 2000. CONCLUSION: Medicare beneficiaries are increasingly being tested for carotid artery stenosis, especially by specialties that perform revascularization for carotid stenosis. The health benefits of this practice are uncertain.

Surveillance imaging modality does not affect detection rate of asymptomatic secondary interventions following EVAR.

OBJECTIVES: Literature reports that surveillance imaging following endovascular aortic aneurysm repair (EVAR) gives rise to asymptomatic secondary interventions (SI) in 1.4-9% of cases. This retrospective study aimed to evaluate whether the modality of surveillance imaging influences the detection rate of asymptomatic SI. MATERIALS AND METHODS: Two EVAR surveillance protocols were compared at the same vascular centre. Protocol I, performed from January 2003 to December 2006, consisted of colour duplex ultrasound scan (CDU) plus CT angiography (CTA) 1 month after procedure and every 6 months thereafter. Protocol II, performed from January 2007 to June 2010, consisted of CDU plus CTA 1 month after operation and CDU plus plain abdominal films (XR) every 6 months thereafter. In the second protocol, CTA was carried out only during follow-up in specific conditions. The term 'asymptomatic SI' was used when the necessity for SI was detected by imaging alone on an elective basis, prior to development of any symptoms. RESULTS: Enrolment included 376 and 341 consecutive patients with a mean follow-up of 1148 days (range 1-3204 days) and 942 days (range1-1512 days) in Protocols I and II, respectively (p < 0.001). Freedom rates from aneurysmal rupture, freedom from SI and detection rate for asymptomatic SI at 3 years were 98.3% and 98.7% (p = 0.456), 82% and 83.5%(p = 0.876) and 8.8% (n = 33/376) and 8.5%(n = 25/341) (p = 0.49) in Protocols I and II, respectively. Estimated comparison of the costs, radiation exposure and contrast used at 3 years in Protocol I versus Protocol II showed that Protocol II allowed for a three-, four- and six fold reduction in overall costs, radiation exposure and contrast used, respectively (p < 0.0001). CONCLUSIONS: The detection rate of asymptomatic SI following EVAR is not affected by the type of surveillance imaging. A surveillance schedule based primarily on CDU and XR appears to be justified.

Completion imaging after carotid endarterectomy in the Vascular Study Group of New England.

OBJECTIVES: We studied surgeons' practice patterns in the use of completion imaging (duplex or arteriography), and their association with 30-day stroke/death and 1-year restenosis after carotid endarterectomy (CEA). METHODS: Using a retrospective analysis of 6115 CEAs, we categorized surgeons based on use of completion imaging as rarely (<5% of CEAs), selective (5% to 90%), or routine (≥90%). Crude and risk-adjusted 30-day stroke/death and 1-year restenosis rates were examined across surgeon practice patterns. Finally, we audited 90 operative reports of patients who underwent re-exploration and characterized findings and interventions. We analyzed the effect of re-exploration on outcomes. RESULTS: Practice patterns in completion imaging varied: 51% of surgeons performed completion imaging rarely, 22% selectively, and 27% routinely. Crude 30-day stroke/death rates were highest among surgeons who routinely used completion imaging (rarely: 1.7%; selectively: 1.2%, routinely: 2.4%; P = .05). However, after adjusting for patient characteristics predictive of stroke/death, the effect of surgeon practice pattern was not statistically significant (odds ratio [OR] for routine-use surgeons, 1.42; 95% CI, 0.93-2.17; P = .10; selective-use surgeons, 0.75; 95% CI, 0.40-1.41; P = .366). Stenosis >70% at 1 year showed a trend toward lowest rates for surgeons who performed completion imaging (rarely: 2.8%, selectively: 1.1%, and routinely: 1.1%; P = .09). This effect became statistically significant for selective-use surgeons after adjustment (hazard risk [HR] for selective-use surgeons, 0.52; 95% CI, 0.29-0.92; P = .02). Overall, 178 patients (2.9%) underwent operative re-exploration. Routine-use surgeons were most likely to perform re-exploration (7.6% routine, 0.8% selective, 0.9% rare; P < .001). An audit of 90 re-explored patients demonstrated technical problems, the most common being flap, debris, and plaque. Rates of stroke/death were higher among patients who underwent re-exploration (3.9% vs 1.7%; P = .03); however, this affect was attenuated after adjustment (OR, 2.1; 95% CI, 0.9-5.0; P = .08). CONCLUSIONS: The use of completion imaging during CEA varies widely across our region. There is little evidence that surgeons who use completion imaging have lower rates of 30-day stroke/death, although selective use of completion imaging is associated with a small but a significant reduction in stenosis 1 year after surgery. We also demonstrate an association between re-exploration and higher risk of 30-day stroke/death, although this effect was attenuated after adjustment for patient-level predictors of stroke/death. Future work is needed to direct the selective use of completion imaging to prevent stroke, rather than cause unnecessary re-exploration.

Duplex ultrasound screening for deep vein thrombosis in asymptomatic trauma patients: a survey of individual trauma surgeon opinions and current trauma center practices.

BACKGROUND: Many national agencies have suggested that deep vein thrombosis (DVT) rates measure quality of hospital care. However, none provide recommendations for standardized screening. If screening practices vary among clinicians or hospitals, DVT rates could be biased-centers which perform more duplex ultrasounds report more DVTs. We hypothesized that trauma surgeons have varying opinions regarding duplex ultrasound screening for DVT in asymptomatic trauma patients, which result in varying practice patterns. METHODS: We conducted two web-based surveys regarding the use of duplex ultrasound screening for DVT in asymptomatic trauma patients. The first (individual provider level) surveyed members of two national trauma surgery organizations (American Association for the Surgery of Trauma and Eastern Association for the Surgery of Trauma). The second (trauma center level) surveyed practice patterns of National Trauma Data Bank hospitals. RESULTS: Three hundred seventeen individual surgeons completed surveys. There was wide variation in individual opinions regarding DVT screening in asymptomatic trauma patients (53% agree, 36% disagree, and 11% neither agree nor disagree). Two hundred thirteen National Trauma Data Bank hospitals completed surveys of which 28% (n=60) have a written guideline regarding DVT screening in asymptomatic trauma patients. The proportion of centers with a written protocol varied significantly by trauma center level (p<0.001) but not by teaching status. Opinions and practice patterns suggest that screening should start early and be performed weekly. The main risk factors used to suggest DVT screening are spinal cord injury and pelvic fracture. CONCLUSIONS: There are wide variations in trauma surgeons' opinions and trauma centers' practices regarding duplex ultrasound screening for DVT in asymptomatic trauma patients. This variability combined with the fact that performing more duplex ultrasounds finds more DVTs may influence reported DVT rates. DVT rates alone are biased and not reflective of true quality of trauma care.

The current state of practice in the diagnosis of venous thromboembolism at an academic medical center.

Evidence-based guidelines for the diagnosis of venous thromboembolism (VTE) have been recommended, yet the adoption of such guidelines into daily practice is unknown. The purpose of this study was to describe the current practices in the diagnosis of VTE. Medical records of 1161 adult patients who underwent lower extremity venous duplex scans (VDS), chest computerized tomographic (CT) angiography, or ventilation and perfusion (V/Q) scans during a 6-month period were retrospectively reviewed in an academic medical center. Patients who were first diagnosed by CT or V/Q scan still underwent a VDS. Nine patients at high risk had incomplete CT scans, yet no further tests were performed. Five pregnant patients had CT scans as the initial test instead of being screened with VDS or V/Q scanning. Inappropriate use of imaging tests was documented. The recommended guidelines of using clinical probability and D-dimer as the initial screening tests for VTE diagnosis were underused.

The impact of a systemwide policy for emergent off-hours venous duplex ultrasound studies.

BACKGROUND: We evaluated the impact of an after-hours policy regulating venous duplex ultrasound (VDU) for deep vein thrombosis (DVT) diagnosis on resource utilization and patient care. METHODS: On July 1, 2007, we altered the approach to emergent VDU of patients with potential DVT during off-hours (defined as 5:00 p.m. to 7:00 a.m. weekdays, after 3:30 p.m. Saturdays and Sundays). Instead of 24 hr access, we permitted a venous duplex study in the noninvasive vascular laboratory (NIVL) only after meeting set criteria developed collaboratively across services. In the emergency department (ED), we based all VDU requests on a preset modified Wells score (MWS) as determined by the ED physician. Those patients with MWS 0 or 1 and those above 1 who could receive empiric single-dose low-molecular weight heparin (LMWH) received next-morning imaging unless consultation with a vascular surgeon created an emergent imaging plan. In parallel, inpatient emergent VDU was permitted only after contact with an attending vascular surgeon and where empiric short-term anticoagulation could not occur safely. We tracked NIVL utilization, patient morbidity, sonographer retention, and satisfaction. RESULTS: The number of overall off-hours emergent VDUs decreased from 59 to 19/month after implementation. Testing was deferred in 52 ED patients: 15 stayed in the ED for testing in the morning and 37 were discharged to be tested the following day. Thirty-one of 37 patients returned for testing as outpatient follow-up. Twenty-eight received ED LMWH while awaiting testing. No adverse events were noted with the delay. The mean MWS for ED after-hours studies was 2.9+/-1.6 and that for deferred ER studies was 2.4+/-1.3 (p=0.005). Incidentally, overall off-hours inpatient and ED VDU requests decreased 64% with no clinical adverse events in the first year. The rate of overall positive studies done off-hours increased from 6.7% to 20% (p<0.0001). Sonographer satisfaction was maintained with regulation of call. CONCLUSION: Our collaborative approach allowed off-hour VDU utilization to decrease without any measurable negative care impact.