“Bull's-eye” sign on gadolinium-enhanced magnetic resonance venography determines thrombus presence and age: A preliminary study

AbstractPurpose: Venous thrombosis is associated with a significant inflammatory response, which can be visualized by gadolinium magnetic resonance venography (MRV). Gadolinium extravasates into tissue during inflammation, producing perithrombus enhancement on magnetic resonance scanning. This study determines (1) whether gadolinium enhancement occurs during deep venous thrombosis (DVT); and (2) whether this enhancement changes with time and can therefore establish the age of thrombus.Methods: Patients with a diagnosis of iliofemoral DVT by duplex ultrasound who were referred for MRV to document central thrombus extent were studied. T1 weighted images were obtained before and after gadolinium injection (0.1 mmol/kg); repeat scans were obtained up to 3 months thereafter. At the level of maximum thrombus, measurements of signal intensity were made at the periphery (rim), and the center of the thrombosed vein, as well as the contralateral normal vein, on images after gadolinium enhancement. Rim-center vein signal intensity ratios were then calculated and followed.Results: A total of 39 scans were obtained in 14 patients (eight men, six women). The thrombosed veins were enlarged, with a peripheral rim of enhancement (“bull's-eye” sign). The rim-center ratio for thrombosed veins (2.16 ± 0.18) was different from that of normal veins (0.66 ± 0.10; n = 39; p < 0.001). For all acute studies (≤14 days) the rim-center ratio was 2.38 ± 0.17 (n = 31), whereas for all chronic studies (>14 days) the rim-center ratio was 1.29 ± 0.44 (n = 8; p = 0.001). Among patients who underwent both early and late studies, the rim-center ratio dropped significantly, from 2.33 ± 0.20 acutely to 1.29 ± 0.44 in chronic studies (n = 8; p = 0.03). One patient with active malignancy had a paradoxic increase in rim-center ratio over time and a clinical recurrence of symptoms, suggesting active thrombosis.Conclusions: We conclude that (1) a pattern of peripheral gadolinium enhancement (bull's-eye sign) is seen around acutely thrombosed veins on gadolinium-enhanced MRV, facilitating DVT diagnosis; and (2) the ratio of signal intensity at the rim versus the center of the thrombosed vein may be a good discriminator of acute compared with chronic DVT, which may help direct therapy. (J Vasc Surg 1997;26:809-16.

Variation in practice patterns among specialties in the acute management of atrial fibrillation

Abstract Background Atrial fibrillation (AF) is commonly managed by a variety of specialists. Current guidelines differ in their recommendations leading to uncertainty regarding important clinical decisions. We sought to document practice pattern variation among cardiologists, emergency physicians (EP) and hospitalists at a single academic, tertiary-care center. Methods A survey was created containing seven clinical scenarios of patients presenting with AF. We analyzed respondent choices regarding rate vs rhythm control, thromboembolic treatment and hospitalization strategies. Finally, we contrasted our findings with a comparable Australasian survey to provide an international reference. Results There was a 78% response rate (124 of 158), 37% hospitalists, 31.5% cardiologists, and 31.5% EP. Most respondents chose rate over rhythm control (92.2%; 95% CI, 89.1% - 94.5%) and thromboembolic treatment (67.8%; 95% CI, 63.8% - 71.7%). Compared to both hospitalists and EPs, cardiologists were more likely to choose thromboembolic treatment for new and paroxysmal AF (adjusted OR 2.38; 95% CI, 1.05 - 5.41). They were less likely to favor hospital admission across all types of AF (adjusted OR 0.36; 95% CI, 0.17 - 0.79) but thought cardiology consultation was more important (adjusted OR 1.88, 95% CI, 0.97 - 3.64). Australasian physicians were more aggressive with rhythm control for paroxysmal AF with low CHADS2 score compared to US physicians. Conclusions Significant variation exists among specialties in the management of acute AF, likely reflecting a lack of high quality research to direct the provider. Future studies may help to standardize practice leading to decreased rates of hospitalization and overall cost.http://deepblue.lib.umich.edu/bitstream/2027.42/110777/1/12872_2015_Article_9.pd

Barriers to integrating direct oral anticoagulants into anticoagulation clinic care: A mixedâ methods study

BackgroundOutpatient anticoagulation clinics were initially developed to care for patients taking vitamin K antagonists such as warfarin. There has not been a systematic evaluation of the barriers and facilitators to integrating direct oral anticoagulant (DOAC) care into outpatient anticoagulation clinics.MethodsWe performed a mixed methods study consisting of an online survey of anticoagulation clinic providers and semiâ structured interviews with anticoagulation clinic leaders and managers between March and May of 2017. Interviews were transcribed and coded, exploring for themes around barriers and facilitators to DOAC care within anticoagulation clinics. Survey questions pertaining to the specific themes identified in the interviews were analyzed using summary statistics.ResultsSurvey responses were collected from 159 unique anticoagulation clinics and 20 semiâ structured interviews were conducted. Three primary barriers to DOAC care in the anticoagulation clinic were described by the interviewees: (a) a lack of provider awareness for ongoing monitoring and services provided by the anticoagulation clinic; (b) financial challenges to providing care to DOAC patients in an anticoagulation clinic model; and (c) clinical knowledge versus scope of care by the anticoagulation staff. These themes linked to three key areas of variation, including: (a) the size and hospital affiliation of the anticoagulation clinic; (b) the use of faceâ toâ face versus telephoneâ based care; and (c) the use of nurses or pharmacists in the anticoagulation clinic.ConclusionsAnticoagulation clinics in the United States experience important barriers to integrating DOAC care. These barriers vary based on the clinic size, model for warfarin care, and staff credentials (nursing or pharmacy).Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147845/1/rth212157.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147845/2/rth212157_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147845/3/rth212157-sup-0001-Supinfo.pd

Periprocedural bridging anticoagulation in patients with venous thromboembolism: A registry- based cohort study

BackgroundUse of bridging anticoagulation increases a patient’s bleeding risk without clear evidence of thrombotic prevention among warfarin- treated patients with atrial fibrillation. Contemporary use of bridging anticoagulation among warfarin- treated patients with venous thromboembolism (VTE) has not been studied.MethodsWe identified warfarin- treated patients with VTE who temporarily stopped warfarin for a surgical procedure between 2010 and 2018 at six health systems. Using the 2012 American College of Chest Physicians guideline, we assessed use of periprocedural bridging anticoagulation based on recurrent VTE risk. Recurrent VTE risk and 30- day outcomes (bleeding, thromboembolism, emergency department visit) were each assessed using logistic regression adjusted for multiple procedures per patient.ResultsDuring the study period, 789 warfarin- treated patients with VTE underwent 1529 procedures (median, 2; interquartile range, 1- 4). Unadjusted use of bridging anticoagulation was more common in patients at high risk for VTE recurrence (99/171, 57.9%) than for patients at moderate (515/1078, 47.8%) or low risk of recurrence (134/280, 47.86%). Bridging anticoagulation use was higher in high- risk patients compared with low- or moderate- risk patients in both unadjusted (P = .013) and patient- level cluster- adjusted analyses (P = .031). Adherence to American College of Chest Physicians guidelines in high- and low- risk patients did not change during the study period (odds ratio, 0.98 per year; 95% confidence interval, 0.91- 1.05). Adverse events were rare and not statistically different between the two treatment groups.ConclusionsBridging anticoagulation was commonly overused among low- risk patients and underused among high- risk patients treated with warfarin for VTE. Adverse events were rare and not different between the two treatment groups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156139/2/jth14903_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156139/1/jth14903.pd

Receipt of Cardiac Medications Upon Discharge Among Men and Women With Acute Coronary Syndrome and Nonobstructive Coronary Artery Disease

Background Management of acute coronary syndrome (ACS) patients with nonobstructive epicardial coronary artery disease (CAD) remains poorly understood. Hypothesis Acute coronary syndrome patients with nonobstructive CAD are less likely to receive effective cardiac medications upon discharge from the hospital. Methods We identified patients hospitalized with ACS that underwent coronary angiography and had a 6-month follow-up. Patients were grouped by CAD severity: nonobstructive CAD (<50% blockage in all vessels) or obstructive CAD (≥50% blockage in ≥ 1 vessels). Data were collected on demographics, medications at discharge, and adverse outcomes at 6 months, for all patients. Results Of the 2264 ACS patients included in the study: 123 patients had nonobstructive CAD and 2141 had obstructive CAD. Cardiac risk factors including hypertension and diabetes were common among patients with nonobstructive CAD. Men and women with nonobstructive CAD were less likely to receive cardiac medications compared to patients with obstructive CAD including aspirin (87.8% vs 95.0%, P = 0.001), Β-blockers (74.0% vs 89.2%, P < 0.001), or statins (69.1% vs 81.2%, P = 0.001). No gender-related differences in discharge medications were observed for patients with nonobstructive CAD. However, women with nonobstructive CAD had similar rates of cardiac-related rehospitalization as men with obstructive CAD (23.3% and 25.9%, respectively). Conclusions Patients with nonobstructive CAD are less likely to receive evidence-based medications compared to patients with obstructive CAD, despite the presence of CAD risk factors and occurrence of an ACS event. Further research is warranted to determine if receipt of effective cardiac medications among patients with nonobstructive CAD would reduce cardiac-related events. Copyright © 2010 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64902/1/20701_ftp.pd

Creatinine monitoring patterns in the setting of direct oral anticoagulant therapy for non-valvular atrial fibrillation

Guidelines and experts note that patients with atrial fibrillation require regular renal function monitoring to ensure safe use of direct oral anticoagulants (DOACs). Insufficient monitoring could lead to inappropriate dosing and adverse events. Our objective was to describe the frequency of insufficient creatinine monitoring among patients on DOACs, and to describe clinical factors associated with insufficient monitoring. We hypothesized that renal impairment would be associated with insufficient monitoring. A retrospective cohort study was performed with data from the Michigan Anticoagulant Quality Improvement Initiative. Patients were included if they initiated DOAC therapy for stroke prevention related to atrial fibrillation, remained on therapy for ≥ 1 year, and had baseline creatinine and weight measurements. Creatinine clearance (CrCl) was calculated via Cockcroft-Gault equation. Our outcome was the presence of insufficient creatinine monitoring, defined as: \u3c 1 creatinine level/year for patients with CrCl \u3e 50, or \u3c 2 creatinine levels/year for patients with CrCl ≤ 50. Multivariable analysis was done via logistic regression. Study population included 511 patients. In overall, 14.0% of patients received insufficient monitoring. Among patients with CrCl \u3e 50, 11.5% had \u3c 1 creatinine level/year. Among patients with CrCl ≤ 50, 27.1% received \u3c 2 creatinine levels/year. Baseline renal dysfunction was associated with a higher likelihood of insufficient creatinine monitoring (adjusted odds ratio 3.64, 95% confidence interval 1.81-7.29). This shows a significant gap in the monitoring of patients on DOACs-patients with renal impairment are already at higher risk for adverse events. Future studies are needed to describe the barriers in monitoring these patients and to identify how to optimally address them

Length of Anticoagulation in Provoked Venous Thromboembolism: A Multicenter Study of How Real-World Practice Mirrors Guideline Recommendations

Background For more than a decade, guidelines have recommended a limited 3 months of anticoagulation for the treatment of provoked venous thromboembolism (VTE). How closely real-world practice follows guideline recommendations is not well described. Methods and Results In our multicenter, retrospective cohort study, we evaluated trends in anticoagulation duration for patients enrolled in the MAQI(2) (Michigan Anticoagulation Quality Improvement Initiative) registry who were receiving anticoagulation for a provoked VTE. The MAQI(2) registry comprises 6 centers in Michigan that manage patients\u27 long-term anticoagulation. We identified 474 patients on warfarin and 302 patients on direct oral anticoagulants who were receiving anticoagulation for a primary indication of provoked VTE between 2008 and 2020. Using a predefined threshold of 120 days (3 months plus a buffer period), predictors of extended anticoagulant use were identified using multivariable logistic regression. Most patients received \u3e120 days of anticoagulation, regardless of which medication was used. The median (25th-75th percentile) length of treatment for patients taking warfarin was 142 (91-234) days and for direct oral anticoagulants was 180 (101-360) days. Recurrent VTE (odds ratio [OR], 2.75 [95% CI, 1.67-4.53]), history of myocardial infarction (OR, 3.92 [95% CI, 1.32-11.7]), and direct oral anticoagulant rather than warfarin use (OR, 2.22 [95% CI, 1.59-3.08]) were independently associated with prolonged anticoagulation. Conclusions In our cohort of patients with provoked VTE, most patients received anticoagulation for longer than the guideline-recommended 3 months. This demonstrates a potential opportunity to improve care delivery and reduce anticoagulant-associated bleeding risk

AREDS Formula, Warfarin, and Bleeding: A Case Report from the Michigan Anticoagulation Quality Improvement Initiative

Importance. The anticoagulant warfarin has been shown to interact with other medications, vitamin K containing foods, and over-the-counter products. These interactions may inhibit or potentiate the effect of warfarin, resulting in serious clotting or bleeding events. Observations. We report the case of an 84-year-old woman with atrial fibrillation, prescribed warfarin in May 2010 for stroke prevention. Her international normalized ratio (INR) was stable until April 2013, when she was prescribed AREDS (Age Related Eye Disease Study) formula pills, an eye vitamin compound, to slow the progression of age-related macular degeneration. This change was not reported to the Anticoagulation Service. Eighteen days later, she presented to the ED with groin and back pain and an INR of 10.4. An abdominal CT revealed a retroperitoneal hemorrhage with extension in multiple muscles. Both warfarin and AREDS were discontinued and the patient was discharged to subacute rehabilitation. This case was reviewed by the Anticoagulation Service and actions were taken to prevent similar adverse events. Conclusions. This report provides an example of the potential danger of supplement use, in this case, AREDS formula, in patients prescribed warfarin, and the importance of communicating medication changes to the providers responsible for warfarin management

Comparison of temporary interruption with continuation of direct oral anticoagulants for low bleeding risk procedures

INTRODUCTION: Limited data is available on the rates of bleeding and thromboembolic events for patients undergoing low bleeding risk procedures while taking direct oral anticoagulants (DOAC). METHODS: Adults taking DOAC in the Michigan Anticoagulation Quality Improvement Initiative (MAQI(2)) database who underwent a low bleeding risk procedure between May 2015 and Sep 2019 were included. Thirty-day bleeding (of any severity), thromboembolic events, and death were compared between DOAC temporarily interrupted and continued uninterrupted groups. Adverse event rates were compared using an inverse probability weighting propensity score. RESULTS: There were 820 patients who underwent 1412 low risk procedures. DOAC therapy was temporarily interrupted in 371 (45.2%) patients (601 [42.6%] procedures) and continued uninterrupted in 449 (54.8%) patients (811 [57.4%] procedures). DOAC patients with temporary interruptions were more likely to have diabetes, prior stroke or TIA, prior bleeding, higher CHA2DS2-VASc, and higher modified HAS-BLED scores. DOAC interruption was common for gastrointestinal endoscopy, electrophysiology device implantation, and cardiac catheterization while it was less common for cardioversion, dermatologic procedures, and subcutaneous injection. After propensity score adjustment, bleeding risk was lower in the DOAC temporary interruption group (OR 0.62, 95% CI 0.41-0.95) as compared to the group with continuous DOAC use. Rates of thromboembolic events and death did not differ significantly between the two groups. CONCLUSIONS: DOAC-treated patients undergoing low bleeding risk procedures may experience lower rates of bleeding when DOAC is temporarily interrupted. Prospective studies focused on low bleeding risk procedures are needed to identify the safety DOAC management strategy