Predicting Postoperative Troponin in Patients Undergoing Elective Hip or Knee Arthroplasty: A Comparison of Five Cardiac Risk Prediction Tools.

Background: Elderly patients undergoing hip or knee arthroplasty are at a risk for myocardial injury after noncardiac surgery (MINS). We evaluated the ability of five common cardiac risk scores, alone or combined with baseline high-sensitivity cardiac troponin I (hs-cTnI), in predicting MINS and postoperative day 2 (POD2) hs-cTnI levels in patients undergoing elective total hip or knee arthroplasty. Methods: This study is ancillary to the Genetics-InFormatics Trial (GIFT) of Warfarin Therapy to Prevent Deep Venous Thrombosis, which enrolled patients 65 years and older undergoing elective total hip or knee arthroplasty. The five cardiac risk scores evaluated were the atherosclerotic cardiovascular disease calculator (ASCVD), the Framingham risk score (FRS), the American College of Surgeon's National Surgical Quality Improvement Program (ACS-NSQIP) calculator, the revised cardiac risk index (RCRI), and the reconstructed RCRI (R-RCRI). Results: None of the scores predicted MINS in women. Among men, the ASCVD (C-statistic of 0.66; p=0.04), ACS-NSQIP (C-statistic of 0.69; p=0.01), and RCRI (C-statistic of 0.64; p=0.04) predicted MINS. Among all patients, spearman correlations (r s) of the risk scores with the POD2 hs-cTnI levels were 0.24, 0.20, 0.11, 0.11, and 0.08 for the ASCVD, Framingham, ACS-NSQIP, RCRI, and R-RCRI scores, respectively, with p values of <0.001, <0.001, <0.001, 0.006, and 0.025. Baseline hs-cTnI predicted MINS (C-statistics: 0.63 in women and 0.72 in men) and postoperative hs-cTnI (r s = 0.51, p=0.001). Conclusion: In elderly patients undergoing elective hip or knee arthroplasty, several of the scores modestly predicted MINS in men and correlated with POD2 hs-cTnI.

Antithrombotic Therapy for VTE Disease: Second Update of the CHEST Guideline and Expert Panel Report.

BACKGROUND: This is the 2nd update to the 9th edition of these guidelines. We provide recommendations on 17 PICO (Population, Intervention, Comparator, Outcome) questions, four of which have not been addressed previously. METHODS: We generate strong and weak recommendations based on high-, moderate-, and low-certainty evidence, using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) methodology. RESULTS: The panel generated 29 guidance statements, 13 of which are graded as strong recommendations, covering aspects of antithrombotic management of VTE from initial management through secondary prevention and risk reduction of postthrombotic syndrome. Four new guidance statements have been added that did not appear in the 9th edition (2012) or 1st update (2016). Eight statements have been substantially modified from the 1st update. CONCLUSION: New evidence has emerged since 2016 that further informs the standard of care for patients with VTE. Substantial uncertainty remains regarding important management questions, particularly in limited disease and special patient populations.

Trauma patients at risk for venous thromboembolism who undergo routine duplex ultrasound screening experience fewer pulmonary emboli: A prospective randomized trial.

BACKGROUND: Although guidelines are established for the prevention and management of venous thromboembolism (VTE) in trauma, no consensus exists regarding protocols for the diagnostic approach. We hypothesized that at-risk trauma patients who undergo duplex ultrasound (DUS) surveillance for lower extremity deep venous thrombosis (DVT) will have a lower rate of symptomatic or fatal pulmonary embolism (PE) than those who do not undergo routine surveillance. METHODS: Prospective, randomized trial between March 2017 and September 2019 of trauma patients admitted to a single, level 1 trauma center, with a risk assessment profile score of ≥5. Patients were randomized to receive either bilateral lower extremity DUS surveillance on days 1, 3, and 7 and weekly during hospitalization ultrasound group (US) or no surveillance no ultrasound group (NoUS). Rates of in-hospital and 90-day DVT and PE were reported as was DVT propagation and all-cause mortality. Standard care for the prevention and management of VTE per established institutional protocols was provided to all patients. RESULTS: A total of 3,236 trauma service admissions were screened, and 1,989 moderate- and high-risk patients were randomized (US, 995; NoUS, 994). The mean ± SD age was 62 ± 20.1 years, Injury Severity Score was 14 ± 9.7, risk assessment profile was 7.1 ± 2.4, and 97% suffered blunt trauma. There was no difference in demographics or VTE risk factors between the groups. There were significantly fewer in-hospital PE in the US group than the NoUS group (1 [0.1%] vs. 9 [0.9%], p = 0.01). The US group experienced more in-hospital below-knee DVTs (124 [12.5%] vs. 8 [0.8%], p < 0.001) and above-knee DVTs (19 [1.9%] vs. 8 [0.8%], p = 0.05). There was no difference in 90-day PE or DVT, or overall mortality. CONCLUSION: The implementation of a selective routine DUS protocol was associated with significantly fewer in-hospital PE. More DVTs were identified with routine screening; however, surveillance bias appears to exist primarily with distal DVT. Larger trials are needed to further characterize the relationship between routine DUS screening and VTE outcomes in the high-risk trauma population. LEVEL OF EVIDENCE: Therapeutic/care management, level II.

Diagnosing deep vein thrombosis in cancer patients with suspected symptoms: An individual participant data meta-analysis.

BACKGROUND: A previous individual participant data (IPD) meta-analysis showed that the Wells rule and D-dimer testing cannot exclude suspected deep vein thrombosis (DVT) in cancer patients. OBJECTIVES: To explore reasons for this reduced diagnostic accuracy and to optimize the diagnostic pathway for cancer patients suspected of DVT. PATIENTS AND METHODS: Using IPD from 13 studies in patients with suspected DVT, DVT prevalence and the predictive value of the Wells rule items and D-dimer testing were compared between patients with and without cancer. Next, we developed a prediction model with five variables selected from all available diagnostic predictors. RESULTS: Among the 10 002 suspected DVT patients, there were 834 patients with cancer. The median prevalence of DVT in these patients with cancer was 37.5% (interquartile range [IQR], 30.8-45.5), whereas it was 15.1% (IQR, 11.5-16.7) in patients without cancer. Diagnostic performance of individual Wells rule items and D-dimer testing was similar across patients with and without cancer, except "immobility" and "history of DVT." The newly developed rule showed a pooled c-statistic 0.80 (95% confidence interval [CI], 0.75-0.83) and good calibration. However, using this model, still only 4.3% (95% CI, 3.0-5.7) of the suspected patients with cancer could be identified with a predicted DVT posttest probability of <2%. CONCLUSIONS: Likely because of the high prevalence of DVT, clinical models followed by D-dimer testing fail to rule out DVT efficiently in cancer patients suspected of DVT. Direct referral for compression ultrasonography appears to be the preferred approach for diagnosis of suspected DVT in cancer patients.

Effect of Low-Intensity vs Standard-Intensity Warfarin Prophylaxis on Venous Thromboembolism or Death Among Patients Undergoing Hip or Knee Arthroplasty: A Randomized Clinical Trial.

Importance: The optimal international normalized ratio (INR) to prevent venous thromboembolism (VTE) in warfarin-treated patients with recent arthroplasty is unknown. Objective: To determine the safety and efficacy of a target INR of 1.8 vs 2.5 for VTE prophylaxis after orthopedic surgery. Design, Setting, and Participants: The randomized Genetic Informatics Trial (GIFT) of Warfarin to Prevent Deep Vein Thrombosis enrolled 1650 patients aged 65 years or older initiating warfarin for elective hip or knee arthroplasty at 6 US medical centers. Enrollment began in April 2011 and follow-up concluded in October 2016. Interventions: In a 2 × 2 factorial design, participants were randomized to a target INR of 1.8 (n = 823) or 2.5 (n = 827) and to either genotype-guided or clinically guided warfarin dosing. For the first 11 days of therapy, open-label warfarin dosing was guided by a web application. Main Outcomes and Measures: The primary outcome was the composite of VTE (within 60 days) or death (within 30 days). Participants underwent screening duplex ultrasound postoperatively. The hypothesis was that an INR target of 1.8 would be noninferior to an INR target of 2.5, using a noninferiority margin of 3% for the absolute risk of VTE. Secondary end points were bleeding and INR values of 4 or more. Results: Among 1650 patients who were randomized (mean age, 72.1 years; 1049 women [63.6%]; 1502 white [91.0%]), 1597 (96.8%) received at least 1 dose of warfarin and were included in the primary analysis. The rate of the primary composite outcome of VTE or death was 5.1% (41 of 804) in the low-intensity-warfarin group (INR target, 1.8) vs 3.8% (30 of 793) in the standard-treatment-warfarin group (INR target, 2.5), for a difference of 1.3% (1-sided 95% CI, -∞ to 3.05%, P = .06 for noninferiority). Major bleeding occurred in 0.4% of patients in the low-intensity group and 0.9% of patients in the standard-intensity group, for a difference of -0.5% (95% CI, -1.6% to 0.4%). The INR values of 4 or more occurred in 4.5% of patients in the low-intensity group and 12.2% of the standard-intensity group, for a difference of -7.8% (95% CI, -10.5% to -5.1%). Conclusions and Relevance: Among older patients undergoing hip or knee arthroplasty and receiving warfarin prophylaxis, an international normalized ratio goal of 1.8 compared with 2.5 did not meet the criterion for noninferiority for risk of the composite outcome of VTE or death. However, the trial may have been underpowered to meet this criterion and further research may be warranted. Trial Registration: ClinicalTrials.gov Identifier: NCT01006733.

Apixaban for Routine Management of Upper Extremity Deep Venous Thrombosis (ARM-DVT): Methods of a prospective single-arm management study.

BACKGROUND: Upper extremity deep vein thrombosis (UEDVT) constitutes approximately 10% of all deep vein thromboses (DVTs). The incidence of UEDVT is increasing in association with use of peripherally inserted central venous catheters. Treatment for UEDVT is derived largely from evidence for treatment of lower extremity DVT. Limited evidence exists for the use of a direct oral anticoagulant for the treatment of UEDVT. POPULATION: Sequential patients identified within the Intermountain Healthcare System and University of Utah Healthcare system with symptomatic UEDVT defined as the formation of thrombus within the internal jugular, subclavian, axillary, brachial, ulnar, or radial veins of the arm. INTERVENTION: Apixaban 10 mg PO twice daily for 7 days followed by apixaban 5 mg twice daily for 11 weeks. COMPARISON: The historical literature review rate of venous thrombosis reported for recurrent clinically overt objective venous thromboembolism (VTE) and VTE-related death. If the confidence interval for the observed rate excludes the threshold event rate of 4%, we will conclude that treatment with apixaban is noninferior and therefore a clinically valid approach to treat UEDVT. SAMPLE SIZE: We elected a sample size of 375 patients so that an exact 95% confidence interval would exclude an event rate of VTE in the observation cohort of 4%. OUTCOME: Ninety-day rate of new or recurrent objectively confirmed symptomatic venous thrombosis and VTE-related death. The primary safety outcome is the composite of major and clinically relevant nonmajor bleeding.

Weight-based enoxaparin dosing and deep vein thrombosis in hospitalized trauma patients: A double-blind, randomized, pilot study.

BACKGROUND: Venous thromboembolism is a cause of morbidity and mortality in trauma patients. Chemoprophylaxis with low-molecular-weight heparin at a standardized dose is recommended. Conventional chemoprophylaxis may be inadequate. We hypothesized that a weight-adjusted enoxaparin prophylaxis regimen would reduce the frequency of venous thromboembolism in hospitalized trauma patients and at 90-day follow-up. METHODS: This prospective, randomized pilot study enrolled adult patients admitted to a level 1 trauma center between July 2013 and January 2015. Subjects were randomized to receive either standard (30 mg subcutaneously every 12 hours) or weight-based (0.5mg/kg subcutaneously every 12 hours) enoxaparin. Surveillance duplex ultrasound for lower extremity deep vein thrombosis was performed on hospital days 1, 3, and 7, and weekly thereafter. The primary outcome was deep vein thrombosis during hospitalization. Secondary outcomes included venous thromboembolism at 90 days and significant bleeding events. RESULTS: Two hundred thirty-four (124 standard, 110 weight-based) subjects were enrolled. There was no difference between standard and weight-based regarding age, body mass index, percentage female gender, injury severity score, or percentage that had surgery. There was a trend toward less in-hospital deep vein thrombosis in weight-based (12 [9.7%] standard vs 4 [3.6%] weight-based, P = .075). At 90 days, there was no difference in venous thromboembolism (12 [9.7%] standard vs 6 [5.5%] weight-based, P =.34). There was 1 bleeding event, which occurred in a standard subject. CONCLUSION: Weight-based enoxaparin dosing for venous thromboembolism chemoprophylaxis in trauma patients may provide better protection against venous thromboembolism than standard. A definitive study is necessary to determine whether weight-based dosing is superior to standard.

Postoperative Myocardial Injury and Inflammation Is Not Blunted by a Trial of Atorvastatin in Orthopedic Surgery Patients.

BACKGROUND: Orthopedic patients are at risk for adverse postoperative cardiovascular outcomes. QUESTIONS/PURPOSES: This pilot randomized controlled trial (RCT) of atorvastatin vs. placebo in orthopedic surgery patients was performed in order to assess: (1) the prevalence of perioperative myocardial injury; (2) the effect of atorvastatin on perioperative inflammation; and (3) the feasibility of performing a large RCT of statin therapy in orthopedic patients. METHODS: Hip fracture (hip Fx) and total hip and knee replacement (THR and TKR) patients were randomized 1:1 to atorvastatin 40 mg daily vs. placebo, starting preoperatively and continuing until postoperative day (POD) 45. High-sensitivity cardiac troponin I (hs-cTnI), high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 (IL-6) were measured preoperatively and on POD 2. Patients were monitored for adverse events until POD 90. RESULTS: Five hundred fifty-six patients were screened, 22 were recruited (4 hip Fx, 11 THR, 7 TKR), and 2 withdrew. Most (80%) had detectable hs-cTnI (> 1.1 pg/mL) preoperatively. Twenty percent had a perioperative rise in hs-cTnI (≥ 10 pg/mL), which was not blunted by atorvastatin. Hs-CRP rose in 19/20 patients, and IL-6 rose in all patients. However, atorvastatin did not blunt the rise in these inflammatory biomarkers. On POD 2, IL-6 and hs-cTnI levels correlated (ρ = 0.59, p = 0.02). Recruitment was limited by the high prevalence of statin use in the screened population and a high prevalence of exclusions among hip fracture patients. CONCLUSION: Perioperative myocardial injury and inflammation are common in orthopedic patients and do not appear to be reduced in those randomized to atorvastatin. TRIAL REGISTRATION: NCT02197065.

Patterns and Appropriateness of Thrombophilia Testing in an Academic Medical Center.

BACKGROUND: Clinical guidelines recommend against routine use of thrombophilia testing in patients with acute thromboembolism. Thrombophilia testing rarely changes acute management of a thrombotic event. OBJECTIVE: To determine appropriateness of thrombophilia testing in a teaching hospital. DESIGN: Retrospective cohort study. SETTING: One academic medical center in Utah. PARTICIPANTS: All patients who received thrombophilia testing between July 1, 2014, and December 31, 2014. MAIN MEASUREMENTS: Proportion of thrombophilia tests occurring in situations associated with minimal clinical utility, defined as tests meeting at least 1 of the following criteria: discharged before results available; test type not recommended; testing in situations associated with decreased accuracy; duplicate testing; and testing following a provoked thrombotic event. RESULTS: Overall, 163 patients received a total of 1451 thrombophilia tests for stroke (50% of tests; 35% of patients), venous thromboembolism (21% of tests; 21% of patients), and pregnancy-related conditions (15% of tests; 25% of patients). Of the 39 different test types performed, the most common were cardiolipin IgG and IgM antibodies (9% each), lupus anticoagulant (9%), and ß2-glycoprotein 1 IgG and IgM antibodies (8% each). In total, 911 tests (63%) were performed in situations associated with minimal clinical utility, with 126 patients (77%) receiving at least one such test. Only 2 patients (1%) had clear documentation of being offered genetic consultation. CONCLUSIONS: Thrombophilia testing in this single-center study was often associated with minimal clinical utility. Strategies to improve testing practices (eg, hematology specialty consult prior to inpatient testing, improved order panels) might help minimize inappropriate testing and promote value-driven care.

Electronic Alerts, Comparative Practitioner Metrics, and Education Improves Thromboprophylaxis and Reduces Thrombosis.

BACKGROUND: Venous thromboembolism chemoprophylaxis remains underutilized in hospitalized medical patients at high risk for venous thromboembolism. We assessed the effect of a health care quality-improvement initiative comprised of a targeted electronic alert, comparative practitioner metrics, and practitioner-specific continuing medical education on the rate of appropriate venous thromboembolism chemoprophylaxis provided to medical inpatients at high risk for venous thromboembolism. METHODS: We performed a multicenter prospective observational cohort study in an urban Utah hospital system. All medical patients admitted to 1 of 2 participating hospitals from April 1, 2010 to December 31, 2012 were eligible. Patients were members of the "control" (April 1, 2010 to December 31, 2010), "intervention" (January 1, 2011 to December 31, 2011), or "subsequent year" (January 1, 2012 to December 31, 2012) group. The primary outcome was the rate of appropriate chemoprophylaxis among patients at high risk for venous thromboembolism. Secondary outcomes included rates of symptomatic venous thromboembolism, major bleeding, all-cause mortality, heparin-induced thrombocytopenia, physician satisfaction, and alert fatigue. RESULTS: The rate of appropriate chemoprophylaxis among patients at high risk for venous thromboembolism increased (66.1% control period vs 81.0% intervention period vs 88.1% subsequent year; P <.001 for each comparison). A significant reduction of 90-day symptomatic venous thromboembolism accompanied the quality initiative (9.3% control period, 9.7% intervention period, 6.7% subsequent year; P = .009); 30-day venous thromboembolism rates also significantly decreased. CONCLUSIONS: A multifaceted intervention was associated with increased appropriate venous thromboembolism chemoprophylaxis among medical inpatients at high risk for venous thromboembolism and reduced symptomatic venous thromboembolism. The effect of the intervention was sustained.

Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report.

BACKGROUND: We update recommendations on 12 topics that were in the 9th edition of these guidelines, and address 3 new topics. METHODS: We generate strong (Grade 1) and weak (Grade 2) recommendations based on high- (Grade A), moderate- (Grade B), and low- (Grade C) quality evidence. RESULTS: For VTE and no cancer, as long-term anticoagulant therapy, we suggest dabigatran (Grade 2B), rivaroxaban (Grade 2B), apixaban (Grade 2B), or edoxaban (Grade 2B) over vitamin K antagonist (VKA) therapy, and suggest VKA therapy over low-molecular-weight heparin (LMWH; Grade 2C). For VTE and cancer, we suggest LMWH over VKA (Grade 2B), dabigatran (Grade 2C), rivaroxaban (Grade 2C), apixaban (Grade 2C), or edoxaban (Grade 2C). We have not changed recommendations for who should stop anticoagulation at 3 months or receive extended therapy. For VTE treated with anticoagulants, we recommend against an inferior vena cava filter (Grade 1B). For DVT, we suggest not using compression stockings routinely to prevent PTS (Grade 2B). For subsegmental pulmonary embolism and no proximal DVT, we suggest clinical surveillance over anticoagulation with a low risk of recurrent VTE (Grade 2C), and anticoagulation over clinical surveillance with a high risk (Grade 2C). We suggest thrombolytic therapy for pulmonary embolism with hypotension (Grade 2B), and systemic therapy over catheter-directed thrombolysis (Grade 2C). For recurrent VTE on a non-LMWH anticoagulant, we suggest LMWH (Grade 2C); for recurrent VTE on LMWH, we suggest increasing the LMWH dose (Grade 2C). CONCLUSIONS: Of 54 recommendations included in the 30 statements, 20 were strong and none was based on high-quality evidence, highlighting the need for further research.

Venous Thromboembolism in Critically Ill Medical Patients Receiving Chemoprophylaxis: A Focus on Obesity and Other Risk Factors.

PURPOSE: To compare the incidence of 90-day venous thromboembolism (VTE) in obese critically ill medical patients receiving VTE chemoprophylaxis with nonobese patients of similar illness severity. We also identified other VTE risk factors. METHODS: Eligible patients spent ≥24 hours in an intensive care unit between November 2007 and November 2013 and received VTE chemoprophylaxis within 48 hours of admission. The primary outcome was 90-day VTE. RESULTS: A total of 11 111 patients were evaluated, of which 1732 obese and 1831 nonobese patients were enrolled with mean BMIs of 38.9 ± 9.2 kg/m(2) and 24.5 ± 3.1 kg/m(2) and mean Acute Physiology and Chronic Health Evaluation II scores of 28.4 ± 11.8 and 26.6 ± 11.7, respectively. The rate of 90-day VTE for the total cohort, obese, and nonobese patients was 6.5%, 7.5%, and 5.5%, respectively. Obese patients were more likely to develop VTE compared with nonobese patients (odds ratio [OR]: 1.41; 95% confidence interval [CI]: 1.03 -1.93). Other risk factors significantly associated with 90-day VTE included prior VTE (OR: 3.93; 95% CI: 1.83-8.48), trauma with surgery in the previous 30 days (OR: 3.70; 95% CI: 1.39-9.86), central venous catheters (OR: 2.64; 95% CI: 1.87-3.72), surgery within 90 days (OR: 2.40; 95% CI: 1.61-3.58), mechanical ventilation (OR: 1.94; 95% CI: 1.39-2.71), male sex (OR: 1.55; 95% CI: 1.13-2.14), and increasing age using 1-year increments (OR: 1.02; 95% CI: 1.01 -1.03). CONCLUSIONS: The rate of VTE in critically ill medical patients remains high despite standard chemoprophylaxis. Obesity is among 8 risk factors independently associated with 90-day VTE.

D-dimer testing to select patients with a first unprovoked venous thromboembolism who can stop anticoagulant therapy: a cohort study.

BACKGROUND: Normal D-dimer levels after withdrawal of anticoagulant therapy are associated with a reduced risk for recurrence in patients with unprovoked venous thromboembolism (VTE) and may justify stopping treatment. OBJECTIVE: To determine whether patients with a first unprovoked VTE and negative D-dimer test result who stop anticoagulant therapy have a low risk for recurrence. DESIGN: Prospective management study with blinded outcome assessment. (ClinicalTrials.gov: NCT00720915). SETTING: 13 university-affiliated clinical centers. PATIENTS: 410 adults aged 75 years or younger with a first unprovoked proximal deep venous thrombosis or pulmonary embolism who had completed 3 to 7 months of anticoagulant therapy. INTERVENTION: Anticoagulant therapy was stopped if D-dimer test results were negative and was not restarted if results were still negative after 1 month. MEASUREMENTS: Recurrent VTE during an average follow-up of 2.2 years. RESULTS: In 319 patients (78%) who had 2 negative D-dimer results and did not restart anticoagulant therapy, rates of recurrent VTE were 6.7% (95% CI, 4.8% to 9.0%) per patient-year overall (42 of 319), 9.7% (CI, 6.7% to 13.7%) per patient-year in men (33 of 180), 5.4% (CI, 2.5% to 10.2%) per patient-year in women with VTE not associated with estrogen therapy (9 of 81), and 0.0% (CI, 0.0% to 3.0%) per patient-year in women with VTE associated with estrogen therapy (0 of 58) (P = 0.001 for the 3-group comparison). LIMITATIONS: Imprecision in female subgroups. Results may not be generalizable to different D-dimer assays from the one used in the study. CONCLUSION: The risk for recurrence in patients with a first unprovoked VTE who have negative D-dimer results is not low enough to justify stopping anticoagulant therapy in men but may be low enough to justify stopping therapy in women. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research.

Radiation and chest CT scan examinations: what do we know?

In the past 3 decades, the total number of CT scans performed has grown exponentially. In 2007, > 70 million CT scans were performed in the United States. CT scan studies of the chest comprise a large portion of the CT scans performed today because the technology has transformed the management of common chest diseases, including pulmonary embolism and coronary artery disease. As the number of studies performed yearly increases, a growing fraction of the population is exposed to low-dose ionizing radiation from CT scan. Data extrapolated from atomic bomb survivors and other populations exposed to low-dose ionizing radiation suggest that CT scan-associated radiation may increase an individual's lifetime risk of developing cancer. This finding, however, is not incontrovertible. Because this topic has recently attracted the attention of both the scientific community and the general public, it has become increasingly important for physicians to understand the cancer risk associated with CT scan and be capable of engaging in productive dialogue with patients. This article reviews the current literature on the public health debate surrounding CT scan and cancer risk, quantifies radiation doses associated with specific studies, and describes efforts to reduce population-wide CT scan-associated radiation exposure. CT scan examinations of the chest, including CT scan pulmonary and coronary angiography, high-resolution CT scan, low-dose lung cancer screening, and triple rule-out CT scan, are specifically considered.

Derivation and validation of a simple model to identify venous thromboembolism risk in medical patients.

BACKGROUND: Fewer than half of eligible hospitalized medical patients receive appropriate venous thromboembolism (VTE) prophylaxis. One reason for this low rate is the complexity of existing risk assessment models. A simple set of easily identifiable risk factors that are highly predictive of VTE among hospitalized medical patients may enhance appropriate thromboprophylaxis. METHODS: Electronic medical record interrogation was performed to identify medical admissions from January 1, 2000-December 31, 2007 (n=143,000), and those patients with objectively confirmed VTE during hospitalization or within 90 days following discharge. Putative risk factors most predictive of VTE were identified, and a risk assessment model (RAM) was derived; 46,000 medicine admissions from January 1, 2008-December 31, 2009 served as a validation cohort to test the predictive ability of the RAM. The newly derived RAM was compared with a published VTE assessment tool (Kucher Score). RESULTS: Four risk factors: previous VTE; an order for bed rest; peripherally inserted central venous catheterization line; and a cancer diagnosis, were the minimal set most predictive of hospital-associated VTE (area under the receiver operating characteristic curve [AUC]=0.874; 95% confidence interval [CI], 0.869-0.880). These risk factors upon validation in a separate population (validation cohort) retained an AUC=0.843; 95% CI, 0.833-0.852. The ability of the 4-element RAM to identify patients at risk of developing VTE within 90 days was superior to the Kucher Score. CONCLUSIONS: The 4-element RAM identified in this study may be used to identify patients at risk for VTE and improve rates of thromboprophylaxis. This simple and accurate RAM is an alternative to more complicated published VTE risk assessment tools that currently exist.

Risk of symptomatic DVT associated with peripherally inserted central catheters.

BACKGROUND: Previous studies undertaken to identify risk factors for peripherally inserted central catheter (PICC)-associated DVT have yielded conflicting results. PICC insertion teams and other health-care providers need to understand the risk factors so that they can develop methods to prevent DVT. METHODS: A 1-year prospective observational study of PICC insertions was conducted at a 456-bed, level I trauma center and tertiary referral hospital affiliated with a medical school. All patients with one or more PICC insertions were included to identify the incidence and risk factors for symptomatic DVT associated with catheters inserted by a facility-certified PICC team using a consistent and replicated approach for vein selection and insertion. RESULTS: A total of 2,014 PICCs were inserted during 1,879 distinct hospitalizations in 1,728 distinct patients for a total of 15,115 days of PICC placement. Most PICCs were placed in the right arm (76.9%) and basilic vein (74%) and were double-lumen 5F (75.3%). Of the 2,014 PICC insertions, 60 (3.0%) in 57 distinct patients developed DVT in the cannulated or adjacent veins. The best-performing predictive model for DVT (area under the curve, 0.83) was prior DVT (odds ratio [OR], 9.92; P < .001), use of double-lumen 5F (OR, 7.54; P < .05) or triple-lumen 6F (OR, 19.50; P < .01) PICCs, and prior surgery duration of > 1 h (OR, 1.66; P = .10). CONCLUSIONS: Prior DVT and surgery lasting > 1 h identify patients at increased risk for PICC-associated DVT. More importantly, increasing catheter size also is significantly associated with increased risk. Rates of PICC-associated DVT may be reduced by improved selection of patients and catheter size.

Risk of deep vein thrombosis following a single negative whole-leg compression ultrasound: a systematic review and meta-analysis.

CONTEXT: In patients with suspected lower extremity deep vein thrombosis (DVT), compression ultrasound (CUS) is typically the initial test to confirm or exclude DVT. Patients with an initial negative CUS result often require repeat CUS after 5 to 7 days. Whole-leg CUS may exclude proximal and distal DVT in a single evaluation. OBJECTIVE: To determine the risk of venous thromboembolism after withholding anticoagulation in patients with suspected lower extremity DVT following a single negative whole-leg CUS result. DATA SOURCES: MEDLINE, EMBASE, CINAHL, LILACS, Cochrane, and Health Technology Assessments databases were searched for articles published from January 1970 through November 2009. Supplemental searches were performed of Internet resources, reference lists, and by contacting content experts. STUDY SELECTION: Included studies were randomized controlled trials and prospective cohort studies of patients with suspected DVT and a negative whole-leg CUS result who did not receive anticoagulant therapy, and were followed up at least 90 days for venous thromboembolism events. DATA EXTRACTION: Two authors independently reviewed and extracted data regarding a single positive or negative whole-leg CUS result, occurrence of venous thromboembolism during follow-up, and study quality. RESULTS: Seven studies were included totaling 4731 patients with negative whole-leg CUS examinations who did not receive anticoagulation. Of these, up to 647 patients (13.7%) had active cancer and up to 725 patients (15.3%) recently underwent a major surgery. Most participants were identified from an ambulatory setting. Venous thromboembolism or suspected venous thromboembolism-related death occurred in 34 patients (0.7%), including 11 patients with distal DVT (32.4%); 7 patients with proximal DVT (20.6%); 7 patients with nonfatal pulmonary emboli (20.6%); and 9 patients (26.5%) who died, possibly related to venous thromboembolism. Using a random-effects model with inverse variance weighting, the combined venous thromboembolism event rate at 3 months was 0.57% (95% confidence interval, 0.25%-0.89%). CONCLUSION: Withholding anticoagulation following a single negative whole-leg CUS result was associated with a low risk of venous thromboembolism during 3-month follow-up.

Atypical calciphylaxis in a patient receiving warfarin then resolving with cessation of warfarin and application of hyperbaric oxygen therapy.

UNLABELLED: Calciphylaxis is a rare, usually fatal vasculopathic disorder characterized by cutaneous ischemia and necrosis due to calcification of arterioles. Although calciphylaxis is most frequently associated with end-stage renal disease (ESRD) and secondary hyperparathyroidism, it has been reported infrequently among patients on warfarin. No standard treatment has been established for atypical calciphylaxis; however, a potentially beneficial treatment is hyperbaric oxygen therapy (HBOT). A high degree of clinical suspicion, early diagnosis, and understanding the pathophysiology of this disease promotes the optimal management of this extremely morbid and often fatal condition. CASE REPORT: We present a 63-year-old Polynesian woman with biopsy-proven calciphylaxis in the absence of ESRD or elevated serum calcium levels while taking warfarin. Therapeutic dose enoxaparin was substituted for warfarin and she received 40 sessions of HBOT during which lower extremity ulcers resolved. DISCUSSION: Warfarin has been implicated when calciphylaxis presents in an atypical fashion. No guidelines exist for treatment of atypical calciphylaxis in the setting of concomitant warfarin therapy. Up to 80% of calciphylaxis patients die within 1 year of diagnosis. Our patient was changed to low-molecular-weight heparin and received HBOT. CONCLUSION: We present what we believe is the first case of atypical calciphylaxis thought to be attributable to warfarin treated with a therapeutic substitution of anticoagulant and HBOT leading to resolution of cutaneous lesions.