D-dimer Thresholds to Exclude Pulmonary Embolism among COVID-19 Patients in the Emergency Department: Derivation with Independent Validation.

OBJECTIVE: To derive and validate a D-dimer cutoff for ruling out pulmonary embolism (PE) in COVID-19 patients presenting to the emergency department (ED). METHODS: A retrospective cohort study was performed in an integrated healthcare system including 22 adult ED's between March 1, 2020, and January 31, 2021. Results were validated among patients enrolled in the RECOVER Registry, representing data from 154 ED's from 26 US states. Consecutive ED patients with laboratory confirmed COVID-19, a D-dimer performed within 48 h of ED arrival, and with objectively confirmed PE were compared to those without PE. After identifying a D-dimer threshold at which the 95% confidence lower bound of the negative predictive value for PE was higher than 98% in the derivation cohort, it was validated using RECOVER registry data. RESULTS: Among 3978 patients with a D-dimer result, 3583 with confirmed COVID-19 infection were included in the derivation cohort. Overall, PE incidence was 4.1% and a D-dimer cutoff of <2 µ/mL (2000 ng/mL) was associated with a NPV of 98.5% (95% CI = 98.0%-98.9%). In the validation cohort of 13,091 patients with a D-dimer, 7748 had confirmed COVID-19 infection, and the PE incidence was 1.14%. A D-dimer cutoff of <2 µ/mL was associated with a NPV of 99.5% (95% CI = 99.3%-99.7%). CONCLUSION: A D-dimer cutoff of <2 µ/ml was associated with a high negative predictive value for PE among patients with COVID-19. However, the resultant sensitivity for PE result at that threshold without pre-test probability assessment would be considered clinically unsafe.

Monotherapy Anticoagulation to Expedite Home Treatment of Patients Diagnosed With Venous Thromboembolism in the Emergency Department: A Pragmatic Effectiveness Trial.

BACKGROUND: The objective was to test if low-risk emergency department patients with vitamin K antagonist (venous thromboembolism [VTE]; including venous thrombosis and pulmonary embolism [PE]) can be safely and effectively treated at home with direct acting oral (monotherapy) anticoagulation in a large-scale, real-world pragmatic effectiveness trial. METHODS: This was a single-arm trial, conducted from 2016 to 2019 in accordance with the Standards for Reporting Implementation Studies guideline in 33 emergency departments in the United States. Participants had newly diagnosed VTE with low risk of death based upon either the modified Hestia criteria, or physician judgment plus the simplified PE severity index score of zero, together with nonhigh bleeding risk were eligible. Patients had to be discharged within 24 hours of triage and treated with either apixaban or rivaroxaban. Effectiveness was defined by the primary efficacy and safety outcomes, image-proven recurrent VTE and bleeding requiring hospitalization >24 hours, respectively, with an upper limit of the 95% CI for the 30-day frequency of VTE recurrence below 2.0% for both outcomes. RESULTS: We enrolled 1421 patients with complete outcomes data, including 903 with venous thrombosis and 518 with PE. The recurrent VTE requiring hospitalization occurred in 14/1421 (1.0% [95% CI, 0.5%-1.7%]), and bleeding requiring hospitalization occurred in 12/1421 (0.8% [0.4%-1.5%). The rate of severe bleeding using International Society for Thrombosis and Haemostasis criteria was 2/1421 (0.1% [0%-0.5%]). No patient died, and serious adverse events occurred in 2.5% of venous thrombosis patients and 2.3% of patients with PE. Medication nonadherence was reported by patients in 8.0% (6.6%-9.5%) and was associated with a risk ratio of 6.0 (2.3-15.2) for VTE recurrence. Among all patients diagnosed with VTE in the emergency department during the period of study, 18% of venous thrombosis patients and 10% of patients with PE were enrolled. CONCLUSIONS: Monotherapy treatment of low-risk patients with venous thrombosis or PE in the emergency department setting produced a low rate of bleeding and VTE recurrence, but may be underused. Patients with venous thrombosis and PE should undergo risk-stratification before home treatment. Improved patient adherence may reduce rate of recurrent VTE. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03404635.

Randomized Trial of Therapy Dogs Versus Deliberative Coloring (Art Therapy) to Reduce Stress in Emergency Medicine Providers.

OBJECTIVE: Cognitive stress during shift work contributes to burnout in emergency department (ED) workers. We hypothesize that if physicians and nurses interact with a therapy dog for 5 minutes while on ED shift, both their perceived and their manifested stress levels will decrease. METHODS: In this single-center, prospective, randomized controlled clinical trial (NCT03628820), we tested the effectiveness of therapy dogs versus coloring a mandala and versus no intervention (control) on provider stress. Consenting emergency medicine physicians and nurses provided three self-reported assessments of stress and saliva samples at the start (T1), at the middle (T2), and near the end (T3) of shift. Thirty minutes prior to T2, participants were randomized to either interacting with a therapy dog or coloring for 5 minutes; controls had neither. Stress was assessed on visual analog scale (VAS, 0-100 mm) and with salivary cortisol (Salimetrics) and the modified Perceived Stress Scale (mPSS-10). To assess potential change in participant behavior, patients of providers in either group were asked to complete an internally derived survey of empathic behaviors displayed by providers at T1 and T3. RESULTS: We enrolled 122 providers (n = 39 control, n = 40 coloring, n = 43 dog); 48% were residents, and 60% enrolled on an evening shift. At T1, mean (±SD) VAS score was not different between groups (18.2 [±17.8] mm). At T3, VAS tended to increase with coloring (24.5 mm), remain unchanged in controls (20 mm), and decreased slightly with dogs (13.6 mm, p = 0.018 vs. coloring, Tukey's post hoc). Salivary cortisol levels were consistently highest at the beginning of each providers' shift and were significantly decreased versus control in both the dog and the coloring groups (p < 0.05, Tukey's). We observed no difference between groups for the mPSS-10 nor in patient reported survey of empathic behaviors. CONCLUSION: This randomized controlled clinical trial demonstrates preliminary evidence that a 5-minute therapy dog interaction while on shift can reduce provider stress in ED physicians and nurses.

Controlled clinical trial of canine therapy versus usual care to reduce patient anxiety in the emergency department.

OBJECTIVE: Test if therapy dogs reduce anxiety in emergency department (ED) patients. METHODS: In this controlled clinical trial (NCT03471429), medically stable, adult patients were approached if the physician believed that the patient had "moderate or greater anxiety." Patients were allocated on a 1:1 ratio to either 15 min exposure to a certified therapy dog and handler (dog), or usual care (control). Patient reported anxiety, pain and depression were assessed using a 0-10 scale (10 = worst). Primary outcome was change in anxiety from baseline (T0) to 30 min and 90 min after exposure to dog or control (T1 and T2 respectively); secondary outcomes were pain, depression and frequency of pain medication. RESULTS: Among 93 patients willing to participate in research, 7 had aversions to dogs, leaving 86 (92%) were willing to see a dog six others met exclusion criteria, leaving 40 patients allocated to each group (dog or control). Median and mean baseline anxiety, pain and depression scores were similar between groups. With dog exposure, median anxiety decreased significantly from T0 to T1: 6 (IQR 4-9.75) to T1: 2 (0-6) compared with 6 (4-8) to 6 (2.5-8) in controls (P<0.001, for T1, Mann-Whitney U and unpaired t-test). Dog exposure was associated with significantly lower anxiety at T2 and a significant overall treatment effect on two-way repeated measures ANOVA for anxiety, pain and depression. After exposure, 1/40 in the dog group needed pain medication, versus 7/40 in controls (P = 0.056, Fisher's exact test). CONCLUSIONS: Exposure to therapy dogs plus handlers significantly reduced anxiety in ED patients.

Emergency Department Discharge of Pulmonary Embolus Patients.

BACKGROUND: Hospitalization for low-risk pulmonary embolism (PE) is common, expensive, and of questionable benefit. OBJECTIVE: The objective was to determine if low-risk PE patients discharged from the emergency department (ED) on rivaroxaban require fewer hospital days compared to standard of care (SOC). METHODS: Multicenter, open-label randomized trial in low-risk PE defined by Hestia criteria. Adult subjects were randomized to early ED discharge on rivaroxaban or SOC. Primary outcome was total number of initial hospital hours, plus hours of hospitalization for bleeding or venous thromboembolism (VTE), 30 days after randomization. A 90-day composite safety endpoint was defined as major bleeding, clinically relevant nonmajor bleeding, and mortality. RESULTS: Of 114 randomized subjects, 51 were early discharge and 63 were SOC. Of 112 (98.2%) receiving at least one dose of study drug, 99 (86.8%) completed the study. Initial hospital LOS was 4.8 hours versus 33.6 hours, with a mean difference of -28.8 hours (95% confidence interval [CI] = -42.55 to -15.12 hours) for early discharge versus SOC, respectively. At 90 days, mean total hospital days (for any reason) were less for early discharge than SOC, 19.2 hours versus 43.2 hours, with a mean difference of 26.4 hours (95% CI = -46.97 to -3.34 hours). At 90 days, there were no bleeding events, recurrent VTE, or deaths. The composite safety endpoint was similar in both groups, with a difference in proportions of 0.005 (95% CI = -0.18 to 0.19). Total costs were $1,496 for early discharge and $4,234 for SOC, with a median difference of $2,496 (95% CI = -$2,999 to -$2,151). CONCLUSIONS: Low-risk ED PE patients receiving early discharge on rivaroxaban have similar outcomes to SOC, but fewer total hospital days and lower costs over 30 days.

Comparison of outcomes in patients with intracranial hemorrhage on factor Xa inhibitors versus vitamin K antagonists treated with 4-factor prothrombin complex concentrate.

The relative clinical efficacy of 4-factor prothrombin complex concentrate (4F-PCC) in oral anticoagulant-associated intracranial hemorrhage is unknown, especially for factor Xa-inhibiting anticoagulants. We report short-term outcomes of patients with oral anticoagulant-associated intracranial hemorrhage on vitamin K antagonists and factor Xa inhibitors who were treated with 4F-PCC. This multicenter, observational study involved patients presenting to the emergency department in nine hospitals in an integrated health care delivery system in Texas between July 2013 and December 2015. Forty-two patients diagnosed with oral anticoagulant-associated intracranial hemorrhage-24 taking a vitamin K antagonist and 14 taking a factor Xa inhibitor-were treated with 4F-PCC as part of usual care. Study patients had similar baseline demographics, with the exception of suspected etiology of hemorrhage. Outcomes of the vitamin K antagonist group were similar to those of the factor Xa inhibitor group, with no significant differences in overall in-hospital mortality (32.1% vs 14.2%, respectively), length of stay, or rates of hemorrhagic expansion, thromboembolism, or discharge to home. In conclusion, this small sample of patients with oral factor Xa inhibitor and vitamin K antagonist-associated intracranial hemorrhage treated with 4F-PCC had similar mortality and neurological outcomes, with no venous thromboembolic events.

Immediate Discharge and Home Treatment With Rivaroxaban of Low-risk Venous Thromboembolism Diagnosed in Two U.S. Emergency Departments: A One-year Preplanned Analysis.

OBJECTIVES: The study hypothesis was that a target-specific anticoagulant would allow successful home treatment of selected patients with deep vein thrombosis (DVT) and pulmonary embolism (PE) diagnosed in two urban emergency departments (EDs). METHODS: A protocol was established for treating low-risk DVT or PE patients with rivaroxaban and clinic, follow-up at both 2 to 5 weeks, and 3 to 6 months. Patients were determined to be low-risk by using a modified version of the Hestia criteria, supplemented by additional criteria for patients with active cancer. Acceptable outcome rates were defined as venous thromboembolism (VTE) recurrence ≤ 2.1% or bleeding ≤ 9.4% during treatment. VTE recurrence required positive imaging of any VTE. The International Society of Thrombosis and Hemostasis definition of major or clinically relevant nonmajor bleeding was used. RESULTS: From March 2013 through April 2014, a total of 106 patients were treated. Seventy-one (68%) had DVT, 30 (28%) had PE, and five (3%) had both, representing 51% of all DVTs and 27% of all PEs diagnosed in both EDs during the period of study. The 106 patients have been followed for a mean (±SD) of 389 (±111) days (range = 213 to 594 days). No patient had VTE recurrence, and no patient had a major or clinically relevant bleeding event while on therapy (none of the 106, 0%, 95% confidence interval [CI] = 0% to 3.4%). However, three patients 2.8% (95% CI = 1% to 8%) had recurrent DVT after cessation of therapy. CONCLUSIONS: Patients diagnosed with VTE and immediately discharged from the ED while treated with rivaroxaban had a low rate of VTE recurrence and bleeding.

Cost of Treating Venous Thromboembolism With Heparin and Warfarin Versus Home Treatment With Rivaroxaban.

BACKGROUND: Target-specific anticoagulants such as rivaroxaban facilitate immediate discharge of low-risk venous thromboembolism (VTE; including deep vein thrombosis [DVT] and pulmonary embolism [PE]) allowing treatment at home instead of hospitalization. OBJECTIVES: The objective was to compare costs accrued over 6 months by patients diagnosed with low-risk VTE and treated at home with rivaroxaban versus usual care with heparin-warfarin. METHODS: This case-control study calculated costs using the established charge-to-cost ratio from UB-04 billing claims of patients diagnosed at two metropolitan hospitals. Patients were defined as low risk by the Hestia criteria. All patients were anticoagulated for 6 months. Control patients were treated with usual care using low-molecular-weight heparin (LMWH) and then warfarin. Case patients were treated with an initial dose of rivaroxaban in the ED followed by same-day discharge home with rivaroxaban. Medians were compared by Mann-Whitney U-test. RESULTS: Fifty cases and 47 controls were identified. Groups were well matched according to mean age, Charlson comorbidity score, and proportions by sex and location of thrombus. For all VTEs, median hospital charges for 6 months after diagnosis were $11,128 (interquartile range [IQR] = $8,110 to $23,390) for controls, compared with $4,787 (IQR = $3,042 to $7,596) for cases (Mann-Whitney U-test p < 0.001). Subgroup analyses of the first week of therapy, PE, DVT, and inpatient pharmacy costs retained significance, with costs for rivaroxaban-treated PE patients 57% lower than control PE patients (p < 0.001) and 56% lower for DVT patients (p = 0.003). CONCLUSIONS: Cost of medical care was lower for low-risk VTE patients discharged immediately from the ED with rivaroxaban therapy compared with patients treated with LMWH-warfarin.

A soluble guanylate cyclase stimulator, BAY 41-8543, preserves right ventricular function in experimental pulmonary embolism.

Pulmonary embolism (PE) increases pulmonary vascular resistance, causing right ventricular (RV) dysfunction, and poor clinical outcome. Present studies test if the soluble guanylate cyclase stimulator BAY 41-8543 reduces pulmonary vascular resistance and protects RV function. Experimental PE was induced in anesthetized, male Sprague-Dawley rats by infusing 25 µm polystyrene microspheres (1.95 million/100 g body wt, right jugular vein) producing moderate PE. Pulmonary artery vascular resistance, estimated as RVPSP/CO, increased 3-fold after 5 h of PE. Treatment with BAY 41-8543 (50 µg/kg, I.V.; given at the time of PE induction) normalized this index by reducing RVPSP and markedly increasing CO, via preservation of heart rate and stroke volume. Ex vivo RV heart function showed minimal changes at 5 h of PE, but decreased significantly after 18 h of PE, including peak systolic pressure (PSP, Control 39 ± 1 mmHg vs. 19 ± 3 PE), +dP/dt (1192 ± 93 mmHg/s vs. 444 ± 64) and -dP/dt (-576 ± 60 mmHg/s vs. -278 ± 40). BAY 41-8543 significantly improved all three indices of RV heart function (PSP 35 ± 3.5, +dP/dt 1129 ± 100, -dP/dt -568 ± 87). Experimental PE produced increased PVR and RV dysfunction, which were ameliorated by treatment with BAY 41-8543. Thus, there is vasodilator reserve in this model of experimental PE that can be exploited to reduce the stress upon the heart and preserve RV contractile function.

Pulmonary vascular reserve during experimental pulmonary embolism: effects of a soluble guanylate cyclase stimulator, BAY 41-8543.

OBJECTIVES: Pulmonary embolism causes pulmonary hypertension by mechanical obstruction and vasoconstriction. Therapeutic potential of pharmacologic dilation of unblocked vessels has received limited attention. We tested pulmonary vasodilator reserve using a soluble guanylate cyclase stimulator, BAY 41-8543. DESIGN: Controlled animal study. SETTING: Medical center research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Pulmonary embolism was induced by infusing 25-µm plastic microspheres in the right jugular vein, producing mild or moderate pulmonary hypertension. Control animals with no pulmonary embolism received suspension medium for microspheres. MEASUREMENTS AND MAIN RESULTS: Mild pulmonary embolism increased right ventricular peak systolic pressure (from 28 to 38 mm Hg) and decreased cardiac output (from 46 to 34 mL/min) with no change in mean arterial pressure. Infusion of BAY 41-8543 (50-200 µg/kg) decreased right ventricular peak systolic pressure. Five hrs moderate pulmonary embolism increased right ventricular peak systolic pressure (from 28 to 47 mm Hg) and decreased cardiac output (from 48 to 27 mL/min), causing right ventricular peak systolic pressure/cardiac output to increase from 0.6 control with no pulmonary embolism to 1.8 mm Hg/mL/min in 5-hr moderate pulmonary embolism + solvent for BAY 41-8543. Treatment of 5-hr moderate pulmonary embolism with BAY 41-8543 (50 µg/kg) caused a 2.2-fold increase in cardiac output (59 mL/min) with a 46% reduction in right ventricular peak systolic pressure (38 mm Hg), suggesting significant pulmonary vasodilation. Moderate pulmonary embolism decreased arterial sO2 (from 83% to 71%) and increased lactate (from 0.5 to 2.3 mmol/L). Treatment with BAY 41-8543 normalized sO2 and lactate. Hemolysis occurred during moderate experimental pulmonary embolism (60-fold increase in plasma hemoglobin). Treatment with BAY 41-8543 reduced free plasma hemoglobin content by 80%. CONCLUSIONS: In the setting of moderate impervious pulmonary embolism, treatment with a guanylate cyclase stimulator normalized pulmonary hemodynamics, reduced hemolysis, and improved oxygenation. These data support the hypothesis that pharmacologic dilation of nonobstructed pulmonary vasculature can effectively treat acute pulmonary hypertension from pulmonary embolism.

Up-regulation of arginase II contributes to pulmonary vascular endothelial cell dysfunction during experimental pulmonary embolism.

Pulmonary embolism (PE) causes pulmonary hypertension by mechanical obstruction and constriction of non-obstructed vasculature. We tested if experimental PE impairs pulmonary vascular endothelium-dependent dilation via activation of arginase II. Experimental PE was induced in male Sprague-Dawley rats by infusing 25 µm microspheres in the right jugular vein, producing moderate pulmonary hypertension. Shams received vehicle injection. Pulmonary arterial rings were isolated after 18 h and isometric tensions were determined. Dilations were induced with acetylcholine, calcium ionophore A23187 or nitroglycerin (NTG) in pre-contracted rings (phenylephrine). Protein expression was assessed by Western blot and immunohistochemistry. Arginase activity was inhibited by intravenous infusion of N(w)-hydroxy-nor-l-arginine (nor-NOHA). l-Arginine supplementation was also given. Endothelium-dependent dilation responses were significantly reduced in PE vs. vehicle-treated animals (ACh: 50 ± 9% vs. 93 ± 3%; A23187: 19 ± 7% vs. 85 ± 7%, p < 0.05), while endothelium-independent dilations (NTG) were unchanged. Endothelial nitric oxide synthase (eNOS) protein content was unchanged by PE. Expression of arginase II increased 4.5-fold and immunohistochemistry revealed increased arginase II staining. Nor-NOHA treatment and l-arginine supplementation significantly improved pulmonary artery ring endothelium-dependent dilation in PE (ACh: 58 ± 6% PE, 88 ± 6% PE + nor-NOHA, 84 ± 4% PE + l-arginine). Experimental PE impairs endothelium-dependent pulmonary artery dilation, while endothelium-independent dilation remains unchanged. The data support the conclusion that up-regulation of arginase II protein expression contributes to pulmonary artery endothelial dysfunction in this model of experimental PE.