Distribution and bulk flow analyses of the intraflagellar transport (IFT) motor kinesin-2 support an "on-demand" model for Chlamydomonas ciliary length control.

Most cells tightly control the length of their cilia. The regulation likely involves intraflagellar transport (IFT), a bidirectional motility of multi-subunit particles organized into trains that deliver building blocks into the organelle. In Chlamydomonas, the anterograde IFT motor kinesin-2 consists of the motor subunits FLA8 and FLA10 and the nonmotor subunit KAP. KAP dissociates from IFT at the ciliary tip and diffuses back to the cell body. This observation led to the diffusion-as-a-ruler model of ciliary length control, which postulates that KAP is progressively sequestered into elongating cilia because its return to the cell body will require increasingly more time, limiting motor availability at the ciliary base, train assembly, building block supply, and ciliary growth. Here, we show that Chlamydomonas FLA8 also returns to the cell body by diffusion. However, more than 95% of KAP and FLA8 are present in the cell body and, at a given time, just ~1% of the motor participates in IFT. After repeated photobleaching of both cilia, IFT of fluorescent kinesin subunits continued indicating that kinesin-2 cycles from the large cell-body pool through the cilia and back. Furthermore, growing and full-length cilia contained similar amounts of kinesin-2 subunits and the size of the motor pool at the base changed only slightly with ciliary length. These observations are incompatible with the diffusion-as-a-ruler model, but rather support an "on-demand model," in which the cargo load of the trains is regulated to assemble cilia of the desired length.

Revascularization for claudication: Changing the natural history of a benign disease!

OBJECTIVE: The benign natural history of intermittent claudication was first documented in 1960 and has been reconfirmed in several subsequent studies. Excellent outcomes in patients with intermittent claudication can be achieved with exercise therapy and optimal medical management. Professional society guidelines have clearly stated that revascularization procedures should be performed only in patients with incapacitating claudication who have failed conservative therapy. Despite these guidelines, revascularization procedures, primarily percutaneous interventions, have been increasingly utilized in patients with claudication. Many of these patients are not even offered an attempt at medical therapy, and those who are often do not undergo a full course of treatment. Many studies document significant reintervention rates following revascularization, which are associated with increased rates of acute and chronic limb ischemia that may result in significant rates of amputation. The objectives of this study were to compare outcomes of conservative therapy to those seen in patients undergoing revascularization procedures and to determine the impact of revascularization on the natural history of claudication. METHODS: Google Scholar and PubMed were searched for manuscripts on the conservative management of claudication and for those reporting outcomes following revascularization for claudication. RESULTS: Despite early improvement in claudication symptoms following revascularization, multiple studies have demonstrated that long-term outcomes following revascularization are often no better than those obtained with conservative therapy. High reintervention rates (up to 43% for tibial atherectomies) result in high rates of both acute and chronic limb ischemia as compared with those patients undergoing medical therapy. In addition, amputation rates as high as 11% on long-term follow-up are seen in patients undergoing early revascularization. These patients also have a higher incidence of adverse cardiovascular events such as myocardial infarctions compared with patients treated medically. CONCLUSIONS: Revascularization procedures negatively impact the natural history of claudication often resulting in multiple interventions, an increase in the incidence of acute and chronic limb ischemia, and an increased risk of amputation. Accordingly, informed consent requires that all patients undergoing early revascularization must be appraised of the potential negative impact of revascularization on the natural history of claudication.

Piloting a Layperson Prehospital Care System in Rural Uganda.

INTRODUCTION: In many low-income countries, basic prehospital Emergency Medical Services (EMS) remain under-developed, resulting in significant delays or the complete inability to access care. STUDY OBJECTIVE: The purpose of this study was to analyze the effectiveness of a layperson EMS training targeting motorcycle taxi (boda) drivers in a rural region of Uganda. METHODS: Fifty (50) adult boda drivers from Masindi, Uganda were selected for a one-day training course including lectures and simulation. Course content covered basic prehospital skills and transport. Participants were given a first responder kit at completion of the course. Understanding of material was assessed prior to training, immediately after course completion, and four months from the initial course using the same ten question test. Test means were analyzed using a standard linear regression model. At the four-month follow up, all 50 boda drivers participated in semi-structured small group qualitative interviews regarding their perception of the course and experiences implementing course skills in the community. Boda drivers were asked to complete a brief form on each patient transported during the study period. For patients transported to Masindi Kitara Medical Center (MKMC), hospital trauma registry data were analyzed. RESULTS: Trainees showed both knowledge acquisition and retention with pre-test scores of 21.8% improving to 48.0% at course completion and 57.7% at the four-month follow up. Overall, participant's scores increased by an average of 35% from the pre-test to the second post-test (P <.001). A total of 69 patient forms were completed on transported patients over the initial four-month period. Ninety-five percent (95%) of these were injured patients, and motorcycle crash was the predominant mechanism of injury (48% of injuries). Eight patients were transported to MKMC, but none of these patients were recorded in the hospital trauma registry. Major barriers identified through semi-structured interviews included harassment by police, poor road conditions, and lack of basic resources for transport. Ninety-four percent (94%) of trainees strongly agreed that the training was useful. Total costs were estimated at $3,489 USD, or $69 per trainee. CONCLUSION: Motorcycle taxi drivers can be trained to provide basic prehospital care in a short time and at a low cost. While there is much enthusiasm for additional training and skill acquisition from this cohort, the sustainability and scalability of such programs is still in question.

The Challenge of Intermediate-Risk Pulmonary Embolism.

BACKGROUND: Intermediate-risk pulmonary embolism is a common disease that is associated with significant morbidity and mortality; however, a standardized treatment protocol is not well-established. AREAS OF UNCERTAINTY: Treatments available for intermediate-risk pulmonary embolisms include anticoagulation, systemic thrombolytics, catheter-directed therapies, surgical embolectomy, and extracorporeal membrane oxygenation. Despite these options, there is no clear consensus on the optimal indication and timing of these interventions. THERAPEUTIC ADVANCES: Anticoagulation remains the cornerstone of treatment for pulmonary embolism; however, over the past 2 decades, there have been advances in the safety and efficacy of catheter-directed therapies. For massive pulmonary embolism, systemic thrombolytics and, sometimes, surgical thrombectomy are considered first-line treatments. Patients with intermediate-risk pulmonary embolism are at high risk of clinical deterioration; however, it is unclear whether anticoagulation alone is sufficient. The optimal treatment of intermediate-risk pulmonary embolism in the setting of hemodynamic stability with right heart strain present is not well-defined. Therapies such as catheter-directed thrombolysis and suction thrombectomy are being investigated given their potential to offload right ventricular strain. Several studies have recently evaluated catheter-directed thrombolysis and embolectomies and demonstrated the efficacy and safety of these interventions. Here, we review the literature on the management of intermediate-risk pulmonary embolisms and the evidence behind those interventions. CONCLUSIONS: There are many treatments available in the management of intermediate-risk pulmonary embolism. Although the current literature does not favor 1 treatment as superior, multiple studies have shown growing data to support catheter-directed therapies as potential options for these patients. Multidisciplinary pulmonary embolism response teams remain a key feature in improving the selection of advanced therapies and optimization of care.

Multi-Influenza HA Subtype Protection of Ferrets Vaccinated with an N1 COBRA-Based Neuraminidase.

The influenza neuraminidase (NA) is a promising target for next-generation vaccines. Protection induced by vaccination with the computationally optimized broadly reactive NA antigen (N1-I COBRA NA) was characterized in both influenza serologically naive and pre-immune ferret models following H1N1 (A/California/07/2009, CA/09) or H5N1 (A/Vietnam/1203/2004, Viet/04) influenza challenges. The N1-I COBRA NA vaccine elicited antibodies with neutralizing ELLA activity against both seasonal and pandemic H1N1 influenza, as well as the H5N1 influenza virus. In both models, N1-I COBRA NA-vaccinated ferrets that were challenged with CA/09 virus had similar morbidity (weight loss and clinical symptoms) as ferrets vaccinated with the CA/09 HA control vaccine. There were significantly reduced viral titers compared to the mock-vaccinated control animals. Ferrets vaccinated with N1-I COBRA NA or Viet/04 NA vaccines were protected against the H5N1 virus infection with minimal clinical symptoms and negligible weight loss. In contrast, ferrets vaccinated with the CA/09 NA vaccine lost ~10% of their original body weight with 25% mortality. Vaccination with either HA or NA vaccines did not inhibit contact transmission of CA/09 virus to naïve cage mates. Overall, the N1-I COBRA vaccine elicited protective immune responses against both H1N1 and H5N1 infections and partially mitigated disease in contact-transmission receiving ferrets. These results indicate that the N1-I COBRA NA performed similarly to the CA/09 HA and NA positive controls. Therefore, the N1-I COBRA NA alone induces protection against viruses from both H5N1 and H1N1 subtypes, indicating its value as a vaccine component in broadly protective influenza vaccines.

Implementation of Novel Lipid Therapies in a Refractory Heterozygous Familial Hypercholesterolemia Patient With Atherosclerotic Disease.

Compound heterozygous familial hypercholesterolemia patients are phenotypically similar to homozygous familial hypercholesterolemia patients, present with significant elevations of low-density lipoprotein cholesterol, and are at risk of cardiovascular disease. Although new treatment options are emerging, the stepwise approach to the use of different therapies has not been well described. (Level of Difficulty: Intermediate.).

Use of Nicergoline as Adjunctive Treatment of Neurotrophic Keratitis in Routine Clinical Practice: A Case Series.

PURPOSE: To describe the effectiveness and safety of nicergoline in patients with epithelial corneal defect or corneal ulcer due to neurotrophic keratitis (NK). METHODS: A prospective case series review was performed in 14 patients with NK who started treatment with nicergoline as an off-label prescription from January to November 2020. Patients with a epithelial defect or corneal ulcer due to NK were treated with oral nicergoline. RESULTS/SERIAL CASES: Complete corneal healing was observed in 10 (71.4%) of the 14 patients after 25.6 ± 26.60 days (range 7-90) with nicergoline. In three (21.5%) patients wound healing was not achieved, and one patient (7.1%) was lost to follow-up. The mean time between diagnosis and the starting of nicergoline was 10.92 ± 8.85 days (0-28). No adverse effects of nicergoline were observed. CONCLUSION: Nicergoline as an adjunctive treatment for NK showed a potential use in the healing of epithelial defect in real-life clinical practice.

Visual impairment induced by prosthetic cobaltism.

The case of a 68-year-old patient with visual loss secondary to prosthetic cobaltism is reported. The degeneration of the metallic hip prosthesis can produce a systemic absorption of cobalt with cardiac, neurological, endocrine, auditory, and visual manifestations. The diagnostic suspicion is confirmed by serum cobalt measurements. Treatment with early surgery and chelating agents can lead to improvement of the visual, and the other disorders.

Universal Influenza Virus Neuraminidase Vaccine Elicits Protective Immune Responses against Human Seasonal and Pre-pandemic Strains.

The hemagglutinin (HA) surface protein is the primary immune target for most influenza vaccines. The neuraminidase (NA) surface protein is often a secondary target for vaccine designs. In this study, computationally optimized broadly reactive antigen (COBRA) methodology was used to generate the N1-I NA vaccine antigen that was designed to cross-react with avian, swine, and human influenza viruses of the N1 NA subtype. The elicited antibodies bound to NA proteins derived from A/California/07/2009 (H1N1)pdm09, A/Brisbane/59/2007 (H1N1), A/Swine/North Carolina/154074/2015 (H1N1), and A/Viet Nam/1203/2004 (H5N1) influenza viruses, with NA-neutralizing activity against a broad panel of HXN1 influenza strains. Mice vaccinated with the N1-I COBRA NA vaccine were protected from mortality and viral lung titers were lower when challenged with four different viral challenges (A/California/07/2009, A/Brisbane/59/2007, A/Swine/North Carolina/154074/2015, and A/Viet Nam/1203/2004). Vaccinated mice had little to no weight loss against both homologous, but also cross-NA, genetic clade challenges. Lung viral titers were lower than the mock-vaccinated mice and, at times, equivalent to the homologous control. Thus, the N1-I COBRA NA antigen has the potential to be a complementary component in a multiantigen universal influenza virus vaccine formulation that also contains HA antigens. IMPORTANCE The development and distribution of a universal influenza vaccine would alleviate global economic and public health stress from annual influenza virus outbreaks. The influenza virus NA vaccine antigen allows for protection from multiple HA subtypes and virus host origins, but it has not been the focus of vaccine development. The N1-I NA antigen described here protected mice from direct challenge of four distinct influenza viruses and inhibited the enzymatic activity of an N1 influenza virus panel. The use of the NA antigen in combination with the HA antigen widens the breadth of protection against various virus strains. Therefore, this research opens the door to the development of a longer-lasting vaccine with increased protective breadth.

Afectación visual por cobaltismo protésico / Visual impairment induced by prosthetic cobaltism

Se presenta el caso de un paciente de 68 años con pérdida visual secundaria a cobaltismo protésico. La degeneración de la prótesis metálica de cadera produce una absorción sistémica de cobalto con manifestaciones cardíacas, neurológicas, endocrinas, auditivas y visuales. La sospecha diagnóstica es confirmada mediante determinaciones séricas de cobalto, y un tratamiento con cirugía precoz y agentes quelantes puede generar una mejoría visual y del resto de síntomas (AU)

The case of a 68-year-old patient with visual loss secondary to prosthetic cobaltism is reported. The degeneration of the metallic hip prosthesis can produce a systemic absorption of cobalt with cardiac, neurological, endocrine, auditory, and visual manifestations. The diagnostic suspicion is confirmed by serum cobalt measurements. Treatment with early surgery and chelating agents can lead to improvement of the visual, and the other disorders (AU)

Trends in corneal transplantation in a single center in Barcelona, Spain. Transitioning to DMEK.

PURPOSE: To observe trends in surgical techniques for corneal transplantation and main indications in our hospital over the past five years. METHODS: Retrospective descriptive study, including all keratoplasties performed at the Hospital Clinic of Barcelona, Spain, between January 2014 and December 2018. RESULTS: In total, 332 keratoplasties were performed. In total, 127 (38.25%) were penetrating keratoplasties (PK), and 205 (61.75%) were lamellar keratoplasties (LK). In 2014, a total of 48 keratoplasties were carried-out, whereas in 2018, the total was 93, which represents a 93.75% increase in corneal transplantation surgeries. Eye bank-delivered precut tissue for DMEK was introduced in 2016, and 3 cases (6.25%), were carried out that year. In 2018, DMEK became the leading technique with 56 cases (60.22%). Fuchs' dystrophy was the leading indication for corneal transplant (37.63%) in 2018. CONCLUSION: Introduction of DMEK in a single center can be implemented in a relatively short period of time, becoming the most popular surgical procedure in corneal transplantation. A possible factor encouraging this change is the availability of eye bank-delivered precut tissue, and standardization of donor preparation and host surgical steps, optimizing surgical time in the operating room. This trend should lead to better visual outcomes, faster recovery times, and eventually to a higher surgical volume per year.

Validation of Practical Tools to Identify Walking Cadence to Reach Moderate Intensity.

It is recommended that adults get at minimum 150 minutes of moderate-to-vigorous physical activity in bouts of 10 minutes or greater every week. Walking cadence (steps per minute) is one easy way to estimate intensity required, however tools that claim to quantify walking intensity via walking cadence have not been validated in adults. We aimed to validate: 1- the accuracy of walking cadence measurement by the Piezo RxD pedometer, Polar Stride Sensor Bluetooth Smart foot pod, and Garmin Ant+ foot pod at different speeds and slopes and 2- the ability of the Piezo RxD to identify bouts of walking at moderate intensity using walking cadence. Inclusion criteria included being aged 19+ and the ability to reach moderate intensity when walking without incline as determined by a treadmill cardiorespiratory fitness test to determine 40% of VO2 reserve. Walking cadence measured from the three tools was compared to a manual count of walking cadence during a series of walking stages at several speeds (2.5-5.5 km/h) and inclines (0-15%). The ability of the Piezo RxD to quantify a 10-minute bout was determined by walking for 12 minutes at 40% of VO2 reserve measured by indirect calorimetry. All correlations between manual walking cadence counts and all devices were significant regardless of speed (r ranging from 0.469 to 0.999; p ≤ 0.05) and slope (r ranging from 0.887 to 0.996; p ≤ 0.05). The Piezo RxD was able to correctly measure a 10-minute bout of walking at moderate intensity for 50 of 51 participants. We found that all walking cadence devices provided accurate measurements of walking cadence. The Piezo RxD is an effective tool to quantify bouts of walking done at a minimum of moderate intensity.

Strontium isotope (87Sr/86Sr) data from archaeological sites in Utah, USA.

The information presented here includes the results of strontium isotope analysis on 75 baseline samples from nine Fremont sites in Utah. The baseline samples are of lagomorphs and rodents with limited foraging ranges. The baseline ranges for each site were calculated with two standard deviations. Also included are the raw strontium isotopic data for 30 large game samples from Wolf Village, a Fremont site in Utah. Additional data include a map showing the location of the sites in this study, box plots portraying the local ranges of nine Fremont sites in Utah, and an individual value plot comparing the Wolf Village large game samples to the strontium baseline for the site. These data compliment the discussions and interpretations found in "Identifying Strontium Baselines and Large Game Animal Trade at Fremont Sites through Strontium Isotope (87Sr/86Sr) Analysis" [1].

Discovery of Small-Molecule Antibiotics against a Unique tRNA-Mediated Regulation of Transcription in Gram-Positive Bacteria.

The emergence of multidrug-resistant bacteria necessitates the identification of unique targets of intervention and compounds that inhibit their function. Gram-positive bacteria use a well-conserved tRNA-responsive transcriptional regulatory element in mRNAs, known as the T-box, to regulate the transcription of multiple operons that control amino acid metabolism. T-box regulatory elements are found only in the 5'-untranslated region (UTR) of mRNAs of Gram-positive bacteria, not Gram-negative bacteria or the human host. Using the structure of the 5'UTR sequence of the Bacillus subtilis tyrosyl-tRNA synthetase mRNA T-box as a model, in silico docking of 305 000 small compounds initially yielded 700 as potential binders that could inhibit the binding of the tRNA ligand. A single family of compounds inhibited the growth of Gram-positive bacteria, but not Gram-negative bacteria, including drug-resistant clinical isolates at minimum inhibitory concentrations (MIC 16-64 µg mL-1 ). Resistance developed at an extremely low mutational frequency (1.21×10-10 ). At 4 µg mL-1 , the parent compound PKZ18 significantly inhibited in vivo transcription of glycyl-tRNA synthetase mRNA. PKZ18 also inhibited in vivo translation of the S. aureus threonyl-tRNA synthetase protein. PKZ18 bound to the Specifier Loop in vitro (Kd ≈24 µm). Its core chemistry necessary for antibacterial activity has been identified. These findings support the T-box regulatory mechanism as a new target for antibiotic discovery that may impede the emergence of resistance.

Outbreak of invasive group A streptococcus: investigations using agar settle plates detect perineal shedding from a healthcare worker.

BACKGROUND: Outbreaks of group A streptococcus (GAS) infections may occur in healthcare settings. Transmission to patients is sometimes linked to colonized healthcare workers (HCWs) and/or a contaminated environment. AIM: To describe the investigation and control of an outbreak of healthcare-associated GAS on an elderly care medical ward, over six months. METHODS: Four patients developed septicaemia due to GAS infection without a clinically obvious site of infection. The outbreak team undertook an investigation involving a retrospective review of GAS cases, prospective case finding, HCW screening and environmental sampling using both swabs and settle plates. Immediate control measures included source isolation and additional cleaning of the ward environment with a chlorine disinfectant and hydrogen peroxide. FINDINGS: Prospective patient screening identified one additional patient with throat GAS carriage. Settle plate positivity for GAS was strongly associated with the presence of one individual HCW on the ward, who was subsequently found to have GAS perineal carriage. Contamination of a fabric-upholstered chair in an office adjacent to the ward, used by the HCW, was also detected. In total, three asymptomatic HCWs had throat GAS carriage and one HCW had both perineal and throat carriage. All isolates were typed as emm 28. CONCLUSION: This is the first outbreak report demonstrating the use of settle plates in a GAS outbreak investigation on a medical ward, to identify the likely source of the outbreak. Based on this report we recommend that both throat and perineal sites should be sampled if HCW screening is undertaken during an outbreak of GAS. Fabric, soft furnishings should be excluded from clinical areas as well as any adjacent offices because pathogenic bacteria such as GAS may contaminate this environment.

Current and Emerging Uses of Statins in Clinical Therapeutics: A Review.

Statins, a class of cholesterol-lowering medications that inhibit 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, are commonly administered to treat atherosclerotic cardiovascular disease. Statin use may expand considerably given its potential for treating an array of cholesterol-independent diseases. However, the lack of conclusive evidence supporting these emerging therapeutic uses of statins brings to the fore a number of unanswered questions including uncertainties regarding patient-to-patient variability in response to statins, the most appropriate statin to be used for the desired effect, and the efficacy of statins in treating cholesterol-independent diseases. In this review, the adverse effects, costs, and drug-drug and drug-food interactions associated with statin use are presented. Furthermore, we discuss the pleiotropic effects associated with statins with regard to the onset and progression of autoimmune and inflammatory diseases, cancer, neurodegenerative disorders, strokes, bacterial infections, and human immunodeficiency virus. Understanding these issues will improve the prognosis of patients who are administered statins and potentially expand our ability to treat a wide variety of diseases.

D-dimer levels and recurrence in patients with unprovoked VTE and a negative qualitative D-dimer test after treatment.

BACKGROUND: The rate of recurrent venous thromboembolism (VTE) in patients with a first unprovoked VTE who had a negative qualitative D-dimer test one month after stopping anticoagulant therapy was higher than expected in the D-dimer Optimal Duration Study (DODS). OBJECTIVES: To determine whether quantitative D-dimer levels using a low threshold, age- and sex-specific thresholds, or repeated measurements, would improve identification of patients at low risk of recurrent VTE. MATERIALS AND METHODS: D-dimer levels were quantified in banked samples from 307 patients in DODS who had a negative qualitative D-dimer test while on, and 1month after stopping, anticoagulant therapy and the rates of recurrent VTE were determined in patients with D-dimer levels below various predefined thresholds. RESULTS: The rate (per patient year) of recurrent VTE was: 5.9% with D-dimer levels<250µg/l at one month; 5.2% with D-dimer levels between 250 and 499µg/l at one month; 5.0% with D-dimer levels less than predefined age- and sex-specific thresholds at one month; and 6.3% when D-dimer levels were <500µg/l at both one and 7months after stopping anticoagulant therapy. These rates are similar to the overall event rate of 6.3% in patients who stopped treatment. CONCLUSIONS: Among unprovoked VTE patients who had a negative qualitative D-dimer test during and after anticoagulant therapy, low D-dimer thresholds, age and sex-adjusted thresholds or repeated measurements, did not identify subgroups with a very low rate of recurrence.

Use of an artificial pancreas among adolescents for a missed snack bolus and an underestimated meal bolus.

OBJECTIVE: The objective of this study was to evaluate the safety and performance of the artificial pancreas (AP) in adolescents with type 1 diabetes (T1D) following insulin omission for food. RESEARCH DESIGN AND METHODS: In a randomized, cross-over trial, adolescents with T1D aged 13-18 yr were enrolled in a randomized, cross-over trial. On separate days, received either usual care (UC) through their home insulin pump or used an AP system (Diabetes Assistant platform, continuous glucose monitor, and insulin pump). Approximately 1 h after admission, participants in both groups received an unannounced snack of 30 g carbohydrate, and 4 h later they received an 80 g lunch, for which both groups only received 75% of the calculated insulin dose to cover carbohydrates. On the UC day (but not the AP day), they received their full high blood glucose (BG) correction factor at lunch. Each admission lasted approximately 8 h. RESULTS: A total of 16 participants completed the trial. On the AP day (compared to UC), mean BG was lower (197 ± 10 vs. 235 ± 14 mg/dL) and time in range 70-180 mg/dL was higher (43% ± 7 vs. 19% ± 7) (both p < 0.05) overall; these results held in the time following the snack and meal (also p < 0.05). During the trial, there were no differences between groups in the rate of hypoglycemia <70 mg/dL. CONCLUSIONS: The AP provided improvements in short-term glycemic control without increases in hypoglycemia following missed insulin for food in adolescents. Thus, the AP partly compensates for missed insulin boluses for food, a common occurrence in adolescent diabetes care. Further testing is needed in longer-term settings.

Rapid quantitative D-dimer to exclude pulmonary embolism: a prospective cohort management study.

UNLABELLED: ESSENTIALS: It is not known if D-dimer testing alone can safely exclude pulmonary embolism (PE). We studied the safety of using a quantitative latex agglutination D-dimer to exclude PE in 808 patients. 52% of patients with suspected PE had a negative D-dimer test and were followed for 3 months. The negative predictive value of D-dimer testing alone was 99.8%, suggesting it may safely exclude PE. BACKGROUND: Strategies are needed to exclude pulmonary embolism (PE) efficiently without the need for imaging tests. Although validated rules for clinical probability assessment can be combined with D-dimer testing to safely exclude PE, the rules can be complicated or partially subjective, which limits their use. OBJECTIVES: To determine if PE can be safely excluded in patients with a negative D-dimer without incorporating clinical probability assessment. PATIENTS/METHODS: We enrolled consecutive outpatients and inpatients with suspected PE from four tertiary care hospitals. All patients underwent D-dimer testing using the MDA D-dimer test, a quantitative latex agglutination assay. PE was excluded in patients with a D-dimer less than 750 µg FEU L(-1) without further testing. PATIENTS: with D-dimer levels of 750 µg FEU L(-1) or higher underwent standardized imaging tests for PE. All patients in whom PE was excluded had anticoagulant therapy withheld and were followed for 3 months for venous thromboembolism (VTE). Suspected events during follow-up were adjudicated centrally. RESULTS: Eight hundred and eight patients were enrolled, of whom 99 (12%) were diagnosed with VTE at presentation. Four hundred and twenty (52%) patients had a negative D-dimer level at presentation and were not treated with anticoagulants; of these, one had VTE during follow-up. The negative predictive value of D-dimer testing for PE was 99.8% (95% confidence interval, 98.7-99.9%). CONCLUSIONS: A negative latex agglutination D-dimer assay is seen in about one-half of patients with suspected PE and reliably excludes PE as a stand-alone test.

Effect of standardized perioperative dabigatran interruption on the residual anticoagulation effect at the time of surgery or procedure.

UNLABELLED: ESSENTIALS: Anticoagulants need to be stopped preprocedure so there is little or no remaining anticoagulant effect. We assessed the residual anticoagulant effect with standardized interruption for patients on dabigatran. With this protocol, 80-86% of patients had no residual anticoagulant effect at the time of a procedure. A standardized perioperative dabigatran protocol appears to be safe, but requires further study. BACKGROUND: In patients taking dabigatran who require treatment interruption for a surgery/procedure, a sufficient interruption interval is needed so that there is little or no residual anticoagulant effect at the time of the surgery/procedure. METHODS: A prospective cohort study of patients receiving dabigatran (110 mg or 150 mg twice daily) who required an elective surgery/procedure and received a standardized dabigatran interruption protocol based on surgery/procedure bleeding risk and renal function was performed. Before the surgery/procedure, a blood sample was taken for measurement of the prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and dilute thrombin time (dTT). We determined the proportion of all patients and those having a high bleeding risk surgery/procedure with normal coagulation test results at the time of the surgery/procedure. The APTT and dTT were considered to be most likely to reflect a dabigatran anticoagulant effect. Patients were followed up for 30 days postprocedure to assess for bleeding and thromboembolism. RESULTS: One hundred and eighty-one patients were studied: 118 with low bleeding risk, and 63 with high bleeding risk. For all patients, the proportions with normal PT, APTT, TT dTT levels were 92.8%, 79.6%, 33.1%, and 80.7%, respectively. In patients with high bleeding risk, the proportions with normal PT, APTT, TT dTT levels were 93.7%, 85.7%, 57.1%, and 87.3%, respectively. During follow-up, there was one (0.6%) major bleed, there were nine (5.0%) minor bleeds, and there was one (0.6%) transient ischemic attack. CONCLUSIONS: In patients receiving dabigatran who require an elective surgery/procedure, a standardized interruption protocol yielded 80-86% of patients with no residual anticoagulant effect at the time of surgery/procedure, and with a low incidence of bleeding.