Validation of a fibrinogen γ' enzyme-linked immunosorbent assay using a new monoclonal antibody: effects of bariatric surgery.

Background: Fibrinogen γ' is a naturally occurring 20-amino-acid splice variant of the fibrinogen γ chain. Animal studies link variations in fibrinogen to obesity, but it is unknown how fibrinogen γ' is associated with obesity in humans. Objectives: To develop and validate an enzyme-linked immunosorbent assay (ELISA) for fibrinogen γ' quantification in human plasma and analyze fibrinogen γ' before and after bariatric surgery. Methods: We generated C-terminal fibrinogen γ' specific mouse monoclonal antibodies and developed a γ' ELISA. Validation included measures of accuracy, sensitivity, and precision. Fibrinogen γ' and total fibrinogen were measured in 60 individuals before and 6 months after bariatric surgery and in 19 normal-weight controls and 120 blood donors. Results: Highly specific fibrinogen γ' monoclonal antibodies were produced and successfully used in the ELISA. Recovery was 88%, and limits of detection and quantification were 0.003 mg/mL and 0.014 mg/mL, respectively. Coefficients of variation were 3% for repeatability and 7% for within-laboratory variation. The fibrinogen γ' reference interval was 0.25 to 0.80 mg/mL. Fibrinogen γ' concentrations were reduced after bariatric surgery and were higher in individuals with obesity than in those with normal weight. The fibrinogen γ'/total fibrinogen ratio was unchanged after surgery but was higher than the ratio in normal-weight individuals. Conclusion: We developed a precise and sensitive ELISA for fibrinogen γ'. Levels of fibrinogen γ', but not the fibrinogen γ'/fibrinogen ratio, were reduced 6 months after bariatric surgery. Absolute and relative levels of fibrinogen γ' were increased in individuals with obesity compared to normal-weight individuals.

Myocardial injury after non-cardiac surgery and per operative fibrin metabolism in patients undergoing hip-fracture surgery: an observational study.

Myocardial injury after non-cardiac surgery (MINS) is associated with a 2-3-fold increased risk of subsequent major cardiovascular events and postoperative mortality. The pathological mechanism behind MINS is not fully uncovered. We hypothesized that patients with MINS following hip fracture surgery would have an altered haemostatic balance pre- and postoperative compared with patients without MINS. This was investigated in a prospective single-centre observational study including patients consecutively. The outcomes were changes in thrombin generation, fibrinogen/fibrin turnover, tissue plasminogen activator, plasminogen activator inhibitor-1 and fibrin structure measurements in patients developing MINS and patients who did not. Outcomes were measured preoperatively and two hours postoperatively. Seventy-two patients were included whereof 26 (36%) patients developed MINS. D-dimer delta values were significantly higher in patients developing MINS than in patients who did not (p = 0.01). After adjusting for age, sex, smoking, alcohol abuse, atrial fibrillation, anticoagulant medication preoperative CRP, preoperative creatinine and duration of surgery, the association remained significant (p = 0.04). There were no significant changes in thrombin generation, in markers of fibrinogen/fibrin turnover besides D-dimer, or in fibrin structure measurements pre- and postoperatively between patients with and without MINS. As such, a relationship between the coagulative and fibrinolytic activity and MINS cannot be ruled out in patients with MINS after hip fracture surgery. Registration: The study was an observational sub-study to a multicentre randomised clinical trial registered at ClinicalTrials.gov (NCT02344797).

Small-Area Analysis of Treatment and Clinical Outcomes in Patients with Venous Thromboembolism in Denmark: A Nationwide Cohort Study.

OBJECTIVES: To investigate geographical variation in initiation and extended treatment with anticoagulants and clinical outcomes among patients hospitalized with first-time venous thromboembolism (VTE) in Denmark between 2007 and 2018. METHODS: Using nationwide health care registries, we identified all patients with a first-time VTE hospital diagnosis supported by imaging data from 2007 to 2018. Patients were grouped according to residential region (5) and municipality (98) at the time of VTE diagnosis. Cumulative incidence of initiation of and extended (beyond 365 days) anticoagulation treatment as well as clinical outcomes, including recurrent VTE, major bleeding, and all-cause death, were assessed. Sex- and age-adjusted relative risks (RRs) of the outcomes were computed when comparing across individual regions and municipalities. Overall geographic variation was quantified by computing the median RR. RESULTS: We identified 66,840 patients with a first-time VTE hospitalization. A difference in initiation of anticoagulation treatment of more than 20 percentage points between regions was observed (range: 51.9-72.4%, median RR: 1.09, 95% confidence interval [CI]: 1.04-1.13). Variation was also observed for extended treatment (range: 34.2-46.9%, median RR: 1.08, 95% CI: 1.02-1.14). The cumulative incidence of recurrent VTE ranged from 3.6 to 5.3% at 1 year (median RR: 1.08, 95% CI: 1.01-1.15). The difference remained after 5 years, and variation was also observed for major bleeding (median RR: 1.09, 95% CI: 1.03-1.15), whereas it appeared smaller for all-cause mortality (median RR: 1.03, 95% CI: 1.01-1.05). CONCLUSION: Substantial geographical variation in anticoagulation treatment and clinical outcomes occurs in Denmark. These findings indicate a need for initiatives to ensure uniform high-quality care for all VTE patients.

Platelet aggregation in Klinefelter syndrome is not aggravated by testosterone replacement therapy: A longitudinal follow-up study.

BACKGROUND: Men with Klinefelter syndrome (KS) are routinely offered testosterone replacement therapy (TRT) suggested to potentially promote platelet aggregation and increase cardiovascular risk. OBJECTIVE: We investigated platelet aggregation in men with KS before and during TRT. MATERIALS AND METHODS: Forty-one adult men with KS participated, of which 20 had no history of TRT at baseline, with 15 completing follow-up after 18 months TRT. Further, we included 21 adult men with KS on long-term TRT (>10 years) and a male reference population. We assessed platelet impedance aggregometry using adenosine diphosphate (6.5 µM), thrombin-receptor-activating-peptide-6 (TRAP 32 µM), and arachidonic acid (ASPI 0.5 mM) as agonists in KS compared to a male reference population and stratified by route of TRT administration. RESULTS: Platelet aggregation among men with KS at baseline or during TRT was not increased compared with the male reference population. For all three agonist, no change was seen in platelet aggregation in KS at follow-up compared with baseline (p ≥ 0.2). Platelet aggregation was not associated with total testosterone and furthermore, platelet count was not affected by treatment with testosterone. Men with KS treated with testosterone gel showed slightly increased TRAP- and ASPI-induced platelet aggregation compared with those treated with testosterone injection (p = 0.02 and p = 0.04, respectively). DISCUSSION AND CONCLUSIONS: We observed normal platelet aggregation in men with KS before TRT and following both short and long term treatment. Our findings do not support an independent role of platelets in driving the cardiovascular risk in KS.

Gastrointestinal bleeding and the risk of colorectal cancer in anticoagulated patients with atrial fibrillation.

AIMS: Gastrointestinal bleeding (GI-bleeding) is frequent in patients with atrial fibrillation (AF) treated with oral anticoagulation (OAC) therapy. We sought to investigate to what extent lower GI-bleeding represents the unmasking of an occult colorectal cancer. METHODS AND RESULTS: A total of 125 418 Danish AF patients initiating OAC therapy were identified using Danish administrative registers. Non-parametric estimation and semi-parametric absolute risk regression were used to estimate the absolute risks of colorectal cancer in patients with and without lower GI-bleeding. During a maximum of 3 years of follow-up, we identified 2576 patients with lower GI-bleeding of whom 140 patients were subsequently diagnosed with colorectal cancer within the first year of lower GI-bleeding. In all age groups, we observed high risks of colorectal cancer after lower GI-bleeding. The absolute 1-year risk ranged from 3.7% [95% confidence interval (CI) 2.2-6.2] to 8.1% (95% CI 6.1-10.6) in the age groups ≤65 and 76-80 years of age, respectively. When comparing patients with and without lower GI-bleeding, we found increased risk ratios of colorectal cancer across all age groups with a risk ratio of 24.2 (95% CI 14.5-40.4) and 12.3 (95% CI 7.9-19.0) for the youngest and oldest age group of ≤65 and >85 years, respectively. CONCLUSION: In anticoagulated AF patients, lower GI-bleeding conferred high absolute risks of incident colorectal cancer. Lower GI-bleeding should not be dismissed as a benign consequence of OAC therapy but always examined for a potential underlying malignant cause.

Effect of remote ischemic preconditioning on fibrin formation and metabolism in patients undergoing hip fracture surgery: a randomized clinical trial.

Remote ischemic preconditioning (RIPC) prior to surgery has recently been shown to reduce the risk of myocardial injury and myocardial infarction after hip fracture surgery. This study investigated whether RIPC initiated antithrombotic mechanisms in patients undergoing hip fracture surgery. This trial was a predefined sub-study of a multicentre randomized clinical trial. Adult patients with cardiovascular risk factors undergoing hip fracture surgery between September 2015 and September 2017 were randomized 1 : 1 to RIPC or control. RIPC was initiated before surgery with a tourniquet applied to the upper arm and it consisted of four cycles of 5 min of forearm ischemia followed by five minutes of reperfusion. The outcomes such as surgery-induced changes in thrombin generation, fibrinogen/fibrin turnover, tissue plasminogen activator, plasminogen activator inhibitor-1 and fibrin structure measurements were determined preoperatively (prior to RIPC) and 2 h postoperatively. One hundred and thirty-seven patients were randomized to RIPC (n = 65) or control (n = 72). There were no significant changes in thrombin generation, fibrinogen/fibrin turnover or fibrin structure measurements determined pre and postoperatively between patients in the RIPC and control groups. Subgroup analyses on patients not on anticoagulant therapy (n = 103), patients receiving warfarin (n = 17) and patients receiving direct oral anticoagulant therapy (n = 18) showed no significant changes between the RIPC-patients and controls. RIPC did not affect changes in thrombin generation, fibrin turnover or fibrin structure in adult patients undergoing hip fracture surgery suggesting that the cardiovascular effect of RIPC in hip fracture surgery is not related to alterations in fibrinogen/fibrin metabolism.

Effectiveness and safety of oral anticoagulation treatment beyond 1 year after venous thromboembolism in patients at intermediate recurrence risk.

Effectiveness and safety of long-term anticoagulation treatment are uncertain in venous thromboembolism (VTE) patients at intermediate risk of recurrence. We examined the association between treatment beyond 1 year and outcomes in a Danish nationwide register-based study. VTE patients at intermediate risk of recurrence, that is, non-cancer patients with a first-time unprovoked VTE, who started oral anticoagulation treatment within 30 days and were alive 365 days after the index VTE were included and followed between 2007 and 2015. Exposure was extended (>365 days) or intermediate (91-365 days) treatment. Analyses were done using Cox regression on a propensity score weighted population. We included 18 609 patients with 7232 (38.9%) receiving extended treatment. Mean duration of follow-up was 2.6 years. Compared with intermediate treatment, treatment beyond 365 days was associated with a lower weighted risk of recurrent VTE (hazard ratio [HR] 0.56, 95% confidence interval [CI] 0.49-0.65) and all-cause mortality (HR 0.81, 95% CI 0.72-0.90) and an increased risk of major bleeding (HR 1.87, 95% CI 1.58-2.22). In conclusion, extended anticoagulation treatment (predominantly warfarin) beyond 1 year was in real-life settings associated with a lower risk of recurrent VTE and all-cause mortality among VTE patients with an intermediate risk of recurrence. However, an increased bleeding risk should be considered.

Reductions in plasmin inhibitor and fibrinogen predict the improved fibrin clot lysis 6 months after obesity surgery.

Prothrombotic and metabolic variables are decreased after obesity surgery, and fibrin clot lysis is increased. It is unknown how fibrinolytic variables are affected, and whether fibrinolytic and metabolic changes predict the enhanced clot lysis. Study aims were to determine fibrinolytic biomarkers before and 6 months after Roux-en-Y gastric bypass (RYGB) and to identify predictors of the RYGB-induced increase in clot lysis. Women (n = 42) and men (n = 18) with obesity underwent RYGB, and factor XIII (FXIII), thrombin activatable fibrinolysis inhibitor (TAFI), plasminogen and plasmin inhibitor (PI) were measured before and 6 months after surgery. Regression analyses identified determinants of the RYGB-induced increase in clot lysis among changes in fibrinogen and in fibrinolytic and metabolic variables. Results showed that after RYGB, FXIII, TAFI, plasminogen and PI were reduced (P < .0005). Reductions in PI (ß = -0.59) and fibrinogen (ß = -0.35), together with age (ß = -0.22) and male sex (ß = 0.22), predicted the enhanced clot lysis with the model explaining 56% (P < .0005). Predictors of the reduction in PI were reductions in cholesterol (ß = 0.37) and glucose (ß = 0.29), together with male sex (ß = -0.28), whereas reductions in fibrinogen were predicted by lowering of interleukin-6 (IL-6) (ß = 0.32). In conclusion, fibrinolytic variables were reduced 6 months after RYGB. Targeting PI and fibrinogen, by reducing metabolic variables such as glucose, cholesterol and IL-6, has a profibrinolytic effect in obesity.

The effect of remote ischaemic preconditioning on myocardial injury in emergency hip fracture surgery (PIXIE trial): phase II randomised clinical trial.

OBJECTIVE: To investigate whether remote ischaemic preconditioning (RIPC) prevents myocardial injury in patients undergoing hip fracture surgery. DESIGN: Phase II, multicentre, randomised, observer blinded, clinical trial. SETTING: Three Danish university hospitals, 2015-17. PARTICIPANTS: 648 patients with cardiovascular risk factors undergoing hip fracture surgery. 286 patients were assigned to RIPC and 287 were assigned to standard practice (control group). INTERVENTION: The RIPC procedure was initiated before surgery with a tourniquet applied to the upper arm and consisted of four cycles of forearm ischaemia for five minutes followed by reperfusion for five minutes. MAIN OUTCOME MEASURES: The original primary outcome was myocardial injury within four days of surgery, defined as a peak plasma cardiac troponin I concentration of 45 ng/L or more caused by ischaemia. The revised primary outcome was myocardial injury within four days of surgery, defined as a peak plasma cardiac troponin I concentration of 45 ng/L or more or high sensitive troponin I greater than 24 ng/L (the primary outcome was changed owing to availability of testing). Secondary outcomes were peak plasma troponin I and total troponin I release during the first four days after surgery (cardiac and high sensitive troponin I), perioperative myocardial infarction, major adverse cardiovascular events, and all cause mortality within 30 days of surgery, length of postoperative stay, and length of stay in the intensive care unit. Several planned secondary outcomes will be reported elsewhere. RESULTS: 573 of the 648 randomised patients were included in the intention-to-treat analysis (mean age 79 (SD 10) years; 399 (70%) women). The primary outcome occurred in 25 of 168 (15%) patients in the RIPC group and 45 of 158 (28%) in the control group (odds ratio 0.44, 95% confidence interval 0.25 to 0.76; P=0.003). The revised primary outcome occurred in 57 of 286 patients (20%) in the RIPC group and 90 of 287 (31%) in the control group (0.55, 0.37 to 0.80; P=0.002). Myocardial infarction occurred in 10 patients (3%) in the RIPC group and 21 patients (7%) in the control group (0.46, 0.21 to 0.99; P=0.04). Statistical power was insufficient to draw firm conclusions on differences between groups for the other clinical secondary outcomes (major adverse cardiovascular events, 30 day all cause mortality, length of postoperative stay, and length of stay in the intensive care unit). CONCLUSIONS: RIPC reduced the risk of myocardial injury and infarction after emergency hip fracture surgery. It cannot be concluded that RIPC overall prevents major adverse cardiovascular events after surgery. The findings support larger scale clinical trials to assess longer term clinical outcomes and mortality. TRIAL REGISTRATION: ClinicalTrials.gov NCT02344797.

Nintedanib in Idiopathic Pulmonary Fibrosis: Practical Management Recommendations for Potential Adverse Events.

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease with a dismal survival rate of only 3 years and no curative pharmacological therapy. The recent approval of 2 anti-fibrotic drugs (nintedanib and pirfenidone) that slow disease progression has provided some hope for patients. However, effectively managing anti-fibrotic treatment can be a challenge due to tolerability issues, the presence of pulmonary and extra-pulmonary comorbidities, and the need for concomitant medications in many patients. In general, making clear evidence-based decisions can be difficult for physicians because patients with comorbidities are often excluded from clinical trials. Since currently anti-fibrotic drugs are the only effective therapeutics capable of slowing disease progression, it is imperative that all treatment options are thoroughly evaluated and exhausted in each individual, irrespective of complicating factors, to permit the best outcome for the patient. In this review, we present data from clinical trials, post hoc analyses, post-marketing surveillance, and real-world studies that are relevant to the management of nintedanib treatment. In addition, we also provide practical recommendations developed by a multidisciplinary panel of experts for the management of nintedanib treatment in patients with IPF associated complications and those experiencing gastrointestinal side effects.

Protocol Outlines for Parts 1 and 2 of the Prospective Endoscopy III Study for the Early Detection of Colorectal Cancer: Validation of a Concept Based on Blood Biomarkers.

BACKGROUND: Programs for population screening of colorectal cancer (CRC) have been implemented in several countries with fecal immunochemical testing (FIT) as the preferred platform. However, the major obstacle for a feces-based testing method is the limited compliance that reduces the clinical sensitivity for detection of participants with non-symptomatic CRC. Therefore, research approaches have been initiated to develop screening concepts based on biomarkers in blood. Preliminary results show that protein, genetic, epigenetic, and metabolomic components may be valuable in blood-based screening concepts, particularly when combinations of the various components appear to lead to significant improvements. OBJECTIVES: The protocol described in this paper focuses on the validation of concepts based on biomarkers in blood in a major population screened by FIT. METHODS: In Part 1, participants will be identified and included through the Danish CRC Screening Program comprising initial FIT and subsequent colonoscopy to those with a positive result. Blood samples will be collected from 8000 FIT-positive participants, who are offered subsequent colonoscopy. Findings and interventions at colonoscopy together with personal data including co-morbidity will be recorded. Blood samples and data will also be collected from 6000 arbitrarily chosen participants with negative FIT. In Part 2, blood samples and data will be collected from 30,000 FIT-negative participants three times within 4 years. The blood samples will be analyzed using various in-house and commercially available manual and automated analysis platforms. RESULTS: We anticipate Part 1 to terminate late August 2016 and Part 2 to terminate late September 2022. The results from Parts 1 and 2 will be presented within 12 to 18 months from termination. CONCLUSIONS: The purpose of this study is to improve the efficacy of identifying participants with neoplastic bowel lesions, to identify false negative participants, to identify participants at risk of interval neoplastic lesions, to improve the compliance in screening sessions, and to establish guidelines for out-patient follow-up of at-risk participants based on combinations of blood-based biomarkers.

Venous thromboembolism and subsequent risk of cancer in patients with liver disease: a population-based cohort study.

OBJECTIVE: Venous thromboembolism (VTE) may be a marker of occult cancer in the general population. While liver disease is known to increase the risk of VTE and cancer, it is unclear whether VTE in patients with liver disease is also a marker of occult cancer. DESIGN: A population-based cohort study. SETTING: Denmark. PARTICIPANTS: We used population-based health registries to identify all patients with liver disease in Denmark with a first-time diagnosis of VTE (including superficial or deep venous thrombosis and pulmonary embolism) during 1980-2010. Patients with non-cirrhotic liver disease and patients with liver cirrhosis were followed as two separate cohorts from the date of their VTE. MEASURES: For each cohort, we computed the absolute and relative risk (standardised incidence ratio; SIR) of cancer after VTE. RESULTS: During the study period, 1867 patients with non-cirrhotic liver disease and 888 with liver cirrhosis were diagnosed with incident VTE. In the first year following VTE, the absolute risk of cancer was 2.7% among patients with non-cirrhotic liver disease and 4.3% among those with liver cirrhosis. The SIR for the first 90 days of follow-up was 9.96 (95% CI 6.85 to 13.99) among patients with non-cirrhotic liver disease and 13.11 (95% CI 8.31 to 19.67) among patients with liver cirrhosis. After 1 year of follow-up, SIRs declined, but remained elevated in patients with non-cirrhotic liver disease (SIR=1.50, 95% CI 1.23 to 1.81) and patients with liver cirrhosis (SIR=1.95, 95% CI 1.45 to 2.57). CONCLUSIONS: VTE may be a marker of occult cancer in patients with liver disease.

Clinical and preclinical validation of the serum free light chain assay: identification of the critical difference for optimized clinical use.

OBJECTIVES: The use of the assay for the measurements of free light chains in serum (sFLCs) is increasing. However, there are technical limitations that potentially affect the use in serial measurements. We need further knowledge on the standards of analytical precision, the utility of conventional population-based reference values and the critical difference (CD) between serial results required for significance. To answer these questions, the biological variation must be known. METHODS: We determined the biological variation in healthy individuals and patients with plasma cell dyscrasia (PCD). We assessed the imprecision of the analysis in use from FreeLite™. We determined the reference interval (RI) in 170 healthy individuals. RESULTS: The biological variation is identical for healthy individuals and patients with PCD. The imprecision of the sFLC analysis cannot fulfil the desirable performance standards for a laboratory test, but are within the manufacturer's ±20% variation for quality control samples. RI showed a significant increase for κ FLC and κ/λ ratio with age, but not for λ. Critical difference was calculated to be 24% and 23% for κ and λ, respectively. CONCLUSIONS: We suggest the use of an age-dependent RI. When monitoring patients with PCD, their own former results are the best reference, and knowledge on CD is a valuable tool, which we describe for the first time. Also, it challenges the recently proposed International Myeloma Working Group 'paraprotein relapse criteria', recommending an increase of more than 25% in the involved FLC to indicate the need for initiation of retreatment. We recommend revision of this criterion.

[Determination of light chains in serum]. / Bestemmelse af lette kaeder i serum.

Free light chains of the immunoglobulin are identical to the Bence Jones protein. In 2001, a commercially available assay for the measurement of free light chains in serum (sFLC) became available (FreeLite Free Kappa & Free Lambda assay). Evidence from the use of the sFLC analysis is rapidly building, and the analysis is a potentially powerful supplement to the diagnostic tools already used in the diagnosis and monitoring of patients with monoclonal plasma cell disorders. However, there are several unsolved aspects for the use of this analysis which must be considered before sFLC can be used optimally in a daily clinical setting.