A clinical proteomics study of exhaled breath condensate and biomarkers for pulmonary embolism.

Pulmonary embolism (PE) can be a diagnostic challenge. Current diagnostic markers for PE are unspecific and new diagnostic tools are needed. The air we exhale is a possible new source for biomarkers which can be tapped into by analysing the exhaled breath condensate (EBC). We analysed the EBC from patients with PE and controls to investigate if the EBC is a useful source for new diagnostic biomarkers of PE. We collected and analysed EBC samples from patients with suspected PE and controls matched on age and sex. Patients in whom PE was ruled out after diagnostic work-up were included in the control group to increase the sensitivity and generalizability of the identified markers. EBC samples were collected using an RTube™. The protein composition of the EBCs were analysed using data dependent label-free quantitative nano liquid chromatography-tandem mass spectrometry. EBC samples from 28 patients with confirmed PE, and 49 controls were analysed. A total of 928 EBC proteins were identified in the 77 EBC samples. As expected, a low protein concentration was determined which resulted in many proteins with unmeasurable levels in several samples. The levels of HSPA5, PEBP1 and SFTPA2 were higher and levels of POF1B, EPPK1, PSMA4, ALDOA, and CFL1 were lower in PE compared with controls. In conclusion, the human EBC contained a variety of endogenous proteins and may be a source for new diagnostic markers of PE and other diseases.

Combined oral contraceptives may activate the contact system in healthy women.

Background: The contact system (CAS) is part of the coagulation system, consisting of a group of plasma proteins stimulating inflammation, coagulation, and fibrinolysis when activated. CAS can be triggered by several activating surfaces, and CAS may play a potential role in thrombus formation. Combined oral contraceptives (COCs) are known to increase the risk of venous thromboembolism, and COCs induce various prothrombotic changes in the coagulation system, whereas the effect of COC on CAS has not been thoroughly investigated. Objectives: To investigate CAS in COC users compared with nonusers. Methods: Blood samples from 62 study subjects, 30 COC users, and 32 nonusers, were analyzed. Coagulation factor XII (FXII), prekallikrein (PK), H-Kininogen (HK), cleaved HK (cHK), C1-esterase inhibitor (C1-inh), and the endogenous kallikrein potential (EKP) were measured. Results: COC users had significantly higher FXII (median, 38.4 vs 28.9 mg/L) and lower C1-inh levels (0.20 vs 0.23 g/L) than nonusers. The levels of PK and HK were not significantly different. Measurement of EKP indicated an increased capacity of CAS in COC users (1860 vs 1500 nmol/L × min), and increased plasma levels of cHK (2.02 vs 1.07 µg/L) indicated an increased activity in vivo. Conclusion: This study demonstrates an increased CAS capacity in women using COC compared with nonusers and also an increased activity in vivo. The results indicate that increased contact activation may contribute to the increased thrombotic risk caused by COC.

Validation of Postsurgical Venous Thromboembolism Diagnoses of Patients Undergoing Lower Limb Orthopedic Surgery in the Danish National Patient Registry.

BACKGROUND: Healthcare databases can be a valuable source of epidemiological research regarding postoperative venous thromboembolism (VTE), ie, deep vein thrombosis (DVT) and pulmonary embolism (PE), following orthopedic procedures, but only if the diagnoses are valid. We examined the validity of VTE diagnosis codes in the Danish National Patient Registry (DNPR) by calculating their positive predictive value (PPV) and negative predictive value (NPV) versus actual medical records. METHODS: We identified patients who had undergone lower limb surgery during the period 2009-2019 at a hospital in the North Denmark Region. Of these, 420 patients had at least one VTE diagnosis registered in the DNPR within 180 days after lower limb surgery. Each patient with a VTE diagnosis was matched with two patients on age and sex, as well as type, location and period of surgery. The entire medical record and diagnostic imaging were reviewed to confirm VTE diagnosis. RESULTS: The overall PPVs was 85.2% (95% CI: 81.5-88.5%) for first time VTE diagnosis following lower limb surgery, 82.6% (95% CI: 77.5-82.8%) for DVT, and 90.3% (95% CI: 84.3-94.6%) for PE. We found improvement in PPV during the study period when stratifying for three periods of the whole period. There were no significant differences when stratifying for sex, age, or surgery site. All negative predictive values were higher than 99%. A total of 113 additional VTE diagnoses were registered among 88 VTE patients during follow-up. Only four of the suspected recurrent VTEs were confirmed to be true recurrent VTEs. CONCLUSION: The VTE diagnosis codes in the DNPR after lower limb orthopedic surgery were highly valid against the actual medical records, and we observed better PPV over recent years.

Validation of the Khorana score for predicting venous thromboembolism in 40 218 patients with cancer initiating chemotherapy.

The Khorana score is recommended for guiding primary venous thromboembolism (VTE) prophylaxis in cancer patients, but its clinical utility overall and across cancer types remains debatable. Also, some previous validation studies have ignored the competing risk of death, hereby potentially overestimating VTE risk. We identified ambulatory cancer patients initiating chemotherapy without other indications for anticoagulation using Danish health registries and estimated 6-month cumulative incidence of VTE stratified by Khorana levels. Analyses were conducted with and without considering death as a competing risk using the Kaplan-Meier method vs the cumulative incidence function. Analyses were performed overall and stratified by cancer types. Of 40 218 patients, 35.4% were categorized by Khorana as low risk (score 0), 53.6% as intermediate risk (score 1 to 2), and 10.9% as high risk (score ≥3). Considering competing risk of death, the corresponding 6-month risks of VTE were 1.5% (95% confidence interval [CI], 1.3-1.7), 2.8% (95% CI, 2.6-3.1), and 4.1% (95% CI, 3.5-4.7), respectively. Among patients recommended anticoagulation by guidelines (Khorana score ≥2), the 6-month risk was 3.6% (95% CI, 3.3-3.9). Kaplan-Meier analysis overestimated incidence up to 23% compared with competing risk analyses. Using the guideline-recommended threshold of ≥2, the Khorana score did not risk-stratify patients with hepatobiliary or pancreatic cancer, lung cancer, and gynecologic cancer. In conclusion, the Khorana score was able to stratify ambulatory cancer patients according to the risk of VTE, but not for all cancer types. Absolute risks varied by methodology but were lower than in key randomized trials. Thus, although certain limitations with outcome identification using administrative registries apply, the absolute benefit of implementing routine primary thromboprophylaxis in an unselected cancer population may be smaller than seen in randomized trials.

Putative Biomarkers for Acute Pulmonary Embolism in Exhaled Breath Condensate.

Current diagnostic markers for pulmonary embolism (PE) are unspecific. We investigated the proteome of the exhaled breath condensate (EBC) in a porcine model of acute PE in order to identify putative diagnostic markers for PE. EBC was collected at baseline and after the induction of autologous intermediate-risk PE in 14 pigs, plus four negative control pigs. The protein profiles of the EBC were analyzed using label-free quantitative nano liquid chromatography-tandem mass spectrometry. A total of 897 proteins were identified in the EBCs from the pigs. Alterations were found in the levels of 145 different proteins after PE compared with the baseline and negative controls: albumin was among the most upregulated proteins, with 14-fold higher levels 2.5 h after PE (p-value: 0.02). The levels of 49 other proteins were between 1.3- and 17.1-fold higher after PE. The levels of 95 proteins were lower after PE. Neutrophil gelatinase-associated lipocalin (fold change 0.3, p-value < 0.01) was among the most reduced proteins 2.5 h after PE. A prediction model based on penalized regression identified five proteins including albumin and neutrophil gelatinase-associated lipocalin. The model was capable of discriminating baseline samples from EBC samples collected 2.5 h after PE correctly in 22 out of 27 samples. In conclusion, the EBC from pigs with acute PE contained several putative diagnostic markers of PE.

Venous thromboembolism after lower extremity orthopedic surgery: A population-based nationwide cohort study.

BACKGROUND: Venous thromboembolism (VTE) causes morbidity and mortality in the general population. Several events occur after lower limb orthopedic surgery, but the contribution from various types of lower limb surgery is not well known. OBJECTIVE: To investigate the postoperative incidence of VTE for all types of lower extremity orthopedic surgery compared with the background population. METHODS: Individual-level linkage of Danish nationwide register data for all Danish residents with first-time orthopedic surgery of the lower limb (1996-2017) and, for each of these, four controls from the general population matched on age, sex, and history of VTE. Adjusted hazard ratios (HR) compared the postoperative risk of VTE to the matched controls. RESULTS: In total 7203 of the 1 012 823 patients with a first orthopedic procedure had a VTE within 180 days after surgery, corresponding to a postoperative cumulative incidence of 0.71% (95% confidence interval [CI], 0.70-0.73). The cumulative incidence of VTE among controls was 0.11% (95% CI, 0.11-0.12). The HR of VTE within the first 30 days after surgery below knee level was 20.5 (95% CI, 17.9-23.5) compared with matched controls. The HRs of VTE after minor distal procedures (eg, meniscectomy and arthroscopies) were 2.9 (95% CI, 1.9-4.4) to 7.1 (95% CI, 6.4-8.0). CONCLUSION: All types of lower limb orthopedic surgery including minor distal procedures were associated with higher rates of VTE compared with matched controls, in particular within the first 30 days after surgery.

Exhaled breath condensate in acute pulmonary embolism; a porcine study of effect of condensing temperature and feasibility of protein analysis by mass spectrometry.

The search for diagnostic biomarkers for pulmonary embolism (PE) has mainly been focused on blood samples. Exhaled breath condensate (EBC) is a possible source for biomarkers specific for chronic lung diseases and cancer, yet no previous studies have investigated the potential of EBC for diagnosis of PE. The protein content in the EBC is very low, and efficient condensing of the EBC is important in order to obtain high quality samples for protein analysis. We investigated if advanced proteomic techniques in a porcine model of acute intermediate-high-risk PE was feasible using two different condensing temperatures for EBC collection. Seven pigs were anaesthetized and intubated. EBC was collected one hour after intubation. Two autologous emboli were induced through the right external jugular vein. Two hours after the emboli were administered, EBC was collected again. Condensing temperature was either -21 °C or -80 °C. Nano liquid chromatography-tandem mass spectrometry (nLC-MS/MS) was used to identify and quantify proteins of the EBC. A condensing temperature of -80 °C significantly increased the EBC volume compared with -21 °C (1.78 ± 0.25 ml vs 0.71 ± 0.12 ml) while the protein concentration in the EBC was unaltered. The mean protein concentration in the EBCs was 5.85 ± 0.93µg ml-1, unaltered after PE. In total, 254 proteins were identified in the EBCs. Identified proteins included proteins of the cytoplasm, nucleus, plasma membrane and extracellular region. The protein composition did not differ according to condensing temperature. The EBC from pigs with acute intermediate-high-risk PE contained sufficient amounts of protein for analysis by nLC-MS/MS. The proteins were from relevant cellular compartments, indicating that EBC is a possible source for biomarkers for acute PE.

Epidemiology of Venous Thromboembolism After Second Cancer.

BACKGROUND: Venous thromboembolism (VTE) is a serious, yet preventable, complication in cancer. Some patients are diagnosed with a second cancer; however, little is known about the epidemiology of VTE in this population. METHODS: From Danish national healthcare registries, we studied all patients diagnosed with a first breast, prostate, lung, or colorectal cancer from 1995 to 2015. We estimated incidence rates (IRs) of VTE according to the timing of the diagnosis of a second cancer. We controlled for confounder variables in Poisson regression models. RESULTS: In total, 309,077 patients with a first breast, prostate, lung, or colorectal cancer were included in the study. A second cancer was diagnosed in 20,090 (6.5%) of these patients. In total, 11,908 VTEs were observed in the study period, 786 of these occurred after a diagnosis of second cancer. Second cancer types such as pancreas and stomach cancer were associated with fivefold higher IRs of VTE compared with second cancer types such as breast and prostate cancer. The IR of VTE was highest within the first 6 months after the second cancer was diagnosed (IR 40.5 per 1000 person-years, 95% CI 36.3-42.2) with no differences based on how long since the first cancer it was diagnosed. CONCLUSION: The epidemiology of VTE after a second cancer is similar to the epidemiology of VTE after a first cancer with higher rates within the first months after aggressive second cancer types.

Riociguat, sildenafil and inhaled nitric oxide reduces pulmonary vascular resistance and improves right ventricular function in a porcine model of acute pulmonary embolism.

BACKGROUND: Pulmonary vasodilators as add-on to current treatment strategies in acute pulmonary embolism may improve right ventricular unloading and hence improve patient outcome. We aimed to investigate whether stimulation of the nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway with riociguat, sildenafil or inhaled NO causes pulmonary vasodilation and improves right ventricular function in a porcine model of acute intermediate risk pulmonary embolism. METHODS: Two large autologous blood clots were administered to the pulmonary circulation of 28 pigs (60 kg). Animals were randomized to four increasing, clinically equivalent doses of riociguat (n=6), sildenafil (n=6), inhaled NO (n=6) or vehicle (n=6). Sham animals (n=4) did not receive pulmonary embolism or treatment. Haemodynamic responses were evaluated at baseline, after pulmonary embolism and after each dose using invasive pressure measurements, transoesophageal echocardiography, respiratory parameters and blood analysis. RESULTS: Pulmonary embolism caused a three-fold increase in pulmonary vascular resistance compared with baseline (pulmonary embolism: 352±29 vs. baseline: 107±6 dynes, p<0.0001). All treatments lowered pulmonary vascular resistance compared with vehicle (riociguat: -158±35, sildenafil: -224±35, inhaled NO: -156±35 dynes, p<0.0001). Sildenafil, but neither inhaled NO nor riociguat, caused a decrease in systemic vascular resistance (sildenafil 678±41 vs. vehicle 1081±93 dynes, p=0.02) and increased cardiac output (sildenafil 8.8±0.8 vs. vehicle: 5.9±0.2 L/min, p<0.001). Systemic blood pressure was unaltered in all treatment groups. CONCLUSION: Stimulation of the NO-sGC-cGMP pathway by riociguat, sildenafil and inhaled NO reduces pulmonary vascular resistance in a porcine model of acute pulmonary embolism without lowering systemic blood pressure.

Venous thromboembolism in chronic lymphocytic leukemia: a Danish nationwide cohort study.

Venous thromboembolism (VTE) is associated with inferior survival in cancer patients. The risk of VTE and its effect on survival in chronic lymphocytic leukemia (CLL) patients remains unclear. The present study investigated the impact of patient-related factors, CLL prognostic markers, and CLL treatment on the risk of VTE and assessed overall survival relative to VTE. All patients in the Danish National CLL Registry (2008-2015) were followed from the date of CLL diagnosis to death, VTE, emigration, or administrative censoring. Hazard ratios (HRs) were estimated using Cox models, and second primary cancers and anticoagulation treatment were included as time-varying exposures. During a median follow-up of 2.6 years, 92 VTEs occurred among 3609 CLL patients, corresponding to a total incidence rate of 8.2 VTEs per 1000 person-years (95% confidence interval [CI], 6.7-10.1). A history of VTE or second primary cancer was associated with HRs of VTE of 5.09 (95% CI, 2.82-9.17) and 3.72 (95% CI, 2.15-6.34), respectively, while ß2-microglobulin >4 mg/L, unmutated immunoglobulin HV and unfavorable cytogenetics had lower HRs. CLL patients with VTE had marginally higher mortality, which was most pronounced among patients <60 years of age (HR, 7.74; 95% CI, 2.12-28.29). Our findings suggest that markers of unfavorable CLL prognosis contribute to an increased risk of VTE; however, previous VTE or a second primary cancer is more strongly associated with the risk of VTE than any CLL-specific marker. Focusing attention on this preventable complication may improve survival in young CLL patients.

Treatment strategies, outcomes and prognostic factors in 291 patients with secondary CNS involvement by diffuse large B-cell lymphoma.

PURPOSE: Secondary CNS involvement (SCNS) is a profoundly adverse complication of diffuse large B-cell lymphoma. Evidence from older series indicated a median overall survival (OS) < 6 months; however, data from the immunochemotherapy era are limited. METHODS: Patients diagnosed with SCNS during or after first-line immunochemotherapy were identified from databases and/or regional/national registries from three continents. Clinical information was retrospectively collected from medical records. RESULTS: In total, 291 patients with SCNS were included. SCNS occurred as part of first relapse in 254 (87%) patients and 113 (39%) had concurrent systemic relapse. With a median post-SCNS follow-up of 48 months, the median post-SCNS OS was 3.9 months and 2-year OS rate was 20% (95% CI: 15-25). In multivariable analysis of 173 patients treated with curative/intensive therapy (such as high-dose methotrexate [HDMTX] or platinum-containing regimens), age ≤60 years, performance status 0-1, absence of combined leptomeningeal and parenchymal involvement, and SCNS occurring after completion of first-line therapy were associated with superior outcomes. Patients ≤60 years with performance status 0-1 and treated with HDMTX-based regimens for isolated parenchymal SCNS had a 2-year OS of 62% (95% CI: 36-80). In patients with isolated SCNS, the addition of rituximab to HDMTX-based regimens was associated with improved OS. Amongst patients with isolated SCNS in CR following intensive treatment, high-dose chemotherapy and autologous stem cell transplantation did not improve OS (P = 0.9). CONCLUSIONS: In this large international cohort of patients treated with first-line immunochemotherapy, outcomes following SCNS remain poor. However, a moderate proportion of patients with isolated SCNS who received intensive therapies achieved durable remissions.

Long-Term Incidence of Venous Thromboembolism in Cancer: The Scandinavian Thrombosis and Cancer Cohort.

The risk of venous thromboembolism (VTE) in patients who survive the first years after a cancer diagnosis after the acute effects of disease and treatment in comparison to a similar background population has been sparsely investigated. The aim of the study was to investigate if incidence rates (IRs) of VTE differed in patients who were alive at least 2 years after a cancer diagnosis without VTE compared with cancer-free references in a population-based cohort study. The study entry was 2 years after a first cancer diagnosis. For each cancer-exposed subject, five reference subjects were identified within the cohort. The IRs were calculated as number of VTEs per 1,000 person years (×10 -3 p-y) in total and in distinct cancer types and corresponding reference subjects. Incidence rate ratios (IRRs) were calculated by Poisson's regression. During a mean follow-up of 5.3 years, 110 VTEs occurred among the 7,288 cancer-exposed subjects and 321 VTEs occurred among the 36,297 identified reference subjects. The IR of VTE was higher for cancer-exposed subjects compared with reference subjects, IRs 3.7 × 10 -3 p-y, 95% CI: 3.1 to 4.5 and 1.9 × 10 -3 p-y, 95% CI: 1.7 to 2.2, respectively. IRs of VTE in most solid cancer types declined to almost the same level as in the reference subjects 2 years after cancer diagnosis, but remained higher in hematological cancers, IRR 4.0, 95% CI: 2.0 to 7.8.

A porcine in-vivo model of acute pulmonary embolism.

Acute pulmonary embolism (PE) is the third most common cardiovascular cause of death after acute myocardial infarction and stroke. Patients are, however, often under-treated due to the risks associated with systemic thrombolysis and surgical embolectomy. Novel pharmacological and catheter-based treatment strategies show promise, but the data supporting their use in patients are sparse. We therefore aimed to develop an in vivo model of acute PE enabling controlled evaluations of efficacy and safety of novel therapies. Danish Landrace pigs (n = 8) were anaesthetized and mechanically ventilated. Two pre-formed autologous PEs (PE1, PE2, 20 × 1 cm) were administered consecutively via the right external jugular vein. The intact nature and central location were visualized in situ by magnetic resonance imaging (MRI). The hemodynamic and biochemical responses were evaluated at baseline (BL) and after each PE by invasive pressure measurements, MRI, plus arterial and venous blood analysis. Pulmonary arterial pressure increased after administration of the PEs (BL: 16.3 ± 1.2, PE1: 27.6 ± 2.9, PE2: 31.6 ± 3.1 mmHg, BL vs. PE1: P = 0.0027, PE1 vs. PE2: P = 0.22). Animals showed signs of right ventricular strain evident by increased end systolic volume (BL: 60.9 ± 5.1, PE1: 83.3 ± 5.0, PE2: 99.4 ± 6.5 mL, BL vs. PE1: P = 0.0005, PE1 vs. PE2: P = 0.0045) and increased plasma levels of Troponin T. Ejection fraction decreased (BL: 58.9 ± 2.4, PE1: 46.4 ± 2.9, PE2: 37.3 ± 3.5%, BL vs. PE1: p = 0.0008, PE1 vs. PE2: P = 0.009) with a compensatory increase in heart rate preserving cardiac output and systemic blood pressure. The hemodynamic and biochemical responses were comparable to that of patients suffering from intermediate-high-risk PE. This porcine model mirrors the anatomical and physiologic changes seen in human patients with intermediate-high-risk PE, and may enable testing of future therapies for this disease.

Epidemiology of venous thromboembolism in hematological cancers: The Scandinavian Thrombosis and Cancer (STAC) cohort.

INTRODUCTION: Venous thromboembolism (VTE) is an important cause of morbidity and mortality in cancer patients, however the risk of VTE differs according to cancer type. Hematological cancers have varying phenotypes. Incidence rates (IR) of VTE in different hematological cancer types have not been investigated in a cancer-exposed subset of the general population. METHODS: In a population-based cohort, we estimated incidence rates of VTE among patients with six subtypes of hematological cancer and among age and sex matched reference subjects. RESULTS: During a mean follow-up of 4.8years, 30 objectively confirmed first-time symptomatic VTEs occurred among 838 subjects with hematological cancer. The IR of VTE was higher in all types of cancer except for indolent lymphoma but including chronic lymphocytic leukemia compared with reference subjects both during the first year after cancer diagnosis and 1-5years after diagnosis. IR of VTE for indolent lymphoma was not higher than controls. CONCLUSION: The IRs of VTE were increased in all types of hematological cancer (including chronic lymphocytic leukemia) compared with reference subjects except indolent lymphomas.