Prognostic markers in young patients with premature coronary heart disease

AbstractObjectivesTo evaluate the survival and prognostic implications of cardiovascular, inflammatory and prothrombotic risk factors in young patients with premature coronary heart disease (CHD).MethodsFollow-up data were obtained from 353 young patients with a first cardiac event (men ≤45 years and women ≤55 years). Baseline characteristics on traditional risk factors were collected at the time of the first event, and plasma levels of C-reactive protein (CRP), von Willebrand Factor (VWF), and fibrinogen were measured one to three months after the first event to exclude an acute phase response. We performed age and sex adjusted Cox regression analyses to assess the relationship between these factors and recurrent events with three different endpoints: all cause mortality, recurrent cardiac event (myocardial infarction or revascularisation procedure), and any recurrent event (cardiac event, cerebrovascular event or all cause mortality).ResultsDuring a total follow-up time of 1483 person years (mean 4.2 years), 11 patients died (3%), 42 patients had a recurrent cardiac event (12%), and 53 patients had any recurrent event (15%). CRP was associated with an increased risk of any recurrent event (HR 1.28[95% CI = 1.02–1.59] per unit increase in lnCRP). Also, both CRP (5.00[1.04–24.04]) and fibrinogen (5.04[1.05–24.23]) were associated with all cause mortality when levels were above the 50th percentile.ConclusionsFifteen percent of young patients with a first cardiac event have a recurrent event or die within a median follow-up of 4.2 years. In these young patients we have shown that, independently of cardiovascular risk factors, high CRP levels contribute to the risk of recurrent events, including all cause mortality, and high fibrinogen levels are associated with all cause mortality

Impact of COVID-19 pandemic on the quality of test output in haemostasis laboratories

Introduction: The high incidence of thrombotic events in patients with COVID-19 affects health care worldwide and results in an increased workload in haemostasis laboratories due to more frequent testing of D-dimer, haemostatic parameters and anti-Xa tests. However, the impact of this increase in assay requests on the quality of performance in haemostasis laboratories remains unclear. In this study, the impact of the COVID-19 pandemic on the quality of performance and management of haemostasis laboratories was evaluated. Methods: The impact on the quality of performance was studied using external quality assessment data from 2019 to 2020 derived from ECAT surveys. A questionnaire was sent to Dutch haemostasis laboratories to identify challenges and management strategies. Furthermore, the number of assays performed in 2019 and 2020 was supplied by four Dutch hospitals, located in regions with different disease incidence. Results: No differences in response rate nor the quality of the measurements were observed between the EQA surveys in 2019 and 2020. The questionnaire results showed a large increase of >25% in the number of test requests for anti-Xa, D-dimer and fibrinogen assays in 2020 compared to 2019. Extreme peaks in test requests were also observed in the four evaluated hospitals. Additionally, 84% of the respondents indicated that they had experienced increased work pressure, and increased sick leave was observed in 71% of the participating laboratories. Conclusions: The enormous increase in test requests, especially for D-dimer assays and anti-Xa activity, did not affect the quality of performance within haemostatic laboratories during the COVID-19 pandemic

Does difference between label and actual potency of factor VIII concentrate affect pharmacokinetic-guided dosing of replacement therapy in haemophilia A?

BACKGROUND: To account for interindividual variability in the pharmacokinetics (PK) of factor concentrates, PK‐guided dosing is increasingly implemented in haemophilia patients. Calculations are based on provided label potency, but legislation allows a potency difference of ±20% between label and actual potency. It is unknown if these differences affect PK guidance. AIM: Explore the effects of potency differences on individual factor VIII (FVIII) PK parameters and the prediction of FVIII trough levels of dosing regimens. METHODS: We analyzed individual preoperative PK profiling data from severe and moderate haemophilia A patients included in the OPTI‐CLOT randomized controlled trial. Label and actual potency were compared, with data on potency provided by pharmaceutical companies. For both potencies, individual PK parameters were estimated and concentration‐time curves were constructed by nonlinear mixed‐effects modelling. Finally, we explored the effect of both the identified and the maximum legislated potency difference on predicted FVIII trough levels infused in a low and high dose regimen. RESULTS: In 45/50 included patients, actual potency was higher than its label potency. The median potency difference was 6.0% (range ‐9.2% to 18.4%) and resulted in varying individual PK parameter estimates but practically identical FVIII concentration‐time curves. As expected, predicted FVIII trough levels were linearly correlated to the actual dose. CONCLUSION: It is not necessary to take potency differences into account when applying PK guidance of FVIII concentrates in haemophilia A patients. However, when the patient is switched to another FVIII batch after PK‐guided dosing, trough levels may deviate ±20% from calculations based on label dose

Tensile and Compressive Mechanical Behaviour of Human Blood Clot Analogues

Endovascular thrombectomy procedures are significantly influenced by the mechanical response of thrombi to the multi-axial loading imposed during retrieval. Compression tests are commonly used to determine compressive ex vivo thrombus and clot analogue stiffness. However, there is a shortage of data in tension. This study compares the tensile and compressive response of clot analogues made from the blood of healthy human donors in a range of compositions. Citrated whole blood was collected from six healthy human donors. Contracted and non-contracted fibrin clots, whole blood clots and clots reconstructed with a range of red blood cell (RBC) volumetric concentrations (5–80%) were prepared under static conditions. Both uniaxial tension and unconfined compression tests were performed using custom-built setups. Approximately linear nominal stress–strain profiles were found under tension, while strong strain-stiffening profiles were observed under compression. Low- and high-strain stiffness values were acquired by applying a linear fit to the initial and final 10% of the nominal stress–strain curves. Tensile stiffness values were approximately 15 times higher than low-strain compressive stiffness and 40 times lower than high-strain compressive stiffness values. Tensile stiffness decreased with an increasing RBC volume in the blood mixture. In contrast, high-strain compressive stiffness values increased from 0 to 10%, followed by a decrease from 20 to 80% RBC volumes. Furthermore, inter-donor differences were observed with up to 50% variation in the stiffness of whole blood clot analogues prepared in the same manner between healthy human donors

The association between human blood clot analogue computed tomography imaging, composition, contraction, and mechanical characteristics

Background Clot composition, contraction, and mechanical properties are likely determinants of endovascular thrombectomy success. A pre-interventional estimation of these properties is hypothesized to aid in selecting the most suitable treatment for different types of thrombi. Here we determined the association between the aforementioned properties and computed tomography (CT) characteristics using human blood clot analogues. MethodsClot analogues were prepared from the blood of 4 healthy human donors with 5 red blood cell (RBC) volume suspensions: 0%, 20%, 40%, 60% and 80% RBCs. Contraction was measured as the weight of the contracted clots as a percentage of the original suspension. The clots were imaged using CT with and without contrast to quantify clot density and density increase. Unconfined compression was performed to determine the high strain compressive stiffness. The RBC content was analysed using H&amp;E staining. Results The 5 RBC suspensions formed only two groups of clots, fibrin-rich (0% RBCs) and RBC-rich (&gt;90% RBCs), as determined by histology. The density of the fibrin-rich clots was significantly lower (31-38HU) compared to the RBC-rich clots (72-89HU), and the density increase of the fibrin-rich clots was significantly higher (82-127HU) compared to the RBC-rich clots (3-17HU). The compressive stiffness of the fibrin-rich clots was higher (178–1624 kPa) than the stiffness of the RBC-rich clots (6–526 kPa). Additionally, the degree of clot contraction was higher for the fibrin-rich clots (89–96%) compared to the RBC-rich clots (11–77%). ConclusionsCT imaging clearly reflects clot RBC content and seems to be related to the clot contraction and stiffness. CT imaging might be a useful tool in predicting the thrombus characteristics. However, future studies should confirm these findings by analysing clots with intermediate RBC and platelet content.</p

The association between human blood clot analogue computed tomography imaging, composition, contraction, and mechanical characteristics

Background Clot composition, contraction, and mechanical properties are likely determinants of endovascular thrombectomy success. A pre-interventional estimation of these properties is hypothesized to aid in selecting the most suitable treatment for different types of thrombi. Here we determined the association between the aforementioned properties and computed tomography (CT) characteristics using human blood clot analogues. MethodsClot analogues were prepared from the blood of 4 healthy human donors with 5 red blood cell (RBC) volume suspensions: 0%, 20%, 40%, 60% and 80% RBCs. Contraction was measured as the weight of the contracted clots as a percentage of the original suspension. The clots were imaged using CT with and without contrast to quantify clot density and density increase. Unconfined compression was performed to determine the high strain compressive stiffness. The RBC content was analysed using H&amp;E staining. Results The 5 RBC suspensions formed only two groups of clots, fibrin-rich (0% RBCs) and RBC-rich (&gt;90% RBCs), as determined by histology. The density of the fibrin-rich clots was significantly lower (31-38HU) compared to the RBC-rich clots (72-89HU), and the density increase of the fibrin-rich clots was significantly higher (82-127HU) compared to the RBC-rich clots (3-17HU). The compressive stiffness of the fibrin-rich clots was higher (178–1624 kPa) than the stiffness of the RBC-rich clots (6–526 kPa). Additionally, the degree of clot contraction was higher for the fibrin-rich clots (89–96%) compared to the RBC-rich clots (11–77%). ConclusionsCT imaging clearly reflects clot RBC content and seems to be related to the clot contraction and stiffness. CT imaging might be a useful tool in predicting the thrombus characteristics. However, future studies should confirm these findings by analysing clots with intermediate RBC and platelet content.</p

Evaluation of newer risk markers for coronary heart disease:The Rotterdam study

Design: Prospective cohort study in the general population of Rotterdam, the Netherlands (The Rotterdam Study). Methods: Data on measurements taken between 1997 and 2001 in 5,933 persons free of CHD (40.6% men; mean age 69.1 years) were collected. We studied the predictive ability of 12 newer risk markers (N-terminal pro-brain natriuretic peptide [NT-proBNP] levels, von Willebrand factor antigen levels, fibrinogen levels, chronic kidney disease, leukocyte count, C-reactive protein levels, homocysteine levels, uric acid levels, coronary artery calcification [CAC] scores obtained by means of CT, carotid intima-media thickness, peripheral arterial disease, and aortic pulse wave velocity). The predictive value was determined by adding a newer marker to a prediction model that was based on traditional cardiovascular risk factors. Results: Risk discrimination improved the most with the addition of CAC scores. A net 23.5% of the individuals who developed CHD were reclassified to a higher risk category, but also 4.2% of those who did not develop CHD. This resulted in a net reclassification improvement (NRI) of 0.193. The CAC score was followed by NT-proBNP (NRI 0.076) in terms of the most improvement to risk classification. Improvements in risk predictions with the other newer markers were marginal. Conclusions: Classification of CHD risk predictions improved most with the addition of the CAC scores to the risk model. Further research is needed to assess whether refinements in risk prediction will actually lead to more effective prevention of cardiovascular disease together with justifiable costs and efforts.</p

Evaluation of newer risk markers for coronary heart disease:The Rotterdam study

Design: Prospective cohort study in the general population of Rotterdam, the Netherlands (The Rotterdam Study). Methods: Data on measurements taken between 1997 and 2001 in 5,933 persons free of CHD (40.6% men; mean age 69.1 years) were collected. We studied the predictive ability of 12 newer risk markers (N-terminal pro-brain natriuretic peptide [NT-proBNP] levels, von Willebrand factor antigen levels, fibrinogen levels, chronic kidney disease, leukocyte count, C-reactive protein levels, homocysteine levels, uric acid levels, coronary artery calcification [CAC] scores obtained by means of CT, carotid intima-media thickness, peripheral arterial disease, and aortic pulse wave velocity). The predictive value was determined by adding a newer marker to a prediction model that was based on traditional cardiovascular risk factors. Results: Risk discrimination improved the most with the addition of CAC scores. A net 23.5% of the individuals who developed CHD were reclassified to a higher risk category, but also 4.2% of those who did not develop CHD. This resulted in a net reclassification improvement (NRI) of 0.193. The CAC score was followed by NT-proBNP (NRI 0.076) in terms of the most improvement to risk classification. Improvements in risk predictions with the other newer markers were marginal. Conclusions: Classification of CHD risk predictions improved most with the addition of the CAC scores to the risk model. Further research is needed to assess whether refinements in risk prediction will actually lead to more effective prevention of cardiovascular disease together with justifiable costs and efforts.</p

Absence of COVID-19-associated changes in plasma coagulation proteins and pulmonary thrombosis in the ferret model

BACKGROUND: Many patients who are diagnosed with coronavirus disease 2019 (COVID-19) suffer from venous thromboembolic complications despite the use of stringent anticoagulant prophylaxis. Studies on the exact mechanism(s) underlying thrombosis in COVID-19 are limited as animal models commonly used to study venous thrombosis pathophysiology (i.e. rats and mice) are naturally not susceptible to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Ferrets are susceptible to SARS-CoV-2 infection, successfully used to study virus transmission, and have been previously used to study activation of coagulation and thrombosis during influenza virus infection. OBJECTIVES: This study aimed to explore the use of (heat-inactivated) plasma and lung material from SARS-CoV-2-inoculated ferrets studying COVID-19-associated changes in coagulation and thrombosis. MATERIAL AND METHODS: Histology and longitudinal plasma profiling using mass spectrometry-based proteomics approach was performed. RESULTS: Lungs of ferrets inoculated intranasally with SARS-CoV-2 demonstrated alveolar septa that were mildly expanded by macrophages, and diffuse interstitial histiocytic pneumonia. However, no macroscopical or microscopical evidence of vascular thrombosis in the lungs of SARS-CoV-2-inoculated ferrets was found. Longitudinal plasma profiling revealed minor differences in plasma protein profiles in SARS-CoV-2-inoculated ferrets up to 2 weeks post-infection. The majority of plasma coagulation factors were stable and demonstrated a low coefficient of variation. CONCLUSIONS: We conclude that while ferrets are an essential and well-suited animal model to study SARS-CoV-2 transmission, their use to study SARS-CoV-2-related changes relevant to thrombotic disease is limited

Effects of Ambient Air Pollution on Hemostasis and Inflammation

BACKGROUND: Air pollution has consistently been associated with increased morbidity and mortality due to respiratory and cardiovascular disease. Underlying biological mechanisms are not entirely clear, and hemostasis and inflammation are suggested to be involved. OBJECTIVES: Our aim was to study the association of the variation in local concentrations of airborne particulate matter (PM) with aerodynamic diameter < 10 mu m, carbon monoxide, nitrogen monoxide, nitrogen dioxide, and ozone with platelet aggregation, thrombin generation, fibrinogen, and C-reactive protein (CRP) levels in healthy individuals. METHODS: From 40 healthy volunteers, we collected 13 consecutive blood samples within a 1-year period and measured light-transmittance platelet aggregometry, thrombin generation, fibrinogen, and CRP. We performed regression analysis using generalized additive models to study the association between the hemostatic and inflammatory variables, and local environmental concentrations 0 air pollutants for time lags within 24 hr before blood sampling or 24-96 hr before blood sampling. RESULTS: In general, air pollutants were associated with platelet aggregation [average, +8% per interquartile range (IQR), p < 0.01] and thrombin generation (average, +1% per IQR, p < 0.015). Platelet aggregation was not affected by in vitro incubation of plasma with PM. We observed no relationship between any of the air pollutants and fibrinogen or CRP levels. CONCLUSIONS:. Air pollution increased platelet aggregation as well as coagulation activity but had no clear effect on systemic inflammation. These prothrombotic effects may partly explain the relationship between air pollution and the risk of ischemic cardiovascular disease