Marcus Lind

Thrombomodulin as a Marker for Bleeding Complications During Warfarin Treatment

BACKGROUND The major adverse effect of warfarin treatment is hemorrhage. Several risk factors for bleeding complications are also risk factors for thromboembolic events, making the clinical decision to initiate or withhold anticoagulant treatment difficult. Specific markers that solely identify patients at high risk of bleeding would have great clinical impact. This study aimed to test if thrombomodulin (TM) concentrations were associated with bleeding complications, cardiovascular events, or mortality in long-term anticoagulant-treated patients. METHODS In a longitudinal cohort study we followed up 719 patients receiving warfarin treatment for a mean duration of 4.2 years. All bleeding complications causing hospitalization were registered and classified. Soluble TM antigen (sTM) concentration in plasma was measured with an enzyme-linked immunosorbent assay method. RESULTS During the follow-up time, 113 clinically relevant bleeding events and 73 major bleeding events occurred. Increased concentration of sTM was associated with both clinically relevant bleeding and major bleeding events after adjustment for age. In the multivariable models, hazard ratios for the highest tertiles compared with the lowest were 2.29 (95% confidence interval, 1.35-3.89) and 2.33 (95% confidence interval, 1.21-4.48), respectively. No association between sTM concentration and nonfatal ischemic cardiovascular events or all-cause mortality was found. CONCLUSIONS Increased levels of sTM are associated with bleeding complications during warfarin treatment but not with cardiovascular events or all-cause mortality. Soluble TM antigen concentration has potential as a new specific marker to identify patients at high risk of bleeding during warfarin treatment.

Von Willebrand factor predicts major bleeding and mortality during oral anticoagulant treatment.

Abstract.  Lind M, Boman K, Johansson L, Nilsson TK, Slunga Järvholm L, Jansson J‐H (Address: Department of Public Health and Clinical Medicine, Umeå University; Department of Clinical Chemistry, Örebro University Hospital). Von Willebrand factor predicts major bleeding and mortality during oral anticoagulant treatment. J Intern Med 2012; 271: 239–246.

D-dimer predicts major bleeding, cardiovascular events and all-cause mortality during warfarin treatment

OBJECTIVES Previous studies have shown that biomarkers in blood plasma can predict bleeding complications during anticoagulant treatment as well as thromboembolic events and may improve existing risk stratification schemes in patients on or considered for oral anticoagulant treatment. The aim of this study was to investigate if levels of d-dimer, tissue plasminogen activator (tPA) and its complex with plasminogen inhibitor type 1 (tPA/PAI-1 complex) can predict major bleedings, cardiovascular events and all-cause mortality in patients with warfarin treatment. DESIGN AND METHODS In a longitudinal cohort study, 719 patients on oral anticoagulant treatment were followed for a total of 3001 treatment years. Major bleeding, stroke, arterial emboli, myocardial infarction and death were recorded and classified. Blood samples collected at baseline were analyzed for d-dimer, tPA, and tPA/PAI-1 complex. RESULTS In multivariate Cox regression analysis, high levels of d-dimer were associated with major bleeding (HR 1.27 per SD; 95% CI: 1.01-1.60), cardiovascular events (HR 1.23 per SD; 95% CI: 1.05-1.45) and all-cause mortality (HR 1.25 per SD; 95% CI: 1.06-1.47). Neither tPA nor the tPA/PAI-1 complex was associated with major bleeding, cardiovascular events or all-cause mortality. CONCLUSION We conclude that high levels of d-dimer predict major bleeding, cardiovascular events and all-cause mortality during warfarin treatment.

von Willebrand activation factor as a marker of mortality, cardiovascular events, and bleeding complications in patients treated with oral anticoagulants

BACKGROUND Serious bleeding is a frequent and feared treatment complication in patients treated with oral anticoagulants (OACs). Levels of von Willebrand factor (VWF) antigen have been linked to the risk of bleeding complications, mortality, and cardiovascular events. OBJECTIVES In this longitudinal cohort study of evaluating patients treated with OACs, we aimed to evaluate the relationship between VWF displaying a glycoprotein Ib binding conformation (VWF activation factor) and the risk of cardiovascular events, bleeding complications, or all-cause mortality. MATERIALS AND METHODS Blood samples were collected at baseline in 356 patients on OACs. Patients were followed for an average of 48 months and bleeding complications leading to admission to hospital or death, cardiovascular events (myocardial infarction, ischemic stroke, and peripheral arterial emboli), and all-cause mortality were recorded and classified. RESULTS During the study period, 47 bleeding complications, 84 cardiovascular events, and 97 deaths occurred. In multivariate Cox regression analyses, VWF activation factor was significantly associated with all-cause mortality (HR 1.62; 95% CI: 1.25-2.08) and cardiovascular events (HR 1.28; 95% CI: 1.01-1.63). There was no association observed between VWF activation factor and bleeding complications. CONCLUSIONS Patients with high levels of VWF activation factor had an increased risk of cardiovascular events and all-cause mortality during OAC treatment. The selectivity for thrombotic complications adds to the potential value of VWF activation factor as a biomarker or pharmacological target.

Cystatin C and creatinine as markers of bleeding complications, cardiovascular events and mortality during oral anticoagulant treatment

INTRODUCTION Impaired kidney function has been linked to both ischemic events as well as bleeding complications in several clinical conditions. Our aim was to investigate if cystatin C, creatinine and calculated glomerular filtration rate (eGFR) were related to future risk of bleeding complications, cardiovascular events or all-cause mortality during oral anticoagulant treatment. MATERIALS AND METHODS In a cohort study, 719 patients on long-term vitamin K antagonist (VKA) treatment were followed for a mean of 4.2 years. Blood sampling was taken at inclusion and patients were followed prospectively. Cystatin C and creatinine were analysed and eGFR was calculated. All medical records were reviewed. Major bleeding events, myocardial infarctions, strokes, arterial emboli, and deaths were recorded and classified. RESULTS After adjustment for age, no association between cystatin C, creatinine or eGFR and major bleeding was found. Cystatin C was independently associated with cardiovascular events (hazard ratio 1.50 (95% CI: 1.27-1.77)) and all-cause mortality (hazard ratio 1.62 (95% CI: 1.38-1.90)).Creatinine was only associated with all-cause mortality, while eGFR was not associated with any of the outcomes. CONCLUSIONS Our findings underscore the superiority of cystatin C as a marker of cardiovascular risk compared to creatinine or eGFR. VKA-treated patients with increased cystatin C levels should be considered to be at an increased risk of cardiovascular events, and not bleeding complications.

Fasting plasma glucose, oral glucose tolerance test, and the risk of first-time venous thromboembolism. A report from the VEINS cohort study

INTRODUCTION It remains unclear whether high plasma glucose levels are associated with venous thromboembolism (VTE). This study investigated the association between fasting plasma glucose (FPG), oral glucose tolerance test (two-hour post-load plasma glucose (2HPG)), diabetes, and VTE. MATERIALS AND METHODS The population-based, prospective Venous thromboEmbolism In Northern Sweden (VEINS) cohort study included 108,025 residents of Västerbotten County in northern Sweden. The participants were aged 30 to 60 years and had no previous VTE events. They were included from 1985 onwards and were followed until a VTE event, death, emigration, or the study end on September 5, 2014. All underwent a health examination that measured weight, height, FPG, and 2HPG and included a questionnaire regarding smoking, education level, and history of diabetes. Potential VTE events were identified by an extensive diagnosis registry search and were validated by reviewing medical records and radiology reports. RESULTS An objectively verified first-time VTE event was experienced by 2054 participants during 1,496,669 person-years of follow-up. In univariable analysis, there were associations between FPG, 2HPG, diabetes, and the risk of VTE. These associations disappeared after adjustment for potential confounders (age, sex, body mass index, cancer at inclusion, education level, smoking, and hypertension). The adjusted hazard ratios were 1.01 (95% confidence interval 0.83-1.23) for diabetes, 1.01 for each standard deviation of FPG (95% confidence interval 0.97-1.05), and 0.96 for each standard deviation of 2HPG (95% confidence interval 0.91-1.00). CONCLUSIONS There were no independent associations between FPG, 2HPG, diabetes, and future risk of VTE.

Positive predictive value and misclassification of diagnosis of pulmonary embolism and deep vein thrombosis in Swedish patient registries

Purpose To validate diagnoses of pulmonary embolism (PE) and deep vein thrombosis (DVT) in administrative registries. We also estimated the frequency of misclassified PE and DVT events. Patients and methods A registry search for ICD codes representing PE and DVT was performed between 1985 and 2014 in a large population-based cohort in northern Sweden. An additional search using an extended set of ICD codes was performed to identify misclassified events. Diagnoses were validated manually by reviewing medical records and radiology reports. Results Searching ICD codes in the National Patient Registry and Cause of Death Registry identified 2,450 participants with a first-time diagnosis of PE or DVT. The positive predictive value (PPV) for a diagnosis of PE or DVT was 80.7% and 59.2%, respectively. For the period of 2009 to 2014, the PPV was higher for PE (85.8%) but lower for DVT (54.1%). Misclassification occurred in 16.4% of DVT events and 1.1% of PE events. Conclusion Registry-based data on PE, especially in recent years, are of acceptable quality and can be considered for use in registry-based studies. For DVT, we found that data were of low quality in regards to both PPV and misclassification and should not be used without validation.

Factor XII as a Risk Marker for Hemorrhagic Stroke: A Prospective Cohort Study

Background: Coagulation factor XII (FXII) is involved in pathological thrombus formation and is a suggested target of anticoagulants. It is unclear whether FXII levels are correlated with cardiovascular risk factors and whether they are associated with myocardial infarction or ischemic or hemorrhagic stroke. The aim of this study was to investigate the correlation between FXII and cardiovascular risk factors in the general population. We also aimed to study the associations between FXII levels and future myocardial infarction and ischemic and hemorrhagic stroke. Methods: This prospective cohort study measured FXII levels in 1,852 randomly selected participants in a health survey performed in northern Sweden in 1994. Participants were followed until myocardial infarction, stroke, death, or until December 31, 2011. Results: During the median follow-up of 17.9 years, 165 individuals were diagnosed with myocardial infarction, 108 with ischemic stroke, and 30 with hemorrhagic stroke. There were weak correlations between FXII and body mass index, cholesterol, and hypertension. There was no association between FXII and myocardial infarction or ischemic stroke, neither in univariable Cox regression analysis nor after adjustment for age, sex, smoking, body mass index, cholesterol, hypertension, and diabetes. In univariable Cox regression analysis, the hazard ratio for the association between FXII levels and hemorrhagic stroke was 1.42 per SD (95% confidence interval: 0.99–2.05). In the multivariable model, higher levels of FXII were associated with increased risk of hemorrhagic stroke (hazard ratio 1.51 per SD; 95% confidence interval: 1.03–2.21). Conclusion: We found an independent association between FXII levels and the risk of hemorrhagic stroke, but not between FXII levels and ischemic stroke or myocardial infarction.

High homocysteine and low folate plasma concentrations are associated with cardiovascular events but not bleeding during warfarin treatment

Abstract Background: Previous studies have shown that homocysteine and folate levels in plasma are associated with risk for cardiovascular events and mortality. The aim of this study was to investigate if plasma concentrations of total homocysteine and folate can predict major bleeding, cardiovascular events, and all-cause mortality in patients being treated with warfarin. Methods: In a longitudinal cohort study, 719 patients who were taking warfarin were followed for 3001 treatment years. The following were recorded and classified: major bleeding; cardiovascular events including stroke, arterial emboli, and myocardial infarction (MI); and mortality. Blood samples collected at baseline were analysed for plasma homocysteine and folate levels. Results: After adjustment for age, C-reactive protein, and creatinine, high homocysteine levels were associated with cardiovascular events [hazard ratio (HR) 1.23 per standard deviation (SD); 95% confidence interval (CI): 1.03–1.47], MI (HR 1.38 per SD; 95% CI: 1.03–1.85), and all-cause mortality (HR 1.41 per SD; 95% CI: 1.19–1.68). The highest tertile of folate compared to the lowest tertile was associated with decreased risk for both cardiovascular events (HR 0.64; 95% CI: 0.43–0.91) and MI (HR 0.45; 95% CI: 0.21–0.97). There was no association between major bleeding and homocysteine or folate levels. Conclusions: In patients receiving warfarin treatment, high homocysteine and low folate plasma concentrations are associated with increased risk for cardiovascular events but not major bleeding. For homocysteine levels, there is also an association with all-cause mortality.