Changes in Haemostatic Factors and Activation Products after Exercise in Healthy Subjects with Different Ages

Causal relationship between moderate to vigorous physical activity and venous thromboembolism

Previous studies have shown conflicting results about the impact of moderate to vigorous physical activity on the risk of venous thromboembolism (VTE).  Using Mendelian randomization, we assessed whether moderate to vigorous physical activity causally affects VTE from genetic level. Genetic instruments associated with moderate to vigorous physical activity at the genome-wide significance level (P < 5×10^- 8) were selected from the UK Biobank. Summary-level data for VTE were obtained from the FinnGen consortium. Univariable and multivariable Mendelian randomization analyses were conducted. Genetically predicted moderate to vigorous physical activity had no effect on VTE [odds ratio (OR) = 1.08; 95% confidence interval (CI) 0.66-1.78; P = 0.75] under a multiplicative random-effects inverse-variance weighted model. MR-Egger (OR = 0.20; 95% CI 0.01-4.70; P = 0.33), weighted median (OR = 1.08; 95% CI 0.52-2.25; P = 0.84), simple mode (OR = 2.53; 95% CI 0.59-10.92; P = 0.23), weighted mode (OR = 2.21; 95% CI 0.50-9.74; P = 0.31), and multivariable Mendelian randomization (OR = 0.74; 95% CI 0.46-1.19; P = 0.22) also yielded no significant association. The overall estimate was not influenced by individual single nucleotide polymorphism. No evidence of heterogeneity or horizontal pleiotropy was observed. Therefore, moderate to vigorous physical activity had no causal association with VTE in the general population.

Effects of Four-Week Rehabilitation Program on Hemostasis Disorders in Patients with Spinal Cord Injury

Background: Patients with spinal cord injury (SCI) exhibit hemostasis disorders. This study aims at assessing the effects of a 4-week rehabilitation program on hemostasis disorders in patients with SCI. Methods: Seventy-eight in-patients undergoing a 4-week rehabilitation were divided into three groups based on time elapsed since SCI: I (3 weeks–3 months), II (3–6 months), and III (>6 months). Tissue factor (TF), tissue factor pathway inhibitor (TFPI), thrombin–antithrombin complex (TAT) and D-dimer levels, antithrombin activity (AT), and platelet count (PLT) were measured on admission and after rehabilitation. Results: Rehabilitation resulted in an increase in TF in group III (p < 0.050), and decrease in TFPI (p < 0.022) and PLT (p < 0.042) in group II as well as AT in group I (p < 0.009). Compared to control group without SCI, TF, TFPI, and TAT were significantly higher in all SCI groups both before and after rehabilitation. All SCI groups had elevated D-dimer, which decreased after rehabilitation in the whole study group (p < 0.001) and group I (p < 0.001). Conclusion: No decrease in activation of TF-dependent coagulation was observed after a 4-week rehabilitation regardless of time elapsed since SCI. However, D-dimer levels decreased significantly, which may indicate reduction of high fibrinolytic potential, especially when rehabilitation was done <3 months after SCI.

Effects of storage over a 36-month period on coagulation factors in a canine plasma product obtained by use of plasmapheresis

OBJECTIVE

To evaluate stability of coagulation factors in canine plasma obtained by use of plasmapheresis and stored over a 36-month period.

SAMPLE

Canine plasma obtained by use of plasmapheresis acquired from a commercial blood bank.

PROCEDURES

Coagulation testing for fibrinogen concentration and activity of factors II, V, VII, VIII, and IX and von Willebrand factor was performed on canine plasma obtained by use of plasmapheresis. Samples were obtained for testing at 6-month intervals from plasma stored for up to 36 months.

RESULTS

A simple mixed linear regression model was created for each analysis. Median value for the fibrinogen concentration was > 150 mg/dL for all time points, except at 467, 650, and 1,015 days of storage. Median value for factor VIII was > 70% only at 650 days. Median value for factor V was > 50% through 650 days. Median value for factors VII and X was > 50% through 833 days, and median value for factors II and VII was > 50% through 1,015 days. Median value for von Willebrand factor was > 50% for the entire study (1,198 days). Median value for factor X was always < 50%.

CONCLUSIONS AND CLINICAL RELEVANCE

Coagulation factors degraded over time at variable rates, and all labile factors remained at > 50% activity for longer than 1 year. Plasma collected by plasmapheresis potentially offers prolonged life span of some clotting factors. Plasmapheresis is an acceptable form of canine plasma collection for transfusion purposes, and further studies should be performed to determine all of its benefits.

Hemoconcentration and hemostasis during acute stress: interacting and independent effects

BACKGROUND

Acute psychological stress can produce significant hemoconcentration as well as prothrombotic changes in blood, both of which may have potentially harmful effects on the cardiovascular system. It is unclear whether these effects are independent or have influence on each other.

PURPOSE

This review discusses research investigating the effects of acute psychological stress on hemoconcentration and hemostasis and explores future directions for psychohematology research. Physiology, associations with cardiovascular disease, and relationships between acute psychological stress are discussed independently for hemoconcentration and hemostasis, followed by an examination of the effects of stress-hemoconcentration on hemostasis.

CONCLUSIONS

Traditional methods of adjusting for stress-hemoconcentration effects (e.g., calculated plasma volume or hematocrit level corrections) may not be appropriate when examining stress-induced changes in hemostasis. The effects of acute stress on hemostasis should be examined in conjunction with hemoconcentration.

D-dimer assays for the identification of menstrual blood

A method to reliably distinguish menstrual blood from blood in the normal circulation (peripheral blood) would be of considerable use in the forensic analysis and interpretation of evidence in sexual offence investigations. Previous attempts to address this issue have explored microscopy, lactate dehydrogenase isozyme identification, mRNA and miRNA profiling, and identification of the products of fibrinolysis. Here, four assays for D-dimer, a terminal degradation product of fibrinolysis, are evaluated for their specificity and sensitivity in detection of menstrual blood. In addition the effect of exercise, and sample storage upon D-dimer detection was investigated. Comparison of different assays revealed significant differences in results given. Nevertheless, no positive results for D-dimer were obtained using peripheral blood, mixtures of peripheral blood with semen, or peripheral blood taken from donors after moderate exercise. D-dimer was found to be detectable in 100% of menstrual blood samples after 1 week at room temperature and also in samples stored long-term (>3 years) at -20 °C. D-dimer may be an effective, simple to use tool for the presumptive identification of menstrual blood identification.

The effect of the acute submaximal exercise on thrombin activatable fibrinolysis inhibitor levels in young sedentary males

Depending on type, duration, and intensity of the exercise, changes occur in hemostasis. In this study, we evaluated the changes in the parameters of coagulation and fibrinolytic systems that happened after the submaximal aerobic exercises by bicycle ergomater. Twelve healthy male participants whose ages were between 21 and 28 have been included. The venous samples have been drawn before the exercise as well as at the 0 th, 15th, and 60th minutes after the submaximal exercise. The values of prothrombin time (PT), active partial thromboplastin time (aPTT), D-dimer, fibrinogen, plasminogen activator inhibitor 1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI) have been measured. Plasminogen activator inhibitor 1 values have shown an insignificant increase after exercise (P = .328), whereas, it has decreased significantly during the resting period (P = .033) Postexercise 15th and 60th minutes TAFI values have decreased significantly comparing to basal and postexercise (0 th minute) values (P = .001). Fibrinolytic system activation is observed after acute submaximal aerobic exercise of sedentary healthy participants.

Blood coagulation and fibrinolysis in healthy, untrained subjects: effects of different exercise intensities controlled by individual anaerobic threshold

The influence of different exercise intensities on haemostasis in healthy, untrained subjects has not been intensively studied. We investigated untrained subjects for alterations in coagulation and fibrinolysis induced by two exercise intensities, precisely controlled by individual anaerobic threshold (IAT). Twenty-five healthy, untrained non-smokers (age 25 ± 3 years; relative VO(2) peak 43.1 ± 5.2 ml/kg/min) underwent exercise tests at 80% (moderate) and 100% (strenuous) of IAT for 60 min. Blood samples were taken after 30 min rest and immediately after exercise. The present results reveal that an exercise intensity at 100% IAT induces a more pronounced coagulation activity than exercises at 80% IAT. 100% IAT led to a significant higher increase in FVIII (80% IAT 85 ± 33 to 114 ± 30% vs. 100% IAT 81 ± 20 to 132 ± 29%) and TAT (80% IAT 2.5 ± 1.4 to 2.9 ± 1.0 μg/l vs. 100% IAT 2.6 ± 1.0 to 5.4 ± 4.2 μg/l). Furthermore, both exercises affected fibrinolysis, but it was significantly higher at 100% IAT (tPA activity; 80% IAT 0.44 ± 0.17 to 4.65 ± 2.67 U/ml vs. 100% IAT 0.43 ± 0.19 to 6.47 ± 3.97 U/ml). The data show that fibrinolytic activity is significantly elevated already after moderate exercise (80% IAT). After strenuous exercise (100% IAT), coagulation is more sharply enhanced together with a higher increase of fibrinolysis in comparison with 80% IAT. However, haemostasis seems to be in balance after moderate as well as after strenuous exercise intensity in healthy, untrained participants. Based on these data, exercise-induced changes of both haemostatic systems should also be tested in patients with cardiovascular diseases in order to be in a position to give recommendations for endurance training modalities in rehabilitation training.

Exercise-Induced Hemostatic Alterations Are Detectable by Rotation Thrombelastography (ROTEM): A Marathon Study

Rotation thrombelastography (ROTEM) provides a whole blood assay that allows the assessment of plasmic- and platelet-related hemostasis in a single-step procedure. In our current study, we focused on the capability of the method to detect hemostatic alterations induced by physical exercise, enrolling 33 healthy participants of the Dusseldorf Marathon 2006. Venous blood drawn immediately before and after finishing the marathon was analyzed by a rotational thrombelastograph (Pentapharm, Munich, Germany). On initiation of blood coagulation by recalcification, standard ROTEM parameters were determined. Comparison of the results obtained before and after the physical exercise was performed using the Student t test for paired samples. As a result, the mean clotting time (CT) determined from blood samples obtained immediately after the marathon was significantly shorter (662.9 ± 67.8 seconds vs 505.6 ± 97.3 seconds, P = .002) and the mean maximal clot firmness was significantly broader (48.4 ± 6.6 mm vs 51.5 ± 4.5 mm, P = .0004) when compared to results obtained before the physical exercise. Differences between mean clot formation times (CFTs; 280.6 + 96 seconds vs 270.4 ± 73.8 seconds) and mean α angles (45.9° ± 8° vs 47.8° ± 5.8°) before and after the marathon were not statistically significant. Remarkably, some participants showed opposed results, particularly prolongation of CT and narrowing of maximum clot firmness (MCF). Our study demonstrates that ROTEM is sensitive to exercise-induced hemostatic alterations. The method appears to be capable of detecting even distinct changes in hemostasis in a single-step procedure. Further analyses are needed to clarify which hemostasis parameters influence ROTEM results and which ROTEM results are independent predictors of exercise-induced alterations of plasmic and platelet function. This might help to explain interindividual differences in exercise-induced alterations of hemostasis.

Coagulation and fibrinolysis are in balance after moderate exercise in middle-aged participants

Increased age is associated with a higher risk of thrombotic events. The aim of this study was to investigate the age-related changes in hemostasis before and after moderate exercise controlled by individual anaerobic threshold as recommended for rehabilitation training. In this study, 24 young (25 +/- 1 years) and 24 middle-aged healthy nonsmokers (48 +/- 1 years) underwent an individualized exercise test with 80% of individual anaerobic threshold (young individuals: 127 +/- 6 W; middle-aged individuals: 128 +/- 5 W; values are expressed as mean +/- standard error of mean) for 60 minutes. The blood samples were collected before and after the exercise. The age-related higher (P < or = .05) levels could be detected in factors II, VII, VIII, IX, XI, XII, prothrombin fragment 1+2, in tissue plasminogen activator antigen and activity, as well as in plasminogen. The relative exercise-induced increases in these parameters were similar in both groups, although beginning at a higher level for those in the middle-aged group.A statistically enhanced increase after exercise in the middle-aged group could be shown in prothrombin fragment 1+2 (young individuals: 98 +/- 6 to 102 +/- 6 pmol/L; middle-aged individuals: 138 +/- 7 to 156 +/- 8 pmol/L) and in thrombin-antithrombin complex (young individuals: 2.2 +/- 0.1 to 3.1 +/- 0.2 microg/L; middle-aged individuals: 2.4 +/- 0.3 to 3.9 +/- 0.6 microg/L); the latter only showing a tendency. The data show the age-related changes with a rise in blood coagulation and fibrinolysis in a healthy middle-aged group compared with younger participants. Moderate exercise leads to comparably relative increases in hemostatic parameters but starting at higher levels. However, the exercise-induced thrombin generation (prothrombin fragment 1+2) is enhanced in the middle-aged participants in comparison with younger participants, but may be compensated by a sufficient fibrinolysis, and therefore the hemostatic system remains in balance.

Exercise-induced shear stress is associated with changes in plasma von Willebrand factor in older humans

Shear stress is the frictional force of blood against the endothelium, a stimulus for endothelial activation and the release of von Willebrand factor (vWF). This study tested the hypothesis that the increase in shear stress associated with exercise correlates with plasma vWF. Young (n = 14, 25.7 +/- 5.4 years) and older (n = 13, 65.6 +/- 10.7 years) individuals participated in 30 min of dynamic handgrip exercise at a moderate intensity. Brachial artery diameter and blood flow were measured using ultrasound Doppler and blood samples were collected before, immediately after, and following 30 min of recovery from exercise with plasma levels of vWF. Plasma levels of vWF increased (P < 0.05) by 6 +/- 2% in young individuals and 4 +/- 1% in older individuals immediately after exercise. The change in plasma vWF was linearly correlated with the increase in shear stress during exercise in older individuals (post-exercise: r = 0.78, 30 min recovery: r = 0.77, P < 0.01), but no association was found in the young individuals. These changes in plasma levels of vWF in humans suggest that aging influences endothelial activation and hemostasis.

Risk of future arterial cardiovascular events in patients with idiopathic venous thromboembolism

Venous and arterial thromboses have traditionally been considered distinct pathophysiologic entities. However, the two disorders have many features in common, and there is evidence that persons with venous thrombosis may be at greater risk for arterial events. The pathogenesis of both disorders includes endothelial injury, platelet activation, elevated levels of intrinsic clotting factors and inflammatory markers, increased fibrinogen, and impaired fibrinolysis. In addition, older age, obesity, dyslipidemia, and smoking predispose to both venous and arterial thrombosis. While the evidence that arterial disease is a risk factor for venous thrombosis is inconclusive, arterial disease does appear to occur with a modestly increased frequency in patients with a history of venous thromboembolism. Reported odds ratios in such patients were 1.2 for myocardial infarction, 1.3 for stroke, 2.3 for carotid plaque, and 4.3 for coronary calcification. Of note, in persons under age 40 with unprovoked venous thrombosis, the odds ratio for acute myocardial infarction was as high as 3.9. In general, however, venous disease is considered to be a weak risk factor for arterial thrombosis, and the use of agents specifically targeted to the prevention of heart attack or stroke in the majority of persons with VTE cannot be recommended at present.

Prothrombotic changes with acute psychological stress: combined effect of hemoconcentration and genuine coagulation activation

INTRODUCTION

Acute psychosocial stress accelerates blood coagulation and elicits hemoconcentration which mechanisms are implicated in acute coronary thrombotic events. We investigated the extent to which the change in prothrombotic measures with acute stress reflects hemoconcentration and genuine activation of coagulation.

MATERIAL AND METHODS

Twenty-one middle-aged healthy men underwent three sessions of a combined speech and mental arithmetic task with one-week intervals. Coagulation and plasma volume were assessed at baseline, immediately post-stress, and 45 min post-stress at sessions one and three. Measures of both visits were aggregated to enhance robustness of individual biological stress responses. Changes in eight coagulation measures with and without adjustment for simultaneous plasma volume shift were compared.

RESULTS

From baseline to immediately post-stress, unadjusted levels of fibrinogen (p=0.028), clotting factor VII activity (FVII:C) (p=0.001), FVIII:C (p<0.001), FXII:C (p<0.001), and von Willebrand factor (VWF) (p=0.008) all increased. Taking into account hemoconcentration, fibrinogen (p=0.020) and FVII:C levels (p=0.001) decreased, activated partial prothrombin time (APPT) shortened (p<0.001) and prothrombin time (PT) was prolonged (p<0.001). Between baseline and 45 min post-stress, unadjusted (p=0.050) and adjusted (p=0.001) FVIII:C levels increased, adjusted APTT was prolonged (p=0.017), and adjusted PT was shortened (p=0.033). D-dimer levels did not significantly change over time.

CONCLUSIONS

Adjustment for stress-hemoconcentration altered the course of unadjusted levels of several prothrombotic factors. After adjustment for hemoconcentration, APPT was shortened immediately post-stress, whereas 45 min post-stress, FVIII:C was increased and PT was shortened. Procoagulant changes to acute stress may reflect both hemoconcentration and genuine activation of coagulation molecules and pathways.

The immediate effect of aerobic exercise on haemostatic parameters in patients with recently diagnosed mild to moderate essential hypertension

BACKGROUND

Exercise is frequently recommended for the treatment of patients with arterial hypertension. Previous studies have shown an enhanced coagulation state after exercise. Our study investigates the alterations observed after a single session of submaximal aerobic exercise concerning coagulation, fibrinolysis, platelet activation as well as endothelial function in patients with recently diagnosed essential hypertension.

METHODS

Twenty non-diabetic patients with recently diagnosed essential hypertension participated in a 45 min submaximal exercise test on a bicycle ergometer. Blood samples were drawn before and after exercise in order to determine parameters of coagulation activation (Prothrombin time [PT], activated Partial Thromboplastin time [aPTT], fibrinogen, D-Dimers, prothrombin fragments 1 + 2 [PF1+2], thrombin-antithrombin III complex [TAT] and factors VII, VIII and XII), platelet activation (Platelet count, Platelet factor 4 [PF4] and beta-thromboglobulin [beta-TG]), fibrinolysis activation (Plasmin-a(2) antiplasmin complex, PAP) and endothelial function (soluble Thrombomodulin [sTM] and von Willebrand factor [vWf]). Soluble P-selectin served as a marker for endothelial and platelet activation.

RESULTS

All patients completed the exercise test. aPTT (P < 0.001) and factor VII (P = 0.01) significantly decreased while PT (P = 0.04), fibrinogen (P = 0.008), factor VIII (P < 0.001), platelet count (P = 0.002) and beta-TG levels (P = 0.01) significantly increased as a result of exercise. Compared to baseline there was an 11% increase in TAT (P = 0.04) and a 28% increase in PAP (P < 0.001) at peak exercise. One hour post exercise, there was a 43% increase in PAP whereas TAT levels became similar to those at baseline. Additionally vWf (P = 0.01) and sP-selectin (P = 0.02) levels significantly increased throughout the exercise protocol.

CONCLUSIONS

Patients with recently diagnosed and never treated mild to moderate essential hypertension undergoing submaximal aerobic exercise present evidence of enhanced fibrinolysis compared with a mild increase of coagulation indices. However, whether there is a favourable effect of exercise on fibrinolysis over coagulation and/or endothelial involvement during exercise needs to be further investigated.

Preanalytical conditions that affect coagulation testing, including hormonal status and therapy

Preanalytical conditions, be they due to the individual's physiologic state or to exogenous factors, can affect coagulation factors, in either a transient or a persistent manner, and need to be considered in laboratory testing. These conditions include physical and mental stress, diurnal variation, hormone levels and posture at the time of blood drawing. While testing of these factors has not been exhaustive and some results are conflicting, guidelines for testing conditions can be given.

A systematic review of the effects of acute psychological stress and physical activity on haemorheology, coagulation, fibrinolysis and platelet reactivity: Implications for the pathogenesis of acute coronary syndromes

Physical activity and psychological stress are two potential triggers for the onset of acute coronary syndromes (ACS). To examine the mechanisms underlying this association, we systematically reviewed the literature to determine the effects of acute psychological stress and physical activity on haemorheology and haemostasis. Studies examining the haemorheological and haemostatic response to an acute bout of physical activity (i.e. <60 min) or laboratory psychological stress task were eligible for inclusion. The experimental evidence, although compromised by various methodological weaknesses, suggests that low and moderate intensity physical activity may be cardio-protective through beneficial effects on fibrinolytic system. High levels of physical activity, and psychological to a lesser extent, have been consistently associated with robust changes in haemorheology and haemostasis. Such findings imply that such activities may have the potential to trigger the onset of ACS, although in reality this may be limited sedentary individual and/or those with pre-existing vascular disease. In addition, the data also suggest that individuals may be at a greatest risk of stress-induced thrombogenesis in the period immediately following physical activity or psychological stress, rather than during the activity per se. In conclusion, psychological stress and physical activity may act as potential triggers for the onset of ACS via effects on haemostasis and haemorheology.

Influence of physical fitness and smoking on the coagulation system in hypertensive patients: effect on prothrombin fragment F1+2

OBJECT

Recently, prothrombin fragment F1+2 was shown to be a sensitive direct marker of thrombin formation. We examined the effect of lifestyle (including physical activity) on prothrombin fragment F1+2 levels.

METHODS

Using the results of a questionnaire, the subjects were classified into groups on the basis of multiple medications, smoking, exercise, and drinking alcohol. The prothrombin fragment F1+2 levels were compared between each pair of groups and differences were analyzed using the unpaired t-test. Correlations between each parameter and the systolic and diastolic blood pressure, as well as with prothrombin fragment F1+2, were examined by multiple regression analysis. Patients The subjects were 109 patients who had essential hypertension without a past history of thrombotic events

RESULTS

Smokers (1.47 +/- 0.75 vs 0.98 +/- 0.46 nmol/L, p<0.0001), and those without regular exercise (1.22 +/- 0.59 vs 0.68 +/- 0.30 nmol/L, p<0.0001) had higher levels of prothrombin fragment F1+2. Age, lack of exercise, and smoking were significant predictors of a high concentration of prothrombin fragment F1+2. Of the smokers, the patient with a regular exercise had low F1+2 compared with those without regular exercise (0.75 +/- 0.20 vs 2.01 +/- 0.49 nmol/L, p<0.0001.

CONCLUSIONS

In patients with essential hypertension, age, smoking, and lack of regular exercise may increase the risk of thrombosis. Even in smokers, a regular exercise routine may reduce the tendency towards thrombus formation.

Hemostatic response to acute physical exercise in healthy adolescents

The chronic and immediate post-exercise responses in the hemostatic and fibrinolytic systems have been shown to be variable and reflect differing adaptations with ageing and responses to exercise protocols. This study investigated the effects of acute and exhaustive exercise on the amplitude and duration of hemostatic and fibrinolytic responses in young adolescent males. The sample comprised 10 sedentary boys (13.2+/-0.5 years, 55.8+/-11.3kg, 165.7+/-7.4cm), who had not exercised or received any medication for at least 2 weeks before the experiments. The subjects performed exhaustive stepping exercise, consisting of 1s up and down cycles to fatigue. When the subjects were unable to maintain the required stepping rhythm, they were given a 30s recovery period. Following each 30s recovery participants recommenced the stepping cadence until fatigue prevented them continuing. Venous blood samples were drawn before and immediately, 1 and 24h after exercise to assess the following coagulation and fibrinolytic parameters: Platelet counts, activated partial thromboplastin time (aPTT), prothrombin time (PT), coagulation factor VIII (FVIII:C), von Willebrand factor (vWF), fibrinogen concentration, thrombin-antithrombin complex (TAT), D-dimer, plasminogen activator inhibitor (PAI-1), and tissue-type plasminogen activator (t-PA). Immediately following exercise, platelet counts, aPTT, FVIII, vWF and t-PA were significantly elevated in contrast to PAI-1, which decreased significantly until 1h after exercise. FVIII and platelet counts were elevated at 1 and 24h after exercise, respectively. Only the parameters FVIII and PAI-1 did not return to baseline values during the first hour after physical exercise. When compared to adults the results revealed different rates and ranges of coagulation and fibrinolysis parameters being activated by exhaustive exercise in this group of adolescents.

Cross-laboratory audit of normal reference ranges and assessment of ABO blood group, gender and age on detected levels of plasma coagulation factors

We have assessed the influence of the ABO blood group, gender and age on plasma levels of the coagulation factors II, V, VII, VIII, IX, X, XI and XII as part of a quality audit of laboratory activities. There was no statistically significant difference in gender donor age (total normal donors: n = 406, mean/median age = 46.0/47.0 years, range = 16-77 years; females: n = 177, mean/median age = 44.7/46.0 years, range = 16-75 years; males: n = 229, mean/median age = 47.0/48.0 years, range = 17-77 years). With increasing age, we observed small but statistically significant rises (linear correlation; P < 0.01 for all parameters) in factors V, VII, VIII, IX and XI. With gender, we observed higher levels (P < 0.05) in females for factors II, VII, X, IX, XI and XII. With the ABO group, we observed lower levels in the O group (versus non-O group; P < 0.05) for factors VIII, IX and XII. We could therefore define differing normal reference ranges based on the differing study data. Study findings are compared with previously published literature, and this has identified a wide diversity in normal reference ranges both between different factors and between different studies. Finally, we also performed a cross-laboratory audit of peer laboratory practice and similarly show a wide diversity in normal reference ranges used between different laboratories.

Dynein-dynactin complex mediates protein kinase A-dependent clustering of Weibel-Palade bodies in endothelial cells

OBJECTIVE

Perinuclear clustering is observed for several different organelles and illustrates dynamic regulation of the secretory pathway and organelle distribution. Previously, we observed that a subset of Weibel-Palade bodies (WPBs), endothelial cell-specific storage organelles, undergo centralization when endothelial cells are stimulated with cAMP-raising agonists of von Willebrand factor (vWF) secretion. In this study, we investigated this phenomenon of WPB clustering in more detail.

METHODS AND RESULTS

Our results demonstrate that the clustered WPBs are localized at the microtubule organizing center and that cluster formation depends on an intact microtubule network. Disruption of the microtubules by nocodazole completely abolished clustering, whereas treatment with the actin depolymerizing compound cytochalasin B had no effect on WPB clustering. Interfering with the dynein-dynactin interaction by overexpression of the p50 dynamitin subunit or the CC1 domain of the p150glued subunit of the dynactin complex completely inhibited perinuclear clustering of WPBs, suggesting that dynein activity mediates this process. Furthermore, we found that inhibition of dephosphorylation resulted in an increase in clustering, whereas inhibition of protein kinase A (PKA) markedly reduced WPB clustering.

CONCLUSIONS

These results suggest that perinuclear clustering of WPBs involves PKA-dependent regulation of the dynein-dynactin complex. Endothelial cell stimulation with epinephrine results in retrograde movement of a subset of WPBs to the microtubule organizing center. This minus-end directed transport requires an intact microtubular network and is mediated by the motor protein dynein. Together, our results suggest that epinephrine-induced clustering of WPBs involves PKA-dependent regulation of the dynein-dynactin complex.

Exercise-induced changes in coagulation and fibrinolysis in healthy populations and patients with cardiovascular disease

This review highlights the clinical significance of coagulation and fibrinolytic responses, and adaptations in healthy individuals and patients with cardiovascular disease (CVD). Much of the review focuses on indicators of the potential for coagulation and fibrinolysis. The terms 'coagulation potential' and 'fibrinolytic potential' are used frequently, as much of the literature in the area of exercise haemostasis evaluates factors that reflect an increased potential for coagulation, while coagulation per se, may or may not be occurring. Similarly, fibrinolysis is definitively the lysis of inappropriate or excessive blood clot, which may or may not be occurring when the enzymes that stimulate fibrinolysis are activated. Nevertheless, markers of coagulation and fibrinolytic potential are associated with CVD, ischaemic events, and cardiovascular mortality. Additionally, fibrinolytic potential is associated with other established CVD risk factors. Ischaemic events triggered by physical exertion are more likely to occur due to an occlusive thrombus, suggesting the exercise-induced responses related to haemostasis are of clinical significance. The magnitude of increase in coagulation potential, platelet aggregation and fibrinolysis appears to be primarily determined by exercise intensity. Patients with CVD may also have a larger increase in coagulation potential during acute exercise than healthy individuals. Additionally, the magnitude of the fibrinolytic response is largely related to the resting fibrinolytic profile of the individual. In particular, high resting plasminogen activator inhibitor-1 may diminish the magnitude of tissue plasminogen activator response during acute exercise. Therefore, acute responses to exercise may increase the risk of ischaemic event. However, chronic aerobic exercise training may decrease coagulation potential and increase fibrinolytic potential in both healthy individuals and CVD patients. Due to the aforementioned importance of resting fibrinolysis on the fibrinolytic response to exercise, chronic aerobic exercise training may cause favourable adaptations that could contribute to decreased risk for ischaemic event, both at rest and during physical exertion.

Blood coagulation and fibrinolysis after extreme short-term exercise

INTRODUCTION

Maximal exercise may be a trigger for cardiovascular events. The aim of the study was to investigate changes in blood coagulation and fibrinolysis following maximal short-term exercises with different durations up to 90 s.

METHODS

A total of 15 healthy nonsmokers underwent three isokinetic maximal tests on an SRM cycle ergometry system with durations of 15, 45, and 90 s. Blood samples were taken after a 30-min rest, immediately before and after exercise, 15 min, and 1 h after completion of exercise. For the investigation of blood coagulation, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complex (TAT), intrinsic and extrinsic total (TTPin+ex), and endogenous thrombin potential (ETPin+ex) were measured. For testing fibrinolysis, determinations of plasmin-alpha(2)-antiplasmin complex (PAP), tissue-type plasminogen activator (tPA)-antigen, plasminogen activator inhibitor (PAI)-1-antigen and D-dimer were used.

RESULTS

Immediately after the exercise tests, only F1+2 (15- and 90-s test) and TTPin (45 and 90 s) showed a moderate increase (p<0.05), while TAT and ETP was unchanged. In contrast, a clear increase in PAP and tPA-antigen already after 15 s maximal exercise in relation to the exercise duration time could be investigated. These effects were not totally reversed to baseline 15 min after exercise; D-dimer and PAI-1-antigen still remained unchanged after these types of exercise.

CONCLUSIONS

Maximal short-term exercise does not lead to a relevant activation of blood coagulation in healthy young subjects, it is only slightly altered within the normal range. In contrast, fibrinolysis is clearly activated, and the increase is directly dependent on exercise duration. Additionally, it could be shown for the first time that fibrinolysis is already activated after 15 s maximal exercise duration.

Strenuous but not moderate exercise increases the thrombotic tendency in healthy sedentary male volunteers

We have investigated the effect of moderate and strenuous exercise on experimental arterial thrombus formation in men. Thrombogenesis was measured in 15 sedentary healthy male volunteers at rest or immediately after two standardized exercise tests performed for 30 min on a bicycle ergometer. The exercises were performed at a constant load corresponding to either 50 or 70% maximal oxygen uptake. Thrombus formation was induced ex vivo by exposing a collagen-coated coverslip in a parallel plate perfusion chamber to native nonanticoagulated blood for 3 min. The shear rate at the collagen surface was 2,600 s(-1). Platelet and fibrin deposition was quantified by immunoenzymatic methods. The results show that moderate exercise did not affect arterial thrombus formation. In contrast, platelet thrombus formation on collagen was increased on the average by 20% after 30 min at 70% maximal oxygen uptake (P = 0.03). Fibrin deposition on collagen remained unchanged with exercise, regardless of its intensity. Thus, with the use of a clinically relevant human experimental model of thrombosis, the present study suggests that exercise of heavy intensity may increase the risk for arterial thrombogenesis in sedentary young healthy male volunteers.

Tissue factor-dependent pathway is not involved in exercise-induced formation of thrombin and fibrin

In healthy individuals, prolonged intensive physical exercise leads to an activation of blood coagulation that results in the formation of thrombin and fibrin. This study investigated whether oxidative stress during intensive physical exercise induces tissue factor (TF) via activation of the redox-responsive transcription factor nuclear factor-kappaB (NF-kappaB). Twelve young men performed a standardized 1-h maximal run on a treadmill that gave rise to significant increases of markers of thrombin and fibrin formation. The ratio of intracellular reduced to oxidized glutathione as measured by HPLC decreased from 23.3 +/- 10.7 to 14.2 +/- 6.5 (P < 0.05), indicating the generation of free radicals during exercise. Electrophoretic mobility shift assays from nuclear extracts of peripheral blood mononuclear cells revealed that exercise testing increased NF-kappaB (p50/p65) binding activity to a NF-kappaB consensus sequence by 105 +/- 68% (P < 0.01) but did not affect NF-kappaB (p65/c-Rel) binding to a nonconsensus-kappaB-like site present in the TF promoter. Consistently, there was no exercise-induced increase in TF expression as demonstrated by TF-specific immunofluorescence staining and ELISA. Thus selective activation of NF-kappaB (p50/p65) during intensive physical exercise does not result in the expression of TF, suggesting that the TF-dependent pathway in peripheral blood mononuclear cells does not account for exercise-induced formation of thrombin and fibrin.

Effects of acute exercise on hemorheological, endothelial, and platelet markers in patients with chronic heart failure in sinus rhythm

BACKGROUND

Chronic heart failure (CHF) is associated with an increased risk of thrombosis and thromboembolic events, including stroke and venous thromboembolism. which may be related to a prothrombotic or hypercoagulable state. Acute vigorous exercise has been associated with activation of hemostasis, and this risk may well be particularly increased in patients with CHF.

HYPOTHESIS

The study was undertaken to determine whether acute exercise would adversely affect abnormalities of hemorheological (fibrinogen, plasma viscosity, hematocrit), endothelial (von Willebrand factor), and platelet markers (soluble P selectin) in patients with CHF.

METHODS

We studied 22 ambulant outpatients (17 men; mean age 65+/-9 years) with stable CHF (New York Heart Association class II-III and a left ventricular ejection fraction of < or =40%) who were exercised to exhaustion on a treadmill. Results were compared with 20 hospital controls (patients with vascular disease, but free of CHF) and 20 healthy controls.

RESULTS

Baseline von Willebrand factor (p = 0.01) and soluble P-selectin (p = 0.006) levels were significantly elevated in patients with CHF when compared with controls. In the patients with CHF who were exercised, plasma viscosity, fibrinogen, and hematocrit levels increased significantly, both immediately post exercise and at 20 min into the recovery period (repeated measures analysis of variance, all p<0.05). There was a positive correlation between exercise workload and the maximal changes in plasma viscosity in the patients with CHF (Spearman r = 0.5, p = 0.02). Plasma viscosity levels increased with exercise in the hospital control group, although no other exercise-induced changes were noted in this group.

CONCLUSION

The present study indicates that the hemorheological indices. fibrinogen, and hematocrit specifically increase during acute exercise in patients with CHF. Although moderate exercise should be encouraged in patients with CHF, vigorous exercise should probably be avoided in view of its potential prothrombotic effects in this high-risk group of patients.

Clotting and fibrinolytic activity change during the 1 h after a submaximal run

PURPOSE

To determine the changes in clotting and fibrinolytic activity during the 1-h period after an acute submaximal exercise at a specific relative exercise intensity to ascertain whether during this time there is a greater risk for developing a clot formation or thrombus.

METHODS

Ten healthy men reported between 0700 and 1000 h and ran at 70-75% VO2max or walked at 1.2 mph for 30 min in a random counter-balanced order. Venous blood was obtained at rest, immediately after, and every 20 min during the 1-h recovery.

RESULTS

There were no differences in the resting parameters for each treatment. Walking did not alter the activity of any of the measures analyzed compared with rest. Clotting indicators activated partial thromboplastin time (APTT) was significantly decreased by approximately 2 s and remained at this level during the 1-h recovery, and factor VIII activity was elevated 66% immediately after the run and remained elevated at this level during the 1-h recovery period. Fibrinolytic indicators, t-PA, and D-dimers were significantly increased immediately after the run. However, t-PA demonstrated a quadratic negative slope during the 1-h recovery time. D-dimers remained elevated during the 1-h recovery time.

CONCLUSIONS

These results suggest that running at 70-75% VO2max resulted in elevated clotting and fibrinolytic activity. However, the clotting activity was sustained during a time when fibrinolytic activity declined, which suggests a more favorable situation for clot formation during this time after exercise.

Effect of acute exercise on the raised plasma fibrinogen, soluble P-selectin and von Willebrand factor levels in chronic atrial fibrillation

BACKGROUND

There is increasing evidence that chronic atrial fibrillation (AF) is associated with a prothrombotic or hypercoagulable state.

HYPOTHESIS

This study was undertaken to determine whether short-term exercise in patients with chronic AF would shift the overall hemostatic balance toward a more prothrombotic state with a reduction in fibrinolytic potential.

METHODS

We recruited 20 patients (13 men; mean age 65 years +/- 11 standard deviation [SD]) with chronic AF who were not treated with antithrombotic therapy and exercised them to exhaustion using a multistage treadmill exercise (standard Bruce) protocol. Blood samples were taken pre exercise, immediately after cessation of exercise, and at 20 min post exercise. The prothrombotic state was quantified by fibrinogen (an index of hemorheology and a coagulation factor), soluble P-selectin (sP-sel, marking platelet activation), von Willebrand factor (vWF, an index of endothelial dysfunction), and plasminogen activator inhibitor-1 (PAI-1, a regulator of fibrinolytic activity) levels. There were two groups of age- and gender-matched controls in sinus rhythm: (1) healthy controls, and (2) "hospital controls" who were patients with vascular disease.

RESULTS

Baseline levels of vWf (p = 0.034) and fibrinogen (p < 0.0001), but not sP-sel (p = 0.075) were significantly elevated in patients with AF compared with both control groups in sinus rhythm. The PAI-1 levels were highest in the hospital control patients, but not in chronic AF (p = 0.041). Following treadmill exercise, achieving a mean metabolic equivalent of 4.9 METS (+/- 1.75 SD) and total exercise duration of 4.9 min (+/- 2 SD), there was a significant rise in plasma fibrinogen (repeated measures analysis of variance [ANOVA] p = 0.047) and a reduction in PAI-1 levels (p = 0.025) in patients with AF. There were no significant changes seen in vWf (p = 0.308) or sP-sel (p = 0.071) levels. No significant changes in these indices were seen in hospital controls (all p = not significant), despite a much longer duration of exercise with greater workload.

CONCLUSION

Patients with chronic AF have increased vWf and fibrinogen levels compared with sinus rhythm. Exercise to exhaustion influences the hypercoagulable state in chronic AF, with a rise in plasma fibrinogen and possible increase in fibrinolytic activity. Nevertheless, acute exercise does not appear to have a significant influence on endothelial dysfunction or platelet activation in patients with AF.

Aging, physical conditioning, and exercise-induced changes in hemostatic factors and reaction products

The influence of age on training-induced changes in resting and stimulated hemostatic potential was studied in three age categories (Cat I-III; 20-30 yr, 35-45 yr, and 50-60 yr, respectively) of sedentary men before and after 12 wk of training. Coagulation, fibrinolytic activity, and activation markers (reflecting fibrin formation and degradation) were determined. Physical conditioning resulted in a more pronounced increase in von Willebrand factor (vWF) and factor VIII clotting activity (FVIII:c) in Cat I and II and a more pronounced shortening of the activated partial thromboplastin time in all categories at maximal exertion and during recovery. Enhanced increases in tissue-type plasminogen activator (t-PA) antigen and activity and single-chain (sc) urokinase-type plasminogen activator (u-PA) at maximal exercise and 5 min of recovery were observed in all age groups after training. The effects on FVIII:c, vWF, and scu-PA were most pronounced in the youngest age group (Cat I). Increases in the marker of thrombin generation were highest in Cat III; no effect was seen on thrombin-antithrombin complex, plasmin-antiplasmin complex, and D-dimer in any of the age groups. We concluded that training enhances both coagulation and fibrinolytic potential during strenuous exercise. The effect on FVIII/vWF and t-PA/u-PA is most pronounced in younger individuals, whereas thrombin formation is most pronounced in older individuals.

Exercise induces a change in plasma fibrinogen concentration: fact or fiction?

This study examined the effect of exercise on plasma fibrinogen concentrations with simultaneous measurements of plasma volume changes. Eight moderately active males aged 26.6+/-3.6 years (mean +/- SD) completed maximal (VO2max) and submaximal (75% VO2max for 30 minutes) exercise trials separated by 7 days. Venous blood samples were obtained at rest, immediately postexercise, and following 30 minutes of recovery. Whole blood was analysed for haematocrit and haemoglobin, while citrated plasma was assayed for fibrinogen levels. Values of haematocrit and haemoglobin before and after exercise were utilised for the estimation of plasma volume changes. Plasma volume decreased (p<0.05) immediately following both maximal (-17.7+/-5.1%) and submaximal (-14.3+/-4.1%) exercise. Exercise resulted in decreased plasma fibrinogen levels (maximal exercise: from 266.3+/-14.5 to 222.2+/-23.9 mg x dL(-1); submaximal exercise: from 239.5+/-45.4 to 209.7+/-42.4 mg x dL(-1)) only when postexercise raw data were corrected for the contraction of plasma volume. It is concluded therefore that changes in plasma volume in response to exercise should be taken into account when interpreting exercise effects on plasma fibrinogen concentration.

Endogenous plasminogen activator expression after embolic focal cerebral ischemia in mice

Urokinase-type plasminogen activator (u-PA) and tissue-type plasminogen activator (t-PA) play important roles in fibrinolysis, cell migration, tissue destruction, angiogenesis and tissue remodeling. u-PA and t-PA activity in tissue are tightly regulated by plasminogen activator inhibitor-1 (PAI-1). However, little is known of the activity of endogenous plasminogen activators (PAs) and PAI-1 in ischemic brain. To evaluate whether cerebral ischemic injury induces endogenous PAs and PAI-1, we measured PA activity from brain homogenates, and examined the expression of t-PA mRNA, u-PA mRNA and PAI-1 mRNA from brain homogenates in C57BL/6J mice (n=45) weighing 29-35 g in which the middle cerebral artery (MCA) was occluded by a fibrin-rich clot. Brain homogenates were prepared for direct casein zymography from control non-ischemic mice (n=4) and mice at 2 h (n=5), 4 h (n=5), and 24 h (n=4) after MCA occlusion (MCAO). Also, u-PA and t-PA knockout mice at 4 h (n=2, each) after MCAO were used as a negative control for direct casein zymography. Frozen sections for in situ zymography were obtained from control mice (n=2) and mice at 2 h, 4 h, and 24 h (n=2, per time point) after clot occlusion. Brain homogenates were prepared for reverse transcriptase-polymerase chain reaction (RT-PCR) to examine t-PA mRNA, u-PA mRNA and PAI-1 mRNA expression from control non-ischemic mice (n=4) and mice at 2 h (n=5), 4 h (n=5), and 24 h (n=5) after MCAO. By direct casein zymography, u-PA activity increased at 4 h (P<0.05), and 24 h (P<0.05) after stroke in the ischemic hemisphere compared with the non-ischemic mice. Activity of t-PA in ischemic brain was not significantly different from the control group. As measured by in situ zymography, PA activity, most likely u-PA, was present in the ischemic hemisphere. By RT-PCR, expression of PAI-1 mRNA, but not u-PA mRNA and t-PA mRNA, increased 3-, 15- and 25-folds in the ischemic hemisphere at 2 h, 4 h and 24 h after stroke, respectively, compared with control mice. This study demonstrates that PAI-1 mRNA and u-PA activity increase in mouse brain after stroke.

von Willebrand Factor Propeptide in Vascular Disorders: A Tool to Distinguish Between Acute and Chronic Endothelial Cell Perturbation

Before de novo synthesized von Willebrand factor (vWF) leaves the endothelial cell, it undergoes endoproteolytic cleavage of its propeptide (vW antigen II). The processed vWF and propeptide are either released constitutively or, following activation of the endothelium, released through the regulated pathway. In a recent study (Borchiellini et al, Blood 88:2951, 1996), we showed that the half-life of mature vWF and of its propeptide differ fourfold to fivefold. We postulated that the molar ratio of the propeptide to mature vWF could serve as a tool to assess the extent of endothelial cell activation under physiologic and clinical conditions. To test this hypothesis, we measured mature vWF and propeptide in patients with documented acute and chronic vascular disease, including patients with thrombotic thrombocytopenic purpura (TTP), acute septicemia, and diabetes mellitus. These data were compared with experimental conditions in healthy subjects in which perturbation of the endothelium was simulated by physical exercise or by administration of 1-deamino-8-D-arginine vasopressin (DDAVP) or endotoxin. In all individuals of the latter study group, both vWF and propeptide levels were elevated during the acute phase of the experimentally induced vascular perturbation; at later time points after stimulation, only vWF levels remained elevated. In patients with sepsis and TTP, both vWF and propeptide were elevated several-fold. Thus, this pattern can readily be explained in terms of acute perturbation of the endothelium. In contrast, in patients with diabetes mellitus propeptide levels were only slightly elevated, whereas vWF levels were elevated twofold to threefold. This pattern is a typical feature of chronic, low-grade activation of the endothelium. These observations support our hypothesis that measurement of both propeptide and vWF levels allows to discriminate between chronic and acute phases of endothelial cell activation in vivo. Measurement of only vWF is less indicative in this respect.

The effect of age on expression of endogenous plasminogen activators after focal cerebral ischemia in mice

We measured urokinase-type plasminogen activator (u-PA) and tissue-type plasminogen activator (t-PA) activity in the brain of 2-3 month old and 6-8 month old mice subjected to 4 h of middle cerebral artery (MCA) occlusion. t-PA activity was present in all non-ischemic and ischemic young mouse brain. In contrast, t-PA activity was present in 46.7% of non-ischemic middle aged mouse brain and in 44.4% of ischemic middle aged mouse brain. u-PA activity was present in all young and middle aged non-ischemic brains.

Effect of anticoagulant therapy on the hypercoagulable state in patients carrying the factor V Arg506Gln mutation

Resistance to activated protein C, caused by a single point mutation in the factor V gene (Arg506Gln or FV Leiden), is the most prevalent single risk factor associated with venous thromboembolic disease. The aim of this study was to investigate the effectiveness of standard oral anticoagulant therapy (OAT) in patients with the Arg506Gln mutation compared with a matched control group. The study compared selected variables in 27 patients carrying the Arg506Gln mutation with 27 sex- and age-matched controls in steady state oral anticoagulant treatment (OAT). The study showed that similar doses of vitamin K antagonists in carriers and noncarriers suppress and generate a uniform distribution of coagulation markers in steady state OAT. Thus, it seems that OAT with standard treatment doses is just as effective in patients with the Arg506Gln mutation as in comparable controls without the mutation.

Activation of coagulation and fibrinolysis after rehabilitative exercise in patients with coronary artery disease

It has been suggested that blood coagulation be activated and fibrinolytic activity be impaired in patients with coronary artery disease (CAD). With regard to the activation of coagulation and fibrinolysis occurring during exercise in healthy individuals, we examined the hypothesis that rehabilitative exercise in patients with CAD might give rise to an exaggerated activation of coagulation. In 12 patients with angiographically documented CAD without myocardial infarction within the preceding 6 months (male, age 55+/-9 years [SD]) and in 12 healthy controls (male, 52+/-7 years), molecular markers of thrombin, fibrin, and plasmin formation were determined before and after a rehabilitative group exercise session lasting 1 hour. Resting levels of prothrombin fragment 1+2 were lower in patients with CAD (0.67+/-0.2 [SE] vs 1.04+/-0.2 nmol/L, p <0.001) and remained unchanged after exercise, whereas a significant increase was noted in controls (p <0.01). After exercise, plasma levels of thrombin-antithrombin III complexes and of fibrinopeptide A increased significantly in both groups, although there were more pronounced changes in controls. Exercise resulted in a marked generation of plasmin as indicated by plasmin-alpha2-antiplasmin complexes increasing 2.5-fold in patients (p <0.001) and threefold in controls (p <0.001). Repeated experiments in control subjects after administration of aspirin (day 1: 500 mg; days 2 to 5: 100 mg) documented that differences between groups could not be attributed to aspirin medication (100 mg/day) in patients with CAD. We concluded that rehabilitative exercise in patients with CAD beyond the immediate postinfarction period has no detrimental effects on thrombin, fibrin, and plasmin formation.

Physical exertion induces thrombin formation and fibrin degradation in patients with peripheral atherosclerosis

Sudden extreme physical stress is associated with an increased risk of myocardial infarction mainly in people with preexisting atherosclerosis. In this study we compared the effect of submaximal exercise on coagulation and fibrinolysis in patients with peripheral arterial occlusive disease (PAOD) with that in healthy control subjects. Fifteen PAOD) patients with intermittent claudication and 15 healthy control subjects, matched for age, sex, medication use, smoking habit, and conditioning, were studied. Thrombin-antithrombin III complex (TAT), D-dimer, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI)-1 antigens (Ag), t-PA activity, and plasmin-alpha2-antiplasmin complex (PAP), as well as plasma catecholamines, were measured before and after a treadmill exercise test. At rest, fibrinogen (3.3+/-0.5 versus 2.9+/-0.5 g/L [mean+/-SD]; P<.05), D-dimer (392+/-128 versus 271+/-113 ng/mL; P<.05), t-PA Ag (9.1+/-5.1 versus 5.5+/-1.2 ng/mL; P<.02), and PAI-1 Ag (14.9+/-7.1 versus 7.6+/-3.8 ng/mL; P<.002) levels in plasma were markedly higher in the patient group than in the control group. In patients but not in control subjects, exercise of similar intensity elevated circulating concentrations of TAT (from 3.43+/-1.45 to 4.83+/-2.27 ng/mL; P<.05). Exercise caused a parallel increase in D-dimer, t-PA Ag, t-PA activity, PAP, and catecholamines in both groups, whereas PAI-1 Ag remained stable. Plasma lactic acid was significantly higher in patients after exercise and was associated with lower-limb ischemia. Compared with healthy control subjects, patients with PAOD showed higher t-PA Ag, PAI-1 Ag, and D-dimer levels both at rest and after exercise. Notably, submaximal exercise on a treadmill enhanced thrombin formation in patients with PAOD but not in the control subjects. Sudden catecholamine release and local ischemia during exercise may accelerate the preexisting prothrombotic potential of the atherosclerotic vessel wall.

Earthquake-induced potentiation of acute risk factors in hypertensive elderly patients: possible triggering of cardiovascular events after a major earthquake

OBJECTIVES

We sought to investigate the potentiation of acute risk factors after the Hanshin-Awaji earthquake (7.2 on the Richter scale).

BACKGROUND

The frequency of cardiovascular events increases just after a major earthquake, but the causative factors have not been fully investigated.

METHODS

We studied the changes in cardiovascular risk factors in 42 elderly outpatients with well-controlled hypertension living near the epicenter (Awaji-Hokudan districts) 7 to 14 days after the earthquake when the major felt-aftershocks persisted. They all experienced the highest stress grading of 6 (catastrophic stress) according to the DSM-III-R. To study the hemostatic profile and endothelial cell state, we measured the blood pressure (BP), hematocrit and lipid profiles as well as fibrinogen, a marker of fibrin turnover (D-dimer), fibrinolytic factors (plasmin-alpha2-plasmin inhibitor complex [PIC], tissue-type plasminogen activator [t-PA] antigen and t-PA inhibitor [PAI] activity) and an endothelial cell-derived marker (von Willebrand factor [vWF]).

RESULTS

Systolic and diastolic blood pressures and other variables increased after the earthquake. Before and after the earthquake, the median (25th to 75th percentiles) systolic BP was 152 (range 142 to 164) and 170 mm Hg (range 161 to 178), respectively (p < 0.0001), and the diastolic BP was 83 (range 79 to 88) and 91 mm Hg (range 84 to 96), respectively (p < 0.0001). Of blood viscosity determinants, hematocrit was 38.1% (range 40.7% to 35.9%) and 39.7% (range 42.9% to 38.3%), respectively (p < 0.001), and fibrinogen 316 (range 272 to 360) and 335 mg/dl (range 307 to 391), respectively (p < 0.05). Von Willebrand factor was 128% (range 74% to 148%) and 148% (range 100% to 178%), respectively (p < 0.01); D-dimer was 410 (range 285 to 633) and 560 ng/ml (range 391 to 888), respectively (p < 0.0001); and PIC was 0.74 (range 0.58 to 0.91) and 0.75 microg/ml (range 0.58 to 1.1), respectively (p < 0.05). In contrast, lipid profiles did not change after the quake. When the patients were classified into the high stress and moderate stress groups according to the degrees of damage to their house and injury to family members, the levels of fibrinogen, vWF, PIC and t-PA antigen were increased only in the former group, whereas BP, hematocrit and D-dimer levels were increased in both groups. These abnormalities of acute risk factors, except for vWF, were transient and decreased to prequake levels by 4 to 6 months after the quake.

CONCLUSIONS

Earthquake-induced stress seems to induce transient increases in BP, blood viscosity determinants and fibrin turnover and to prolong endothelial cell stimulation. The potentiation of these acute risk factors might contribute to the occurrence of cardiovascular events just after a major earthquake in elderly subjects with hypertension.