Activation of the coagulation system in women with mitral stenosis and sinus rhythm

Coagulation, Fibrinolytic System Activation and Endothelial Dysfunction in Patients With Mitral Stenosis and Sinus Rhythm

Anticoagulation treatment can prevent systemic embolism in patients with mitral stenosis (MS) and atrial fibrillation (AF), but this treatment is under debate if patients are in sinus rhythm. The authors aimed to determine the hemostatic changes in patients with MS and sinus rhythm. Forty-six patients (28 in sinus rhythm and 18 in AF) with mitral stenosis were enrolled in this study. They studied systemic venous fibrinogen, D-dimer, antithrombin-III, tissue plasminogen activator (tPA), plasminogen activator inhibitor-I (PAI-I), von Willebrand factor (vWF), and platelet factor 4 (PF 4) in these patients. The patients were first classified according to their rhythm as sinusal and AF, and then according to the presence of left atrial spontaneous echo contrast (LASEC). Fibrinogen, D-dimer, antithrombin-III, vWF, and PF 4 levels were significantly greater in patients with MS and sinus rhythm or atrial fibrillation compared to the control group (p<0.05). Whether the rhythm was sinus or AF, fibrinogen, D-dimer, antithrombin-III, vWF, and PF 4 levels were significantly higher in patients with LASEC than in the control group (p<0.05). Only PF 4 was higher in the AF group than in those with sinus rhythm (p<0.05). As to plasminogen activator and PAI-I levels, only tissue plasminogen activator levels were found to be higher in the AF group than in those with sinus rhythm and the control group (p<0.05). In patients with mitral stenosis and sinus rhythm, if LASEC is present, coagulation activation, platelet activation, and endothelial dysfunction are similar in patients with AF, and anticoagulation should be considered in these patients.

Coagulation activity is increased in the left atria of patients with paroxysmal atrial fibrillation during the non-paroxysmal period. Comparison with chronic atrial fibrillation

BACKGROUND

Evaluation of plasma markers of thrombin activity (thrombin-antithrombin III complex: TAT), active fibrinolysis (plasmin-alpha 2-plasmin inhibitor complex: PIC), and platelet activity (platelet factor 4: PF4) is useful for identifying patients with various cardiovascular disorders who are at high risk of thromboembolism. In this study, these markers were investigated in the left atria (LA) of patients with paroxysmal atrial fibrillation (pAF) in the non-paroxysmal period.

METHODS AND RESULTS

Patients with pAF (n=10) and chronic AF (cAF) (n=10) were enrolled. TAT, PIC, and PF4 levels were determined in blood samples obtained from the LA of AF patients before radiofrequency catheter ablation. TAT levels were high in both pAF and cAF patients. PF4 levels were slightly elevated in both groups, but there was no significant difference between the groups. On the other hand, PIC levels in both groups were almost within normal limits, again with no significant difference between groups.

CONCLUSIONS

Coagulation activity is elevated in the LA of patients with pAF, even in the non-paroxysmal period, so these patients are at high risk of thromboembolism and anticoagulant therapy is indicated.

Biochemical markers of coagulation activation in mitral stenosis, atrial fibrillation, and cardiomyopathy

Advances in the understanding of the biochemistry of the mechanism of hemostasis have led to the development of sensitive methods for determining levels of markers which reflect thrombin activity (thrombin-antithrombin III complex, fibrinopeptide A, F1 + 2 fragment), active fibrinolysis (D-dimer, plasmin-alpha 2-plasmin inhibitor complex), and platelet activity (platelet factor 4, beta-thromboglobulin) in vivo. Measurement of these markers may be useful in identifying patients with various cardiovascular disorders at high risk of thromboembolism.

The platelet of the patients with ischemic cardiopathy and cardiac valve disease showed a reduction of 8OH-DPAT binding sites

Depression is prospectively associated with increased risk of coronary artery disease in individuals initially free of clinical cardiovascular disease probably by an increased platelet activity. The serotonergic receptors mainly implied in depression are 5-HT1A and 5-HT2 receptors. Activation of 5HT2 receptor induces platelet aggregation. Drugs with 5-HT1A receptor agonist and 5-HT2A receptor antagonist effects reduced the receptor-mediated platelet aggregation. There are only indirect data about 5-HT1A receptors presence in platelet membranes, thus our aims were to study the characteristics of the platelet membranes 5-HT1A binding sites of both healthy volunteers and patients with cardiac valve disease and ischemic cardiopathy. The bound of the 5-HT1A selective agonist 3H-8OH-DPAT to the platelet membranes 5-HT1A binding sites of patients with cardiac valve disease and ischemic cardiopathy were compared with a control group of healthy voluntaries using radioligand binding methods. The patients with cardiovascular disease showed a reduction (-50.40%) (p<0.01) of the 3H-8OH-DPAT bound to the platelet membranes 5-HT1A receptors (1.652+/-0.79 fmol/mg protein) with respect to the control group (3.331+/-0.16 fmol/mg protein). 3H-8OH-DPAT binding to human platelet membranes is saturable, of high affinity, and seems selective for 5-HT1A receptors, and similar to that described in animal brain and in other human cells. Patients with ischemic cardiopathy and cardiac valve disease showed a reduction of the 8OH-DPAT bound to the platelet membranes. Taken together, these findings suggest that the 8OH-DPAT bound to the human platelet membranes is modulated by modifications produced by cardiovascular disease conditions.

Plasma level of soluble P-selectin in patients with rheumatic mitral stenosis and sinus rhythm undergoing percutaneous mitral balloon valvuloplasty

OBJECTIVE

To determine whether plasma level of soluble P-selectin (sP-selectin) increases in rheumatic mitral stenosis (MS) patients with sinus rhythm, who have scheduled for percutaneous mitral balloon valvuloplasty (PMBV), and to examine the effect of PMBV on sP-selectin level.

METHODS

Twenty-six patients with MS and sinus rhythm (study group, 20 female, mean age 33 +/- 8 years) and a well-matched control group composed of 21 healthy volunteers (15 female, mean age 35 +/- 6 years) were enrolled in the study. In each patient left atrial (LA) thrombus was excluded by transesophageal echocardiography. sP-selectin levels were compared between study patients and controls, and between peripheral and LA blood. Changes in sP-selectin level 24 h and 4 weeks after PMBV were also analyzed.

RESULTS

A significantly higher basal sP-selectin level was noted in study group. After PMBV, the mitral valve area (MVA) increased and the transmitral mean gradient decreased significantly. At 24th hour after PMBV, sP-selectin level decreased from 1080.38 +/- 143.87 ng/ml to 960.00 +/- 103.26 ng/ml (p < 0.0001) and at 4th-week follow-up it was decreased from 960.00 +/- 103.26 ng/ml to 879.61 +/- 98.16 ng/ml (p < 0.0001). No significant difference was found between peripheral and LA blood regarding the sP-selectin level. Correlation analysis between the difference in MVA measured 24-hour after and before PMBV and the difference in sP-selectin level measured 24-hour after and before PMBV showed a significant direct relationship between these variables.

CONCLUSION

This study suggests that in patients with MS and sinus rhythm sP-selectin level increases probably due to turbulent flow across the stenotic valve. After PMBV sP-selectin shows a progessive decline, which is directly correlated with the increase in MVA.

Mechanism of reducing platelet activity by percutaneous transluminal mitral valvuloplasty in patients with rheumatic mitral stenosis

BACKGROUND

Previous studies have demonstrated that platelet activity significantly decreased after optimal percutaneous transluminal mitral valvuloplasty (PTMV) in patients with rheumatic mitral stenosis (MS). However, the mechanism of reducing platelet activity by valvuloplasty remains unclear.

METHODS AND RESULTS

We studied 19 patients with symptomatic MS who were undergoing PTMV. The fractions of unstimulated platelets expressing P-selectin in the venous blood obtained before, and at the 1-week and 4-week follow-ups after PTMV were determined by flow cytometry. The mitral valve areas, measured before and at the 1-week follow-up after PTMV, were calculated by means of the Doppler pressure half-time method. The mean (+/- SD) area of the mitral valve increased significantly after PTMV (1.05 +/- 0.17 vs 1.44 +/- 0.27 cm2, respectively; p < 0.0001). The mean left atrial area was reduced in size significantly after PTMV (36.6 +/- 11.4 vs 33.9 +/- 13.4 cm2, respectively; p < 0.05). The mean left atrial pressure (23.3 +/- 5.1 vs 18.0 +/- 5.8 mm Hg, respectively; p < 0.0001) and the mean pulmonary arterial pressure (31.4 +/- 7.8 vs 26.1 +/- 7.7 mm Hg, respectively; p < 0.0001) fell significantly after PTMV. The fraction of platelets expressing P-selectin in the venous blood fell significantly after PTMV (before PTMV, 4.7 +/- 2.4%; 1 week after PTMV, 2.2 +/- 2.1%; 4 weeks after PTMV, 2.0 +/- 1.7%; p < 0.0001). Correlation analysis demonstrated that there was a significantly direct relationship between the magnitude of increase in mitral valve area and the magnitude of decrease in the fraction of platelets expressing P-selectin in the venous blood 4 weeks after PTMV (p = 0.0013; r = 0.682). However, there was no significant correlation between the magnitude of decrease in the fraction of platelets expressing P-selectin in the venous blood and the magnitude of decrease in the left atrial area, the decrease in left atrial pressure, or the decrease in the pulmonary artery pressure after PTMV.

CONCLUSIONS

In patients with moderate-to-severe MS, increased platelet activation fell significantly after PTMV. It was the increase in mitral valve area by PTMV, instead of hemodynamic and echocardiographic factors, that accounted for the decrease in the fraction of venous platelets expressing P-selectin after PTMV.

Decreased platelet activation and endothelial dysfunction after percutaneous mitral balloon valvuloplasty

OBJECTIVE

This study was conducted to assess the changes in platelet activation and endothelial dysfunction in patients with mitral stenosis (MS) and sinus rhythm (SR) following percutaneous mitral balloon valvuloplasty (PMBV).

BACKGROUND

Systemic thromboembolism is a serious complication in patients with valvular heart disease, and its incidence is highest in those with mitral stenosis. A hypercoagulable state has also been reported in patients with mitral stenosis and sinus rhythm. A recent study has shown that patients with previous PMBV had a lower incidence of thromboembolism.

METHODS AND RESULTS

The study was conducted in 21 patients (two men, 19 women, mean age=34+/-6 years) with mitral stenosis and sinus rhythm (SR) who underwent percutaneous mitral balloon valvuloplasty and 17 healthy control subjects (two men, 15 women, mean age=33+/-6 years). Biochemical markers of platelet activity (beta thromboglobulin, BTG, and soluble P-selectin, sPsel) and endothelial dysfunction (von Willebrand Factor, vWF) were measured in both control subjects' and patients' serum samples taken immediately before PMBV and 24 h after PMBV procedure. All patients underwent successful PMBV. Significant improvement of mitral valve area, pulmonary artery pressure, mean mitral gradients, and left atrial diameter were achieved in all patients after PMBV. Compared with control subjects, patients with MS had higher plasma levels of BTG (66+/-26 ng/ml vs. 14+/-6 ng/ml, P<0.001), vWF (177+/-67 units/dl vs. 99+/-37 units/dl, P<0.0001), sPsel (226+/-74 ng/ml vs. 155+/-66 ng/ml, P<0.001). There was a significant reduction of plasma levels of BTG (66+/-26 ng/ml vs. 48+/-20 ng/ml, P=0.002), vWF (177+/-67 units/dl vs. 134+/-60 units/dl, P=0.001) and P-selectin (226+/-74 ng/ml vs. 173+/-71 ng/ml, P=0.008,) 24 h after PMBV.

CONCLUSION

We have shown that patients with severe MS and SR have increased platelet activation and endothelial dysfunction compared with control subjects and PMBV results in decreased platelet activity and improvement of endothelial injury.

Regional Left Atrial Coagulation and Fibrinolytic Activities in Patients With Mitral Stenosis

Systemic thromboembolism is a major complication of mitral stenosis (MS), especially in those patients having atrial fibrillation (AF). Recent evidence has suggested that regional left atrial coagulation activity may be increased in MS and may contribute to the pathophysiology of left atrial thrombus. However, the relation of left atrial coagulation activity to factors that predispose to left atrial thrombus formation is unknown. Also, the relations between left atrial and systemic coagulation activity, fibrinolysis, and platelet activation remain unresolved. Left atrial and peripheral venous levels of fibrinogen, antithrombin III, factor VII and factor VIII for coagulation, D-dimer, tPA and PAI-I, plasmin and antiplasmin for fibrinolysis, and platelet factor 4 and vWF for platelet activation, and endothelial dysfunction were measured in 46 patients with MS and normal clotting times who were undergoing percutaneous mitral valvuloplasty. Left atrial tPA, plasmin, PAI-I, antiplasmin, PF4, and vWF levels exceeded the corresponding peripheral venous levels (P < 0.05) in patients with MS, being more significant in the AF subgroup. There were no significant differences between left atrial and peripheral venous levels of fibrinogen, D-dimer, factor VII, and factor VIII within the patient group (P > 0.05). The results suggest that there are significant variations in the indices of coagulation, fibrinolytic system and platelet activation, and endothelial dysfunction between left atrial and peripheral venous blood samples of patients with MS that may be due to limited spillover from the left atrium to the systemic circulation.

Left atrial platelet activity with rheumatic mitral stenosis: correlation study of severity and platelet P-selectin expression by flow cytometry

BACKGROUND

Previous studies have demonstrated that platelet activation, evaluated by measuring the secretory substances of platelets (ie, platelet factor 4 and beta-thromboglobulin), occurs in the peripheral blood of patients with rheumatic mitral stenosis (MS). However, the differences in platelet activation between peripheral and atrial blood, and the relationship between regional left atrial platelet P-selectin expression and the severity of MS have never been investigated.

METHODS AND RESULTS

A total of 16 patients with symptomatic MS undergoing percutaneous transluminal mitral valvuloplasty were studied (group 1). The fractions of platelets expressing P selectin in the prevalvuloplasty left atrial, right atrial, peripheral venous, and arterial blood were determined by flow cytometry. The mitral valve area was calculated by means of the Doppler pressure half-time method. Peripheral venous platelet activity also was evaluated in 23 control patients (including 15 healthy volunteers who were in sinus rhythm [group 2] and 8 patients who had chronic lone atrial fibrillation [group 3]). The fraction of peripheral venous platelets expressing P selectin among group 1 patients was significantly higher than that of group 2 or 3 patients (p = 0.008). In group 1 patients, the fraction of platelets expressing P selectin in the left atrium was significantly higher than that in the right atrium, the femoral vein, or the femoral artery (p < 0.01). Correlation analysis demonstrated that there was a significantly direct relationship between the severity of MS and the fraction of left atrial platelets expressing P selectin (p = 0.01; r = -0.620). The fraction of peripheral venous platelets expressing P selectin among group 2 patients did not differ from that of group 3 patients

CONCLUSIONS

In patients with rheumatic MS, increased regional left atrial platelet P-selectin expression had a significantly direct relationship with the severity of MS. The increased regional left atrial platelet P-selectin expression was not reflected in peripheral venous blood samples.

Impaired fibrinolytic capacity in rheumatic mitral stenosis with or without atrial fibrillation and nonrheumatic atrial fibrillation

Chronic atrial fibrillation (AF) has often been associated with systemic embolization, and patients with mitral stenosis (MS) have the highest thromboembolic risk. Increased risk of thromboembolism could be in part due to impaired fibrinolytic function. Global fibrinolytic capacity (GFC) is an innovative technique for evaluating the entire fibrinolytic system. The aim of our study was to evaluate fibrinolytic activity in patients with rheumatic and nonrheumatic chronic AE To investigate fibrinolytic activity, we assessed GFC in peripheral blood samples of 32 patients with nonrheumatic AF (14 women; mean age, 56 +/- 1 years), 30 patients with rheumatic MS and AF (23 women; mean age, 35 +/- 9 years), and 32 patients with rheumatic MS and sinus rhythm (24 women; mean age, 36 +/- 8 years). The control group comprised 30 healthy adult subjects in normal sinus rhythm. Patients with chronic AF (rheumatic and nonrheumatic) had lower GFC than did the controls (P = .0001). The rheumatic AF group also showed decreased levels of GFC compared with the nonrheumatic AF group, with the rheumatic MS and sinus rhythm group, and with controls (P = .03, P = .02, P = .0001, respectively). GFC was lower in patients with rheumatic MS and sinus rhythm than in controls (P = .003). Although there were correlations between GFC and mitral valve area, transmitral mean gradient, left atrial diameter, and mitral calcification in patients with rheumatic MS, multivariate analysis showed only transmitral gradient as an independent factor affecting GFC. Patients with AF have decreased GFC, a finding that suggests the presence of a hypofibrinolytic state. Fibrinolytic dysfunction was more pronounced in rheumatic MS patients with AF than in those with nonrheumatic AF. Moreover, patients with rheumatic MS and sinus rhythm had decreased global fibrinolytic activity. Hypofibrinolysis documented by decreased GFC can be one of the important causes of increased risk of embolism in patients with AF and rheumatic MS.

Spontaneous echo contrast in descending aorta correlates with low blood-flow velocity in carotid arteries and hemostatic abnormalities

Spontaneous echo contrast in the descending aorta (DA-SEC) was examined as a possible risk factor for cerebral thromboembolism. In 19 patients (10 males, 9 females) in the chronic stage of cerebral infarction, abnormal findings by transesophageal echocardiography, flow dynamics of the common carotid artery (CCA), and hemostatic factors including blood coagulation and fibrinolysis were investigated. In nine patients, DA-SEC was detected, and SEC in left atrium (LA-SEC) was detected in nine patients. The DA-SEC positive group showed decreased blood-flow velocity (BFV) in bilateral CCA, high levels of thrombin-antithrombin III complex (TAT) and prothrombin fragment 1.2 (F1+2), a decrease in platelet count and a slight increase in D-dimer, which means an activated state of thrombin generation and resulting fibrinolysis, compared to the DA-SEC negative group. On the other hand, the LA-SEC positive group showed normal BFV in CCA and only a slight increase in D-dimer. We conclude that the condition producing DA-SEC is a stronger risk factor for cerebral infarction than that producing LA-SEC.

Correlation between quantitative left atrial spontaneous echocardiographic contrast and intact fibrinogen levels in mitral stenosis

An association between left atrial spontaneous echocardiographic contrast (LASEC) and thromboembolic events has been recognized. However, the appearance of LASEC and the assessment of its intensity are gain dependent. To evaluate the relation between LASEC intensity and coagulation activity, 11 patients with mitral stenosis underwent transesophageal echocardiography with quantitative integrated backscatter assessment of LASEC. Right and left atrial blood samples were evaluated for concentrations of coagulation markers, including intact fibrinogen, fibrinopeptide A, D-dimer, prothrombin fragment 1+2, and thrombin-antithrombin III complex. The patients were found to have significantly higher mean left atrial concentrations compared with right atrial concentrations of thrombin-antithrombin III (28.46 +/- 21.05 versus 3.21 +/- 7.16 ng/mL, respectively; P =.001) and fibrinopeptide A (32.78 +/- 17.54 versus 7.42 +/- 8.27 nmol/L, respectively; P <.001). Intact fibrinogen levels were similar in both atria, and a strong, direct correlation existed between left and right atrial intact fibrinogen levels (r = 0.78, P =.005). Quantitative integrated backscatter of LASEC correlated directly with left atrial fibrinogen level (r = 0.78, P =.013) but not with markers of thrombin generation (thrombin-antithrombin III) or activity (fibrinopeptide A). Our results confirm that patients with mitral stenosis have evidence of a regional hypercoagulable state in the left atrium. However, the intensity of LASEC assessed by quantitative integrated backscatter correlates with both right and left atrial intact fibrinogen level, a systemic marker of coagulation.

Immediate effect of balloon valvuloplasty on hemostatic changes in mitral stenosis

This study was conducted to assess right and left atrial hemostatic function in patients with mitral stenosis (MS) and to investigate the immediate effect of balloon mitral valvuloplasty (BMV) on hemostatic function. BMV was performed in 28 patients with MS (age 29 +/- 8 years) who had sinus rhythm and no left atrial (LA) thrombus. Right and left atrial biochemical markers of platelet activity (platelet factor 4 [PF4] and B thromboglobulin [BTG]), coagulation (thrombin-antithrombin III complex [TAT]), and fibrinolytic activity (D-dimer) were measured before and 30 minutes after BMV. Right atrial levels of these markers were also measured in 20 control subjects. Compared with control subjects, patients with MS had higher right atrial levels of PF4 (30 +/- 15 vs 5 +/- 2 IU/ml), BTG (231 +/- 53 vs 30 +/- 8 IU/ml), TAT (7 +/- 4 vs 2 +/- 0.3 microg/L), and D-dimer (380 +/- 145 vs 160 +/- 35 ng/ml, p < 0.0001 in all). TAT levels were higher in the left atrium than in the right atrium of patients before BMV (8 +/- 4 vs 7 +/- 4 microg/L, p < 0.0001). BMV was successful (final mitral valve area > or = 1.5 cm2 and > or = 50% increase of the initial valve area) in all patients. There was a significant reduction of LA levels of PF4 (35 +/- 8 to 26 +/- 9 IU/ml, p < 0.0001), BTG (225 +/- 41 to 196 +/- 28 IU/ml, p < 0.001), and TAT (10 +/- 5 to 7 +/- 1 microg/L, p < 0.05) in the 16 patients with LA pressure < 10 mm Hg after BMV, whereas these markers were not reduced in the 12 patients with left atrial pressure > or = 10 mm Hg after BMV. These data indicate that platelet function, coagulation status, and fibrinolytic activity are increased regionally in the left atrium and in the systemic circulation in patients with MS and sinus rhythm in the absence of LA thrombus. Successful BMV induces a significant reduction of prethrombotic status in patients with low LA pressure after the procedure. Patients with high LA pressure after BMV maintain a high prethrombotic state and may be considered at an increased risk of thromboembolism after the procedure.

Prothrombotic state and elevated levels of plasminogen activator inhibitor-1 in mitral stenosis with and without atrial fibrillation

Patients with mitral stenosis in sinus rhythm are in a prothrombotic state and have fibrinolytic dysfunction, shown by an increase in levels of the inhibitor of tissue plasminogen activator, D-dimer, and modified antithrombin III. This state may be observed even in patients without dilated left atria (diameter < or =45 mm).

Indexes of hypercoagulability measured in peripheral blood reflect levels in intracardiac blood in patients with atrial fibrillation secondary to mitral stenosis

Systemic thromboembolism is a major complication in patients with mitral stenosis, especially in those who have atrial fibrillation (AF). It has been suggested that there may be increased regional left atrial coagulation activity in such patients, despite normal systemic coagulation activity on peripheral blood sampling. Our aim was to investigate whether there were significant differences between intracardiac versus peripheral indexes of hypercoagulability in 25 patients (5 men; mean age 60 years) with mitral stenosis who were undergoing percutaneous balloon mitral valvuloplasty and who were all in chronic AF. Two days after halting warfarin therapy, intracardiac (right and left atria) and peripheral (venous and arterial) blood samples from patients were obtained and compared with levels in matched healthy controls in sinus rhythm. Thrombogenicity was assessed by levels of fibrin D-dimer, fibrinogen, indexes of platelet activation (soluble P-selectin and beta thromboglobulin [betaTG]) and indexes of endothelial dysfunction (soluble thrombomodulin [sTM] and von Willebrand factor [vWF]). There were no statistically significant differences in the various markers between the femoral vein and artery, left and right atria, and between the femoral vein and both atria (all p = NS). Plasma fibrinogen, vWf (both p <0.005), and D-dimer (p = 0.011) were significantly higher and levels of sP-selectin and sTM were lower (both p <0.005) in patients when compared with controls. There was no significant difference in plasma betaTG levels. Our results suggest that there is no significant variation in indexes of thrombogenesis, platelet activation, and endothelial dysfunction between left atrium, right atrium, and the peripheral artery or vein. Peripheral samples therefore do reflect atrial coagulation, platelet, and endothelial activities.

[Improvement in fibrinolytic function following anticoagulant treatment in chronic rheumatic atrial fibrillation]

INTRODUCTION AND OBJECTIVES

Patients with rheumatic atrial fibrillation are considered at high risk of systemic embolism and require oral anticoagulation. Fibrinolytic function has been little studied. We evaluated fibrinolytic activation markers before starting anticoagulation, at 1 and 6 months following the introduction of oral anticoagulation therapy. We analyzed the relationship with left atrial diameter and mitral area.

METHODS

Tissue plasminogen activator (tPA), its inhibitor (PAI-1), plasmin-antiplasmin complexes (PAP) and D-dimer were measured in 13 patients with rheumatic atrial fibrillation. Basal levels were compared with those found in plasma of 20 healthy subjects matched by sex and age. Transthoracic echocardiography was made.

RESULTS

A significant increase for PAI-1 and D-dimer levels were detected in patients with atrial fibrillation group (p < 0.05), with no differences in tPA and PAP concentrations. Significant correlation between left atrial diameter and basal t-PA levels was found. Levels of t-PA, PAI-1 and D-dimer decreased significantly under anticoagulation therapy, whereas PAP levels were significantly increased.

CONCLUSIONS

Patients with rheumatic atrial fibrillation show a relative hypofibrinolytic state due to elevated PAI-1 levels with no increase in PAP concentration. At six months of anticoagulation therapy, an improvement of fibrinolytic function markers was observed. This is consistent with the prophylactic effect of oral anticoagulants therapy against thromboembolic risk.

Hypofibrinolysis in atrial fibrillation

BACKGROUND

There is a high incidence of systemic embolism in patients with chronic atrial fibrillation. A hypercoagulable state has been demonstrated, but the fibrinolytic system is rarely studied.

METHODS

Plasma levels of modified antithrombin III (ATM), tissue plasminogen activator (TPA), its inhibitor (PAI-1), TPA-PAI-1 complexes and plasmin-antiplasmin complexes (PAP), d -dimer, and fibrinogen were measured in plasma from 36 patients with chronic atrial fibrillation. Fifteen patients had rheumatic mitral stenosis and 21 had nonrheumatic atrial fibrillation. Levels were compared with those found in the plasma of 20 healthy subjects. Transthoracic echocardiographic studies were done.

RESULTS

Patients with atrial fibrillation had higher plasma levels of ATM, d -dimer, PAI-1, and TPA-PAI-1 complexes than controls (P <.001). The rheumatic atrial fibrillation group also showed elevated levels of fibrinogen (P <. 05). No significant differences were found in TPA and PAP. There were no differences between rheumatic and nonrheumatic atrial fibrillation.

CONCLUSIONS

Atrial fibrillation shows a hypofibrinolytic state caused by elevated PAI-1 levels with no increase in PAP complex concentration. Elevated plasma d -dimer levels suggest increased intravascular thrombogenesis. This may contribute to increased risk of thrombosis.

Activation of blood coagulation in patients with mitral stenosis and sinus rhythm

The aim of this study was to assess whether there is blood coagulation activation in patients with mitral stenosis (MS) and sinus rhythm (SR) and to investigate the value of left atrial spontaneous echo contrast (LASEC) as a predictive sign of increased coagulation activity. Using thrombin-antithrombin III complexes and prothrombin fragment 1+2 as in vivo hemostatic markers, we concluded that there is a hypercoagulable state in patients with MS and SR when LASEC is present.

Determinants of increased regional left atrial coagulation activity in patients with mitral stenosis

BACKGROUND

Recent evidence suggests that regional left atrial coagulation activity may be increased in mitral stenosis and perhaps contribute to the pathophysiology of left atrial thrombus. However, the relation of left atrial coagulation activity to factors that predispose to left atrial thrombus formation is unknown, and the relation between left atrial and systemic coagulation activities is unresolved.

METHODS AND RESULTS

Left atrial and peripheral venous levels of the coagulation marker prothrombin fragment 1 + 2 (F1 + 2) were measured in 32 patients with mitral stenosis with normal clotting times and no left atrial thrombus who were undergoing percutaneous balloon mitral valvuloplasty. Baseline peripheral venous F1 + 2 levels, measured at the beginning of the valvuloplasty procedure, did not differ from those of 30 age-matched control patients. Prevalvuloplasty left atrial F1 + 2 levels, obtained immediately after transseptal puncture, were similar to femoral venous levels in patients without left atrial spontaneous echo contrast (LASEC) (0.81 +/- 0.32 versus 0.81 +/- 0.27 nmol/L, n = 7) but greater than femoral venous levels in patients with LASEC and either sinus rhythm (1.57 +/- 0.86 versus 0.99 +/- 0.38 nmol/L, n = 16, P < .001) or atrial fibrillation (1.52 +/- 0.69 versus 0.85 +/- 0.33 nmol/L, n = 9, P < .003). Furthermore, LASEC emerged as the only significant predictor of increased regional left atrial coagulation activity (P = .005) on stepwise multivariate logistic regression analysis.

CONCLUSIONS

Increased regional left atrial coagulation activity in mitral stenosis occurs in the presence of LASEC, is evident in either sinus rhythm or atrial fibrillation, and is associated with normal systemic coagulation activity.

Antithrombotic therapy in atrial fibrillation: a review of randomized trials with special reference to the Stroke Prevention in Atrial Fibrillation II (SPAF II) Trial

Nonvalvular atrial fibrillation is common and is associated with a high risk of system embolism. Recently, several large randomized trials have been completed that have established the efficacy of antithrombotic therapy for both primary and secondary prevention of systemic thromboembolism with an acceptable rate of bleeding complications in these patients. This section of clinical trials review summarizes data from all published randomized trials of antithrombotic therapy in atrial fibrillation. The efficacy of aspirin versus warfarin is analyzed. The role of clinical and echo-cardiographic findings to stratify patients is also highlighted. The Stroke Prevention in Atrial Fibrillation II trial is discussed in detail.

The coagulation system is activated in idiopathic cardiomyopathy

OBJECTIVES

We investigated the plasma levels of molecular markers for platelet activity and the thrombotic and fibrinolytic status in patients with hypertrophic cardiomyopathy and dilated cardiomyopathy to determine the activating site of coagulation in these disorders.

BACKGROUND

A thromboembolic event is a serious complication in patients with idiopathic cardiomyopathy. However, the activating site of the coagulation system in idiopathic cardiomyopathy has not been fully investigated.

METHODS

We determined the plasma levels of molecular markers for platelet activity (platelet factor 4 and beta-thromboglobulin), thrombotic status (fibrinopeptide A and thrombin-antithrombin III complex) and fibrinolytic status (D-dimer and plasmin-alpha 2-plasmin inhibitor complex) in 13 patients with hypertrophic cardiomyopathy, 17 patients with dilated cardiomyopathy and 20 normal subjects.

RESULTS

Plasma levels of platelet factor 4, beta-thromboglobulin and plasmin-alpha 2-plasmin inhibitor complex did not differ significantly among the three groups, whereas plasma levels of fibrinopeptide A and thrombin-antithrombin III complex in both patient groups were significantly higher than those in normal subjects. Plasma levels of D-dimer in patients with dilated cardiomyopathy were significantly higher than those in patients with hypertrophic cardiomyopathy and normal groups. In patients with hypertrophic cardiomyopathy, both fibrinopeptide A and thrombin-antithrombin III complex levels were significantly correlated with left atrial diameter. In patients with dilated cardiomyopathy, fibrinopeptide A and thrombin-antithrombin III complex levels showed a positive correlation with left ventricular end-diastolic volume and a negative correlation with fractional shortening of the left ventricle.

CONCLUSIONS

The activated coagulation system in patients with hypertrophic and dilated cardiomyopathy may be triggered by left atrial dilation in hypertrophic cardiomyopathy and left ventricular enlargement and dysfunction in dilated cardiomyopathy.

Coagulation activity is increased in the left atrium of patients with mitral stenosis

OBJECTIVES

This study investigated the hemostatic status of the right and left atria in patients with mitral stenosis.

BACKGROUND

Systemic thromboembolism is a serious major complication in patients with mitral stenosis. However, the pathogenesis of thromboembolism in mitral stenosis is not fully understood.

METHODS

We determined the plasma levels of biochemical markers for platelet activity (platelet factor 4 and beta-thromboglobulin) and status of thrombin generation (fibrinopeptide A and thrombin-antithrombin III complex) and fibrinolysis (D-dimer and plasmin-alpha 2-plasmin inhibitor complex) in specimens of blood obtained from the peripheral vein and right and left atria of 12 consecutive patients with mitral stenosis who were undergoing percutaneous mitral valvuloplasty.

RESULTS

Plasma levels of platelet factor 4, beta-thromboglobulin, D-dimer and plasmin-alpha 2-plasmin inhibitor complex in the patients did not differ significantly between the right and left atria, whereas levels of fibrinopeptide A and thrombin-antithrombin III complex in the left atrium were significantly higher than those in the right atrium (fibrinopeptide A in the left and right atria 19.35 +/- 4.64 and 6.31 +/- 0.75 ng/ml [mean +/- SE], respectively, p < 0.02; thrombin-antithrombin III complex in the left and right atria 11.45 +/- 2.29 and 3.98 +/- 0.60 ng/ml, respectively, p < 0.01). Levels of fibrinopeptide A and thrombin-antithrombin III complex in the left atrium did not correlate with mean transmitral gradient, dimension of the left atrium or reciprocal of the mitral valve area. Peripheral blood plasma levels of von Willebrand factor antigen were significantly higher in the patients than in an age-matched control group of normal subjects (168 +/- 25% and 99 +/- 7%, respectively, p < 0.05) but showed no difference in the peripheral blood and right and left atria of the patients.

CONCLUSIONS

The coagulation system is activated in the left atrium of patients with mitral stenosis even during anticoagulation.