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

The association of preoperative atrial fibrillation with post-cardiopulmonary bypass hyperfibrinolysis in rheumatic valvular heart disease patients

OBJECTIVE

The purpose of this study was to assess the fibrinolytic status after cardiopulmonary bypass in rheumatic valvular heart disease patients, and detect the associated factors of post-cardiopulmonary bypass hyperfibrinolysis.

METHODS

According to the fibrinolytic status after cardiopulmonary bypass, 203 rheumatic valvular heart disease patients were divided into two groups: hyperfibrinolysis group (H group, n = 78) and non-hyperfibrinolysis group (NH group, n = 125). The demographic characteristics, operative variables, and postoperative follow-ups were compared between these two groups.

RESULTS

The incidence of hyperfibrinolysis was 38.4% after cardiopulmonary bypass. Patients in the H group had a significant higher incidence of preoperative atrial fibrillation than patients in the NH group (92.3% vs. 55.2%, P < 0.01). Furthermore, postoperative daily drainage (655.3 ± 131.5 ml vs. 535.4 ± 161.4 ml, P < 0.01), transfusion volume of fresh frozen plasma (621.8 ± 220.2 ml vs. 455.2 ± 208.5 ml, P < 0.01), and red blood cells (5.9 ± 2.2 u vs. 4.7 ± 2.8 u, P < 0.01) was greater in the H group than in the NH group. Moreover, the logistic regression analysis revealed that preoperative atrial fibrillation was associated with post-cardiopulmonary bypass hyperfibrinolysis (OR = 19.691, 95% CI = 6.849-56.612; P < 0.05).

CONCLUSION

Preoperative artial fibrillation is associated with post-cardiopulmonary bypass hyperfibrinolysis in rheumatic valvular heart disease patients.

Exchange protein directly activated by cAMP plays a critical role in regulation of vascular fibrinolysis

Plasmin-mediated fibrinolysis at the surface of vascular endothelial cells (SVEC) plays a key role in maintaining vascular hemostasis, in which the cAMP pathway participates. After externalization to the SVEC, annexin A2 (ANXA2) serves as a platform for conversion of plasminogen to plasmin. Here we describe a regulatory role of the exchange protein directly activated by cAMP (EPAC) in ANXA2 externalization and vascular fibrinolysis. Knockout of EPAC1 in mice results in a decreased ANXA2 expression on the SVEC associated with increased fibrin deposition and fibrinolytic dysfunction. Reduced levels of EPAC1 are also found in endocardial tissues beneath atrial mural thrombi in patients. Notably, administration of recombinant ANXA2 ameliorates fibrinolytic dysfunction in the EPAC1-null mice. Mechanistically, EPAC1 regulates the SVEC plasminogen conversion depended on ANXA2. EPAC1 promotes tyrosine-23 phosphorylation of ANXA2, a prerequisite for its recruitment to the SVEC. Our data thus reveal a novel regulatory role for EPAC1 in vascular fibrinolysis.

Global assays of fibrinolysis

Fibrinolysis is an important and integral part of the hemostatic system. Acting as a balance to blood coagulation, the fibrinolytic system protects the body from unwanted thrombus formation and occlusion of blood vessels. As long as blood coagulation and fibrinolysis remain in equilibrium, response to injury, such as vessel damage, is appropriately regulated. However, alterations in this balance may lead to thrombosis or bleeding. A variety of methods have been proposed to assess fibrinolytic activity in blood or its components, but due to the complexity of the system, the design of a "gold standard" assay that reflects overall fibrinolysis has remained an elusive goal. In this review, we describe the most commonly used methods that have been described, such as thromboelastography (TEG and ROTEM), global fibrinolytic capacity in plasma and whole blood, plasma turbidity methods, simultaneous thrombin and plasmin generation assays, euglobulin clot lysis time and fibrin plate methods. All of these assays have strengths and limitations. We suggest that some methods may be preferable for detecting hypofibrinolytic conditions, whereas others may be better for detecting hyperfibrinolytic states.

Global Fibrinolytic Capacity Increased Exponentially in Metastatic Colorectal Cancer

Colorectal cancers are one of the most common malignancies associated with coagulation abnormalities ranging from asymptomatic laboratory changes to massive thromboembolism or hemorrhage. It was previously shown that global fibrinolytic was increased in non-metastatic colorectal cancer. In this study global fibrinolytic capacity was measured in patients with colorectal cancer and metastatic liver disease, which always more commonly displays various coagulation disorders. Nineteen patients with biopsy-proven colorectal cancer, 30 patients with metastatic colorectal cancer, and 20 healthy control subjects were involved into the study. Using standart silicated fibrin pellets and tissue plasminogen activator, fibrinolytic capacity of the plasmas was detected with the amount of D-dimer produced before the reaction was stopped by adding aprotinin to the medium. Mean global fibrinolytic capacity (GFC) was increased to higher levels in patients with metastatic disease compared to levels in non-metastatic disease (p<0.05). Fibrinogen/GFC ratio correlated to the increase of D-dimer levels. Global fibrinolytic capacity was much higher in metastatic disease, reflecting a progression to overt disseminated intravascular coagulation.

Heme oxygenase derived carbon monoxide and iron mediated plasmatic hypercoagulability in a patient with calcific mitral valve disease

We present a case of a patient with calcific mitral valve stenosis and plasmatic hypercoagulability. Using thrombelastography, the patient was determined to have an abnormally large velocity of plasma thrombus growth and strength with reduced vulnerability to lysis. Critically, increased carboxyhemoglobin concentration (2.4 %) was present, likely secondary to hemolysis from mitral stenosis and engagement of systemic heme oxygenase. It was determined that the patient's plasmatic hypercoagulability was in part due to carboxyhemefibrinogen formation and iron-enhancement of coagulation via two thrombelastographic methods. In conclusion, future investigation of the involvement of both carbon monoxide and iron mediated hypercoagulability in the setting of stenotic valve disease is warranted.

Mean platelet volume in patients with nonvalvular atrial fibrillation

The procoagulant and prothrombotic states in patients with chronic atrial fibrillation are higher than those in patients with normal sinus rhythm. Mean platelet volume (MPV) which is a marker of platelet function and activation can reflect changes either in the level of platelet stimulation or the rate of platelet production. In this study, we aimed to assess and compare the hematologic parameters of routine complete blood count analysis in elderly patients with nonvalvular atrial fibrillation and control individuals with normal sinus rhythm. One hundred and seven consecutive patients with nonvalvular chronic atrial fibrillation and 112 age and sex-matched control individuals with normal sinus rhythm were retrospectively included in the study from the outpatient cardiology clinic. Hematological variables, including MPV, platelet count, red blood cell and white blood cell count were measured in all patients and control individuals. Presence of coronary artery disease, hypertension, sex, hyperlipidemia, diabetes mellitus, smoking status, hematocrit and platelet count were comparable between two groups (P>0.05 for all). However, MPV and white blood cell count were significantly higher in patients with atrial fibrillation compared to those without atrial fibrillation. Logistic regression analysis revealed that white blood cell count and MPV significantly and independently associated with atrial fibrillation. We have shown that MPV and white blood cell count is independently associated with chronic nonvalvular atrial fibrillation. To improve the clinical utility of MPV and role of inflammation in the pathogenesis of atrial fibrillation, further studies are needed to be carried out.

Patients with paroxysmal atrial fibrillation but not paroxysmal supraventricular tachycardia display evidence of platelet activation during arrhythmia

It is well known that chronic atrial fibrillation (CAF) and paroxysmal atrial fibrillation (PAF) are associated with hypercoagulable state. However, pathological hemostatic changes during the paroxysmal supraventricular tachycardia (PSVT) have not yet been elucidated. To determine platelet activity in patients with PSVT, PAF and CAF, we examined the levels of beta-thromboglobulin (BTG) and platelet factor 4 (PF4) during tachyarrhythmia attacks. We measured the levels of BTG and PF4, as an index of platelet activation in 15 patients with PAF (9 men, mean age 45+/-11), and 14 patients with PSVT (8 men, mean age 40+/-10). Levels were compared to 22 age and sex matched healthy controls in sinus rhythm and with 25 patients with CAF (16 men, mean age 51+/-12). Blood samples were taken during arrhythmia and 24 hours after conversion to sinus rhythm. Patients taking medications or have clinical conditions that may affect the BTG and PF4 levels were excluded. In patients with PAF, BTG and PF4 levels were significantly higher than in controls (p<0.009, and p=0.002, respectively), and in patients with PSVT (p<0.004, and p=0.009, respectively), however, BTG and PF4 levels were significantly lower than CAF patients (p=0.002, and p=0.02, respectively). Moreover, BTG and PF4 levels were significantly decreased 24 hours after conversion to sinus rhythm (p<0.0001), and p=0.004, respectively). Although BTG and PF4 levels in patients with PSVT were significantly lower than in patients with PAF (p=0.04, and p=0.009, respectively) and CAF (p=0.0001, and p=0.0001, respectively), BTG and PF4 levels were similar to controls and did not change significantly after recovery to sinus rhythm (p=NS for all). These results indicate that there was no platelet activation in patients with PSVT during tachyarrhythmia but significantly increased platelet activity in PAF and CAF patients. There was a significant decrement of the platelet activity to a level of control subjects twenty-four hours after cardioversion of PAF.

Alterations of von Willebrand Factor and Ristocetin Cofactor Activity During Atrial Fibrillation

The aim of this study was to assess the plasma levels of von Willebrand factor antigen and ristocetin cofactor activity, which are well-known markers of endothelial function, in atrial fibrillation (AF) with or without mitral stenosis (MS). Forty-two patients (16 patients with MS and AF [MS(+)AF(+)], 13 patients with nonvalvular AF [MS(−)AF(+)], and 13 patients with MS and sinus rhythm [MS(+)AF(−)]) were included. Von Willebrand factor antigen levels and ristocetin cofactor activities in all participants were assessed. Overall, von Willebrand factor antigen levels and ristocetin cofactor activities in the AF(+) patients were higher than in the AF(−) patients ( P = .003 and P = .002, respectively). Von Willebrand factor antigen levels and ristocetin cofactor activities in the 3 groups were found to be different ( P = .012 and P = .01, respectively). Von Willebrand factor antigen levels were similar between the MS(+)AF(+) and MS(−)AF(+) groups and were higher than that of the MS(+)AF(−) group. Ristocetin cofactor activity in the MS(−)AF(+) group was significantly higher than in the other 2 groups. The ristocetin cofactor activity and von Willebrand factor antigen levels were significantly higher in diabetic or hypertensive patients than in nondiabetic or normotensive patients. According to the results of this study, circulating von Willebrand factor antigen levels and plasma ristocetin cofactor activities are affected by the presence of AF, MS, and associated comorbidities including type 2 diabetes mellitus and systemic hypertension. Further studies are needed to assess the role of von Willebrand factor antigen and ristocetin cofactor activity in predicting vascular thrombotic events in AF, MS, systemic hypertension, and diabetes mellitus.

Unchanged global fibrinolytic capacity during the course of hematopoietic stem cell transplantation

Hemostatic changes due to vascular endothelial damage are seen during the course of hematopoietic stem cell transplantation (HSCT). The fibrinolytic response to ongoing hemostatic activation in HSCT remains to be elucidated. Global fibrinolytic capacity (GFC) is a novel method, which reflects the amount of generated D-dimer when fibrinolysis of a freeze-dried fibrin clot is stopped by introducing aprotinin. GFC is sensitive to all the factors involved in the process of fibrinolysis. The aim of this study was to serially assess GFC at certain critical time points (days -1, +7, +14, +21 prior to and following stem cell infusion) during the course of HSCT. The study group comprised 16 patients with hematological malignancies (11 women, five men; median age 32+/-9 years) in whom HSCT had been performed. Thirty healthy adults (21 women, nine men; median age 31+/-7 years) served as controls. In this study, global fibrinolytic response, as reflected by GFC, was unchanged despite ongoing hemostatic activation, as indicated by D-dimer, moreover GFC remained stable, despite the development of thrombocytopenia associated with HSCT prior to platelet engraftment. Our results indicate that a global fibrinolytic response was impaired as a compensatory response to endothelial activation and to other hemostatic changes seen in HSCT. Further studies in larger HSCT populations are warranted to better understand the implications of these findings.

Gelatinolytic and fibrinolytic activity in fresh-frozen plasma

Fresh-frozen plasma (FFP) was evaluated for gelatinolytic and fibrinolytic activity. Gelatin zymography revealed that gelatinase A (MMP-2) was constitutively present in FFP whereas gelatinase B (MMP-9) was present at variable levels. The presence of MMP-9 likely represents differential release from neutrophils during FFP collection or processing. Although fibrin matrices generated from FFP or freshly prepared plasma contained characteristic crosslinked gamma-gamma dimers and beta-monomers, matrices generated from FFP were resistant to spontaneous plasmin-dependent fibrinolysis. This observation likely stems from the plasminogen activator instability and could potentially lead to a hypofibrinolytic state. The impact of these in vitro findings to protease balance in patients receiving multiple FFP doses remains to be determined.

Fibrinolytic activity in multiple myeloma

The incidence of thromboembolic events is high as a result of disease, disease-related complications, and therapy in multiple myeloma (MM). In patients with hematologic tumors, impaired fibrinolysis may be present and may contribute to the development of thrombotic complications. Therefore, we designed a study to investigate fibrinolytic activity in MM. We compared plasma levels of interleukin (IL)-6, C-reactive protein (CRP), IL-1beta, IL-11, tissue plasminogen activator (tPA) activity, plasminogen activator inhibitor-1 (PAI-1) activity, and global fibrinolytic capacity (GFC) in patients with MM (n = 66) and in control subjects (n = 18). The prevalence of venous thromboembolism was 4.5%, with a median follow-up period of 7 months in our myeloma group. Results are given as mean (median, range). Plasma levels of IL-6 (8.27 +/- 0.74 [9.65, 0.90-13.32] pg/mL versus 2.64 +/- 0.66 [1.80, 0.10-11.86] pg/mL, P < 0.001), CRP (45.57 +/- 9.92 [21.00, 1.34-330.00] mg/L versus 1.96 +/- 0.50 [1.05, 0.19-8.03] mg/L, P < 0.001), PAI-1 (7.40 +/- 0.67 [5.57, 2.40-31.80] IU/mL versus 4.73 +/- 0.65 [3.60, 2.32-11.00] IU/mL, P < 0.01), GFC score (1.90 +/- 0.02 [2, 1-3] versus 2.50 +/- 0.14 [3, 1-3], P < 0.001) were increased compared with controls. In patients with MM, the level of IL-6 was positively correlated with CRP (r = 0.66, P < 0.001), IL-1beta (r = 0.29, P < 0.05), and PAI-1 (r = 0.35, P < 0.01) and negatively correlated with GFC (r = -0.37, P < 0.01). CRP level was positively correlated with plasma PAI-1 level (r = 0.40, P < 0.01) and negatively correlated with GFC (r = -0.44, P < 0.001). A significant negative correlation between PAI-1 level and GFC (r = -0.75, P < 0.001) was also detected. IL-1beta levels were negatively correlated with tPA level (r = -0.26, P < 0.05). These results suggest that patients with myeloma have a decreased fibrinolytic activity mainly because of increased PAI-1 activity. In MM, increased PAI-1 activity seems to be related with elevated IL-6 level. MM should be considered as a hypercoagulable state as a result of both increased procoagulant activity and decreased fibrinolytic activity. Achieving a plateau by means of conventional chemotherapies does not improve the decreased fibrinolytic activity.