The role of clinical parameters and of CYP2C19 G681 and CYP4F2 G1347A polymorphisms on platelet reactivity during dual antiplatelet therapy.

Dual antiplatelet therapy with aspirin and clopidogrel is used to lower the risk of arterial thrombosis. However, this strategy is not always successful owing to high interindividual variability in response to antiplatelet therapy. To evaluate an impact of CYP2C19 G681A and CYP4F2 G1347A polymorphisms and clinical factors on dual antiplatelet effect of clopidogrel and aspirin. Totally 89 patients who continued dual aspirin and clopidogrel antiplatelet therapy for at least of 14 days were included into the further study. Test for platelet aggregation was performed according to the classical Born method. Genotyping of CYP2C19*2 and CYP2C19*3 and CYP4F2*3 was done by using commercial probes from Applied Biosystems (UK). Patient age, weight and body weight index did not correlate significantly with platelet aggregation level both induced by ADP and epinephrine (P > 0.05). Serum concentration of creatinine, diabetes, angiotensin II receptor blockers, B-blockers, statin or omeprazole use had no significant effect on platelet aggregation. The users of angiotensin-converting enzyme inhibitors had lower platelet aggregation levels with epinephrine vs. nonusers: 28.80 ±â€Š13.25 vs. 51.15 ±â€Š23.50, P < 0.03, respectively. Platelet aggregation with ADP was higher in CYP2C19*1*2 genotype carriers than in CYP2C19*1*1 carriers (P = 0.01). Platelet aggregation with epinephrine was higher in CYP4F2 GA genotype carriers than in GG (P = 0.04) or AA (P = 0.01) carriers. Our study confirms that CYP2C19 G681A genotype has an impact on antiplatelet effect of clopidogrel. The novelty is that the platelet aggregation after induction with epinephrine is influenced by CYP4F2 G1347A genotype.

The effect of CYP2C9, VKORC1 and CYP4F2 polymorphism and of clinical factors on warfarin dosage during initiation and long-term treatment after heart valve surgery.

The dosage of warfarin is restricted due to its narrow therapeutic index, so, the required dose must be adapted individually to each patient. Variations in warfarin dosage are influenced by genetic factors, the changes in patient diet, anthropometric and clinical parameters. To determine whether VKORC1 G3730A and CYP4F2 G1347A genotypes contribute to warfarin dosage in patients during initiation and long-term anticoagulation treatment after heart valve surgery. From totally 307 patients, who underwent heart valve surgery, 189 patients (62 %) who had been treated with warfarin more than 3 months, were included into the study. A hierarchical stepwise multivariate linear regression model showed, that during initiation clinical factors can explain 17 % of the warfarin dose variation. The addition of CYP2C9 and VKORC1 G-1639A genotype raises the accuracy about twice-to 32 %. The CYP4F2 G1347A genotype can add again about 2-34 %. During long-term treatment clinical factors explain about 26 % of warfarin dose variation. If the CYP2C9 *2, *3, VKORC1*2 alleles are detected, model can explain about 49 % in dose variation. The *3 allele of VKORC1 raises the accuracy by 1-50 %. The carriers of CYP4F2 A1347A genotype required higher daily warfarin doses during initiation of warfarin therapy after heart valve surgery than comparing to G/G and G/A carriers, but during the longer periods of warfarin use, the dosage of warfarin depended significantly on VKORC1 *3 allele (G3730A polymorphism) and on the thyroid stimulating hormone level in the blood plasma.

The combined effects of clinical factors and CYP2C9 and VKORC1 gene polymorphisms on initiating warfarin treatment in patients after cardiac valve surgery.

BACKGROUND AND AIM OF THE STUDY: Recent studies have shown that, after heart valve surgery, patients may require a more precise warfarin dosage than their non-surgical counterparts. The study aim was to analyze the influence of certain clinical factors and CYP2C9 and VKORC1 gene polymorphisms on the efficacy of initiation of warfarin treatment in patients after cardiac valve surgery. METHODS: Following heart valve surgery, a total of 185 patients was genotyped for the CYP2C9*1, *2, *3 alleles and for VKORC1 (G-1639A) gene promoter polymorphism. RESULTS: A hierarchical stepwise multivariate linear regression model was used to evaluate factors affecting the optimal warfarin dosage. Patient age and body weight, together with hepatic malfunction in the cohort population, accounted for 12% of the variation in warfarin dosage (R2 = 0.119). The introduction of concomitant medications, more than doubled (R2 = 0.316) the accuracy of the dosage algorithm. Medications such as cephalosporin, amiodarone, loop diuretics, ibuprofen or diclofenac, omeprazole and beta-blockers had significant effects on the warfarin daily dosage in this model. However, the greatest accuracy was obtained when the patient's CYP2C9 and VKORC1 genotype was introduced into the formula as the critical factor (R2 = 0.429). CONCLUSION: The study results suggested that, after cardiac valve surgery, by combining the clinical, genetic and anthropometric data of a patient, the warfarin dose may be estimated to 43% accuracy at the initiation of anticoagulant therapy.

Coagulation alterations in treating arrhythmias with radiofrequency ablation.

OBJECTIVE: To determine an influence of radiofrequency ablation on changes in coagulation system. MATERIAL AND METHODS: We investigated 30 patients with cardiac arrhythmias. Platelet aggregation, fibrinogen and D-dimer level were analyzed before, right after, 24 and 72 h after radiofrequency ablation. Platelet aggregation was explored in whole blood and platelet-rich plasma using adenosine diphosphate (ADP), epinephrine, and collagen for induction. RESULTS: Platelet aggregation induced by ADP and collagen in whole blood plasma increased significantly (P<0.01) (by 45% and 43%, respectively) in 24 h after radiofrequency ablation and remained increased in 72 h after radiofrequency ablation (by 11% and 35%, respectively) (P<0.01) as compared with baseline results. Spontaneous aggregation of platelet-rich plasma as well as ADP- and collagen-induced platelet aggregation tended to decrease right after radiofrequency ablation. Epinephrine-induced platelet aggregation significantly decreased by 17.5% after radiofrequency ablation (P<0.01) and started to increase in 24 h after radiofrequency ablation. In 72 h after radiofrequency ablation, platelet aggregation induced by different agonists increased by 7-45% significantly (P<0.05), and values were higher than baseline ones. Fibrinogen level after radiofrequency ablation did not differ from that of the baseline (3.08+/-0.7 g/L), but D-dimer level increased significantly (from 0.39+/-0.3 to 1.29+/-2.4 mg/L, P<0.01). In 24 h after radiofrequency ablation, an increase in fibrinogen level and a decrease in D-dimer level were found. Fibrinogen level increased to 3.32+/-0.6 g/L significantly in 72 h after radiofrequency ablation (P<0.05). Meanwhile, D-dimer concentration decreased to 0.78+/-0.8 mg/L, but it was still significantly higher (P<0.05) than the baseline value. CONCLUSION: Despite diminished platelet aggregation and increased D-dimer level right after radiofrequency ablation, a risk of thrombosis increased in the next few days after radiofrequency ablation.

[The impact of acute cerebral blood flow disturbances on platelet aggregation]. / Uminiu smegenu kraujotakos sutrikimu itaka trombocitu agregacijos intensyvumui.

OBJECTIVE: To determine the changes in platelet function, manifesting as deviations of their aggregation intensity, in persons with acute ischemic stroke and transient ischemic attacks, to evaluate the effect of aspirin on platelet aggregation, dependent upon degree of cerebral blood flow disturbances and patient's gender, and to compare these changes with those in healthy persons. MATERIAL AND METHODS: We examined 50 patients aged 33 to 98 years (mean age, 63.7+/-2.1 years; 20 men and 30 women) with cerebral blood flow disturbances during acute period (18 with transient ischemic attacks and 32 with ischemic stroke). The diagnosis was confirmed by computer tomography and other clinical examinations. Adenosine diphosphate-, epinephrine-, and collagen-induced platelet aggregation was assessed in platelet-rich plasma. Twelve patients used aspirin at prophylactic doses (100-150 mg/d), and 38 patients did not use. The control group consisted of 25 healthy persons aged 31-64 years (mean age, 45.4+/-1.9 years; 17 men and 8 women). RESULTS: Increased platelet aggregation induced by all three inducers was significantly more frequent in stroke group. Platelet reaction to collagen was more expressed. Aspirin suppressed aggregation, but did not protect against development of ischemic stroke. Higher activity of platelet function during ischemic stroke was observed in platelets from men's plasma. CONCLUSIONS: During acute period, platelet aggregation in platelet-rich plasma statistically significantly increases in the stroke group, independently of the severity of the disease. A part of patients, using recommended dose of prophylactic aspirin, developed ischemic stroke. The effect of aspirin on platelets was more pronounced in women than men.

Brain natriuretic peptide and other cardiac markers predicting left ventricular remodeling and function two years after myocardial infarction.

BACKGROUND: Left ventricular remodeling is a complex pathologic process of progressive left ventricular dilatation, leading to dysfunction and heart failure in patients after myocardial infarction. OBJECTIVE: To evaluate biochemical markers, reflecting cardiac remodeling process after first myocardial infarction and compare those markers with clinical characteristics of left ventricular remodeling. MATERIAL AND METHODS: Brain natriuretic peptide, troponin I, creatine kinase, creatine kinase MB mass, lactate dehydrogenase levels were measured in 30 patients with acute myocardial infarction on days 1, 2, 3-7 . Brain natriuretic peptide was measured at 3 months, 6 months, and 2 years after myocardial infarction. Echocardiographic parameters of left ventricular remodeling were determined in acute phase (day 1-3), at 3 months, 6 months, and 2 years after MI. RESULTS: In acute phase, brain natriuretic peptide level progressively increased according to worsening of left ventricular geometry: in normal left ventricle geometry group, brain natriuretic peptide level was 84.1 (58.7-121) pg/mL, in concentric remodeling group - 125 (69.2-165) pg/mL, in concentric hypertrophy group - 128 (74-368) pg/mL, and in eccentric hypertrophy group - 470 (459-494) pg/mL, P=0.02. Patients who had increased left ventricular end diastolic diameter index during 2-year period had higher brain natriuretic peptide level in the acute phase (584 (249-865) pg/mL vs. 120 (67-202) pg/mL, P=0.04) and also higher peak lactate dehydrogenase and troponin I levels. CONCLUSIONS: Brain natriuretic peptide level in acute phase of myocardial infarction is strongly associated with the markers of myocardial injury and related to left ventricular geometry changes and remodeling. Brain natriuretic peptide together with troponin I levels in acute phase of myocardial infarction might be useful in predicting subsequent cardiac function.

Influence of radiofrequency catheter ablation on platelet aggregation.

The objective of this article was to find out how radiofrequency catheter ablation (RFA) influences platelet aggregation (PA), and the dependence on the total energy (TE) of RFA used and the cause of arrhythmia. We investigated 97 patients. PA was analyzed before, after, and in 24 hours after RFA. ADP- and epinephrine-induced PA significantly decreased after RFA by 5% and 8.9% (P < .001), respectively, and increased in 24 hours close to baseline. PA induced by ADP and collagen did not radically depend on the TE. Epinephrine-induced PA decreased after RFA by 0%, 8% (P < .05), and 16.9% (P < .01) in groups of patients where the TEs used were <4000 J, 4000 to 15,000 J, and >15,000 J, respectively. There were no significant differences in PA between groups based on the cause of arrhythmia. ADP- and epinephrine-induced PA significantly decreased after RFA and returned close to baseline in 24 hours. Epinephrine-induced PA was inversely associated with the TE used for RFA.

Influence of early re-infusion of autologous shed mediastinal blood on clinical outcome after cardiac surgery.

Various strategies have been proposed to decrease allogeneic blood transfusion requirements after cardiac surgery. The aim of the study was to evaluate the efficacy of collected and re-infused autologous shed mediastinal blood on a patient's postoperative course. Ninety patients who underwent heart surgery with cardiopulmonary bypass (CPB) were studied. The patients were divided into two groups: Group 1 (n=41) received the centrifuged autologous shed mediastinal blood collected from the cardiotomy reservoir 4 hours after surgery; in Group 2 (n=49) all shed mediastinal blood was discarded (control group). Haemoglobin (Hb), haematocrit (Hct), C-reactive protein values, and leucocyte count were compared before surgery, at 4 h and 20 h after surgery, and on the fifth postoperative day. We have measured serum procalcitonin (PCT) concentration at 4 h and 20 h after CPB. We assessed drained blood loss within 20 postoperative hours. Leucocyte count, Hb, Hct values, C-reactive protein, and procalcitonin concentration did not differ between the groups before and at 4 h after surgery. Hb, Hct level, and leucocyte count were similar at 20 hours and on the fifth day after surgery. At 20 hours after surgery, an increase of serum PCT concentration (>0.5-2 ng/mL) was more frequent in Group 2 (58.3% vs. 33.3%; p = 0.03). On the fifth postoperative day, C-reactive protein concentration was lower in Group 1 (71.74 +/- 15.23; p <0.01) compared to Group 2 (93.53 +/- 20.3). Postoperative blood loss did not differ between the groups. Requirement for allogeneic blood transfusion was significantly lower in Group 1 (14.6% vs. 38.8%; p < 0.02). Patients in Group 1 developed less infective complications compared with Group 2 (2.4% and 16.3%, respectively; p < 0.05). The length of postoperative in-hospital stay was shorter in Group 1 compared with Group 2 (9.32 +/- 2.55 and 16.45 +/- 6.5, respectively; p < 0.05). We conclude that postoperative re-infusion of autologous red blood cells processed from shed mediastinal blood did not increase bleeding tendency and systemic inflammatory response and was effective in reducing the requirement for allogeneic transfusion, the rate of infective complications and the length of postoperative in-hospital stay.

Influence of aspirin or heparin on platelet function and postoperative blood loss after coronary artery bypass surgery.

The aim of the study was to assess the effect of aspirin or heparin pretreatment on platelet function and bleeding in the early postoperative period after coronary artery bypass grafting (CABG) surgery. Seventy-five male patients with coronary artery disease who underwent CABG with cardiopulmonary bypass (CPB) were studied. The patients were divided into three groups: Group 1 (n=25) included patients receiving aspirin pretreatment, Group 2 (n=22) received heparin pretreatment, and Group 3 (n=28) included patients who received no antiplatelet or anticoagulant pretreatment. Twenty-four hours after surgery, all patients were administered aspirin therapy that was continued throughout their hospitalization period. We assessed the following preoperative blood coagulation indices: activated partial thromboplastin time (aPTT), international normalized ratio (INR), and fibrinogen. We compared platelet count and platelet aggregation induced by adenosinediphosphate (ADP) before surgery, 1 h after surgery, 20 h after surgery and on the seventh postoperative day. We assessed drained blood loss within 20 postoperative hours. Preoperative blood coagulation indices did not differ among the groups. Platelet count was also similar. One hour after surgery, platelet count significantly decreased in all groups (p<0.001), after 20 postoperative hours it did not undergo any marked changes, and on the seventh postoperative day, it significantly increased in all groups (p<0.001). Before surgery, the lowest index of ADP-induced platelet aggregation was found in Group 1 (p<0.05). One hour after surgery, platelet aggregation significantly decreased in all groups, most markedly in Group 3 (p<0.001), yet after 20 h, its restitution tendency and a significant increase in all groups was noted. On the seventh day, a further increase in the statistical mean platelet aggregation value was noted in Groups 2 and 3. Comparison of platelet aggregation after 20 postoperative hours and on the seventh day after surgery revealed a significantly higher than 10% increase of the index in 32% of patients in Group 1 (p<0.05), 27.3% of patients in Group 2 (p<0.05) and in 35.7% of patients in Group 3 (p<0.001). The lowest statistically significant value of postoperative blood loss was noted in Group 2 (p<0.01). Our study has shown that aspirin or heparin pretreatment had no impact on the dynamics of platelet function in the early postoperative period after CABG. The lowest postoperative blood loss was noted in patients pretreated with heparin.

[Influence of preoperative treatment with aspirin or heparin on platelet function and intensity of postoperative bleeding in early period after coronary artery bypass surgery]. / Aspirino ar heparino, vartojamo iki operacijos, itaka trombocitu funkcijai bei kraujavimo intensyvumui po aortos vainikiniu jungciu operaciju.

OBJECTIVE: The aim of the study was to evaluate influence of preoperative treatment with aspirin or heparin on platelet function and intensity of postoperative blood loss in early period after coronary artery bypass grafting (CABG). MATERIAL AND METHODS: Study involved 75 patients (men) with ischemic heart disease, who underwent CABG. Patients were divided into three groups: aspirin pretreated (I group, n=25), heparin pretreated (II group, n=22) and III group (n=28) had no antiplatelet or anticoagulant pretreatment. At 24 h after surgery all patients started treatment with aspirin (ASS 100, Bayer), which lasted all hospitalization period. We have evaluated preoperative coagulation parameters: activated partial thromboplastin time, international normalized ratio, and fibrinogen level. Also we have compared platelet count, platelet aggregation induced by adenosine diphosphate during preoperative period, at 1 h, 20 h and at 7 day after surgery. RESULTS: Preoperative coagulation parameters were comparable in all groups. Platelet count was also similar. One hour after surgery platelet count remarkably decreased in all groups (p<0.001); at 20 hours after surgery changes remained the same and at 7 day a significant increase was observed in all groups (p<0.001). The lowest rate of preoperative platelet aggregation was found in I group (p<0.05). At 1 hour after surgery platelet aggregation decreased significantly in all groups, particularly in III group (p<0.001). At 20 hours after surgery platelet aggregation had a tendency to reach previous level and increased substantially in all groups. We have found more than 10% increase in platelet aggregation at 7 day compared to 20 hours postoperatively. These changes were observed in 32% (p<0.05), 27.3% (p<0.05) and 35.7% (p<0.001) of patients in the group I, II and III, respectively. Postoperative blood loss was significantly lowest in II group (p<0.01). CONCLUSIONS: Our investigation shows that preoperative treatment with aspirin or heparin had no remarkable influence on dynamics of platelet function in early period after CABG. The least blood loss was observed in patients with heparin pretreatment.

Brain natriuretic peptide and other cardiac markers in predicting left ventricular remodeling in patients with the first myocardial infarction.

UNLABELLED: Left ventricular remodeling is a complex pathologic process of progressive dilatation, leading to dysfunction and heart failure in patients with acute myocardial infarction. The aim of our study was to determine and evaluate biochemical markers, reflecting cardiac remodeling process in the patients with the first myocardial infarction and to compare those markers with clinical characteristics of left ventricular remodeling. MATERIAL AND METHODS: Concentrations of brain natriuretic peptide and markers of myocardial necrosis were measured on 1st , 2nd and 7th day after the onset of the first acute myocardial infarction, as well as after 3 and 6 months in 30 patients. Parameters of left ventricular remodeling were determined by echocardiographic investigation, which was performed in the acute phase and after 3 and 6 months. RESULTS: Brain natriuretic peptide concentration was found to be related to the left ventricular geometry in the acute phase: brain natriuretic peptide peak level was lower in the patients with the normal left ventricular geometry than in the patients with the changed left ventricular geometry (140.6+/-63.3 pg/ml vs. 385.7+/-283.9, p<0.05). Brain natriuretic peptide concentration in the acute phase was higher in the patients who had increased left ventricular end diastolic diameter through 6-month period (348.9+/-309.4 pg/ml vs. 145.1+/-109.6 pg/ml, p<0.05). Higher troponin I (58.8+/-33.6 ng/ml vs. 30.9+/-31.3 ng/ml, p<0.05) and troponin T (4.5+/-2.2 ng/ml vs. 1.9+/-2.0 ng/ml, p<0.05) levels were also associated with left ventricular dilatation through 6 months after myocardial infarction. CONCLUSIONS: Brain natriuretic peptide level in acute phase of myocardial infarction is related to the left ventricular geometry changes and remodeling. Brain natriuretic peptide together with other cardiac markers might be useful in predicting subsequent cardiac function.

Alterations of platelet aggregation while treating cardiac arrhythmias with radiofrequency ablation.

OBJECTIVE: To find out if radiofrequency ablation as method of treatment of cardiac arrhythmia influences platelet aggregation and if intensity of this process depends on the number of radiofrequency ablation episodes for one patient. MATERIAL AND METHODS: We analyzed platelet aggregation before, right after and in 24 hours after radiofrequency ablation in whole blood and platelet rich plasma in 39 cases with cardiac arrhythmias. Adenosine diphosphate and adrenaline were used for aggregation induction. Three groups of patients were formed based on the number of radiofrequency ablation episodes: A-- <10, B--10-20, C-- >20 for one patient. RESULTS: We detected a decrease in spontaneous, adenosine diphosphate and adrenaline induced platelet aggregation in plasma right after radiofrequency ablation, and also the same tendency was noted in adenosine diphosphate induced aggregation in whole blood. In 24 hours after radiofrequency ablation platelet aggregation tended to return to pre-radiofrequency ablation levels. Based on the number of radiofrequency ablation episodes we detected significant changes in spontaneous and adrenaline-induced aggregation in plasma. In group A adrenaline induced aggregation after radiofrequency ablation increased by 0.4%, in group B it decreased by 15.7% and in group C it decreased by 19.4% from pre-radiofrequency ablation level (p<0.05, between groups A and C). Spontaneous platelet aggregation after radiofrequency ablation decreased in group A 41.9%, in group B--20.8% and in group C--18.4% from pre-radiofrequency ablation level (p<0.05 between groups A and C). The greater decrease in adenosine diphosphate induced aggregation in plasma and in whole blood was detected in the group with larger number of radiofrequency ablation episodes. CONCLUSIONS: This study found that platelet aggregation decreased in plasma and in whole blood after radiofrequency ablation. And this alteration was significant in groups B and C, when the number of radiofrequency ablation episodes were >10. In 24 hours platelet aggregation increased again to pre- radiofrequency ablation level.

[Role of tissue factor in atherothrombosis]. / Audiniu faktoriaus vaidmuo aterotrombozes procese.

Tissue factor is a key enzyme in coagulation process. It is primary known as a cofactor for factor VIIa-mediated triggering of blood coagulation, which proceeds in a cascade of extracellular reactions. Tissue factor forms a catalytic complex with VIIa and intitiates coagulation by activating factor IX and X, ultimately resulting in thrombin formation. Being a transmembranic glycoprotein it takes a signalling information to another cell activity after endothelium or other tissue damage. Tissue factor plays a pivotal role in blood clotting physiology and pathology especialy in atherothrombosis. Thrombogenic tissue factor on cell-derived microparticles is present in the circulating blood of patients with acute coronary syndromes. Tissue factor is found in adventitia of blood vessels and the lipid core of atherosclerotic plaques (but not in vascular cells contacting directly with blood). Although the molecular mechanisms responsible for these phenomena remain unclear, it is thought that they are brought about by the action of intracellular signaling, resulting in gene transcription and subsequent protein synthesis. By expressing on monocyte or macrofage cell membrane surface it is involved in proinflammatory action and plaque destabilisation. This shifted the emphasis to investigations of what happened on the cell surface, and later to the cell biology of tissue factor and its inducibility in monocytes/macrophages and endothelial cells. Recent studies have suggested that tissue factor also plays non-hemostatic roles in blood vessel development, tumor angiogenesis and metastasis, inflamation. Tissue factor upregulates a number of genes involved in regulation of growth, transcription, and cellular motility, as well as cytokines, makes it possible to suggest a link between the formation of the tissue factor / VIIa complex and the cellular processes. Regulation of tissue factor activity by natural tissue factor pathway inhibitor (synthesized by vascular endothelial cells) or by special drugs is a new insight in thrombosis and vessel reocclusion preventive therapy. Tissue factor concentration in circulating blood has a higher informativity comparing to troponine and CRB values.