Low rate of venous thromboembolism in asymptomatic relatives of probands with factor V Leiden mutation.
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Factor V↗
Biomedical subjects
A Girolami
Publications and source records attributed to A Girolami.
Treatment of intermittent claudication with physical training, smoking cessation, pentoxifylline, or nafronyl: a meta-analysis.
BACKGROUND: There is no consensus on the efficacy of physical training, smoking cessation, and pharmacological therapy (pentoxifylline or nafronyl oxalate) in the treatment of patients with intermittent claudication at Fontaine stage II of disease. METHODS: A MEDLINE and manual search was used to identify relevant publications. Uncontrolled or retrospective studies, double reports, and trials without clinically meaningful outcomes were excluded. Included studies were graded level 1 (randomized and double- or assessor-blind), level 2 (open randomized), or level 3 (nonrandomized). Pain-free and total walking distance were the main outcomes considered; when feasible, end-of-treatment results were combined with appropriate meta-analytical procedures. RESULTS: In 5 level 2 studies, physical training increased pain-free and total walking distance significantly (139.0 m [95% confidence interval {CI}, 31.0 to 246.9 m] and 179.1 m [95% CI, 60.2 to 298.1 m], respectively). In a level 3 study, smoking cessation resulted in a nonsignificant increase in total walking distance of 46.7 m (95% CI, -19.3 to 112.7 m). In 6 level 1 studies, pentoxifylline increased both pain-free and total walking distance by 21.0 m (95% CI, 0.7 to 41.3 m) and 43.8 m (95% CI, 14.1 to 73.6 m), respectively. In 4 level 1 trials, nafronyl significantly increased pain-free walking distance (58.6 m [95% CI, 30.4 to 86.8 m]) and total walking distance (71.2 m [95% CI, 13.3 to 129.0 m]). CONCLUSIONS: Physical training increased pain-free and total walking distance in level 2 studies. Only level 3 studies support the usefulness of smoking cessation. In level 1 studies, pentoxifylline and nafronyl increased pain-free and total walking distance, but the average effects were relatively small.
Clinical Trials as Topic↗
Psychological aspects and coping of parents with a haemophilic child: a quantitative approach.
Although haemophilia is a relatively rare hereditary disease, and is curable by blood products, the psychological and social problems of haemophilic patients and of their families are always serious. Anxiety for the risks of bleedings and the fear for infections transmitted by blood products cause stress and difficulty in coping with the situation. The aim of this paper is to assess resources, stress, and coping in parents with a haemophilic child. In order to measure the dimensions related to family stress and resources, social desirability, tendency to depression, and anxiety, the subjects were administered the short-form of the Questionnaire on Resources and Stress by Friedrich et al. revised by Saviolo & Cristante, along with the Social Desirability Scale, the Beck Depression Inventory, and the Ipat Anxiety Scale. The subjects of this study were 20 couples who were the parents of haemophilic sons. We analysed how the parents perceived the behavioural characteristics of their child, the differences between mothers and fathers in the questionnaire scores, and the correlation among the considered dimensions. The results show that the parents paid great attention to the problems of their sons, but mothers were more depressed and anxious about the disease of their child.
Adaptation, Psychological↗
Phenotype and genotype expression in pseudohomozygous factor VLEIDEN : the need for phenotype analysis.
The presence of a DNA mutation is frequently used to define a disease or a risk state. Because DNA typing has become easy and convenient in contrast to protein characterization, it is generally assumed that a mutation if present (or not) at the DNA level will be also present (or not) in the corresponding protein. However, discrepancies between phenotype and genotype can occur. A point mutation in the coagulation factor V gene (G1691-->A, resulting in an Arg506-->Gln amino acid substitution in the factor V molecule [factor VLEIDEN], leading to activated protein C resistance) is the most common genetic risk factor for familial thrombophilia. A pseudohomozygous factor VLEIDEN phenotype would occur if a heterozygous individual for factor VLEIDEN also did not express the "normal" (non-Leiden) factor V allele. However, to date, no data have been available to confirm the presence of only the factor VLEIDEN form in the plasma of these individuals. Platelet mRNA from 2 presumed pseudohomozygous patients and their family members was isolated, the amplified partial cDNAs were sequenced or restricted, and the allelic bands were quantified. Both patients were found to be heterozygous for the G1691-->A substitution at both the DNA and mRNA levels. The presence of either the normal or mutated form of factor V in the patients' plasmas was investigated using a monoclonal antibody to factor V that recognizes an epitope located between residues 307 and 506 of the factor Va heavy chain. No normal factor V could be detected in the plasmas of the 2 propositi. The present data demonstrate absence of a correlation between genotype at position 1691 (at the DNA and mRNA levels) and the corresponding phenotype data found in the plasmas of patients with pseudohomozygous factor VLEIDEN. Overall, these data suggest the existence of heterogeneous genetic "lesions," which interfere with factor V expression, processing, secretion, and/or stability. Because the presence of the factor VLEIDEN molecule in plasma is directly related to pathology, identification and quantification of the circulating forms of factor V in plasma may be required for the diagnosis of individuals with activated protein C resistance.
Adult↗
Incidence of venous thromboembolism in families with inherited thrombophilia.
The risk of spontaneous or risk-period related venous thromboembolism in family members of symptomatic carriers of antithrombin (AT), protein C (PC) or protein S (PS) defects, as well as of the Factor V Leiden mutation is still undefined. We performed a retrospective cohort study in family members (n = 793) of unselected patients with a documented venous thromboembolism and one of these deficiencies to make an estimate of this risk. The annual incidences of total and spontaneous venous thromboembolic events in carriers of AT, PC or PS defects (n = 181) were 1.01% and 0.40%, respectively, as compared to 0.10% and 0.04% in non-carriers, respectively (relative risks both 10.6). In carriers of Factor V Leiden (n = 224), the annual incidences of total and spontaneous venous thromboembolism were 0.28% and 0.11%, respectively, as compared to 0.09% and 0.04% in non-carriers, respectively (relative risks 2.8 and 2.5). Additional risk factors (immobilisation, surgery and trauma: oral contraceptive use; and pregnancy/ post-partum) increased the risk of thrombosis in carriers of AT, PC and PS defects as compared to non-carriers (relative risks 8.3, 6.4 and 8.2, respectively). Oral contraceptive use and pregnancy/ post-partum period increased the risk of thrombosis in carriers of Factor V Leiden to 3.3-fold and 4.2-fold, respectively, whereas other risk factors had only a minor effect. These data lend some support to the practice of screening family members of symptomatic carriers of a AT, PC and PS deficiency. For family members of symptomatic carriers of Factor V Leiden, screening does not seem to be justified except for women in fertile age.
Adolescent↗
Post-DDAVP thrombocytopenia in type 2B von Willebrand disease is not associated with platelet consumption: failure to demonstrate glycocalicin increase or platelet activation.
Thrombocytopenia is frequently reported in type 2B von Willebrand disease (vWD), and thought to be related to the abnormally high affinity of 2B von Willebrand factor (vWF) for platelet GPIb-IX. To gain an insight into the nature of this thrombocytopenia, we measured plasma glycocalicin (GC) levels (as a marker of platelet turnover), and platelet surface expression of the alpha granule protein P-selectin (as a marker of platelet activation) in 9 patients with type 2B vWD before, and in 4 patients also following the infusion of 1-desamino-8-d-arginine vasopressin (DDAVP). Three patients presented a persistent decrease of platelet counts in the resting condition. GC levels were within the normal range, regardless of the platelet counts, in all but one patient who presented, on the other hand, a normal platelet count. Moreover, platelets expressed normal amounts of P-selectin on their surface, regardless of platelet counts. These findings suggest that the thrombocytopenia observed in type 2B vWD is not due to platelet activation and subsequent consumption in circulation. Despite a significant, albeit transient, decrease in platelet count, DDAVP did not induce an increase in plasma GC levels, nor enhance P-selectin expression. These observations indicate that the acute post-DDAVP thrombocytopenia in type 2B vWD is not related to platelet activation and consumption. We advance that the post-DDAVP 2B vWF is hemostatically more active, and able to induce agglutination but not aggregation of circulating platelets. This would explain both the prompt recovery of basal platelet counts after the post-DDAVP decrease, and the lack of reported thrombotic complications in this disorder. Therefore, even though 2B vWF is characterized by an enhanced affinity for the platelet surface, its binding to platelet GPIb-IX in the soluble phase is not able to induce true platelet aggregation: vWF thus appears to be mainly an adhesive protein, rather than an aggregating agent.
Adult↗
D-dimer testing as an adjunct to ultrasonography in patients with clinically suspected deep vein thrombosis: prospective cohort study. The Multicentre Italian D-dimer Ultrasound Study Investigators Group.
OBJECTIVE: To investigate the efficacy of using a rapid plasma D-dimer test as an adjunct to compression ultrasound for diagnosing clinically suspected deep vein thrombosis. DESIGN: D-dimer concentrations were determined in all patients with a normal ultrasonogram at presentation. Repeat ultrasonography was performed 1 week later only in patients with abnormal D-dimer test results. MAIN OUTCOME AND MEASURES: Patients with normal ultrasonograms were not treated with anticoagulants and were followed for 3 months for thromboembolic complications. SETTING: University research and affiliated centres. SUBJECTS: 946 patients with clinically suspected deep vein thrombosis. RESULTS: Ultrasonograms were abnormal at presentation in 260 (27.5%) patients. Of the remaining 686 patients tested for D-dimer, 88 (12.8%) had abnormal concentrations. During follow up venous thromboembolic complications occurred in one of the 598 patients who were not treated with anticoagulants and who had an initial normal ultrasonogram and D-dimer concentration, whereas thromboembolic complications occurred in two of the 83 untreated patients who had abnormal D-dimer concentrations but a normal repeat ultrasonogram. The cumulative incidence of venous thromboembolic complications during follow up was 0.4% (95% confidence interval 0% to 0.9%). The rapid plasma D-dimer test used as an adjunct to compression ultrasonography resulted in a reduction in the mean number of repeat ultrasound examinations and additional hospital visits from 0.7 to 0.1 per patient. CONCLUSIONS: Testing for D-dimer as an adjunct to a normal baseline ultrasound examination decreased the number of subsequent ultrasound examinations considerably without any increased risk of venous thromboembolic complications in patients not receiving anticoagulants. The use of ultrasound and testing for D-dimer enabled treatment decisions to be made at the time of presentation in most patients.
Biomarkers↗
Ultrasonography of contralateral veins in patients with unilateral deep-vein thrombosis.
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Female↗
Use of an algorithm for administering subcutaneous heparin in the treatment of deep venous thrombosis.
BACKGROUND: Despite the widespread use of subcutaneous heparin in the initial treatment of deep venous thrombosis, there are no guidelines for achieving adequate anticoagulation with this drug. OBJECTIVE: To implement a weight-based algorithm for the administration of subcutaneous unfractionated heparin after an intravenous loading dose. DESIGN: Prospective cohort study. SETTING: University hospital. PARTICIPANTS: 70 outpatients with proximal venous thrombosis. INTERVENTION: An intravenous bolus of heparin followed by a subcutaneous injection of heparin in doses adjusted for body weight. Subsequent adjustments of the subcutaneous heparin dose were scheduled twice daily according to the algorithm; the activated partial thromboplastin time (aPTT) was measured in the mid-interval (target range, 50 to 90 seconds). RESULTS: The therapeutic threshold aPTT (> or = 50 seconds) was achieved in 61 patients (87%) within 24 hours and in 69 patients (99%) within 48 hours. In 7 patients (10%), a supratherapeutic aPTT lasted more than 12 hours. No major bleeding episodes or cases of heparin-induced thrombocytopenia were seen. Three patients (4.3% [95% CI, 0.9% to 12.0%]) had recurrent thromboembolism during 3 months of follow-up. CONCLUSION: The administration of subcutaneous heparin according to a weight-based algorithm allows the rapid achievement of effective and safe anticoagulation in patients with deep venous thrombosis.
Aged↗
Platelet-derived factor Va/Va Leiden cofactor activities are sustained on the surface of activated platelets despite the presence of activated protein C.
We investigated the role of the thrombin-activated platelet in modulating the rate and extent of activated protein C (APC)-catalyzed inactivation of platelet-derived factor Va and factor VaLeiden. Platelet-derived factor Va and factor VaLeiden were inactivated by APC at near identical rates; however, complete inactivation of the cofactors was never achieved. Greater residual cofactor activity remained when using thrombin-activated platelets compared with that observed with synthetic phospholipid vesicles and platelet-derived microparticles, suggesting that thrombin-activated platelets protect the cofactors from APC-catalyzed inactivation. This apparent protection was not due to (1) an insufficient number of membrane binding sites for APC or factor Va; (2) the destruction of these sites; or (3) the presence of a platelet-associated APC inhibitor. Results from a plasma-based clotting assay (with or without APC) with platelets or PCPS vesicles added to induce clot formation indicated that, even in the presence of high concentrations of APC, platelets offered protection of the cofactor by delaying cleavage at Arg506. This resulted in incomplete proteolysis of the heavy chain, suggesting that platelets can also protect plasma-derived factor Va from APC-catalyzed inactivation. However, additional experiments indicated that the plasma-derived cofactor, bound to thrombin-activated platelets, was completely inactivated by APC, suggesting that the plasma and platelet-derived cofactor pools represent different substrates for APC. Collectively, these results indicate that platelets sustain procoagulant events by providing a membrane surface that delays cofactor inactivation and by releasing a cofactor molecule that displays an APC resistant phenotype. Thus, at sites of arterial injury, the factor VLeiden mutation may not as readily predict arterial thrombosis, because the normal and variant platelet-derived cofactors are equally resistant to APC at the activated platelet surface.
Blood Platelets↗
Platelet count, anti-heparin/platelet factor 4 antibodies and tissue factor pathway inhibitor plasma antigen level in chronic dialysis.
We studied 50 chronic dialysis patients with end-stage renal disease. Mean platelet count was within normal limits. An inverse linear correlation was observed between pre-dialysis platelet count and serum creatinine (r=0.304, p=0.038). Dialysis caused a decrease in platelet count (216+/-80x10(9)/L, pre; 198+/-68, post; p=0.0001), and the higher the pre-dialysis platelet count, the greater the decrease (r=0.623, p=0.0001). Post-dialysis triglyceride decreased (1.67+/-1.27 mmol/L, pre; 1.23+/-0.96, post; p=0.0001). Tissue factor pathway inhibitor (TFPI) antigen plasma level was higher in uremic patients than in controls (114+/-42 ng/ml vs. 64+/-12, p=0.0001). TFPI increased 2.3 times following dialysis and such an increase was directly correlated with post-dialysis plasma heparin concentration (r=0.571, p=0.0002) and inversely correlated with post-dialysis triglyceride variation (r=0.407, p=0.005). Six of fifty patients (12%) had anti-heparin/platelet factor 4 antibodies (Hab), 3 IgG, and 3 IgM. Female sex and the use of cuprophane membranes were more frequent among Hab-positive patients (p=0.0001), while a lower percentage of them were on anti-aggregating drugs as compared to Hab-negative patients (p=0.002). Only one Hab-positive patient was slightly thrombocytopenic and none showed bleeding or thrombotic manifestations. Serum albumin and y globulin decreased following dialysis in Hab-positive patients, while the opposite was seen in those Hab-negative (-2.47+/-1.72 g/L, vs. 0.21+/-1.77, p=0.001 and -0.48+/-0.60 g/L vs. 0.64+/-0.97, p=0.007, respectively). In vivo factors other than Hab are involved in the development of heparin-induced thrombocytopenia. Besides a blunted immunological response, increased levels of TFPI, the use of anti-aggregating drugs, and the observed behavior of serum proteins might play a role in this regard.
Adult↗
Hemorrhagic and thrombotic disorders due to factor V deficiencies and abnormalities: an updated classification.
The recent description of a factor V abnormality (factor V Leiden) associated with an increased incidence of thrombosis has considerably increased interest in this clotting factor. The discovery of this new clinical entity indicated the need for an updated classification of factor V defects. These should be divided into hemorrhagic and thrombotic disorders. A proper classification of hemorrhagic disorders should include: 1) homozygous and heterozygous 'true' factor V deficiency; and 2) combined factor V and factor VIII deficiencies. The latter should be subdivided in Type I (association type) and Type II (common defect). A suitable classification of the thrombotic factor V defects should include: 1) homozygous and heterozygous factor V Leiden; and 2) combined heterozygous factor V Leiden and heterozygous 'true' factor V deficiency. The presence of thrombosis in these latter patients, often as severe as those seen in homozygous patients with activated protein C (APC) resistance, allows important considerations on the functions of factor V. It would seem that half the normal level of factor V activity and antigen is unable to protect against thrombosis in patients with heterozygous APC resistance. An accurate evaluation of factor V activity and antigen is indicated in all patients with suspected factor V defects. The first suspicion may be obtained by the presence of a mild prolongation of prothrombin time and of partial thromboplastin time. The suspicion should then be immediately confirmed by specific factor V activity and antigen assays. This approach is of great importance even for the presumptive diagnosis of pseudohomozygosis for APC resistance. In fact, in these cases, factor V activity is about 50% of normal, whereas factor V antigen is 100% of normal. In heterozygous 'true' factor V deficiency both activity and antigen are about 50% of normal.
Clinical Laboratory Techniques↗
Type 2N von Willebrand disease due to Arg91Gln substitution and a cytosine deletion in exon 18 of the von Willebrand factor gene.
Two members of a family previously classified as type 1 von Willebrand disease (VWD), showed a quantitative defect in von Willebrand factor (VWF) antigen and ristocetin cofactor activity and an abnormal capacity of VWF to bind FVIII. Sequencing of the VWF gene region coding for the FVIII binding domain revealed the most frequent type 2N mutation: a single nucleotide change (G2811A) in exon 20, resulting in substitution of glutamine (Gln) for arginine (Arg) 91 in the mature VWF protein in one allele. The other allele contained a cytosine deletion (2680delC) in exon 18, introducing a premature stop codon at position 79 (Val79X) which produced a quantitative defect in VWF levels. The Arg91Gln defect is usually not evident in heterozygotes; however, in these patients it was expressed due to the lack of VWF production from the other allele. This is the first report of type 2N VWD in Italy.
Arginine↗
Two novel mutations (Pro864His, Val867Glu) causing type 2A von Willebrand disease and affecting a single restriction site in exon 28.
We detected two transversions in two unrelated Italian patients with type 2A von Willebrand disease (VWD): a C to A at nucleotide 8821 and a T to A at nucleotide 8830, resulting in the missense mutations Pro864His and Val867Glu respectively. Both mutations were in the heterozygous form and abolished the BstXI restriction site in exon 28 of the VWF gene. In both mutations plasma VWF multimer pattern improved by antiproteases. Moreover, DDAVP normalized plasma VWF multimers in the Pro864His patient, especially when protease inhibitors were present. These new mutations appear to be of the 2A VWD subtype due to the increased susceptibility to proteases.
Adult↗
Prothrombin antigen levels in symptomatic and asymptomatic carriers of the 20210A prothrombin variant.
A recently discovered variant in the prothrombin gene (20210A) has been found in approximately 5-10% of patients with venous thromboembolism. It has been shown that patients with this variant present with high levels of prothrombin in plasma and this is maintained to be the most likely mechanism by which the risk of thrombosis is increased. We have evaluated prothrombin antigen levels in 50 carriers of the 20210A allele and compared with non-carriers. 327 subjects were subdivided according to deficiency status and previous thrombosis. 30 symptomatic and 20 asymptomatic carriers had increased mean prothrombin levels as compared to symptomatic (n=178) or asymptomatic (n=99) non-carriers. The percentage of subjects with prothrombin levels above cut-off values of 1.15u/ml or 1.30u/ml was significantly higher in carriers of the prothrombin variant as compared to non-carriers, regardless of a previous thrombosis. However, among non-carriers the percentage of those with prothrombin levels above cut-off values was significantly higher in the group of symptomatic as compared to asymptomatic individuals. In conclusion, increased prothrombin antigen levels, as detected by a specific ELISA, were found among 50 symptomatic and asymptomatic carriers of the 20210A prothrombin variant as well as among a large group of symptomatic non-carriers. The data are in agreement with those found by using functional tests for the determination of prothrombin levels in these patients.
Adult↗
Autoimmune thrombocytopenia (AITP) and thyroid autoimmune disease (TAD): overlapping syndromes?
The pathogenesis of thrombocytopenia associated with TAD and the occurrence of overlapping traits between TAD and AITP are still a matter of debate. For this reason, we investigated for the presence and specificity of platelet and thyroid autoantibodies in 18 TAD patients with thrombocytopenia, 19 TAD patients without thrombocytopenia and in 22 patients with primary AITP without clinical signs of TAD. Platelet-associated IgG and/or specific circulating platelet autoantibodies were detected in 83% of patients with TAD and thrombocytopenia, in 10% of patients with TAD without thrombocytopenia and in 86% of patients with primary AITP. The reactivity of serum autoantibodies, assayed by MoAb immobilization of platelet antigens (MAIPA), was directed against platelet glycoproteins Ib and/or IIb/IIIa in 50% of the patients with TAD and thrombocytopenia, as in 46% of the patients with primary AITP. Thyroid autoantibodies were found in 89% of patients with TAD and thrombocytopenia, in 95% of patients with TAD without thrombocytopenia, and in 18% of patients with primary AITP. Thyrotropin (TSH) levels determined in three of four AITP patients with thyroid autoantibodies revealed a subclinical hyperthyroidism in one patient. The present study supports the autoimmune aetiology of thrombocytopenia associated with TAD, since the prevalence and specificity of platelet autoantibodies are similar in TAD and primary AITP. The results indicate also that there exists an overlap between thyroid and platelet autoimmunity with or without clinical manifestations.
Adult↗
A simple clinical model for the diagnosis of deep-vein thrombosis combined with impedance plethysmography: potential for an improvement in the diagnostic process.
OBJECTIVES: We recently demonstrated the utility of a clinical model combined with ultrasonography to assist the diagnostic approach in patients with suspected deep-vein thrombosis (DVT). In this study we also sought to demonstrate that the model is useful with impedance plethysmography, a less accurate and less utilized diagnostic test. The original clinical model is slightly cumbersome to use; thus at the completion of the study we attempted to develop a simpler scoring system with a goal of maintaining accuracy. DESIGN: An open, nonrandomized, multicentre trial. SETTING: Three centres, two in Canada, and one in Italy. SUBJECTS: Ambulatory patients with suspected deep-vein thrombosis. INTERVENTIONS: All patients were assessed clinically to determine the probability for deep-vein thrombosis prior to performing impedance plethysmography and venography. We compared the accuracy of impedance plethysmography between the three pretest probability categories of high, moderate and low. All of the above were performed and interpreted by independent observers. When the study was completed, we revised the clinical model by first performing a simple regression analysis then a multiple logistic regression analysis; a scoring system was devised using the latter. RESULTS: Impedance plethysmography is significantly more sensitive and less specific for all DVT in patients with high pretest probability for deep-vein thrombosis (P = 0.001). The post- test probability (positive predictive value) for deep-vein thrombosis with an abnormal impedance plethysmography result was significantly different (P = 0.0001) between the three pretest probability categories. Multiple regression analysis has provided a new model with only nine variables and a simple scoring system. The retrospective application of the revised clinical model, which is simpler to use, suggests it will provide similar results as the original clinical model when combined with impedance plethysmography. The combination of impedance plethysmography and the clinical model suggests patients are likely to have false positive results if they have a low or moderate pretest probability for deep-vein thrombosis and false negative results if the pretest probability is high. The combination of a low pretest probability and a normal impedance plethysmography result may exclude the need for serial testing, and represented more than 50% of our patient population. CONCLUSIONS: The use of the clinical model in conjunction with impedance plethysmography would decrease the number of false positive and negative diagnoses and could markedly decrease the need for serial impedance plethysmography. Combining the clinical model with impedance plethysmography could overcome the fact that impedance plethysmography is clearly less accurate than venous ultrasound imaging. The use of the revised clinical model may increase acceptability and utility, but prospective testing is required before widespread use.
Diagnosis, Differential↗
Acute coronary disease in essential thrombocythemia and polycythemia vera.
OBJECTIVES: The aim of this study is to report our experience on myocardial infarction (MI) in patients with essential thrombocythemia (ET) and polycythemia vera (PV). DESIGN: Patients with PV and ET consecutively diagnosed and followed in authors' Department between 1 July 1986 and 30 June 1996. SUBJECTS: Over the past 10 years we have followed 170 patients with ET and 149 with PV, diagnosed according to the Polycythemia Vera Study Group (PVSG) criteria. The patients were divided into 3 groups on the basis of the age at diagnosis (group A < 40, B 41-65, C > 65 years). INTERVENTIONS: In all patients with PV phlebotomies and/or myelosuppressive therapy were used to keep haematocrit level lower than 45%. Hydroxyurea was given to patients with ET with a positive history for major vascular complications or with an extreme thrombocytosis. Aspirin therapy (ASA) (100 mg per day) was administered in patients with microvascular disturbances or previous thrombosis (in patients with PV also in the presence of atherosclerotic risk factors). MAIN OUTCOME MEASURES: Frequency of MI in patients with ET and PV with and without ASA therapy. RESULTS: 9.4% of patients with ET and 11.4% of those with PV had MI. 17.6% of patients with PV were younger than 40 years at the moment of MI in contrast to 0% of those with ET. 75% of patients with ET and 70.6% of those with PV with MI had atherosclerotic risk factors such as smoking, hypertension, diabetes, dyslipidaemia. All patients with MI received ASA 100 mg daily after thrombosis and four of the ET group developed a transient ischaemic attack (TIA) afterwards. Four subjects with PV during the follow-up had TIAs and two peripheral arteriopathy in spite of ASA treatment. CONCLUSIONS: MI is less common in patients with ET younger than 40 years than in older patients. Association of MI and cardiovascular risk factors is frequent in patients with ET and PV. A low dose of ASA could be able to reduce the number of coronary thrombosis without increasing bleeding complications in patients with elevated platelet count and common atherosclerotic risk factors. However, a larger population must be evaluated to confirm our hypothesis.
Adult↗