Primary thrombophilia in Mexico. V. A comprehensive prospective study indicates that most cases are multifactorial

Factor V Leiden-independent activated protein C resistance: Communication from the plasma coagulation inhibitors subcommittee of the International Society on Thrombosis and Haemostasis Scientific and Standardisation Committee

Activated protein C resistance (APC-R) due to the single-nucleotide polymorphism factor V Leiden (FVL) is the most common cause of hereditary thrombophilia. It is found predominantly in Caucasians and is uncommon or absent in other populations. Although FVL is responsible for >90% of cases of hereditary APC-R, a number of other F5 variants that also confer various degrees of APC-R and thrombotic risk have been described. Acquired APC-R due to increased levels of coagulation factors, reduced levels of inhibitors, or the presence of autoantibodies occurs in a variety of conditions and is an independent risk factor for thrombosis. It is common for thrombophilia screening protocols to restrict assessment for APC-R to demonstrating the presence or absence of FVL. The aim of this Scientific and Standardisation Committee communication is to detail the causes of FVL-independent APC-R to widen the diagnostic net, particularly in situations in which in vitro APC-R is encountered in the absence of FVL. Predilution clotting assays are not FVL specific and are used to detect clinically significant F5 variants conferring APC-R, whereas different forms of acquired APC-R are preferentially detected using the classical activated partial thromboplastin time-based APC-R assay without predilution and/or endogenous thrombin potential APC-R assays. Resource-specific recommendations are given to guide the detection of FVL-independent APC-R.

Primary Thrombophilia XVII: A Narrative Review of Sticky Platelet Syndrome in México

Sticky Platelet Syndrome (SPS) is a disorder characterized by platelet hyperaggregability, diagnosed by studying in vitro platelet aggregation with ADP and epinephrine. It is the second most common cause of thrombophilia in Mexican Mestizos and manifests as an autosomal dominant trait which, combined with other coagulopathies, contributes significantly to the morbidity and mortality of patients with primary thrombophilia. It is easily treatable with antiplatelet drugs; however, the methods for diagnosis are not readily available in all clinical laboratories and the disorder is often overlooked by most clinicians. Herein, we present the results of more than 20 years of Mexican experience with the study of SPS in a Mestizo population.

A new decade awaits sticky platelet syndrome: where are we now, how do we manage and what are the complications?

INTRODUCTION

Sticky platelet syndrome is a less known platelet function disorder with a familiar occurrence and likely genetic background. Clinically, it is characterized by an increased risk of venous and arterial thromboembolic events and obstetric placenta-mediated complications. The increased aggregation after low-dose ADP and/or epinephrine is its distinctive laboratory feature. Though described for almost 40 years, several issues regarding its etiology, involved pathomechanisms, genetic background, optimal diagnostic and treatment approach remain controversial.

AREAS COVERED

The work aims to summarize published studies, the actual definition of the syndrome, and point out its drawbacks. A literature search on Medline, Embase, and archives from EHA congresses was performed (terms: 'sticky platelet syndrome' - 'platelet hyperreactivity' - 'platelet hyperaggregability'). The authors added in their unpublished data. The introductory overview of the present understanding is followed by the discussion of the pathophysiologic, diagnostic, and therapeutic problems.

EXPERT OPINION

Despite the growing evidence provided by case reports and series, the lack of robust studies limits the decision-making on diagnostics and management. The diagnostic issues, particularly the standardization of light transmission aggregometry, represent the crucial problem for the broader acceptance of the syndrome.

Primary Thrombophilia XVI: A Look at the Genotype of the Sticky Platelet Syndrome Phenotype

The sticky platelet syndrome (SPS) was described by Mammen in 1983. Since then, scientists in several countries have identified the condition and published cases or series of patients, thus enabling the description of the prevalence of the inherited condition, its salient clinical features, and the treatment of the disease. The diagnosis of the SPS phenotype requires fresh blood samples and special equipment which is not available in all coagulation laboratories. In the era of molecular biology, up to now it has not been possible to define a clear association of the SPS phenotype with a specific molecular marker. Some molecular changes which have been described in platelet proteins in some persons with the phenotype of the SPS are here discussed. Nowadays, the SPS phenotype may be considered as a risk factor for thrombosis and most cases of the SPS developing vaso-occlussive episodes are the result of its coexistence with other thrombosis-prone conditions, some of the inherited and some of them acquired, thus leading to the concept of multifactorial thrombophilia. Ignoring all these evidence-based concepts is inappropriate, same as stating that the SPS is a nonentity simply because not all laboratories are endowed with adequate equipment to support the diagnosis.

High Prevalence of Sticky Platelet Syndrome in Patients with Infertility and Pregnancy Loss

Platelet hyperaggregability, known as sticky platelet syndrome (SPS), is a prothrombotic disorder that has been increasingly associated with pregnancy loss. In this retrospective study, we aimed to investigate the clinical and diagnostic relevance of SPS in 208 patients with infertility and unexplained pregnancy loss history. We studied 208 patients that had been referred to undergo a dose-dependent platelet aggregation response to adenosine diphosphate and epinephrine using light transmission aggregometry modified by Mammen during an 11-year period. Patients’ platelet aggregation response was compared with platelet function in 29 female healthy controls of fertile age with no previous history of pregnancy loss. We found a prevalence of SPS type II (33.2%) in 208 female patients with infertility and pregnancy loss. ∆-epinephrine-induced platelet aggregation in patients with SPS was significantly decreased (median 7% and range −21 to 43%) compared to patients without SPS (median 59%, range 7–88% and p < 0.0001) and healthy controls (median 57%, range 8–106% and p < 0.0001). The optimum SPS-diagnostic cutoff value for ∆-epinephrine aggregation was ≤32% (sensitivity 95.7%, specificity 95.2%). SPS patients with low-dose acetylsalicylic acid (ASA) therapy (n = 56) showed improved pregnancy outcome (32 pregnancies; live births n = 18 (56%)) compared to SPS patients without low-dose ASA (n = 13) (3 pregnancies; live births n = 1 (33%)). Our study demonstrates the clinical and diagnostic relevance of platelet hyperaggregation in women with infertility and pregnancy loss history. Further studies should investigate the potential of SPS as a novel decisional tool with both diagnostic and clinical implications in infertility and pregnancy loss.

Primary Thrombophilia in Mexico XIII: Localization of the Thrombotic Events in Mexican Mestizos With the Sticky Platelet Syndrome

The sticky platelet syndrome (SPS) is a common cause of both arterial and venous thrombosis, being a dominant autosomal disease with qualitative platelet alterations and familial occurrence. It is characterized by platelet hyperreactivity with increased platelet aggregability in response to low concentrations of platelet agonists: epinephrine, adenosine diphosphate, or both. The clinical manifestations involve venous or arterial thrombosis, recurrent pregnancy loss, and fetal growth retardation. To analyze the localization of the thrombotic episodes in a cohort of Mexican mestizo patients with SPS. Between 1992 and 2016, 86 Mexican mestizo patients with SPS as the single thrombophilic condition were prospectively identified; all of them had a history of thrombosis. There were 15 males and 71 females. The thrombotic episodes were arterial in 26 cases and venous in 60 (70%). Arterial thrombosis was mainly pulmonary thromboembolism, whereas venous thromboses were identified most frequently in the lower limbs. Mexican mestizo population with SPS is mainly female; the type I of the condition is the most frequent; both arterial and venous thrombosis can occur, and they are mainly pulmonary embolism and lower limbs venous thrombosis, respectively.

High prevalence of factor V Leiden and prothrombin G20101A mutations in Kashmiri patients with venous thromboembolism

AIM

The genetic variants of the factor V (G1691A), prothrombin (G20210A) and MTHFR (C677T) genes have been widely implicated as inherited risk factors for developing venous thrombosis. This study was undertaken to reveal the frequency of these mutations in Kashmiri patients with venous thromboembolism.

METHODOLOGY

A case-control study was designed with 250 VTE patients and 250 healthy controls. The mutations were analysed using ARMS-PCR and PCR-RFLP approach.

RESULT

The factor V Leiden G1691A mutation was found in 17/250 (6.8%) VTE patients and prothrombin G20210A mutation was found in 7/250 (2.8%) VTE patients while no mutation was found in any of the healthy controls. Both the mutations were found to be significantly associated with the increased risk of VTE (p = 0.0001 and 0.0150 respectively) while no association of VTE risk with MTHFR C677T polymorphism was found (p = 0.53).

CONCLUSION

The increased frequency of factor V Leiden G1691A and prothrombin G20210A mutation in VTE patients indicates a significant role of these mutations in the development of VTE in our population. We therefore suggest the routine screening of these two mutations as thrombophilic markers in Kashmiri patients with venous thromboembolism.

Primary Thrombophilia in Mexico XII: Miscarriages Are More Frequent in People with Sticky Platelet Syndrome

Objective:

Sticky platelet syndrome (SPS) is an inherited condition that leads to arterial and venous thrombosis. There is scant information about the association between SPS and obstetric complications. This study aimed to assess the relationship between SPS and fetal loss at a single institution.

Materials and Methods:

The obstetric histories of all consecutive female patients prospectively studied in a 324-month period at a single institution with a history of thrombosis and a clinical marker of primary thrombophilia were reviewed.

Results:

Between 1989 and 2016, 268 consecutive patients with a clinical marker of primary thrombophilia and a history of arterial or venous thrombosis were studied; of these, 108 were female patients. Within this subset of thrombophilic females, 77 (71%) had been pregnant at some point. Twenty-eight of these 77 patients (37%) had had a spontaneous abortion and 24 of those (86%) were found to have SPS. On the other hand, in a subset of 73 female patients with SPS who had been pregnant, 32% had miscarriages. These figures are significantly higher than the prevalence of spontaneous abortions in the general Mexican population of pregnant women, which is 12%-13% (chi-square: 7.47; p=0.0063). Accordingly, the relative risk of having a miscarriage is 2.66 times higher in female patients with SPS than in the general population (p=0.0014).

Conclusion:

In Mexico, female patients with SPS experience significantly more spontaneous abortions than the general population. Since the treatment of SPS is simple and effective and could in turn prevent adverse obstetric outcomes, its investigation in women treated for obstetric complications may be useful and deserves further research.

Sticky platelet syndrome: an important cause of life-threatening thrombotic complications

Sticky platelet syndrome (SPS) is a prothrombotic thrombocytopathy with familial occurrence, characterized by hyperaggregability of platelets in response to adenosine diphosphate (ADP), epinephrine (EPI) or both. The syndrome has been identified in approximately 21% of unexplained arterial thrombotic episodes, regarded to be the most common thrombophilia in arterial thrombosis and 13.2% of unexplained venous thromboembolism (VTE). The relatively young age at the first manifestation, relation to fertility and pregnancy, seriousness of the symptoms, easy and effective management of the disorder indicate to the necessity to take it into account in the differential diagnosis of the underlying cause of the thrombotic event. As the various localizations of the thrombosis in SPS have been reported, its management often requires a multidisciplinary approach. This review deals with the clinical aspects of thrombophilia, its etiopathogenesis, diagnosis as well as novel advances in the treatment and outlines the challenges for the further research.

Thrombin generation and international normalized ratio in inherited thrombophilia patients receiving thromboprophylactic therapy

BACKGROUND

Thrombin generation assay (TGA) is useful as a global functional test for assessing bleeding or thrombotic risk and its modification with therapy. We investigated TGA to assess anticoagulation status compared with the international normalized ratio (INR) system in patients with primary thrombophilia receiving and not undergoing thromboprophylaxis.

MATERIALS AND METHODS

We studied 50 patients with at least one thrombotic event and a confirmed diagnosis of inherited thrombophilia. Thrombin generation was measured in platelet-poor plasma by calibrated automated thrombography (CAT).

RESULTS

Patients in optimal anticoagulation (INR: 2.0-3.0) showed an endogenous thrombin potential (ETP) of 14-56% of normal and a peak of 18-55% of normal. A significant inverse relationship between INR and thrombin generation parameters (ETP, peak and velocity index) and a linear correlation for lag time was found in patients treated with vitamin-K antagonists (VKA). Receiver-operating characteristics (ROC) analysis showed that the optimal cutoff for ETP was 1600.2 nM · min (111.6% of normal, with a sensitivity of 96.6% and a specificity of 92.9%) and for the peak was 298.3 nM (112.1% of normal, with a sensitivity of 96.4% and a specificity of 100%). According to this analysis, ETP was able to identify patients with increased thrombotic and hemorrhagic risk, correlating with severe clinical complications.

CONCLUSION

TGA showed excellent sensitivity and specificity for assessing anticoagulation status in patients with primary thrombophilia receiving VKA, with significant advantages with regard to INR. Clinical data strongly support ETP as a valuable indicator of thrombotic or hemorrhagic risk in patients receiving or not receiving thromboprophylaxis.

Portal vein thrombosis with protein C-S deficiency in a non-cirrhotic patient

There are several conditions that can lead to portal vein thrombosis (PVT), including including infection, malignancies, and coagulation disorders. Anew condition of interest is protein C and S deficiencies, associated with hypercoagulation and recurrent venous thromboembolism. We report the case of a non-cirrhotic 63-year-old male diagnosed with acute superior mesenteric vein thrombosis and PVT and combined deficiencies in proteins C and S, recanalized by short-term low molecular heparin plus oral warfarin therapy.

Primary Thrombophilia in México X

Introduction:

The sticky platelet syndrome (SPS) is a common cause of thrombosis. There are no prospective studies concerning treatment.

Objective:

To analyze changes in platelet hyperaggregability of patients with SPS who were given antiplatelet drugs and to assess its association with rethrombosis.

Methods:

A total of 55 patients with a history of thrombosis and SPS phenotype were prospectively studied before and after treatment with aspirin and/or clopidogrel.

Results:

Patients were followed for 1 to 129 months, median 13. Of 55 patients, 40 received aspirin, 13 received aspirin + clopidogrel, and 2 received only clopidogrel. The platelet aggregation response to adenosine diphosphate and epinephrine significantly diminished after treatment, and only 2 patients developed rethrombosis 52 and 129 months after starting therapy, with the freedom from rethrombosis rate of the patients being 96.4% at 129 months.

Conclusion:

Using antiplatelet drugs, the platelet hyperreactivity of patients with the SPS phenotype was reverted; and this translated into a substantial decrease in the rethrombosis rate.

Platelet Hyperaggregability is Highly Prevalent in Patients With Chronic Kidney Disease

Background:

Platelet hyperaggregation is known to be associated with arterial and venous thromboembolic events. The prevalence of platelet hyperaggregation in patients with chronic kidney disease (CKD) has not been described to date.

Methods:

Platelet hyperaggregation in patients with renal disease was defined by comparison of platelet aggregation patterns to non-CKD patients without thromboembolic disorders and healthy controls.

Results:

Among the 30 hemodialysis patients and 34 renal transplant recipients, 20 (67%) and 28 (82%) showed significantly decreased median Δ-epinephrine aggregation and increased 0.5 mol/L epinephrine response (65% and 54%) compared to healthy controls and non-CKD patients. In concordance to the laboratory finding of platelet hyperaggregability, renal transplant recipients showed a high rate of thromboembolic events (normal platelet aggregation: 0 events and platelet hyperaggregation: 30 events in 13 of 28 patients).

Conclusions:

Patients with CKD exhibit a hitherto unappreciated high prevalence of platelet hyperaggregability indicating sticky platelet syndrome. Laboratory testing of platelet hyperaggregability may supplement the assessment of thromboembolic complications in patients with CKD.

Sticky platelet syndrome in patients with uninduced venous thrombosis

OBJECTIVE

Sticky platelet syndrome (SPS) is a common autosomal dominant inherited platelet disorder. SPS is characterized by platelet hyperreactivity and is associated with arterial and venous thrombosis. The aim of this study was to determine the role of SPS in patients with uninduced venous thrombosis.

MATERIAL AND METHODS

The study included 28 patients (15 male and 13 female) with uninduced venous thrombosis. SPS was defined according to Mammen's aggregation method, which is described in detail elsewhere.

RESULTS

According to the defined ranges for platelet hyperreactivity, 3 (50%) patients, 2 (33%), and 1 (17%) (n =6 [21%]) with a confirmed diagnosis were classified as type II, I, and III SPS, respectively. In 1 patient SPS was the only hereditary abnormality noted. The other 5 patients carried other inherited coagulation defects, in addition to SPS.

CONCLUSION

The present findings indicate that the prevalence of SPS was 21% in the patients with uninduced venous thrombosis. We therefore suggest that SPS should be considered in the differential diagnosis of such cases.

CONFLICT OF INTEREST

None declared.

Primary thrombophilia in Mexico IX

Introduction:

The sticky platelet syndrome (SPS) seems to be a common cause of thrombosis, although no molecular substrate to explain platelet hyperaggregability has been found.

Objective:

To analyze an association between the SPS phenotype and the platelet glycoprotein (GP) IIIa PLA1/A2 (human platelet antigen [HPA]-1a/b) gene polymorphism.

Methods:

Along an 18-month period, Mexican mestizo thrombophilic patients were prospectively accrued. The SPS phenotype was assessed by aggregometry, whereas a tetra-primer amplification refractory mutation system (ARMS) polymerase chain reaction analysis was used to detect the PLA1 and PLA2 alleles.

Results:

A total of 95 individuals with SPS and 127 healthy donors were studied; in 11 of the donors and 16 of the patients with SPS the A2 allele of the GP IIb/IIIA was found, yielding a weak and nonsignificant association (odds ratio 2.14, 95% CI 0.94-4.85).

Conclusion:

In Mexican mestizo patients, the platelet GP IIIa PLA1/A2 gene polymorphism does not lead to the SPS phenotype.

Epidemiology of Prothrombin G20210A Mutation in the Mediterranean Region

There are many genetic and acquired risk factors that are known to cause venous thromboembolic disorders (VTE). One of these is the Prothrombin G20210A mutation, which has been identified in 1996. Prothrombin G20210A mutation causes higher levels of the clotting factor prothrombin in the blood of carriers, which creates a higher tendency towards blood clotting (hypercoagulability), and therefore the carriers become at higher risk of developing VTE. High prevalence of Prothrombin G20210A mutation was reported in Caucasian populations, but the prevalence was almost absent in non-Caucasians. That was most obvious in countries of South Europe and the Mediterranean region. This review article discusses Prothrombin G20210A mutation, how it causes VTE, the origin of the mutation, and its distribution worldwide with special concentration on the Mediterranean area.

Methotrexate-induced mucositis in acute leukemia patients is not associated with the MTHFR 677T allele in Mexico

Methylenetetrahydrofolate reductase (MTHFR) has two common variants with reduced activity due to polymorphisms at nucleotides 677 and 1298. Both affect folate metabolism and thus remethylation of homocysteine, but are also thought to affect nucleotide synthesis and DNA methylation. Methotrexate (MTX), which interrupts folate metabolism, is used in the treatment of a variety of diseases including acute lymphoblastic leukemia (ALL), but exerts in some patients toxic effects on fast dividing tissues such as mucosal epithelia. The enhanced toxicity may be due to cooperative effects between MTX and MTHFR variants. Accordingly, it has been reported that carrying the 677T allele of the MTHFR is a risk factor for MTX-associated mucositis. As in the Mexican population, which is characterized by a high prevalence of the 677T MTHFR variant, several of its commonly associated defects have not been observed, we investigated the relationship between MTX toxicity and the 677T allele. Out of 28 patients with ALL (CC: 2, CT: 10, TT: 16), 16 had episodes of MTX-associated mucositis (CC: 0, CT: 6, TT: 10). Neither at the gene level nor at the genotype level was a significant association with mucositis found. It may be postulated that the risk of higher MTX toxicity in patients with decreased MTHFR activity could be neutralized by the normally folate rich diet in Mexico.

Hereditary thrombophilia in ethnic Omani patients

Hereditary thrombophilias are a group of inherited conditions that predispose to thrombosis. Mutations like factor V Leiden, prothrombin gene variant 20210A, and hereditary hyperhomocysteinemia are associated with an increased risk for thromboembolism as compared to mutations in natural inhibitors of coagulation. There is also evidence that multiple defects co-exists in persons with a tendency for thrombosis. We studied prothrombotic determinants, namely protein C, protein S, and AT along with factor V Leiden (1691G-->A), prothrombin gene mutation (20210G-->A), CBS 844ins68 mutation, and MTHFR mutation (677C-->T) in consecutive ethnic Omani patients with first episode of a thrombophilic event, namely, deep vein thrombosis (DVT), and/or pulmonary embolism (PE) or thrombosis at an unusual site. Fasting plasma homocysteine was also analyzed. Factor V Leiden and the prothrombin gene mutation were not seen in any patient nor in any control subject studied. The thermolabile MTHFR mutation (677C-->T) was present in 14 patients (35.89%) whereas the CBS 844ins68 mutation was documented in 6 patients (15.38%); 3 patients were common in both groups. Six patients had low protein C (15.38%), two patients had low protein S (5.12%), but none had low AT levels. Interestingly, one patient had triple abnormality, namely, PC deficiency with both CBS 844ins68 mutation as well as the MTHFR mutation (677C-->T) whereas another two patients had the latter two mutations together. This data set, although small, reflects the importance of multiple screening strategies. The yield appears high, emphasizing the referral pattern to a tertiary health center. Of these patients, 43.58% had either or both the hyperhomocysteinemic mutations studied, whereas in 38.46% of these patients, no underlying cause for thrombophilia could be documented.