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 The authors added in their unpublished data.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.

Sticky Platelet Syndrome: A Case Report and Review of the Literature

Thrombosis has been attributed to platelet function abnormalities in a variety of vascular diseases. A patient with superior sagittal sinus thrombosis noted to have a normal work- up for hypercoagulable state but who had hyperaggregability of platelets after stimulation with epinephrine is described. A di agnosis of sticky platelet syndrome, type II was eventually made.

Sticky Platelet Syndrome: A Common Cause of Unexplained Arterial and Venous Thrombosis

Sticky platelet syndrome (SPS) was first described in 1983. However, not until 1995 did the prevalence of SPS receive significant recognition in the medical literature. In 1995 we began to routinely add an SPS evaluation to patients re ferred for assessment for causation of arterial and venous thromboses to a large thrombosis hemostasis referral center. The results of our first 2-year experience suggest SPS to be a common cause of arterial and venous thromboses. With respect to otherwise unexplained venous thrombosis, the prevalence of SPS approximates that of activated protein C resistance (APC- R). During the past 24 months, we have evaluated 153 patients referred for evaluation of unexplained arterial or venous events. An evaluation for common and uncommon blood coagulation protein defects and SPS has been applied to these patients. It has been found that SPS accounted for about 21 % of otherwise unexplained arterial events (acute myocardial infarction, cere brovascular thrombosis, transient cerebral ischemic attacks, retinal thrombosis, and peripheral arterial thrombosis) and ac counted for about 13.2% of otherwise unexplained venous events (deep vein thrombosis, with or without pulmonary em bolus). These findings strongly suggest SPS to be a common cause of arterial and venous thromboses and a workup for SPS should be considered a routine assay in the workup of indi viduals with otherwise unexplained arterial or venous throm botic events. Because treatment with heparin or warfarin will not alleviate the thrombotic tendency of SPS, but simple aspirin therapy almost always will correct the defect and protect the individual from second events, it is particularly important to define the presence of this defect. Key Words: Thrombosis— Platelet defects—DVT—Coronary thrombosis—Cerebral thrombosis—Recurrent miscarriage.

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.

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.

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.

Nine kindreds of familial sticky platelet syndrome phenotype

INTRODUCTION

Sticky platelet syndrome (SPS) is most likely a hereditary thrombophilia characterized by platelet hyperaggregation after low concentrations of platelet inducers--adenosine diphosphate and/or epinephrine. We present 9 kindreds with SPS familial occurrence.

MATERIAL AND METHODS

Familial trait of SPS was looked up in the database of the National Center of Hemostasis and Thrombosis. Families with at least 3 SPS-positive members were studied, described, and presented.

RESULTS

In the group of 1093 symptomatic patients, SPS was confirmed in 240 cases. Familial occurrence with at least 3 SPS-positive relatives was found in 9 cases.

CONCLUSION

The exact pathogenesis of SPS is not sufficiently explained. Our findings seem to support the idea that SPS might have an autosomal dominant hereditary fashion.

Sticky platelet syndrome and thrombocythemia

Platelets are intimately involved in the pathogenesis of thromboembolic disorders, especially arterial forms of thrombosis. Although most arterial thromboses develop on the basis of endothelial injuries, some do not. In these instances "hyperactive" platelets could be the cause. Hyperaggregable platelets have been described in association with a number of acquired disease entities whereby the cause-and-effect relationship is unclear. In contrast, the sticky platelet syndrome is a congenital, autosomal dominant disorder, characterized by hyperaggregable platelets in response to ADP, epinephrine, or both. Patients usually seek treatment for transient or permanent arterial vascular occlusions. These are often precipitated by stressful events. Treatment with low-dose aspirin (81 mg/day) reverses clinical symptoms and hyperaggregability in the laboratory.

Primary thrombophilia in Mexico III: A prospective study of the sticky platelet syndrome

During an 18-month period, 10 consecutive Mexican mestizos with a dinical marker associated with a primary hypercoagulable state were studied. The assessment of the sticky platelet syndrome (SPS) was done by the method described by Mammen. In addition, the activated protein C resistance phenotype, coagulation protein C activity and antigen, coagulation protein S, antithrombin III, plasminogen, tissue-type plasminogen activator activity, plasminogen activator inhibitor activity, plasminogen activator inhibitor type 1, IgG and IgM isotypes of anti-phospholipid antibodies, homocysteine levels, the factor V gene Leiden mutation, the 677 C->T mutation in the 5,10-methylen-tetrahydrofolate-reductase (MTHFR), and the G20210A polymorphism in the 3'-untranslated region of the prothrombin gene were studied. Six patients with the SPS were identified: only one displayed this as the single thrombophilic abnormality; in five others, additional thrombosis-prone conditions were found: heterozygosity for the MTHFR 677 gene mutation in five cases; and, in one case each, heterozygosity for the factor V Leiden mutation, heterozygosity for the factor II G20210A mutation, and antiphospholipid antibodies in another. Four of the six patients had a family history of thrombophilia. All patients were treated with aspirin and no new vasoocclusive episodes have been recorded. SPS in not an infrequent finding in Mexican mestizo thrombophilic patients and may contribute to thrombophilia.