Sticky Platelet Syndrome

Abstract

Sticky platelet syndrome (SPS) is a thrombophilic thrombocytopathy with familial occurrence and autosomal dominant trait, characterized by an increased in vitro platelet aggregation in response to low concentrations of adenosine diphosphate (ADP) and/or epinephrine (EPI). According to aggregation pattern, three types of the syndrome can be identified (hyperresponse after both reagents, Type I; EPI alone, Type II; ADP alone, Type III). Clinically, the syndrome is associated with both venous and arterial thrombosis. In pregnant women, complications such as fetal growth retardation and fetal loss have been reported. The first thrombotic event usually occurs before 40 years of age and without prominent acquired risk factors. Antiplatelet drugs generally represent adequate treatment. The use of other antithrombotics is usually ineffective and may result in the recurrence of thrombosis. In most patients, low doses of antiplatelet drugs (acetylsalicylic acid, 80-100 mg/d) lead to normalization of hyperaggregability. Combination of SPS with other thrombophilic disorders has been described. Despite several studies investigating platelet glycoproteins' role in platelets' activation and aggregation, the precise defect responsible for the syndrome remains unknown. The aim of this review is to summarize authors' own experience about SPS and the clinical data indexed in selected databases of medical literature (PubMed and Scopus).

Platelet function as a risk factor for venous thromboembolism in the Framingham Heart Study

“…In conclusion, platelet reactivity as measured by lower doses of ADP, epinephrine or standard collagen dose are not strong biomarkers of incident VTE, a finding that is somewhat inconsistent with some small clinical studies [8,17], while being partly consistent in null findings with another study [9]. Future studies may do well to focus on alternate venous biomarkers, or other approaches to platelet testing such as flow-cytometry based assays, whole blood assays or indices like MPV.…”

“…Additionally, there have been a number of studies of platelet aggregation abnormalities referred to as sticky platelet syndrome (SPS), generally performed on patients with unexplained thrombotic events, both venous and arterial, sometimes in families and generally presenting at younger ages [17]. Features of sticky platelet syndrome include definitions based on threshold hyperaggregability to ADP and/or epinephrine, usually at lower dose ranges in LTA.…”

“…While SPS studies often had small or no control samples, they have generally concluded that there may be enrichment of low dose aggregability to ADP and/or epinephrine particularly among individuals with unexplained thrombosis. They have also concluded that aggregation to collagen, ristocetin and thrombin appears normal in these samples [17]. Notably, Weber et al studied patients with unexplained VTE (n=34) for 3 doses each of ADP, epinephrine, collagen and TRAP-6 (a thrombin receptor activating peptide) versus healthy individuals (n=53).…”

“…Inclusion criteria adopted in many of these studies focusing on unexplained thrombosis or cases without family history of thromboembolic events, or bleeding or coagulation disorders, differs significantly from our population-based study. Hayes et al [8] and many of the SPS [17] studies conducted dichotomized threshold tests for ADP and epinephrine whereas most of our analyses focused on continuous trait data. Some studies have combined arterial and venous events in their analysis, making it possible that their findings were driven in part by associations with arterial events.…”

Decreased Threshold of Aggregation to Low-Dose Epinephrine is Evidence of Platelet Hyperaggregability in Patients with Thrombosis

“…Prior studies have described sticky platelet syndrome as a congenital platelet abnormality characterized by clinical and laboratory features, such as hyperaggregability in response to varying concentrations of adenosine diphosphate (ADP) and/or epinephrine (Epi). 1-5 Three aggregation patterns have been associated with SPS: Type I, hyperaggregability to Epi and ADP; Type II, hyperaggregability to Epi alone; 1 , 3 , 5-7 and Type III, hyperaggregability to ADP alone. 2 , 5 These diagnostic criteria are commonly accepted and are used in the majority of published studies available.…”