Risk factors of hospitalisation for thrombosis in adults with primary immune thrombocytopenia, including disease-specific treatments: a French nationwide cohort study

The immune thrombocytopenia paradox: Should we be concerned about thrombosis in ITP?

Despite the predisposition to bleeding, patients with immune thrombocytopenia (ITP) may also have an increased risk of arterial and venous thrombosis, which can contribute to significant morbidity. The risk of thrombosis increases with age and the presence of cardiovascular risk factors. This narrative review explores the multifactorial nature of thrombosis in ITP, focusing on new pathological mechanisms, emerging evidence on the association between established treatments and thrombotic risk, the role of novel treatment approaches, and the challenges in assessing the balance between bleeding and thrombosis in ITP. The review also explores the challenges in managing acute thrombotic events in ITP, since the platelet count does not always reliably predict either the risk of bleeding or thrombosis and antithrombotic strategies lack specific guidelines for ITP. Notably, second-line therapeutic options, such as splenectomy and thrombopoietin receptor agonists (TPO-RAs), exhibit an increased risk of thrombosis especially in older individuals or those with multiple thrombotic risk factors or previous thrombosis, emphasizing the importance of careful risk assessment before treatment selection. In this context, it is important to consider second-line therapies such as rituximab and other immunosuppressive agents, dapsone and fostamatinib, which are not associated with increased thrombotic risk. In particular, fostamatinib, an oral spleen tyrosine kinase inhibitor, has promisingly low thrombotic risk. During the current era of the emergence of several novel ITP therapies that do not pose additional risks for thrombosis, it is critical to outline evidence-based strategies for the prevention and treatment of thrombosis in ITP patients.

The Incidence and Characteristics of Thrombosis in Patients with Immune thrombocytopenia: A Retrospective Cohort Study

Introduction

This study aims to investigate the incidence, clinical characteristics, and prognosis of thrombosis in Chinese patients with immune thrombocytopenia (ITP).

Methods

This was a single-center, retrospective study of adult patients with ITP at the Henan Provincial People's Hospital from January 2018 to June 2023.

Results

A total of 3216 adult patients with primary ITP were included in the study period, with 25 (0.93%) having thrombotic events. The average age of 25 patients with thrombosis is 62.76±12.79 years, including 11 males and 14 females. In addition, among the 25 thrombotic events, 19 cases were arterial thrombosis (AT), and 6 cases were venous thrombosis (VT). The incidence of AT is higher than that of VT (P=0.009). There was no obvious difference in clinical characteristics between the two groups. The median platelet count at the time of thrombosis in 25 patients was 35 (23, 52) ×109/L. At the onset of thrombosis, 23 patients (92.0%) had a low PLT (<100×109/L). One patient with ischemic stroke died in the hospital due to severe infection.

Conclusion

ITP may be considered a bleeding disorder with a high risk of thrombosis, and AT is more common than VT in the Chinese population.

Risk-based and individualised management of bleeding and thrombotic events in adults with primary immune thrombocytopenia (ITP)

Although bleeding is one of the main symptoms of primary immune thrombocytopenia (ITP), risk factors for bleeding have yet to be fully established. Low platelet count (PC; <20-30 × 109 /L) is generally indicative of increased risk of bleeding. However, PC and bleeding events cannot be fully correlated; many other patient- and disease-related factors are thought to contribute to increased bleeding risk. Furthermore, even though ITP patients have thrombocytopenia and are at increased risk of bleeding, ITP also carries higher risk of thrombotic events. Factors like older age and certain ITP treatments are associated with increased thrombotic risk. Women's health in ITP requires particular attention concerning haemorrhagic and thrombotic complications. Management of bleeding/thrombotic risk, and eventually antithrombotic therapies in ITP patients, should be based on individual risk profiles, using a tailored, patient-centric approach. Currently, evidence-based recommendations and validated tools are lacking to support decision-making and help clinicians weigh risk of bleeding against thrombosis. Moreover, evidence is lacking about optimal PC for achieving haemostasis in invasive procedures settings. Further research is needed to fully define risk factors for each event, enabling development of comprehensive risk stratification approaches. This review discusses risk-based and individualised management of bleeding and thrombosis risk in adults with primary ITP.

Is splenectomy a good strategy for refractory immune thrombocytopenia in adults?

Rituximab and thrombopoietin receptor agonists (TPO-RAs) have profoundly changed the management of immune thrombocytopenia (ITP) over the last 20 years. Even if most current guidelines put splenectomy, rituximab and TPO-RAs on the same treatment level, most clinicians and patients clearly prefer to postpone splenectomy and to multiply the lines of medical treatment before considering surgery. The management of ITP refractory to rituximab and TPO-RAs is challenging. Splenectomy is currently performed much less frequently because of a better knowledge of its complications, particularly severe late infections and deep vein thrombosis, and the inability to reliably predict its effectiveness. Furthermore, there is a reluctance to propose splenectomy when other treatments have been ineffective, based on the not well-documented risk that splenectomy could not be effective in such a case. The objective of this update was to review the most recent published data on the long-term tolerability and side effects of splenectomy and the predictors of response and efficacy, especially for patients exposed to multiple medical lines. This update can help physicians and patients with failure of multiple lines of therapy make an informed decision on the indication for splenectomy with the help of up-to-date data.

Risk of thrombotic events in immune thrombocytopenia patients treated with thrombopoietic agents: a systematic review and meta-analysis

BACKGROUND

Immune thrombocytopenia (ITP), which is a well-known hemorrhagic disorder characterized by low platelet counts, has been shown to be associated with the risk of thrombosis. Thrombopoietic agents (TAs) are extensively used as second-line treatments for ITP, effectively reducing the risk of hemorrhage. However, thrombosis, a potential adverse effect of TAs, raises clinical challenges.

METHODS

The MEDLINE(PubMed), Embase, and the Cochrane Library databases were systematically searched for relevant studies, including both single-arm trials and randomized controlled trials (RCTs), without language restrictions.

RESULTS

A total of 17 RCTs comprising 2,105 patients and 29 single-arm trials comprising 3,227 patients were included. In the single-arm meta-analysis, the pooled rate of overall thrombotic events in ITP patients receiving TAs was 2.2% (95% CI 1.0% - 3.7%). In RCTs, a higher incidence of thrombosis (33/1425 vs. 4/680) and higher risk ratios (RR) of overall, arterial, and venous thrombotic events (1.73, 95% CI [0.88, 3.39], P = 0.113; RR 1.98, 95% CI [0.80, 4.92], P = 0.141; RR 1.06, 95% CI [0.46, 2.41], P = 0.895, respectively) were observed in the TAs group than in the control group, although the differences were not significant. Subgroup analysis demonstrated that hetrombopag was the only TA with no increased thrombotic risk (rate 0.3% 95% CI [0.0 - 1.5%]; RR 0.76, 95% CI [0.03, 18.41], P = 0.864) compared to eltrombopag, avatrombopag, romiplostim, and rhTPO. Subgroup analyses also revealed that ITP patients with advanced age (3.7% vs. 1.3%, P = 0.132) or with a thrombotic history (3.0% vs. 1.4%, P = 0.257), and patients who received TAs therapy for a long duration (4.7% vs. 0.1%, P < 0.001) had an increased risk of thrombosis.

CONCLUSION

Our findings suggest ITP patients treated with TAs have a nonsignificantly higher risk of overall, arterial, and venous thrombotic events. Furthermore, hetrombopag is the recommended TA to avoid thrombophilia. Patients receiving long-term TAs, as well as elderly ITP patients or those with a history of thrombosis, face an increased thrombotic risk. In general, clinicians should consider potential thrombotic risks, address underlying risk factors, and ensure ongoing monitoring and follow-up when treating ITP patients with TAs.

Intravascular hemolysis and multitreatment predict thrombosis in patients with autoimmune hemolytic anemia

BACKGROUND

Thrombosis may complicate autoimmune hemolytic anemia (AIHA), but its predictors are still lacking, and no clear-cut indications for anticoagulant prophylaxis are available.

OBJECTIVES

To characterize frequency and severity of thromboses in AIHA patients and identify risk factors for thrombosis that may advise primary anticoagulant prophylaxis.

PATIENTS/METHODS

A total of 287 consecutive AIHA patients diagnosed and followed from 1978 at a tertiary Italian center were retrospectively studied; 174 of them were prospectively evaluated from January 2020 until December 2021. AIHA relapse, thrombosis occurrence, and primary anticoagulant prophylaxis were evaluated.

RESULTS

Thirty-three AIHA patients (11.4%) experienced thrombosis, 70% of whom hospitalized. The cumulative thrombosis incidence was higher in patients with lactate dehydrogenase (LDH) ≥ 1.5 (hazard ratio [HR] 3.22), in those experiencing infections (HR 3.57), receiving transfusions (HR 3.06), rituximab (HR 3.3), or cyclophosphamide (HR 2.67). By multivariable analysis, LDH, transfusions, rituximab, and cyclophosphamide treatment emerged as independent factors associated with thrombosis. Among 174 patients prospectively followed in the past 2 years, we observed 70 acute hemolytic episodes in 45 patients; 33/45 displayed LDH ≥1.5 × upper limit of normal, and 17 received anticoagulant prophylaxis with low molecular weight heparin for a median of 70 days (30-300). In those receiving prophylaxis no thrombotic complications occurred, whereas five thrombotic episodes were registered in the remaining 16 cases.

CONCLUSIONS

Thrombosis was observed in about 11% of AIHA patients, mainly grade 3, and associated with intravascular hemolysis, need of transfusions, multitreatment, and infections, advising primary anticoagulant prophylaxis in these settings.

Immune Thrombocytopenic Purpura as a Hemorrhagic Versus Thrombotic Disease: An Updated Insight into Pathophysiological Mechanisms

Immune thrombocytopenic purpura (ITP) is a blood disorder characterized by a low platelet count of (less than 100 × 109/L). ITP is an organ-specific autoimmune disease in which the platelets and their precursors become targets of a dysfunctional immune system. This interaction leads to a decrease in platelet number and, subsequently, to a bleeding disorder that can become clinically significant with hemorrhages in skin, on the mucous membrane, or even intracranial hemorrhagic events. If ITP was initially considered a hemorrhagic disease, more recent studies suggest that ITP has an increased risk of thrombosis. In this review, we provide current insights into the primary ITP physiopathology and their consequences, with special consideration on hemorrhagic and thrombotic events. The autoimmune response in ITP involves both the innate and adaptive immune systems, comprising both humoral and cell-mediated immune responses. Thrombosis in ITP is related to the pathophysiology of the disease (young hyperactive platelets, platelets microparticles, rebalanced hemostasis, complement activation, endothelial activation, antiphospholipid antibodies, and inhibition of natural anticoagulants), ITP treatment, and other comorbidities that altogether contribute to the occurrence of thrombosis. Physicians need to be vigilant in the early diagnosis of thrombotic events and then institute proper treatment (antiaggregant, anticoagulant) along with ITP-targeted therapy. In this review, we provide current insights into the primary ITP physiopathology and their consequences, with special consideration on hemorrhagic and thrombotic events. The accumulated evidence has identified multiple pathophysiological mechanisms with specific genetic predispositions, particularly associated with environmental conditions.

Simultaneous Occurrence of Cerebral Venous Sinus Thrombosis and Immune Thrombocytopenic Purpura in a Patient with a History of COVID-19 Infection

Since the emergence of the coronavirus disease 2019 (COVID-19) pandemic, multiple but rare complications of this infection have been described, comprising cerebral venous sinus thrombosis (CVST) and immune thrombocytopenic purpura (ITP). Although these two complications have been reported as separate entities, to the best of our knowledge, their concurrent presentation has not been reported. In this case report, we present a middle-aged man with a history of COVID-19 infection who developed a sudden-onset severe occipital headache followed by right-sided blindness (right homonymous hemianopia). Upon his diagnostic workup, brain computed tomography scan with and without contrast was indicative of thrombosis of the left transverse venous sinus and hemorrhagic venous infarction. In addition, laboratory data revealed thrombocytopenia, which upon investigation confirmed a diagnosis of ITP. We postulate three pathophysiological mechanisms for this circumstance: either COVID-19 infection caused ITP and then ITP gave rise to CVST, or COVID-19 complications themselves resulted in ITP and CVST independently and simultaneously, or another plausible mechanism is immune-mediated thrombocytopenia caused by the anti-platelet 4-factor antibody, which is the proposed mechanism for CVST after the COVID-19 vaccine.