Platelet Count and Major Bleeding in Patients Receiving Vitamin K Antagonists for Acute Venous Thromboembolism, Findings From Real World Clinical Practice

Association between platelet count and the risk of bleeding among patients with nonvalvular atrial fibrillation taking dabigatran after radiofrequency ablation: a cohort study

Background

A reduction in platelet count or function can be a risk factor for bleeding in anticoagulated patients. However, the association between platelet count and the risk of bleeding among nonvalvular atrial fibrillation (NVAF) patients taking dabigatran remains unclear. The aim of this study was to investigate the relationship between platelet count and the risk of bleeding among patients with NVAF taking dabigatran after radiofrequency ablation.

Methods

In this multicenter, prospective and observational study, a total of 576 NVAF patients treated with dabigatran (110 mg bid) after radiofrequency ablation were recruited from 12 centers in China from February 2015 to December 2017. All patients were followed for 3 months. The association between platelet count and the risk of bleeding was evaluated by Cox proportional hazards regression analysis. To explore the nonlinearity between platelet count and bleeding, we used a Cox proportional hazards regression model with cubic spline functions and smooth curve fitting and a two-piecewise Cox proportional hazards model.

Results

During a median follow-up duration of 87 days, 50 patients experienced bleeding events. Overall, there was an inverse relationship between the risk of bleeding and platelet count. Low platelet count (<100×10⁹/L) were associated with an increased risk of bleeding [hazard ratio (HR), 4.05; 95% confidence interval (CI): 1.32-12.46] compared to normal counts. The adjusted smooth curve showed a nonlinear relationship between platelet count and bleeding events. The inflection point of the platelet count was 105×10⁹/L. For platelet counts <105×10⁹/L, the HR (95% CI) was 0.89 (0.84-0.95), and for platelet counts ≥105×10⁹/L, the HR (95% CI) was 1.01 (0.95-1.08).

Conclusions

Low platelet counts were associated with an increased risk for bleeding among patients with NVAF taking dabigatran after catheter ablation.

Platelet count and risk of major bleeding in venous thromboembolism

The relationship between platelet count and risk of major bleeding in patients with venous thromboembolism (VTE) during anticoagulation remains unclear. We therefore investigated the association between platelet count, measured at VTE diagnosis and before the thrombotic event, and risk of major bleeding. Participants comprised 744 patients with incident VTE derived from the Tromsø Study. Major bleedings were recorded during the first year after VTE. Cox-regression was used to calculate hazard ratios (HRs) for major bleeding across platelet count quartiles.There were 55 major bleedings (incidence rate 9.1/100 person-years, 95% confidence interval [CI] 7.0-11.8). The major bleeding risk increased across quartiles of platelet count measured at VTE diagnosis (P for trend<0.02). In the age- and sex-adjusted model, subjects with platelet count in the highest quartile (≥300x10⁹/L) had a 4.3-fold (95% CI 1.7-10.9) higher risk of major bleeding compared to those with platelet count in the lowest quartile (≤192x10⁹/L), and exclusion of patients with cancer yielded similar results. When platelet count was measured on average 7 years before a VTE, the corresponding HR was 2.5 (95% CI 0.9-6.7). Our results suggest that increasing platelet count, assessed several years before and at VTE diagnosis, is associated with a higher risk of major bleeding, and could be a stable individual marker of major bleeding risk in VTE-patients.

Platelet Count and Bleeding in Patients Receiving Anticoagulant Therapy for Venous Thromboembolism: Lesson from the RIETE Registry

Major bleeding is one of the most dangerous complications for patients undergoing anticoagulant treatment for VTE. Several clinical scores have been planned to identify patients at higher risk of bleeding, and most of them take into consideration the number of platelets in particular if lower than normal. Here we report the clinical experience made with the RIETE registry concerning anticoagulant treatment in the presence of different values of platelets and their related risk of bleeding.

Outcomes after venous thromboembolism in patients with gastric cancer: Analysis of the RIETE Registry

Gastric cancer is the fifth most common malignancy worldwide. Venous thromboembolism is an independent predictor of death among patients with gastric cancer. We aimed to describe the factors associated with mortality, thrombosis recurrence, and bleeding complications in patients with gastric cancer who develop venous thromboembolism. We included 612 patients with gastric cancer and venous thromboembolism in the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) registry from 2001 to 2018. We used Cox proportional hazard ratios and a Fine-Gray model to define factors associated with outcomes. The overall mortality at 6 months was 44.4%. Factors associated with increased 6-month mortality included immobility (HR 1.8, 95% CI 1.3-2.4; p < 0.001), anemia (HR 1.4, 95% CI 1.1-1.8; p < 0.02), and leukocytosis (HR 1.8, 95% CI 1.4-2.3; p < 0.001). Recurrent thrombosis occurred in 6.5% of patients and major bleeding complications in 8.5% of the cohort. Male sex was the main factor associated with thrombosis recurrence (HR 2.1, 95% CI 1.1-4.0; p < 0.02) and hemoglobin below 10 g/dL (HR 1.6, 95% CI 1.05-2.50; p = 0.03) the main factor associated with bleeding. In conclusion, patients with gastric cancer who develop venous thrombosis have a very high likelihood of death. Low hemoglobin in this population is associated with poor outcomes.

Influence of Baseline Platelet Count on Outcomes in Patients With Venous Thromboembolism (from the COMMAND VTE Registry)

The influence of thrombocytopenia on the long-term clinical outcomes has not been thoroughly evaluated in patients with venous thromboembolism (VTE). This study sought to elucidate association of baseline thrombocytopenia with bleeding, recurrent VTE, and mortality risk. We evaluated the influence of baseline thrombocytopenia among 3,012 patients whose baseline platelet counts were available in the COMMAND VTE Registry in Japan with a median follow-up period of 1,219 days. Baseline thrombocytopenia was classified as follows: mild: 100,000 to 150,000/μl; moderate: 50,000 to 99,999/μl; and severe: <50,000/μl. The primary outcome measurement was International Society of Thrombosis and Hemostasis major bleeding, and the secondary outcome measurements were recurrent VTE and all-cause death. There were 167 patients (5.5%) with moderate or severe thrombocytopenia (moderate: 144 patients and severe: 23 patients), 523 patients (17.4%) with mild thrombocytopenia, and 2,322 patients (77.1%) without thrombocytopenia. The cumulative 5-year incidence of major bleeding was markedly higher in patients with moderate or severe thrombocytopenia (moderate or severe 29.4% vs mild: 14.1% vs no thrombocytopenia: 10.6%, p <0.001). After adjusting the confounders, the risk of or thrombocytopenia relative to no thrombocytopenia for major bleeding remained significant (adjusted hazard ratio [HR] 2.15, 95% confidence interval [CI] 1.43 to 3.13, p <0.001). The excess risk of moderate or severe thrombocytopenia relative to no thrombocytopenia was also significant for mortality (adjusted HR 1.54, 95% CI 1.18 to 1.97, p = 0.002), but the risk was neutral for recurrent VTE (adjusted HR 1.05, 95% CI 0.55 to 1.81, p = 0.87). In conclusion, VTE patients with baseline moderate or severe thrombocytopenia had higher risk for major bleeding events and mortality without significant excess risk for recurrent VTE events.

Molecular and Clinical Issues about the Risk of Venous Thromboembolism in Older Patients: A Focus on Parkinson's Disease and Parkinsonism

Venous thromboembolism (VTE) is a common and potentially life-threatening condition which includes both deep-vein thrombosis (DVT) and pulmonary embolism (PE). VTE has a significant clinical and epidemiological impact in the elderly, and its incidence increases to more than 1% per year in older patients, suggesting the presence of specific age-related risk factors in this population. Immobilization seems to predominate as the main cause in patients admitted for medical acute illness in medicine wards, and there is evidence of a high risk in older patients with immobilization resulting from advanced forms of Parkinson’s disease (PD), regardless of the presence of an acute medical condition. In this review, we would to discuss the recent evidence on clinical, molecular and epidemiological features of VTE in older frail subjects focusing on patients with PD and parkinsonism. We also discuss some therapeutic issues about the risk prevention and we suggest a thorough comprehensive geriatric assessment that can represent an optimal strategy to identify and prevent the VTE risk in these patients.

Appropriateness of antiplatelet therapy for primary and secondary cardio- and cerebrovascular prevention in acutely hospitalized older people

AIMS

Antiplatelet therapy is recommended for the secondary prevention of cardio- and cerebrovascular disease, but for primary prevention it is advised only in patients at very high risk. With this background, this study aims to assess the appropriateness of antiplatelet therapy in acutely hospitalized older people according to their risk profile.

METHODS

Data were obtained from the REPOSI register held in Italian and Spanish internal medicine and geriatric wards in 2012 and 2014. Hospitalized patients aged ≥65 assessable at discharge were selected. Appropriateness of the antiplatelet therapy was evaluated according to their primary or secondary cardiovascular prevention profiles.

RESULTS

Of 2535 enrolled patients, 2199 were assessable at discharge. Overall 959 (43.6%, 95% CI 41.5-45.7) were prescribed an antiplatelet drug, aspirin being the most frequently chosen. Among patients prescribed for primary prevention, just over half were inappropriately prescribed (52.1%), being mainly overprescribed (155/209 patients, 74.2%). On the other hand, there was also a high rate of inappropriate underprescription in the context of secondary prevention (222/726 patients, 30.6%, 95% CI 27.3-34.0%).

CONCLUSIONS

This study carried out in acutely hospitalized older people shows a high degree of inappropriate prescription among patients prescribed with antiplatelets for primary prevention, mainly due to overprescription. Further, a large proportion of patients who had had overt cardio- or cerebrovascular disease were underprescribed, in spite of the established benefits of antiplatelet drugs in the context of secondary prevention.