Platelet Count and the Risk of Bleeding in Hospitalized Patients with Venous Thromboembolism Starting Anticoagulant Therapy

Abstract

In a series of patients with pulmonary embolism (PE) we have previously demonstrated that the risk of recurrent PE was inversely correlated to platelet count (PIC) levels. To find out whether PIC levels were also associated to a different incidence of heparin-related bleeding complications, we report our experience with 1,103 consecutive patients with venous thromboembolism (VTE) receiving full-dose heparin therapy. Six points of clinical and laboratory information were recorded on admission and then compared to the development of bleeding: the patient’s age and sex; the etiology of VTE; the type of heparin used (unfractioned, UFH, vs. low-molecular-weight, LMWH), the presence or lack of PE findings on lung scan, and the PIC levels on admission. Bleeding occurred in 64/1,103 patients (6%). Patients who bled were significantly older than those who did not (72 ± 11 vs. 64 ± 17 years; p = 0.0005). There were no significant differences in bleeding rate according to any of the risk factors that could have predisposed to VTE, but patients treated with UFH bled significantly more frequently than those on LMWH (48/636 vs. 16/467; odds ratio: 2.30; 95% confidence interval: 1.25-4.28). Finally, mean PIC levels were significantly lower at VTE diagnosis in patients who subsequently bled (227 ± 112 vs. 262 ± 110 × 10⁹ liters^-1; p = 0.01). The logistic regression analysis confirmed that all three variables were independent risk factors for bleeding complications. This is the first study to demonstrate that PIC levels (within the normal range) are inversely correlated with the risk of heparin-related bleeding. These findings may be of interest not only from the point of view of pathogenesis but also clinically, as they may be used in the decision as to which VTE patients could receive heparin therapy at home.

Platelet count and outcome in patients with acute venous thromboembolism

“…Accurate prediction of the risk for bleeding in patients with acute VTE is a challenging task, especially to avoid over-anticoagulation in those at high-risk. However, existing bleeding risk scores do not have sufficiently accuracy and power to discriminate between VTE patients who are at high risk for short-term major bleeding and those who are not (1,2,(18)(19)(20)(21)(22)(23). Our finding of a U-shaped relationship between platelet count and outcome may be valuable in clinical practice.…”

A prospective, randomized, sequential crossover trial oflarge‐volume versus normal‐volume leukapheresis procedures:effects on serum electrolytes, platelet counts, and other coagulation measures

“…Risk factors for bleeding complications during heparin therapy are deduced from studies in patients with acute coronary syndrome or with deep venous thrombosis. In these studies, factors such as the patient's age, 30 the concomitant use of aspirin, recent surgery or trauma, 31 low platelet counts, 30 a body surface area <2 m², high doses of heparin, and a history of malignancy 32 were associated with an elevated risk of bleeding.…”

Secondary Prevention of Venous Thromboembolism: A Role for Low-Molecular-Weight Heparin

“…The initial treatment of VTE patients consisted of subcutaneous dalteparin (Fragmin ® , Pharmacia, Sweden), according to a previously reported schedule [5]. Just before being discharged, patients were allocated to receive either dalteparin or coumarin.…”