How much do we know about the platelet transfusion threshold?

The influence of bleeding on trigger changes for platelet transfusion in patients with chemotherapy-induced thrombocytopenia

BACKGROUND

For patients with thrombocytopenia without bleeding risk factors, a platelet transfusion trigger of 10 × 10(9) /L is recommended. No studies have evaluated the clinicians' decision-making process leading to trigger changes.

STUDY DESIGN AND METHODS

We report on the evaluation of trigger changes and the relation with bleeding. Eighty patients previously enrolled in the SPRINT trial represent the patient population for the current analysis.

RESULTS

Seventy-four patients had a starting trigger of 10 × 10(9) /L. Only a minority of patients treated with chemotherapy alone (3/12, 25%) and autologous transplant (6/15, 40%) had a change in their trigger in contrast to the majority of allogeneic transplant (37/47, 79%; p = 0.001 and p = 0.009, respectively, when compared to allogeneic transplant group). Bleeding was the main reason reported by clinicians for a trigger change, but the occurrence of significant bleeding (Grade 2-4) was similar in patients with or without a trigger change (51 and 54%, p = 1.00). Clinicians were influenced by the bleeding system: grade 1 mucocutaneous bleeding leading to a trigger change was overrepresented (71% of cases), as was grade 2 genitourinary bleeding not leading to a trigger change (57% of cases).

CONCLUSION

A universal trigger of 10 × 10(9) /L may not be maintained in a diverse population of patients with their respective bleeding risk factors. Because the trigger is changed often, it may not be as effective as previously believed.

Do all patients with hematologic malignancies and severe thrombocytopenia need prophylactic platelet transfusions? Background, rationale, and design of a clinical trial (trial of platelet prophylaxis) to assess the effectiveness of prophylactic platelet transfusions

Although considerable advances have been made in many aspects of platelet transfusion therapy in the last 30 years, some areas continue to provoke debate, including the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding in patients with bone marrow failure. We have designed a randomized controlled trial to compare prophylactic platelet use with a threshold of a platelet count of 10 x 10(9)/L with no prophylaxis in adult thrombocytopenic patients with hematologic malignancies. The trial question is whether a no-prophylactic policy for the use of platelet transfusions in patients with hematologic malignancies is not inferior to a threshold prophylactic policy at 10 x 10(9)/L, for bleeding at World Health Organization (WHO) grade 2, 3, or 4, up to 30 days from randomization. The primary outcome measure is the proportion of patients who have a significant clinical bleed, defined as WHO grade 2 or higher up to 30 days from randomization. Subsidiary clinical outcome measures include time to first bleed and a descriptive analysis of all severe bleeds. A bleeding assessment form is completed daily for all study subjects until day 30 from randomization. Minor modifications were made to the definitions at WHO grades 1 and 2 for petechiae and duration of nose bleeds, after piloting of the bleeding assessment forms. This study has been designed as a 2-stage randomized trial with an interim analysis planned after a minimum of 100 patients had been randomized and had completed their period of observation. Patients have initially been enrolled through 3 United Kingdom hematology centers. The interim analysis has been completed, and the results have confirmed a final sample size of 600 patients. Recruitment is now being extended to other centers in United Kingdom and Australia. Local research nurses are not blinded to treatment allocation, but a number of measures to reduce risk of assessment bias include repeated education around standard operating procedures, common definitions, and duplication of assessments. The expected completion date for the 5-year study is December 2011.

Profound thrombocytopenia and survival of hematopoietic stem cell transplant patients without clinically significant bleeding, using prophylactic platelet transfusion triggers of 10 x 10(9) or 20 x 10(9) per L

BACKGROUND

A trigger of 10 x 10(9) per L for prophylactic platelet (PLT) transfusions is generally recommended for stable thrombocytopenic patients who receive chemotherapy, based on studies showing similar incidence, severity, and fatality of bleeding compared with the 20 x 10(9) per L trigger. The outcome of thrombocytopenic nonbleeding patients has not been well described. This retrospective analysis evaluates thrombocytopenia and survival of 381 hematopoietic stem cell transplant (HSCT) patients without clinically significant bleeding, with 10 x 10(9) and 20 x 10(9) per L prophylactic triggers.

STUDY DESIGN AND METHODS

A total of 170 patients who received prophylactic PLT transfusions at 20 x 10(9) per L (1997-1998, SP1) and 211 patients who had prophylaxis at 10 x 10(9) per L (1999-2001, SP2) were identified as nonbleeding patients. PLT counts and clinical complications were assessed within 100 days from HSCT.

RESULTS

PLT counts less than or equal to 10 x 10(9) per L were found in 69.2 percent of patients in SP2 and 38.3 percent in SP1 (p < 0.001). Profound thrombocytopenia (4+ PLT counts <or=10 x 10(9)/L) was found in 19.0 percent of patients in SP2 and 7.0 percent in SP1 (p = 0.001). Patients with profound thrombocytopenia had significantly increased early mortality (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.25-8.07) and significantly reduced overall survival (hazard ratio [HR], 1.95; 95% CI, 1.28-2.97) compared to patients with 0 to 3 PLT counts less than or equal to 10 x 10(9) per L. The association of profound thrombocytopenia with early mortality was more notable in SP2.

CONCLUSION

The 10 x 10(9) per L transfusion trigger is associated with significantly greater exposure to low PLT counts. Nonbleeding patients with profound thrombocytopenia were at significantly greater risk of dying compared with nonthrombocytopenic patients. These results suggest that safety of the 10 x 10(9) per L trigger should be more thoroughly evaluated.

Acute bleeding complications in patients after hematopoietic stem cell transplantation with prophylactic platelet transfusion triggers of 10�נ109and 20�נ109per L

BACKGROUND

Prophylactic platelet (PLT) transfusions are given as a standard care in patients with hematologic malignancies undergoing hematopoietic stem cell transplantation (HSCT). This retrospective analysis evaluates utilization of blood transfusions, risk of bleeding, and survival in 480 HSCT patients at 10 x 10(9) and 20 x 10(9) per L prophylactic trigger levels.

STUDY DESIGN AND METHODS

A total of 224 patients received prophylactic PLT transfusions at 20 x 10(9) per L threshold (1997-1998, SP1); 256 patients had prophylaxis at 10 x 10(9) per L (1999-2001, SP2). Bleeding scores were assigned daily.

RESULTS

A slight reduction in PLT transfusions per patient in SP2 compared with SP1 was not statistically significant (odds ratio, 0.82; 95% confidence interval, 0.51-1.33; p = 0.416), yet a significantly higher proportion of patients in SP2 had PLT counts less than or equal to 10 x 10(9) per L compared to SP1 (p < 0.001). In patients who bled, however, there was no excess exposure to low PLT counts before bleeding started. A substantial number of patients who bled received PLT transfusions above the goal before bleeding started (82.9% in SP2, 41.5% in SP1) because of medical complications that associated with increased risk of bleeding. Bleeding incidence was similar in both study periods (21.9% in SP1, 16.4% in SP2; p = 0.526). Bleeding was significantly associated with reduced survival in both study periods.

CONCLUSIONS

Patients who bled were usually placed on a higher threshold before the onset of their major bleeding event and were not exposed to additional risk of bleeding from thrombocytopenia. Similarity in bleeding incidence between study periods appears to associate with adjustments to high-risk conditions and may not reflect consequences of the lower transfusion threshold.

Feasibility and usefulness of self-assessment of bleeding in patients with haematological malignancies, and the association between platelet count and bleeding

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the collection of daily prospective information about bleeding outcomes in patients with thrombocytopenia, including information obtained by patient self-assessment.

MATERIALS AND METHODS

Consecutive patients with haematological malignancies were enrolled in a study of bleeding data collection during the period of thrombocytopenia. A short educational session and information sheet was designed for self-assessment. Platelet counts and all transfusions were recorded daily. Bleeding scores were translated into World Health Organization (WHO) bleeding grades.

RESULTS

Nineteen patients were included in the study. Four-hundred and ten days of thrombocytopenia were eligible for assessment of bleeds. Self-assessment was feasible, as defined by the total proportion of days on which self-assessment was completed (70%, 288 thrombocytopenic days). There was 86% agreement between bleeding data collected by self-assessment and by medical examination using a structured assessment form. Examples of discrepancies included the duration of petechiae/bruises and the reporting of minor bleeding. There was no evidence for an association between patients' morning platelet count and daily WHO bleeding grade. The incidences of WHO grade 1 and grade 2 bleeding on days with platelet counts < or = 10 x 10(9)/l, 11-20 x 10(9)/l, and > 20 x 10(9)/l were similar and did not reveal higher rates of bleeding at lower counts.

CONCLUSIONS

Patient self-assessment can help to support comprehensive daily prospective monitoring of bleeding, specifically facilitating data collection following hospital discharge. The discrepancies between self-assessment and medical examination highlight the need to develop a validated international assessment tool. The association among platelet count, risk of bleeding and role of prophylactic platelet transfusions needs further evaluation in larger prospective trials.

Platelet transfusion prophylaxis for patients with haematological malignancies: where to now?

National guidelines for platelet transfusion in many countries recommend that the general platelet transfusion trigger for prophylaxis is 10x10(9)/l. This annotation reviews the evidence for this threshold level and discusses other current unresolved issues relevant to platelet transfusion practice such as the optimal dose and the clinical benefit of a strategy for the prophylactic use of platelet transfusions when the platelet count falls below a given threshold.