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To Bleed or Not To Bleed… FREE TO VIEW

Tahuanty A. Pena, MD; for the China Venous Thromboembolism (VTE) Study Group
Author and Funding Information

From the Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University/Detroit Medical Center.

Correspondence to: Tahuanty A. Pena, MD, Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University/Detroit Medical Center, 3990 John R., 3 Hudson, Detroit, MI 48201; e-mail: tpena@med.wayne.edu


Financial/nonfinancial disclosures: The author has reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).


© 2010 American College of Chest Physicians


Chest. 2010;138(6):1520. doi:10.1378/chest.10-1291
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To the Editor:

Wang et al (February 2010)1 reported that thrombolytic therapy for pulmonary thromboembolism with one-half the dose of recombinant tissue-type plasminogen activator (rt-PA) was associated with similar clinical improvement as the full dose, but complications of bleeding were greatly reduced. This is a landmark study that addresses one of the main issues that limit the use of this therapy: concerns about bleeding complications. Ibrahim et al2 had already shown, in a 15,000-patient cohort, that in patients with pulmonary thromboembolism receiving thrombolytics bleeding complications occur in approximately 5.3% of patients.

Decreasing the frequency of that feared complication is a major step in the use of this therapeutic approach. To illustrate this better, we organized the data obtained from Wang et al in a 2 × 2 format (Table 1), from which we can calculate the attributable risk percentage (AR%), which is the percentage of bleeding complications that could be prevented among patients receiving a regular dose of rt-PA if they received a low dose rt-PA, with the following formula:

AR% = ([Incidence of bleedingFull dose of rt-PA − Incidence of bleedingLow dose of rt-PA]/Incidence of bleedingFull dose of rt-PA) × 100 = ([32/100 − 17/100]/[32/100]) × 100 = 46.8 = 47%.

Table Graphic Jump Location
Table 1 —Major Bleeding Complications in Patients From the Study by Wang et al1

rt-PA = recombinant tissue-type plasminogen activator.

Furthermore, if we want to have a better idea of what this potential change in practice may do to the group of patients to which it is targeted, then we should look at the population attributable risk percentage (PAR%), calculated with the following formula:

PAR% = ([Incidence of bleedingTotal population – Incidence of bleedingLow dose rt-PA]/Incidence of bleedingTotal population) ×100 = ([23.7/100 – 17/100]/23.7/100) ×100 = 28.2%.

This represents the percentage of bleeding complications in the patient population with pulmonary thromboembolism who are given thrombolytics that is due to receiving the regular dose of rt-PA and could be eliminated by using a lower dose of rt-PA.

Certainly, the treatment of pulmonary thromboembolism with the use of thrombolytics in hemodynamically unstable patients has the potential to save lives.3 We look forward to using thrombolytics in a safer manner, and even though more studies are needed to further validate the data presented in the study by Wang et al,1 there is a lot of promise if we can achieve a clinically relevant therapeutic effect with a major decrease in side effects.

Wang C, Zhai Z, Yang Y, et al; for the China Venous Thromboembolism (VTE) Study Group for the China Venous Thromboembolism (VTE) Study Group Efficacy and safety of low dose recombinant tissue-type plasminogen activator for the treatment of acute pulmonary thromboembolism: a randomized, multicenter, controlled trial. Chest. 2010;1372:254-262. [CrossRef] [PubMed]
 
Ibrahim SA, Stone RA, Obrosky DS, Geng M, Fine MJ, Aujesky D. Thrombolytic therapy and mortality in patients with acute pulmonary embolism. Arch Intern Med. 2008;16820:2183-2192. [CrossRef] [PubMed]
 
Hirsh J, Guyatt G, Albers GW, Harrington R, Schünemann HJ. American College of Chest Physician American College of Chest Physician Antithrombotic and thrombolytic therapy: American College of Chest Physicians evidence-based clinical practice guidelines (8th edition). Chest. 2008;1336 Suppl:110S-112S. [CrossRef] [PubMed]
 

Figures

Tables

Table Graphic Jump Location
Table 1 —Major Bleeding Complications in Patients From the Study by Wang et al1

rt-PA = recombinant tissue-type plasminogen activator.

References

Wang C, Zhai Z, Yang Y, et al; for the China Venous Thromboembolism (VTE) Study Group for the China Venous Thromboembolism (VTE) Study Group Efficacy and safety of low dose recombinant tissue-type plasminogen activator for the treatment of acute pulmonary thromboembolism: a randomized, multicenter, controlled trial. Chest. 2010;1372:254-262. [CrossRef] [PubMed]
 
Ibrahim SA, Stone RA, Obrosky DS, Geng M, Fine MJ, Aujesky D. Thrombolytic therapy and mortality in patients with acute pulmonary embolism. Arch Intern Med. 2008;16820:2183-2192. [CrossRef] [PubMed]
 
Hirsh J, Guyatt G, Albers GW, Harrington R, Schünemann HJ. American College of Chest Physician American College of Chest Physician Antithrombotic and thrombolytic therapy: American College of Chest Physicians evidence-based clinical practice guidelines (8th edition). Chest. 2008;1336 Suppl:110S-112S. [CrossRef] [PubMed]
 
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