Analysis of Partial Thromboplastin Times in Patients With Pulmonary Embolism During the First 48 Hours of Anticoagulation With Unfractionated Heparin

Abstract

Objective The objective was to determine the proportion of patients with pulmonary embolism (PE) treated with unfractionated heparin (UFH) who achieved therapeutic activated partial thromboplastin time (aPTT) values within 48 hours of treatment. Methods Retrospective analysis of a PE response team (PERT) database was performed at a large, urban, academic teaching hospital. Inclusion criteria were adult patients with acute PE for whom the PERT was consulted and who received anticoagulation (AC) with UFH according to guideline standard dosing. aPTT values during 6‐hour time periods during the first 48 hours of AC were collected and analyzed. Results A total of 505 patients met inclusion criteria. For patients receiving a bolus and infusion of UFH, the proportions (95% confidence interval [CI]) of patients in the therapeutic range were 19.0% (14.2% to 25.0%) at 12 hours, 26.3% (26.3% to 33.1%) at 24 hours, 28.3% (22.0% to 35.4%) at 36 hours, and 28.4% (20.8% to 37.5%) at 48 hours. For titrated infusion only, the proportions (95% CIs) of patients were 23.3% (16.2% to 32.3%) at 12 hours, 41.4% (31.6% to 51.9%) at 24 hours, 37.0% (26.8% to 48.5%) at 36 hours, and 42.1% (30.2% to 55.0%) at 48 hours. No patient had all therapeutic aPTT values. Conclusions The majority of patients with acute PE spend most of their first 48 hours outside of the therapeutic range of AC when treated with guideline standard dosing of UFH. Over half of the patients fail to achieve any therapeutic PTT level within 24 hours of UFH initiation, and no patient had all therapeutic aPTTs. Future research should focus on identifying factors associated with achieving therapeutic AC with UFH.

Case 18-2021: An 81-Year-Old Man with Cough, Fever, and Shortness of Breath

“…However, the use of dose-adjusted unfractionated heparin often fails to achieve a therapeutic effect on the activated partial-thromboplastin time within 48 hours after initiation. 22 Low-molecular-weight heparin at a weight-based dose is more biologically predictable and is associated with a lower risk of additional thrombus formation and bleeding, as well as smaller thrombi, than dose-adjusted intravenous unfractionated heparin. 23 The use of up-front direct oral anticoagulant agents (factor II and X inhibitors) is also appropriate for patients with lower-risk pulmonary embolism.…”

Safety of Therapeutic Anticoagulation with Low-Molecular-Weight Heparin or Unfractionated Heparin Infusion during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism

“…This needs to be further investigated in larger studies, as the LMWH subgroup reported here might have been too small to detect rare complications. In a study evaluating the ability to reach therapeutic partial thromboplastin time with unfractionated heparin infusion in 505 patients with acute PE, 60.6% of patients were subtherapeutic 48 hours after initiation of therapy, 11% were supratherapeutic, and only 28.4% were within therapeutic range (60-80 seconds) (19). Prucnal et al (19) also postulate that treatment with heparin infusion is often justified by the potential need for advanced treatment (ie, endovascular intervention).…”

“…In a study evaluating the ability to reach therapeutic partial thromboplastin time with unfractionated heparin infusion in 505 patients with acute PE, 60.6% of patients were subtherapeutic 48 hours after initiation of therapy, 11% were supratherapeutic, and only 28.4% were within therapeutic range (60-80 seconds) (19). Prucnal et al (19) also postulate that treatment with heparin infusion is often justified by the potential need for advanced treatment (ie, endovascular intervention). Overall, LMWH and heparin at a full therapeutic dose appear to be safe during CDT, although it is not currently endorsed by the Society of Interventional Radiology (20).…”

“…Information regarding the duration needed to achieve the target partial thromboplastin time for the heparin group, or regarding missed doses in the LMWH group, could not be verified for the current cohort. This might confound the complication and effectiveness results as patients might have been over-or under-coagulated during the course of their treatment (19). Regression analysis evaluating variables that might contribute to higher risk of hemorrhagic complications was not performed owing to the overall low number of complications.…”

Antithrombotische Therapie bei Lungenembolie

“…1 Therapeutische Antikoagulation von Patienten mit Lungenembolie 1. oder UFH oder Fondaparinux 2. Dabigatran 110 mg 2-mal täglich bei Alter ≥ 80 Jahre oder gleichzeitiger Behandlung mit Verapamil 3.…”