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

Thromboprophylaxis with argatroban in critically ill patients with sepsis: a review

During sepsis, an initial prothrombotic shift takes place, in which coagulatory acute-phase proteins are increased, while anticoagulatory factors and platelet count decrease. Further on, the fibrinolytic system becomes impaired, which contributes to disease severity. At a later stage in sepsis, coagulation factors may become depleted, and sepsis patients may shift into a hypo-coagulable state with an increased bleeding risk. During the pro-coagulatory shift, critically ill patients have an increased thrombosis risk that ranges from developing micro-thromboses that impair organ function to life-threatening thromboembolic events. Here, thrombin plays a key role in coagulation as well as in inflammation. For thromboprophylaxis, low molecular weight heparins (LMWH) and unfractionated heparins (UFHs) are recommended. Nevertheless, there are conditions such as heparin resistance or heparin-induced thrombocytopenia (HIT), wherein heparin becomes ineffective or even puts the patient at an increased prothrombotic risk. In these cases, argatroban, a direct thrombin inhibitor (DTI), might be a potential alternative anticoagulatory strategy. Yet, caution is advised with regard to dosing of argatroban especially in sepsis. Therefore, the starting dose of argatroban is recommended to be low and should be titrated to the targeted anticoagulation level and be closely monitored in the further course of treatment. The authors of this review recommend using DTIs such as argatroban as an alternative anticoagulant in critically ill patients suffering from sepsis or COVID-19 with suspected or confirmed HIT, HIT-like conditions, impaired fibrinolysis, in patients on extracorporeal circuits and patients with heparin resistance, when closely monitored.

Temporal Analysis of Tachycardia During Catheter Directed Thrombolysis for Acute Pulmonary Embolism

PURPOSE

To evaluate the effect of catheter directed thrombolysis (CDT) on heart rate (HR) in patients with sinus tachycardia and acute pulmonary embolism (PE).

METHODS

A retrospective chart review was performed for patients who underwent CDT with tPA for acute massive or submassive PE between 12/2009 and 2/2020. Included were patients who presented with tachycardia at the time of initiation of CDT. Patients with chronic PE, atrial fibrillation, beta blocker therapy, adjunctive endovascular therapy, systemic thrombolysis, or who expired before conclusion of CDT were excluded. HR was measured approximately every hour during CDT. Graphs were plotted of HR as a function of CDT duration. Two interventional radiologists identified the point of plateau (POP) on the graph where CDT had maximized its benefit in decreasing the patient's HR. Discrepancies were adjudicated by a third interventional radiologist and the median of the 3 measurements was selected. The primary endpoint was the duration of CDT from initiation until the POP.

RESULTS

48 patients were included (52.5 ± 14.7 years, 56.3% female). The POP occurred after 13.1 ± 6.1 hours, by which point HR had been reduced from 110 ± 9.2 bpm to 88 ± 10.6 bpm. Sinus tachycardia was not resolved in 10 patients even though they achieved maximal improvement in HR after 11.3 ± 6.7 hours.

CONCLUSION

Patients presenting with sinus tachycardia related to acute PE achieved maximal, sustained reduction in heart rate from CDT, after approximately 13 hours of infusion. Patients who did not resolve their tachycardia by that point in time were unlikely to resolve it by the conclusion of CDT.

Feasibility of anticoagulation using low molecular-weight heparin during catheter-directed thrombolysis for lower extremity deep venous thrombosis

Background

The optimal anticoagulant scheme during catheter-directed thrombolysis (CDT) for deep venous thrombosis (DVT) remains unknown. This study was performed to evaluate the feasibility of anticoagulation therapy using low molecular-weight heparin (LMWH) during CDT for DVT.

Methods

The clinical data of DVT patients who underwent CDT during the past six years was retrospectively collected and reviewed. Patients were divided into therapeutic-dose anticoagulation (TPDA) and sub therapeutic-dose anticoagulation (sub-TPDA) groups according to LMWH dosage.

Results

A total of 61 patients involving 61 limbs were comprised. Acute and subacute DVT were identified in 39 (63.9%) and 22 (36.1%) patients, respectively. Thrombosis involving the iliac vein was identified in 34 (55.7%) patients. Inferior vena cava filter placement was performed in 38 (62.3%) patients. Intraoperatively, adjunctive balloons, stents, and thrombectomy were provided for nine (14.8%), four (6.6%), and one (1.6%) patients, respectively. Twenty (32.8%) patients accepted TPDA therapy, while 41 (67.2%) patients were administrated with sub-TPDA therapy. Median urokinase infusion rate was 2.5 (0.83 to 5) × 10⁴ U/h. Median infusion duration time was 4 (2 to 14) days, and median urokinase dose infused was 2.4 (0.6 to 10.80) × 10⁶ U. During CDT, five (8.2%) cases of minor bleeding were observed, and blood transfusion was not required. No major bleeding, symptomatic pulmonary embolisms, or death occurred. Complete (> 90%) and partial thrombolysis (50 ~ 90%) were achieved in 56 (91.8%) patients. In comparison with sub-TPDA group, TPDA group exhibited no significant differences in baseline characteristics, clinical improvement, thrombolysis results, and complications.

Conclusions

Anticoagulation therapy using low molecular-weight heparin during CDT with low infusion rate for DVT is likely to be feasible and safe. Sub-therapeutic-dose anticoagulation and therapeutic-dose could be used for CDT with similar clinical outcome and bleeding complications.

The PERT Concept: A Step-by-Step Approach to Managing Pulmonary Embolism

Pulmonary embolism (PE) is a major source of morbidity and mortality. The presentation of acute PE varies, ranging from few or no symptoms to sudden death. Patient outcome depends on how well the right ventricle can sustain the increased afterload caused by the embolic burden. Careful risk stratification is critical, and the PE response team (PERT) concept offers a rapid and multidisciplinary approach. Anticoagulation is essential unless contraindicated; thrombolysis, surgical embolectomy, and catheter-directed approaches are also available. Clinical consensus statements have been published that offer a guide to PE management, but areas remain for which the evidence is inadequate. Although the management of low-risk and high-risk patients is more straightforward, optimal management of intermediate-risk patients remains controversial. In this document, we offer a case-based approach to PE management, beginning with diagnosis and risk stratification, followed by therapeutic alternatives, and finishing with follow-up care.

A Prospective Pilot Trial to Assess the Efficacy of Argatroban (Argatra®) in Critically Ill Patients with Heparin Resistance

The current study aims to evaluate whether prophylactic anticoagulation using argatroban or an increased dose of unfractionated heparin (UFH) is effective in achieving the targeted activated partial thromboplastin time (aPTT) of more than 45 s in critically ill heparin-resistant (HR) patients. Patients were randomized either to continue receiving an increased dose of UFH, or to be treated with argatroban. The endpoints were defined as achieving an aPTT target of more than 45 s at 7 h and 24 h. This clinical trial was registered on clinicaltrials.gov (NCT01734252) and on EudraCT (2012-000487-23). A total of 42 patients, 20 patients in the heparin and 22 in the argatroban group, were included. Of the patients with continued heparin treatment 55% achieved the target aPTT at 7 h, while only 40% of this group maintained the target aPTT after 24 h. Of the argatroban group 59% reached the target aPTT at 7 h, while at 24 h 86% of these patients maintained the targeted aPTT. Treatment success at 7 h did not differ between the groups (p = 0.1000), whereas at 24 h argatroban showed significantly greater efficacy (p = 0.0021) than did heparin. Argatroban also worked better in maintaining adequate anticoagulation in the further course of the study. There was no significant difference in the occurrence of bleeding or thromboembolic complications between the treatment groups. In the case of heparin-resistant critically ill patients, argatroban showed greater efficacy than did an increased dose of heparin in achieving adequate anticoagulation at 24 h and in maintaining the targeted aPTT goal throughout the treatment phase.