ExTRACT-TIMI 25 trial: clarifying the role of enoxaparin in patients with ST-elevation myocardial infarction receiving fibrinolysis

Update on the Pharmacological Actions of Enoxaparin in Nonsurgical Patients

Low-molecular-weight heparins are a class of drugs derived from the enzymatic depolymerization of unfractionated heparin that includes enoxaparin. Several studies have been performed on enoxaparin in recent years, in particular for the prevention and treatment of venous thromboembolism and for the treatment of acute coronary syndrome. Furthermore, the use of enoxaparin has been extended to other clinical situations that require antithrombotic pharmacological prevention, such as hemodialysis and recurrent abortion. In this review, we report the main clinical experiences of using enoxaparin in the prevention of VTE in nonsurgical patients.

Features of Parenteral Anticoagulant Therapy in Patients With Myocardial Infarction According to the Russian Register of Acute Myocardial Infarction – REGION-IM

Aim      To study specific features of the parenteral anticoagulant therapy for acute myocardial infarction (MI) in the Russian Federation and to evaluate the consistency of the prescribed parenteral anticoagulant therapy with the effective clinical guidelines.

Material and methods  REGION-MI, the Russian rEGIstry for acute myOcardial iNfarction, is a multicenter observational study. This registry includes all patients admitted to hospitals with a documented diagnosis of ST-elevation acute MI (STEMI) and non-ST-elevation acute MI (NSTEMI) based on the criteria of the Forth Universal Definition of MI of the European Society of Cardiology. Risk of bleeding was assessed with the Academic Research Consortium for High Bleeding Risk (ARC-HBR) scale, and risk of major bleeding in patients with NSTEMI was additionally assessed with the CRUSADE scale.

Results From November 01, 2020 through April 03, 2022, 5025 patients were included into the REGION-MI registry. At primary vascular departments, 70.5% of patients were administered unfractionated heparin (NFH); at regional vascular centers, 37.1 % of patients were administered NFH, 29.6 % enoxaparin, 20,2% NFH in combination with enoxaparin, 6.8 % fondaparinux, 4.2 % NFH in combination with fondaparinux, and 1.9 % nadroparin. At the prehospital stage, NFH was used as an anticoagulant support for the thrombolytic therapy (TLT) in 84% of patients, and low-molecular heparins (LMH) were used in 16 %. At the hospital stage, UFH was administered to 64.4 % of patients, and enoxaparin was administered to 23.9 % of patients. Among the patients who had undergone primary percutaneous coronary intervention (PCI), 40 % received NFH, 25 % enoxaparin, 22 % NFH in combination with enoxaparin, 7 % fondaparinux, and 4 % NFH in combination with fondaparinux. In conservative and invasive tactics of therapy for NSTEMI, NFH was also administered more frequently (43 and 43 %, respectively), followed by (according to frequency of administration) enoxaparin (36 and 34 %, respectively), NFH in combination with enoxaparin (10 and 16 %, respectively), fondaparinux (7 and 6 %, respectively), and NFH in combination with fondaparinux (3 and 1 %, respectively).

Conclusion      According to the Russian registry of acute MI, REGION-MI, with all strategies for the treatment of MI, parenteral anticoagulants are not prescribed in full consistency with clinical guidelines. The most frequently used parenteral anticoagulant is NFH. Despite the high efficacy and safety of fondaparinux, the frequency of its administration remains unjustifiably low not only in the Russian Federation but also in other countries. The same can be said about the administration of enoxaparin to patients who had received TLT. Attention should be paid to physicians’ awareness of recent clinical guidelines, to minimize the prehospital treatment with parenteral anticoagulants, to limit this treatment to the TLT support, and to provide continuity between all stages of medical care.

Upfront thrombus aspiration in primary coronary intervention for patients with ST-segment elevation acute myocardial infarction: report of the VAMPIRE (VAcuuM asPIration thrombus REmoval) trial

OBJECTIVES

This study evaluated safety and efficacy of upfront thrombus aspiration during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Distal embolization during primary PCI results in reduced myocardial perfusion and poor clinical outcomes.

METHODS

The VAMPIRE (VAcuuM asPIration thrombus REmoval) study was a prospective, randomized, controlled multicenter trial conducted in 23 institutions. Patients (N = 355) presenting within 24 h of STEMI symptoms onset were randomized to primary PCI with (n = 180) or without (n = 175) upfront thrombus aspiration using Nipro's TransVascular Aspiration Catheter (Osaka, Japan).

RESULTS

The TransVascular Aspiration Catheter reached the lesion in 100% of cases. It successfully crossed the target obstruction in 86% without any delay in procedure time or time to reperfusion; whereas macroscopic thrombi were removed in 75% of the cases. Procedure success was similar between groups (98.9% vs. 98.3%). There was a trend toward lower incidence of slow or no reflow (primary end point-defined as a Thrombolysis In Myocardial Infarction flow grade <3) in patients treated with aspiration versus conventional primary PCI (12.4% vs. 19.4%, p = 0.07). Rate of myocardial blush grade 3 was higher in the aspiration group (46.0% vs. 20.5%, p < 0.001). Aspiration was most effective in patients presenting after 6 h of symptoms onset (slow flow rate: 8.1% vs. 37.6%, p = 0.01).

CONCLUSIONS

This study suggested the safety of primary PCI with upfront thrombectomy using a novel device in patients with STEMI. The study showed a trend toward improved myocardial perfusion and lower clinical events in patients treated with aspiration. Patients presenting late after STEMI appear to benefit the most from thrombectomy.