Effect of Short Procedural Duration With Bivalirudin on Increased Risk of Acute Stent Thrombosis in Patients With STEMI: A Secondary Analysis of the HORIZONS-AMI Randomized Clinical Trial

Bioinspired Vascular Stents with Microfluidic Electrospun Multilayer Coatings for Preventing In-Stent Restenosis

In-stent restenosis (ISR) is seriously affecting the long-term prognosis of vascular interventional therapy and leading to enormous medical burdens. Great efforts have been devoted to developing functional vascular stents with desired features and properties for effective ISR prevention. Here, a multifunctional bionic vascular stent with designed coatings prepared using microfluidic electrospinning technology is presented. Such stents are composed of biocompatible, drug-loaded methylacrylated gelatin-polyethylene glycol diacrylate (GelMA-PEGDA) and polycaprolactone composite nanofibers on 316L stainless steel stents by an easy-to-operate step-by-step spraying method. Benefitting from the addition of polydopamine during the fabrications, the drug-loaded composite nanofibers can adhere well to both the stent and the vascular wall. Furthermore, as the inner fibrous layer of the stent contacting the lumen is equipped with heparin-vascular endothelial growth factor (Hep-VEGF), it plays an anticoagulation role and promotes the growth of endothelial cells; while the outer layer contacts the vascular wall and releases rapamycin slowly, which can restrain smooth muscle proliferation. By implanting this into the rabbit carotid artery, the multi-functional bionic demonstrates that the vascular stent can achieve good anti-thrombosis and in-stent restenosis effects, which indicates its potential values in vascular intervention and other biomedical fields.

Coronary Angioplasty and Stenting in Acute Coronary Syndromes Using Very Low Contrast Volume and Radiation Dosage Improves Renal and Cardiovascular Outcomes

Aim: To demonstrate that in patients with acute coronary syndrome (ACS), using Cordis 6F Infiniti diagnostic catheters for angioplasty may represent a safe alternative associated with lower contrast volume and radiation dosage, improving cardiovascular and renal outcomes.

Material and Methods: In 1,800 patients with ACS (2,331 lesions/2,603 stents), angioplasty was performed with Cordis 6F Infiniti Thrulumen diagnostic catheters. Primary angioplasty was performed in 545 cases, and only balloon angioplasty in 67 patients. All procedures were performed through the femoral route, and switch-over to the radial route was made in 5 cases due to associated aortic/iliac obstructive lesions. Iodixanol was used in 76% of cases, and tirofiban in 99% of cases with adjusted dosages based on creatinine values. The mean contrast volume used per patient was 28 mL (± 6 mL) including the angiogram prior to the angioplasty.

Results: The median fluoroscopy time was 4.4 min (IQR 3–6.8), the mean fluoroscopy time was 5.59 min (± 0.28), the median dose-area product or kerma-area product was 1,507 µGym2 (IQR 918–2,611), median total or cumulative dose including backscatter was 2,702 µGym2 (IQR 1,805–4,217), and the median cumulative skin dose was 468 mGy (IQR 296–722). Groin hematoma was seen in 7 cases, proximal mild edge dissection in the deployed stent in 3 cases, and acute in-hospital stent thrombosis in 7 cases. In total, 33 deaths were registered and 19 of these patients had cardiogenic shock, of which 11 subjects were late presenters. Three patients died after discharge due to possible acute stent thrombosis.

Conclusions: Angioplasty and stenting can be performed safely in patients with acute coronary syndromes using Cordis 6F diagnostic catheters. The procedure was associated with a very low volume of contrast and radiation dose, leading to improved clinical outcomes..

Anticoagulation in ST-Elevation Myocardial Infarction

Intravenous anticoagulation is standard of care in the treatment of ST-elevation myocardial infarction. Primary percutaneous coronary intervention is the most common reperfusion strategy. Four anticoagulant options are available: unfractionated heparin, enoxaparin, fondaparinux, and bivalirudin. This article discusses the mechanism of action and key pharmacodynamic characteristics of these agents. The evolution of outcomes with unfractionated heparin compared with bivalirudin in the changing landscape of contemporary percutaneous coronary intervention is chronicled. Current anticoagulation recommendations from practice guidelines are provided and unresolved issues including treatment of patient subsets such as women and chronic kidney disease are explored.

Self-regulated hirudin delivery for anticoagulant therapy

Pathological coagulation, a disorder of blood clotting regulation, induces a number of cardiovascular diseases. A safe and efficient system for the delivery of anticoagulants to mimic the physiological negative feedback mechanism by responding to the coagulation signal changes holds the promise and potential for anticoagulant therapy. Here, we exploit a "closed-loop" controlled release strategy for the delivery of recombinant hirudin, an anticoagulant agent that uses a self-regulated nanoscale polymeric gel. The cross-linked nanogel network increases the stability and bioavailability of hirudin and reduces its clearance in vivo. Equipped with the clot-targeted ligand, the engineered nanogels promote the accumulation of hirudin in the fibrous clots and adaptively release the encapsulated hirudin upon the thrombin variation during the pathological proceeding of thrombus for potentiating anticoagulant activity and alleviating adverse effects. We show that this formulation efficiently prevents and inhibits the clot formation on the mouse models of pulmonary embolism and thrombosis.

Antithrombotic efficacy of bivalirudin compared to unfractionated heparin during percutaneous coronary intervention for acute coronary syndrome

Bivalirudin is associated with an increased risk of acute stent thrombosis (AST) compared to unfractionated heparin (UFH) in acute coronary syndrome patients (ACS) during short-duration percutaneous coronary intervention (PCI). The mechanisms involved are unknown. We aimed to investigate the antithrombotic efficacy of bivalirudin compared to UFH during PCI. In a monocenter study, we prospectively enrolled 30 patients undergoing PCI for a non-ST elevation ACS. They were randomly assigned to a single intravenous (IV) bolus of UFH (70 IU/kg) or an IV bolus of bivalirudin 0.75 mg/kg followed by a 1.75 mg/kg/h infusion during PCI. All patients received a loading dose (LD) of 180 mg of ticagrelor at the time of PCI. The VASP index and activated partial thromboplastin time (aPTT) were used to assess the course of platelet reactivity (PR) and antithrombotic activity. The two groups were similar regarding baseline, angiographic, and interventional characteristics. There was no difference between the two groups in the course of PR following ticagrelor LD. An optimal PR inhibition was obtained 4 h after the LD of ticagrelor. The level of antithrombotic activity was significantly lower in the bivalirudin group compared to the UFH group (p < 0.001) during PCI but similar at 2 and 4 h post-PCI. We observed that, in ACS undergoing PCI, the antithrombotic efficacy of an IV bolus of bivalirudin is significantly lower than that of a 70-IU/kg UFH bolus. This could contribute to the excess in thrombotic acute events observed during short-duration PCI.