Engineering 3D Printed Microfluidic Chips for the Fabrication of Nanomedicines.

Currently, there is an unmet need to manufacture nanomedicines in a continuous and controlled manner. Three-dimensional (3D) printed microfluidic chips are an alternative to conventional PDMS chips as they can be easily designed and manufactured to allow for customized designs that are able to reproducibly manufacture nanomedicines at an affordable cost. The manufacturing of microfluidic chips using existing 3D printing technologies remains very challenging because of the intricate geometry of the channels. Here, we demonstrate the manufacture and characterization of nifedipine (NFD) polymeric nanoparticles based on Eudragit L-100 using 3D printed microfluidic chips with 1 mm diameter channels produced with two 3D printing techniques that are widely available, stereolithography (SLA) and fuse deposition modeling (FDM). Fabricated polymeric nanoparticles showed good encapsulation efficiencies and particle sizes in the range of 50-100 nm. SLA chips possessed better channel resolution and smoother channel surfaces, leading to smaller particle sizes similar to those obtained by conventional manufacturing methods based on solvent evaporation, while SLA manufactured nanoparticles showed a minimal burst effect in acid media compared to nanoparticles fabricated with FDM chips. Three-dimensional printed microfluidic chips are a novel and easily amenable cost-effective strategy to allow for customization of the design process for continuous manufacture of nanomedicines under controlled conditions, enabling easy scale-up and reducing nanomedicine development times, while maintaining high-quality standards.

Use of antithrombotic therapy for secondary prevention in patients with stable atherosclerotic cardiovascular disease: Insights from the COordinated National Network to Engage Cardiologists in the antithrombotic Treatment of patients with CardioVascular Disease (CONNECT-CVD) study.

BACKGROUND: Although acetylsalicylic acid is the most commonly used antithrombotic agent for the secondary prevention of cardiovascular events, residual atherothrombotic risk has prompted a guideline recommendation for the addition of dual antiplatelet therapy (DAPT) or dual pathway inhibition (DPI) in high vascular risk patients. Accordingly, the CONNECT CVD quality enhancement initiative provides a contemporary "snapshot" of the clinical features and antithrombotic management of atherosclerotic cardiovascular disease (ASCVD) patients in Canada. METHODS: Canadian cardiologists (49 cardiologists from six provinces) undertook a retrospective chart audit of 10 ASCVD patients in their outpatient practice who met the Cardiovascular Outcomes for People Using Anticoagulation Strategy-like criteria from May 2018 to April 2019. RESULTS: Of the 492 (two cardiologists provided 11 patients) enroled, average age was 70 years, 25% were female, 39% had diabetes and 20% had atrial fibrillation. Prior revascularisation was common (percutaneous coronary artery intervention 61%, coronary artery bypass graft 39%), with 31% having multivessel disease. A total of 47% of patients had a Reduction of Atherothrombosis for Continued Health bleeding score of ≥11 (~2.8% risk of serious bleeding at 2 years). Single antiplatelet therapy (SAPT) alone was most commonly used (62%), while 22% were on DAPT alone. In total, 22% were on oral anticoagulation (OAC), with 16% being on non-vitamin K oral anticoagulant alone, 5% on DPI and 1% received triple therapy. CONCLUSIONS: In contemporary Canadian clinical practice of stable ASCVD patients, a large number of patients receive antithrombotic therapy other than SAPT. Further efforts are required to guide the appropriate selection of patients in whom more potent antithrombotic therapies may safely reduce residual risk.

Helically arranged cross struts in azhdarchid pterosaur cervical vertebrae and their biomechanical implications.

Azhdarchid pterosaurs, the largest flying vertebrates, remain poorly understood, with fundamental aspects of their palaeobiology unknown. X-ray computed tomography reveals a complex internal micro-architecture for three-dimensionally preserved, hyper-elongate cervical vertebrae of the Cretaceous azhdarchid pterosaur, Alanqa sp. Incorporation of the neural canal within the body of the vertebra and elongation of the centrum result in a "tube within a tube" supported by helically distributed trabeculae. Linear elastic static analysis and linearized buckling analysis, accompanied with a finite element model, reveal that as few as 50 trabeculae increase the buckling load by up to 90%, implying that a vertebra without the trabeculae is more prone to elastic instability due to axial loads. Subsuming the neural tube into the centrum tube adds considerable stiffness to the cervical series, permitting the uptake of heavy prey items without risking damage to the cervical series, while at the same time allowing considerable skeletal mass reduction.

Personalised 3D Printed Medicines: Optimising Material Properties for Successful Passive Diffusion Loading of Filaments for Fused Deposition Modelling of Solid Dosage Forms.

Although not readily accessible yet to many community and hospital pharmacists, fuse deposition modelling (FDM) is a 3D printing technique that can be used to create a 3D pharmaceutical dosage form by employing drug loaded filaments extruded via a nozzle, melted and deposited layer by layer. FDM requires printable filaments, which are commonly manufactured by hot melt extrusion, and identifying a suitable extrudable drug-excipient mixture can sometimes be challenging. We propose here the use of passive diffusion as an accessible loading method for filaments that can be printed using FDM technology to allow for the fabrication of oral personalised medicines in clinical settings. Utilising Hansen Solubility Parameters (HSP) and the concept of HSP distances (Ra) between drug, solvent, and filament, we have developed a facile pre-screening tool for the selection of the optimal combination that can provide a high drug loading (a high solvent-drug Ra, >10, and an intermediate solvent-filament Ra value, ~10). We have identified that other parameters such as surface roughness and stiffness also play a key role in enhancing passive diffusion of the drug into the filaments. A predictive model for drug loading was developed based on Support Vector Machine (SVM) regression and indicated a strong correlation between both Ra and filament stiffness and the diffusion capacity of a model BCS Class II drug, nifedipine (NFD), into the filaments. A drug loading, close to 3% w/w, was achieved. 3D printed tablets prepared using a PVA-derived filament (Hydrosupport, 3D Fuel) showed promising characteristics in terms of dissolution (with a sustained release over 24 h) and predicted chemical stability (>3 years at 25 °C/60% relative humidity), similar to commercially available NFD oral dosage forms. We believe FDM coupled with passive diffusion could be implemented easily in clinical settings for the manufacture of tailored personalised medicines, which can be stored over long periods of time (similar to industrially manufactured solid dosage forms).

Providing Rapid Out of Hospital Acute Cardiovascular Treatment 4 (PROACT-4).

BACKGROUND: Whether prehospital point-of-care (POC) troponin further accelerates the time to diagnosis in patients with chest pain (CP) is unknown. We conducted a randomized trial of POC-Troponin testing in the ambulance. METHODS AND RESULTS: Patients with chest pain presenting by ambulance were randomized to usual care (UC) or POC-Troponin; ST-elevation myocardial infarction patients or those with noncardiovascular symptoms were excluded. Pre-hospital high-sensitivity troponin was analyzed on a POC device and available to the paramedic and emergency department (ED) staff. The final diagnosis was centrally adjudicated. The primary endpoint was time from first medical contact to discharge from ED or admission to hospital. We randomized 601 patients in 19 months; 296 to UC and 305 to POC-Troponin. After ambulance arrival, the first troponin was available in 38 minutes in POC-Troponin and 139 minutes in UC. In POC-Troponin, the troponin was >0.01 ng/mL in 17.4% and >0.03 ng/mL in 9.8%. Patients spent a median of 9.0 hours from first medical contact to final disposition, and 165 (27.4%) were admitted to the hospital. The primary endpoint was shorter in patients randomized to POC-Troponin (median 8.8 hours [6.2-10.8] compared to UC (median 9.1 hours [6.7-11.2]; P=0.05). There was no difference in the secondary endpoint of repeat ED visits, hospitalizations, or death in the next 30 days. CONCLUSIONS: In this broad population of patients with CP, ambulance POC-Troponin accelerated the time to final disposition. Enhanced and more cost-effective early ED discharge of the majority of patients with CP calling 911 is an unrealized opportunity. CLINICAL TRIAL REGISTRATION: URL: https://www.ClinicalTrials.gov/. Unique identifier: NCT01634425.

Providing Rapid Out of Hospital Acute Cardiovascular Treatment 3 (PROACT-3).

BACKGROUND: The outcomes of acute cardiovascular symptom presentations are potentially modifiable with the use of biomarkers to accelerate accurate diagnosis. This randomized trial tested troponin and B-type natriuretic peptide before hospital guidance in patients with acute cardiovascular symptoms. METHODS: Patients with either chest pain or shortness of breath were randomized to usual care or biomarkers analyzed using a point-of-care device in the ambulance. The primary end point was time to final disposition (discharge from the emergency department or admission to hospital). The trial was stopped prematurely because of less than expected enrollment of patients of interest and no difference in the primary end point. RESULTS: We randomized 491 patients; 480 formed the final cohort. Patients were 49% male; median age 70 years; 42% had previous acute coronary syndrome; and 28% diabetes. The B-type natriuretic peptide level before hospital arrival was ≥ 100 pg/mL in 36.4%. Troponin was > 0.03 ng/mL in 13.4%; 3.6% had troponin > 0.1 ng/mL. After adjudication, 16% had acute coronary syndrome, 6.5% acute heart failure, 3.3% angina, and 74.2% another diagnosis. The primary end point was 9.2 (interquartile range, 7.3-11.1) hours in the biomarker group and 8.8 (interquartile range, 6.3-12.1) hours in the usual care group (P = 0.6). None died in the ambulance or in the emergency department: all-cause 30-day mortality was 2.1% (usual care) and 1.7% (biomarker). CONCLUSIONS: To our knowledge, this is the first randomized trial of biomarkers before hospital arrival to guide emergency management of suspected acute cardiovascular disease which showed no benefit and was terminated early because of futility. The results have important implications for the use of biomarkers in emergency management of heart disease and for the design of future randomized trials on this important topic.

Biventricular apical thrombi demonstrated by contrast-enhanced cardiac MRI following anteroapical STEMI and unsuccessful reperfusion therapy.

Contrast-enhanced cardiac magnetic resonance imaging can define the territory and extent of myocardial infarction from patterns of late gadolinium enhancement. Following failure to reperfuse with thrombolytic therapy, a case of myocardial infarction is described in which ongoing symptoms and an electrocardiogram change led to a diagnostic dilemma. Cardiac magnetic resonance imaging confirmed an apical infarction, an aneurysm and acute pericarditis. In addition, late gadolinium enhancement unexpectedly revealed the presence of biventricular apical thrombi. The prevalence of cardiac thrombi and pulmonary emboli may be greater than generally appreciated.

Triggering of the Bezold Jarisch Reflex by reperfusion during primary PCI with maintenance of consciousness by cough CPR: a case report and review of pathophysiology.

This report documents a case of hemodynamic collapse during primary angioplasty (PCI) for acute inferior ST-segment elevation myocardial infarction (STEMI). The patient had stable vital signs during the initial angiogram which had demonstrated an occluded mid right coronary artery (RCA). There was no evidence of right ventricular infarction or heart block. Reperfusion arrhythmia did not occur. The case illustrates triggering of the Bezold Jarisch Reflex (BJR) not by occlusion but reperfusion. In addition, this report illustrates the use of cough cardiopulmonary resuscitation (cough-CPR) to maintain consciousness during the BJR. Cough-CPR has previously been reported as a temporizing mechanism during ventricular arrhythmia prior to electrical cardioversion. This primary PCI case puts into clinical context the findings of historical animal studies and compares with clinical observations made during trials of intracoronary thrombolytic therapy.

Technical failure to perform cardiac resynchronization therapy: use of cardiac magnetic resonance imaging techniques to clarify a left-sided superior vena cava and coronary sinus morphology.

The most common reason for failure to implant a left ventricular lead to deliver cardiac resynchronization therapy is the presence of unfavourable coronary venous anatomy. The present report illustrates the use of cardiac magnetic resonance imaging to delineate the anatomy of a left-sided superior vena cava in two patients in whom permanent cardiac pacing was unattainable.