Versatile gene delivery targeting via Ultrasound and gas Microbubbles

The COVID-19 crisis and the rapid development of highly effective mRNA vaccines opened a new era for gene therapy. While viral vectors were for a long time the only tool for efficient delivery, new non-viral vectors have recently emerged, spawning new opportunities (indications, tissues, etc.). A new one is set to take off thanks to its safety profile, its specificity toward tissues, and its versatility toward both genetic materials and indications. Gas-filled microbubbles (MB), clinically used as ultrasound (US) contrast agents, have proven their benefits in various animal models and clinical applications for targeted delivery of drugs/genes. Herein, we disclose the development of new MB formulations allowing the delivery of various genetic materials at a specific location under the control of an ultrasound probe. We set forth a study to elicit the expression of a foreign enzyme in a liver mouse model. To this aim, MB were systemically co-injected with a Luciferase pDNA (6 to 65 mug) in the tail vein, then Ultrasound were delivered at MB arrival in the liver. The effective pDNA transfection was observed by bioluminescence 24 hours after treatment. Mice were divided into three groups: pDNA alone;pDNA with US;pDNA with US and MBs (n >= 5). The use of our MB allowed increasing the signal up to 5 folds in comparison to the US alone. These results highlight the potential of MB plus US to efficiently deliver locally genetic material without any safety concerns.

Vascular Response to a Cardiac Rehabilitation Program Adapted for COVID-19

Background: Cardiac Rehabilitation (CR) is a supervised exercise and risk factor modification program for patients with cardiac conditions. Endothelial dysfunction is often present and is associated with worsening cardiac prognosis, and several studies have indicated that standard onsite CR has improved endothelial function in heart disease patients. However, during the COVID-19 pandemic, many CR programs transitioned to a virtual or hybrid model of care to increase safety of CR programs. Objective(s): The objective of this study was to determine vascular function of patients with coronary artery disease (CAD) measured before and after 4 months of outpatient CR using a virtual model of care. Method(s): Virtual CR included 1 virtual group session/week by videoconferencing and hybrid CR included 1 session/week (4 on-site and 12 virtual group sessions) for a total of 16 weeks. CAD patients (6 females, 4 males) mean age 68.1+/-7.5 years rested in a supine position to measure 1) brachial artery flow-mediated dilation (FMD), 2) microvascular function, and 3) augmentation index (AI) using ultrasound sonography (n=8) and an EndoPAT 2000 (n=9). Two patients completed virtual CR and the rest underwent hybrid CR. These measurements were obtained concurrently using an ultrasound transducer at the brachial artery proximal to a blood pressure cuff on the forearm with EndoPAT cuffs on the index fingers during 5-minute intervals of baseline, occlusion, and recovery. FMD results were analyzed using automated Cardiovascular Suite software. AI and Reactive Hyperemia Index (LnRHI) were determined using automatic analysis via the EndoPAT 2000. Anthropometrics, blood pressure, and food intake were recorded at each visit. Patients were advised to refrain from strenuous exercise, alcohol, caffeine, and highly saturated foods at least 12 hours prior to the study appointment. One tailed paired t-tests were conducted between baseline and completion. Result(s): Adherence to CR averaged 10.3+/-3.2 out of 16 sessions. FMD improved from (2.75+/-1.71% to 5.63+/-4.37%, p=0.048) while there was no improvement in AI (14.2+/-18.8 to 13.2+/-19.6, p=0.45) or LnRHI (0.56+/-0.12 to 0.52+/-0.20, p=0.24). Conclusion(s): While there was no improvement in LnRHI or AI after CR, FMD improved in CAD patients after 4 months of adapted CR. Our results indicate that while virtual and hybrid models of CR may not be sufficient for improving microvascular function and aortic stiffness in CAD, there is an improvement of endothelial function. Future studies should examine the effects of adherence, duration and exercise intensity within these alternative models of CR on aortic and microvascular improvements.

Bedside diaphragmatic ultrasound used to diagnose an unexpected cause of weaning difficulty in a patient with COVID-19 pneumonitis

Introduction: Diaphragm dysfunction has been described as being responsible for weaning failure with an incidence of 23-80%. It has also been associated with difficult weaning from mechanical ventilation, prolonged intensive care unit (ICU) stay and increased ICU and hospital mortality.1 This case report describes the use of bedside ultrasound to diagnose diaphragm dysfunction, assess the severity of dysfunction, refer to specialist care and monitor disease progression in patient with COVID-19 pneumonitis with difficulty weaning from mechanical ventilation. Main body: A 59 year-oldmale with no known past medical history was admitted to our ICU with respiratory failure due to COVID-19 pneumonitis. He had received continuous positive pressure ventilation with oxygen supplementation on the medical high dependency unit for 15 days prior to deteriorating and requiring invasive ventilation in ICU. In ICU, the patient was mandatory ventilated using lung protective ventilation strategies for 26 days before he was switched to pressure support ventilation for attempts to wean him from mechanical ventilation. During the initial phase of his ICU admission, he was severely hypoxaemic and required deep sedation as well as muscle relaxation for a total of 370 hours. Prone positioning was required on 4 occasions before he was stable in the supine position. Once attempts to liberate him from mechanical ventilation were being made, pressure support was gradually reduced along with PEEP and FiO2. Progress with this reduction in support was slow due to marked tachypnoea and a dyssynchronous respiratory pattern. It was also noted that he had poor air entry in his right base with corresponding right lower zone opacities on his chest x-ray. At this stage a bedside ultrasound was used to investigate the cause of weaning difficulty and consequently, the diagnosis of right diaphragmatic paralysis was made. This was a new finding, as his admission chest x-ray did not show a raised hemidiaphragm. This diagnosis led to an increased focus on physical rehabilitation and mobilisation with tolerance of his tachypnoea and respiratory pattern as we now appreciated this didn't represent ongoing underlying parenchymal lung disease. We also made a referral to the respiratory team in order to facilitate longer-term rehabilitation and follow up. The patient was successfully extubated after intense physical rehabilitation, post extubation he remained tachypnoeic and still required supplemental oxygen at the point of hospital discharge. A follow up diaphragm ultrasound 6 months after discharge did not show any improvement in the right diaphragmatic function, he remains dyspnoeic on exertion and still occasionally uses ambulatory supplemental oxygen. Conclusion: Ultrasound assessment revealed an unexpected cause of weaning difficulty in our patient that allowed us to individualise his weaning plan and rehabilitation. This case shows that bedside intensivist performed ultrasound can accurately evaluate diaphragmatic function in patients who are difficult to wean from mechanical ventilation. Brief description of ultrasound video: The diaphragm was scanned using low frequency curvilinear ultrasound probe. There is lack of diaphragmatic excursion and absent thickening of the right hemidiaphragm on subcostal and intercostal views. M-mode evaluation and 'sniff test' confirms diaphragmatic paralysis.

The use of wireless ultrasound probes for bedside venous line placement in COVID-19 patients

Aim: To report single centre experience with use of wireless ultrasound probe for bedside venous line placement in COVID-19 patients. Method: From October 2020 to September 2021, we performed venous catheter inser-tions in 209 patients with COVID-19. The procedure was done at the angiographic suite or bedside. One hundred seventy-six patients with COVID-19 underwent bedside venous line placement. There were 115 males and 61 fema-les with average age 74.9 years (from 16 to 96 years). We used two types wireless linear US probes: Clarius Scanner L7 HD (Clarius Mobile Health Corp, Vancouver, Kanada) or 4Echo LeapMed (Guide Imaging, Oostende, Belgie). Large 12.9-inch tablets (iPad Pro, Apple Inc, Cupertino, USA) were used to display the ultrasound image. The ECG was used to verify the tip position of central inserted central venous catheter and PICCs. Results: The venous line was successfully inserted in 172 (97.7 %) patients at the first attempt. Four patients underwent second procedure because of vein dissection in 2 patients and hematoma and vein spasm in 2 patients. All repeated procedures were successful. The most common venous lines we used were midline in 143 patients. The PICC was inserted in 26 patients and central venous catheter (including dialysis catheter) was placed in 7 patients. Conclusion: The use of wireless US probes is convenient for bedside venous line placement. The main advantage is simple manipulation, preservation of anti-epidemic conditions and easier probe’s dressing with sterile cover, because there is not cable between US probe and tablet.

Lung ultrasound in children

Lung ultrasound (LUS) plays an increasingly important role in the diagnosis of chest diseases, and it is often called “the stethoscope of the 21st century”. It is a quick, inexpensive, radiation-free tool with a point-of-care option allowing for safe screening and/or follow-up. This paper presents the scanning technique, normal lung image, detectable pathologies, and exemplary applications in different disorders. Although lung ultrasound is of particular importance for the diagnosis of pneumonia in children, it has not been included in official guidelines so far. Advantages of lung ultrasound and advances in medical technology should increase the popularity of this technique as a complement to physical examination.

Submassive pulmonary thromboembolism, post-COVID sequelae;with mechanical thrombus aspiration and accelerated thrombolysis by Ekos ultrasound with successful resolution

Introduction: Acute pulmonary thromboembolism is a pulmonary pathology that is becoming more frequent nowadays, the use of new mechanical and thrombolytic therapies has a significant impact on the cardiopulmonary prognosis. Case: A 41-year-old male, a retired military man, smoking, overweight, dyslipidemia, alcoholic liver disease, who attended the emergency department due to abrupt dyspnea, with tachycardia, chest pain, and syncope;the patient had tachycardia of 120 bpm, BP 90/60 mmHg and SO2 of 82%, with a history of COVID-19 infection, suspected of massive pulmonary embolism, it was decided to carry out computed tomography where a bilateral submassive pulmonary embolism was documented (Fig. 1A), it was proposed to perform systemic thrombolysis, however due to the risk of bleeding, it was decided to perform EKOS ultrasound directed thrombolysis. Baseline pulmonary angiography was performed with a large number of thrombi (Fig. 1B), distributed in both main right and left branches and deficient pulmonary filling of distal vessels, due to the large amount of thrombus, it was decided to perform manual thrombus aspiration, obtaining a large amount of thrombus (Fig. 1C), as well as thrombolysis in situ with Alteplase a dose of 1 mg/catheter/hour for 12 hours, with a total dose of 24 mg;Ultrasound probe was placed in both pulmonary arteries with the EKOS system (Fig. 1D). Results: Pulmonary angiography was performed 24 hours after the procedure, where no bleeding occurred and almost complete resolution of the thrombus was observed. The patient later with 92% SO2, without oxygen requirements, with HR 90 bpm, with no evidence of ventricular dysfunction, was discharged home with anticoagulation. Conclusion: Low dose fibrinolysis and thromboaspiration are considered, as well as the use of EKOS endovascular ultrasound, a safe and effective procedure, in the context of a patient with high-risk of bleeding, with favorable results that condition clinical and prognostic improvement.