Effect of Optison on pulmonary artery systolic pressure and pulmonary vascular resistance

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

Safety of Lumason® (SonoVue®) in special populations and critically ill patients

Evidence for the safe use of Lumason® (SonoVue®), an ultrasound enhancing agent (UEA), in special patient populations is critical to enable healthcare professionals to make informed decisions concerning its use in such patients. Herein, we provide insight on the safety and tolerability of Lumason® in special patient populations. Findings are presented from clinical pharmacology studies conducted in patients with compromised cardiopulmonary conditions, from a retrospective study performed in critically ill patients, and from post-marketing surveillance data from over 20 years of market use of Lumason® (SonoVue®). No detrimental effects of Lumason® on cardiac electrophysiology were observed in patients with coronary artery disease (CAD), and no significant effects on pulmonary hemodynamics were noted in patients with pulmonary hypertension or congestive heart failure. Similarly, no effects on several assessments of pulmonary function (e.g., FVC) were observed in patients with chronic obstructive pulmonary disease (COPD), and no clinically meaningful changes in O2 saturation or other safety parameters were observed after administration of Lumason® to patients with diffuse interstitial pulmonary fibrosis (DIPF). The retrospective study of critically ill patients revealed no significant difference for in-hospital mortality between patients administered Lumason® for echocardiography versus those who had undergone echocardiography without contrast agent. Post-marketing surveillance revealed very low reporting rates (RR) for non-serious and serious adverse events and that serious hypersensitivity reactions were rare. These findings confirm that Lumason® is a safe and well tolerated UEA for use in special populations and critically ill patients.

A review of the safety and clinical utility of contrast echocardiography

There are limitations to the sensitivity and specificity of conventional two-dimensional echocardiograms in making an accurate diagnosis in certain patient populations. This led to the development of specific contrast-enhancing agents with the following characteristics: small enough to cross the pulmonary capillary bed, remain stable throughout the length of the procedure, do not dissolve in blood, and rapidly cleared from the body with low toxicity. Unfortunately, the use of contrast echocardiography has not taken off as expected. The low take-up rate among clinicians can largely be attributed to the black box warning by the United States Food and Drug Administration in 2007, after the coincidental occurrence of four patient deaths and about 190 severe cardiopulmonary reactions shortly after contrast agent administration. In this article, we address the clinical safety of contrast agents, share our institution's experience in using it and elaborate on the clinical indications of contrast echocardiography.

Clinical practice of contrast echocardiography: recommendation by the European Association of Cardiovascular Imaging (EACVI) 2017

Contrast echocardiography is widely used in cardiology. It is applied to improve image quality, reader confidence and reproducibility both for assessing left ventricular (LV) structure and function at rest and for assessing global and regional function in stress echocardiography. The use of contrast in echocardiography has now extended beyond cardiac structure and function assessment to evaluation of perfusion both of the myocardium and of the intracardiac structures. Safety of contrast agents have now been addressed in large patient population and these studies clearly established its excellent safety profile. This document, based on clinical trials, randomized and multicentre studies and published clinical experience, has established clear recommendations for the use of contrast in various clinical conditions with evidence-based protocols.

Characteristics and Echogenicity of Clinical Ultrasound Contrast Agents: An In Vitro and In Vivo Comparison Study

OBJECTIVES

To compare physicochemical characteristics and in vitro and in vivo contrast-enhanced ultrasound imaging performance of 3 commercially available ultrasound contrast agents: SonoVue (Bracco Imaging SpA, Colleretto Giacosa, Italy; also marketed as Lumason in the USA), Definity (Lantheus Medical Imaging, North Billerica, MA) and Optison (GE Healthcare AS, Oslo, Norway).

METHODS

Physicochemical characteristics were measured with a Multisizer Coulter Counter (Beckman Coulter, Fullerton, CA). Two ultrasound systems (Aplio 500; Toshiba Medical Systems Corp, Tochigi-ken, Japan; and Logiq E9; GE Healthcare, Little Chalfont, England) were used with different transducers. Contrast enhancement was measured in vitro by dose-ranging measurements using a custom-built beaker setup; in vivo imaging performances were compared in pigs (heart and liver) and rabbits (liver). Quantitative analyses were performed with VueBox quantification software (Bracco Suisse SA, Plan-les-Ouates, Switzerland).

RESULTS

Measured physicochemical characteristics were in agreement with those provided by the manufacturers. In vitro data demonstrated that the performance of SonoVue was similar to or better than that of Definity but superior to Optison (normalized scattered power 2- to 10-fold higher with SonoVue). Similar results were obtained in vivo, although the duration of enhancement in the pig heart was longer for SonoVue compared to Definity, and quantitative analysis revealed higher enhancement for SonoVue (1.5-fold increase). For liver imaging, SonoVue and Definity showed similar contrast enhancement and duration of enhancement, but compared to Optison, both peak enhancement and duration of enhancement were superior for SonoVue (up to 2-fold increase).

CONCLUSIONS

Imaging performance of SonoVue was similar to or slightly better than that of Definity, but it was superior to Optison for the conditions used in this study.

Safety With Echocardiographic Contrast Agents

In October 2007, the Food and Drug Administration mandated significant revisions to product labeling for the commercially available echocardiographic contrast agents (ECA) Definity and Optison after spontaneous healthcare provider reports of 4 patient deaths and ≈190 severe cardiopulmonary reactions occurring in close temporal relationship to ECA administration. Since then, multiple large ECA safety studies have been published and have included outpatients, hospitalized patients (including the critically ill), patients undergoing stress echocardiography, and patients with pulmonary hypertension. In addition, the Food and Drug Administration has convened 2 Advisory Committee meetings and the product labels for Optison and Definity have been substantially revised with a softening of safety restrictions. In this review, we will address the safety of ECA use in patients with serious cardiopulmonary conditions, patients with intracardiac shunts, and special patient populations including pulmonary hypertension, pediatrics, and pregnancy. In addition, we will discuss the confounding role of pseudocomplication in attribution of adverse events during diagnostic testing, the current status of the ECA Black Box Warning, and recommended safety precautions during ECA administration.

Update on the safety and efficacy of commercial ultrasound contrast agents in cardiac applications

Ultrasound contrast agents (UCAs) are currently used throughout the world in both clinical and research settings. The concept of contrast-enhanced ultrasound imaging originated in the late 1960s, and the first commercially available agents were initially developed in the 1980s. Today's microbubbles are designed for greater utility and are used for both approved and off-label indications. In October 2007, the US Food and Drug Administration (FDA) imposed additional product label warnings that included serious cardiopulmonary reactions, several new disease-state contraindications, and a mandated 30 min post-procedure monitoring period for the agents Optison and Definity. These additional warnings were prompted by reports of cardiopulmonary reactions that were temporally related but were not clearly attributable to these UCAs. Subsequent published reports over the following months established not only the safety but also the improved efficacy of clinical ultrasound applications with UCAs. The FDA consequently updated the product labeling in June 2008 and reduced contraindications, although it continued to monitor select patients. In addition, a post-marketing program was proposed to the sponsors for a series of safety studies to further assess the risk of UCAs. Then in October 2011, the FDA leadership further downgraded the warnings after hearing the results of the post-marketing data, which revealed continued safety and improved efficacy. The present review focuses on the use of UCAs in today's clinical practice, including the approved indications, a variety of off-label uses, and the most recent data, which affirms the safety and efficacy of UCAs.

Feasibility and Diagnostic Potential of Pulmonary Transit Time Measurement by Contrast Echocardiography: A Pilot Study

AIMS

Pulmonary transit time (PTT; the time for ultrasound contrast to travel from the right ventricle [RV] to the left atrium) may provide a single metric that reports on cardiopulmonary function while overcoming some of the challenges of standard echocardiographic measures. We conducted a pilot study to test the feasibility and reproducibility of echocardiographically derived PTT and to determine its association with established measures of cardiopulmonary function.

METHODS AND RESULTS

A total of 39 patients receiving clinically indicated ultrasound contrast were prospectively enrolled. PTT was measured in the apical four-chamber view using commercially available software. Reproducibility and inter-observer agreement were assessed in 9 patients. PTT was correlated with established measures of left ventricular systolic and diastolic function, RV function, and pulmonary vascular status. PTT could be measured in 89% (33/37) of patients without a contraindication to ultrasound contrast; all measurements from the last 20 patients were interpretable and obtained independently by a sonographer. Reproducibility and inter-observer agreement were excellent. PTT correlated well with standard echocardiographic indicators of cardiac status. A PTT >4.5 seconds accurately identified all but 1 patient with cardiopulmonary dysfunction.

CONCLUSIONS

This pilot study demonstrates that measurement of PTT using ultrasound contrast is highly reproducible, accurately reflects global cardiopulmonary function across a range of cardiopulmonary disease, and can be readily obtained by an independent sonographer. Further studies are needed to determine whether PTT has incremental value in diagnosis and prognosis compared to conventional echocardiographic parameters.