Safety of dobutamine stress real-time myocardial contrast echocardiography

Possible Effects on Health of Ultrasound Exposure, Risk Factors in the Work Environment and Occupational Safety Review

Ultrasonic waves are mechanical waves with a frequency greater than 20,000 Hz. Ultrasonic waves are emitted by devices that are used in industry or that have a medical or aesthetic purpose. There is growing interest in the effect of ultrasound absorption on the human body, since people's exposure to these acoustic waves has increased considerably in recent years. There are more and more devices that emit ultrasounds used for different sanitary procedures, aesthetic treatments and industrial processes, creating more possibilities of ultrasound noise, and therefore an increased risk of occupational hazard and occupational danger. Experiments on animals have shown damage to internal organs from receiving different ultrasonic frequencies. The main task of this work was to organize and summarize recent studies on ultrasound to reflect the current state of this technique and establish a systematic basis for future lines of research. This work has allowed us to better understand the unknown field of these high frequencies of sound, and highlights the need to carry out more studies on the ultrasound emissions that can be absorbed by the human body to determine how this energy could affect humans by calculating the maximum dose of exposure and developing manuals for the use of ultrasound-emitting equipment to protect the health of workers and all people. It is necessary to develop regulations by public administrations to improve the protection of workers, health professionals, patients and all people in general for better occupational safety, indoor environmental quality and environmental health.

Safety of SF6(SonoVue®) Contrast Agent on Pharmacological Stress Echocardiogram

Fundamento

Em 2007, a Food and Drug Administration (FDA) determinou revisões sobre segurança dos agentes de contraste ecocardiográfico (ACE) disponíveis no mercado após relatos de mortes. Ao longo desses anos, diversos estudos comprovaram a segurança dos ACE, porém com poucos estudos relacionados ao SonoVue^®.

Objetivos

Avaliar a segurança do SonoVue^® durante o ecocardiograma sob estresse farmacológico (EEF) por meio da análise da incidência de reações alérgicas e da comparação entre os grupos quanto ao surgimento de arritmia, efeitos colaterais menores e eventos adversos.

Métodos

Estudo observacional, prospectivo, no qual 2.346 pacientes foram submetidos ao EEF e divididos em dois grupos: grupo 1 com ACE (n=1.099) e grupo 2 sem ACE (n=1.247). Os pacientes foram avaliados durante o EEF – 24 horas e 30 dias. Foi definido p significativo quando <0,05.

Resultados

O grupo 1 apresentou efeitos colaterais mais leves, como cefaleia (5/0,5% vs. 19/1,5%, p=0,012) e hipertensão reativa (3/0,3% vs . 19/1,5%, p=0,002), menos arritmias como extrassístoles ventriculares (180/16,4% vs . 247/19,8%, p=0,032) e taquicardia paroxística supraventricular (2/0,2% vs . 15/1,2%, p=0,003), assim como nenhum evento adverso como infarto agudo do miocárdio (IAM) e óbito. No grupo 2, um paciente apresentou IAM <24h (1/01%) e dois óbitos <30 dias (2/0,1%). Urticária relacionada ao SonoVue^® foi observada em 3 (0,3%) pacientes sem reação anafilática.

Conclusão

SonoVue^® demonstrou segurança durante o EEF, não sendo observados morte, IAM ou reação anafilática. Observou-se menor incidência de efeitos colaterais mais leves e arritmias no grupo que utilizou o ACE, assim como baixa incidência de reações alérgicas leves.

Effects of Copaiba Oil in Peripheral Markers of Oxidative Stress in a Model of Cor Pulmonale in Rats

Fundamento

Até o presente momento, os efeitos sistêmicos do óleo de copaíba jamais foram documentados no Cor pulmonale induzido por monocrotalina.

Objetivos

Investigar os efeitos do óleo de copaíba nos marcadores periféricos de stress oxidativo em ratos com Cor pulmonale.

Métodos

Ratos Wistar machos (170±20g, n=7/grupo) foram divididos em quatro grupos: controle (CO), monocrotalina (MCT), óleo de copaíba (O), e monocrotalina + óleo de copaíba (MCT-O). Foi administrada a MCT (60 mg/kg i.p.) e, depois de uma semana, foi iniciado o tratamento com óleo de copaíba (400 mg/kg/day-gavagem-14 dias). Foi realizado o ecocardiograma e, depois disso, foi coletado sangue do tronco para a realização de avaliações de stress oxidativo. Análise estatística: ANOVA de duas vias com teste Student-Newman-Keuls post hoc. P-valores <0,05 foram considerados significativos.

Resultados

O óleo de copaíba reduziu a resistência vascular pulmonar e a hipertrofia do ventrículo direito (VD) hipertrofia (Índice de Fulton (mg/mg)): MCT-O= 0,39±0,03; MCT= 0,49±0,01), e função sistólica melhorada (fração de encurtamento do VD, %) no grupo MCT-O (17,8±8,2) em comparação com o grupo de MCT (9,4±3,1; p<0,05). Além disso, no grupo MCT-O, espécies reativas do oxigênio e os níveis de carbonila foram reduzidos, e os parâmetros antioxidantes aumentaram no sangue periférico (p <0,05).

Conclusões

Os resultados deste estudo sugerem que o óleo de copaíba tem um efeito antioxidante sistêmico interessante, que se reflete na melhoria da função e na morfometria do VD nesse modelo de Cor pulmonale . A atenuação do Cor pulmonale promovida pelo óleo de copaíba coincidiu com uma redução no stress oxidativo sistêmico.

Updated knowledge and practical implementations of stress echocardiography in ischemic and non-ischemic cardiac diseases: an expert consensus of the Working Group of Echocardiography of the Hellenic Society of Cardiology

Stress echocardiography (SE) is a well-established and valid technique, widely-used for the diagnostic evaluation of patients with ischemic and non-ischemic cardiac diseases. This statement of the Echocardiography Working Group of the Hellenic Society of Cardiology summarizes the consensus of the writing group regarding the applications of SE, based on the expertise of their members and on a critical review of current medical literature. The main objectives of the consensus document include a comprehensive review of SE methodology and training, focusing on the preparation, the protocols used and the analysis of the SE images and an updated, evidence-based knowledge about SE applications on ischemic and non-ischemic heart diseases, such as in cardiomyopathies, heart failure and valvular heart disease.

Three Decades of Ultrasound Contrast Agents: A Review of the Past, Present and Future Improvements

Initial reports from the 1960s describing the observations of ultrasound contrast enhancement by tiny gaseous bubbles during echocardiographic examinations prompted the development of the first ultrasound contrast agent in the 1980s. Current commercial contrast agents for echography, such as Definity, Optison, Sonazoid and SonoVue, have proven to be successful in a variety of on- and off-label clinical indications. Whereas contrast-specific technology has seen dramatic progress after the introduction of the first approved agents in the 1990s, successful clinical translation of new developments has been limited during the same period, while understanding of microbubble physical, chemical and biologic behavior has improved substantially. It is expected that for a successful development of future opportunities, such as ultrasound molecular imaging and therapeutic applications using microbubbles, new creative developments in microbubble engineering and production dedicated to further optimizing microbubble performance are required, and that they cannot rely on bubble technology developed more than 3 decades ago.

Shock-Wave Therapy Improves Myocardial Blood Flow Reserve in Patients with Refractory Angina: Evaluation by Real-Time Myocardial Perfusion Echocardiography

BACKGROUND

Cardiac shock-wave therapy (CSWT) has been demonstrated as an option for the treatment of patients with refractory angina (RA), promoting immediate vasodilatory effects and, in the long-term, neoangiogenic effects that would be responsible for reducing the myocardial ischemic load. The aim of this study was to determine the effects of CSWT on myocardial blood flow reserve (MBFR) assessed by quantitative real-time myocardial perfusion echocardiography in patients with RA.

METHODS

Fifteen patients (mean age 61.5 ± 12.8 years) with RA who underwent CSWT during nine sessions, over 3 months of treatment, were prospectively studied. A total of 32 myocardial segments with ischemia were treated, while another 31 did not receive therapy because of technical limitations. Myocardial perfusion was evaluated at rest and after dipyridamole stress (0.84 mg/kg) before and 6 months after CSWT, using quantitative real-time myocardial perfusion echocardiography. Clinical effects were evaluated using Canadian Cardiovascular Society grading of angina and the Seattle Angina Questionnaire.

RESULTS

The ischemic segments treated with CSWT had increased MBFR (from 1.33 ± 0.22 to 1.74 ± 0.29, P < .001), a benefit that was not observed in untreated ischemic segments (1.51 ± 0.29 vs 1.54 ± 0.28, P = .47). Patients demonstrated increased global MBFR (from 1.78 ± 0.54 to 1.89 ± 0.49, P = .017). Semiquantitative single-photon emission computed tomographic analysis of the treated ischemic segments revealed a score reduction from 2.10 ± 0.87 to 1.68 ± 1.19 (P = .024). There was improvement in Canadian Cardiovascular Society score (from 3.20 ± 0.56 to 1.93 ± 0.70, P < .05) and in Seattle Angina Questionnaire score (from 42.3 ± 12.99 to 71.2 ± 14.29, P < .05). No major cardiovascular events were recorded during follow-up.

CONCLUSIONS

CSWT improved MBFR in ischemic segments, as demonstrated by quantitative real-time myocardial perfusion echocardiography. These results suggest that CSWT has the potential to increase myocardial blood flow, with an impact on symptoms and quality of life in patients with RA.

Stress echocardiography in coronary artery disease: a practical guideline from the British Society of Echocardiography

Stress echocardiography is an established technique for assessing coronary artery disease. It has primarily been used for the diagnosis and assessment of patients presenting with chest pain in whom there is an intermediate probability of coronary artery disease. In addition, it is used for risk stratification and to guide revascularisation in patients with known ischaemic heart disease. Although cardiac computed tomography has recently been recommended in the United Kingdom as the first-line investigation in patients presenting for the first time with atypical or typical angina, stress echocardiography continues to have an important role in the assessment of patients with lesions of uncertain functional significance and patients with known ischaemic heart disease who represent with chest pain. In this guideline from the British Society of Echocardiography, the indications and recommended protocols are outlined for the assessment of ischaemic heart disease by stress 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.

Utility and safety of three-dimensional contrast low-dose dobutamine echocardiography in the evaluation of myocardial viability early after an acute myocardial infarction

INTRODUCTION

The aim of the study was to determine the utility and safety of three-dimensional contrast low-dose dobutamine echocardiography (3DCLDDE) in the evaluation of myocardial viability early after ST-elevation myocardial infarction (STEMI).

MATERIAL AND METHODS

We prospectively evaluated a group of 100 consecutive patients. Myocardial viability was assessed using dobutamine echocardiography in 76 patients with segmental wall motion abnormalities, including 37 patients evaluated using 3DCLDDE and 39 patients evaluated using a standard low-dose dobutamine echocardiography protocol (LDDE), alternately.

RESULTS

Single ventricular ectopic beats were observed during the test in 1 (2.5%, 1, p = 1) patient in the 3DCLDDE group, while pain (1, p = 1) dyspnea (1, p = 1), single ventricular beats (2, p = 1), and complex ventricular arrhythmia (2, p = 0.49) were noted in 4 (10%) patients in the LDDE group. Five-year survival was 89% in the 3DCLDDE group and 87% in the LDDE group.

CONCLUSIONS

3DCLDDE and LDDE are equally safe and useful in patients after STEMI.

Predictive Value of Dobutamine Stress Perfusion Echocardiography in Contemporary End-Stage Liver Disease

BACKGROUND

The assessment of cardiac risk in contemporary liver transplantation (LT) has required more sensitive testing for the detection of occult coronary artery disease as well as microvascular and functional cardiac abnormalities. Because dobutamine stress perfusion echocardiography provides an assessment of both regional systolic and diastolic function as well as microvascular perfusion (MVP), we sought to examine its incremental value in this setting.

METHODS AND RESULTS

We evaluated the predictive value of dobutamine stress perfusion echocardiography in 296 adult patients with end-stage liver disease and preserved systolic function who underwent LT between 2008 and 2014. The primary outcome was cardiovascular death, nonfatal myocardial infarction, and/or sustained ventricular arrhythmias following LT. The main causes of liver failure were hepatitis C (25%) and nonalcoholic fatty liver disease (13%). Abnormal MVP during stress was observed in 18 patients (6%), whereas diastolic dysfunction was present in 109 patients (94 grade 1, 15 grade 2). Half of the patients (7 of 14) referred for angiography with abnormal MVP had significant epicardial disease by angiography, and these patients were revascularized prior to LT. Despite these interventions, the primary outcome still occurred in 9 patients (3%). Patients with abnormal MVP during dobutamine stress perfusion echocardiography had a 7-fold higher risk of a cardiovascular event following LT. Cox proportional hazards modeling examining clinical variables, left ventricular ejection fraction, diastolic function, and stress-induced wall motion abnormalities or MVP defects demonstrated that abnormal MVP was the only independent predictor of the primary outcome (P=0.004; hazard ratio 7.7).

CONCLUSIONS

Stress MVP assessments are highly predictive of cardiovascular outcome in current LT candidates.

Value of Low-Dose Dobutamine Stress Real-Time Myocardial Contrast Echocardiography in the Diagnosis of Coronary Heart Disease

To investigate the value of low-dose dobutamine stress real-time myocardial contrast echocardiography (RT-MCE) in the diagnosis of coronary heart disease (CHD). A total of 65 hospitalized patients with suspected or confirmed CHD were detected by RT-MCE combined with low-dose dobutamine stress (0.84 mg/kg). Perfusion curves were quantitatively analyzed using QLAB software. Peak intensity (A), slope of curves (β), and perfusion (A × β) were also calculated. Based on the results of coronary angiography, patients were divided into no obvious stenosis group (<50%), mild stenosis group (50%-74%), moderate stenosis group (75%-89%), and severe stenosis group (≥90%). The A, β, and A × β values before and after low-dose dobutamine stress of each group were compared. In the basal state and after low-dose dobutamine stress, the A, β, and A × β values significantly decreased as the stenosis degree of the myocardial segments increased. The same variation tendency was also found in the A, β, and A × β reserve values, and there was significant difference in these reserve values between moderate and severe stenosis groups and no obvious stenosis and mild stenosis groups. Collateral circulation had marked effects on the values of myocardial perfusion parameters and their reserve values, especially in the segments with severe stenosis. Low-dose dobutamine stress RT-MCE can be a sensitive method for clinical diagnosis and risk assessment of CHD and may provide a basis for further treatment of CHD.

Low Cost Magnetic Resonance Imaging-Compatible Stepper Exercise Device for Use in Cardiac Stress Tests

Cardiovascular disease is the leading cause of death worldwide. Many cardiovascular diseases are better diagnosed during a cardiac stress test. Current approaches include either exercise or pharmacological stress echocardiography and pharmacological stress magnetic resonance imaging (MRI). MRI is the most accurate noninvasive method of assessing cardiac function. Currently there are very few exercise devices that allow collection of cardiovascular MRI data during exercise. We developed a low-cost exercise device that utilizes adjustable weight resistance and is compatible with magnetic resonance (MR) imaging. It is equipped with electronics that measure power output. Our device allows subjects to exercise with a leg-stepping motion while their torso is in the MR imager. The device is easy to mount on the MRI table and can be adjusted for different body sizes. Pilot tests were conducted with 5 healthy subjects (3 male and 2 female, 29.2 ± 3.9 yr old) showing significant exercise-induced changes in heart rate (+42%), cardiac output (+40%) and mean pulmonary artery (PA) flow (+%49) post exercise. These data demonstrate that our MR compatible stepper exercise device successfully generated a hemodynamically stressed state while allowing for high quality imaging. The adjustable weight resistance allows exercise stress testing of subjects with variable exercise capacities. This low-cost device has the potential to be used in a variety of pathologies that require a cardiac stress test for diagnosis and assessment of disease progression.

An observational study of the occurrence of serious adverse reactions among patients who receive optison in routine medical practice

BACKGROUND

Reports of ultrasound contrast agent safety have been derived mainly from retrospective databases rather than from studies specifically designed to assess safety. The purpose of this study was to prospectively determine the safety of Optison (GE Healthcare, Princeton, NJ) in routine medical practice.

METHODS

Patients referred for routine rest or stress two-dimensional echocardiography who had indications for contrast were enrolled. Vital signs were obtained at baseline and at intervals up to 1 hour after dosing of Optison. Patients were followed for the development of any serious adverse event (SAE), defined as an event that causes death, is life threatening, requires or prolongs hospitalization, or causes another important event, for 24 hours after Optison administration.

RESULTS

A total of 1,039 patients were enrolled, and 76% had 24-hour follow-up. The median age was 60 years (range, 20-97 years), and 62% were men. The mean body mass index was 33 ± 9 kg/m(2). Patient comorbidities included hypertension (73%), hyperlipidemia (64%), smoking (52%), and diabetes (37%). There were significant increases in systolic blood pressure, heart rate, and respiratory rate between the baseline, 5- to 15-min, 30-min, and 60-min time points after the administration of Optison in patients undergoing stress studies but none in those undergoing rest studies. There was a total of six SAEs during the study, which were felt to be related not to Optison but rather to the stress test itself or to the patient's underlying pathology. Although two events were classified as SAEs because of hospitalization, the hospitalizations were appropriate for pathology that would have been missed without Optison use.

CONCLUSIONS

In this large, prospective safety study of Optison during routine resting and stress echocardiography, no SAEs related to Optison developed. Optison helped define abnormalities that required appropriate hospitalization for further management.

Stress echocardiography: safety and tolerability

Background

Stress echocardiography is a valuable tool for the noninvasive diagnosis of ischemic heart disease. Despite its widely use in the clinical practice, safety and side effects profile have never been evaluated in Moroccans.

The aim

To assess the safety and tolerability of the two stress echo modalities in Moroccans.

Methods

The study was made by 311 patients with known or suspected coronary artery disease, 203 underwent exercise echocardiography and 108 underwent dobutamine echocardiography, major and minor rhythmic complications and side effects were recorded for the two groups.

Results

We registered 3 (2, 8%) major rhythmic events in the dobutamine group (2 sustained supraventricular tachycardia and 1 sustained ventricular tachycardia), there was no major rhythmic events in the exercise group. Minor rhythmic events were frequent (43, 5% in the dobutamine group and 19, 2% in the exercise group with a p = 0, 0001). Severe hypotension occurs in 4 (3, 7%) patients during a dobutamine stress, there was no significant drop in the blood pressure during exercise stress procedures. Non cardiac side effects were more common among patients who underwent a dobutamine stress echo (13, 9% vs. 3, 4% with p = 0,001).

Conclusion

Exercise is safer than dobutamine stress echocardiography, complications and adverse effects with the use of dobutamine are usually minor and self-limiting.

Rapid Detection of Coronary Artery Stenoses With Real-Time Perfusion Echocardiography During Regadenoson Stress

Background—

Real-time myocardial contrast echocardiography permits the detection of myocardial perfusion abnormalities during stress echocardiography, which may improve the accuracy of the test in detecting coronary artery stenoses. We hypothesized that this technique could be used after a bolus injection of the selective A2A receptor agonist regadenoson to rapidly and safely detect coronary artery stenoses.

Methods and Results—

In 100 patients referred for quantitative coronary angiography, real-time myocardial contrast echocardiography was performed during a continuous intravenous infusion of 3% Definity at baseline and at 2-minute intervals for up to 6 minutes after a regadenoson bolus injection (400 μg). Myocardial perfusion was assessed by examination of myocardial contrast replenishment after brief high mechanical index impulses. A perfusion defect was defined as a delay (>2 seconds) in myocardial contrast replenishment in 2 contiguous segments. Wall motion was also analyzed. The overall sensitivity/specificity/accuracy for myocardial perfusion analysis in detecting a >50% diameter stenosis was 80%/74%/78%, whereas for wall motion analysis it was 60%/72%/66% ( P <0.001 for differences in sensitivity). Sensitivity for myocardial perfusion analysis was highest on images obtained during the first 2 minutes after regadenoson bolus ( P <0.001 compared with wall motion), whereas wall motion sensitivity was highest at the 4-to-6–minute period after the bolus. No significant side effects occurred after regadenoson bolus injection.

Conclusions—

Regadenoson real-time myocardial contrast echocardiography appears to be a feasible, safe, and rapid noninvasive method for the detection of significant coronary artery stenoses.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT0087369.

Myocardial ischaemia and viability: the pivotal role of echocardiography

Echocardiography has a central role for the diagnosis and management of patients with known or suspected coronary artery disease. Besides the fact that it provides an essential role in the differential diagnosis of patients presenting with chest pain in the emergency department, echocardiography provides a comprehensive non-invasive haemodynamic and functional assessment of those patients. Stress echocardiography in many institutions is now the preferred stress modality associated with imaging as it is cost-effective and does not use ionizing radiation. It is used for assessing patients with known or suspected coronary artery disease, risk stratification and for assessing myocardial viability. The recent introductions of ultrasound contrast agents as well as deformation imaging techniques have eliminated the last limitations of stress echocardiography such as image quality and quantification, respectively.

Contrast echocardiography in Australian clinical practice

BACKGROUND

The second-generation contrast agent Definity (a perflutren microsphere) became available in Australia in mid-2007. We describe the introduction of contrast echocardiography into a high-volume quaternary teaching hospital, performing over 16,000 echocardiograms per year. Workflow protocols were developed for patient selection, contrast administration, and image acquisition and analysis.

METHODS

Data were prospectively collected for all contrast cases. Endocardial definition scores were derived by three independent observers before and after contrast administration, and statistically compared.

RESULTS

161 patients received contrast in the first 12 months of the contrast program. There was statistically significant improvement in endocardial definition scores after contrast administration (p=0.0001), and reduction in inter-observer variability of wall motion assessment. A number of clinically significant findings (pseudoaneurysm, non-compaction, thrombus) were detected on contrast echo that were not apparent on standard 2D imaging. Adverse events were rare (0.6%) with no life-threatening events.

CONCLUSIONS

The introduction of a second-generation contrast agent into clinical workflow in a hospital echocardiography department resulted in a statistically significant improvement in endocardial definition, and safely provided diagnostic imaging in cases which were otherwise non-diagnostic. Inter-observer variability was reduced, and diagnostic yield increased. These results reflect previously published data, and indicate that contrast echocardiography is feasible in Australian clinical practice.

Meta-analysis of adverse cardiovascular events associated with echocardiographic contrast agents

In October 2007, the Federal Drug Agency issued a black box warning for contrast agents used in patients undergoing echocardiography and restricted their use in patients with acute coronary syndrome, a decompensated heart, and respiratory failure. We performed a systemic review and meta-analysis to study the adverse effects of contrast agents used with respect to myocardial infarction and all-cause mortality. MEDLINE, EMBASE, BIOSIS, and Cochrane databases from inception to October 2009 were searched for studies that reported myocardial infarction and all-cause mortality after the use of contrast agents for echocardiography. A total of 8 studies were included in the present meta-analysis. A random-effect model was used, and between-studies heterogeneity was estimated with I(2). A total of 8 studies reported death as an outcome and only 4 reported myocardial infarction. The incidence of death in the contrast group was 0.34% (726 of 211,162 patients) compared to 0.9% (45,970 of 5,078,666 patients) in the noncontrast group. The pooled odds ratio was 0.57 (95% confidence interval 0.32 to 1.01, p = 0.05). The reported incidence of myocardial infarction in the contrast group was 0.15% (86 of 57,264 patients) compared to 0.2% (92 of 44,503 patients) in the noncontrast group. The pooled odds ratio was 0.85 (95% confidence interval 0.35 to 2.05, p = 0.72). Significant heterogeneity was seen among the studies. In conclusion, the cumulative evidence has suggested that the use of contrast agents for echocardiography is safe and not associated with a greater incidence of myocardial infarction or and mortality.

Incremental value of contrast myocardial perfusion to detect intermediate versus severe coronary artery stenosis during stress-echocardiography

Background

We aimed to compare the incremental value of contrast myocardial perfusion imaging (MPI) for the detection of intermediate versus severe coronary artery stenosis during dipyridamole-atropine echocardiography (DASE).

Wall motion (WM) assessment during stress-echocardiography demonstrates suboptimal sensitivity to detect coronary artery disease (CAD), particularly in patients with isolated intermediate (50%-70%) coronary stenosis.

Methods

We performed DASE with MPI in 150 patients with a suspected chest pain syndrome who were given clinical indication to coronary angiography.

Results and discussion

When CAD was defined as the presence of a ≥50% stenosis, the addition of MPI increased sensitivity (+30%) and decreased specificity (-14%), with a final increase in total diagnostic accuracy (+16%, p < 0.001). The addition of MPI data substantially increased the sensitivity to detect patients with isolated intermediate stenosis from 37% to 98% (p < 0.001); the incremental sensitivity was much lower in patients with severe stenosis, from 85% to 96% (p < 0.05), at the expense of a higher decrease in specificity and a final decrease in total diagnostic accuracy (-18%, p < 0.001).

Conclusions

The addition of MPI on top of WM analysis during DASE increases the diagnostic sensitivity to detect obstructive CAD, whatever its definition (≥50% or > 70% stenosis), but it is mainly driven by the sensitivity increase in the intermediate group (50%-70% stenosis).

The total diagnostic accuracy increased only when defining CAD as ≥50% stenosis, since in patients with severe stenosis (> 70%) the decrease in specificity is not counterbalanced by the minor sensitivity increase.

Myocardial perfusion imaging with contrast ultrasound

This report reviews the development and clinical application of myocardial perfusion imaging with myocardial contrast echocardiography (MCE). This includes the development of microbubble formulations that permit the detection of left ventricular contrast from venous injection and the imaging techniques that have been invented to detect the transit of these microbubbles through the microcirculation. The methods used to quantify myocardial perfusion during a continuous infusion of microbubbles are described. A review of the clinical studies that have examined the clinical utility of myocardial perfusion imaging with MCE during rest and stress echocardiography is then presented. The limitations of MCE are also discussed.

Effects of exercise training on myocardial blood flow reserve in patients with heart failure and left ventricular systolic dysfunction

Exercise training has been shown to be effective in improving exercise capacity and quality of life in patients with heart failure and left ventricular (LV) systolic dysfunction. Real-time myocardial contrast echocardiography (RTMCE) is a new technique that allows quantitative analysis of myocardial blood flow (MBF). The aim of this study was to determine the effects of exercise training on MBF in patients with LV dysfunction. We studied 23 patients with LV dysfunction who underwent RTMCE and cardiopulmonary exercise testing at baseline and 4 months after medical treatment (control group, n = 10) or medical treatment plus exercise training (trained group, n = 13). Replenishment velocity (beta) and MBF reserves were derived from quantitative RTMCE. The 4-month exercise training consisted of 3 60-minute exercise sessions/week at an intensity corresponding to anaerobic threshold, 10% below the respiratory compensation point. Aerobic exercise training did not change LV diameters, volumes, or ejection fraction. At baseline, no difference was observed in MBF reserve between the control and trained groups (1.89, 1.67 to 1.98, vs 1.81, 1.28 to 2.38, p = 0.38). Four-month exercise training resulted in a significant increase in beta reserve from 1.72 (1.45 to 1.48) to 2.20 (1.69 to 2.77, p <0.001) and an MBF reserve from 1.81 (1.28 to 2.38) to 3.05 (2.07 to 3.93, p <0.001). In the control group, beta reserve decreased from 1.51 (1.10 to 1.85) to 1.46 (1.14 to 2.33, p = 0.03) and MBF reserve from 1.89 (1.67 to 1.98) to 1.55 (1.11 to 2.27, p <0.001). Peak oxygen consumption increased by 13.8% after 4 months of exercise training and decreased by 1.9% in the control group. In conclusion, exercise training resulted in significant improvement of MBF reserve in patients with heart failure and LV dysfunction.

(31)P cardiac magnetic resonance spectroscopy during leg exercise at 3 Tesla

Investigation of phosphorus ((31)P) magnetic resonance spectroscopy under stress conditions provides a non-invasive tool to examine alterations in cardiac high-energy phosphate metabolism that may not be evident at rest. Our aim was to establish cardiac (31)P MR spectroscopy during leg exercise at 3T. The increased field strength should provide a higher signal to noise ratio than at lower field strengths. Furthermore, relatively high temporal resolution at a sufficiently fine spatial resolution should be feasible. (31)P MR spectra were obtained with a 3D acquisition weighted chemical shift imaging sequence in 20 healthy volunteers at rest, during dynamic physiological leg exercise and after recovery at 3T. Haemodynamic measurements were made throughout and the rate pressure product calculated. With exercise, the mean heart rate increased by 73%, achieving a mean increase in rate pressure product of 115%. The corrected PCr/ATP ratio for subjects at rest was 2.02 +/- 0.43, exercise 2.14 +/- 0.67 (P = 0.54 vs. rest) and at recovery 2.03 +/- 0.52 (P = 0.91 vs. rest, P = 0.62 vs. exercise). A cardiac (31)P MR spectroscopy physiological exercise-recovery protocol is feasible at 3T. There was no significant change in high-energy cardiac phosphate metabolite concentrations in healthy volunteers at rest, during physiological leg exercise or during recovery. When applied to patients with heart disease, this protocol should provide insights into physiological and pathological cardiac metabolism.

Safety of contrast in stress echocardiography in stable patients and in patients with suspected acute coronary syndrome but negative 12-hour troponin

Limited studies are available demonstrating the safety of contrast agents in patients undergoing stress echocardiography and none in patients with suspected acute coronary syndrome (ACS). Therefore, we sought to assess the safety profile of contrast agents in patients with stable chest pain and in those with suspected ACS (nondiagnostic electrocardiogram and negative initial 12-hour cardiac troponin test results). During a 4-year period, 3,704 patients underwent stress echocardiography (exercise or dobutamine), of whom, 929 (25%) had suspected ACS. Contrast agents (SonoVue 46%, Luminity 54%) were used in 1,150 patients (31%). No patients died with or without contrast administration. No nonfatal acute myocardial infarction occurred in patients administered contrast agents compared with 3 cases of acute myocardial infarction in the noncontrast group (p = 0.24). Two cases of sustained ventricular tachycardia developed, one in each group (p = 0.98). Compared with those who did not receive contrast, patients in both the stable chest pain and the suspected ACS groups had a greater burden of cardiovascular risk factors. The left ventricular function at rest was significantly worse in the patients who received contrast than in those who did not in the suspected ACS group. Also, a greater ischemic burden was present in those receiving contrast than in those not receiving it in both the stable chest pain and the suspected ACS groups. In conclusion, despite the presence of greater risk features compared with patients undergoing unenhanced stress echocardiography, the administration of ultrasound contrast agents (SonoVue and Luminity) in those with stable chest pain and those with suspected ACS was not associated with excess adverse events.

Dobutamine stress testing as a diagnostic tool for evaluation of myocardial contractile reserve in asymptomatic or mildly symptomatic patients with dilated cardiomyopathy

OBJECTIVES

We performed dobutamine stress testing for evaluation of myocardial contractile reserve in asymptomatic or mildly symptomatic patients with dilated cardiomyopathy (DCM).

BACKGROUND

Catecholamine sensitivity is reduced in failing hearts as a result of myocardial abnormalities in the beta-adrenergic receptor signaling pathway. However, little is known about adrenergic myocardial contractile reserve in asymptomatic or mildly symptomatic patients with DCM.

METHODS

The maximal first derivative of left ventricular pressure (LV dP/dt(max)) was determined during infusion of dobutamine (10 microg kg(-1) min(-1)) in 46 asymptomatic or mildly symptomatic (New York Heart Association functional class I or II) patients with DCM. The expression of messenger ribonucleic acid (mRNA) for contractile regulatory proteins in endomyocardial biopsy specimens was quantified by reverse transcription and real-time polymerase chain reaction analysis. Plasma norepinephrine levels were measured in all patients and [(123)I]metaiodobenzylguanidine (MIBG) scintigraphy performed.

RESULTS

Patients were classified into 3 groups based on the percentage increase in LV dP/dt(max) induced by dobutamine (DeltaLV dP/dt(max)) and on LV ejection fraction (LVEF) at baseline: group I (n = 18): DeltaLV dP/dt(max) >100% and LVEF >25%; group IIa (n = 17): DeltaLV dP/dt(max) <or=100% and LVEF > 25%; and group IIb (n = 11): DeltaLV dP/dt(max) <or=100% and LVEF <or=25%. The amounts of beta(1)-adrenergic receptor, sarcoplasmic reticulum Ca(2+)-adenosine triphosphatase, and phospholamban mRNA were significantly smaller in groups IIa and IIb than in group I. The plasma norepinephrine level was increased and the delayed heart/mediastinum count ratio in MIBG scintigraphy was decreased in both groups IIa and IIb.

CONCLUSIONS

Dobutamine stress testing is a useful diagnostic tool for identifying reduced adrenergic myocardial contractile reserve related to altered myocardial expression of beta(1)-adrenergic receptor, sarcoplasmic reticulum Ca(2+)-adenosine triphosphatase, and phospholamban genes even in asymptomatic or mildly symptomatic patients with DCM.

Contrast echocardiography: an update

Despite the advent of tissue harmonic imaging, echocardiography fails to produce diagnostically useful images in a significant proportion of patients. This often leads to inaccurate assessment of left ventricular function, necessitating the use of other, more expensive and laborious imaging techniques, purely for diagnostic purposes. This has facilitated the development of microbubbles, which together with ultrasound, produce opacification of the left ventricular cavity, thus enabling clear visualization and accurate quantification of left ventricular function. Contrast agents have also facilitated the development of myocardial contrast echocardiography. This allows assessment of cardiac anatomy, function, and perfusion, all in one sitting, by the bedside. Contrast ultrasound imaging also has now been applied to newer techniques (eg, real-time three-dimensional echocardiography) and is also showing promise in other cardiovascular scans (eg, carotid ultrasound for intima-media thickness). Thus, contrast agents play a pivotal role in noninvasive cardiovascular imaging and its use worldwide is likely to increase.

American Society of Echocardiography Consensus Statement on the Clinical Applications of Ultrasonic Contrast Agents in Echocardiography

ACCREDITATION STATEMENT: The American Society of Echocardiography (ASE) is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The ASE designates this educational activity for a maximum of 1 AMA PRA Category 1 Credit.trade mark Physicians should only claim credit commensurate with the extent of their participation in the activity. The American Registry of Diagnostic Medical Sonographers and Cardiovascular Credentialing International recognize the ASE's certificates and have agreed to honor the credit hours toward their registry requirements for sonographers. The ASE is committed to resolving all conflict-of-interest issues, and its mandate is to retain only those speakers with financial interests that can be reconciled with the goals and educational integrity of the educational program. Disclosure of faculty and commercial support sponsor relationships, if any, have been indicated.

TARGET AUDIENCE

This activity is designed for all cardiovascular physicians, cardiac sonographers, and nurses with a primary interest and knowledge base in the field of echocardiography; in addition, residents, researchers, clinicians, sonographers, and other medical professionals having a specific interest in contrast echocardiography may be included.

OBJECTIVES

Upon completing this activity, participants will be able to: 1. Demonstrate an increased knowledge of the applications for contrast echocardiography and their impact on cardiac diagnosis. 2. Differentiate the available ultrasound contrast agents and ultrasound equipment imaging features to optimize their use. 3. Recognize the indications, benefits, and safety of ultrasound contrast agents, acknowledging the recent labeling changes by the US Food and Drug Administration (FDA) regarding contrast agent use and safety information. 4. Identify specific patient populations that represent potential candidates for the use of contrast agents, to enable cost-effective clinical diagnosis. 5. Incorporate effective teamwork strategies for the implementation of contrast agents in the echocardiography laboratory and establish guidelines for contrast use. 6. Use contrast enhancement for endocardial border delineation and left ventricular opacification in rest and stress echocardiography and unique patient care environments in which echocardiographic image acquisition is frequently challenging, including intensive care units (ICUs) and emergency departments. 7. Effectively use contrast echocardiography for the diagnosis of intracardiac and extracardiac abnormalities, including the identification of complications of acute myocardial infarction. 8. Assess the common pitfalls in contrast imaging and use stepwise, guideline-based contrast equipment setup and contrast agent administration techniques to optimize image acquisition.

Safety of contrast administration for endocardial enhancement during stress echocardiography compared with noncontrast stress

The aim was to evaluate the safety of stress echocardiography using contrast (CE) for endocardial enhancement compared with a noncontrast (NCE) cohort in a large nonselect population. The recent Food and Drug Administration warning cited lack of data for safety regarding the use of contrast in conjunction with stress echocardiography. A detailed record review was performed for 5,069 consecutive patients who underwent stress echocardiography (58% pharmacologic, 42% exercise) during an 8-year period. Contrast use, hemodynamics, and adverse clinical and electrocardiographic events were evaluated until time of discharge from the laboratory. Contrast was administered to 2,914 patients (58%) and was higher in in-patients (66%) and during dobutamine stress (67%). Compared with the NCE group, the CE group was older (median age 61 vs 58 years) and had more depressed left ventricular ejection fraction <50% (14% vs 11%; all p <0.001). The CE group experienced more chest pain (11% vs 8%; p = 0.001), back pain (0.6% vs 0.05%; p <0.001), and premature ventricular contractions (odds ratio 1.42, 95% confidence interval 1.19 to 1.69, p <0.001). There was no sustained ventricular tachycardia, ventricular fibrillation, cardiac arrest, or death in either group. One uncomplicated acute myocardial infarction and 1 anaphylactoid reaction occurred in the CE group, and none occurred in the NCE group (p = 0.51). Rates of clinically significant arrhythmias were similar in both groups (CE 2.1% vs NCE 1.9%; p = 0.8). In conclusion, although CE of echocardiographic images was used more often in patients with a higher cardiac risk profile, the risk of major adverse events was very small in both the CE and NCE stress echocardiography cohorts.

New Echocardiographic Techniques for Evaluating Left Ventricular Myocardial Function

Ultrasound imaging of the heart continues to play an important role in diagnosis and management of patients with cardiovascular diseases. Recent advances in ultrasound technology and introduction of newer imaging modalities have enabled improved assessment of left ventricular myocardial function. Tissue Doppler imaging and 2-dimensional speckle tracking allow more objective quantification of myocardial function in the form of tissue velocities, displacement, strain, and strain rate. Similarly, contrast-enhanced echocardiography and 3-dimensional echocardiography have provided a unique insight into left ventricular form and function that was not possible by unenhanced 2-dimensional echocardiography. In this review, the authors discuss the clinical application of these new imaging techniques in the assessment of left ventricular myocardial function.

Prognostic value of dobutamine stress echocardiography with early injection of atropine with versus without chronic beta-blocker therapy in patients with known or suspected coronary heart disease

Although a new protocol of dobutamine stress echocardiography with the early injection of atropine (EA-DSE) has been demonstrated to be useful in reducing adverse effects and increasing the number of effective tests and to have similar accuracy for detecting coronary artery disease (CAD) compared with conventional protocols, no data exist regarding its ability to predict long-term events. The aim of this study was to determine the prognostic value of EA-DSE and the effects of the long-term use of beta blockers on it. A retrospective evaluation of 844 patients who underwent EA-DSE for known or suspected CAD was performed; 309 (37%) were receiving beta blockers. During a median follow-up period of 24 months, 102 events (12%) occurred. On univariate analysis, predictors of events were the ejection fraction (p <0.001), male gender (p <0.001), previous myocardial infarction (p <0.001), angiotensin-converting enzyme inhibitor therapy (p = 0.021), calcium channel blocker therapy (p = 0.034), and abnormal results on EA-DSE (p <0.001). On multivariate analysis, the independent predictors of events were male gender (relative risk [RR] 1.78, 95% confidence interval [CI] 1.13 to 2.81, p = 0.013) and abnormal results on EA-DSE (RR 4.45, 95% CI 2.84 to 7.01, p <0.0001). Normal results on EA-DSE with beta blockers were associated with a nonsignificant higher incidence of events than normal results on EA-DSE without beta blockers (RR 1.29, 95% CI 0.58 to 2.87, p = 0.54). Abnormal results on EA-DSE with beta blockers had an RR of 4.97 (95% CI 2.79 to 8.87, p <0.001) compared with normal results, while abnormal results on EA-DSE without beta blockers had an RR of 5.96 (95% CI 3.41 to 10.44, p <0.001) for events, with no difference between groups (p = 0.36). In conclusion, the detection of fixed or inducible wall motion abnormalities during EA-DSE was an independent predictor of long-term events in patients with known or suspected CAD. The prognostic value of EA-DSE was not affected by the long-term use of beta blockers.

Dobutamine stress MRI versus threedimensional contrast echocardiography: It's all Black and White

Dobutamine stress magnetic resonance imaging is considered the superior stress modality to detect wall motion abnormalities. In this report we demonstrate the strengths of a newly developed stress modality: dobutamine stress contrastenhanced real-time three-dimensional echocardiography. This stress modality may become a competitor of stress magnetic resonance imaging allowing fast acquisition and an unlimited number of left ventricular cross sections. Unfortunately, at the moment adequate imaging with stress realtime three-dimensional echocardiography is only possible in a minority of cardiac patients. (Neth Heart J 2008;16:217-8.).

The acute effect of an echo-contrast agent on right ventricular dimensions and contractility in pigs

BACKGROUND

: The aim of the present study was to examine the effect of the second-generation ultrasound contrast agent (2nd GUCA) SonoVue on right ventricular (RV) dimensions and contractility and to investigate whether a dose-related interaction exists between the contrast agent and RV function.

METHODS

: Twenty-eight pigs were randomly assigned to 3 groups for intravenous administration: a low-dose group (0.5 cc of SonoVue), a high-dose group (1 cc of SonoVue), and a control group (2 cc of normal saline). RV end-diastolic (EDD) and end-systolic dimension (ESD) and pulmonary pressure (PP) were measured, and the fractional shortening (FS%) was calculated before the administration of SonoVue or normal saline and after the return of the RV-EDD or PP to the baseline value. The time to reach maximal RV-EDD or PP value and the time until the return of RV-EDD or PP to the baseline value were also measured.

RESULTS

: Contrast agent infusion was followed by an acute transient increase of RV-EDD, RV-ESD, FS, and PP in both the low-dose and high-dose groups, but the increase was greater in the high-dose group. FS and PP did not change significantly in the control group. A dose-dependent delay in the time from baseline to maximum RV-EDD and PP was detected in the high-dose group (P < 0.001 for both) as well as a delay in the return from maximum to the baseline values (P < 0.001 for both).

CONCLUSIONS

: Administration of the 2nd GUCA SonoVue is associated with an acute, transient, dose-dependent RV dilatation and an increase in pulmonary pressure with a consequent impact on RV contractility.

Contrast echocardiography: evidence for clinical use

The failure of echocardiography to give diagnostically useful information in a significant proportion of patients has led to the development of specific contrast agents to enhance imaging. Suitable contrast media must have the ability to modify ultrasound characteristics, be capable of crossing the pulmonary capillary bed, show stability over the duration of a procedure, offer low blood solubility with low toxicity and be rapidly eliminated. The current generation of ultrasound contrast agents comprises microbubbles of a high molecular-weight gas encapsulated in a shell of phospholipid or protein. A review of the clinical evidence shows that these agents are clinically effective in enhancing echocardiographic imaging. They enable the rescue of failed procedures, often sparing patients from invasive tests, but appear not to add to the burden of side effects. Indeed, the benefits of using contrast agents in stress echocardiography have been recommended in recently published American Society of Echocardiography guidelines. Myocardial contrast echocardiography has now developed to the stage where assessment of myocardial perfusion for the detection of coronary artery disease is possible with the same diagnostic accuracy as radionuclide imaging. However, in comparison with the latter technique, it is less expensive, is more portable, and avoids the use of ionizing radiation. It is precisely the ability of myocardial contrast echocardiography to simultaneously assess function and perfusion at the bedside that has given it a unique role in clinical practice. This review provides an overview of the clinical evidence supporting the efficacy of contrast echocardiography in the assessment of myocardial structure, function, and perfusion.