Value of vasodilator stress myocardial contrast echocardiography and magnetic resonance imaging for the differential diagnosis of ischemic versus nonischemic cardiomyopathy

Data on diagnostic performance of stress perfusion cardiac magnetic resonance for coronary artery disease detection at the vessel level

Stress perfusion cardiac magnetic resonance (CMR) has been proposed as an important gatekeeper for invasive coronary angiography (ICA) and percutaneous coronary interventions (PCI) in patients evaluated for possible coronary artery disease (CAD) (Fihn et al., 2012; Montalescot et al., 2013) [1], [2]. Several meta-analyses have evaluated the accuracy of stress perfusion CMR to diagnose CAD at the vessel level (Danad et al., 2017; Dai et al., 2016; Jiang et al., 2016; Takx et al., 2015; Li et al., 2015; Desai and Jha, 2013; Jaarsma et al. 2012; Hamon et al., 2010; Nandalur et al. 2007) [3], [4], [5], [6], [7], [8], [9], [10], [11]. However, they included in the same analysis studies with different definitions of significant CAD (i.e. fractional flow reserve [FFR] < 0.75 and < 0.80 or coronary stenosis ≥ 50% and ≥ 70%), magnetic field strength (1.5 or 3 Tesla [T]), and study protocol (integration or not of late gadolinium enhancement [LGE] into stress perfusion protocol). Data of 34 studies (6091 arteries) have been pooled with the aim of analyzing the accuracy of stress perfusion CMR for the diagnosis of ischemic heart disease at the vessel level according to different definitions of significant CAD, magnetic field strength and study protocol (Arnold et al., 2010; Bettencourt et al., 2013; Cheng et al., 2007; Chiribiri et al., 2013; Cury et al., 2006; De Mello et al., 2012; Donati et al., 2010; Ebersberger et al., 2013; Gebker et al., 2008; Greulich et al., 2015; Hussain et al., 2016; Ishida et al., 2005, 2003; Kamiya et al., 2014; Kitagawa et al., 2008; Klein et al., 2008; Klem et al., 2006; Klumpp et al., 2010; Krittayaphong et al., 2009; Lockie et al., 2011; Ma et al., 2012; Merkle et al., 2007; Meyer et al., 2008; Mor-Avi et al., 2008; Pan et al., 2015; Papanastasiou et al., 2016; Pons Lladó et al., 2004; Sakuma et al., 2005; Salerno et al., 2014; Scheffel et al., 2010; van Werkhoven et al., 2010; Walcher et al., 2013; Watkins et al., 2009; Yun et al., 2015) [12–45]. This article describes data related article titled “Diagnostic Performance of Stress Perfusion Cardiac Magnetic Resonance for the Detection of Coronary Artery Disease” (Kiaos et al., submitted for publication) [46].

Comparison of treadmill exercise stress cardiac MRI to stress echocardiography in healthy volunteers for adequacy of left ventricular endocardial wall visualization: A pilot study

PURPOSE

To compare exercise stress cardiac magnetic resonance (cardiac MR) to echocardiography in healthy volunteers with respect to adequacy of endocardial visualization and confidence of stress study interpretation.

MATERIALS AND METHODS

Twenty-eight healthy volunteers (age 28 ± 11 years, 15 males) underwent exercise stress echo and cardiac MR one week apart assigned randomly to one test first. Stress cardiac MR was performed using an MRI-compatible treadmill; stress echo was performed as per routine protocol. Cardiac MR and echo images were independently reviewed and scored for adequacy of endocardial visualization and confidence in interpretation of the stress study.

RESULTS

Heart rate at the time of imaging was similar between the studies. Average time from cessation of exercise to start of imaging (21 vs. 31 s, P < 0.001) and time to acquire stress images (20 vs. 51 s, P < 0.001) was shorter for cardiac MR. The number of myocardial segments adequately visualized was significantly higher by cardiac MR at rest (99.8% vs. 96.4%, P = 0.002) and stress (99.8% vs. 94.1%, P = 0.001). The proportion of subjects in whom there was high confidence in the interpretation was higher for cardiac MR than echo (96% vs. 60%, P = 0.005).

CONCLUSION

Exercise stress cardiac MR to assess peak exercise wall motion is feasible and can be performed at least as rapidly as stress echo.

Clinical usefulness of low-dose dobutamine stress real-time myocardial contrast echocardiography for detection of viable myocardium

OBJECTIVES

To evaluate and compare the diagnostic accuracy of semi-quantitative and quantitative real-time myocardial contrast echocardiography (RT-MCE) with low-dose dobutamine stress echocardiography (LD-DSE) in detecting viable myocardium.

METHODS

Thirty in-patients with coronary artery disease and regional wall motion abnormalities underwent RT-MCE without and with LD-DSE. Percutaneous coronary intervention was performed within 1 week after RT-MCE in all patients. Myocardial perfusion was evaluated from A, β, and A × β indices from microbubble replenishment curves. The motion of each myocardium segment was observed by routine echocardiography 1, 3, and 6 months after percutaneous coronary intervention and its improvement over time was the criterion of viable myocardium.

RESULTS

RT-MCE sensitivity and specificity for the assessment of viable myocardium were 71.7% and 69.8%, rising to 81.3% and 76.7% (p < 0.05) when combined with LD-DSE. Using quantitative RT-MCE with cutoff values of A, β, and A × β, the sensitivity and specificity were 75.6%, 78.8%, 82.1%, and 82.4%, 77.9%, 78.6%, respectively. When combined with LD-DSE, the sensitivity and specificity were 86.0%, 83.2%; 88.9% and 84.1%; 89.6%, 79.9%, respectively.

CONCLUSIONS

Quantitative RT-MCE analysis yielded higher sensitivity and specificity than semi-quantitative RT-MCE with or without LD-DSE for the detection of viable myocardium.

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.

Prognostic value of dipyridamole stress myocardial contrast echocardiography: comparison with single photon emission computed tomography

BACKGROUND

Dipyridamole stress myocardial contrast echocardiography (MCE) can be used to detect coronary artery disease (CAD). Because it measures myocardial blood flow velocity in addition to measuring myocardial blood volume, it was hypothesized that it should have greater prognostic utility than single photon-emission computed tomography (SPECT), which measures only myocardial blood volume. Because blood flow mismatch precedes wall thickening (WT) abnormalities during demand ischemia, it was also postulated that perfusion on MCE would be superior to WT abnormalities on echocardiography for this purpose.

METHODS

The incidence of nonfatal myocardial infarction and cardiac death was determined in 261 patients with known or suspected CAD over a mean follow-up period of 14 months who underwent simultaneous dipyridamole stress MCE and 99mTc-sestamibi SPECT. Comparisons of survival curves were conducted with stratified (and unstratified) log-rank tests.

RESULTS

Abnormal results on MCE were found to be the best predictor of an adverse outcome (odds ratio, 23; 95% confidence interval, 6-201; P<.0001) and provided incremental prognostic value over clinical variables (age>60 years, the presence of >or=3 cardiac risk factors, known peripheral vascular disease, prior myocardial infarction, and left ventricular systolic function), inducible WT abnormalities, and SPECT. Prognoses were worst in patients who had both abnormal results on MCE and inducible WT abnormalities and best in those who had neither. Patients with abnormal results on MCE but no inducible WT abnormalities had intermediate outcomes.

CONCLUSION

In patients with known or suspected CAD undergoing dipyridamole stress, MCE provides powerful prognostic information that is superior to clinical variables, electrocardiography, left ventricular systolic function, WT analysis, and SPECT. MCE may therefore serve as a method of choice for myocardial perfusion assessment in patients with known or suspected CAD. Larger studies are needed to confirm these findings.

[Update on cardiac imaging techniques: echocardiography, cardiac magnetic resonance, and multidetector computed tomography]

This article contains a review of the most important publications on cardiac imaging that have appeared during 2008. During the year, we assisted with the clinical implementation of three-dimensional real-time transesophageal echocardiography, with the use of echocardiography for selecting patients for and monitoring those who underwent percutaneous aortic valve replacement (the majority of centers performing the technique were still in the learning phase), and with the emergence in the clinic of techniques for studying myocardial deformation. Also reviewed are the most significant developments in the application of echocardiography to coronary heart disease and cardiac resynchronization therapy and in 2 other techniques whose use is constantly increasing: cardiac magnetic resonance and multidetector cardiac computed tomography. The review ends with a description of the current state of the art in contrast echocardiography, with particular emphasis on safety in the context of recommendations made by the US Food and Drug Administration at the end of 2007.

Noninvasive techniques to assess myocardial ischemia in hypertensive patients

Hypertensive patients are more affected by coronary artery disease (CAD) than normotensive patients. Currently, established techniques are able to diagnose myocardial ischemia/CAD in hypertensive patients with suspected CAD. An irrevocable role remains for exercise electrocardiogram (ECG) owing to the many parameters evaluated under physiologic conditions. However, the suboptimal specificity of a positive exercise ECG demands further examination of hypertensive patients with either myocardial single-photon emission computed tomography (SPECT) or stress echocardiography, both more specific than exercise ECG in diagnosing CAD. The high specificity of imaging techniques also makes them highly predictive of cardiac events. Additional techniques to help diagnose CAD are available. Tissue Doppler imaging, strain and other echo-derived techniques may add quantitative elements to recognize CAD in hypertensive hearts. The accuracy of MRI is improving to study myocardial function and perfusion. Positron emission tomography and multislice computed tomography, also in-built with fusion scanners, are playing roles in combining coronary angiography and myocardial function/ischemia assessment. However, no significant application of these additional techniques is available for hypertensive patients. Epicardial CAD assessed by coronary angiography remains the gold standard to decide for revascularization procedures. The presence of microcirculatory dysfunction, a symptom typical of hypertensive hearts, is opening up new areas of noninvasive diagnostic techniques for the detection of coronary flow reserve (CFR) and related myocardial ischemia. The quantification of CFR may render this parameter pivotal to deciding the need for revascularization procedures of intermediate coronary stenosis and it may become an additional gold standard in evaluating coronary vessels. Moreover, even with normal epicardial coronary arteries, microcirculation dysfunction bears prognostic stratification capabilities for hypertensive patients and it may become a promising therapeutic target in the near future.