Prognostic significance of delayed-enhancement magnetic resonance imaging: survival of 857 patients with and without left ventricular dysfunction

Assessment of myocardial ischemia with cardiovascular magnetic resonance

Assessment of myocardial ischemia in symptomatic patients remains a common and challenging clinical situation faced by physicians. Risk stratification by presence of ischemia provides important utility for both prognostic assessment and management. Unfortunately, current noninvasive modalities possess numerous limitations and have limited prognostic capacity. More recently, ischemia assessment by cardiovascular magnetic resonance (CMR) has been shown to be a safe, available, and potentially cost-effective alternative with both high diagnostic and prognostic accuracy. Cardiovascular magnetic resonance has numerous advantages over other noninvasive methods, including high temporal and spatial resolution, relatively few contraindications, and absence of ionizing radiation. Furthermore, studies assessing the clinical utility and cost effectiveness of CMR in the short-term setting for patients without evidence of an acute myocardial infarction have also demonstrated favorable results. This review will cover techniques of ischemia assessment with CMR by both stress-induced wall motion abnormalities as well as myocardial perfusion imaging. The diagnostic and prognostic performance studies will also be reviewed, and the use of CMR for ischemia assessment will be compared with other commonly used noninvasive modalities.

Midwall fibrosis is an independent predictor of mortality in patients with aortic stenosis

OBJECTIVES

The goal of this study was to assess the prognostic significance of midwall and infarct patterns of late gadolinium enhancement (LGE) in aortic stenosis.

BACKGROUND

Myocardial fibrosis occurs in aortic stenosis as part of the hypertrophic response. It can be detected by LGE, which is associated with an adverse prognosis in a range of other cardiac conditions.

METHODS

Between January 2003 and October 2008, consecutive patients with moderate or severe aortic stenosis undergoing cardiovascular magnetic resonance with administration of gadolinium contrast were enrolled into a registry. Patients were categorized into absent, midwall, or infarct patterns of LGE by blinded independent observers. Patient follow-up was completed using patient questionnaires, source record data, and the National Strategic Tracing Service.

RESULTS

A total of 143 patients (age 68 ± 14 years; 97 male) were followed up for 2.0 ± 1.4 years. Seventy-two underwent aortic valve replacement, and 27 died (24 cardiac, 3 sudden cardiac deaths). Compared with those with no LGE (n = 49), univariate analysis revealed that patients with midwall fibrosis (n = 54) had an 8-fold increase in all-cause mortality despite similar aortic stenosis severity and coronary artery disease burden. Patients with an infarct pattern (n = 40) had a 6-fold increase. Midwall fibrosis (hazard ratio: 5.35; 95% confidence interval: 1.16 to 24.56; p = 0.03) and ejection fraction (hazard ratio: 0.96; 95% confidence interval: 0.94 to 0.99; p = 0.01) were independent predictors of all-cause mortality by multivariate analysis.

CONCLUSIONS

Midwall fibrosis was an independent predictor of mortality in patients with moderate and severe aortic stenosis. It has incremental prognostic value to ejection fraction and may provide a useful method of risk stratification.

The role of cardiac magnetic resonance in the evaluation of patients presenting with suspected or confirmed acute coronary syndrome

Cardiac magnetic resonance imaging (CMR) has an important emerging role in the evaluation and management of patients who present with symptoms concerning for acute coronary syndrome (ACS). This paper discusses the role of CMR in the emergency department setting, where CMR can aid in the early and accurate diagnosis of non-ST elevation ACS in low and intermediate risk patients. For those with confirmed myocardial infarction (MI), CMR provides comprehensive prognostic information and can readily diagnose structural complications related to MI. Furthermore, the pattern of late gadolinium enhancement (LGE) seen on CMR can help determine the etiology of cardiac injury in the subset of patients presenting with ACS who do not have obstructive coronary artery disease by angiography.

Quantitative assessment of artifacts on cardiac magnetic resonance imaging of patients with pacemakers and implantable cardioverter-defibrillators

BACKGROUND

The safety and clinical utility of MRI at 1.5 T in patients with cardiac implantable devices such as pacemakers (PM) and implantable cardioverter-defibrillators (ICD) have been reported. This study aims to evaluate the extent of artifacts on cardiac magnetic resonance (CMR) in patients with PM and ICD (PM/ICD).

METHODS AND RESULTS

A total of 71 CMR studies were performed with an established safety protocol in patients with prepectoral PM/ICD. The artifact area around the PM/ICD generator was measured in all short-axis (SA), horizontal (HLA), and vertical long-axis (VLA) SSFP cine planes. The location and extent of artifacts were also assessed in all SA (20 sectors per plane), HLA, and VLA (6 sectors per plane) late gadolinium-enhanced CMR (LGE-CMR) planes. The artifact area on cine CMR was significantly larger with ICD versus PM generators in each plane (P<0.001, respectively). In patients with left-sided ICD or biventricular ICD systems, the percentages of sectors with any artifacts on LGE-CMR were 53.7%, 48.0%, and 49.2% in SA, HLA, and VLA planes, respectively. Patients with left-sided PM or right-sided PM/ICD had fewer artifacts. Anterior and apical regions were severely affected by artifact caused by left-sided PM/ICD generators.

CONCLUSIONS

In contrast to patients with right-sided PM/ICD and left-sided PM, the anterior and apical left ventricle can be affected by susceptibility artifacts in patients with left-sided ICD. Artifact reduction methodologies will be necessary to improve the performance of CMR in patients with left sided ICD systems.

The role of dobutamine stress cardiovascular magnetic resonance in the clinical management of patients with suspected and known coronary artery disease

BACKGROUND

Recent studies have demonstrated the consistently high diagnostic and prognostic value of dobutamine stress cardiovascular magnetic resonance (DCMR). The value of DCMR for clinical decision making still needs to be defined. Hence, the purpose of this study was to assess the utility of DCMR regarding clinical management of patients with suspected and known coronary artery disease (CAD) in a routine setting.

METHODS AND RESULTS

We prospectively performed a standard DCMR examination in 1532 consecutive patients with suspected and known CAD. Patients were stratified according to the results of DCMR: DCMR-positive patients were recommended to undergo invasive coronary angiography and DCMR-negative patients received optimal medical treatment. Of 609 (40%) DCMR-positive patients coronary angiography was performed in 478 (78%) within 90 days. In 409 of these patients significant coronary stenoses ≥ 50% were present (positive predictive value 86%). Of 923 (60%) DCMR-negative patients 833 (90%) received optimal medical therapy. During a mean follow-up period of 2.1 ± 0.8 years (median: 2.1 years, interquartile range 1.5 to 2.7 years) 8 DCMR-negative patients (0.96%) sustained a cardiac event.In 131 DCMR-positive patients who did not undergo invasive angiography, 20 patients (15%) suffered cardiac events. In 90 DCMR-negative patients (10%) invasive angiography was performed within 2 years (range 0.01 to 2.0 years) with 56 patients having coronary stenoses ≥ 50%.

CONCLUSION

In a routine setting DCMR proved a useful arbiter for clinical decision making and exhibited high utility for stratification and clinical management of patients with suspected and known CAD.

Prognostic value of routine cardiac magnetic resonance assessment of left ventricular ejection fraction and myocardial damage: an international, multicenter study

BACKGROUND

Cardiac magnetic resonance (CMR) is considered the reference standard for assessment of left ventricular ejection fraction (LVEF) and myocardial damage. However, few studies have evaluated the relationship between CMR findings and patient outcome, and of these, most are small and none multicenter. We performed an international, multicenter study to assess the prognostic importance of routine CMR in patients with known or suspected heart disease.

METHODS AND RESULTS

From 10 centers in 6 countries, consecutive patients undergoing routine CMR assessment of LVEF and myocardial damage by cine and delayed-enhancement imaging (DE-CMR), respectively, were screened for enrollment. Clinical data, CMR protocol information, and findings were collected at all sites and submitted to the data coordinating center for verification of completeness and analysis. The primary end point was all-cause mortality. A total of 1560 patients (age, 59±14 years; 70% men) were enrolled. Mean LVEF was 45±18%, and 1049 (67%) patients had hyperenhanced tissue (HE) on DE-CMR indicative of damage. During a median follow-up time of 2.4 years (interquartile range, 1.2, 2.9 years), 176 (11.3%) patients died. Patients who died were more likely to be older (P<0.0001), have coronary disease (P=0.004), have lower LVEF (P<0.0001), and have more segments with HE (P<0.0001). In multivariable analysis, age, LVEF, and number of segments with HE were independent predictors of mortality. Among patients with near-normal LVEF (≥50%), those with above-median HE (>4 segments) had reduced survival compared to patients with below- or at-median HE (P=0.02).

CONCLUSIONS

Both LVEF and amount of myocardial damage as assessed by routine CMR are independent predictors of all-cause mortality. Even in patients with near-normal LVEF, significant damage identifies a cohort with a high risk for early mortality.

Novel therapies in childhood heart failure: today and tomorrow

Heart failure is an important cause of morbidity and mortality in individuals of all ages. The many-faceted nature of the clinical heart failure syndrome has historically frustrated attempts to develop an overarching explanative theory. However, much useful information has been gained by basic and clinical investigation, even though a comprehensive understanding of heart failure has been elusive. Heart failure is a growing problem, in both adult and pediatric populations, for which standard medical therapy, as of 2010, can have positive effects, but these are usually limited and progressively diminish with time in most patients. If we want curative or near-curative therapy that will return patients to a normal state of health at a feasible cost, much better diagnostic and therapeutic technologies need to be developed. This review addresses the vexing group of heart failure etiologies that include cardiomyopathies and other ventricular dysfunctions of various types, for which current therapy is only modestly effective. Although there are many unique aspects to heart failure in patients with pediatric and congenital heart disease, many of the innovative approaches that are being developed for the care of adults with heart failure will be applicable to heart failure in childhood.

[Detection of induced myocardial ischemia during stress cardiovascular magnetic resonance]

In the past decade, cardiovascular magnetic resonance (CMR) has evolved considerably. Its clinical applications enable the diagnosis and prognostic assessment of patients with ischemic heart disease. CMR is safe, with absence of any ionizing radiation, and offers the greatest information from a single test, allowing the assessment of myocardial morphology, myocardial function and viability. Stress-CMR can be used for detection and quantification of ischemia. This article analyses the technical approach, the limits and reviews the available literature about diagnostic performance of stress CMR testing and its results in the prognostication of cardiac patients. With further improvements in CMR techniques and the establishment of a standardized study protocol, stress-CMR will play a pivotal role in managing patients with ischemic heart disease.

Cardiac magnetic resonance imaging as a prognostic tool in patients with nonischemic cardiomyopathy

Technical advancements have enabled cardiac magnetic resonance (CMR) imaging to provide a noninvasive assessment of cardiomyopathy. Cardiac magnetic resonance imaging acts as the reference standard for quantifying left and right ventricular function. It also assesses the etiology of cardiomyopathy by demonstrating the presence and size of myocardial scar and by detecting myocardial inflammation and interstitial infiltration. Cardiomyopathy can result in early mortality and arrhythmic risk, and CMR imaging aids in risk stratification among this group of patients. Left ventricular ejection fraction predicts which patients will benefit most from implantable cardioverter-defibrillators (ICDs), but this is not a perfect marker of arrhythmic risk. The etiology of cardiomyopathy, as assessed with CMR imaging, adds further prognostic information with infiltrative cardiomyopathies, resulting in higher mortality than idiopathic cardiomyopathies. Among patients with nonischemic cardiomyopathy (NICM), the degree of fibrosis as determined by the CMR imaging sequence of late gadolinium enhancement (LGE) imaging offers further prognostic information. Late gadolinium enhancement imaging in patients with NICM portends an approximately 3- to 8-fold greater risk of death or hospitalization than NICM without LGE imaging. Further research is needed to determine if the presence of LGE will be helpful in predicting which patients may benefit from ICD implantation.