Michael Salerno

Prognostic Value of Late Gadolinium Enhancement in Clinical Outcomes for Hypertrophic Cardiomyopathy

OBJECTIVESnThe objective of this study was to perform a systematic review and meta-analysis of the predictive value of late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) for future cardiovascular events and death in hypertrophic cardiomyopathy (HCM).nnnBACKGROUNDnThe utility of LGE for detecting myocardial fibrosis is well established. The prognostic value of LGE in HCM has been described in several studies, but controversy exists given the limited power of these studies to predict future events.nnnMETHODSnWe searched multiple databases including PubMed for studies of LGE in HCM that reported selected clinical outcomes (cardiovascular mortality, sudden cardiac death [SCD], aborted SCD, and heart failure death). We performed a systematic review of the literature and meta-analysis to determine pooled odds ratios for these clinical events.nnnRESULTSnFour studies evaluated 1,063 patients over an average follow-up of 3.1 years. The pooled prevalence of LGE was 60%. The pooled odds ratios (OR) demonstrate that LGE by CMR correlated with cardiac death (pooled OR: 2.92, 95% confidence interval [CI]: 1.01 to 8.42; p = 0.047), heart failure death (pooled OR: 5.68, 95% CI: 1.04 to 31.07; p = 0.045), and all-cause mortality (pooled OR: 4.46, 95% CI: 1.53 to 13.01; p = 0.006), and showed a trend toward significance for predicting sudden death/aborted sudden death (pooled OR: 2.39, 95% CI: 0.87 to 6.58; p = 0.091).nnnCONCLUSIONSnLate gadolinium enhancement by CMR has prognostic value in predicting adverse cardiovascular events among HCM patients. There are significant relationships between LGE and cardiovascular mortality, heart failure death, and all-cause mortality in HCM. Additionally, LGE and SCD/aborted SCD displayed a trend toward significance. The assessment of LGE by CMR has the potential to provide important information to improve risk stratification in HCM in clinical practice.

Noninvasive Assessment of Myocardial Perfusion

Noninvasive assessment of myocardial perfusion is important in the diagnosis and risk stratification of patients with known or suspected coronary artery disease (CAD). Although single-photon emission computed tomography (SPECT) is most commonly used, multiple modalities including myocardial contrast echocardiography (MCE), positron emission tomography (PET), cardiac MRI (CMR), and cardiac computed tomography (CT) have emerged as promising techniques. This article will critically evaluate the strengths and weakness of these modalities for evaluating myocardial perfusion.nnMyocardial perfusion is a highly regulated process that includes epicardial vessels, resistance vessels, and the endothelium. Endothelial dysfunction is an early manifestation of vascular disease and plays a role in the development of CAD.1 In normal coronaries, sympathetic stimulation causes a flow-mediated endothelium-dependent release of nitric oxide resulting in epicardial and arteriolar vasodilation. With endothelial dysfunction, vasoconstriction from acetylcholine predominates, resulting an attenuation or absence of the normal flow-mediated vasodilation.2 When coronary arteries are narrowed by atherosclerotic disease, coronary autoregulation attempts to normalize myocardial blood flow by reducing the resistance of distal perfusion beds to preserve adequate myocardial oxygen supply.3 A stenosis must exceed 85% to 90% of luminal diameter before significant reductions in resting blood flow occur.4 However, under vasodilator stimulus, maximal coronary flow has been shown to decrease with stenosis of >45% (Figure 1).4 This has been demonstrated clinically using quantitative PET myocardial perfusion imaging (MPI).5,6 Because perfusion is an early change in the ischemic cascade,7 stress modalities that assess coronary perfusion reserve have a higher sensitivity in detecting flow-limiting stenoses than analysis of stress-induced wall motion abnormalities or ECG changes alone.8 Abnormal coronary flow reserve with vasodilator stress in the absence of a significant coronary stenosis occurs and has been attributed to microvascular and/or endothelial dysfunction.9 nnnnFigure 1. Relationship between percent diameter stenosis and …

Non-invasive imaging and monitoring cardiotoxicity of cancer therapeutic drugs

Cardiotoxicity due to administration of cancer therapeutic agents such as anthracyclines and herceptin are well described. Established guidelines to screen for chemotherapy-related cardiotoxicity (CRC) are primarily based on serial assessment of left ventricular (LV) ejection fraction (EF). However, other parameters such as LV volume, diastolic function, and strain may also be useful in screening for cardiotoxicity. More recent advances in molecular imaging of apoptosis and tissue characterization by cardiac MRI are techniques which might allow early detection of patients at high risk for developing cardiotoxicity prior to a drop in EF. This comprehensive multi-modality review will discuss both the current established imaging techniques as well as the emerging technologies which may revolutionize the future of screening and evaluation for CRC.

Optimization of spiral‐based pulse sequences for first‐pass myocardial perfusion imaging

Although spiral trajectories have multiple attractive features such as their isotropic resolution, acquisition efficiency, and robustness to motion, there has been limited application of these techniques to first‐pass perfusion imaging because of potential off‐resonance and inconsistent data artifacts. Spiral trajectories may also be less sensitive to dark‐rim artifacts that are caused, at least in part, by cardiac motion. By careful consideration of the spiral trajectory readout duration, flip angle strategy, and image reconstruction strategy, spiral artifacts can be abated to create high‐quality first‐pass myocardial perfusion images with high signal‐to‐noise ratio. The goal of this article was to design interleaved spiral pulse sequences for first‐pass myocardial perfusion imaging and to evaluate them clinically for image quality and the presence of dark‐rim, blurring, and dropout artifacts. Magn Reson Med, 2011.

Elevated circulating fibrocyte levels in patients with hypertensive heart disease

Objective: Autopsy and biopsy studies have shown that there is significantly more fibrosis in hearts of patients with hypertensive heart disease compared to normal hearts. Fibrocytes, a population of circulating bone marrow-derived cells, have been shown to home to tissues and promote scar formation in several diseases, but their role in human hypertensive heart disease has not been investigated to date. Our objective was to determine whether fibrocyte levels are elevated in individuals with hypertensive heart disease. Methods: We measured peripheral blood fibrocyte levels and their activated phenotypes in 12 individuals with hypertensive heart disease as determined by increased left ventricular mass on noninvasive imaging and compared them to fibrocyte levels from 19 healthy normal controls and correlated them to cardiac MRI findings. Results: Compared to normal controls, individuals with hypertensive heart disease had significantly higher circulating levels of total fibrocytes [median (interquartile range); 149000 (62200–220000) vs. 564500 (321000–1.2900e+006), Pu200a<u200a0.0001, respectively] as well as activated fibrocytes [15700 (6380–19800) vs. 478500 (116500–1.2360e+006) Pu200a<u200a0.0001]. Moreover, the fibrocyte subsets expressing the chemokine markers CXCR4 (Pu200a<u200a0.0001), CCR2 (Pu200a<u200a0.0001), CCR7 (Pu200a<u200a0.0001) and coexpression of both CXCR4 and CCR2 (Pu200a<u200a0.0001) were significantly elevated in patients with hypertensive heart disease compared to controls. Lastly, in patients with hypertensive heart disease there was a strong correlation between left ventricular mass index and total fibrocytes (ru200a=u200a0.65, Pu200a=u200a0.037) and activated fibrocytes (ru200a=u200a0.70, Pu200a=u200a0.016). Conclusion: Our data suggest that bone marrow-derived circulating fibrocytes are associated with the presence and extent of left ventricular hypertrophy in patients with hypertensive heart disease.

Prognosis in hypertrophic cardiomyopathy with contrast-enhanced cardiac magnetic resonance: the future looks bright.

Hypertrophic cardiomyopathy (HCM) is the most common genetic cause of heart disease and the most frequent cause of sudden cardiac death (SCD) in young people ([1][1]). Determining which patients are at higher risk of the development of adverse outcomes, particularly SCD, remains challenging. The

Prevalence and distribution of regional scar in dysfunctional myocardial segments in Duchenne muscular dystrophy

BackgroundThe segmental relationship between cardiovascular magnetic resonance (CMR) peak circumferential strain (Ecc) and myocardial scar has not been well characterized in Duchenne muscular dystrophy (DMD), and it is unknown whether echocardiography accurately measures Ecc in DMD. We assessed segmental Ecc and scar using CMR with myocardial tissue tagging and late gadolinium enhancement (LGE) in patients with DMD, then compared CMR with echocardiographic velocity vector imaging (VVI) for regional Ecc based on independent observer assessments.ResultsParticipants enrolled (n = 16; age 8-23) had median left ventricular (LV) ejection fraction of 0.52 (range 0.28-0.69), and 156 basal and mid-cavity myocardial segments from the 13 patients completing the LGE protocol were analyzed for strain and scar. Segmental CMR Ecc in the most negative quartile (quartile 4) ruled out scar in that segment, but scar was present in 46% of segments in the least negative (most dysfunctional) Ecc quartile 1, 33% of Ecc quartile 2 segments, and 15% of Ecc quartile 3 segments. Overall scar prevalence in inferior, inferolateral, and anterolateral segments was eight times higher than in inferoseptal, anteroseptal, and anterior segments (p < 0.001). This increased proportion of scar in lateral versus septal segments was consistent across CMR Ecc quartiles (quartile 1: 76% versus 11%, p = 0.001; quartile 2: 65% versus 9%, p < 0.001; quartile 3: 38% versus 0%, p < 0.001). Echocardiographic analysis could be performed in 12 of 14 patients with CMR exams and had to be limited to mid-cavity slices. Echo segmental Ecc in the most negative quartile made scar by CMR in that segment highly unlikely, but the correlation in segmental Ecc between CMR and echo was limited (r = 0.27; p = 0.02).ConclusionsThe relationship between scar and Ecc in DMD is complex. Among myocardial segments with depressed Ecc, scar prevalence was much higher in inferior, inferolateral, and anterolateral segments, indicating a regionally dependent association between abnormal Ecc and scar, with free wall segments commonly developing dysfunction with scar and septal segments developing dysfunction without scar. Although normal echocardiographic Ecc predicted absence of scar, regional echocardiographic Ecc by VVI has only a limited association with CMR Ecc in DMD.

Multi-modality imaging of diastolic function

Non-invasive evaluation of diastolic function continues to play a critical role in furthering our understanding of diastole, improving the diagnosis of diastolic dysfunction, evaluating left ventricular filling pressures, and providing important prognostic information for patients with heart failure. Echocardiography, cardiovascular magnetic resonance, and nuclear cardiology each provide important tools for evaluating diastolic performance. This review will focus on the techniques from multiple cardiovascular imaging modalities which have been used for the clinical assessment of diastolic function.

Coronary angiographic evaluation of low-risk chest pain in the emergency department CT-STAT, or maybe not quite that fast?

Coronary computed tomographic angiography (CCTA) is evolving into a mature imaging modality for assessment of patients with acute chest pain in the emergency department (ED). More than 1,000 patients have been studied in the ED setting in both single-center and multicenter trials, not including the

Prognostic validation of an algorithm to convert myocardial perfusion SPECT imaging data from a 12-segment model to a 17-segment model

BackgroundA 17-segment model has become the standard for interpreting myocardial perfusion single-photon emission computed tomography (SPECT). Methods for converting pre-existing databases from 12-segment models to the 17-segment model are needed for ongoing prognostic studies.Methods and ResultsTo develop the conversion algorithm, 150 consecutive SPECT studies (82 abnormal) were read by both a 12-segment and the standard 17-segment models. Summed stress scores (SSSs) were calculated from a 17-segment model derived from the 12-segment data and compared to those of the standard 17-segment model. The effect of the conversion algorithm on prognostic data derived from the 12-segment model was evaluated in 25,876 patients from the Duke Nuclear Cardiology Database, including a sample of 3,205 patients with known covariates for adjusted analysis. The derived 17-segment SSS from the 12-segment model was highly correlated (Rxa0=xa00.99) to the SSS from the standard 17-segment model. In both unadjusted and adjusted analysis, there was no difference in the prognostic information.ConclusionsAn algorithm for conversion of 12-segment perfusion scores to 17-segment scores has been developed which is highly correlated to visual interpretation by the 17-segment model with nearly identical prognostic information.