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Dive into the research topics where Allison A. Merz is active.

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Featured researches published by Allison A. Merz.


European Heart Journal | 2016

Detection and prognostic value of pulmonary congestion by lung ultrasound in ambulatory heart failure patients

Elke Platz; Eldrin F. Lewis; Hajime Uno; Julie Peck; Emanuele Pivetta; Allison A. Merz; Dorothea Hempel; Christina Wilson; Sarah E. Frasure; Pardeep S. Jhund; Susan Cheng; Scott D. Solomon

AIMS Pulmonary congestion is a common and important finding in heart failure (HF). While clinical examination and chest radiography are insensitive, lung ultrasound (LUS) is a novel technique that may detect and quantify subclinical pulmonary congestion. We sought to independently relate LUS and clinical findings to 6-month HF hospitalizations and all-cause mortality (composite primary outcome). METHODS We used LUS to examine 195 NYHA class II-IV HF patients (median age 66, 61% men, 74% white, ejection fraction 34%) during routine cardiology outpatient visits. Lung ultrasound was performed in eight chest zones with a pocket ultrasound device (median exam duration 2 min) and analysed offline. RESULTS In 185 patients with adequate LUS images in all zones, the sum of B-lines (vertical lines on LUS) ranged from 0 to 13. B-lines, analysed by tertiles, were associated with clinical and laboratory markers of congestion. Thirty-two per cent of patients demonstrated ≥3 B-lines on LUS, yet 81% of these patients had no findings on auscultation. During the follow-up period, 50 patients (27%) were hospitalized for HF or died. Patients in the third tertile (≥3 B-lines) had a four-fold higher risk of the primary outcome (adjusted HR 4.08, 95% confidence interval, CI 1.95, 8.54; P < 0.001) compared with those in the first tertile and spent a significantly lower number of days alive and out of the hospital (125 days vs. 165 days; adjusted P < 0.001). CONCLUSIONS Pulmonary congestion assessed by ultrasound is prevalent in ambulatory patients with chronic HF, is associated with other features of clinical congestion, and identifies those who have worse prognosis.


Heart | 2016

Sex differences in cardiovascular ageing.

Allison A. Merz; Susan Cheng

Despite recent progress in identifying and narrowing the gaps in cardiovascular outcomes between men and women, general understanding of how and why cardiovascular disease presentations differ between the sexes remains limited. Sex-specific patterns of cardiac and vascular ageing play an important role and, in fact, begin very early in life. Differences between the sexes in patterns of age-related cardiac remodelling are associated with the relatively greater prevalence in women than in men of heart failure with preserved ejection fraction. Similarly, sex variation in how vascular structure and function change with ageing contributes to differences between men and women in how coronary artery disease manifests typically or atypically over the adult life course. Both hormonal and non-hormonal factors underlie sex differences in cardiovascular ageing and the development of age-related disease. The midlife withdrawal of endogenous oestrogen appears to augment the age-related increase in cardiovascular risk seen in postmenopausal compared with premenopausal women. However, when compared with intrinsic biological differences between men and women that are present throughout life, this menopausal transition may not be as substantial an actor in determining cardiovascular outcomes.


European Heart Journal | 2015

Haeme oxygenase signalling pathway: implications for cardiovascular disease

Allison A. Merz; Susan Cheng

Evidence now points to the haeme oxygenase (HO) pathway as a possible actor in modulating risk for cardiovascular disease (CVD). In particular, the HO pathway may represent a key endogenous modulator of oxidative, inflammatory, and cytotoxic stress while also exhibiting vasoregulatory properties. In this review, we summarize the accumulating experimental and emerging clinical data indicating how activity of the HO pathway and its products may play a role in mechanisms underlying the development of CVD. We also identify gaps in the literature to date and suggest future directions for investigation. Because HO pathway activity can be influenced not only by genetic traits and environmental stimuli but also by a variety of existing pharmacologic interventions, the pathway could serve as a prime target for reducing the overall burden of CVD. Further work is needed to determine the role of HO pathway products as possible prognostic markers of risk for clinical CVD events and the extent to which therapeutic augmentation or inhibition of HO pathway activity could serve to modify CVD risk.


Journal of the American Heart Association | 2015

Distinct Aspects of Left Ventricular Mechanical Function Are Differentially Associated With Cardiovascular Outcomes and All‐Cause Mortality in the Community

Susan Cheng; Elizabeth L. McCabe; Martin G. Larson; Allison A. Merz; Ewa Osypiuk; Birgitta Lehman; Plamen Stantchev; Jayashri Aragam; Scott D. Solomon; Emelia J. Benjamin

Background There are few data relating novel measures of left ventricular (LV) mechanical function to cardiovascular disease (CVD) outcomes in the community. Whether distinct components of LV mechanical function provide information regarding risk for different CVD outcomes is unclear. Methods and Results We used speckle tracking echocardiography to quantify distinct components of LV mechanical function (measured as LV strain in multiple planes) in 2831 Framingham Offspring Study participants (mean age, 66 years; 57% women, 97% with LV fractional shortening >0.29). Participants were followed for 6.0±1.2 years for onset of 69 coronary heart disease (CHD), 71 heart failure (HF), and 199 mortality events. Adjusting for CVD risk factors, longitudinal LV strain appeared associated with incident CHD (hazards ratio [HR] per SD increment, 1.29; 95% confidence interval [CI], 1.00–1.67; P=0.05), whereas circumferential and radial strain were not (P>0.37 for both); however, the association of longitudinal strain with CHD was nonsignificant after Bonferroni correction. By contrast, circumferential strain was a significant predictor of incident HF (HR per SD increment, 1.79; 95% CI, 1.35–2.37; P<0.0001). Decrements in circumferential, radial, and longitudinal strain measures were related to all‐cause mortality (P<0.008 for all). Results remained similar in multivariable models adjusting additionally for the conventional echocardiographic measures of LV mass and fractional shortening. Conclusions In our large, community‐based sample, distinct components of LV mechanical function were associated with specific CVD outcomes. Additional studies are needed to replicate these findings and investigate the prognostic and therapeutic utility of these novel measures of LV mechanical function.


European Journal of Heart Failure | 2017

Dynamic changes and prognostic value of pulmonary congestion by lung ultrasound in acute and chronic heart failure: a systematic review.

Elke Platz; Allison A. Merz; Pardeep S. Jhund; Ali Vazir; Ross T. Campbell; John J.V. McMurray

Pulmonary congestion is an important finding in patients with heart failure (HF) that can be quantified by lung ultrasound (LUS). We conducted a systematic review to describe dynamic changes in LUS findings of pulmonary congestion (B‐lines) in HF and to examine the prognostic utility of B‐lines in HF.


American Journal of Emergency Medicine | 2015

Impact of device selection and clip duration on lung ultrasound assessment in patients with heart failure.

Elke Platz; Emanuele Pivetta; Allison A. Merz; Julie Peck; Jose Rivero; Susan Cheng

OBJECTIVES Pulmonary edema is a common sign of heart failure and can be quantified by counting vertical artifacts (B-lines) on lung ultrasound (LUS). The primary aim of this study was to compare a pocket size ultrasound device to high-end ultrasound systems on the measured number of B-lines. We also compared the impact of different-length ultrasound clips on the measured number of B-lines. METHODS AND RESULTS We studied 21 hospitalized patients with heart failure (81% men; median age, 73; 71% Caucasian) who underwent concurrent 8- and 4-zone LUS using both a pocket ultrasound device and a high-end ultrasound system. For the 4-zone scanning method, the median B line number was 2 (interquartile range, 1-4) for the pocket device and 3 (1-5) for the high-end system (P = .67). For the 8-zone method, the median B-line number was 4 (2-7) for the pocket device and 5 (3-7) for the high-end system (P = .18). A higher number of B-lines was identified on the 4- vs 2-second LUS clips (P < .001 for 4 zones, P = .001 for 8 zones), and on the 6- vs 4-second LUS clips (P=0.057 for 4 zones, P=0.018 for 8 zones). CONCLUSIONS Our findings suggest significant differences based on LUS clip duration rather than the type of ultrasound device used, with respect to the number of B-lines detectable in patients with heart failure. These factors should be considered in the design and reporting of LUS studies and in longitudinal assessments of heart failure patients.


Journal of the American Heart Association | 2017

Relations Between Aortic Stiffness and Left Ventricular Mechanical Function in the Community

Vanessa Bell; Elizabeth L. McCabe; Martin G. Larson; Jian Rong; Allison A. Merz; Ewa Osypiuk; Birgitta Lehman; Plamen Stantchev; Jayashri Aragam; Emelia J. Benjamin; Naomi M. Hamburg; Gary F. Mitchell; Susan Cheng

Background Aortic stiffness impairs optimal ventricular–vascular coupling and left ventricular systolic function, particularly in the long axis. Left ventricular global longitudinal strain (GLS) has recently emerged as a sensitive measure of early cardiac dysfunction. In this study, we investigated the relation between aortic stiffness and GLS in a large community‐based sample. Methods and Results In 2495 participants (age 39–90 years, 57% women) of the Framingham Offspring and Omni cohorts, free of cardiovascular disease, we performed tonometry to measure arterial hemodynamics and echocardiography to assess cardiac function. Aortic stiffness was evaluated as carotid–femoral pulse wave velocity and as characteristic impedance, and GLS was calculated using speckle tracking–based measurements. In multivariable analyses adjusting for age, sex, height, systolic blood pressure, augmentation index, left ventricular structure, and additional cardiovascular risk factors, increased carotid–femoral pulse wave velocity (B±SE: 0.122±0.030% strain per SD, P<0.0001) and characteristic impedance (0.090±0.029, P=0.002) were both associated with worse GLS. We observed effect modification by sex on the relation between characteristic impedance and GLS (P=0.004); in sex‐stratified multivariable analyses, the relation between greater characteristic impedance and worse GLS persisted in women (0.145±0.039, P=0.0003) but not in men (P=0.73). Conclusions Multiple measures of increased aortic stiffness were cross‐sectionally associated with worse GLS after adjusting for hemodynamic variables. Parallel reductions in left ventricular long axis shortening and proximal aortic longitudinal strain in individuals with a stiffened proximal aorta, from direct mechanical ventricular‐vascular coupling, offers an alternative explanation for the observed relations.


Journal of Cardiac Failure | 2018

Pulmonary Congestion by Lung Ultrasound in Ambulatory Patients With Heart Failure With Reduced or Preserved Ejection Fraction and Hypertension

Kristin H. Dwyer; Allison A. Merz; Eldrin F. Lewis; Brian Claggett; Daniela R. Crousillat; Emily S. Lau; Montane B. Silverman; Julie Peck; Jose Rivero; Susan Cheng; Elke Platz

BACKGROUND Although pulmonary congestion can be quantified in heart failure (HF) by means of lung ultrasonography (LUS), little is known about LUS findings (B-lines) in different HF phenotypes. This prospective cohort study investigated the prevalence and clinical and echocardiographic correlates of B-lines in ambulatory HF patients with preserved (HFpEF) or reduced (HFrEF) ejection fraction compared with hypertensive patients. We related LUS findings to 12-month HF hospitalizations and all-cause mortality. METHODS AND RESULTS We used LUS to examine hypertensive (n = 111), HFpEF (n = 46), and HFrEF (n = 73) patients (median age 66 y, 56% male, 79% white, and median EF 55%) undergoing clinically indicated outpatient echocardiography. B-line number was quantified offline, across 8 chest zones, blinded to clinical and echocardiographic characteristics. The proportion of patients with ≥3 B-lines was lower in hypertensive patients (13.5%) compared with both HFrEF (45.2%, P < .001) and HFpEF (34.8%; P = .05). HF patients with ≥3 B-lines had a higher risk of the composite outcome (age- and sex-adjusted hazard ratio 2.62, 95% confidence interval 1.15-5.96; P = .022). CONCLUSIONS When performed at the time of outpatient echocardiography, LUS findings of pulmonary congestion differ between patients with known HF and those with hypertension, and may be associated with adverse outcomes.


Echocardiography-a Journal of Cardiovascular Ultrasound and Allied Techniques | 2018

Right atrial structure and function in patients with hypertension and with chronic heart failure

Moritz Proplesch; Allison A. Merz; Brian Claggett; Eldrin F. Lewis; Kristin H. Dwyer; Daniela R. Crousillat; Emily S. Lau; Montane B. Silverman; Julie Peck; Jose Rivero; Susan Cheng; Elke Platz

Prior studies have shown that both heart failure (HF) and atrial fibrillation (AF) are factors that impact left atrial function and structure. However, right atrial (RA) function measured as RA emptying fraction (RAEF) on echocardiography has not been analyzed systematically in a chronic HF population. The aim of this study was to assess RA volume index (RAVI) and RAEF in patients with chronic HF and patients with hypertension (HTN) and to relate these findings to other cardiopulmonary ultrasound parameters and 12‐month outcomes.


Heart | 2016

Regarding sex differences in cardiovascular ageing: let us not forget iron

Allison A. Merz; Susan Cheng

The Authors’ reply We thank Dr Goldstein1 for bringing to our attention the iron hypothesis as a potential non-hormonal factor contributing to sex differences in cardiovascular ageing. We also find intriguing the possibility that iron depletion in menstruating women may be cardioprotective. We had previously been aware of the potential role of iron as a by-product of haeme …

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Susan Cheng

Brigham and Women's Hospital

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Elke Platz

Brigham and Women's Hospital

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Julie Peck

Royal College of Surgeons in Ireland

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Eldrin F. Lewis

Brigham and Women's Hospital

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Jose Rivero

Brigham and Women's Hospital

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