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1.  Tricuspid Annular Plane Systolic Excursion in the Assessment of Right Ventricular Function in Children and Adolescents after Repair of Tetralogy of Fallot 
Assessing right ventricular (RV) performance is essential for patients with tetralogy of Fallot (TOF). The aim of this study was to investigate the reliability and validity of tricuspid annular plane systolic excursion (TAPSE) against cardiac magnetic resonance imaging measures and cardiopulmonary exercise testing.
A retrospective study was performed in 125 outpatients with repaired TOF with available protocoldriven echocardiography, cardiac magnetic resonance imaging, and exercise stress testing obtained as part of a cross-sectional study. TAPSE was measured on the two-dimensional apical four-chamber view on echocardiography by two readers. Multivariate linear regression was used to examine the association between TAPSE and measures of RV function and exercise capacity.
The mean age was 12.6 ± 3.3 years, 41 patients (33%) were female, and 104 (83%) were white. TAPSE averaged 1.6 ± 0.37 cm, with an interreader intraclass correlation coefficient of 0.78 (n = 18). TAPSE was significantly associated with cardiac magnetic resonance–based RV stroke volume after adjustment for gender and body surface area (β = 13.8; 95% confidence interval, 2.25–25.30; P = .02). TAPSE was not associated with cardiac magnetic resonance–based RV ejection fraction (P = .77). On exercise testing, TAPSE was not associated with peak oxygen consumption, percentage of predicted oxygen consumption, oxygen pulse, or the ventilatory equivalent for carbon dioxide in patients with maximal exercise stress testing (n = 73 [58%]).
TAPSE is reproducibly measured by echocardiography in patients with TOF. It is not associated with RV ejection fraction or exercise performance, and its association with RV stroke volume may be confounded by body size. On the basis of these results, TAPSE is not representative of global RV performance in patients with TOF.
PMCID: PMC4336673  PMID: 23928091
Tricuspid annular plane systolic excursion; Echocardiography; Exercise; Magnetic resonance imaging; Tetralogy of Fallot
2.  Relationship of CRP, IL-6, and Fibrinogen with Right Ventricular Structure and Function: The MESA-Right Ventricle Study 
International journal of cardiology  2013;168(4):3818-3824.
Inflammation contributes to the pathogenesis of disease associated with the left ventricle (LV); yet, our understanding of the effect of inflammation on the right ventricle (RV) is quite limited.
Methods and results
The relationships of C-reactive protein (CRP), interleukin-6 (IL-6) and fibrinogen with RV morphology and function (from cardiac MRI) were examined in participants free of clinical cardiovascular disease (n=4,009) from the Multi-Ethnic Study of Atherosclerosis (MESA)-RV study. Multivariable regressions (linear, quantile [25th and 75th] and generalized additive models [GAM]) were used to examine the independent association of CRP, IL-6 and fibrinogen with RV mass, RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), RV stroke volume (RVSV) and RV ejection fraction (RVEF). Unadjusted and adjusted analyses revealed strong inverse associations between both CRP and IL-6 with RV mass, RVEDV, RVESV and RVSV (all p<0.01); there were no associations with RVEF. These relationships remained significant after adjustment for the respective LV parameters and lung function. However, GAM models suggested that extreme values of CRP and IL-6 might have positive associations with RV parameters. Fibrinogen showed significant associations in unadjusted models, but no associations after adjustment or in sensitivity analyses.
Levels of CRP and IL-6 are independently associated with RV morphology even after adjustment for the respective LV measure in this multi-ethnic population free of cardiovascular disease. Systemic inflammation may contribute to RV structural changes independent of effects on the LV.
PMCID: PMC3805818  PMID: 23932860
Systemic inflammation; right ventricle; heart failure; Multi-Ethnic Study of Atherosclerosis
3.  An Official American Thoracic Society Statement: Pulmonary Hypertension Phenotypes 
Background: Current classification of pulmonary hypertension (PH) is based on a relatively simple combination of patient characteristics and hemodynamics. This limits customization of treatment, and lacks the clarity of a more granular identification based on individual patient phenotypes. Rapid advances in mechanistic understanding of the disease, improved imaging methods, and innovative biomarkers now provide an opportunity to define PH phenotypes on the basis of biomarkers, advanced imaging, and pathobiology. This document organizes our current understanding of PH phenotypes and identifies gaps in our knowledge.
Methods: A multidisciplinary committee with expertise in clinical care (pulmonary, cardiology, pediatrics, and pathology), clinical research, and/or basic science in the areas of PH identified important questions and reviewed and synthesized the literature.
Results: This document describes selected PH phenotypes and serves as an initial platform to define additional relevant phenotypes as new knowledge is generated. The biggest gaps in our knowledge stem from the fact that our present understanding of PH phenotypes has not come from any particularly organized effort to identify such phenotypes, but rather from reinterpreting studies and reports that were designed and performed for other purposes.
Conclusions: Accurate phenotyping of PH can be used in research studies to increase the homogeneity of study cohorts. Once the ability of the phenotypes to predict outcomes has been validated, phenotyping may also be useful for determining prognosis and guiding treatment. This important next step in PH patient care can optimally be addressed through a consortium of study sites with well-defined goals, tasks, and structure. Planning and support for this could include the National Institutes of Health and the U.S. Food and Drug Administration, with industry and foundation partnerships.
PMCID: PMC4291177  PMID: 24484330
biomarkers; consortium; metabolism; pathobiology; pulmonary circulation
4.  Pentraxin-3 and the right ventricle: the Multi-Ethnic Study of Atherosclerosis–Right Ventricle Study 
Pulmonary Circulation  2014;4(2):250-259.
Pentraxin-3 (PTX3) is a protein mediator of innate immunity that is elevated in the setting of left heart disease and pulmonary arterial hypertension. The relationship between PTX3 and right ventricular (RV) structure and function is not known. We included men and women with magnetic resonance imaging assessment of RV structure and function and measurement of PTX3 from the Multi-Ethnic Study of Atherosclerosis, a study of individuals free of clinical cardiovascular disease. Multivariable linear regression estimated associations between PTX3 protein levels and RV measures after adjusting for demographic characteristics, anthropometrics, smoking status, diabetes mellitus, hypertension, and corresponding left ventricular (LV) parameters. Instrumental variable analysis exploiting Mendelian randomization was attempted using two-stage least squares regression. The study sample included 1,779 participants with available PTX3 levels, RV measures, and all covariables. Mean PTX3 level was 2.1 ng/mL. Higher PTX3 was independently associated with greater RV mass and larger RV end-diastolic volume with and without adjustment for the corresponding LV parameters or C-reactive protein (all P < .05). There was no association between PTX3 and RV ejection fraction or stroke volume. Single-nucleotide polymorphisms were not associated with PTX3 protein levels or RV measures after accounting for race. Instrumental variable analysis could not be reliably performed. Higher PTX3 protein levels were associated with greater RV mass and larger RV end-diastolic volume. These associations were independent of common cardiovascular risk factors and LV morphologic changes. Inflammation is associated with differences in the pulmonary circulation-RV axis in adults without clinical cardiovascular disease.
PMCID: PMC4070771  PMID: 25006444
pulmonary hypertension; heart failure; inflammation; right ventricle; Mendelian randomization
5.  Validation of 6-Minute Walk Distance as a Surrogate End Point in Pulmonary Arterial Hypertension Trials 
Circulation  2012;126(3):349-356.
Nearly all available treatments for pulmonary arterial hypertension have been approved based on change in 6-minute walk distance (Δ6MWD) as a clinically important end point, but its validity as a surrogate end point has never been shown. We aimed to validate the difference in Δ6MWD against the probability of a clinical event in pulmonary arterial hypertension trials.
Methods and Results
First, to determine whether Δ6MWD between baseline and 12 weeks mediated the relationship between treatment assignment and development of clinical events, we conducted a pooled analysis of patient-level data from the 10 randomized placebo-controlled trials previously submitted to the US Food and Drug Administration (n=2404 patients). Second, to identify a threshold effect for the Δ6MWD that indicated a statistically significant reduction in clinical events, we conducted a meta-regression among 21 drug/dose-level combinations. Δ6MWD accounted for 22.1% (95% confidence interval, 12.1%– 31.1%) of the treatment effect (P<0.001). The meta-analysis showed an average difference in Δ6MWD of 22.4 m (95% confidence interval, 17.4–27.5 m), favoring active treatment over placebo. Active treatment decreased the probability of a clinical event (summary odds ratio, 0.44; 95% confidence interval, 0.33–0.57). The meta-regression revealed a significant threshold effect of 41.8 m.
Our results suggest that Δ6MWD does not explain a large proportion of the treatment effect, has only modest validity as a surrogate end point for clinical events, and may not be a sufficient surrogate end point. Further research is necessary to determine whether the threshold value of 41.8 m is valid for long-term outcomes or whether it differs among trials using background therapy or lacking placebo controls entirely.
PMCID: PMC4237273  PMID: 22696079
hypertension; pulmonary; meta-analysis; statistics; trials
6.  Pulmonary Vascular Complications of Liver Disease 
Hepatopulmonary syndrome and portopulmonary hypertension are two pulmonary vascular complications of liver disease. The pathophysiology underlying each disorder is distinct, but patients with either condition may be limited by dyspnea. A careful evaluation of concomitant symptoms, the physical examination, pulmonary function testing and arterial blood gas analysis, and echocardiographic, imaging, and hemodynamic studies is crucial to establishing (and distinguishing) these diagnoses. Our understanding of the pathobiology, natural history, and treatment of these disorders has advanced considerably over the past decade; however, the presence of either still increases the risk of morbidity and mortality in patients with underlying liver disease. There is no effective medical treatment for hepatopulmonary syndrome. Although liver transplantation can resolve hepatopulmonary syndrome, there appears to be worse survival even with transplantation. Liver transplantation poses a very high risk of death in those with significant portopulmonary hypertension, where targeted medical therapies may improve functional status and allow successful transplantation in a small number of select patients.
PMCID: PMC3570657  PMID: 23155142
hepatopulmonary syndrome; hypertension; pulmonary; liver cirrhosis; pulmonary circulation
8.  Right Ventricular Structure is Associated with the Risk of Heart Failure and Cardiovascular Death: The MESA-Right Ventricle Study 
Circulation  2012;126(14):1681-1688.
Changes in right ventricular (RV) morphology are associated with morbidity and mortality in heart and lung disease. We examined the association of abnormal RV structure and function with the risk of heart failure (HF) or cardiovascular death in a population-based multiethnic sample free of clinical cardiovascular disease at baseline.
Methods and Results
The Multi-Ethnic Study of Atherosclerosis (MESA) performed cardiac magnetic resonance imaging (MRI) on 5098 participants between 2000–2002 with follow-up for incident heart failure and cardiovascular death (“death”) until January 2008. RV volumes and mass were available for 4204 participants. The study sample (N = 4,144) was 61.4 ± 10.1 years old and 47.6 % male. The presence of RV hypertrophy (increased RV mass) was associated with a more than twice the risk of heart failure or death after adjustment for demographics, body mass index, education, C-reactive protein level, hypertension, and smoking status (HR = 2.52, 95%CI 1.55–4.10, p < 0.001) and a doubling of risk (or more) with left ventricular mass at the mean value or lower (p for interaction = 0.05).
RV hypertrophy was associated with the risk of heart failure or death in a multi-ethnic population free of clinical cardiovascular disease at baseline.
PMCID: PMC3532921  PMID: 22932258
right ventricle; pulmonary heart disease; magnetic resonance imaging; pulmonary hypertension; survival
9.  Intravenous Immunoglobulin for Hypogammaglobulinemia after Lung Transplantation: A Randomized Crossover Trial 
PLoS ONE  2014;9(8):e103908.
We aimed to determine the effects of treatment with intravenous immunoglobulin on bacterial infections in patients with hypogammaglobulinemia (HGG) after lung transplantation.
We performed a randomized, double-blind, placebo-controlled two-period crossover trial of immune globulin intravenous (IVIG), 10% Purified (Gamunex, Bayer, Elkhart, IN) monthly in eleven adults who had undergone lung transplantation more than three months previously. We randomized study participants to three doses of IVIG (or 0.1% albumin solution (placebo)) given four weeks apart followed by a twelve week washout and then three doses of placebo (or IVIG). The primary outcome was the number of bacterial infections within each treatment period.
IVIG had no effect on the number of bacterial infections during the treatment period (3 during IVIG and 1 during placebo; odds ratio 3.5, 95% confidence interval 0.4 to 27.6, p = 0.24). There were no effects on other infections, use of antibiotics, or lung function. IVIG significantly increased trough IgG levels at all time points (least square means, 765.3 mg/dl during IVIG and 486.3 mg/dl during placebo, p<0.001). Four serious adverse events (resulting in hospitalization) occurred during the treatment periods (3 during active treatment and 1 during the placebo period, p = 0.37). Chills, flushing, and nausea occurred during one infusion of IVIG.
Treatment with IVIG did not reduce the short-term risk of bacterial infection in patients with HGG after lung transplantation. The clinical efficacy of immunoglobulin supplementation in HGG related to lung transplantation over the long term or with recurrent infections is unknown.
Trial Registration NCT00115778
PMCID: PMC4121238  PMID: 25090414
10.  Erythropoietin upregulation in pulmonary arterial hypertension 
Pulmonary Circulation  2014;4(2):269-279.
The pathophysiologic alterations of patients with pulmonary arterial hypertension (PAH) are diverse. We aimed to determine novel pathogenic pathways from circulating proteins in patients with PAH. Multianalyte profiling (MAP) was used to measure 90 specifically selected antigens in the plasma of 113 PAH patients and 51 control patients. Erythropoietin (EPO) functional activity was assessed via in vitro pulmonary artery endothelial cell networking and smooth muscle cell proliferation assays. Fifty-eight patients had idiopathic PAH, whereas 55 had other forms of PAH; 5 had heritable PAH, 18 had connective tissue disease (15 with scleroderma and 3 with lupus erythematosis), 13 had portopulmonary hypertension, 6 had PAH associated with drugs or toxins, and 5 had congenital heart disease. The plasma-antigen profile of PAH revealed increased levels of several novel biomarkers, including EPO. Immune quantitative and histochemical studies revealed that EPO not only was significantly elevated in the plasma of PAH patients but also promoted pulmonary artery endothelial cell network formation and smooth muscle cell proliferation. MAP is a hypothesis-generating approach to identifying novel pathophysiologic pathways in PAH. EPO is upregulated in the circulation and lungs of patients with PAH and may affect endothelial and smooth muscle cell proliferation.
PMCID: PMC4070770  PMID: 25006446
pulmonary arterial hypertension; plasma proteomics; multianalyte profiling; erythropoietin
11.  Pulmonary Hyperinflation and Left Ventricular Mass 
Circulation  2013;127(14):1503-1511e6.
Left ventricular (LV) mass is an important predictor of heart failure and cardiovascular mortality, yet determinants of LV mass are incompletely understood. Pulmonary hyperinflation in chronic obstructive pulmonary disease (COPD) may contribute to changes in intrathoracic pressure that increase LV wall stress. We therefore hypothesized that residual lung volume in COPD would be associated with greater LV mass.
Methods and results
The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study recruited smokers aged 50–79 years who were free of clinical cardiovascular disease. LV mass was measured by cardiac magnetic resonance. Pulmonary function testing was performed according to guidelines. Regression models were used to adjust for age, sex, body size, blood pressure and other cardiac risk factors.
Among 119 MESA COPD Study participants, mean age was 69±6 years, 55% were male and 65% had COPD, mostly of mild or moderate severity. Mean LV mass was 128±34 grams. Residual lung volume was independently associated with greater LV mass (7.2 grams per standard deviation increase in residual volume; 95% CI 2.2 to 12; P=0.004), and was similar in magnitude to that of systolic blood pressure (7.6 grams per standard deviation increase in systolic blood pressure, 95% CI 4.3 to 11 grams; p<0.001). Similar results were observed for LV mass to end-diastolic volume ratio (p=0.02) and with hyperinflation measured as residual volume to total lung capacity ratio (P=0.009).
Pulmonary hyperinflation, as measured by residual lung volume or residual lung volume to total lung capacity ratio, is associated with greater LV mass.
PMCID: PMC4018203  PMID: 23493320
Left ventricular mass; hyperinflation; chronic obstructive pulmonary disease
12.  African American race, obesity, and blood product transfusion are risk factors for acute kidney injury in critically ill trauma patients 
Journal of critical care  2012;27(5):496-504.
Acute kidney injury (AKI) is a common source of morbidity after trauma. We sought to determine novel risk factors for AKI, by Acute Kidney Injury Network (AKIN) criteria, in critically ill trauma patients.
Materials and Methods
Prospective cohort study of 400 patients admitted to the ICU of a level one trauma center, followed for development of AKI over five days.
AKI developed in 147/400 (36.8%) patients. In multivariable regression analysis, independent risk factors for AKI included African American race (OR 1.86; 95% CI 1.08,3.18; p=0.024), body mass index ≥30 (OR 4.72 versus normal BMI, 95% CI 2.59, 8.61, p<0.001), diabetes mellitus (OR 3.26; 95% CI 1.30,8.20; p=0.012), abdominal Abbreviated Injury Scale score ≥4 (OR 3.78; 95% CI 1.79,7.96; p<0.001), and unmatched packed red blood cells administered during resuscitation (OR 1.13 per unit; 95% CI 1.04,1.23; p=0.004). AKIN stages 1, 2, and 3 were associated with hospital mortality rates of 9.8%, 13.7%, and 30.4%, respectively, compared with 3.8% for those without AKI (p<0.001).
AKI in critically ill trauma patients is associated with substantial mortality. The findings of African American race, obesity, and blood product administration as independent risk factors for AKI deserve further study to elucidate underlying mechanisms.
PMCID: PMC3472045  PMID: 22591570
acute kidney injury; trauma; critical illness; race; obesity; transfusion; epidemiology; risk factors
13.  Clinical Risk Factors for Primary Graft Dysfunction after Lung Transplantation 
Rationale: Primary graft dysfunction (PGD) is the main cause of early morbidity and mortality after lung transplantation. Previous studies have yielded conflicting results for PGD risk factors.
Objectives: We sought to identify donor, recipient, and perioperative risk factors for PGD.
Methods: We performed a 10-center prospective cohort study enrolled between March 2002 and December 2010 (the Lung Transplant Outcomes Group). The primary outcome was International Society for Heart and Lung Transplantation grade 3 PGD at 48 or 72 hours post-transplant. The association of potential risk factors with PGD was analyzed using multivariable conditional logistic regression.
Measurements and Main Results: A total of 1,255 patients from 10 centers were enrolled; 211 subjects (16.8%) developed grade 3 PGD. In multivariable models, independent risk factors for PGD were any history of donor smoking (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.2–2.6; P = 0.002); FiO2 during allograft reperfusion (OR, 1.1 per 10% increase in FiO2; 95% CI, 1.0–1.2; P = 0.01); single lung transplant (OR, 2; 95% CI, 1.2–3.3; P = 0.008); use of cardiopulmonary bypass (OR, 3.4; 95% CI, 2.2–5.3; P < 0.001); overweight (OR, 1.8; 95% CI, 1.2–2.7; P = 0.01) and obese (OR, 2.3; 95% CI, 1.3–3.9; P = 0.004) recipient body mass index; preoperative sarcoidosis (OR, 2.5; 95% CI, 1.1–5.6; P = 0.03) or pulmonary arterial hypertension (OR, 3.5; 95% CI, 1.6–7.7; P = 0.002); and mean pulmonary artery pressure (OR, 1.3 per 10 mm Hg increase; 95% CI, 1.1–1.5; P < 0.001). PGD was significantly associated with 90-day (relative risk, 4.8; absolute risk increase, 18%; P < 0.001) and 1-year (relative risk, 3; absolute risk increase, 23%; P < 0.001) mortality.
Conclusions: We identified grade 3 PGD risk factors, several of which are potentially modifiable and should be prioritized for future research aimed at preventative strategies.
Clinical trial registered with (NCT 00552357).
PMCID: PMC3733407  PMID: 23306540
lung transplantation; clinical risk factors; primary graft dysfunction
14.  A Randomized Clinical Trial of Aspirin and Simvastatin for Pulmonary Arterial Hypertension: ASA-STAT 
Circulation  2011;123(25):2985-2993.
Pulmonary arterial hypertension (PAH) is a progressive disease which causes exercise limitation, heart failure, and death. We aimed to determine the safety and efficacy of aspirin and simvastatin in PAH.
Methods and Results
We performed a randomized, double-blind, placebo-controlled 2 × 2 factorial clinical trial of aspirin and simvastatin in patients with PAH receiving background therapy at four centers. A total of 92 patients with PAH were to be randomized to aspirin 81 mg or matching placebo and simvastatin 40 mg or matching placebo. The primary outcome was six-minute walk distance (6MWD) at six months. Sixty-five subjects were randomized when the trial was terminated by the DSMB after an interim analysis showed futility in reaching the primary end point for simvastatin. After adjustment for baseline 6MWD, there was no significant difference in the 6MWD at six months between aspirin (n = 32) and placebo (n = 33) [placebo-corrected difference = −0.5 m (95%CI, −28.4 – 27.4 m), p = 0.97] or between simvastatin (n = 32) and placebo (n = 33) [placebo-corrected difference = −27.6 m (95%CI, −59.6 – 4.3 m), p = 0.09]. There tended to be more major bleeding episodes with aspirin compared to placebo (4 events vs. 1 event, respectively, p = 0.17).
Neither aspirin nor simvastatin had a significant effect on the 6MWD, although patients randomized to simvastatin tended to have a lower 6MWD at six months. These results do not support the routine treatment of patients with PAH with these medications.
PMCID: PMC3427737  PMID: 21593252
pulmonary hypertension; clinical trial; anti-platelet agents; endothelial dysfunction
15.  The renin-angiotensin system and right ventricular structure and function: The MESA-Right Ventricle Study 
Pulmonary Circulation  2012;2(3):379-386.
The pulmonary vasculature is an important site of renin-angiotensin metabolism. While angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (collectively AIABs) have a role in left ventricular (LV) disease, the impact of AIABs on right ventricular (RV) function is unknown. AIAB use was determined by medication inventory during the Multi-Ethnic Study of Atherosclerosis baseline examination. RV measures were obtained via cardiac magnetic resonance imaging. The relationship between AIAB use and RV measures was assessed using multivariable linear regression, stratified by race/ethnicity, and adjusted for multiple covariates. AIAB use was associated with lower RV mass (-0.7 g, 95% confidence interval [CI] -1.3 to -0.1, P=0.03) in African Americans (N=1012) after adjustment for multiple covariates including LV mass. Among Caucasians (N=1591), AIAB use was associated with larger RV end-diastolic volume (3.7 mL, 95% CI 0.7-6.8, P=0.02) after adjustment for LV volume. No significant associations were seen between AIAB use and other RV measures or in Hispanic or Chinese American participants. AIAB use was associated with RV morphology in a race-specific and LV-independent manner, suggesting the renin-angiotensin system may play a unique role in RV structure and function. The use of AIABs in those with RV dysfunction warrants further study.
PMCID: PMC3487307  PMID: 23130107
angiotensin-converting enzyme inhibitor; angiotensin II receptor blockers; right ventricle; epidemiology; renin-angiotensin system
16.  Lower Socioeconomic Status Is Associated with Worse Outcomes in Pulmonary Arterial Hypertension 
Rationale: Lower socioeconomic status (SES) confers a heightened risk of common cardiovascular and pulmonary diseases and increased mortality. The association of SES with outcomes in patients with pulmonary arterial hypertension (PAH) is less clear.
Objectives: To determine the association between SES and outcomes in patients with PAH.
Methods: We performed a prospective cohort study at a national referral center for patients with PAH in China. Two hundred sixty-two consecutive incident patients aged 18 to 65 years with a diagnosis of idiopathic PAH were recruited between January 2007 and June 2011 and followed up until November 2011. The primary endpoint was all-cause mortality. An SES score for each patient was derived from their educational level, annual household income, occupation, and medical reimbursement rate.
Measurements and Main Results: Patients with a lower SES had higher unadjusted mortality rates, with 3-year survival estimates of 50.1, 70.8, and 86.0% in increasing tertiles of SES (P for trend < 0.001). After adjustment for clinical features, hemodynamics, and type of PAH treatment, the hazard ratios for death were 2.98 (95% confidence interval, 1.51–5.89) in the lowest tertile of SES and 1.80 (95% confidence interval, 0.89–3.63) in the middle tertile of SES compared with the upper tertile (P for trend = 0.006).
Conclusions: A lower SES is strongly associated with a higher risk of death in idiopathic PAH. This association was independent of clinical characteristics, hemodynamics, and treatment. Addressing the health disparities associated with a lower SES may improve the outcomes of patients with PAH.
PMCID: PMC3603556  PMID: 23220911
pulmonary arterial hypertension; socioeconomic status; survival
17.  Sex and Race Differences in Right Ventricular Structure and Function: The MESA-Right Ventricle Study 
Circulation  2011;123(22):2542-2551.
Right ventricular (RV) morphology is an important predictor of outcomes in heart and lung disease, however determinants of RV anatomy have not been well-studied. We examined the demographic factors associated with RV morphology and function in a population-based multiethnic sample free of clinical cardiovascular disease.
Methods and Results
The Multi-Ethnic Study of Atherosclerosis (MESA) performed cardiac magnetic resonance imaging (MRI) on 5098 participants. RV volumes and mass were available for 4204 participants. Normative equations for RV parameters were derived using an allometric approach. The study sample (N = 4123) was 61.5 ± 10.1 years old and 47.5% male. Older age was associated with lower RV mass (~5% lower mass per decade) with larger age-related decrements in men than in women (p for interaction < 0.05). Older age was also associated with higher RV ejection fraction (RVEF), an association which differed between races/ethnicities (p for interaction ≤ 0.01). Overall, men had greater RV mass (~8%) and larger RV volumes than women, but had lower RVEF (4% in absolute terms) (p < 0.001). African Americans had lower RV mass than Caucasians (p ≤ 0.002), whereas Hispanics had higher RV mass (p ≤ 0.02). Using the derived normative equations, 7.3% (95%CI, 6.5–8.1%) met criteria for RV hypertrophy and 5.9% (95%CI, 5.2–6.6%) had RV dysfunction.
In conclusion, age, sex, and race are associated with significant differences in RV mass, RV volumes and RVEF, potentially explaining distinct responses of the RV to cardiopulmonary disease.
PMCID: PMC3111939  PMID: 21646505
right ventricle; pulmonary heart disease; magnetic resonance imaging; pulmonary hypertension
18.  Lung Retransplantation 
Clinics in chest medicine  2011;32(2):367-377.
Lung retransplantation comprises a small proportion of lung transplants performed throughout the world, but has become more frequent in recent years. The selection criteria for lung retransplantation are similar to those for initial lung transplant. Survival after lung retransplantation has improved over time, but still lags behind that of initial lung transplantation. These differences in outcome may be attributable to medical comorbidities. Lung retransplantation appears to be ethically justified, however the optimal approach to lung allocation for retransplantation needs to be defined.
PMCID: PMC3081645  PMID: 21511096
lung transplantation; retransplantation
19.  Rationale and design of a Phase II clinical trial of aspirin and simvastatin for the treatment of pulmonary arterial hypertension: ASA-STAT 
Contemporary clinical trials  2010;32(2):280-287.
Pulmonary arterial hypertension (PAH) is a progressive disease which causes exercise limitation, heart failure, and death. Aspirin and simvastatin are highly effective and safe therapies for other cardiovascular diseases characterized by platelet activation and endothelial dysfunction, but have not been formally studied in PAH.
ASA-STAT is a Phase II, randomized, double-blind, placebo-controlled 2 × 2 factorial clinical trial of aspirin and simvastatin in patients with PAH. A total of 92 subjects were to be randomized to aspirin or aspirin placebo and simvastatin or simvastatin placebo. The primary outcome is the distance walked in six minutes at six months after randomization. Secondary measures include brachial artery flow-mediated dilation, circulating biomarkers of platelet and endothelial function, functional class, quality-of-life, and time to clinical end points. The incidence of adverse events will be compared between treatment groups.
Screening and Enrollment
We screened a total of 712 individuals with PAH. Sixty-five subjects were enrolled when the trial was terminated for futility in reaching the primary end point for simvastatin.
This study aims to determine whether aspirin or simvastatin have beneficial biologic or clinical effects in patients with PAH. The safety and side effects of these commonly prescribed cardiovascular drugs will also be assessed.
PMCID: PMC3034822  PMID: 21146637
Pulmonary hypertension; Endothelial dysfunction; platelets; Clinical trial
20.  Sex Hormones Are Associated with Right Ventricular Structure and Function 
Rationale: Sex hormones have effects on the left ventricle, but hormonal influences on the right ventricle (RV) are unknown.
Objectives: We hypothesized that sex hormones would be associated with RV morphology in a large cohort free of cardiovascular disease.
Methods: Sex hormones were measured by immunoassay and RV ejection fraction (RVEF), stroke volume (RVSV), mass, end-diastolic volume, and end-systolic volume (RVESV) were measured by cardiac magnetic resonance imaging in 1,957 men and 1,738 postmenopausal women. The relationship between each hormone and RV parameter was assessed by multivariate linear regression.
Measurements and Main Results: Higher estradiol levels were associated with higher RVEF (β per 1 ln[nmol/L], 0.88; 95% confidence interval [CI], 0.32 to 1.43; P = 0.002) and lower RVESV (β per 1 ln[nmol/L], −0.87; 95% CI, −1.67 to −0.08; P = 0.03) in women using hormone therapy. In men, higher bioavailable testosterone levels were associated with higher RVSV (β per 1 ln[nmol/L], 1.97; 95% CI, 0.20 to 3.73; P = 0.03) and greater RV mass and volumes (P ≤ 0.01). Higher dehydroepiandrosterone levels were associated with higher RVSV (β per 1 ln[nmol/L], 1.37; 95% CI, 0.15 to 2.59; P = 0.03) and greater RV mass (β per 1 ln[nmol/L], 0.25; 95% CI, 0.00 to 0.49; P = 0.05) and volumes (P ≤ 0.001) in women.
Conclusions: Higher estradiol levels were associated with better RV systolic function in women using hormone therapy. Higher levels of androgens were associated with greater RV mass and volumes in both sexes.
PMCID: PMC3081282  PMID: 20889903
sex; sex hormones; right ventricle
21.  Physical Activity and Right Ventricular Structure and Function 
Rationale: Intense exercise in elite athletes is associated with increased left ventricular (LV) and right ventricular (RV) mass and volumes. However, the effect of physical activity on the RV in an older community-based population is unknown.
Objectives: We studied the association between levels of physical activity in adults and RV mass and volumes.
Methods: The Multi-Ethnic Study of Atherosclerosis (MESA) performed cardiac magnetic resonance imaging on community-based participants without clinical cardiovascular disease. RV volumes were determined from manually contoured endocardial margins. RV mass was determined from the difference between epicardial and endocardial volumes multiplied by the specific gravity of myocardium. Metabolic equivalent–minutes/day were calculated from the self-reported frequency, duration, and intensity of physical activity.
Measurements and Main Results: The study sample (n = 1,867) was aged 61.8 ± 10 years, 48% male, 44% white, 27% African American, 20% Hispanic, and 9% Chinese. Higher levels of moderate and vigorous physical activity were linearly associated with higher RV mass (P = 0.02) after adjusting for demographics, anthropometrics, smoking, cholesterol, diabetes mellitus, hypertension, and LV mass. Higher levels of intentional exercise (physical activity done for the sole purpose of conditioning or fitness) were nonlinearly associated with RV mass independent of LV mass (P = 0.03). There were similar associations between higher levels of physical activity and larger RV volumes.
Conclusions: Higher levels of physical activity in adults were associated with greater RV mass independent of the associations with LV mass; similar results were found for RV volumes. Exercise-associated RV remodeling may have important clinical implications.
PMCID: PMC3056232  PMID: 20813888
exercise; pulmonary heart disease; pulmonary hypertension; magnetic resonance imaging
22.  Von Willebrand Factor and the Right Ventricle (The MESA-Right Ventricle Study) 
The American journal of cardiology  2012;110(12):1846-1851.
Elevation in plasma activity of von Willebrand Factor (vWF) reflects endothelial dysfunction and predicts death in pulmonary arterial hypertension (PAH). Higher vWF activity is also associated with lower right ventricular (RV) ejection fraction in PAH. Little is known about the relationship between vWF and RV structure and function in adults without cardiovascular disease. In the current investigation, we included 1,976 participants with MRI assessment of RV structure and function and measurement of vWF activity from the Multi-Ethnic Study of Atherosclerosis. Multivariable linear regression was used to estimate the associations between vWF activity and measures of RV structure and function after adjusting for demographics, anthropometrics, smoking, diabetes mellitus, hypertension and the corresponding left ventricular (LV) parameter. The average vWF activity was 140.7 ± 57.2%. Elevated vWF activity was independently associated with lower RV mass, RV end-diastolic volume and RV stroke volume in models with and without adjustment for the corresponding LV parameter (all p < 0.05). There was no association observed between vWF activity and RV ejection fraction. In conclusion, higher vWF activity is associated with lower RV mass, RV end-diastolic volume and RV stroke volume. These associations are independent of common cardiovascular risk factors and LV morphologic changes.
PMCID: PMC3696516  PMID: 22995970
Cardiovascular Imaging; Biomarkers; Pulmonary Hypertension; Right Ventricle
23.  Plasma Monocyte Chemotactic Protein-1 (MCP-1) Levels at 24 hours are a Biomarker of Primary Graft Dysfunction Following Lung Transplantation 
MCP-1, also known as CCL2, is a monocyte-attracting chemokine produced in lung epithelial cells. We previously reported an association of increased levels of plasma MCP-1 with primary graft dysfunction (PGD) after lung transplantation in a nested case control study of extreme phenotypes using a multiplex platform. In this study, we sought to evaluate the relationship between plasma MCP-1 levels as a biomarker across the full spectrum of PGD. We performed a prospective cohort study of 108 lung transplant recipients within the Lung Transplant Outcomes Group cohort. Plasma MCP-1 levels were measured pre-transplantation, 6 and 24 hours after transplantation. The primary outcome was development of grade 3 PGD within 72 hours of transplant, with secondary analyses at the 72- hour timepoint. Multivariable logistic regression was used to evaluate confounding. 30 subjects (28%) developed PGD. Median MCP-1 measured at 24 hours post transplant was elevated in subjects with PGD (167.95 vs. 103.5 pg/mL p=0.04). MCP-1 levels at 24 hours were associated with increased odds of grade 3 PGD after lung transplantation (OR for each 100 pg/mL 1.24, 95% CI 1.00, 1.53), and with grade 3 PGD present at the 72-hour timepoint (OR for each 100 pg/mL 1.57, 95% CI 1.18, 2.08), independent of confounding variables in multivariable analyses. MCP-1 levels measured pre-operatively and 6 hours after transplant were not significantly associated with PGD. Persistent elevations in MCP-1 levels at 24 hours are a biomarker of grade 3 PGD post-transplantation. Monocyte chemotaxis may play a role in the pathogenesis of PGD.
PMCID: PMC3500407  PMID: 22989614
Primary Graft Dysfunction; Lung transplantation; Monocyte Chemotactic Protein-1; Acute Lung Injury; Biomarker
24.  Matrix metalloproteinase-9 and plasminogen activator inhibitor-1 are associated with right ventricular structure and function: The MESA-RV Study 
Elevated resistance and reduced compliance of the pulmonary vasculature increase right ventricular (RV) afterload. Local and systemic inflammation and haemostatic abnormalities are prominent in pulmonary vascular diseases. We hypothesized that plasma biomarker levels indicating greater inflammation and coagulability associated with pulmonary vascular disease would be associated with RV structure and function measured by cardiac magnetic resonance imaging (MRI). The Multi-Ethnic Study of Atherosclerosis (MESA) performed cardiac MRI among participants aged 45–84 years without clinical cardiovascular disease. We assessed the associations of RV mass, RV end-diastolic volume (RVEDV), RV stroke volume (RVSV) and RV ejection fraction (RVEF) with plasma measures of inflammation (matrix metalloproteinase (MMP)-3 and -9, intercellular adhesion molecule (ICAM)-1, tumour necrosis factor receptor (TNF-R1), and E-selectin) and thrombosis (plasminogen activator inhibitor (PAI)-1, tissue factor, tissue factor pathway inhibitor and CD40 ligand).The study sample included 731 subjects. Higher MMP-9 levels were associated with lower RV mass before and after adjustment for left ventricular (LV) mass (p = 0.008 and p = 0.044, respectively). Higher levels of MMP-9 and PAI-1 were also associated with smaller RVEDV (p<0.05). Higher PAI-1 levels were associated with lower RVEF even after adjustment for LV ejection fraction (p = 0.017). In conclusion, MMP-9 and PAI-1 are associated with changes in RV structure and function which could be potentially related to a subclinical increase in pulmonary vascular resistance.
PMCID: PMC3045574  PMID: 20923324
Inflammation; thrombosis; hypertension; pulmonary
25.  Surrogate End Points in Pulmonary Arterial Hypertension: Assessing the Response to Therapy 
Clinics in chest medicine  2007;28(1):75-viii.
Pulmonary arterial hypertension (PAH) is a rare disease which is characterized by increased pulmonary vascular resistance and right heart failure. Recent discoveries in disease pathophysiology have been translated into effective therapies tested in clinical trials. The studies which have led to the regulatory board approval of therapies for PAH have focused on surrogate and intermediate end points, thought to reflect quantity and quality of life, respectively. However, validation of many of these surrogates is incomplete. It is also unknown which indicators of function or long-term survival should be used to formulate decisions regarding addition, discontinuation, or combination of therapies. Identification of suitable end points would therefore not only help investigators design appropriate clinical trials, but also assist clinicians in caring for patients with PAH. Hemodynamic, cardiac imaging, plasma biomarkers, and exercise testing hold some promise as potential surrogate end points for PAH. Functional status and quality of life assessments may also have important roles. Future studies should validate the most promising surrogate markers, so that patients, clinicians, subjects, and investigators may benefit from the advantages they confer on clinical care and on clinical trials.
PMCID: PMC1868503  PMID: 17338929

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