LV function is generally assessed independent of structural remodeling and vice versa. The purpose of this study was to evaluate a novel LV global function index (LVGFI) that integrates LV structure with global function and to assess its predictive value for cardiovascular (CV) events throughout adult life in a multi-ethnic population of men and women without history of cardiovascular diseases at baseline. A total of 5004 participants in the Multi-Ethnic Study of Atherosclerosis underwent a cardiac magnetic resonance (CMR) study and were followed up for a median of 7.2 years. The LVGFI by CMR was defined by the ratio of stroke volume divided by LV total volume defined as the sum of mean LV cavity and myocardial volumes. Cox proportional hazard models were constructed to predict the end points of heart failure (HF), hard CV events and a combined endpoint of all CV events after adjustment for established risk factors, calcium score and biomarkers. A total of 579 (11.6%) incident events were observed during the follow-up period. In adjusted models, the end points of HF, hard CV events and all events were all significantly associated with LVGFI (HF, hazard ratio [HR]= 0.64, p<0.0001; hard CV events, HR=0.79, p=0.007; all events, HR=0.79, p<0.0001). LVGFI had a significant independent predictive value in the multivariable models for all CV event categories. The LVGFI was a powerful predictor of incident heart failure, hard CV events and a composite endpoint including all events in this multiethnic cohort.
left ventricle; ejection fraction; heart failure; LV mass; LV global function index
To determine the long term outcomes in children with severe aplastic anemia (SAA) treated with anti-thymocyte globulin (ATG) and cyclosporine (CsA), we conducted a retrospective analysis of the pediatric patients treated at our institution in all protocols that included horse ATG + CsA.
From 1989 to 2006, 406 patients, of whom about 20% were children under the age of 18, received an initial course of immunosuppressive therapy (IST) at our institution. Here we report the outcome of 77 children who were treated with a horse ATG + CsA based regimen during this time.
The overall response rate at 6 months was 74% (57/77); the cumulative incidence of relapse at 10 years was 33%, and the median time to relapse was 558 days. The cumulative incidence of evolution following IST was 8.5%; all 3 such events occurred among partial responders. Overall, there were 13 deaths (17%): four occurred within the 3 months following IST in patients who had a pre-treatment ANC of less than 100/uL, and nine deaths occurred more than 6 months after initiating IST. The median time to death was 570 days. The overall 10-year survival for the entire cohort was 80%; long term survival in children who responded to IST was 89%.
The long term survival in pediatrics patients who respond to IST is excellent, at about 90%. IST remains a good alternative in pediatric patients who lack an HLA-matched sibling donor and should be offered as initial therapy, prior to an alternative HSCT.
aplastic anemia; anti-thymocyte globulin; response; immunosuppression; pediatrics; survival
Subclinical cardiovascular disease is prevalent in patients with Metabolic
Syndrome (MetSyn). Left ventricular (LV) circumferential strain
(εCC) and longitudinal strain (εLL), assessed by
Speckle Tracking Echocardiography (STE), are indices of systolic function:
shortening is indicated by negative strain, and thus, the more negative the
strain, the better the LV systolic function. They have been used to
demonstrate subclinical ventricular dysfunction in several clinical
We hypothesized that MetSyn is associated with impaired myocardial function,
as assessed by STE.
We analyzed Multi-Ethnic Study of Atherosclerosis (MESA) participants who
underwent STE and were evaluated for all MetSyn components.
Among the 133 participants included [women: 63%; age: 65 ± 9 years (mean ±
SD)], the prevalence of MetSyn was 31% (41/133). Individuals with MetSyn had
lower εCC and lower εLL than those without MetSyn
(-16.3% ± 3.5% vs. -18.4% ± 3.7%, p < 0.01; and -12.1% ± 2.5% vs. -13.9%
± 2.3%, p < 0.01, respectively). The LV ejection fraction (LVEF) was
similar in both groups (p = 0.09). In multivariate analysis, MetSyn was
associated with less circumferential myocardial shortening as indicated by
less negative εCC (B = 2.1%, 95%CI:0.6 3.5, p < 0.01) even
after adjusting for age, ethnicity, LV mass, and LVEF). Likewise, presence
of MetSyn (B = 1.3%, 95%CI:0.3 2.2, p < 0.01) and LV mass (B = 0.02%, 95%
CI: 0.01-0.03, p = 0.02) were significantly associated with less
longitudinal myocardial shortening as indicated by less negative
εLL after adjustment for ethnicity, LVEF, and creatinine.
Left ventricular εCC and εLL, markers of subclinical
cardiovascular disease, are impaired in asymptomatic individuals with MetSyn
and no history of myocardial infarction, heart failure, and/or LVEF <
Atherosclerosis; Metabolic X Syndrome; Diabetes Mellitus / mortality; Ventricular Dysfunction / physiopathology; Ethnic Group
Using extreme phenotypes for association studies can improve statistical power. We study the impact of using samples with extremely high or low traits on the alternative model space, the genotype relative risks, and the genetic models in association studies. We prove the following results: when the risk allele causes high trait values, the more extreme the high traits, the larger the genotype relative risks, which is not always true for using extreme low traits; we also prove that a genetic model theoretically changes with more extreme trait except for the recessive or dominant models. Practically, however, the impact of deviations from the true genetic model at a functional locus due to selective sampling is virtually negligible. The implications of our findings are discussed. Numerical values are reported for illustrations.
Association studies; Extreme sampling; Genetic models; Genotype relative risks; Replication
The aim of the present study was to evaluate how torsion is influenced by left ventricular (LV) remodeling associated with age, gender and hypertension in a large community-based population.
Methods and Results
Myocardial shortening and torsion were assessed by tagged cardiac magnetic resonance (CMR) in 1478 participants without clinically apparent cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis (MESA). Torsion was defined as the difference between apical and basal rotation, divided by slice distance. In multivariable linear regression models, older age was associated with lower stroke volume (−3.6 ml/decade, p<0.001) and higher LV mass –to-volume ratio (0.03 g/ml/decade, p<0.001) along with lower circumferential shortening (−0.17%/decade, p<0.05). Torsion, however, was greater at older ages (0.14 °/decade, p<0.001) and in women (0.37°/cm vs. men, p<0.001). Hypertensive participants had higher LV mass and LV mass –to-volume ratio (15.5g and 0.07 g/ml, respectively, p<0.001 for both). Circumferential shortening was lower in hypertensive (−0.42%, p<0.01), whereas torsion was higher after adjustment for age and gender (0.17°/cm, p<0.05).
Older age is associated with lower LV volumes and greater relative wall thickness, and accompanied by lower circumferential myocardial shortening, whereas torsion is greater with older age. Hypertensive individuals have greater LV volumes and relative wall thickness and lower circumferential shortening. Torsion, however, is greater in hypertension independent of age and gender. Torsion may therefore represent a compensatory mechanism to maintain an adequate stroke volume and cardiac output in the face of progressively reduced LV volumes and myocardial shortening associated with hypertension and aging.
Torsion; Hypertension; Age; remodeling; Cardiac Magnetic Resonance
Stem cell transplantation (SCT) from a healthy donor can be curative for patients with hematologic malignancies resistant to other treatments. Elimination of malignant cells through a graft-versus-leukemia (GVL) effect involves donor T and natural killer (NK) cells, but their relative contribution to this process is poorly defined. NK cell alloreactivity and GVL effects are controlled by the nature of the interaction of NK activation receptors and killer-immunoglobulin-like-receptors (KIR) with major histocompatibility locus class I antigens on the target cell. We performed KIR-genotyping of HLA-identical sibling donors in 246 T cell-depleted SCTs to identify genetic factors affecting transplant outcome (treatment-related mortality [TRM], leukemic relapse, and survival). Univariate and multivariate analysis of transplant-related risk factors and KIR genotyping was performed to identify independent variables predictive of outcome for different forms of leukemia. Further to confirming known predictive factors for TRM and survival (CD34 cell dose, patient age, disease stage), statistical analysis revealed that 3 donor B haplotype KIR genes, 2DL5A, 2DSI, and 3DSI, were associated with significantly less relapse in patients with acute myelogenous leukemia (AML) (13% versus 57%) but not in patients with other myelogenous or lymphoid malignancies. AML patients receiving SCT from donors with these KIR genes relapsed 4 times less frequently than patients transplanted from donors with other KIR genotypes. These findings suggest specific, genetically determined, interactions between NK cells and AML cells that facilitate the GVL effect, and have implications for donor selection for AML patients.
NK cells; Stem cell transplantation; Activatory KIR; Relapse; Acute myelogenous leukemia
Systemic inflammation has been linked to the development of heart failure in population studies including MESA (Multi-Ethnic Study of Atherosclerosis) but little evidence exists regarding potential mechanism of this relationship. In this study, we used longitudinal MRI follow-up analysis to examine whether C-reactive protein (CRP) levels relate to progressive myocardial functional deterioration as a potential mechanism of incident heart failure.
Regional myocardial functional data from MESA participants who had baseline CRP measurement and also underwent tagged cardiac MRI both at baseline and at five-year follow-up were analyzed. Left ventricular (LV) midwall and mid-slice peak circumferential strain (Ecc), of which a more negative value denotes stronger regional myocardial function, was measured. Ecc change was calculated as the difference between baseline and follow-up Ecc.
During the follow-up period, participants (n=785) with elevated CRP experienced a decrease in strain, independent of age, gender and ethnicity (B=0.081; ΔEcc change per 1mg/L CRP change, 95% CI 0.036–0.126, p<0.001, Model 1), and additionally beyond systolic blood pressure, heart rate, diabetes, smoking status, body mass index, current medication and glomerular filtration rate (B=0.099, 0.052–0.145, p<0.001, Model 2). The relationship remained statistically significant after further adjustment for LV mass, coronary calcium score and interim clinical coronary events (B=0.098, 0.049–0.147, p<0.001, Model 3).
Higher CRP levels are related to progressive myocardial functional deterioration independent of subclinical atherosclerosis and clinical coronary events in asymptomatic individuals without previous history of heart disease.
inflammation; myocardial function; magnetic resonance imaging
Critically short telomeres produce apoptosis, cell senescence and chromosomal instability in tissue culture and animal models. Variations in telomere length have been reported in severe aplastic anemia (SAA) but their clinical significance is unknown.
To investigate the relationship between telomere length and clinical outcomes in SAA.
Design and Setting
Single institution analysis of SAA patients treated in sequential prospective protocols at NIH from 2000 to 2008.
We retrospectively analyzed pre-treatment leukocyte age-adjusted telomere length in 183 patients with SAA consecutively enrolled into immunosuppression protocols with anti-thymocyte globulin plus cyclosporine for correlation with clinical outcomes.
Main Outcomes Measures
The outcomes studied were hematologic response, relapse, clonal evolution and survival.
There was no relationship between hematologic response and telomere length with response rates of 56.5%, 54.3%, 60%, and 56.5% in the first (n=46), second (n=46), third (n=45), and fourth quartiles (n=46), respectively. In multivariate analysis, telomere length was associated with relapse, clonal evolution, and mortality. Evaluated as a continuous variable, telomere length inversely correlated with the probability of hematologic relapse (HR=0.16; 95% CI, 0.03–0.69; p=0.01). The rate of clonal evolution was higher in patients in the first quartile (24.5%; 95% CI, 8.7%–37.5%) compared to quartiles 2–4 (8.4%; 95% CI, 3.2%–13.3%; p=0.009), and evolution to monosomy 7 or complex cytogenetics was more common in the first quartile (18.8%; 95% CI, 3.5%–31.6%) compared to quartiles 2–4 (4.5%; 95% CI, 0.5%–8.2%; p=0.002). Survival between these two groups differed, with 66% (95% CI, 52.9%–82.5%) surviving 6 years in the first quartile compared to 83.8% (95% CI, 77.3%–90.9%) in quartiles 2–4 (p=0.008).
In a cohort of patients with severe aplastic anemia receiving immunosuppressive therapy, telomere length was unrelated to response, but was associated with risk of relapse, clonal evolution, and overall survival.
In severe acquired aplastic anemia, hematopoietic failure is the result of immune mediated destruction of bone marrow stem and progenitor cells. Immunosuppressive therapy with antithymocyte globulin (ATG) plus cyclosporine is an effective alternative to stem cell transplantation and improves blood counts and survival. While horse ATG is standard, rabbit ATG is more potent at depleting peripheral blood lymphocytes and is preferred in other clinical circumstances.
From December 2005 to July 2010, we performed a randomized trial comparing these two different ATG formulations at conventional regimens. Patients were treated at a single government facility. Primary outcome was hematologic response at 6 months, as determined by blood counts. The study was designed to accrue 60 patients per arm and powered to detect a 25% difference in response rate.
There was a large, unexpected difference in hematologic responses at 6 months in favor of horse ATG (68%; 95% confidence interval (CI), 56%–80%) compared to rabbit ATG (37%; 95% CI, 24%–49%; p<0.001). Overall survival at 3 years also differed, with 96% (95% CI, 90%–100%) surviving in the horse ATG group compared to 76% (95% CI, 61%–95%; p=0.04) in the rabbit ATG group when stem cell transplantation was censored, and 94% (95% CI, 88%–100%) for horse ATG and 70% (95% CI, 56%–86%; p=0.008) for rabbit ATG when stem cell transplantation events were not censored.
In a randomized study, rabbit ATG was markedly inferior to horse ATG as first treatment in severe aplastic anemia as measured by hematologic response and survival.
The aim of this study is to determine the test-retest reliability of the measurement of regional myocardial function by cardiovascular magnetic resonance (CMR) tagging using spatial modulation of magnetization.
Twenty-five participants underwent CMR tagging twice over 12 ± 7 days. To assess the role of slice orientation on strain measurement, two healthy volunteers had a first exam, followed by image acquisition repeated with slices rotated ±15 degrees out of true short axis, followed by a second exam in the true short axis plane. To assess the role of slice location, two healthy volunteers had whole heart tagging. The harmonic phase (HARP) method was used to analyze the tagged images. Peak midwall circumferential strain (Ecc), radial strain (Err), Lambda 1, Lambda 2, and Angle α were determined in basal, mid and apical slices. LV torsion, systolic and early diastolic circumferential strain and torsion rates were also determined.
LV Ecc and torsion had excellent intra-, interobserver, and inter-study intra-class correlation coefficients (ICC range, 0.7 to 0.9). Err, Lambda 1, Lambda 2 and angle had excellent intra- and interobserver ICC than inter-study ICC. Angle had least inter-study reproducibility. Torsion rates had superior intra-, interobserver, and inter-study reproducibility to strain rates. The measurements of LV Ecc were comparable in all three slices with different short axis orientations (standard deviation of mean Ecc was 0.09, 0.18 and 0.16 at basal, mid and apical slices, respectively). The mean difference in LV Ecc between slices was more pronounced in most of the basal slices compared to the rest of the heart.
Intraobserver and interobserver reproducibility of all strain and torsion parameters was excellent. Inter-study reproducibility of CMR tagging by SPAMM varied between different parameters as described in the results above and was superior for Ecc and LV torsion. The variation in LV Ecc measurement due to altered slice orientation is negligible compared to the variation due to slice location.
This trial is registered as NCT00005487 at National Heart, Lung and Blood institute.
CMR tagging; HARP; Test-retest reproducibility; SPAMM; Circumferential strain; Radial strain; Principal strains; Torsion
To define age-related geometric changes of the aortic arch and determine their relationship to central aortic stiffness and left ventricular remodeling.
The proximal aorta has been shown to thicken, enlarge in diameter and lengthen with aging in humans. However, no systematic study has described age-related longitudinal and transversal remodeling of the aortic arch and their relationship with left ventricular mass and remodeling.
We studied 100 subjects (55 women, 45 men, average age: 46±16 years) free of overt cardiovascular disease using magnetic resonance imaging to determine aortic arch geometry (length, diameters, height, width and curvature), aortic arch function (local aortic distensibility and arch pulse wave velocity PWV) and left ventricular volumes and mass. Radial tonometry was used to calculate central blood pressure.
Aortic diameters and arch length increased significantly with age. The ascending aorta increased most with age leading to aortic arch widening and decreased curvature. These geometric changes of the aortic arch were significantly related to decreased ascending aortic distensibility, increased aortic arch PWV (p<0.001) and to increased central blood pressures (p<0.001). Increased ascending aortic diameter, lengthening and decreased curvature of the aortic arch (unfolding) were all significantly associated with increased LV mass and concentric remodeling independently of age, gender, body size and central blood pressure (p<0.01).
Age-related unfolding of the aortic arch is related to increased proximal aortic stiffness in individuals without cardiovascular disease and associated with increased LV mass and mass-to-volume ratio independent of age, body size, central pressure and cardiovascular risk factors.
magnetic resonance imaging; aortic geometry; aging; elasticity; left ventricular remodeling
We investigate a change-point approach for modeling and estimating the regression effects caused by a concomitant intervention in a longitudinal study. Since a concomitant intervention is often introduced when a patient's health status exhibits undesirable trends, statistical models without properly incorporating the intervention and its starting time may lead to biased estimates of the intervention effects. We propose a shared parameter change-point model to evaluate the pre- and postintervention time trends of the response and develop a likelihood-based method for estimating the intervention effects and other parameters. Application and statistical properties of our method are demonstrated through a longitudinal clinical trial in depression and heart disease and a simulation study.
Change-point model; Concomitant intervention; Likelihood; Longitudinal study; Shared parameter model
Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired genetic disorder of the bone marrow that produces intravascular hemolysis, proclivity to venous thrombosis, and hematopoietic failure. Mutation in the PIG-A gene of a hematopoietic stem cell abrogates synthesis of glycosylphosphoinositol (GPI) anchors and expression of all GPI-anchored proteins on the surface of progeny erythrocytes, leukocytes, and platelets. Urokinase plasminogen activator receptor (uPAR), a GPI-linked protein expressed on neutrophils, mediates endogenous thrombolysis through a urokinase-dependent mechanism. Here we show that membrane GPI-anchored uPAR is decreased or absent on granulocytes and platelets of patients with PNH, while soluble uPAR (suPAR) levels are increased in patients’ plasma. Serum suPAR concentrations correlated with the number of GPI-negative neutrophils and were highest in patients who later develop thrombosis. In vitro, suPAR is released from PNH hematopoietic cells and from platelets upon activation, suggesting that these cells are the probable source of plasma suPAR in the absence of GPI anchor synthesis and trafficking of uPAR to the cell membrane. In vitro, the addition of recombinant suPAR results in a dose-dependent decrease in the activity of single-chain urokinase. We hypothesized that suPAR, prevents the interaction of urokinase with membrane-anchored uPAR on residual normal cells.
Survival in aplastic anemia has markedly improved in recent decades. In multivariate analysis, the introduction of newer antifungal agents and a decrease in fungal infections were independent predictors for survival in the months following immunosuppression among patients with persistent neutropenia.
Background. Persistent neutropenia associated with severe aplastic anemia (SAA) is an important risk factor for development of life-threatening infections. Earlier studies underscored the high mortality associated with invasive fungal infections (IFIs) in SAA. However, little is known about the current patterns of infections and the impact of advances in anti-infective therapy on survival in SAA.
Methods. We reviewed the records of 174 patients with SAA admitted to the Hematology Branch at NHLBI from 1989 to 2008 who were unresponsive to initial immunosuppressive therapy (IST) at 6 months. Three patient groups determined by IST protocol and time interval were compared: group 1 (43 patients; December 1989–October 1996), group 2 (51 patients; November 1996–October 2002), and group 3 (80 patients; November 2002–April 2008). Outcome variables included infections, patterns of resistance, survival, and infection-related mortality.
Results. During the past 2 decades, infection-related mortality decreased from 37% in group 1 to 11% in group 3 (P<.001), and the frequency of IFIs decreased from 49% in group 1 to 8% in group 3 (P<.001). Overall 5-year survival for all patients (n = 420) increased from 64% in group 1 to 79% in group 3 (P<.001). Among non-responders (n = 174), it increased from 23% in group 1 to 57% in group 3 (P<.001). In multivariate analysis, younger age, absolute neutrophil count >200 cells/μL before IST, absence of IFIs, and use of voriconazole were independently predictive of survival.
Conclusion. During the past 2 decades, there has been a significant decrease in IFIs, infection-related mortality, and overall mortality in patients with SAA unresponsive to initial IST.
Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis and progression to leukemia. Clinical and experimental evidence suggests an immune-mediated pathophysiology in some patients, in whom immunosuppressive therapy (IST) with horse antithymocyte globulin (h-ATG) and cyclosporine (CsA) can be effective. Because of the toxicities associated with h-ATG/CsA, we investigated an alternative regimen with alemtuzumab in MDS.
Patients and Methods
We conducted a nonrandomized, off-label, pilot, phase I/II study of alemtuzumab monotherapy in patients with MDS who were judged likely to respond to IST based on the following criteria: HLA-DR15–negative patients whose age plus the number of months of RBC transfusion dependence (RCTD) was less than 58; and HLA-DR15–positive patients whose age plus RCTD was less than 72. In total, 121 patients with MDS were screened, of whom 32 met eligibility criteria to receive alemtuzumab 10 mg/d intravenously for 10 days. Primary end points were hematologic responses at 3, 6, and 12 months after alemtuzumab.
Seventeen (77%) of 22 evaluable intermediate-1 patients and four (57%) of seven evaluable intermediate-2 patients responded to treatment with a median time to response of 3 months. Four of seven evaluable responders with cytogenetic abnormalities before treatment had normal cytogenetics by 1 year after treatment. Five (56%) of nine responding patients evaluable at 12 months had normal blood counts, and seven (78%) of nine patients were transfusion independent.
Alemtuzumab is safe and active in MDS and may be an attractive alternative to ATG in selected patients likely to respond to IST.
The metabolic phenotype of the failing heart includes a decrease in phosphocreatine and total creatine concentration [Cr], potentially contributing to contractile dysfunction. Surprisingly, in 32 week old mice over-expressing the myocardial creatine transporter (CrT-OE), we previously demonstrated that elevated [Cr] correlates with left ventricular (LV) hypertrophy and failure. The aim of this study was to determine the temporal relationship between elevated [Cr] and the onset of cardiac dysfunction and to screen for potential molecular mechanisms. CrT-OE mice were compared with wild-type (WT) littermate controls longitudinally using cine-MRI to measure cardiac function and single-voxel 1H-MRS to measure [Cr] in vivo at 6, 16, 32, and 52 weeks of age. CrT-OE mice had elevated [Cr] at 6 weeks (mean 1.9-fold), which remained constant throughout life. Despite this increased [Cr], LV dysfunction was not apparent until 16 weeks and became more pronounced with age. Additionally, LV tissue from 12 to 14 week old CrT-OE mice was compared to WT using 2D difference in-gel electrophoresis (DIGE). These analyses detected a majority of the heart’s metabolic enzymes and identified 7 proteins that were differentially expressed between groups. The most pronounced protein changes were related to energy metabolism: α- and β-enolase were selectively decreased (p<0.05), while the remaining enzymes of glycolysis were unchanged. Consistent with a decrease in enolase content, its activity was significantly lower in CrT-OE hearts (in WT, 0.59±0.02 μmol ATP produced/μg protein/min; CrT-OE, 0.31±0.06; p<0.01). Additionally, anaerobic lactate production was decreased in CrT-OE mice (in WT, 102±3 μmol/g wet myocardium; CrT-OE, 78±13; p=0.02), consistent with decreased glycolytic capacity. Finally, we found that enolase may be regulated by increased expression of the β-enolase repressor transcription factor, which was significantly increased in CrT-OE hearts. This study demonstrates that chronically increased myocardial [Cr] in the CrT-OE model leads to the development of progressive hypertrophy and heart failure, which may be mediated by a compromise in glycolytic capacity at the level of enolase.
Myocardial energy metabolism; heart failure; hypertrophy; creatine content; magnetic resonance imaging; magnetic resonance spectroscopy; proteomics
Arterial stiffness predicts cardiovascular events beyond traditional risk factors. However, the relationship with aging of novel noninvasive measures of aortic function by MRI and their interrelationship with established markers of vascular stiffness remain unclear and currently limit their potential impact. Our aim was to compare age-related changes of central measures of aortic function with carotid distensibility, global carotid–femoral pulse wave velocity, and wave reflections. We determined aortic strain, distensibility, and aortic arch pulse wave velocity by MRI, carotid distensibility by ultrasound, and carotid–femoral pulse wave velocity by tonometry in 111 asymptomatic subjects (54 men, age range: 20 to 84 years). Central pressures were used to calculate aortic distensibility. Peripheral and central pulse pressure, augmentation index, and carotid–femoral pulse wave velocity increased with age, but aortic strain and aortic arch PWV were most closely and specifically related to aging. Ascending aortic (AA) strain and distensibility decreased, respectively, by 5.3±0.5% (R2 = 0.54, P<0.0001) and 13.6±1 kPa−1×10−3 (R2=0.62, P<0.0001), and aortic arch pulse wave velocity increased by 1.6±0.13 m/sec (R2=0.60, P<0.0001) for each decade of age after adjustment for gender, body size, and heart rate. We demonstrate in this study a dramatic decrease in AA distensibility before the fifth decade of life in individuals with diverse prevalence of risk factors free of overt cardiovascular disease. In particular, compared with other measures of aortic function, the best markers of subclinical large artery stiffening, were AA distensibility in younger and aortic arch pulse wave velocity in older individuals.
MRI; aorta; aging; elasticity; pulse wave velocity
The relationship of changes in weight to outcomes in patients post myocardial infarction (MI) is controversial.
From the Enhancing Recovery in Coronary Heart Disease patients (ENRICHD) trial data, we assessed weight change, and the associations of baseline weight and change at follow-up outcomes and interactions between psychosocial factors.
At baseline 73.6% of patients (N=1706) were overweight or obese; 134 patients had BMI ≥ 40. Underweight patients were more likely to die or suffer nonfatal recurrent MI. After controlling for covariates, overweight and obese patients had similar outcomes to normal weight patients.
Eighteen percent of patients gained > 5%, 27% lost > 5% and 55% had < 5% change in weight. Compared with weight loss <5%, the risk of death (adjusted hazard ratio [HR] =1.74, p=0.01), and cardiovascular death (HR=1.79, p=0.04) were increased with weight loss > 5%. After propensity matching, weight loss >5% remained as a significant risk factor for death and CV death. There was no interaction between weight change and depression and/or social support at baseline or follow up. Weight change was not associated with recurrent MI or cardiovascular hospitalizations.
A large proportion of patients lose or gain >5% of body weight after an MI. The association between obesity and lower mortality is modulated by comorbidities. Weight loss after MI is associated with worse outcomes and is not related to depression or social support.
The goal of this analysis is to compare different test strategies for genetic association in case-control studies using related individuals. The first test is the trend test that is corrected for related individuals on the basis of identity-by-descent information. The second approach is to use generalized estimating equations to adjust for the correlation between relatives, and the third is the multiple outputation method. We compare the power of these test strategies in a simulation study, and apply these methods to a candidate gene dataset of Genetic Analysis Workshop 15 from the North American Rheumatoid Arthritis Consortium.
We propose a statistical method that includes the use of longitudinal regression models and estimation procedures for adjusting for covariate effects in applying the Haseman-Elston (HE) method for linkage analysis. Our methodology, which uses the covariate adjusted trait, contains three steps: a) modelling the covariate-adjusted population means of quantitative traits through regression; b) estimating the value of covariate-adjusted quantitative traits; and c) evaluating the linkage between the adjusted trait values and the markers based on alleles shared identically by descent.
We applied our adjusted HE method and the standard HE method in S.A.G.E. to the sib-pair subset of the Framingham Heart Study distributed by Genetic Analysis Workshop 13 with systolic blood pressure as the quantitative trait. Both methods gave similar patterns for the LOD scores, and exhibited highest multipoint LOD scores near location 70 cM of chromosome 12.
The adjusted HE method has two major advantages over the standard HE method used in S.A.G.E.: a) it has the capability to handle longitudinal data; b) it provides a more natural approach for adjusting the repeatedly measured covariates from each subject.