Concentric left ventricular remodeling and aortic stiffness: A comparison of obesity and hypertension

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Obese Subjects Show Sex-Specific Differences in Right Ventricular Hypertrophy

As right ventricular (RV) remodeling in obesity remains underinvestigated, and the impact of left ventricular (LV) diastolic dysfunction on RV hypertrophy is unknown, we aimed to investigate whether (1) sex-specific patterns of RV remodeling exist in obesity and (2) LV diastolic dysfunction in obesity is related to RV hypertrophy.Seven hundred thirty-nine subjects (women, n=345; men, n=394) without identifiable cardiovascular risk factors (body mass index [BMI], 15.3-59.2 kg/m2) underwent cardiovascular magnetic resonance (1.5 T) to measure RV mass (g), RV end-diastolic volume (mL), RV mass/volume ratio, and LV diastolic peak filling rate (mL/s). All subjects were normotensive (average, 119±11/73±8 mm Hg), normoglycaemic (4.8±0.5 mmol/L), and normocholesterolaemic (4.8±0.9 mmol/L) at the time of scanning. Across both sexes, there was a moderately strong positive correlation between BMI and RV mass (men, +0.8 g per BMI point increase; women, +1.0 g per BMI point increase; both P<0.001). Whereas women exhibited RV cavity dilatation (RV end-diastolic volume, +1.0 mL per BMI point increase; P<0.001), BMI was not correlated with RV end-diastolic volume in men (R=0.04; P=0.51). Concentric RV remodeling was present in both sexes, with RV mass/volume ratio being positively correlated to BMI (men, R=0.41; women, R=0.51; both P<0.001). Irrespective of sex, the LV peak filling rate was negatively correlated with both RV mass (men, R=-0.43; women, R=-0.44; both P<0.001) and RV mass/volume ratio (men, R=-0.37; women, R=-0.35; both P<0.001).A sex difference in RV remodeling exists in obesity. Whereas men exhibit concentric RV remodeling, women exhibit a mixed pattern of eccentric and concentric remodeling. Regardless of sex, reduced LV diastolic function is associated with concentric RV remodeling

Alterations in vascular function in primary aldosteronism - a cardiovascular magnetic resonance imaging study

Introduction: Excess aldosterone is associated with increased cardiovascular risk. Aldosterone has a permissive effect on vascular fibrosis. Cardiovascular magnetic resonance imaging (CMR) allows study of vascular function by measuring aortic distensibility. We compared aortic distensibility in primary aldosteronism (PA), essential hypertension (EH) and normal controls and explored the relationship between aortic distensibility and pulse wave velocity (PWV).<p></p> Methods: We studied PA (n=14) and EH (n=33) subjects and age-matched healthy controls (n=17) with CMR, including measurement of aortic distensibility, and measured PWV using applanation tonometry. At recruitment, PA and EH patients had similar blood pressure and left ventricular mass.<p></p> Results: Subjects with PA had significantly lower aortic distensibilty and higher PWV compared to EH and healthy controls. These changes were independent of other factors associated with reduced aortic distensibility, including aging. There was a significant relationship between increasing aortic stiffness and age in keeping with physical and vascular aging. As expected, aortic distensibility and PWV were closely correlated.<p></p> Conclusion: These results demonstrate that PA patients display increased arterial stiffness compared to EH, independent of vascular aging. The implication is that aldosterone invokes functional impairment of arterial function. The long-term implications of arterial stiffening in aldosterone excess require further study.<p></p&gt

Does patient satisfaction of general practice change over a decade?

Background The Patient Participation Program (PPP) was a patient satisfaction survey endorsed by the Royal Australian College of General Practitioners and designed to assist general practitioners in continuous quality improvement (CQI). The survey was been undertaken by 3500 practices and over a million patients between 1994 and 2003. This study aimed to use pooled patient questionnaire data to investigate changes in satisfaction with primary care over time. Methods The results of 10 years of the PPP surveys were analyzed with respect to 10 variables including the year of completion, patient age, gender, practice size, attendance at other doctors, and whether the practice had previously undertaken the survey. Comparisons were made using Logistic Generalized Estimating Equations (LGEE). Results There was a very high level of satisfaction with general practice in Australia (99% of respondents). An independent indicator of satisfaction was created by pooling the results of 12 questions. This new indicator had a greater variance than the single overall satisfaction question. Participants were shown to have higher levels of satisfaction if they were male, older, did not attend other practitioners or the practice was small in size. A minimal improvement in satisfaction was detected in this pooled indicator for the second or third survey undertaken by a practice. There was however no statistically significant change in pooled satisfaction with the year of survey. Conclusion The very high level of satisfaction made it difficult to demonstrate change. It is likely that this and the presentation of results made it difficult for GPs to use the survey to improve their practices. A more useful survey would be more sensitive to detect negative patient opinions and provide integrated feedback to GPs. At present, there are concerns about the usefulness of the PPP in continuous quality improvement in general practice.James Allan, Peter Schattner, Nigel Stocks and Emmae Ramsa

Does patient satisfaction of general practice change over a decade?

Background The Patient Participation Program (PPP) was a patient satisfaction survey endorsed by the Royal Australian College of General Practitioners and designed to assist general practitioners in continuous quality improvement (CQI). The survey was been undertaken by 3500 practices and over a million patients between 1994 and 2003. This study aimed to use pooled patient questionnaire data to investigate changes in satisfaction with primary care over time. Methods The results of 10 years of the PPP surveys were analyzed with respect to 10 variables including the year of completion, patient age, gender, practice size, attendance at other doctors, and whether the practice had previously undertaken the survey. Comparisons were made using Logistic Generalized Estimating Equations (LGEE). Results There was a very high level of satisfaction with general practice in Australia (99% of respondents). An independent indicator of satisfaction was created by pooling the results of 12 questions. This new indicator had a greater variance than the single overall satisfaction question. Participants were shown to have higher levels of satisfaction if they were male, older, did not attend other practitioners or the practice was small in size. A minimal improvement in satisfaction was detected in this pooled indicator for the second or third survey undertaken by a practice. There was however no statistically significant change in pooled satisfaction with the year of survey. Conclusion The very high level of satisfaction made it difficult to demonstrate change. It is likely that this and the presentation of results made it difficult for GPs to use the survey to improve their practices. A more useful survey would be more sensitive to detect negative patient opinions and provide integrated feedback to GPs. At present, there are concerns about the usefulness of the PPP in continuous quality improvement in general practice.James Allan, Peter Schattner, Nigel Stocks and Emmae Ramsa

A strategy to incorporate prior knowledge into correlation network cutoff selection

Correlation networks are frequently used to statistically extract biological interactions between omics markers. Network edge selection is typically based on the statistical significance of the correlation coefficients. This procedure, however, is not guaranteed to capture biological mechanisms. We here propose an alternative approach for network reconstruction: a cutoff selection algorithm that maximizes the overlap of the inferred network with available prior knowledge. We first evaluate the approach on IgG glycomics data, for which the biochemical pathway is known and well-characterized. Importantly, even in the case of incomplete or incorrect prior knowledge, the optimal network is close to the true optimum. We then demonstrate the generalizability of the approach with applications to untargeted metabolomics and transcriptomics data. For the transcriptomics case, we demonstrate that the optimized network is superior to statistical networks in systematically retrieving interactions that were not included in the biological reference used for optimization

The relationship between various measures of obesity and arterial stiffness in morbidly obese patients

<p>Abstract</p> <p>Background</p> <p>Obesity is associated with increased risk of cardiovascular disease. Arterial stiffness assessed by carotid femoral pulse wave velocity (PWV) is an independent predictor of cardiovascular morbidity and mortality. We aimed to investigate how various measures of body composition affect arterial stiffness.</p> <p>Methods</p> <p>This is an analysis of cross-sectional baseline data from a controlled clinical trial addressing changes in arterial stiffness after either surgery or lifestyle intervention in a population of morbidly obese patients. High-fidelity applanation tonometry (Millar^®, Sphygmocor^®) was used to measure pulse wave velocity (PWV). Carotid femoral PWV is a direct measure of arterial stiffness and is considered to be the gold standard method. The Inbody 720 Body Composition Analyzer was used for bioelectrical impedance analysis (BIA). Spearman's correlation, independent samples <it>t</it>-test, chi-square tests, Fisher's exact test and multiple linear regression analyses were used as statistical methods.</p> <p>Results</p> <p>A total of 133 patients (79 women), with a mean (SD) age of 43 (11) years were included in the study. Men had a significantly higher prevalence of obesity related comorbidities and significantly higher PWV, 9.1 (2.0) m/s vs. 8.1 (1.8) m/s, p = 0.003, than women. In the female group, PWV was positively correlated with WC, WHtR, BMI and visceral fat area. In the male group, PWV was negatively correlated with BMI. Multiple linear regression analysis showed that increasing BMI, WC, WHtR, visceral fat area and fat mass were independently associated with higher PWV in women, but not in men, after adjustment for age, hypertension and type 2 diabetes.</p> <p>Conclusion</p> <p>Most measures of general and abdominal obesity were predictors of arterial stiffness in female morbidly obese patients.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier <a href="http://www.clinicaltrials.gov/ct2/show/NCT00626964">NCT00626964</a></p

Adenosine stress CMR T1-mapping detects early microvascular dysfunction in patients with type 2 diabetes mellitus without obstructive coronary artery disease

Background Type 2 diabetes mellitus (T2DM) is associated with coronary microvascular dysfunction in the absence of obstructive coronary artery disease (CAD). Cardiovascular magnetic resonance (CMR) T1-mapping at rest and during adenosine stress can assess coronary vascular reactivity. We hypothesised that the non-contrast T1 response to vasodilator stress will be altered in patients with T2DM without CAD compared to controls due to coronary microvascular dysfunction. Methods Thirty-one patients with T2DM and sixteen matched healthy controls underwent CMR (3 T) for cine, rest and adenosine stress non-contrast T1-mapping (ShMOLLI), first-pass perfusion and late gadolinium enhancement (LGE) imaging. Significant CAD (>50% coronary luminal stenosis) was excluded in all patients by coronary computed tomographic angiography. Results All subjects had normal left ventricular (LV) ejection and LV mass index, with no LGE. Myocardial perfusion reserve index (MPRI) was lower in T2DM than in controls (1.60 ± 0.44 vs 2.01 ± 0.42; p = 0.008). There was no difference in rest native T1 values (p = 0.59). During adenosine stress, T1 values increased significantly in both T2DM patients (from 1196 ± 32 ms to 1244 ± 44 ms, p < 0.001) and controls (from 1194 ± 26 ms to 1273 ± 44 ms, p < 0.001). T2DM patients showed blunted relative stress non-contrast T1 response (T2DM: ΔT1 = 4.1 ± 2.9% vs. controls: ΔT1 = 6.6 ± 2.6%, p = 0.007) due to a blunted maximal T1 during adenosine stress (T2DM 1244 ± 44 ms vs. controls 1273 ± 44 ms, p = 0.045). Conclusions Patients with well controlled T2DM, even in the absence of arterial hypertension and significant CAD, exhibit blunted maximal non-contrast T1 response during adenosine vasodilatory stress, likely reflecting coronary microvascular dysfunction. Adenosine stress and rest T1 mapping can detect subclinical abnormalities of the coronary microvasculature, without the need for gadolinium contrast agents. CMR may identify early features of the diabetic heart phenotype and subclinical cardiac risk markers in patients with T2DM, providing an opportunity for early therapeutic intervention