Browsing by Author "Prakaschandra, Dorcas Rosaley."
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item The echocardiographic manifestations of an urban, working class community with a high cardiovascular risk profile.(2013) Prakaschandra, Dorcas Rosaley.; Naidoo, Datshana Prakesh.; Gordon, Michelle Lucille.The metabolic syndrome (MS), consequent upon the pandemic of obesity and diabetes, is associated with an increased risk for cardiovascular (CV) disease. Development of sub-clinical cardiac structural and functional changes associated with CV disease risk factors may be detected on echocardiography. The extent to which these structural changes and CV risk factors are dependent on genetic factors is not clearly established. This project was designed to investigate the relationship between CV disease risk factors, cardiac structural and functional changes and underlying genetic abnormalities. Specifically, the risk factor profile and the presence of the MS were determined. This was then correlated with the echocardiographic findings and gene polymorphisms. Method: A randomly selected cohort of 1428 subjects from the Phoenix community was studied. Demographic data was collected using the WHO STEPS instrument. Blood samples for biochemistry and genetic analysis, together with anthropometric measurements, were collected. Blood pressure and echocardiography was performed on all subjects. The metabolic syndrome was classified according to the National Cholesterol Education Panel (NECP) Adult Treatment Panel III (ATP III) and International Diabetes Federation (IDF) criteria. The Lipoprotein Lipase and Human Paraoxonase-1 genes were genotyped on a Light Cycler 480 Real-Time PCR instrument, using allele-specific probes and sequencing. Results: There was a high prevalence of CV risk factors in this sample; particularly increased waist circumference (79%), obesity (64%) insulin resistance (58%) and hypertension (50%) across the age groups. This translated into a high prevalence of MS (38% using NCEP ATPIII and 46% using IDF criteria). There were significant echocardiographic differences between subjects with and without MS for chamber dimensions (p<0.001), left ventricular wall thickness (p<0.001) and mass (p<0.001), diastolic indices (E-wave {p<0.001}, trans-mitral ratio {p=0.017}) and sub-epicardial adipose tissue (SEAT) thickness (p<0.001). Stepwise multivariate analysis identified age (95% CI 0.975; 0.998), gender (95%CI 0.48; 0.9) and hypertension (95% CI 0.53; 0.99) as independent risk factors for diastolic abnormalities. Logistic regression identified age as the most significant contributor to diastolic abnormalities (OR=1.02; 95%CI 1.009; 1.03; Wald=13.4), followed by the waist circumference (OR=1.025; 95%CI 1.014; 1.037) and BMI (OR=1.075; 95% CI 1.035; 1.117). Genetic analysis showed significant associations between the heterozygous variant of Q192R genotype (PON-1 gene) and elevated HDL levels and also between this variant and obese women (p= <0.05). Conclusion: The high prevalence of CV risk factors and MS in this community has reached epidemic proportions. Although the MS was associated with significant remodelling of cardiac structure, alteration of diastolic indices and increased sub-epicardial adipose tissue thickness, BMI and waist circumference were stronger promoters of altered cardiac physiology. This augurs poorly for this population group unless intervention is introduced to address the markedly high prevalence of these culprit drivers.Item Time-course changes in the echocardiographic parameters and NT-proBNP levels in patients with severe mitral regurgitation undergoing valve replacement.(2007) Prakaschandra, Dorcas Rosaley.; Naidoo, Datshana Prakesh.Conventional echocardiographic parameters are currently used in determining the timing for surgery in patients with mitral regurgitation. Since brain natriuretic peptide (BNP) rises in response to ventricular muscle stretch, and is to detect early heart failure, we hypothesized that BNP would be activated in patients with regurgitant valvular heart disease and concomitant left ventricular dilatation. Aim/Objectives: We therefore studied the pattern of changes in NT-pro BNP in patients with chronic severe rheumatic mitral regurgitation who were undergoing mitral valve replacement and compared this with the newer modality of tissue Doppler imaging (TDI). Setting: Patients submitted to surgery were prospectively evaluated over 8 months at Inkosi Albert Luthuli Central Hospital, Department of Cardiology. Controls were obtained from the outpatients' follow-up clinic. Methods: Simultaneous quantification of the severity of mitral regurgitation (MR), left ventricular (LV) end systolic volume (ESV), left atrial (LA) volume and Doppler filling ratios (mitral (E)/annulus (Ea)) were performed at baseline in all patients and was repeated at 1-week and at the six-week follow-up visit in surgical patients. Results: Both groups were similar for age and gender and echo-Doppler parameters in all patients preoperatively except LA size (p< 0.01) and volume (p<0.004) which were more elevated in the surgical group. Mean NT-pro BNP levels were markedly elevated preoperatively (262 pmolll) in all surgical cases compared to controls (57 pmol/l; p=0.0001). NT-pro BNP levels increased further at one week post surgery (395 pmol/l) and subsided at the six week follow-up visit (94 pmol/I). These changes were accompanied by significant reduction in LA (p= 0.003) and LV chamber dimensions (EDD = 0.004) with an increase in the ejection fraction from 42% at one week to 52 % at six weeks. Four patients had abnormally elevated NT-pro BNP levels (>53pmol/l) at the 6-week follow-up visit. A ROC curve was constructed for all variables to separate surgical cases from controls. The area under the curve was highest for NT-pro BNP (sensitivity= 96%, specificity 45 %). Conclusion: 1. There was a significant difference in the left atrial chamber size and volume, as well as Em/Ea (TDI) and NT-proBNP levels preoperatively between the two groups. The lack of a significant difference in the LV parameters between surgical and control groups suggest an almost total reliance on symptoms in deciding the timing of surgery which was reflected by markedly elevated NT-pro BNP in all surgical patients. 2. Postoperatively, there was a significant reduction in LA and LV dimensions. 3. The high false positivity rate for NT-pro BNP suggests that the test is most likely reflecting early LV decompensation in the less symptomatic control patients who rightly need surgery. 4. Tissue Doppler indices had similar sensitivity but low specificity compared to NT-proBNP. 5. Serial estimations of NT-pro BNP may prove useful in selecting patients for surgery.