| Popis: |
With the greater availability and success of dialysis and renal transplantation programmes, cardiovascular disease has emerged as the dominant threat to survival of patients with end-stage renal failure. The identification of left ventricular hypertrophy as an independent determinant of outcome in such patients prompted this investigation into factors which might influence left ventricular mass. Reports of regression of ventricular hypertrophy after renal transplantation suggested correction of uraemia, anaemia or hyperparathyroidism, either alone or in combination might be important. The aim of this thesis therefore was to examine the left ventricle by means of established echocardiographic techniques in dialysis patients in relation to different therapeutic interventions. Patients were studied before and after renal transplantation, treatment with recombinant human erythropoietin for anaemia, and surgical parathyroidectomy for hyperparathyroidism. Stable dialysis patients were also studied at intervals. Three hundred and seventy eight echocardiograms in 223 patients were performed and analysed by the author. A cross-sectional study of echocardiograms from dialysis patients revealed that men had greater left ventricular mass indices (LVMI) than women, after adjusting for body surface area. LVMI tended to increase with age, and was greatest in diseases associated with severe hypertension. Serial changes in LVMI followed no predictable pattern but correlated with changes in systolic blood pressure and haemoglobin. There were no differences between CAPD and haemodialysis subjects. Following renal transplantation, the expected decrease in LVMI was not observed. However LV dimensions did change in most patients. A search for factors which might be associated with these changes revealed that the most anaemic patients at the time of surgery had a greater reduction in end-diastolic dimension (EDD), while those with functioning arteriovenous fistulae had persisting elevation of EDD. Using multiple logistic regression analysis, systolic blood pressure and male sex were related to the pre-operative LVMI. Age at the start of dialysis treatment was the only covariate to be associated with outcome. Successful treatment of renal anaemia with erythropoietin was associated with a small reduction in LVMI and LV wall thickness. Parathyroidectomy in dialysis patients resulted in similar changes. Variability in response was a consistent feature in all of the study groups and led to further investigation of the influence of volume overload by assessing ventricular changes as a result of dialysis with fluid removal. Highly significant changes in all left ventricular diastolic dimensions were observed, indicating that the widely used method of determining LV mass is not suitable for serial assessment of dialysis patients who are subject to changes in fluid balance. |
