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Echocardiographic assessment of systolic function in dialysis patients
1Area Renal Unit, Leicester General Hospital, UK.
Insights
Echocardiography for cardiac function in uremic patients is complex due to altered loading conditions during hemodialysis. Load-independent end-systolic indices may offer insights, but require validation in this patient group.
Area of Science:
- Nephrology
- Cardiology
- Medical Imaging
Background:
- Echocardiography is used to assess cardiac function in uremic patients.
- Altered loading conditions in uremia complicate cardiac function assessment, especially during hemodialysis.
- Traditional echocardiographic indices are sensitive to preload and afterload variations.
Purpose of the Study:
- To evaluate the reliability of echocardiographic indices for assessing cardiac function in uremic patients undergoing hemodialysis.
- To investigate the potential of load-independent end-systolic indices for assessing intrinsic cardiac contractility.
- To examine the influence of altered loading conditions on end-systolic indices in uremia.
Main Methods:
- Review of echocardiographic studies in uremic patients.
- Analysis of the impact of altered loading conditions (preload, afterload) on cardiac measurements.
- Examination of end-systolic indices and their relationship with loading conditions.
Main Results:
- Echocardiographic measurements of cardiac dimensions are significantly influenced by altered loading conditions in uremia.
- Assessment of cardiac function during hemodialysis is particularly challenging due to these influences.
- Evidence suggests end-systolic indices may not be load-independent in uremic patients without autonomic blockade.
Conclusions:
- Standard echocardiographic assessment of cardiac function in uremic patients is limited by loading condition variability.
- End-systolic indices, while promising for load-independent assessment, require further validation in uremic populations.
- More research is needed to confirm the utility of these indices in dialysis patients.
Abstract:
Echocardiography has been widely used to investigate cardiac function in uraemic patients. There is no doubt about the validity of this technique in certain situations, particularly the demonstration of structural abnormalities and pericardial effusions. However, the assessment of cardiac function by measurement of cardiac dimensions and their rate of change is complicated by the profound influence of altered loading conditions, common in uraemia, on the measurements obtained. This is a particular problem in the assessment of changes in cardiac function during haemodialysis. Even studies utilising isovolaemic dialysis are open to criticism, due to the effects of altered afterload on cardiac emptying. Recently the experimental finding that end-systolic volume is independent of end-diastolic volume and linearly related to afterload has raised the possibility that non-invasive assessment of end-systolic indices may allow load-independent assessment of intrinsic cardiac contractility in patients. However, none of the studies using these indices in uraemic patients has validated the assumption that they are indeed load-independent in this clinical situation. Evidence is presented suggesting that the end-systolic pressure:volume relationship is altered by the administration of a volume load and that manipulation of afterload without autonomic blockade results in markedly increased contractility, presumably due to reflex sympathetic activity. More work is required before these indices are used uncritically in dialysis patients.