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Myocardial calcification and cardiac dysfunction in chronic renal failure
S G Rostand1, C Sanders, K A Kirk
1Department of Medicine, University of Alabama, Birmingham 35294.
Insights
Increased myocardial calcium content in dialysis patients is linked to reduced left ventricular ejection fraction (LVEF). Poor calcium and phosphorus control, along with parathyroid hormone, may contribute to this cardiac dysfunction.
Area of Science:
- Cardiology
- Nephrology
- Radiology
Background:
- Myocardial calcium content is clinically relevant in end-stage renal disease (ESRD) but difficult to detect during life.
- Assessing myocardial calcium's impact on cardiac function in ESRD patients is crucial.
Purpose of the Study:
- To evaluate the relationship between myocardial calcium content and left ventricular ejection fraction (LVEF) in uremic patients undergoing dialysis.
Main Methods:
- Energy subtraction radiography measured myocardial calcium in dialysis patients, controls, and cardiomyopathy patients.
- Two-dimensional echocardiography assessed LVEF and left ventricular end-diastolic dimension.
- Laboratory tests included parathyroid hormone, calcium-phosphorus product, and other markers.
Main Results:
- Dialysis patients exhibited higher myocardial calcium content than controls.
- Elevated myocardial calcium correlated with lower LVEF and larger left ventricular end-diastolic dimension.
- Myocardial calcium content was associated with calcium-phosphorus product, vascular calcification, and race.
Conclusions:
- Increased myocardial calcium in dialysis patients may stem from poor mineral control and parathyroid hormone hyperactivity.
- Elevated myocardial calcium content is significantly associated with impaired myocardial function in ESRD patients.
Purpose:
Myocardial calcium content may have clinical importance in end-stage renal disease (ESRD), but it is difficult to detect during life. Our goal was to assess the effect of myocardial calcium content on left ventricular ejection fraction (LVEF) in uremic patients undergoing dialysis.
Patients And Methods:
Energy subtraction radiography of the chest was used to measure myocardial calcium content in 43 patients undergoing dialysis, in 32 control subjects, and in nine patients with advanced cardiomyopathy. LVEF and left ventricular end-diastolic dimension were measured by two-dimensional echocardiography. The concentration of parathyroid hormone was measured by radioimmunoassay; calcium-phosphorus product, alkaline phosphatase, and serum bicarbonate were also assessed.
Results:
Patients undergoing dialysis had a greater myocardial calcium content than control subjects [262 +/- 15.4 (mean +/- SE) versus 187 +/- 8 mg/cm2, p less than 0.05]. Ten patients with the highest myocardial calcium content (Group I) had the lowest LVEF values and highest left ventricular end-diastolic dimension. Significant inverse linear associations between LVEF and myocardial calcium content (r = -0.425, p = 0.013) and between parathyroid hormone concentration and LVEF (r = -0.352, p = 0.047) were noted. There was no association between parathyroid hormone concentration and myocardial calcium content. Stepwise regression analysis showed a strong positive correlation between myocardial calcium content and calcium-phosphorus product, vascular calcification, race (black), and parathyroidectomy. Similar analysis shows that LVEF was significantly associated with myocardial calcium content, lung calcium, calcium-phosphorus product, and race (black).
Conclusion:
We suggest that increased myocardial calcium content results from poor calcium and phosphorus control and may be enhanced by parathyroid hormone hyperactivity. Increased myocardial calcium content is strongly associated with myocardial dysfunction in patients undergoing dialysis.