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Electron beam computed tomography in the evaluation of cardiac calcification in chronic dialysis patients
J Braun1, M Oldendorf, W Moshage
1Medical Clinic IV, Department of Nephrology, University of Erlangen-Nürnberg, Germany.
Insights
Dialysis patients show significantly higher coronary and valvular calcification, with rapid progression observed over one year. Hypertension is a key risk factor for this accelerated cardiac calcification.
Area of Science:
- Cardiology
- Nephrology
- Radiology
Background:
- Cardiovascular complications are a leading cause of mortality in patients with chronic kidney disease.
- Calcification of coronary arteries and heart valves is common in dialysis patients but its progression rate is not well understood.
Purpose of the Study:
- To evaluate electron beam computed tomography (EBCT) for detecting and quantifying cardiac calcifications in dialysis patients.
- To determine the progression rate of coronary and valvular calcifications in this population.
Main Methods:
- Compared 49 hemodialysis patients with 102 non-dialysis patients using EBCT and coronary angiography.
- Quantified coronary artery calcium score and assessed mitral/aortic valve calcification, with repeat measurements in dialysis patients after 12 months.
Main Results:
- Dialysis patients had 2.5- to 5-fold higher coronary artery calcium scores than non-dialysis patients.
- Hypertension, age, and aortic valvular calcification were associated with higher coronary calcium scores.
- Significant progression of calcification was observed in dialysis patients over one year.
Conclusions:
- EBCT is valuable for assessing cardiac calcification in dialysis patients.
- Dialysis patients exhibit severe and rapidly progressing coronary and valvular calcifications.
- Hypertension is a critical risk factor contributing to accelerated cardiac calcification in dialysis patients.
Abstract:
The purpose of this study was to assess the value of electron beam computed tomography in the detection of cardiac calcifications in coronaries and valves of dialysis patients and to determine the rate at which calcification progresses. Forty-nine chronic hemodialysis patients aged 28 to 74 years were compared with 102 non-dialysis patients aged 32 to 73 years with documented or suspected coronary artery disease, all of whom underwent coronary angiography. We used high-resolution electron beam computed tomography scanning to make 30 axial slices with a distance of 3 mm between each slice. The number of calcifications, the surface area, and the average and highest density values were measured. We calculated a quantitative coronary artery calcium score and assessed calcification of mitral and aortic valves. In dialysis patients, the measurements were repeated after 12 months. The coronary artery calcium score was from 2.5-fold to fivefold higher in the dialysis patients than in the non-dialysis patients. Hypertensive dialysis patients had higher calcium scores than non-hypertensive dialysis patients (P < 0.05). A stepwise, multiple regression analysis confirmed the importance of age and hypertension. No correlation between calcium, phosphate, or parathyroid hormone values and the coronary calcium score was identified; however, the calcium score was inversely correlated with bone mass in the dialysis patients (r = 0.47, P < 0.05). The mitral valve was calcified in 59% of dialysis patients, while the aortic valve was calcified in 55%. The coronary artery calcium score was correlated with aortic valvular, but not mitral valvular calcification. A repeat examination of the dialysis patients at an interval of 1 year showed a disturbing tendency for progression. Our data under-score the frequency and severity of coronary and valvular calcifications in dialysis patients, and illustrate the rapid progression of this calcification. Finally, they draw attention to hypertension as an important risk factor in this process.