Original investigations
Pathogenesis and treatment of kidney disease and hypertension
Coronary artery calcification in patients with CRF not undergoing dialysis

https://doi.org/10.1053/j.ajkd.2004.07.022Get rights and content

Background: Coronary artery calcification (CAC) correlates with the extent of coronary atherosclerosis and, consequently, with an increased risk for cardiovascular events. CAC is more frequent in uremic patients than in the general population. Nearly all data about CAC relate to patients on dialysis therapy. This study evaluates the prevalence and extent of CAC in patients with chronic renal failure (CRF) not yet on dialysis therapy. Methods: Consecutive outpatients with CRF not on dialysis therapy were enrolled and compared with controls (ie, healthy volunteers and patients with essential hypertension with normal renal function). Patients and controls were asymptomatic and had no previous history of myocardial infarction, coronary bypass surgery, or angioplasty. Patients with diabetes were excluded. Clinical characteristics, biochemical test results (included homocysteinemia and C-reactive protein level), and serum concentrations of calcium, phosphorus, and intact parathyroid hormone (iPTH) were evaluated in patients and controls. CACs were searched for and scored by means of spiral computed tomography (CT). To assess the CAC progression rate, spiral CT was repeated in some patients. Results: Eighty-five patients and 55 controls were studied. Patients were aged 52 ± 13 years and had a CRF duration of 6.3 ± 5.6 years, glomerular filtration rate of 33.0 ± 16.0 mL/min (0.55 ± 0.27 mL/s), serum calcium level of 9.5 ± 0.5 mg/dL (2.37 ± 0.12 mmol/L), serum phosphorus level of 4.1 ± 0.9 mg/dL (1.32 ± 0.29 mmol/L), and serum iPTH level of 143 ± 121 pg/mL (ng/L). CAC was found in 40% of patients and 13% of controls; calcification scores were 422 ± 634 in patients and 43.9 ± 33 in controls. Only age (P < 0.001) was a predictor of CAC. In patients with a repeated score performed (after a mean of 7.9 months), calcification scores increased (from 383 ± 627 to 682 ± 890) in 8 of 10 patients. Conclusion: CAC is already present in the early phase of CRF; the prevalence is greater in patients with CRF than in controls, but less than that reported in dialysis patients. Serum concentrations of calcium, phosphorus, iPTH, and inflammation markers do not predict the appearance or progression of CAC.

Section snippets

Methods

The protocol was approved by the local institutional review board.

Consecutive outpatients with a glomerular filtration rate (GFR) unchanged for at least 12 months before study entry were enrolled after they had given informed consent. Exclusion criteria were symptoms of heart failure or coronary artery disease; previous history of myocardial infarction, coronary bypass surgery, or angioplasty; and stroke, diabetes, rapidly progressive renal disease, or arrhythmia (that would exclude gating

Results

One hundred forty individuals were studied: 85 patients with CRF and 55 controls.

Clinical characteristics and biochemical variables are listed in Table 1. Patients and controls were well matched for clinical characteristics and biochemical variables, including values for serum calcium, phosphorus, and calcium-phosphorus product. Variables strictly linked to renal function, such as urea level, GFR, iPTH level, and homocysteine level, were significantly different in controls. Causes of renal

Discussion

CAC is common not only in patients who have been on dialysis therapy for years, but also in those who initiate dialysis treatment.2, 3, 4, 5, 15, 16 Recently, CAC was evaluated in patients with CRF not yet on dialysis therapy, but with documented coronary artery disease.17 The study focused on the effects of some antihypertensive drugs (ie, calcium channel blockers versus diuretics) on plaque progression, rather than on prevalence of CAC. To date, no data are available on the prevalence of CAC

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