Coronary Artery Calcification in Patients on Chronic Hemodialysis: Evaluation by Electron Beam Computed Tomography

Abstract

Abstract: In patients on chronic hemodialysis, the incidence of cardiovascular events and mortality rate are higher than those in the general population. These events are associated with coronary, aortic valve, or mitral valve calcification, and show a poor prognosis. However, no study has investigated coronary or cardiac valve calcification in patients on chronic hemodialysis and its prognosis. In this study, we performed electron beam computed tomography (EBCT) in 400 patients who underwent chronic hemodialysis at four dialysis units in Okinawa Prefecture, Japan, between 1996 and 2003, and measured the coronary artery calcification score (CACS), aortic valve calcification score (AVCS), and mitral valve calcification score (MVCS) to analyze the association of these parameters with the prognosis. In addition, we examined the effects of sevelamer hydrochloride, which reduces the serum phosphorus level, reducing CACS. We reached the following conclusions with respect to the following examination items: (i) Factors involved in an increase in CACS in patients undergoing dialysis: in these patients with a rapid increase in CACS, the serum triglyceride and LDL cholesterol levels were higher than the values in the control group; (ii) Cut‐off value of CACS influencing the outcome in patients on dialysis: we reviewed 104 chronic dialysis patients after EBCT was initiated. The group with a CACS of 200 or more showed a significantly poorer outcome compared to the group with a CACS of less than 200; (iii) Accuracy (sensitivity, specificity) of CACS screening on EBCT: we investigated the sensitivity and specificity of CACS based on the presence or absence of coronary artery disease on coronary angiography. The CACS values ranged from 100 to 3000, and their diagnostic accuracy was not satisfactory. Therefore, in patients without symptoms, EBCT may not be appropriate for coronary disease screening; (iv) Does sevelamer hydrochloride inhibit an increase in CACS by reducing the serum phosphorus level in patients on chronic hemodialysis?: in 98 patients on dialysis, this agent reduced the serum phosphorus level, and we examined whether it inhibits an increase in CACS. However, no significant results have been obtained due to a short follow‐up period; and (v) Correlations of CACS, AVCS, and MVCS with the outcome in patients on hemodialysis: AVCS was correlated with the outcome. Aortic valve calcification may markedly influence cardiac hemodynamics.