Predictive Value of Coronary Calcifications for Future Cardiac Events in Asymptomatic Patients with Severe Chronic Kidney Disease.

Abstract

Coronary calcification is a well-established risk factor for cardiovascular events. This retrospective study sought to determine the predictive value of coronary calcification in a specific group of patients with chronic kidney disease. We included 1094 asymptomatic patients (724 males, 370 females, age 62 ± 9.3 years) referred for cardiological examination. Patents were divided into two groups depending on their renal function. Coronary calcification was determined with a multi-slice computer tomography (CT) scanner. For quantification of coronary calcification the Agatston score was calculated. Over a mean follow up period of 6.2 ± 1.3 years we observed the rate of cardiovascular events (185 events, 61 myocardial infarctions, 103 revascularizations, 21 cardiac deaths). The calcium score was significantly higher in patients with severe kidney disease (glomerular filtration rate (GFR) ≤30 mL/min/1.72 m2) compared with those with normal to moderate reduced renal function (GFR ≥30 mL/min/1.72 m2) (207 ± 190 vs.121 ± 169, p ≤ 0.001). The event rate in patients with severe impaired renal function was significantly higher compared to patients with normal to moderate reduced renal function (20.6% vs. 14.8%, p = 0.0001). The hazard ratio for cardiovascular events increased constantly with the calcium score in both groups. The hazard ratio in patients with severe kidney disease was significantly lower compared to patients in corresponding groups with regular to moderate reduced renal function (7.3 vs. 9.3, p = 0.01). No cardiac events were observed in patients with a calcium score of 0. We could demonstrate that risk prediction with the calcium score is possible in patients with severe chronic kidney disease even if the calcium score overestimates the risk for future cardiovascular events compared to patients with normal to moderate reduced renal function.