Coronary Artery Calcification Score in Recipients of Renal Transplant

San Diego—There is an association between coronary artery calcification and cardiovascular morbidity. Due to the heterogeneity in the population of kidney transplant recipients, there may be variation in the presence and severity of coronary artery calcification in those patients. Using baseline data from a clinical trial, Jennifer S. Lees, MBChB, MRCP, and colleagues in Scotland recently conducted an analysis to identify the factors associated with coronary artery calcification in a population of kidney transplant recipients. Results of the analysis were reported during a poster session at Kidney Week 2018 in a poster titled Factors Associated with Coronary Artery Calcification Score in Renal Transplant Recipients.

Recipients of a kidney transplant participating in a clinical trial of vitamin K supplementation (VIKTORIES: ISRCTN22012044) were included in the current analysis. Biochemical tests were conducted and demographic data were collected and recorded at the baseline visit. Non-contrast computed tomography coronary calcium (Agatston) score was used to determine coronary artery calcification; a score >160 was considered high. Factors associated with a high coronary artery calcification score were determined using binary logistic regression analysis. The analyses were conducted using stats and odds ratio (OR) for R statistical software.

The analysis included data on 68 trial participants. Of those, 70.6% were male, and 97.1% were white. Compared with patients with lower coronary artery calcification score, those with high coronary artery calcification score (58.8%; median score 1269) were older (60.8 years vs 54.7 years; P=.01) with similar systolic blood pressure (152 mmHg vs 144 mmHg; P=.08) and proteinuria (urine protein creatinine ratio 98 mg/mmol vs 72 mg/mmol; P=.56) ), but had longer time since renal transplant (11.2 years vs 7.4 years; P=.05) and time since initial renal replacement therapy (17.0 years vs 9.8 years; P=.002).

There was no difference between the two groups in graft function (glomerular filtration rate, 50.6 mL/min/1.73 m2 vs 54.2 mL/min/1.73 m2) and both groups had controlled calcium phosphate and parathyroid hormone. Both groups also commonly had vitamin D insufficiency (vitamin D <30 ng/nl) (71.4% vs 65.0%; P=.54). Results of binary logistic regression analysis demonstrated that factors associated with high coronary artery calcification score were older age (OR, 1.18 per 10-year increase; 95% confidence interval [CI], 1.05-1.33), longer duration of non-transplant renal replacement therapy (OR, 1.02 per year; 95% C I, 1.01-1.04), and current or previous smoking history (OR, 1.35; 95% CI, 1.09-1.67).

“In a diverse group of renal transplant recipients, high coronary artery calcification score was associated with older age, dialysis vintage, and smoking status, but not with traditional markers of chronic kidney disease mineral and bone disorder or vitamin D insufficiency. These offer few modifiable risk factors for intervention, though smoking cessation may be worthwhile. Activity of calcification inhibitors may be important in this patient group and warrant further study,” the researchers said.

Source: Lees JS, Rutherford E, Roditi G, Jardine AG, Mark PB. Factors associated with coronary artery calcification score in renal transplant recipients. Abstract of a poster (TH-PO131) presented at the American Society of Nephrology Kidney Week 2018, October 25, 2018, San Diego, California.