Coronary calcium detected by ultrafast computed tomography (CT) has been shown to be a marker of coronary artery disease in heart transplant recipients. The objective of this study was to examine the possible determinants of coronary calcium after heart transplantation. Over a 15-month period, 102 consecutive cardiac transplant recipients (mean age 53 years, 88 men) underwent ultrafast CT scanning of the heart, in addition to coronary angiography, to determine coronary calcium score on their annual follow-up (a median of 4.6 years [range 63 days to 9.1 years] after transplant). The following data were also recorded: the recipient's sex and date of birth, date of transplantation, date of ultrafast computed tomography and coronary angiography; recipient pretransplant diagnosis, history of diabetes mellitus and systemic hypertension, fasting lipid profile, immunosuppression, number of rejection episodes, and donor organ ischemic time. Forty six patients (45.1%) had total calcium scores >0 and 41 (40.2%) had at least 1 major coronary with angiographic narrowing >24%. On univariate analysis, coronary calcium was significantly associated with dyslipoproteinemia, total cholesterol was >6.0 mmol/L (240 mg/dl), triglycerides were >3.0 mmol/L (265 mg/dl), and lipoprotein(a) >30 mg/ dl; > or =25% angiographic disease was significantly associated with coronary calcium and dyslipoproteinemia. Logistic regression revealed that dyslipoproteinemia, systemic hypertension, and donor ischemic time were significant predictors of coronary calcium in transplanted hearts. We conclude that the prevalence of coronary calcium in heart transplant recipients is high and is related to recipient dyslipoproteinemia, systemic hypertension, and donor organ ischemic time.