Valor pronóstico de las calcificaciones coronarias, estudiadas mediante tomografía computarizada multicorte, en la población urémica

Resum

BACKGROUND: Patients with chronic kidney disease (CKD) have a high mortality, and cardiovascular disease is the leading cause of death. In these patients, coronary calcifications are more prevalent and extensives. OBJECTIVES: The main objetive is to analyse the predictive value of the presence of coronary calcifications detected by multi-detector spiral computed tomography (CT) in the ocurrence of cardiovascular events (CVE) and in the overall mortality in CKD patients, for a 2 years period. The main independent variable will be the coronary calcium score. The secondary objetives will be: to evaluate the prevalence and severity of coronary calcifications in CKD patients and to analyse the related factors with the development of these calcifications, in particular the expression of the transcription factor Cbfa-1. The independent variable will be the expression of this transcription factor in circulating nuclear cells. PATIENTS AND METHODS: The design of this project has 4 well-defined parts: The patient selection and the patient follow-up, the radiological studies, the analytic studies and the analysis of results. Patients with CKD stages 4 and 5 from Madrid and Guadalajara who comply with inclusion criteria will be included. RESULTS: 165 patients with CKD, stages 4 and 5, 111 in hemodialysis (HD) and 55 in predialysis (PD) were included. There was more males than females (90 ♂ and 76 ♀), diabetes prevalence was high (29 %), mean age was 64 ± 14 years and length of stay in HD was 27 (10 - 97) months. Follow-up time was 20 ± 8 months. Coronary calcium score (CCS) was 815 (152 - 1869) in HD and 255 (14 -855) in PD. CCS correlated with age (p < 0.001), tobacco (p 0.03), albumin (p < 0.001), triglycerides (p < 0.02) and CRP (p < 0.02). In the HD subgroup, BMI (r = 0.28, p 0.01) and diabetes (r = 0.66, p<0.009) also have a positive correlation with CCS, while in PD subgroup, cholesterol correlated too with CCS (p < 0.03). We measured Cbfa-1 content in circulating mononuclear cells in 88 patients in HD (0.64 ± 0.05) and in 12 patients in PD (0.59 ± 0.33). The Cbfa-1 in PD subgroup was associated with uric acid (r = 0.73, p 0.01), tobacco (r = 0.95, p 0.04) and CCS in left coronary artery (r = 0.67, p 0.01) and posterior descending coronary artery (r = 0.76, p 0.01). In HD subgroup, only highest levels of Cbfa-1 were associated with albumin (p < 0.009), length of stay on HD (p < 0.06) and CCS in circumflex coronary artery (p < 0.05) and right coronary artery (p < 0.04). During the follow-up period, CVE happened in 40 % and global mortality in 21 % (51% of this mortality could be attributed to CVE). The occurrence of cardiovascular mortality or CVE was associated with age (p <0.001), BMI (p < 0.03), previous CVE (p <0.001), diabetes (p <0.001), sedentary lifestyle (p< 0.001), albumin (p <0.001), CRP levels (p < 0.002), and total CCS (p <0.001). By Cox regression, CCS [HR 2.44 (1.39 – 4.28)] and CRP levels [HR 1.63 (0.97 – 2.75)] were independently associated with occurrence of cardiovascular mortality or CVE. CONCLUSIONS: Coronary calcifications are very prevalent in our population and CCS are very severe, especially in HD patients. Age, tobacco, diabetes, BMI, albumin, triglycerides and CRP levels seem to influence the coronary calcification process. Coronary artery calcification could influence the appearance of new CVE and cardiovascular mortality in these patients. However, it will be necessary to estimate if the analysis of these calcifications is a better marker of cardiovascular risk than other methods used to study vascular calcifications. We found a narrow correlation between Cbfa-1 and both CCS and uric acid levels in PD patients. Nevertheless, we do not know yet the real role of the circulating Cbfa-1 in the coronary calcification process.