Coronary artery calcifications predict long term cardiovascular events in non diabetic Caucasian hemodialysis patients.

Vascular calcifications are frequent in chronic renal disease and are associated to significant cardiovascular morbidity and mortality. The long term predictive value of coronary artery calcifications detected by multi­layer spiral computed tomography for major cardiovascular events was evaluated in non­diabetic Caucasian patients on maintenance hemodialysis free of clinical cardiovascular disease. Two­hundred and five patients on maintenance hemodialysis were enrolled into this observational, prospective cohort study. Patients underwent a single cardiac multi­layer spiral computed tomography. Calcium load was quantified and patients grouped according to the Agatston score: group 1 (Agatston score: 0), group 2 (Agatston score 1­400), group 3 (Agatston score 401­1000) and group 4 (Agatston score >1000). Follow­up was longer than seven years. Primary endpoint was death from a major cardiovascular event. Actuarial survival was calculated separately in the four groups with Kaplan­Meier method. Patients who died from causes other than cardiovascular disease and transplanted patients were censored. The "log rank" test was employed to compare survival curves. One­hundred two patients (49.7%) died for a major cardiovascular event during the follow­up period. Seven­year actuarial survival was more than 90% for groups 1 and 2, but failed to about 50% for group 3 and to <10% for group 4. Hence, Agatston score >400 predicts a significantly higher cardiovascular mortality compared with Agatston score <400 (p<0.0001); furthermore, serum Parathyroid hormone levels > 300 pg/l were associated to a lower survival (p < 0.05). Extended coronary artery calcifications detected by cardiac multi­layer spiral computed tomography, strongly predicted long term cardiovascular mortality in nondiabetic Caucasian patients on maintenance hemodialysis. Moreover, it was not related to conventional indices of atherosclerosis, but to other non­traditional risk factors, as serum Parathyroid hormone levels. A full cost­benefit analysis is however necessary to justify a widespread use of cardiac multi­layer spiral computed tomography in clinical practice.

An increased endothelial-independent vasodilation is the hallmark of the neurally mediated syncope.

BACKGROUND: The neurally mediated syncope (NMS) is sustained by complex cardiac and vascular reflexes, acting on and amplified by central autonomic loops, resulting in bradycardia and hypotension. HYPOTHESIS: Our aim was to assess whether the pathophysiology of NMS is also related to an abnormal peripheral vasoreactivity. METHODS: We evaluated by ultrasound the flow-mediated vasodilation (FMD) and the nitrate-mediated dilation (NMD) in 17 patients with NMS, induced by drug-free tilt test in 6 subjects and by nitrate-potentiated tilt test in the other 11 cases; the syncope was classified as vasodepressive (VD) in 8 cases, cardioinhibitory (CI) in 7, and mixed in 2. RESULTS: The FMD was not different from controls (10.2 ± 4.5 vs 11.4 ± 3.9, P = ns), with normal recovery times; the NMD was greater in fainting subjects than in controls (26.7 ± 7.3 vs 19.0 ± 3.6, P < 0.05), with higher values in VD than in CI syncope (31.1 ± 7.0 vs 23.1 ± 5.0, P = ns); compared to controls, subjects with NMS showed normal recovery times after FMD but longer recovery times after nitrate administration (13.0 ± 5.6 vs 6.3 ± 0.7 minutes, P < 0.05). CONCLUSIONS: The evaluation of endothelial function supports evidence that NMS is characterized by a marked and sustained endothelial-independent vasodilation, in the presence of a normal FMD; vascular hyperreactivity in response to nitrate administration is particularly overt in vasodepressive syncope and can explain the high rate of responses to nitrate administration during tilt test.