Heart rate variability in advanced chronic kidney disease with or without diabetes: midterm effects of the initiation of chronic haemodialysis therapy.

BACKGROUND: Previous studies in different clinical settings have established heart rate variability (HRV) as a significant independent risk factor for higher mortality and cardiac death. The aim of this study was to examine the effect of chronic haemodialysis therapy on time- and frequency-domain parameters of HRV in diabetic and non-diabetic patients with chronic kidney disease (CKD). METHODS: We studied 25 patients with stage 4 CKD and type 2 diabetes mellitus (CKD4+DM), 25 patients with stage 4 CKD without diabetes (CKD4), 25 patients with type 2 diabetes mellitus (DM) and 25 healthy subjects (HS). The study was performed in two phases. In the first phase, a 24-h Holter electrocardiographic (ECG) monitoring was performed in all subjects. The patients with stage 4 CKD were followed up until they progressed to stage 5, and in the second phase of the study, they underwent a 24-h Holter ECG monitoring after completion of 3 months of conventional haemodialysis treatment. RESULTS: In the first phase of the study, a reduction in cardiac sympathetic activity in CKD4 patients (significantly lower SDNN, SDANN/5 min, SD and VLF vs. HS) and worse autonomic function in CKD4+DM patients (significantly lower SDNN, SDANN/5 min, SD, VLF and LF/HF) vs. HS, DM and CKD4 was observed. After 3 months of dialysis therapy, the patients with CKD+DM showed a significant improvement only in the time-domain parameter SDANN/5 min, while the time-domain parameters SDNN, SDANN/5 min and SD were improved in CKD patients without diabetes. Frequency-domain parameters of HRV remained unchanged in both groups. CONCLUSIONS: CKD is associated with worse cardiac autonomic function. Haemodialysis therapy for 3 months improves some indices of HRV, and this effect is more pronounced in non-diabetic subjects. Our findings suggest that the improvement of HRV after the initiation of chronic dialysis therapy can ameliorate clinical outcomes and survival in patients with end-stage renal disease.

Association of matrix γ-carboxyglutamic acid protein levels with insulin resistance and Lp(a) in diabetes: A cross-sectional study.

AIMS: The risk of cardiovascular disease (CVD) and mortality is increased in patients with chronic kidney disease (CKD), with a background role of vascular calcification in the development of CVD also reported. Studies have demonstrated that high lipoprotein(a) (Lp(a)) levels accelerate the development of atherosclerolsis and are potentially involved in the vascular calcification. Matrix Gla Protein (MGP) seems to play an important role in vascular calcification. The aim of the study was to examine the potential association of MGP concentrations with Lp(a) and insulin resistance. METHODS: The study involved 100patients divided in four groups: 25 with both CKD stage 4 and Type2 Diabetes (DM) (Group-A), 25 with CKD4 without DM (Group-B), 25 non uremic patients with DM (Group-C) and 25 healthy subjects (Group-D). Serum glucose, Lp(a), MGP, plasma HBA1c and insulin were measured in all patients. Insulin resistance was estimated by the homeostasis model assessment equation (HOMA-IR). RESULTS: A significant positive linear association between MGP and Lp(a) levels (r=0.272, p=0.006) was noted, as well as between MGP and HOMA-IR levels (r=0.308, p=0.002). However, no significant linear association between Lp(a) and HOMA-IR levels was recorded. A similar positive association between MGP and insulin levels (r=0.204, p=0.042) was also found. CONCLUSION: This study concluded that diabetes coexisting with renal disease leads to extreme vascular calcification expressed by elevated MGP levels, resulting in higher frequency of cardiovascular disease in comparison to CKD patients without diabetes. The detected Lp(a) and MGP association in CKD4 patients may also represent the key to the complicated mechanism of their coexisting accelerated atherosclerosis and vascular calcification.

High prevalence of subclinical peripheral artery disease in Greek hospitalized patients.

BACKGROUND: Peripheral artery disease (PAD) represents a common manifestation of systemic atherosclerosis that is associated with an increased risk of cardiovascular death and ischemic events but one that may be underdiagnosed in clinical practice. The purpose of this study was to identify PAD using the ankle-brachial index (ABI) in hospitalized patients from a Department of Internal Medicine and to further investigate the association of this index with traditional cardiovascular risk factors. METHODS: We measured ABI in 990 consecutive patients (400 men and 590 women) aged 50 years or older (71.2+/-9.1) without a history or symptoms suggestive of PAD. ABI values below 0.90 were considered abnormal. RESULTS: PAD was detected in 356 patients (36%), and men had a higher prevalence than women (p<0.001). Hypertension (p<0.001), smoking (p<0.001), diabetes (p<0.05), male sex (p<0.001), and dyslipidemia (p<0.05) were statistically more frequent in patients with PAD, whereas obesity had no significant relation to PAD in our series. In a stepwise, logistic regression analysis, hypertension, male sex, diabetes mellitus, smoking, and dyslipidemia were found to be independent risk factors with odds ratios (95% confidence intervals) of 2.46 (1.85-3.27), 2.25 (1.66-3.05), 1.80 (1.32-2.47), 1.78 (1.31-2.42), and 1.64 (1.22-2.19), respectively. CONCLUSIONS: A simple ABI measurement revealed a large number of patients with unrecognized PAD. It is, therefore, recommended that ABI measurement should be included in the evaluation of cardiovascular risk in hospitalized patients aged 50 years or older.