4D.11: ARTERIAL STIFFNESS IN PATIENTS WITH ENDEMIC NEPHROPATHY UNDERGOING HEMODIALYSIS.

OBJECTIVE: Arterial stiffness (AS) is an independent risk factor of cardiovascular mortality in general and haemodialysis (HD) population. Endemic (Balkan) nephropathy (EN) is a chronic tubulointerstitial salt wasting nephropathy characterized with later onset of arterial hypertension (AH) which could also affect AS. Thus our aim was to analyse AS in EN patients compared with other end-stage renal disease patients undergoing HD.

DESIGN AND METHOD: A total of 186 HD patients (90 m, 96 w; 67.35 + 13.07 years) from 3 dialytic units and 2 endemic areas were enrolled. The exclusion criteria were: duration of dialysis < 3 months, atrium fibrillation, myocardial infarction or stroke in last 3 months, heart failure, arteriovenous anastomosis besides functional arteriovenous fistula. EN was diagnosed by modified WHO criteria. All patients were dialysed by European and KDIGO guidelines. Brachial blood pressure (BP) was measured with Omron M6 device and AS markers; pulse wave velocity (PWV) and aortic augmentation index (AIx) were measured by Arteriograph before mid-week dialysis.

RESULTS: There were no differences in sex, smoking status, type of vascular access, phosphate binder doses, vitamin D, hypertension and brachial BP between two groups. Non-EN patients had more antihypertensives drugs (p < 0.001), higher body mass index, waist circumference and diabetes. There were no differences in dialysis modalities except lower ultrafiltration in EN patients (p < 0.001). EN were significantly older (p < 0.001) with later start of dialysis. EN had lower values of phosphates (p < 0.001), CaxP (p < 0.001) and iPTH (p < 0.001), and significantly lower PWV (9.2 ± 1.6 vs.10.5 ± 1.9; p < 0.001). Using multiple linear regression models EN was the most significant independent negative predictor for PWV (p < 0.001) and AIx (p = 0.002). Using logistic regression non-EN patients had odds ratio for increased AS (PWV > 10 m/s OR 3.12; 1.72-5.82; p < 0.00001).

CONCLUSIONS: EN patients despite being older had lower PWV and AIx values. Even more, EN is an independent predictor of lower arterial stiffness. This could be explained with later onset of AH in pre-dialytic clinical course and probably with lower phosphate values due to tubulopathy. Better control of Ca and P during dialysis also contributes to observed lower AS in EN patients undergoing HD.