Early vascular aging (EVA) is a feature of chronic kidney disease(CKD) and pulse wave velocity(PWV) is independent predictor of premature cardiovascular(CV) mortality. High blood pressure(BP) and vascular calcifications contribute mostly to EVA in this group. Endemic nephropathy(EN), an environmental form of aristolochic acid nephropathy, is a chronic tubulointerstitial salt wasting nephropathy characterized with later onset and milder forms of hypertension (HT), and in line with this we hypothesized that arterial stiffness progresses slowlier in EN pts resulting in lower CV mortality.Design and method:
A total of 186 hemodialysed(HD) patients (90m, 96w; 67.35+13.07years) were enrolled. At the end of follow up, after 25 months, 97 pts were alive (52EN and 45non-EN). All patients were dialysed by the international guidelines. Brachial BP was measured with Omron M6 device and PWV was determined by Arteriograph before mid-week dialysis.Results:
There were no differences in gender, smoking status, type of vascular access, phosphate binder doses, vitamin D and dialysis modalities between two groups. At baseline and at the start of HD EN pts were significantly older (72. ± 37.1 vs 62.8 ± 15.1; p < 0.001), had shorter duration of HT prior commencement of HD than non-EN pts (36 vs. 84 months; p < 0.001). There were no differences in BP, but EN pts were treated with less antihypertensive drugs (p < 0.01). EN pts had lower values of P and CaxP (all p < 0.001) and significantly lower PWV values at baseline and at the end of follow-up period (9.2 ± 1.6 vs. 10.5 ± 1.9; 9.3 ± 1.3 vs. 10.5 ± 1.9, respectively; both p < 0.001). In multivariate analyses EN was independent predictor of high PWV. During the study period EN patients died significantly less frequently from CV events (12%vs.32%; p = 0.001), and had longer mean survival time (22.3 vs.18.2 months, p < 0.001). CV mortality was significantly lower in EN group (15.0% vs. 37.8%, HR0.32 [0.18,0.59], log-rank p = 0.0004), which remained significant after adjustment for other risk factors (aHR0.17 [0.06,0.49]). Baseline PWV > 10m/s was associated with higher risk for CV mortality(aHR1.88[1.42,2.49]).Conclusions:
Despite being older EN patients had lower PWV values. In EN, later onset of HT during predialytic clinical course, milder form of HT and better control of phosphate during HD therapy slowdown vascular aging and thus CKD progression, and importantly resulting in lower CV mortality and longer survival time. Opposite to EVA in other CKD, EN might be the case of slower vascular aging.