Hypertension in dialysis patients

Hypertension in long term dialysis patients has a significant effect on cardiovascular morbidity and the mortality of such patients. Important factors in the pathogenesis of hypertension in dialysis patients include retention of sodium and water, activation of the rennin-angiotensin system and the sympathetic nervous system, disorders of calcium and phosphate metabolism with osteogenic differentiation of vascular smooth muscle cells and calcification of arteries, vasoactive substance imbalance, endothelium dysfunction and erythropoietin therapy. The basis of treatment is diet with limited salt and fluid intake, restriction of phosphorus in the diet and treatment with phosphate binders, correct dialysis tactics and anti-hypertension medication. Unrestricted salt consumption and a high concentration of sodium in the dialysis solution, alongside reduced residual dieresis, lead to thirst and increased intake of fluids and subsequent water retention. In dialysis it is important to achieve an optimal "dry weight", i.e. body mass excluding surplus water in the organism. A sufficient length of haemodialysis ensures the removal (ultrafiltration) of excess fluid without episodes of hypotension. If the target blood pressure (< 140/90 mm Hg) cannot be achieved through diet and the maintenance of dry weight, anti-hypertension therapy is used. The optimal choice are blockers for the rennin-angiotensin system: they reduce the mortality of dialysis patients, reduce hypertrophy of the left ventricle, reduce the activity of the sympathetic nervous system, improve endothelial function and reduce oxidative stress. Some anti-hypertension medications (certain ACEIs and beta-blockers) are eliminated by dialysis and it is therefore necessary to adapt the choice of medication and the time of administration. There is a need for further controlled studies to determine the optimal therapy for hypertension in dialysis patients.

Keywords: dialysis treatment; hypertension; diet; dry weight; RAS blockers