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Low molecular weight (LMW)-heparin was used as the sole anticoagulant during hemodialysis and hemofiltration in a pilot study on 32 patients. A LMW-heparin dose corresponding to 50% of the patients usual unfractionated, standard (UF)-heparin dose was found to produce comparable plasma heparin levels (anti-FXa-activity). No thrombosis of the extracorporal system and no bleeding complications occurred at this LMW-heparin dose. In contrast to UF-heparin, LMW-heparin produced only slight increases in PTT and thrombin time in all patients. Lipoprotein lipase was stimulated only marginally by LMW-heparin, with a correspondingly reduced release of free fatty acids. Both heparin species caused similar elevations in factor VIII and fibrin monomers, thus excluding a difference in coagulation activation. On the basis of these results, long-term studies have been started at four nephrology centers. To date, 26 patients have been treated with LMW-heparin for 6 months. A LMW-heparin dose was used that produced plasma anti-FXa-activity of 0.5 to 0.9 U/ml (initial dose: 30 to 40; dose/hr: 8 to 15 anti-FXa-units/kg body wt). PTT and thrombin time were only increased by 5 sec on average. Surprisingly, the elevated pre-dialysis levels of factor VIII and fibrin monomers decreased during this 6-month period. Bleeding complications did not occur and thrombotic complications were not observed when the anti-FXa levels were above 0.5 U/ml. LMW-heparin, therefore, appears to be a good alternative to UF-heparin for dialysis patients and may present less risk of bleeding because of its reduced effect on PTT, thrombin time, and thrombocytes.

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Long-term survival and morbidity in regular hemofiltration treatment is evaluated in two groups of patients with chronic renal insufficiency bearing different categories of risk. In one group of patients with low-risk (restriction of age, exclusion of diabetes mellitus and vascular diseases), complications during regular hemofiltration treatment (115 patients, 5,196 patient months) are compared to those of regular hemodialysis treatment (132 patients, 6,690 patient months). In a second group of patients with ‘high-risk’ (inclusion of diabetic nephropathy and cerebro- or cardiovascular diseases), hemofiltration (57 patients, 1,428 patient months) is compared to continuous ambulatory peritoneal dialysis (CAPD; 68 patients, 1,464 patient months). Long-term survival rates (8 years in the first and 5 years in the second group) did not show significant differences for hemofiltration and hemodialysis in the first group or for hemofiltration and CAPD in the second one. Main reasons for death in both groups were cardiovascular or cerebrovascular complications, and in the CAPD group infections (peritonitis, pneumonia), being similarly significant. Important differences between hemofiltration and hemodialysis on the one hand, and hemofiltration and CAPD on the other, could be demonstrated concerning morbidity, expressed in days of hospitalization per months of treatment. Hypotension, cardiovascular and cerebrovascular diseases, especially, necessitated significantly less frequent hospitalization of hemofiltration patients than of hemodialysis or CAPD patients; main reasons for hospitalization of hemodialysis patients being fistula complications and hypertension and for CAPD patients being infection, cardiac insufficiency, cerebrovascular disease and hypotension. In the second group, the frequency of complications of diabetes mellitus (retinopathy, angiopathy) was significantly higher in hemofiltration than in CAPD treatment. As has been shown earlier for short-term treatment, hemofiltration may exhibit its main advantage over hemodialysis in patients suffering from vascular complications also with long-term observation, thus ameliorating the quality of treatment.

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