Effect of Low Molecular Weight Heparin on Bone Metabolism and Hyperlipidemia in Patients on Maintenance Hemodialysis

The effect of low molecular weight heparin (LMWH) on serum lipid profile in hemodialysis remains controversial and its effect on bone metabolism has not been studied. A crossover study was conducted in 40 patients on stable hemodialysis using unfractionated heparin (UFH) for more than 24 months. These patients were then treated with a LMWH (nadroparin-Ca) for 8 months during hemodialysis and subsequently switched back to UFH for 12 months. Serum lipid profile, biochemical markers for bone metabolism, and bone densitometry (BMD) were monitored at four-month intervals while all medications remained unchanged.

Cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), lipoprotein(a) (Lp(a)), apolipoprotein B (Apo B) were raised in 35%, 29%, 12%, 24% and 24% of patients respectively. High-density lipoprotein-cholesterol (HDL-C) and apolipoprotein A1 (Apo A-1) were reduced in 47% and 9% of patients. Bone-specific alkaline phosphatase (BALP) and intact osteocalcin (OSC), both reflecting osteoblastic activity, were raised in 65% and 94% of patients. Tartrate-resistant acid phosphatase (TRACP) reflecting osteoclastic activity and parathyroid hormone (PTH) were elevated in 35% and 88% of patients. Following LMWH treatment, TC, Tg, Lp(a) and Apo B were reduced by 7%, 30%, 21% and 10% respectively (p<0.05 or <0.01) while Apo A-1 were raised by 7% (p<0.01). Simultaneously, TRACP was reduced by 13% (p<0.05). These biochemical changes were detected soon after 4 months of LMWH administration. Although BMD values in our patients were lower than those of age-matched normal subjects, significant changes were not observed with LMWH treatment. After switching back to UFH for hemodialysis, these biochemical indices reverted to previous values during UFH treatment with a significant higher level in TC and Apo B while serum Apo A-1 remained elevated. Our study suggests LMWH may partially alleviate hyperlipidemia and, perhaps, osteoporosis associated with UFH administration in patients on maintenance hemodialysis.

Where and When To Inject Low Molecular Weight Heparin in Hemodiafiltration? A Cross Over Randomised Trial

Background and Objective

Low molecular weight heparins (LMWHs) are small enough to pass large pore dialysis membranes. Removal of LMWH if injected before the start of the session is possible during high-flux dialysis and hemodiafiltration. The aim of this study was to determine the optimal mode (place and time) of tinzaparin administration during postdilution hemodiafiltration.

Study Design, Setting, Patients

In 13 chronic hemodiafiltration patients, 3 approaches of injection were compared in a randomised cross over trial: i) before the start of the session at the inlet blood line filled with rinsing solution (IN₀), ii) 5 min after the start at the inlet line filled with blood (IN₅) and iii) before the start of the session at the outlet blood line (OUT₀). Anti-Xa activity, thrombin generation, visual clotting score and reduction ratios of urea and beta2microglobulin were measured.

Results

Anti-Xa activity was lower with IN₀ compared with IN5 and OUT₀, and also more thrombin generation was observed with IN₀. No differences were observed in visual clotting scores and no clinically relevant differences were observed in solute reduction ratio. An anti-Xa of 0.3 IU/mL was discriminative for thrombin generation. Anti-Xa levels below 0.3 IU/mL at the end of the session were associated with worse clotting scores and lower reduction ratio of urea and beta2microglobulin.

Conclusions

Injection of tinzaparin at the inlet line before the start of postdilution hemodiafiltration is associated with loss of anticoagulant activity and can therefore not be recommended. Additionally, we found that an anti-Xa above 0.3 IU/mL at the end of the session is associated with less clotting and higher dialysis adequacy.

Trial Registration

Clinicaltrials.gov NCT00756145

The impact of haemodialysis-associated variables on lipid profile in Egyptian haemodialysis population

INTRODUCTION

Haemodialysis (HD) patients appear to have particular susceptibility for cardiovascular (CV) diseases with lipid abnormalities among its significant contributors. However, there is controversy concerning the combined effect on lipid constituents during HD of the three commonly used variables; the type of heparin, dialysis membrane and the constituent of dialysate buffer bases. Consequently, this controlled prospective study was thought of.

PATIENTS

Randomly 63 patients were assigned from Urology and Nephrology haemodialysis (HD) unit, Mansoura, Egypt for the planned study. Their mean age was 45.79 +/- 13.11 years. Fourteen patients with end-stage renal disease (ESRD) served as control group for the remaining 49 HD patients. They were subdivided according to the HD duration (< and > 1 year), anticoagulant used (unfractionated [UFH] and low-molecular weight heparin [LMWH, Enoxaparin), membrane type (Hemophane [HP] and polysulfone [PS] membrane) and dialysate buffer bases (bicarbonate versus acetate based).

METHODS

Determining the fasting lipid value of total cholesterol (TC) and triglycerides (TG) as well as lipoproteins including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and lipoprotein (a) [Lp (a)] was completed.

RESULTS

Bicarbonate dialysate was associated with significantly lower TG (134.7 +/- 11 mg/dl vs. 153 +/- 14 mg/dl, p = 0.004), higher HDL-C (33.1 +/- 3 vs. 28.3 +/- 2, p = 0.0002) and subsequently better atherosclerosis risk ratio [TC/HDL-C (ARR)] (6.02 +/- 0.09 vs. 5.3 +/- 0.9, p = 0.001) despite its insignificant effect on TC and LDL-C. However, logarithm (log) Lp (a) level was significantly higher (1.92 +/- 0.05 vs. 1.82 +/- 0.04 p = 0.001) in comparison with acetate dialysate. Membrane type was not influential in those dialyzed for < 1 year before intervention while after a year of HD, PS (n = 11) compared to HP filters (n = 11) significantly lowered TC (151.7 +/- 16 vs. 172.6 +/- 12, p = 0.003), TG (127.8 +/- 15 vs. 155.7 +/- 15, p = 0.004), LDL-C (122.1 +/- 5 vs. 130.6 +/- 7, p = 0.006) levels as well as ARR (5.9 +/- 0.5 vs. 5.4 +/- 0.3, p = 0.02). Likewise was the reduction in log Lp (a) (1.9 +/- 0.03 vs. 1.8 +/- 0.04, p = 0.002) with insignificant effect on HDL-C. After 6 months, Enoxaparin caused significant improvement of TC (0.0004), TG (p = 0.018), LDL-C (p = 0.006), HDL-C (0.041) and Lp (a) (0.047) compared to UFH. Patients who continued on Enoxaparin for 3 more months displayed an even better attenuation in most of lipid parameters whilst continuation of UFH was insignificant. Switching few patients (n = 4) from UFH to LMWH for 3 months resulted in significant lowering of TC (153 +/- 7 vs. 177.7 +/- 3, p = 0.01), TG (127.5 +/- 5 vs. 137.3 +/- 4, p = 0.03) and LDL-C (124.7 +/- 5 vs. 127.5 +/- 5, p = 0.005). However, switching equal number of patients from LMWH to UFH caused no significant change.

CONCLUSION

Dyslipidaemia in Egyptian haemodialysis patients was improved when bicarbonate-based haemodialysis, the use of polysulfone membrane, and more so when the low-molecular weight heparin Enoxaparin were used.

A single bolus of a low molecular weight heparin to patients on haemodialysis depletes lipoprotein lipase stores and retards triglyceride clearing

BACKGROUND

Low molecular weight heparins (LMWH) are increasingly used during haemodialysis (HD) to prevent clotting in the extracorporeal devices. It has been suggested that LMWH release endothelial-bound lipoprotein lipase (LPL) less efficiently than unfractionated heparin (UFH) does and thereby cause less disturbance of lipid metabolism. Evidence from in vitro studies and from animal experiments indicate, however, that both types of heparin preparations have the same ability to release endothelial LPL, but LMWH are less effective in preventing uptake and degradation of LPL in the liver. Model studies in humans indicate that LMWH cause as much depletion of LPL stores and impaired lipolysis of triglyceride (TG)-rich lipoproteins as UFH does.

METHODS

Two anticoagulant regimes based on present clinical practice were compared in nine HD patients. UFH was administered as a primed infusion, whereas the LMWH (dalteparin) was given only as a single bolus pre-dialysis. Blood was sampled regularly for LPL activity and TG.

RESULTS

LPL activity in blood was significantly lower during the dialysis with dalteparin. To explore the remaining activity at the endothelium, a bolus of UFH was given after 3 h of dialysis. The bolus brought out about the same amount of LPL, regardless of whether UFH or dalteparin had been used during dialysis. The increase in TG was significantly higher during dialysis with dalteparin.

CONCLUSIONS

This study indicates that a single bolus of dalteparin pre-dialysis interferes with the LPL system as much as, or more than an infusion of UFH does.