LDL Apheresis for Arteriosclerosis Obliterans with Occluded Bypass Graft: Change in Prostacyclin and Effect on Ischemic Symptoms

Abstract

To study the mechanism of efficacy of low-density lipoprotein (LDL) adsorption for arte riosclerosis obliterans (ASO), eight ASO patients without indication for bypass surgery underwent LDL apheresis twice a week for 5 weeks and the change in prostaglandin I₂ (PGI ₂) and thromboxane A₂ (TXA₂) due to LDL apheresis was measured. The concentra tion of 6-keto-PGF_I,, a metabolite of PGI₂, in systemic venous blood significantly increased from 10.4 ± 1.8 to 42.0 ± 10.6 pg/mL (P < 0.05) after one session of LDL apheresis, while no significant change of TXB₂, a metabolite of TXA₂, was encountered. The ratio of 6-keto-PGF,,,/TXB₂ also rose dramatically from 0.213 ±0.044 to 0.522 ±0.128 (P < 0.05) . In five patients, the ischemic clinical symptoms improved and both the concentration of 6-keto-PGF_1α and the ratio of 6-keto-PGF_1α/TXB₂ increased significantly, whereas in three patients there was no effect on clinical symptoms and neither parameter changed. These results suggest that elevated production of PGI ₂ from vascular cells due to LDL apheresis might contribute to improvement of ischemic symptoms.