Heparin-induced decrease in circulating antithrombin-III

Risk associated with heparin withdrawal in ischaemic cerebrovascular disease

Intravenous heparin is frequently used to treat thromboembolic disease, but the consequences of stopping heparin have not been studied systematically. To determine whether discontinuing heparin poses a clinical risk, we examined the charts of 378 patients treated with heparin for transient ischaemic attack (TIA), reversible ischaemic neurological deficit, or ischaemic stroke from October 1979 to June 1985. Clinical deterioration, or a new TIA or stroke was more likely (p = 0.01) during the 24 hours after heparin was stopped in patients not already on aspirin or warfarin (10/143, 7%) than in patients receiving aspirin or warfarin before heparin withdrawal (3/215, 1%). Stopping heparin in patients not receiving aspirin or warfarin appears to expose them to an increased risk for TIA, stroke, or clinical deterioration.

Intermittent heparin treatment does not induce hypercoagulability in haemodialysed patients

Antithrombin-III (AT-III) and factor VIII coagulant (F VIII:C) and antigenic (F VIII:RA) activities have been studied in nine conservatively treated and 26 dialysed uraemic patients. AT-III levels were not significantly different from those of controls in either group. Among dialysed patients, those who had experienced thrombotic occlusions of the vascular accesses could not be distinguished from the remaining patients on the basis of their AT-III levels. Both F VIII:C and F VIII:RA were slightly higher than in controls in conservatively treated patients, but significantly higher in haemodialysed patients, especially in those who had never experienced thrombotic complications of the vascular accesses. No acute changes were observed in either the AT-III or F VIII:C/F VIII:RA ratio in five patients given heparin therapy during a dialytic session or in the interdialytic period. Thus repeated intermittent heparin treatment does not induce a hypercoagulable state in haemodialysed patients.

Priapism as a complication of long-term intravenous nutrition

A case of priapism following prolonged intravenous nutrition is reported. The small amounts of heparin as received by our patient would tend to minimise a risk of hypercoagulability. However, the administration of intravenous feeding agents and the concomitant metabolic acidosis may have enhanced this risk.