No vasodilator response to low-dose heparin in the forearm skeletal-muscle vascular bed

Recent reports show that heparin induces vasodilation. This heparin-induced vasodilation might interfere with the results of vascular studies using the perfused-forearm technique because the arterial catheter is often flushed with a heparin solution in those experiments. Therefore, we investigated the vascular effects of flushing an arterial catheter with a heparin solution compared with a placebo solution (NaCl 0.9%) in six healthy volunteers.

During the first half of each experiment, the arterial catheter was flushed several times with the placebo solution. In the second half, identical flushes were performed with a solution of heparin diluted in NaCl 0.9% (4U x ml(-1)).

Forearm blood flow (venous occlusion plethysmography) response was similar with heparin and placebo after all flushes.

We conclude that low-dose heparin in the solution to flush an arterial catheter has no short-term vasodilator effect in the human forearm vascular bed. Therefore, the results of studies using the perfused-forearm technique are not confounded by flushes with a low-dose heparin solution.