Background and objective: Thrombosis of vascular anastomosis in the field of reconstructive microsurgery is a clinical problem of extraordinary importance for the devastating consequences for affected patients. Sildenafil has been shown to be relaxing vascular action on the peripheral vascular system in vivo and have an ability to reduce platelet aggregation. There is no study up to date on the effect of sildenafil on microvascular anastomosis, neither experimental studies nor clinical settings. The main objective of this research is to define the double effect of sildenafil (vasodilator and antiplatelet) in microvascular anastomosis.

Materials and methods: A purposeful thrombotic back-wall stitch was performed in the groin flap pedicle to obtain an anastomosis with thrombotic potential where the drug effect was studied.

Results: Data in the experimental group treated with papaverine or sildenafil indicate a considerable decrease in the percentage of necrotic flaps (20% necrotic flaps in papaverine group versus 30% necrotic flaps in sildenafil group) in comparison with control group (60% necrotic flaps). In papaverine group, in 100% cases, flap necrosis was established in the first 24 h, but in sildenafil group, 66% flap necrosis was established between the second and the seventh postoperative days.

Conclusion: The study did not demonstrate significant differences between the groups, but it does suggest a benefit in applying papaverine and sildenafil in the anastomosis with already thrombogenetic disease, compared to the non application of antithrombotic drugs. The establishment of thrombosis in the necrotic flaps in the group treated with sildenafil was later than in the group treated with papaverine, with a statistical trend but without becoming significant.

Key words: microsurgery; sildenafil; thrombosis; back-wall stitch