RESUMO
Recombinant activated factor VII (rFVIIa), developed and effective in managing inhibitors in haemophilia patients, is being widely used off-label as a "panhaemostatic agent" with ongoing controversy as to its benefits and risks in terms of controlling critical haemorrhage and improving patient outcomes. Current insights into haemostatic mechanisms have resulted in a better understanding of the central role of FVII/FVIIa and tissue factor in the localization and initiation of haemostasis. There is a plethora of case reports and series published on the use of rFVIIa in critical life-threatening haemorrhage and in perioperative settings associated with significant blood loss or the potential for catastrophic haemorrhage. Additionally, the literature is replete with reviews for the use of rFVIIa in various clinical settings, but there is a dearth of good evidence from randomized controlled trials for efficacy. Safety, especially from the thrombogenicity perspective, has been a major issue, but turns out to be less of a concern with thrombotic potential needing to be weighed against the anticipated benefits. Although there is some clinical trial and observational data supporting efficacy it has been difficult to recommend clear clinical practice guidelines, especially as clinical outcome data in terms of morbidity and mortality is limited. Some of the best evidence relates to reduction in allogeneic blood transfusion requirements. This in itself is important and probably clinically relevant in view of the accumulating evidence that allogeneic blood transfusion is an independent risk factor for poorer clinical outcome. It is unlikely that there will be adequate randomized clinical trials to better answer the question of efficacy, thus making data from registries of greater importance. Indeed, the process of establishing efficacy, safety and regulation of a therapeutic that is increasingly used off-label is not without significant difficulties.
