Timing of Platelet Rich Plasma Injections During Antithrombotic Therapy

The use of platelet rich plasma (PRP) spans across many fields owing to its role inhealing and as a natural alternative to surgery. PRP continues to grow however muchof the literature is anecdotal or case report based and there is a lack of controlledtrials to evaluate standards for PRP. The International Cellular Medical Society (ICMS)has developed guidelines to help with the safe advancement of PRP; however thereremains a gap in literature concerning the timing of PRP injections in patients who are onantithrombotic therapy. The importance of an intact platelet surface membrane allowsfor the appropriate release of the healing bioproteins and growth factors granting PRPtherapy its efficacy. This along with the proliferation of differentiated cells, enhancementof collagen synthesis, early angiogenesis and revascularization help promote the benefitsof regeneration. The intrinsic and extrinsic pathways of the coagulation cascade arevaluable in that disruption of this mechanism or prematurely activated platelets mayresult in limited efficacy. Anticoagulants and antiplatelet drugs are commonly used inpatients who are candidates for PRP. As antithrombotic agents affect platelet stability,they will have an effect on PRP efficacy and must be discontinued at an appropriatetime frame prior to injection therapy. Understanding the pharmacokinetics and plateleteffects can help guide discussion on the proper timing of discontinuation and resumptionof a particular antithrombotic agent. With future research, the establishment of clinicalpractice guidelines concerning PRP and antithrombotic therapy can help structure safeand efficacious means in which to promote healing and regeneration in a growing patientpopulation.Key words: Platelet rich plasma, antithrombotic therapy, coagulation, platelet activation,regenerative medicine, growth factors