Currently there are no national guidelines or large scale studies to guide bridging NOACs for procedures.
The relatively short half-life for these agents makes it likely that traditional bridging as is practiced for warfarin is not necessary.9 However, this represents a double-edged sword; withholding anticoagulation for two doses (such as if a patient becomes ill or a clinician is overly cautious around the time of a procedure) may leave the patient unprotected.
The final question with the new agents is their anti-inflammatory effects. We know that heparin and LMWH have significant pleiotropic effects that are not necessarily related to their anticoagulant effects. These effects are important in order to decrease the inflammatory nature of the thrombus and its effect on the vein wall. We do not know if the new oral agents have similar effects, as this has never fully been tested. In view of the fact that two of the agents are being used as monotherapy agents without any heparin/LMWH bridge, the anti-inflammatory properties of these new agents should be defined to make sure that such a bridge is not necessary.
So, in summary, although these agents have much to offer, there are many questions that remain to be addressed and answered before they totally replace traditional approaches to anticoagulation, in the realm of VTE. It must not be overlooked that despite all the benefits, they also each carry a risk of bleeding as they all target portions of the coagulation mechanism. We caution that, as with any “gift horse,” physicians should perhaps examine the data more closely and proceed with caution.
Thomas Wakefield, MD, is the Stanley Professor of Vascular Surgery; head, section of vascular surgery; and director, Samuel and Jean Frankel Cardiovascular Center. Andrea Obi, MD, is a vascular surgery fellow and Dawn Coleman MD, is the program director, section of vascular surgery, all at the University of Michigan, Ann Arbor. They reported having no conflicts of interest.
References
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