Circulation 60,475 • Volume 13, No. 1 • Spring 1998

Additional Input on LMWH Sought at ASRA Forum

Denise Wedel, M.D.

The American Society of Regional Anesthesia (ASRA) organized a symposium of experts held May 2-3, 1998, to examine guidelines for regional anesthesia in the anticoagulated patient. This consensus meeting is charged with developing guidelines and recommendations for all anticoagulant drug therapy with an emphasis on LMWH therapy. The resulting discussion and recommended guidelines will be published in a supplement to Regional Anesthesia and highlights will be presented at the ASRA annual meeting in Seattle, May 15-18. In the meantime, caution should be exercised in patients receiving these medications, and complications should be reported to the FDA. Although this complication is a serious one, the benefits of regional anesthesia in the surgical population are undeniable and must be considered as well. Hopefully, an acceptable balance can be achieved by careful consideration of the facts and acceptance of reasonable guidelines designed to protect both the patient and the practitioner.

By way of background, note that a recent FDA public health advisory reported the occurrence of 30 spontaneous safety reports as of November 1997, describing epidural or spinal hematomas in patients undergoing spinal or epidural anesthesia in the presence of enoxaparin sodium, a low molecular weight heparin (LMWH). The majority of these cases occurred in elderly females undergoing orthopedic surgery. LMWH therapy has a good safety record in Europe where it has been used in smaller, less frequent doses. Enoxaparin was released by the FDA for general use in the United States in May 1993, and the management of regional anesthesia in the face of LMWH therapy is still unclear. In a review of this topic in the October 1997 issue of Anesthesia and Analgesia, Terese Horlocker, M.D., and John Heit, M.D., cite several patient, surgical and anesthetic factors which may contribute to this serious complication. These include the higher dosage and more frequent timing of the dose recommended in this country, as well as the use of indwelling spinal or epidural catheters. Concomitant use of drugs affecting hemostasis and traumatic needle puncture are also cited. A pending editorial in Anesthesia and Analgesia by Drs. Horlocker and Wedel addresses this controversy and reiterates the need for reassessment of this new antithrombotic regimen and its role in perioperative regional anesthesia and pain management. This is also the goal of the ASRA symposium.

Dr. Wedel, a faculty member at the Mayo Clinic, is President of the American Society of Regional Anesthesia.