Does preoperative antiplatelet therapy increase the risk of hemorrhagic complications associated with regional anesthesia?

Hospital records of 805 patients given 1013 spinal or epidural anesthetics were retrospectively studied to determine whether preoperative antiplatelet medications were significantly related to the development of hemorrhagic complications. Preoperative antiplatelet medications were taken by 391 (39%) patients, including 113 patients receiving multiple drugs. No patient developed signs of spinal hematoma or postoperative neurologic deficits. However, patients receiving antiplatelet medications had an increased incidence of "minor" hemorrhagic complications such as blood-tinged cerebrospinal fluid or blood aspirated through the spinal or epidural needle or catheter (P less than 0.05). When considered independently as risk factors, age and epidural anesthesia were not statistically significant determinants of the incidence of minor hemorrhagic complications. The combination of increased age and epidural (but not spinal) anesthesia was associated with a 4.5% incidence of minor hemorrhagic complications (P less than 0.05). Aspiration of blood through the spinal or epidural needle may not imply an increased risk for serious hemorrhagic complications. Clinical and laboratory screening of patients for preexisting coagulopathies and atraumatic needle placement may reduce the risk of minor hemorrhagic complications involved in patients given antiplatelet medications before the induction of regional anesthesia.