Platelet aggregometry may not identify clopidogrel-treated patients at high risk of peri-operative bleeding in dialysis access surgery: A pilot study

Patients treated with Clopidogrel are usually instructed to discontinue treatment for 7 days prior to surgery because of concern for excessive peri-operative blood loss. Limited data exist regarding blood loss resulting from continuing treatment with Clopidogrel. Our goal was to compare peri-operative blood loss in Clopidogrel (CC) treated patients with Non-Clopidogrel (NC) patients undergoing upper extremity dialysis access surgery. Methods: Following informed consent, 23 patients, 18-90 years old were enrolled in a pilot, prospective study. Nine patients continued treatment with Clopidogrel, while 14 patients had no exposure to the drug. Vascular fistula or graft placement was accomplished under brachial plexus anesthesia and sedation. ADP (adenosine diphosphate) induced inhibition of platelets was assayed by Impedance-based Whole Blood Platelet Aggregation (IWBPA) on immediate preoperative blood sample obtained from all participants to determine baseline platelet aggregation status (Figure 1). Intra-operative blood loss (IBL) was estimated from suction canister output and sponge weights. Interventions such as blood or blood product transfusion were noted. Postoperative bruising or bleeding for up to 24 hours was recorded. Results: Nine (39.2%) of study participants were in the Clopidogrel group and 14 (60.8%) in the Non-Clopidogrel group. There was no correlation between IWBPA levels and IBL. No study participants developed postoperative bruising or hematomas. No blood or blood products were administered. Conclusion: Continued peri-operative treatment with Clopidogrel did not increase IBL or postoperative bruising compared to no Clopidogrel patients. IWBPA values did not correlate with IBL, and represented a poor predictor of peri-operative blood loss in Clopidogrel treated patients with end stage renal disease.