Impact of Dipyrone Administration on Postoperative Analgesia and Aspirin Effect in Patients Undergoing Coronary Artery Bypass Grafting: The Prospective Randomized DipASA Study.

Objective: The aim of the study was to investigate the impact of dipyrone administration on postoperative analgesia and acetylsalicylic acid (ASA) effect in patients undergoing coronary artery bypass grafting (CABG).

Design: A prospective randomized study.

Setting: Single-university hospital setting.

Participants: Ninety-eight patients who underwent CABG between April 2022 and May 2023.

Interventions: The ASA effect was measured at 6 time points with impedance aggregometry (Multiplate) and thromboelastography (TEG6s Platelet Mapping). Patients were randomized to 1 of 3 groups: intravenous ASA and dipyrone at the same time (group 1), intravenous ASA and dipyrone with a 2-hour delay (group 2), and intravenous ASA alone (group 3). Postoperative analgesic effects (numeric rating scale) and the prevalence of potential ASA non-response (defined as ASPI >40 U and TEG-ASA inhibition <50%) were recorded.

Measurements and main results: Of 90 analyzed patients, 80 took ASA preoperatively. All patients received intravenous ASA 100 mg from postoperative day 1. The effect of ASA did not significantly differ between the study groups at any time for either platelet function test. NRS values did not differ between the study groups at any time (p = 0.469). Patients in group 3 received significantly more additional co-analgesics than patients who received dipyrone (p = 0.005). ASA non-response was detected in 38.9% and 67.8% on the seventh postoperative day, respectively.

Conclusions: Dipyrone given after CABG seems safe and did not show any significant effect on platelet inhibition after ASA administration. Patients taking dipyrone postoperatively need significantly fewer additional coanalgesics. The ASA effect on platelet function should be checked at least once after surgery.