Antiplatelet Timing before Cardiac Surgery

As the number and types of antiplatelet medications increase—as do the number of indications for which patients take these drugs—researchers continue to look at the age-old question of when to stop these drugs if surgery is necessary. Stopping them too soon increases risk of clotting. Stopping them too late increases risk of excessive blood loss.

A team of researchers from Leiden University Medical Center in the Netherlands has published a randomized prospective study of patients needing cardiac bypass surgery who were also taking antiplatelet medications. They looked for the optimal time to stop acetylsalicylic acid (ASA) or ASA combined with clopidogrel (ASA+Clo) before surgery.

This large study (N= 1065) divided patients into 3 groups depended in their antiplatelet medication regimens in the 10 days prior to surgery:

• ASA only (n = 662)
• ASA+Clo (n = 290) or
• No antiplatelet medication (n = 113)

The researchers used a series of multiple linear regression models, one for each preoperative day (running from Day -10 up to -1) to find the best estimate for the optimal stop day. They also evaluated major adverse cardiovascular and cerebral events (MACCE).

The researchers were unable to identify an optimal stop day for patients using ASA or ASA+Clo prior to their cardiac bypass surgery.

Patients who took their last dose of ASA on Day -2 or earlier were significantly less likely to need platelet transfusions compared to those who continued taking ASA up to surgery. The difference was 7% vs. 13 % respectively.

The researchers found no association between stop day and the occurrence of MACCE.

Key guidelines for CABG surgery recommend administering preoperative ASA without discontinuation and discontinuing preoperative clopidogrel at Day -5. The researchers note that they found no clinically relevant effect on blood loss indicating an optimal stop day for ASA alone or in combination with clopidogrel.