Clinical application of procedural platelet monitoring during percutaneous coronary intervention among patients at increased bleeding risk

Assessment of platelet inhibition by point-of-care testing in neuroendovascular procedures

Antiplatelet agents are an important component of the preventive strategies currently used in clinical practice to minimize the risk of thromboembolic events during and after endovascular procedures. Because of the variability in the response to antiplatelet agents, measuring the degree of platelet inhibition may help identify and properly treat poor responders. POC testing is defined as diagnostic testing at or near the site of patient care. Knowledge of the specifics of these devices among practicing neurointerventionalists is relatively limited. In this article, the different POC devices available are presented, and their clinical utility in relation to endovascular procedures is discussed.

Increased blood product use among coronary artery bypass patients prescribed preoperative aspirin and clopidogrel

BACKGROUND

The administration of antiplatelet drugs before coronary artery bypass graft surgery (CABG) is associated with an increased risk of major hemorrhage and related surgical reexploration. Little is known about the relative effect of combined clopidogrel and aspirin on blood product use around the time of CABG. We evaluated the associated risk between the combined use of aspirin and clopidogrel and the transfusion of blood products perioperatively.

METHODS

We retrospectively studied a cohort of 659 individuals who underwent a first CABG, without concomitant valvular or aortic surgery, at a single large Canadian cardiac surgical centre between January 2000 and April 2002. The four study exposure groups were those prescribed aspirin (n = 105), clopidogrel (n = 11), the combination of both (n = 46), or neither drug (n = 497), within 7 days prior to CABG. The primary study outcome was the excessive transfusion of blood products during CABG and up to the second post-operative day, defined as > or = 2 units of packed red blood cells (PRBC), > or = 2 units of fresh frozen plasma, > or = 5 units of cryoprecipitate or > or = 5 units of platelets. Secondary outcomes included the mean number of transfused units of each type of blood product.

RESULTS

A greater mean number of units of PRBC were transfused among those who received clopidogrel alone (2.9) or in combination with aspirin (2.4), compared to those on aspirin alone (1.9) or neither antiplatelet drug (1.4) (P = 0.001). A similar trend was seen for the respective mean number of transfused units of platelets (3.6, 3.7, 1.3 and 1.0; P < 0.001) and fresh frozen plasma (2.5, 3.1, 2.3, 1.6; P = 0.01). Compared to non-users, the associated risk of excessive blood product transfusion was highest among recipients of aspirin and clopidogrel together (adjusted OR 2.2, 95% CI 1.1-4.3). No significant association was seen among lone users of aspirin (adjusted OR 1.0, 95% CI 0.6-1.6) or clopidogrel (adjusted OR 0.7, 95% CI 0.2-2.5), compared to non-users.

CONCLUSIONS

While combined use of aspirin and clopidogrel shortly before CABG surgery may increase the associated risk of excess transfusion of blood products perioperatively, several study limitations prevent any confident conclusions from being drawn. Beyond challenging these findings, future research might focus on the value of both intraoperative monitoring of platelet function, and the effectiveness of antifibrinolytic agents, at reducing the risk of postoperative bleeding.