Relation of race (Asian, African-American, European-American, and Hispanic) to activated clotting time after weight-adjusted bolus of heparin during percutaneous coronary intervention.

A weight-adjusted bolus of heparin (70 to 100 IU/kg) is recommended to achieve adequate anticoagulation during percutaneous coronary intervention (PCI). Proper dosing is mandatory to avoid bleeding and thrombotic complications. We investigated whether sensitivity to heparin is affected by difference in race. We performed a retrospective study with 874 consecutive PCI cases in our catheterization laboratory. The amount of initial heparin bolus (international units) per weight and subsequent activated clotting time (ACT; seconds) were obtained. Patients were divided into 4 categories based on race: Asian, African-American, European-American, and Hispanic. Multiple regression analysis was performed to validate the variables that determine the ACT. After adjusting for these variables, analysis of variance revealed the presence of a significant racial difference in ACT (p = 0.002). Successively, Student-Newman-Keuls test and Bonferroni t test revealed that Asian patients have higher ACT levels compared to other racial groups (p <0.03 for Asian vs others, p >0.26 between non-Asian groups). There was a positive relation between ACT and Asian race (p = 0.0004). Further analyses showed that Asians require 10 IU/kg less heparin per weight than other racial groups to achieve the same goal of ACT. In conclusion, decreased heparin dosing should be considered for Asian patients undergoing PCI.