Background/ObjectivesProthrombin complex concentrates (PCC) are increasingly administered off‐label in the United States to treat bleeding in cardiovascular surgical patients and carry the potential risk for acquired thromboembolic side‐effects after surgery. Therefore, we hypothesized that the use of low‐dose 3‐factor (3F) PCC (20‐30 IU/kg), as part of a transfusion algorithm, reduces bleeding without increasing postoperative thrombotic/thromboembolic complications.Materials/MethodsAfter IRB approval, we retrospectively analysed 114 consecutive, complex cardiovascular surgical patients (age > 18 years), between February 2014 and June 2015, that received low‐dose 3F‐PCC (Profilnine®), of which seven patients met established exclusion criteria. PCC was dosed according to an institutional perioperative algorithm. Allogeneic transfusions were recorded before and after PCC administration (n = 107). The incidence of postoperative thromboembolic events was determined within 30 days of surgery, and Factor II levels were measured in a subset of patients (n = 20) as a quality control measure to avoid excessive PCC dosing.ResultsTotal allogeneic blood product transfusion reached a mean of 12·4 ± 9·9 units before PCC and 5·0 ± 6·3 units after PCC administration (P < 0·001). The mean PCC dose was 15·8 ± 7·1 IU/kg. Four patients (3·8%) each experienced an ischaemic stroke on postoperative day 1, 2, 4 and 27. Seven patients (6·5%) had acquired venous thromboembolic disease within 10 days of surgery. Median factor II level after transfusion algorithm adherence and PCC administration was 87%.Conclusions3F‐PCC use for refractory bleeding after cardiovascular surgery resulted in reduced transfusion of allogeneic blood and blood products. Adherence to this algorithmic approach was associated with an acceptable incidence of postoperative thrombotic/thromboembolic complications.