['The objective of this study was to evaluate the effect of an intra-aortic filter on postoperative outcomes in high-risk cardiac surgical patients.', 'An intra-aortic filter was used in 316 (4.9%) of 6442 cardiac surgical cases from 2003 to 2013. A retrospective analysis of the Society of Thoracic Surgeons (STS) registry data was performed for 204 patients with filter placement who underwent coronary artery bypass grafting (CABG) (n = 89), valve replacement (n = 63) or combined CABG and valve replacement (n = 52), matched with 1224 patients without filter placement by STS mortality scores based on propensity scores. Generalized linear modelling was used to compare rates of complications as well as the length of stay and time in the intensive care unit (ICU). A P-value < 0.05 was considered significant.', 'Overall, patients with filters before matching had a significantly higher risk of death than did the patients without filters: 12.0% of patients with filters had an STS mortality risk score ≥4 vs 7.7% of patients without filters (P = 0.027). After analysis of the composite end-point of all STS major morbidities, the matched filter group had fewer overall complications (6.8 vs 13.2%, P = 0.02). The rate of postoperative respiratory failure was lower in the filter group (2.5 vs 7.0%, P = 0.01). Rates of stroke and new-onset haemodialysis, while not statistically different, were almost 50% lower in the filter group. Length of stay in the hospital and in the ICU was not significantly different; however, in patients with postoperative complications, time in the ICU (163 vs 189 h, P = 0.02) was shorter for the filter patients.'] Does selective use of the intra-aortic filter in high-risk cardiac surgical patients lead to better postoperative outcomes?