Morris, Rohinton J.

Background/Hypothesis: Women have higher morbidity and mortality associated with CABG procedures than men. The extent intra-operative red blood cell (RBC) transfusions contribute to gender differences in surgical outcomes is not established. We hypothesized that women are at increased risk for RBC transfusions due to lower pre-op hematocrit (Hct) and blood volume, but that other factors may also contribute. Methods: Consecutive, non-reoperative CABG procedures from 189 institutions (2012 -2015) were reviewed. Gender differences and odds ratios for intra-operative transfusion were evaluated with logistic regression models adjusting for age, blood volume (Nadler formula-to normalize for height and weight), procedure acuity, net extracorporeal circuit prime volume, use of retrograde autologous priming, first Hct in OR, nadir Hct on cardiopulmonary bypass (CPB), volume added on CPB, ultra-filtration volume, urine output on CPB, and procedure duration. Results: Among 54,122 patients (25.3% female), 21.9% (n=11,901) received a RBC transfusion. Compared to men, female patients were older (66 yrs vs. 64 yrs, p<.001), had lower blood volumes (4.3L vs. 5.6L, p<.001), and lower pre-op Hct (32.9% vs. 37.2%, p<.001). Transfusion rates were 3-fold higher in women vs. men (45.1% vs 13.7%, p<.001). Even after adjustment for independent predictors of intra-operative transfusion, women remained at increased risk vs men (OR = 1.3, 95% CI = 1.2 -1.4). No gender differences in transfusion rates were observed for Hct 21%-23% (Figure). Conclusions: Women have an increased risk of intra-operative RBC transfusion vs men. After adjusting for height and weight, much of this risk is due to gender differences in pre-op Hct and blood volume, however a residual significant risk remained after adjustment. Perfusion strategies aimed at gender differences may minimize unnecessary transfusions. Future study on the impact of gender on transfusion practice in cardiac surgery is warranted.

Background— The incidence and impact of clinical stroke and silent radiographic cerebral infarction complicating open surgical aortic valve replacement (AVR) are poorly characterized. Methods and Results— We performed a prospective cohort study of subjects ≥65 years of age who were undergoing AVR for calcific aortic stenosis. Subjects were evaluated by neurologists preoperatively and postoperatively and underwent postoperative magnetic resonance imaging. Over a 4-year period, 196 subjects were enrolled at 2 sites (mean age, 75.8±6.2 years; 36% women; 6% nonwhite). Clinical strokes were detected in 17%, transient ischemic attack in 2%, and in-hospital mortality was 5%. The frequency of stroke in the Society for Thoracic Surgery database in this cohort was 7%. Most strokes were mild; the median National Institutes of Health Stroke Scale was 3 (interquartile range, 1–9). Clinical stroke was associated with increased length of stay (median, 12 versus 10 days; P =0.02). Moderate or severe stroke (National Institutes of Health Stroke Scale ≥10) occurred in 8 (4%) and was strongly associated with in-hospital mortality (38% versus 4%; P =0.005). Of the 109 stroke-free subjects with postoperative magnetic resonance imaging, silent infarct was identified in 59 (54%). Silent infarct was not associated with in-hospital mortality or increased length of stay. Conclusions— Clinical stroke after AVR was more common than reported previously, more than double for this same cohort in the Society for Thoracic Surgery database, and silent cerebral infarctions were detected in more than half of the patients undergoing AVR. Clinical stroke complicating AVR is associated with increased length of stay and mortality.