<h2 id="hl0000188">Abstract</h2> <h2 id="hl0000190">Background</h2> <p id="hl0000191">Transcatheter aortic valve replacement (TAVR) can be complicated by anemia due to periprocedural bleeding, hemolysis, vascular events, or significant bleeding associated with antiplatelet therapy.</p> <h2 id="hl0000193">Objective</h2> <p id="hl0000194">We used the National Inpatient Sample (NIS) database to study the outcomes of patients who underwent TAVR and developed significant anemia requiring red blood cell (RBC) transfusion.</p> <h2 id="hl0000196">Methods</h2> <p id="hl0000197">This is a retrospective cohort study utilizing the NIS database from 2016 to 2017. We identified patients who underwent TAVR and required RBC transfusion using ICD-10 and PCS-10 codes. The primary outcome was all-cause inpatient mortality, and the secondary outcomes were the cost of hospitalization and length of stay (LOS). Student<span> </span><i>t</i><span> </span>-test, Chi-square, and ANOVA were utilized for statistical analysis where applicable. Multivariate logistic regression was used to adjust for potential confounders. STATA 15.0 was utilized for data analysis.</p> <h2 id="hl0000200">Results</h2> <p id="hl0000201">A total of 18,325 patients underwent TAVR in 2016–2017. Among them, 6.7 % of patients required RBC transfusion. Patients were relatively older in the transfusion group (81 yrs vs 79 yrs; p < 0.001). The mean cost of hospitalization was higher in the transfusion group (283,153 USD vs 208,939 USD; p < 0.001). The mean length of stay (LOS) was higher in the transfusion group (9.0 days vs 4.3 days; p < 0.001). Patients in the transfusion group had higher inpatient all-cause mortality compared to patients without transfusion (6.1 % vs 1.3 %; odds ratio 4.94; p < 0.001, 95 % CI 3.7–6.4). Inpatient mortality and LOS didn't differ by race or sex in the transfusion group. All-cause mortality, LOS, and cost of hospitalization were independently increased by transfusion after adjusting for potential confounders i.e. sex, race, hospital teaching status, hospital region, heart block, pacemaker, arrhythmias, heart failure, diabetes, pulmonary hypertension, CKD, and others using multivariate logistic regression.</p> <h2 id="hl0000203">Conclusion</h2> <p id="hl0000204">In patients undergoing TAVR, blood transfusion was associated with adverse outcomes including increased mortality, length of stay, and cost of hospitalization. The role of careful patient selection, judicious use of antiplatelets, anticoagulants, and pre-procedural optimization of anemia needs further investigation to optimize patient outcomes.</p>