Impact of Significant Hemoglobin Drop without Bleeding in Patients Undergoing Transcatheter Aortic Valve Replacement

Background Hemoglobin (Hgb) drop without bleeding is common among patients undergoing transcatheter aortic valve replacement (TAVR); however, the clinical implications of significant Hgb drop have not been fully evaluated. We sought to describe clinical phenotype and outcomes of patients with significant Hgb drop without bleeding. Methods Consecutive patients undergoing TAVR at our institution from 2011-2021 were retrospectively reviewed. Three groups were assessed: No Hgb Drop and No Bleed (NoD-NoB – reference group), Hgb Drop with Bleed (D-wB), and Hgb Drop and No Bleed (D-NoB). Hgb drop was defined as ≥3 g/dL decrease from pre-to post-TAVR. Outcomes of interest were in-hospital death and 1-year all-cause mortality. Results A total of 1,851 cases with complete Hgb data were included: NoD-NoB: n=1,579 (85.3%); NoD-NoB: n=49 (2.6%); D-wB n=223 (12.6%). Compared to NoD-NoB, D-NoB were older (81.1 vs. 78.9 years) with higher pre-procedure Hgb (12.9 vs. 11.7 g/dL). In-hospital death rate was higher among patients with D-NoB vs. NoD-NoB (4.5% vs. 0.8%, p<0.001) and similar to D-wB (4.5% vs. 4.1%, p=0.999). Predictors of in-hospital death were D-NoB (odds ratio [OR]: 3.45; 95% confidence interval [CI]: 1.32-8.69) and transfusion (OR: 10.6; 95% CI 4.25-28.2). Landmark survival analysis found that D-NoB experienced one-year mortality rate comparable to NoD-NoB, while D-wB had higher mid-term mortality (HR: 3.2; 95% CI: 1.83-5.73), and transfusion continued to impact mortality (HR: 2.5; 95% CI 1.79-3.63). Conclusion Hemoglobin drop without bleeding is common among patients undergoing TAVR and may represent a higher risk of peri-procedural death. Blood transfusion increases short-and mid-term mortality risk in patients with and without bleeding, supporting a restrictive transfusion strategy. What Is Known; What the Study Adds What is Known - Hemoglobin drop without overt bleeding may be seen after transcatheter aortic valve replacement (TAVR); however, its incidence and impact on clinical outcomes is unknown. What the Study Adds - Hemoglobin drop without a source of bleeding is not uncommon among patients undergoing TAVR. - Patients more likely to have hemoglobin drop without bleeding include those with lower body surface area, older age, and higher pre-procedural hemoglobin level. - Compared to patients without bleeding or hemoglobin drop, patients with hemoglobin drop without bleeding had higher inpatient mortality. - Blood transfusion increased short-and long-term mortality in patients with or without bleeding. Visual Abstract