Anaemia and mortality in patients with transcatheter aortic valve replacement: a systematic review and meta-analysis

Objective: This study was done to determine the relationship between pre-procedural anaemia and mortality post transcatheter aortic valve replacement (TAVR). Introduction: TAVR is now a treatment option for patients with severe aortic stenosis (AS) with high surgical risk. Anaemia is a common comorbidity in the TAVR population. Small studies have suggested that anaemia is associated with worse short-term and long-term mortality in patients who underwent TAVR. However, there are no meta-analyses to further assess this association. Method: Studies were systematically searched from electronic databases (EMBASE and MEDLINE). Inclusion criteria were adult population with aortic stenosis who underwent TAVR, and number of patients with pre-procedural anaemia reported. Outcomes were short-term mortality or long-term mortality. Pooled effect size was calculated with a random-effect model, weighted for the inverse of variance. Heterogeneity was assessed with I². Results: Six studies were included in the final analysis. Of these, pooled analysis of four studies examining association between anaemia and 30-day mortality did not show a statistically significant relationship. A pooled analysis of four studies examining the association of anaemia and long-term mortality after TAVR showed pooled adjusted risk ratio (RR) of 1.43, 95% CI 1.22-1.67 with low heterogeneity (I² = 33%). Subgroup analysis after exclusion of one smaller study showed that the association remained significant (RR 1.41, 95% CI 1.27-1.56) with decreased heterogeneity (I² = 0%). Conclusion: This systematic review and meta-analysis found an association between pre-procedural anaemia and increased long-term but not short-term mortality after TAVR. Further study of the pathophysiology underlying this association is needed.