Red blood cell distribution width as a prognostic factor in patients undergoing transcatheter aortic valve implantation

Background: Red blood cell distribution width (RDW), which is routinely reported in complete blood counts, is a measure of the variability in size of circulating erythrocytes. RDW is an independent predictor of prognosis in patients with cardiovascular diseases. We evaluated the short- and long-term prognostic value of RDW in a large cohort of transcatheter aortic valve implantation (TAVI) patients. Methods: The impact of RDW on outcome was determined prospectively in 1029 consecutive patients with severe aortic stenosis (AS) undergoing transfemoral TAVI. The cohort was divided into 2 groups according to RDW above and below 15.5%. Collected data included patient characteristics, medical background, left ventricle ejection fraction (LVEF), frailty score, Society of Thoracic Surgeons (STS) score, periprocedural laboratory results, and long-term (up to 7.5 years) clinical outcomes. Results: The mean age (±SD) was 83.1 ± 6.3 years, mean STS score was 4.2 ± 3.1% and mean estimated LVEF was 55.7 ± 8.4%. Mean pre-TAVI RDW levels were 15.3 ± 3.2%. Patients with RDW ≤ 15.5% (n = 683) and RDW > 15.5% (n = 346) had a 1-year mortality rate of 6% and 17%, respectively (p = 0.001) and a 5-year mortality rate of 20% and 38%, respectively (p < 0.001). Baseline RDW > 15.5% was independently associated with all-cause mortality (hazard ratio 1.83, 95% confidence interval 1.44–2.32, p < 0.001). Conclusions: Elevated RDW is a strong independent marker and predictor of short- and long-term mortality following TAVI, that might present a relevant future supplement to current preprocedural risk scores. Additional research is needed to clarify the mechanisms responsible for this finding.