Objective To investigate the prognostic value of baseline and temporal changes in red cell distribution width (RDW) in patients undergoing transcatheter aortic valve implantation (TAVI).

Design Single-centre retrospective observational study.

Setting Tertiary cardiac centre.

Patients 175 patients undergoing TAVI were included in this study.

Main outcome measure Survival.

Results We analysed data from 175 TAVI patients (mean (±SD) age 83±7 years, 49% men, mean Logistic EuroSCORE 23±1, 66% preserved left ventricular ejection fraction (LVEF)). Immediately pre-TAVI, mean RDW was 14.6±1.6% with an RDW>15% in 29% of patients. Over median follow-up of 12 months, the median rate of change in RDW was 0.2% per month, and 51 (29%) patients died. On multivariate survival analyses, baseline RDW≥15.5% predicted death (adjusted HR 2.70, 95% CI 1.40 to 5.22, p=0.003) independently of LVEF, transfemoral approach, baseline pulmonary artery systolic pressure, moderate/severe mitral regurgitation and body mass index. A greater rate of increase in RDW over time was associated with increased mortality (adjusted HR 1.11, 95% CI 1.04 to 1.18, p=0.001) independently of baseline RDW and other significant temporal variables including a change in creatinine, bilirubin, mean cell haemoglobin concentration or urea. An increase in RDW>0.1%/month was associated with a twofold increased risk of mortality.

Conclusions Baseline RDW≥15.5% and a rising RDW over time strongly correlate to an increased risk of death post-TAVI, and could be used to refine risk stratification. Investigating and ameliorating the causes of RDW expansion may improve survival.