Differential effects of anaemia and iron deficiency on long-term outcomes following transcatheter edge-to-edge repair in degenerative vs. secondary mitral regurgitation: results from a large single-center study

BACKGROUND: Anaemia and iron deficiency (ID) are independently associated with adverse outcomes in patients with cardiovascular diseases, especially in those with heart failure. Here, we aimed to clarify the long-term effect of anaemia and ID on outcomes in patients undergoing transcatheter mitral edge-to-edge repair (TEER) for relevant mitral regurgitation (MR) as well as to relate these to the underlying MR aetiology.

METHODS: 833 patients (median age 77.1 years, 40.7% women, 63.3% secondary MR) treated by TEER between 09/2008 and 07/2019 were included and stratified according to baseline anaemia (hemoglobin < 12 g/dL in women and < 13 g/dL in men) or ID.

RESULTS: Anaemia and ID were frequent with 61.6% and 68.1%, respectively. Anaemic patients had a lower functional status at baseline and were less likely to improve after TEER. In addition, anaemia was associated with all-cause mortality (hazard ratio [HR] = 1.68, 95% confidence interval [CI] 1.36-2.07, p < 0.001) and the composite endpoint of death or heart failure (HF) rehospitalization (HR = 1.30, 95% CI 1.10-1.54, p = 0.002). In contrast, ID was not associated with either all-cause mortality or the composite endpoint of death or HF rehospitalization.

CONCLUSION: Patients undergoing TEER have high rates of both anaemia and ID. However, anaemia is associated with worse functional baseline status and post-interventional improvements compared to ID. Furthermore, anaemia is linked to higher rates of mortality and HF rehospitalization, particularly in those with secondary MR.