Impact 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
Authors: Khurrami S , Koell B , Ludwig S , Pauschinger C , Weimann J , Reichenspurner H , Conradi L , Schaefer A , Blankenberg S , Lubos E , Schofer N , Kalbacher D 
Published: November 2023

Abstract

Background
Transcatheter mitral valve edge-to-edge repair (TEER) is an established therapeutic option for significant mitral regurgitation (MR), as an alternative for patients at high risk for open heart surgery. While mitral valve reconstruction is the guideline-recommended treatment modality for degenerative mitral regurgitation (DMR), secondary mitral regurgitation (SMR) is more complex and requires a multifaceted approach. Anaemia and iron deficiency (ID) are both associated with unfavourable outcomes in patients with cardiovascular diseases, particularly in those with heart failure. In patients undergoing TEER, the prevalence of ID and anaemia is exceptionally high. However, data regarding the impact of anaemia and ID on outcomes are limited to short- and mid-term follow-up periods.

Purpose
This retrospective single center study, aimed to investigate effects of anaemia and ID on long-term outcomes following TEER for relevant MR, as well as to relate it to the underlying MR aetiology.

Methods
A total of 833 patients (mean age 76.1 ± 8.4 years, 40.7% female, 63.3% secondary MR) were treated by TEER between September 2008 and July 2019. Patients were stratified based on their anaemia status (anaemia was defined as hemoglobin &lt;12 g/dL in females and &lt;13 g/dL in males) or ID (defined according to current HF guidelines as a serum ferritin concentration of &lt;100 ng/mL or 100–299 ng/mL and a transferrin saturation &lt;20%). Clinical follow-up was conducted primarily through in-person visits or by structured telephone interviews at 6 and 12 months after intervention and annually thereafter. The median follow-up time was 5.5 years, with a maximum follow-up of 12.3 years.

Results
Anaemia and ID were prevalent among patients with 61.6% and 68.1%, respectively. Among all anaemic patients, 73.5% also had ID. Anaemic patients had a lower functional status at baseline and were less likely to show improvement after TEER. Additionally, anaemia was significantly associated with all-cause mortality (hazard ratio [HR]=1.68, 95%-confidence interval [CI]: 1.36-2.07, p&lt;0.001) and the composite endpoint of death or heart failure rehospitalization (HR=1.30, 95%-CI: 1.10-1.54, p=0.002). Moreover, anaemia was found to be an independent predictor for all-cause mortality in patients with secondary MR, with a 5-year mortality rate of 69.9% in anaemic patients compared to 47.8% in non-anaemic patients (p&lt;0.001). However, ID was not associated with an increased risk of all-cause mortality or the composite endpoint of death or heart failure rehospitalization for either degenerative or secondary MR.

Conclusion
The high prevalence of anaemia and ID in patients undergoing TEER is noteworthy. Anaemia was associated with poorer functional baseline status and less post-interventional improvement. Furthermore, and in contrast to ID, anaemia was linked to higher mortality rates and more heart failure rehospitalizations, particularly in patients with secondary MR.Kaplan Meier survival analysisPredictors for all-cause mortality