1Universitätsklinikum Würzburg Medizinische Klinik und Poliklinik I Würzburg, Deutschland
Background
Kidney insufficiency with anaemia is associated with poor outcome of aortic stenosis patients underwent transcatheter aortic valve implantation (TAVI). Present study aimed to investigate the association of kidney function and anaemia with two-year outcome in TAVI patients with preserved kidney function.
Methods
We screened 1275 severe aortic stenosis patients who underwent TAVI in our hospital between July 2009 and December 2021. Serum creatinine, estimated glomerular filtration rate using MDRD formula (eGFR), and haemoglobin (Hb) results were reviewed. Hb<12g/dl in female and Hb<14g/dl in male was defined as anaemia. TAVI patients with a preserved kidney function (eGFR >60 ml/min/1.73m², n=534, 80.7±5.6 years, 60.1% male) before procedure were included for the further analysis. All patients completed a 2-year clinical follow up after TAVI. The primary endpoint was defined as all-cause mortality.
Results
Median EuroSCORE II was 3.09 (2.00-5.19)%. Median eGFR was 73 (65-83) ml/min/1.73m², median Hb was 12.8 (11.8-1.08) g/dl. All-cause mortality was 13.9% (74/534) at two years after TAVI, and was significantly higher in TAVI patients with anaemia than those without anaemia (17.5% vs. 8.7%, P=0.003). All-cause mortality was significantly higher in patients with an eGFR of >90 ml/min/1.73m² compared to those with an eGFR of 60-90ml/min/1.73m² (20.7% vs. 12.6%, P=0.049). Patients with anaemia and an eGFR of >90 ml/min/1.73m² presented with higher all-cause mortality (14/49, 28.6%) than those with anaemia and an eGFR of 60-90 ml/min/1.73m² (41/266, 15.4%, P=0.026).
Based on these findings, eGFR/Hb ratio was used to predict all-cause mortality of TAVI patients with preserved kidney function. Mean eGFR/Hb ratio was 6.14±1.65, and significantly higher in the non-survivors than in the survivors (7.08±2.90 vs. 5.99±1.29, hazard ratio 1.233, 95% CI 1.153-1.318, P<0.001). Patients were then categorized into 3 risk groups according to the eGFR/Hb ratio: low risk group, ≤6.5, n=379; intermediate risk group, 6.6-7.9, n=104; high risk group, ≥8.0, n=51. All-cause mortality was increased in proportion to the increase of eGFR/Hb ratio (10.3% vs. 17.3% vs. 33.3% in the low-, intermediate-, and high-risk groups, P<0.001). Compared with low-risk TAVI patients, intermediate-risk and high-risk patients were associated with about 2-fold (HR=2.234, 95% CI 1.256-3.974, P=0.006) and 4-fold (HR=4.752, 95% CI 2.619-8.624, P<0.001) increased risk of all-cause mortality at 2 years after TAVI, irrespective of age, EuroSCORE II, and atrial fibrillation.
Conclusions
The novel eGFR/Hb ratio might serve as a simple and feasible predictor for two-year all-cause mortality in TAVI patients with preserved kidney function, irrespective of age, EuroSCORE II and atrial fibrillation.