FGF23 is a novel risk factor for patients undergoing TAVR

Valvular heart disease is a leading cause of cardiovascular morbidity. Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure that replaces the aortic valve in patients with aortic stenosis.  Mineral homeostasis, the process that regulates the body’s levels of calcium and phosphorus, plays an important role in the progression of cardiovascular diseases, including calcific aortic valve stenosis. FGF23 is a bone-derived phosphotropic hormone that regulates phosphate and vitamin D metabolism. FGF23 has been shown to be an independent risk factor for CV morbidity and mortality.

FGF23 is a novel risk factor for patients undergoing TAVR

A study by Mirna et al. evaluated the predictive potential of both C-terminal FGF23 (cFGF23) and intact FGF23 (iFGF23) for adverse outcomes in patients undergoing transcatheter aortic valve replacement (TAVR) with regard to renal function. Patients were followed up at 12 months.

The authors demonstrated:

• significant association of high cFGF23 levels with mortality in patients with an estimated glomerular filtration rate (eGFR) ≥45 ml/min/1.73m².
• patients with cFGF23 levels above the cut-off of 6.82 pmol/l had a worse 1-year-mortality
• cFGF23 could be a novel risk factor for patients undergoing TAVR with eGFR ≥45ml/min/1.73m².

 

FGF23 (C-terminal) and FGF23 intact were both measured with an ELISA assay from BIOMEDICA.

 

Assay Highlights

• full validation package
• for serum and plasma
• +50 international references

 

LITERATURE

Serum levels of C-terminal FGF23 (cFGF23) are associated with 1-year-mortality in patients undergoing transcatheter aortic valve replacement (TAVR).

Mirna M, Lauten A, Jirak P, Rezar R, Wernly B, Paar V, Felder TK, Hoppe UC, Motloch LJ, Jung C, Alushi B, Lichtenauer M, Salmhofer H. Eur J Intern Med. 2021. 85:98-107. doi: 10.1016/j.ejim.2020.09.022. Epub 2020 Nov 13. PMID: 33191056.

Abstract

Introduction: Serum levels of FGF23 have been associated with adverse outcomes in cardiovascular diseases in patients with and without impaired renal function. Hence, this study aimed to explore the prognostic relevance of intact FGF23 (iFGF23) and its derivate C-terminal FGF23 (cFGF23) in patients undergoing transcatheter aortic valve replacement (TAVR) with regard to renal function.

Methods: A total of 274 patients undergoing transfemoral TAVR were enrolled in this study. Blood samples were obtained preinterventionally and analyzed for iFGF23 and cFGF23 by means of enzyme linked immunosorbent assay (ELISA). Follow-up was obtained for 12 months.

Results: Serum levels of cFGF23 and iFGF23 both correlated positively with serum creatinine and inversely with estimated glomerular filtration rate (eGFR). Cox regression analysis revealed a significant association of cFGF23 with 1-year-mortality in patients with eGFR ≥45ml/min/1.73m², but not in patients with an eGFR <45ml/min/1.73m². A cut-off was calculated for cFGF23 (6.82 pmol/l) and patients with eGFR ≥45ml/min/1.73m² were retrospectively divided into two groups (above/below cut-off). Patients above the cut-off had a significantly worse 1-year-mortality than patients below the cut-off (33.3% vs. 19.6%; OR 2.05 (95%CI 1.03-4.07), p= 0.038). The association of cFGF23 with 1-year-mortality in patients with eGFR ≥45ml/min/1.73m² remained statistically significant even after correction for possible confounders in a multivariate Cox regression analysis.

Conclusion: cFGF23 could be an individual risk factor for mortality in patients undergoing TAVR with an eGFR ≥45ml/min/1.73m².