Mild impairment of renal function (shrunken pore syndrome) is associated with increased risk for future surgery for aortic stenosis

Abstract

Recently, a new approach was proposed to detect mild impairment in renal function: a reduced ratio between estimated glomerular filtration rate (eGFR) calculated by cystatin C and eGFR calculated by creatinine. We aimed to evaluate if this ratio is associated with aortic stenosis (AS) requiring surgery. We identified 336 patients that first participated in population surveys and later underwent surgery for AS (median age [interquartile range] 59.8 [10.3] years at survey and 68.3 [12.7] at surgery, 48% females). For each patient, two matched referents were allocated. Cystatin C and creatinine were determined in stored plasma. eGFR_{cystatin C} and eGFR_creatinine and their ratio were estimated. Conditional logistic regression analyses were used to estimate the risk (odds ratio (OR) with [95% confidence interval (CI)]) related to one (ln) standard deviation increase in the ratio between eGFR_{cystatin C} and eGFR_creatinine. A high ratio was associated with lower risk for AS requiring surgery (OR [95% CI]) (OR 0.84 [0.73–0.97]), especially in women (0.74 [0.60–0.92] vs. 0.93 [0.76–1.13] in men). After further stratification for coronary artery disease (CAD), the association remained in women with CAD but not in women without CAD (0.60 [0.44–0.83] and 0.89 [0.65–1.23], respectively). In conclusion, a high ratio between eGFR_{cystatin C} and eGFR_creatinine was associated with lower risk for surgery for AS, especially in women. Mild impairment of renal function is thus associated with future risk for AS requiring surgery.

Keywords:

• Aortic stenosis
• valvular replacement
• renal insufficiency
• creatinine
• cystatin C

Acknowledgements

The authors wish to acknowledge the Västerbotten Intervention Project (VIP), the Northern Sweden MONICA project, the Northern Sweden Health and Disease Study, the County Council of Västerbotten and Biobank Sweden. We also appreciate the assistance provided by Elin Albersson, Kerstin Enquist, Göran Hallmans, Veronica Hellström, Jan Henschel, Paul Holmer, Catrin Johansson, Camilla Ring, Mattias Söderberg and Åsa Ågren – all of whom have been instrumental in the completion of this study. We also appreciate the assistance provided by Eva Samuelsson and the staff at Clinical Chemistry, Laboratory Medicine, Umeå University Hospital Umeå.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability

The datasets generated during the current study are not publicly available as the dataset contains identifiable patient data but are available from the corresponding author on reasonable request.

Additional information

Funding

This work was supported by the Swedish Heart-Lung Foundation [grant numbers 20140799, 20120631 and 20100635], The County Council of Västerbotten (ALF VLL-548791), Umeå University and The Heart Foundation of Northern Sweden. This work was also supported by the Swedish Research Council (VR 2017-00650).