Abstract: FR-PO1224
Minimizing Data Requirements for Classification of Renal Autoregulation Using Short-Segment Autoregulation Index Analysis
Session Information
- CKD: Mechanisms, AKI, and Beyond - 2
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2303 CKD (Non-Dialysis): Mechanisms
Authors
- Williamson, Geoffrey A., Illinois Institute of Technology, Chicago, Illinois, United States
- Chopde, Purva R., Illinois Institute of Technology, Chicago, Illinois, United States
- Polichnowski, Aaron J., East Tennessee State University James H Quillen College of Medicine, Johnson City, Tennessee, United States
- Griffin, Karen A., Loyola University Chicago Stritch School of Medicine, Chicago, Illinois, United States
Background
Renal autoregulation (AR) denotes the ability to regulate renal blood flow, thus maintaining a stable glomerular filtration rate and protecting glomeruli from hypertensive injury. Assessing the efficiency of AR can inform management strategies related to chronic kidney disease. The Short Segment AR Index (SSARI) method is effective for evaluating AR efficiency using blood pressure (BP) and renal blood flow (RBF) measurements in conscious rats (Bidani et al., JASN 31(2):324-336, 2020). The impact of SSARI analysis parameter values on data requirements necessary to observe statistically significant differences in mean SSARI between rats with intact and impaired AR, represented by a control group of Sprague Dawley rats and a group with 5/6th nephrectomy respectively, is examined in this study.
Methods
In SSARI analysis, BP/RBF recordings are divided into short segments of varying length (e.g., 1-15 sec.), adjacent segment pairs with mean BP differences exceeding various thresholds (e.g., 1-6 mmHg) are identified, and for these pairs AR indices are calculated using ratios of fractional change in RBF and BP. The average SSARI value reflects AR efficiency. Individual SSARI mean, variance, and rate of occurrence all influence data requirements for statistical significance, and the values of these quantities depend on the threshold and segment length parameters. For a range of threshold and segment length values, data length that insures enough SSARI samples to achieve 5% significance and 80% power is determined.
Results
The figure shows recording lengths necessary for a range of thresholds and segment lengths.
Conclusion
The results provide guidance for selecting SSARI analysis parameters, suggesting a focus on shorter segment lengths and lower BP difference thresholds, as they reduce the data requirements. These findings lay the groundwork for optimizing analytical parameters that may ultimately enable assessment of renal autoregulation in patients.
Funding
- NIDDK Support