Reevaluating the lower limit of renal autoregulation: does one size fit all?

Renal autoregulation plays a crucial role in maintaining stable renal blood flow despite fluctuations in systemic arterial pressure. Existing paradigms, largely based on animal studies, suggest an autoregulation lower limit of 80 mmHg. However, the direct applicability of these findings to human physiology and clinical practice remains uncertain. Accordingly performed a comprehensive literature review to reevaluate the evidence about the lower limit of renal autoregulation. Animal and human studies were identified to assess the variability of the lower limit of renal autoregulation across different species, the influence of chronic conditions and acute interventions on this threshold, and the impact of blood pressure management strategies in critical care and anesthesia settings. We identified a broad range of lower limits of renal autoregulation, which were significantly influenced by experimental conditions and species differences. Human studies suggest that the autoregulation threshold might be lower than the traditionally mentioned 80 mmHg, with evidence indicating that renal function can be preserved at <80 mmHg mean arterial pressure levels. Moreover, clinical trials did not document a deterioration in renal function with blood pressure targets <80 mmHg. In individuals with diabetes, hypertension, or renal insufficiency the lower limit of autoregulation was increased. In humans there is insufficient evidence to state that 80 mmHg is the lower limit of renal autoregulation. This 80 mmHg threshold was also inconsistently identified in dog and mouse studies. Some human disease, however, may alter the limits of such autoregulation. Further research is warranted to define the value of the autoregulation threshold in human disease.