Abstract: FR-PO567

Renal Functional Reserve Is Related to Exercise Heart Rate in Essential Hypertensive Patients: A Novel Link between the Kidneys and the Heart

Session Information

Category: Hypertension

  • 1102 Hypertension: Basic and Experimental - Renal Causes and Consequences

Authors

  • Damianaki, Aikaterini, Hippokration Hospital , ATHENS, Greece
  • Dimitriadis, Kyriakos, First Cardiology Clinic, University of Athens, Hippokration Hospital, Athens, Greece
  • Chalkia, Aglaia, Hippokration Hospital , ATHENS, Greece
  • Tsioufis, Konstantinos, First Cardiology Clinic, University of Athens, Hippokration Hospital, Athens, Greece
  • Petras, Dimitrios, Hippokration Hospital , ATHENS, Greece
Background

Renal functional reserve (RFR) refers to the capacity of the kidney to augment its level of function under the influence of certain stimuli and it constitutes a valuable diagnostic tool for recognizing high risk patients for acute kidney injury (AKI) and chronic kidney disease (CKD). The aim of our study was to assess the relation of RFR with diverse clinical parameters in patients with essential hypertension and GFR>60ml/min/1.73m2.

Methods

15 hypertensive subjects (mean age=57 years, BMI= 28.5 kg/m2, office systolic/diastolic BP =148/90 mmHg) were included. All subjects underwent the exercise treadmill stress test, 24hour ABPM and cardiac ultrasound. Subjects who were on antihypertensive medication, stopped the agents for two weeks. All subjects were fasted for 8 hours and then baseline hydration status was recorded using bioimpedance analysis. Basal GFR was measured after hydration and stress GFR was achieved after ingestion of oral protein 1g/kg as cooked meal. Basal and Stress GFR were determined by Creatinine Clearance = Urine Creatinine/Serum CreatininexUrine Volume/time× 1.73/BSA). RFR was calculated as Stress GFR – Basal GFR.

Results

Patients with greater than 10years of HTN, had lower RFR values (p<0.1) (-14.59 ±43.26 ml/min/1.73m2 vs 21.35±28.19 ml/min/1.73m2). There was no correlation of RFR values with respect to family history, smoking, BMI, age, dipping and office BP. In contrast, a statistically significant positive correlation was found between RFR and maximum heart rate (HR) during treadmill test (r=0.880, p=0.009). Hypertensives with high RFR were characterized by higher maximum HR during treadmill test.

Conclusion

RFR is related to treadmill exercise heart rate in essential hypertension, suggesting a link between the dynamic regulation of renal function and sympathetic overdrive influence on the heart. These findings suggest that treadmill test could be used to identify hypertensive patients with unfavorable RFR. Additionally, patients with greater than 10 years of HTN and/or on antihypertensive agents tend to have lower RFR values, indicating a possible susceptibility to renal injury.