Response to Renal Sympathetic Denervation: Renal Function Concerns
We thank Petidis et al1 for drawing attention to the importance of the renal function aspects of renal sympathetic denervation. As we alluded to in our article and as the authors have reinforced, there was some loss of preservation of renal function beyond the formal 12-month follow-up time period of the Symplicity HTN-1 Study.2 During the first 12 months, changes in antihypertensive medication were discouraged. Beyond this time, however, liberalization of concomitant medication use appears to have occurred, especially increased use of spironolactone and other diuretics. In this regard, diuretic sensitivity may have been enhanced by the denervation procedure, leading to prerenal azotemia.
With regard to the magnitude of reduction in estimated glomerular filtration rate, these patients start with very high blood pressure levels that were lowered by the denervation procedure, but still, in most cases, blood pressure remained in the hypertensive range (baseline systolic blood pressure mean of 176 mm Hg, end study systolic blood pressure mean of 144 mm Hg). Bakris et al3 have shown that deterioration in renal function over time is linearly related to blood pressure control. The magnitude of that deterioration over the first 12 months is less in our cohort than that expected from the retrospective relationship generated by Bakris et al.3 In the patients who completed the 2 years and did not have diuretic-type medications added, the reduction in estimated glomerular filtration rate over time was roughly consistent with (if not slightly better than) what would be expected given their degree of blood pressure control. We strongly agree with the authors that careful evaluation of renal hemodynamics is required as part of the ongoing evaluation of the renal denervation procedure.
Centre of Cardiovascular Research and Education in
School of Public Health and Preventive Medicine
Melbourne, Victoria, Australia
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- © 2011 American Heart Association, Inc.
- Petidis K,
- Anyfanti P,
- Doumas M
Symplicity HTN-1 Investigators. Catheter-based renal sympathetic denervation for resistant hypertension: durability of blood pressure reduction out to 24 months. Hypertension. 2011; 57: 911– 917.
- Bakris GL,
- Williams M,
- Dworkin L,
- Elliott WJ,
- Epstein M,
- Toto R,
- Tuttle K,
- Douglas J,
- Hsueh W,
- Sowers J