Results of this study were presented at BSAVA Congress 2011, Birmingham, UK
Renin-Angiotensin-Aldosterone System Activity in Hyperthyroid Cats with and without Concurrent Hypertension
Article first published online: 20 MAR 2013
Copyright © 2013 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 27, Issue 3, pages 522–529, May/June 2013
How to Cite
Williams, T.L., Elliott, J. and Syme, H.M. (2013), Renin-Angiotensin-Aldosterone System Activity in Hyperthyroid Cats with and without Concurrent Hypertension. Journal of Veterinary Internal Medicine, 27: 522–529. doi: 10.1111/jvim.12062
- Issue published online: 9 MAY 2013
- Article first published online: 20 MAR 2013
- Manuscript Accepted: 28 JAN 2013
- Manuscript Revised: 8 JAN 2013
- Manuscript Received: 11 SEP 2012
- Aldosterone:renin ratio;
- Blood pressure;
- Plasma renin activity
Hypertension is present in some hyperthyroid cats at diagnosis or can develop after treatment for hyperthyroidism. Activation of the renin-angiotensin-aldosterone system (RAAS) could be involved in the pathogenesis of hypertension.
Hyperthyroid cats that develop hypertension before or after treatment for hyperthyroidism will have greater RAAS activation than normotensive cats.
Ninety-nine hyperthyroid cats.
Retrospective case–control study. Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured in untreated hyperthyroid hypertensive cats (HT-Pre group), initially normotensive hyperthyroid cats that develop hypertension after treatment (HT-Post group), and hyperthyroid cats that are normotensive (NT group). Data are presented as median [25th, 75th percentile].
Baseline PRA was not significantly different among the 3 groups (HT-Pre group 1.50 [0.05, 2.37] ng/mL/h, HT-Post group 0.66 [0.17, 2.31] ng/mL/h, NT group 1.11 [0.57, 2.18] ng/mL/h; P = .44). PRA decreased significantly after treatment in the NT group (1.09 [0.53, 2.47] versus 0.22 [0.05, 0.76] ng/mL/h; P < .001) and the HT-Post group (0.71 [0.17, 2.33] versus 0.28 [0.07, 0.57] ng/mL/h; P = .006). Baseline PAC was not significantly different among the 3 groups (HT-Pre group 72.2 [40.0, 145.6] pg/mL, HT-Post group 69.7 [43.3, 142.6] pg/mL, NT group 109.0 [68.2, 184.6] pg/mL; P = .10). PAC decreased significantly after treatment in the NT group (114.4 [56.6, 204.1] versus 59.5 [32.4, 98.2] pg/mL; P < .001) but did not change significantly in the HT-Post group (61.2 [44.9, 124.0] versus 58.4 [42.0, 97.7] pg/mL; P = .59).
Conclusions and Clinical Importance
RAAS activation occurs in hyperthyroid cats, but is not associated with the development of hypertension. PAC is not influenced by changes in PRA in hyperthyroid cats that develop hypertension after treatment, perhaps indicating RAAS dysfunction in these cats.