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Hypertension in cats with chronic renal failure or hyperthyroidism
D L Kobayashi1, M E Peterson, T K Graves
1Animal Medical Center, New York, NY 10021.
Insights
Hypertension is common in cats with kidney failure or hyperthyroidism. Blood pressure often normalizes in hyperthyroid cats after successful treatment, indicating reversible hypertension.
Area of Science:
- Veterinary Medicine
- Cardiology
- Nephrology
Background:
- Hypertension is a recognized complication in feline medicine.
- Both chronic renal failure and hyperthyroidism are conditions associated with elevated blood pressure in cats.
Purpose of the Study:
- To investigate the prevalence of hypertension in cats with naturally occurring renal failure and hyperthyroidism.
- To compare blood pressure measurements in affected cats to those of clinically normal cats.
- To assess the reversibility of hypertension in hyperthyroid cats following treatment.
Main Methods:
- Doppler ultrasonic technique used for indirect measurement of systolic and diastolic blood pressures.
- Study included 28 cats with renal failure, 39 with hyperthyroidism, and 33 normal cats.
- Blood pressure was re-evaluated in a subset of treated hyperthyroid cats.
Main Results:
- Cats with renal failure showed significantly higher systolic (146.6 mmHg) and diastolic (96.6 mmHg) pressures than normal cats (118.4/83.8 mmHg).
- Hyperthyroid cats exhibited significantly higher systolic (167.9 mmHg) and diastolic (111.6 mmHg) pressures compared to normal cats.
- Hypertension was present in 61% of renal failure cats and 87% of hyperthyroid cats.
- Successful treatment of hyperthyroidism led to a significant decrease in systolic blood pressure.
Conclusions:
- Mild to moderate hypertension is prevalent in cats suffering from chronic renal failure.
- Untreated hyperthyroidism is frequently associated with significant hypertension in cats.
- Hypertension in hyperthyroid cats appears to be reversible after effective treatment of the underlying condition.
Abstract:
The Doppler ultrasonic recording technique was used to measure systolic and diastolic blood pressures indirectly in 28 cats with naturally occurring renal failure, 39 cats with hyperthyroidism, and 33 clinically normal cats. The mean systolic and diastolic blood pressures in the normal cats were 118.4 +/- 10.6 mm Hg and 83.8 +/- 12.2 mm Hg, respectively. In the cats with chronic renal failure, both the systolic (146.6 +/- 25.4 mm Hg) and diastolic (96.6 +/- 15.2 mm Hg) blood pressures were significantly higher (P less than 0.0001 and P less than 0.01, respectively) than in the normal cats. Elevations in systolic and/or diastolic blood pressure were recorded in 17 (61%) of the 28 cats with chronic renal failure. In the 39 untreated hyperthyroid cats, both the mean systolic (167.9 +/- 28.9 mm Hg) and diastolic (111.6 +/- 21.5 mm Hg) pressures also were significantly higher (P less than 0.0001) than normal. Increased systolic and/or diastolic blood pressure was recorded in 34 (87%) of the 39 hyperthyroid cats. In seven cats with hyperthyroidism that were reevaluated two to four months after successful treatment of the hyperthyroid state, there was a significant fall in mean systolic pressure (P less than 0.05) from a pretreatment value of 159.5 +/- 15.4 mm Hg to a posttreatment value of 132.0 +/- 1.62 mm Hg. Overall, the results of this study indicate that mild to moderate hypertension is common in cats with chronic renal failure and in cats with untreated hyperthyroidism. In addition, the hypertension appears to be reversible following successful treatment of the hyperthyroid state.