To evaluate the validity as a screening test for identifying renovascular hypertension and other secondary hypertension, the blood pressure and responses of plasma renin activity and plasma aldosterone to oral test dose (25 mg) of captopril were studied in the 36 patients clinically suspected for renovascular hypertension.
The results obtained were as follows:
1) Among the 36 patients, 18 were with renovascular hypertension (the 10 were due to Takayasu´s arteritis), 8 with chronic renal failure, 6 with primary aldosteronism (all due to adrenal cortical adenoma), and 4 without any other secondary cause.
2) The reduction of systolic and diastolic pressure at the 90 minutes after captopril was significant in the patients with renovascular hypertension and chronic renal failure (p<0.05).
3) The basal and stimulated plasma renin activities, absolute increase in plasma renin activity after captopril, and the ratio of postcaptopril to precaptopril plasma renin activity were significantly high in the patients with renovascular hypertension (p<0.01).
4) The ratio of basal plasma aldosterone to renin activity, plasma aldostone at the 90 minutes after captoril and the ratio of postcaptopril plasma aldosterone to postcaptoril renin activity were significantly high in the patients with primary aldosteronism (p<0.01).
5) The 3 criteria those mean the hyperresponsiveness of renin secretion in the diagnosis of renovascular hypertension could discriminate from the other causes of hypertension, and the ratio of postcaptopril plasma aldosterone to postcaptopril renin activity could discriminated the patients with primary aldosteronism from the other causes.
Thus we concluded that oral test of captopril may be a useful screening test for the diagnosis of the renovascular hypertension, and since the test also characterizes the renin and aldosterone dependency of the hypertension, it may have other diagnositc and therapeutic uses.
|