SIGNIFICANCE OF 24-H BLOOD-PRESSURE MONIT ORING IN THE DIAGNOSIS OF RENAL-ARTERY STENOSIS COMPARED WITH COLOR-CODED DUPLEX SONOGRAPHY AND RENAL ANGIOGRAPHY

Background: Direct renal angiography is still the method of choice for identification of renal artery stenosis. Newer non-invasive diagnosti c methods include color coded duplex sonography and also ambulatory 24 -h blood pressure monitoring, since in a large proportion of patients with secondary forms of hypertension the usual blood pressure fall dur ing nighttime disappears. Patients and Methods: In a prospective in-ho spital study we investigated 86 patients with suspected renovascular h ypertension. Circadian blood pressure was measured oscillometrically a nd color coded duplex sonography was performed immediately before dire ct renal angiography. Results: Angiography revealed renal artery steno sis (greater than or equal to 50%) in 42 patients. This compared to a sensitivity of 92.9% and specifity of 91.7% for the use of sonography in those patients (70.4%) who could be adequately examined. Mean 24-h pressure values as well as standard deviations of blood pressure means as an indicator for blood pressure variability were not different in the 2 groups of patients, when all the data were analysed together and also when the data for nighttime and daytime were examined separately . The percent of blood pressure fall during nighttime was also not dif ferent in the 2 groups. In both groups 4 hypertensive patients had a b lood pressure increase during nighttime. In 11 patients without renal artery stenosis a blood pressure fall of < 10% was observed, compared to 12 patients with renal artery stenosis. The circadian pattern of pu lse rate was similar in both groups. Conclusion: We conclude that ambu latory blood pressure monitoring has a considerably lower diagnostic v alue for renal artery stenosis compared to angiography and also to col or coded duplex sonography. This method therefore does not appear to b e an appropriate screening approach for this kind of secondary hyperte nsion. The color coded duplex sonography, however, seems to be the bes t non-invasive diagnostic method in those patients, who can be adequat ely examined.