Diagnostic Value of Renography for Detection of Unilateral Renal or Renovascular Disease in Hypertensive Patients

Abstract

In an effort to find an optimal set of renographic reference parameters for the study of hypertensive patients, the renographic data from 50 hypertensive patients with unilateral renal or renovascular disease were assessed against 95% confidence intervals obtained in normal subjects and in patients with essential hypertension in two different states of hydration. The highest all-over nosographic sensitivity and specificity were obtained by using the data from hydrated normal subjects as reference parameters. The nosographic sensitivity and specificity found in the selected series of hypertensive patients were converted to the clinically relevant predictive values of a positive and a negative test by assuming the prevalence of unilateral renal or renovascular disease in hospital populations of hypertensive patients to be 5% or 10%. In these model populations the predictive value of a positive test was 33% and 51%, respectively. The predictive value of a negative test was higher than 99% for both populations. We find that predictive values of that order of magnitude are satisfactory for a test to be used in the initial phase of a diagnostic process.

Key Words:

• Hypertension
• predictive values of a positive and negative renogram
• renography
• unilateral renal artery disease
• unilateral contracted kidney