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Captopril renal scintigraphy in patients with hypertension and chronic renal failure
I E Datseris1, J B Bomanji, E A Brown
1Department of Nuclear Medicine, St. Bartholomew's Hospital, London, England, UK.
Insights
Captopril renography effectively identifies angiotensin II-dependent renovascular disorder in hypertensive patients with chronic renal failure. This imaging technique may also predict beneficial effects of angiotensin-converting enzyme (ACE) inhibitor therapy on renal function.
Area of Science:
- Nephrology
- Radiology
- Hypertension
Background:
- Hypertension and chronic renal failure often involve angiotensin II-dependent renovascular disorder.
- Accurate diagnosis is crucial for effective treatment with angiotensin-converting enzyme (ACE) inhibitors.
Purpose of the Study:
- To evaluate captopril renography's ability to detect angiotensin II-dependent renovascular disorder in hypertensive patients with chronic renal failure.
- To assess the predictive value of captopril renography for beneficial ACE inhibitor therapy.
Main Methods:
- Prospective study involving 41 hypertensive patients with chronic renal failure.
- Renal scintigraphy performed with 99mTc-mercaptoacetyltriglycine (MAG3) before and after captopril administration.
- Patients categorized by probability of renal artery stenosis (RAS) based on established criteria.
Main Results:
- Captopril renography identified high probability of RAS in 7 patients, confirmed angiographically in 5.
- Scintigraphic parameters were nonspecific in patients with severe renal impairment (GFR ≤ 10 ml/min/1.73 m2 or split renal function ≤ 10%).
- Mean parenchymal transit time predicted beneficial ACE inhibitor therapy in 23 patients.
Conclusions:
- Captopril renal scintigraphy is valuable for identifying angiotensin II-dependent renal dysfunction in hypertensive patients with renal failure.
- The technique may aid in predicting the therapeutic response to ACE inhibitors.
Unlabelled:
The aim of this prospective study was to determine the ability of the captopril renogram to reveal the presence of angiotensin II-dependent renovascular disorder in hypertensive patients with chronic renal failure and to assess the possibility of predicting beneficial effect of angiotensin-converting enzyme (ACE) inhibitors on renal function.
Methods:
Forty-one patients were evaluated. Baseline renal scintigraphy was performed with 80 MBq of 99mTc-mercaptoacetyltriglycine (MAG3) injected intravenously. Scintigraphy was repeated within a week with 25 mg of oral captopril given 60 min prior to the test. Using the measurements outlined by the Working Party on Diagnostic Criteria of Renovascular Hypertension with Captopril Renography, the patients were categorized into high (7 patients), indeterminate (19 patients) and low (15 patients) probability for renal artery stenosis (RAS).
Results:
In five of the seven patients with high probability, the presence of RAS was confirmed angiographically and corrective surgical procedure performed in two. In patients with GFR of 10 ml/min/1.73 m2 and/or split renal function of 10% or less, all qualitative and semiquantitative scintigraphic parameters were nonspecific. Mean parenchymal transit time of tracer was a useful parameter to predict the beneficial effect of ACE inhibition therapy in 23 patients (14 low and 9 indeterminate probability of RAS).
Conclusion:
In hypertensive patients with renal failure, captopril renal scintigraphy can be utilized to identify the presence of angiotensin II-dependent renal dysfunction and possibly help to predict the beneficial effect of ACE inhibitor therapy.