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Total and split renal function in patients with renovascular hypertension: effects of angiotensin-converting enzyme
Insights
Chronic angiotensin-converting enzyme inhibitor therapy for renovascular hypertension is safe and effective. Studies show it does not cause significant loss of kidney function, even in stenotic kidneys.
Area of Science:
- Nephrology
- Cardiology
- Pharmacology
Background:
- Renovascular hypertension is a significant cause of kidney disease.
- Angiotensin-converting enzyme inhibitors (ACEIs) are commonly used to treat this condition.
- Concerns exist regarding the safety of ACEIs in patients with renal artery stenosis.
Purpose of the Study:
- To evaluate the impact of chronic ACEI therapy on total and split renal function in patients with renovascular hypertension.
- To assess the safety and efficacy of ACEIs in this patient population.
Main Methods:
- Thirteen subjects with renovascular hypertension on chronic ACEI therapy underwent total and split renal function studies.
- Inulin clearance and p-aminohippurate clearance were used to assess total glomerular filtration rate and effective renal plasma flow.
- Radionuclide techniques were employed for split renal function assessment.
- Five patients were prospectively followed for 2 years.
Main Results:
- Total glomerular filtration rate (GFR) by inulin clearance matched radionuclide assessment.
- Total effective renal plasma flow (ERPF) by p-aminohippurate clearance was lower than radionuclide assessment.
- Radionuclide assessment showed lower GFR and ERPF in the stenotic kidney compared to the non-stenotic kidney.
- No subject exhibited complete loss of filtration or perfusion in the stenotic kidney.
- Total renal function remained stable in 5 of 6 patients over 2 years; the sixth patient showed initial decline followed by stability.
Conclusions:
- Chronic ACEI therapy does not generally lead to near-total loss of filtration in the stenotic kidney.
- ACEIs can be safely and effectively used in the management of renovascular hypertension.
- Renal function, including in stenotic kidneys, appears stable under long-term ACEI treatment.
Abstract:
Thirteen subjects with documented renovascular hypertension receiving chronic (greater than 1 month) therapy with an angiotensin-converting enzyme inhibitor (enalapril or captopril) underwent total and split renal function studies. Total glomerular filtration rate as assessed by inulin clearance was similar to that determined by radionuclide technique. Total effective renal plasma flow as assessed by p-aminohippurate clearance was lower than that determined by radionuclide technique. The glomerular filtration rate and effective renal plasma flow assessed by radionuclide technique of the stenotic kidney was comparatively lower than that of the non-stenotic kidney. No subject demonstrated complete loss of filtration or perfusion of the stenotic kidney. Five of six patients studied prospectively for 2 years have demonstrated stability of total renal function; the sixth patient, having a functional solitary stenotic kidney, has demonstrated stability of function following an initial abrupt decline in glomerular filtration rate and effective renal plasma flow. These results suggest that chronic angiotensin-converting enzyme inhibition therapy is not generally associated with near total absence of filtration of the stenotic kidney as has been suggested previously. Angiotensin-converting enzyme inhibitors may be safely and effectively utilized in the treatment of renovascular hypertension.