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Effect of enalapril in subjects with hypertension associated with moderate to severe renal dysfunction
Insights
Enalapril effectively controls blood pressure in hypertensive patients with renal dysfunction. This angiotensin-converting enzyme inhibitor reduces protein excretion and increases renal plasma flow without compromising glomerular filtration rate.
Area of Science:
- Nephrology
- Cardiovascular Medicine
- Pharmacology
Background:
- Hypertension with renal dysfunction presents complex management challenges.
- The renin-angiotensin system plays a crucial role in blood pressure regulation and renal function.
- Angiotensin-converting enzyme (ACE) inhibitors are key in managing hypertension.
Purpose of the Study:
- To evaluate the effects of enalapril maleate on blood pressure, renal function, and proteinuria.
- To assess the impact of enalapril on potassium homeostasis in patients with moderate to severe renal dysfunction.
- To investigate the renal protective potential of ACE inhibition in pre-existing renal disease.
Main Methods:
- Nine patients with hypertension and renal dysfunction (inulin clearance 9–48 mL/min/1.73 m2) received enalapril monotherapy or enalapril/furosemide combination therapy.
- Blood pressure, plasma renin activity, plasma aldosterone, and serum potassium levels were monitored.
- Renal function was assessed using inulin clearance, creatinine clearance, and para-aminohippurate clearance.
- Urinary protein excretion was measured to evaluate antiproteinuric effects.
Main Results:
- Enalapril demonstrated effective control of systolic and diastolic blood pressure.
- Significant increase in effective renal plasma flow and decrease in filtration fraction were observed.
- Urinary protein excretion was markedly reduced, indicating an antiproteinuric effect.
- While serum potassium increased, clinical hyperkalemia was not observed.
Conclusions:
- Enalapril therapy leads to efferent arteriolar dilation, preserving glomerular filtration rate.
- ACE inhibition may mitigate the effects of angiotensin II on protein passage across the glomerulus.
- Interruption of the renin-angiotensin system with enalapril may offer renal protective benefits in patients with renal disease.
Abstract:
The purpose of this study was to define the effect of the angiotensin-converting enzyme inhibitor, enalapril maleate, on blood pressure, renal function, protein excretion, and potassium homeostasis in patients with hypertension associated with moderate to severe renal dysfunction. Nine patients, having an initial inulin clearance between 9 and 48 mL/min/1.73 m2, were treated with enalapril monotherapy (n = 6) or enalapril/furosemide (n = 3) combination therapy. Systolic and diastolic blood pressures were well controlled. Supine plasma renin activity was stimulated; the supine plasma aldosterone level was suppressed, with a resultant increase in the serum potassium level. Clinical hyperkalemia was not observed. Glomerular filtration rate, assessed by inulin and creatinine clearances, was not significantly changed. Effective renal plasma flow, assessed by paraaminohippurate clearance was significantly increased, with a resultant decrease in filtration fraction. Importantly, urinary protein excretion was markedly reduced. These results suggest that enalapril therapy produces efferent arteriolar dilitation with preservation of the glomerular filtration rate. Enalapril therapy may also blunt the effects of angiotensin II on transglomerular passage of protein, as demonstrated by reduced proteinuria. These findings suggest that interruption of the renin-angiotensin system in patients with preexisting renal disease may have renal protective effects.