Effect of captopril on the renal veno-arterial gradient of erythropoietin and oxygen in unilateral renal artery disease

Abstract

Jensen JD, Eiskjær H, Madsen B, Egeblad M, Nielsen CB, Pedersen EB. Effect of captopril on the renal veno-arterial gradient of erythropoietin and oxygen in unilateral renal artery disease. Scand J Clin Lab Invest 1993; 53: 859-865.

Twenty-nine patients with unilateral renal artery stenosis or occlusion were investigated. The veno-arterial gradient (VA-gradient) of erythropoietin (EPO), haemoglobin oxygen saturation and plasma renin activity (PRA) was determined separately in each kidney before and 1 h after angiotensin converting enzyme inhibition (ACE-inhibition). The VA-gradient of EPO and of hemoglobin oxygen saturation were the same in the affected and unaffected kidney during basal conditions. During ACE-inhibition the VA-gradient of EPO disappeared on the affected side but not on the unaffected side. A fall in s-EPO after ACE inhibition was demonstrated in the renal vein on the affected side (– 1.4U1⁻¹, p < 0.01), in the contralateral vein (–0.8UI⁻¹, p < 0.01) and in the aorta (-0.6UI⁻¹, p<0.01). The O₂-gradients were reduced on both sides after captopril, from 10.8-7.5% (p < 0.04) on the affected side and from 10.8-9.0% (p < 0.04) on the contralateral. It is suggested that the stimulated renin-angiotensin system may be important for EPO production in the affected kidney in unilateral renal disease.

Key Words:

• angiotensin converting enzyme inhibition
• arterial hypertension
• captopril
• erythropoietin
• oxygen saturation
• renal artery stenosis