[Management of renal atrophy in hypertensive patients: experience in Lille].

Abstract

In the absence of specific treatment, patients with renal vascular disease develop renal atrophy. This population frequently has hypertension refractory to medical treatment. The patients who may respond to revascularization or at the worst to a nephrectomy must be identified to optimize their therapeutic management.
We conducted an observational retrospective study of hypertensive patients with unilateral renal atrophy (renal height < 9 cm) followed at the Lille University Hospital Center from 1998 to 2006. Hypertension, renal clearance (by scintigraphy with MAG3), and hypersecretion of renin (segmental/selective venous renin samples) were studied. We subsequently classified the patients into 3 groups. Medical treatment was optimized for all.
The mean follow-up period was 1.3+/-0.2 years. Eight patients were treated medically (group 1). Endovascular revascularization was used to treat the subjects for which atrophic kidney function accounted for more than 10% of their total renal function and with stenosis of the renal artery (>70%) (group 2, n=19). Those with a small nonfunctional kidney (<10% of total renal function) and hypersecretion of renin (ratio>1.5 in relation to the contralateral kidney) underwent a nephrectomy (group 3, n=8). The reduction in systolic blood pressure (SBP) was 27 mm Hg and diastolic blood pressure (DBP) 14 mm Hg for the overall study population (p < 0.001), without any significant aggravation of renal function. In group 1, the reduction in blood pressure was lower, with medical treatment alone; SBP fell by 13 mm Hg and DBP by 4mm Hg (p=ns) ; this group had the lowest initial blood pressure. In group 2, revascularization made it possible to improve SBP by 26 mm Hg and DBP by 14 mm Hg (p < 0.01) without significant impairment of renal function. Group 3 showed the most spectacular improvement in blood pressure, with SBP dropping by 40 mm Hg and DBP by 19 mm Hg (p=0.016). But it was also in this group that we observed an aggravation in the rate of glomerular filtration with a nonsignificant reduction of 12.8 mL/min, nonetheless superior to that expected according to the preoperative scintigraphy.
The results of this work underline the importance of multidisciplinary management of patients with small ischemic kidneys. Preselection of patients in unstable clinical situations (refractory hypertension, progressive kidney failure, flash pulmonary edema) by isotopic and endocrinal renal evaluation provides a basis for deciding on treatment. The existence of a renin ratio >1.5 can identify the patients most likely to respond to nephrectomy. The reduction of renal function following nephrectomy must be considered in the discussion about treatment. The functional threshold initially defined at 10% may be lowered to 5%, to limit this postoperative reduction.