Reversible renin mediated massive proteinuria successfully treated by nephrectomy

Renal artery stenosis presenting with nephrotic-range proteinuria: a case report

Renal artery stenosis (RAS) is commonly presented with hypertension and chronic kidney disease. We report a rare case of RAS occurring in a 78-year-old man who presented with nephrotic-range proteinuria. Renal biopsy on the left side was performed, and results showed mesangiopathic glomerulonephritis, which was not compatible with the cause of nephrotic-range proteinuria. Proteinuria was decreased by angiotensin receptor blocker, but azotemia was aggravated. Therefore, angiotensin receptor blocker was discontinued inevitably and thorough evaluation for the possibility of RAS was performed. Computed tomography angiography revealed significant RAS on the left side and a renal artery stent was inserted. After stenting, aortic dissection developed and progressed despite tight control of blood pressure. After inserting another stent graft through the true lumen of the left renal artery, the patient's renal function and proteinuria improved markedly.

Adipose tissue-derived mesenchymal stem cells improve revascularization outcomes to restore renal function in swine atherosclerotic renal artery stenosis

Reno-protective strategies are needed to improve renal outcomes in patients with atherosclerotic renal artery stenosis (ARAS). Adipose tissue-derived mesenchymal stem cells (MSCs) can promote renal regeneration, but their potential for attenuating cellular injury and restoring kidney repair in ARAS has not been explored. We hypothesized that replenishment of MSC as an adjunct to percutaneous transluminal renal angioplasty (PTRA) would restore renal cellular integrity and improve renal function in ARAS pigs. Four groups of pigs (n = 7 each) were studied after 16 weeks of ARAS, ARAS 4 weeks after PTRA and stenting with or without adjunct intrarenal delivery of MSC (10 × 10(6) cells), and controls. Stenotic kidney blood flow (renal blood flow [RBF]) and glomerular filtration rate (GFR) were measured using multidetector computer tomography (CT). Renal microvascular architecture (micro-CT), fibrosis, inflammation, and oxidative stress were evaluated ex vivo. Four weeks after successful PTRA, mean arterial pressure fell to a similar level in all revascularized groups. Stenotic kidney GFR and RBF remained decreased in ARAS (p = .01 and p = .02) and ARAS + PTRA (p = .02 and p = .03) compared with normal but rose to normal levels in ARAS + PTRA + MSC (p = .34 and p = .46 vs. normal). Interstitial fibrosis, inflammation, microvascular rarefaction, and oxidative stress were attenuated only in PTRA + MSC-treated pigs. A single intrarenal delivery of MSC in conjunction with renal revascularization restored renal hemodynamics and function and decreased inflammation, apoptosis, oxidative stress, microvascular loss, and fibrosis. This study suggests a unique and novel therapeutic potential for MSC in restoring renal function when combined with PTRA in chronic experimental renovascular disease.

Ischemic nephropathy: proteinuria and renal resistance index could suggest if revascularization is recommended

BACKGROUND

The aim of endovascular therapy in renal artery stenosis (RAS) is to preserve renal function and have a better hypertension control. The purpose of our study was to determine which biochemical and instrumental parameters could predict a better renal outcome in patients with RAS treated with percutaneous transluminal angioplasty and stenting (RPTAS).

METHODS

We performed an observational study based on 40 patients with RAS who met the following criteria before revascularization: urinary protein excretion of over 250 mg/24 h, normal renal function, and/or mild-moderate renal insufficiency (I, II, and III levels of classification of chronic kidney disease, K-DOQI).

RESULTS

Assessment at 12 months after RPTAS showed in 20 patients (Group A) that proteinuria serum creatinine (Scr) and creatinine clearance (CrCl) significantly worsened from the baseline; whereas in 20 patients (Group B) proteinuria remained unchanged and the renal function improved after the procedure.

CONCLUSIONS

In our study, the decline of renal function after RPTAS is associated with an elevated renal resistance index (RI) in both kidneys (0.83 ± 0.2) and preexisting proteinuria.

Survival and quality of life after renal angioplasty: a five-year follow-up study

OBJECTIVE

Renal percutaneous transluminal angioplasty (PTA) treatment of renal artery stenosis has been performed worldwide since 1978, but it is still a matter of debate as to what extent the patients benefit from the procedure in terms of quality of life and long-term survival.

MATERIAL AND METHODS

Of 139 patients referred for renal angioplasty owing to hypertension or pending uraemia, 105 were subsequently treated with PTA. Eighty-eight patients survived for 5 years. Fifty-nine patients were re-examined according to a protocol including physical examination, blood pressure, drug therapy, glomerular filtration rate and quality of life assessment, and an additional 29 patients were interviewed by telephone regarding quality of life. PTA was not conducted in 34 patients owing to high risks as decided at joint radiology-nephrology conferences.

RESULTS

The 5-year survival was 83% for PTA-treated patients with arteriosclerotic renovascular disease, 100% for patients with fibromuscular vascular disease and 47% for the non-PTA-treated patients. The main causes of death were cardiovascular and cerebrovascular events in both groups. Reduced blood pressure and reduced need for antihypertensive drug treatment were observed in the PTA-treated patients. The renal function was stable. A majority of the PTA-treated patients stated that they had "unrestricted" physical activity, and the physical, mental and social well-being was self-rated as level 4-5 (mostly good and very good) on a five-grade scale by 53%, 67% and 75% of the patients, respectively, at the follow-up investigation. The untreated patients were not interviewed.

CONCLUSION

The study showed a high survival rate, improved blood pressure control and stable renal function 5 years after renal PTA, and a vast majority of the patients rated their physical, mental and social well-being favourably.

Renal artery stenosis: a common, treatable cause of renal failure?

Chronic azotemic renovascular disease is common in patients with atherosclerosis. Its prevalence appears to be increasing in the aging population. How often it is the primary cause of end-stage renal disease (ESRD) is not yet certain. Some studies suggest that 10%-40% of elderly hypertensive patients with newly documented ESRD and no demonstrable primary renal disease have significant renal artery stenosis (RAS). Atherosclerotic vascular occlusive disease of the renal arteries does progress, but current rates of progression and occlusion are lower than those reported a decade ago. Methods of identifying patients whose renal function is at true risk from vascular occlusive disease and determining who will benefit from intervention remain elusive. The presence of RAS in an azotemic patient can be assessed with noninvasive and risk-free radiologic techniques, including Duplex doppler velicometry and magnetic resonance angiography. Functional tests that predict the change in renal function after revascularization are not yet available. However, a renal length of greater than 7.5 cm in the absence of renal cysts and a short history of renal functional deterioration indicate a good prognosis. Patients with recent deterioration in renal function, those with bilateral renal artery stenosis or stenosis to a single functioning kidney, those with flash pulmonary edema, advanced chronic renal failure, or ESRD (who have much to gain), those with reversible azotemia during angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor antagonist (ARB) therapy, and those whose conditions cannot be managed medically should be considered for revascularization. Results from recent controlled clinical trials of the response to percutaneous transluminal renal artery angioplasty (PTRA) and stenting indicate that improvement in blood pressure control or renal function is not a predictable outcome of renal revascularization. In azotemic groups, 25%-30% of patients achieve important recovery of renal function. Thus, significant progress has been made recently in determining whether RAS is a frequent, treatable cause of renal failure. The decision to recommend revascularization remains a difficult balance between the risks and expense of the procedure and the undoubted benefits that accrue if renal function is successfully stabilized.

Importance of blood pressure reduction for prevention of progression of renal disease

Despite reduction of stroke and coronary mortality rates, progression of renal disease to end stage continues to occur with increasing frequency. Recent studies emphasize common pathways of elevated arterial pressures that produce increased glomerular capillary pressures and increase filtered proteins in the urinary space. Such proteinuria, along with activation of the intrarenal renin-angiotensin system, endothelin, and inflammatory cytokines, magnifies progressive renal injury and fibrosis. Malignant forms of hypertension with severe arteriolar injury and proteinuria can be treated effectively with current antihypertensive regimens with improved patient survival. Several recent studies indicate improved renal outcomes in proteinuric diseases, generally regardless of the specific antihypertensive agent. Recent trials of hypertensive subjects with minimal proteinuria demonstrate slower rates of disease progression than that seen in subjects with proteinuria above 1 gram per day. Reduction of arterial pressures, particularly when it leads to reduced proteinuria, can slow the progression of many renal diseases.

Proteinuria in atherosclerotic renovascular disease

Proteinuria is well described in atherosclerotic renovascular disease (ARVD), but the prevalence is unknown, and the pathogenesis may vary between patients. Substantial proteinuria (> 2 g/day) however, would be regarded by many as atypical of ARVD. We studied 94 patients (52 male) with ARVD, median age 67 years (range 49-87). Digital subtraction angiography was performed on all patients. Protein was assayed in 24-h urine samples and GFR derived using the Cockroft-Gault formula. Forty-nine patients (52%) had proteinuria < 0.5 g/24 h. Proteinuria increased with worsening renal function. Biopsies from seven non-diabetic patients with substantial proteinuria showed: minimal changes (1); glomerular sclerosis with marked ischaemic changes (3); focal glomerulosclerosis (2); and athero-emboli (1). Proteinuria, rather than being indicative of other pathology, is often a marker of severity of parenchymal disorder in atherosclerotic nephropathy, which itself is the major determinant of renal dysfunction in patients with ARVD.

Is renal revascularization in diabetic patients worthwhile?

PURPOSE

This retrospective review describes surgical management of atherosclerotic renovascular disease (RVD) in hypertensive adults with diabetes mellitus.

METHODS

From July 1987 through July 1995, 54 consecutive hypertensive diabetics (mean 213/103 mm Hg; mean medications three drugs) requiring either insulin (16 patients) or oral hypoglycemic therapy (38 patients) had operative repair of atherosclerotic RVD. Renal dysfunction (serum creatinine [SCr] > or = 1.3 mg/dl) was present in 82% of patients (mean SCr 2.4 mg/dl). Associations between blood pressure and renal function response to operation and preoperative parameters were examined. Clinical characteristics, response to operation, and dialysis-free survival were compared with those of 291 nondiabetic patients.

RESULTS

Four (7.4%) operative deaths occurred. Among 50 survivors blood pressure response was considered cured or improved in 72% and unchanged in 28%. Of 42 patients with renal dysfunction 40% had improved function including three patients removed from dialysis. No preoperative parameter examined demonstrated a significant association with blood pressure or renal function response. During follow-up 10 additional patient deaths occurred, and eight patients progressed to dialysis dependence. Time to death or dialysis was associated with preoperative estimates of glomerular filtration (p = 0.03) and the change in estimates of glomerular filtration after operation (p = 0.01). Compared with 291 nondiabetics, the diabetic group had no statistical difference in improved function response (40% vs 51%, p = 0.21); however, diabetics had a significantly lower rate of beneficial blood pressure response (72% vs 89%, p = 0.01) and an increased risk of dialysis or death during follow-up (p = 0.02). By multivariate analysis independent predictors of time to death or dialysis included the presence of diabetes mellitus, patient age, history of congestive heart failure, and increased serum creatinine.

CONCLUSIONS

Most of the selected diabetic patients had a beneficial blood pressure response after undergoing operative repair of atherosclerotic RVD, albeit at a lower rate compared with nondiabetics. In diabetics poor renal function before and after operation was associated with progression to dialysis and death. Improved renal function after operation was associated with improved survival; however, function response to renal revascularization was difficult to predict.