Background:
patients with chronic renal insufficiency are an ideal group for renal denervation (RDN), because of the increase in sympathetic tone. This increase leads to sodium retention, reduction of perfusion of the kidney and to excessive activation of renin angiotensin aldosterone system. The activation of the sympathetic system significantly contributes to the progression of chronic renal insufficiency. The consequences the hyperactivity of the sympathetic system are affected by selective renal sympathectomy. RDN demonstrably reduces retention of sodium, reduces the production of renin and significantly reduces renal vascular resistance. Furthermore, RDN reduces microalbuminuria and renal podocyte damage in experimental model. RDN also improves renal function in the model of acute Glomerulonephritis. In patients with resistant hypertension and preserved renal function, it was also shown that renal denervation improves renal resistant index and significantly decreases microalbuminuria. The procedure was found to be safe in all studies with renal denervation and was not associated with deterioration of renal function. Several experimental data exist on the effectiveness of RDN in chronic renal insufficiency. In a model of acute renal failure in mouse (endotoxemia model), it was shown that RDN has protective effect on renal function. The decline in the glomerular filtration during endotoxemia was significantly lower in the group treated with RDN compared to the control group. In addition, the renal flow during acute renal failure after RDN was improved. In the model of heart failure in mice, it has been shown that RDN in combination with olmesartan reduces albuminuria and the damage of podocytes and also reduces the levels of renal norepinephrine, angiotensinogen, angiotensin II, and the level of oxidative stress.
Very few data on the effect of RDN on renal function in human were also published. Renal damage in hypertensives subject was not found after RDN with the Symplicity system more than 3 years post procedure. Mahfoud and coworkers showed that subject treated with RDN had lower blood pressure and renal resistive index and at the same time stabilize their renal function. The number of patients with microalbuminuria or macroalbuminuria decreased significantly one year after RDN.
RDN has also positive effect on albuminuria and proteinuria in patients with preserved renal function. The first studies performed in patients with chronic kidney disease (CKD stage 3-4) and resistant hypertension was done by Hering et coworkers. In this study, 15 patients with an average eGFR of 31ml/min/1, 73m2 underwent RDN. The authors were able to show that RDN effectively lowers blood pressure and was not associated further deterioration of renal function. RDN had other positive effects on hemoglobin concentration , proteinuria and on BNP levels. Moreover, the augmentation index of peripheral arteries was also improved by RDN. This work showed multiple effects of RDN beyond the reduction of blood pressure. We, therefore think that patient with chronic kidney disease are good candidates for RDN. However, the mentioned study has a relatively short term follow up (6 months to one year) and does not have a comparative arm.
Aim of study :
our proposed trial aimed to show that RDN not only contribute to improve the control of blood pressure in patients with resistant hypertension but also has protective effects on kidney function in subjects with chronic kidney disease. Our trial will have a comparative arm and will last 3 years.
Planned intervention:
The two strategies that are going to be compared are optimal medical therapy against optimal medical therapy with renal denervation.
