RENAL SYMPATHETIC DENERVATION AND NEURO-HORMONAL EVALUATION BY SELECTIVE VENOUS CATHETERIZATION: THE RESIDENCY STUDY

Abstract

Objective: Renal denervation (RD) is effective in reducing blood pressure (BP) in hypertensive patients, but the pathophysiologic mechanisms underlying the variable individual response are unclear and early markers of procedural success are lacking. The aim of the study was to evaluate intra-/peri-operative effects of RD on the renin-angiotensin-aldosterone system (RAAS) either as determinants and markers of efficacy. Design and method: Patients with resistant hypertension and eGFR>45 ml/min underwent radiofrequency-RD (Medtronic Symplicity-Spyral) with simultaneous sampling of the renal veins (RV), left adrenal vein and pre-renal inferior vena cava (IVC). Samples were collected before (t0) and 15’ after RD from each sequentially-approached side. Additional peripheral blood samples collected on the morning before RD and 3h, 24h and 7 days after the procedure were tested for renin, aldosterone and cortisol. During this timeframe, antihypertensive therapy remained unchanged. Results: Ten patients were recruited (61±11yo; 30%F; BP = 149/84 ±11/12 mmHg on 4 (range 3-6) antihypertensive drugs). Peripheral renin concentration showed no significant changes during/immediately after RD and up to 7 days after, in spite of the observed BP reduction (136/78 ±17/15 mmHg; p<0.05). Similarly, RV renin was unaffected by ipsilateral RD compared to the corresponding t0 values (p = 0.899). Aldosterone and cortisol increased in the adrenal vein during RD (p<0.001), but their IVC-corrected ratio and their peripheral plasma concentrations at follow-up did not, likely reflecting a self-limiting stress reaction. Conclusions: These results do not suggest any direct blunting effect of RD on RAAS, and do not support the contention of monitoring acute RAAS changes as proxies for procedural effectiveness.