IMPACT OF AGGRESSIVE BLOOD PRESSURE REDUCTION ON KIDNEY FUNCTION AFTER RENAL DENERVATION

Abstract

Objective: Renal denervation (RDN) seems to be safe in patients with true resistant hypertension (RHTN). However long-term effect of significant decrease of blood pressure (BP) level on renal function is lacking. We aimed to investigate renal safety of the procedure depending on the degree of BP reduction. Design and method: A total of 22 patients (age 56,1 ± 10.2 years, 9 males) with true RHTN underwent bilateral RDN procedure (Symplicity RDN System, Medtronic, USA). Office BP, ambulatory BP monitoring, applanation tonometry with the calculation of systolic and diastolic central aortic pressure (sCAP and dCAP), urine levels of NGAL, KIM-1, L-FABP, serum levels of Cystatin C (sCys) and creatinine (sCr) were obtained at baseline, 6-month, 12-month and 24-month follow-up. Renal function was analyzed using CKD-EPI sCr (GFR_CKD-EPI_sCr) and CKD-EPI sCys (GFR_CKD-EPI_sCys) equation. Results: All patients were divided into 3 groups according BP reduction: 1 – BP increase above 0 mmHg; 2 – BP reduction from 0 to −30 mmHg; 3 - BP reduction below 31 mmHg. There were an increased urine KIM-1 level associated with decreased 24-dBP at 12-month follow-up (r = −0,962, p = 0,009). An increased sCr level was registered in a group with decreased dCAP (83,4 ± 8,24; 82,00 ± 7,95; 142,00 ± 9,37; F = 23,476; p = 0,01) and 24-hour sBP (78,3 ± 3,7; 88,2 ± 6,78; 142,00 ± 8,76; F = 61,987; p = 0,004) at 6-month follow-up, also sCr level was associated with decreased 24-hour sBP at 12-month follow-up (r = −0,437, p = 0,04). An increased sCys was registered in a group with decreased sCAP (1,39 ± 0,19; 0,88 ± 0,10; 1,01 ± 0,17; F = 6,156; p = 0,01) and an increased urine L-FABP level – in a group with decreased office dBP (3531,33 ± 1795,04; 997,51 ± 1096,83; 7351,66 ± 3296,97; F = 12,103; p = 0,002) at 6-month follow up. Increased sCys level was registered in a group with decreased 24-hour sBP (0,95 ± 0,16; 0,98 ± 0,12; 1,56 ± 0,15; F = 8,476; p = 0,02) and 24-hour dBP (0,91 ± 0,13; 1,02 ± 0,10; 1,56 ± 0,45; F = 11,121; p = 0,01), decreased GFR_CKD-EPI_sCr was associated with decreased 24-hour dBP (r = 0,691, p = 0,01) at 24-month follow up. Conclusions: Renal function worsening in long-term follow-up may be due to significant decrease of BP as a result of RDN. Therefore, we can suggest the occurrence of the J-curve phenomenon in relation to the kidneys and a further increase of cardiovascular risk.