Effects of Renal Denervation on Coronary Flow Reserve and Forearm Dilation Capacity in Patients with Treatment-resistant Hypertension. A Randomized, Double-blinded, Sham-controlled Clinical Trial

Background: Microvascular impairment is well documented in hypertension. We investigated the effect of renal sympathetic denervation (RDN) on cardiac and peripheral microvasculature in patients with treatment-resistant essential hypertension (TRH).

Methods: A randomized, single centre, double-blinded, sham-controlled clinical trial. Fifty-eight patients with TRH (ambulatory systolic BP (ASBP) ≥ 145mmHg) despite stable treatment were randomized to RDN or SHAM. RDN was performed with the unipolar Medtronic Flex catheter. Coronary flow reserve (CFR) and coronary- and forearm minimum vascular resistance (C-Rmin and F-Rmin) were determined using transthoracic Doppler echocardiography and F-Rmin with venous occlusion plethysmography at baseline and at six-months follow-up.

Results: RDN was performed with 5.3±0.2 lesions in the right renal artery and 5.4±0.2 lesions in the left. Baseline ASBP was 152±2mmHg (RDN, n=29) and 154±2mmHg (SHAM, n=29). Similar reductions in MAP were seen at follow up (-3.5±2.0 vs. -3.2±1.8, P=0.92). Baseline CFR was 2.9±0.1 (RDN) and 2.4±0.1 (SHAM), with no significant change at follow-up (0.2±0.2 vs. -0.1±0.2, P=0.57). C-Rmin was 1.9±0.3 (RDN) and 2.7±0.6 (SHAM) (mmHgmin/ml pr. 100g) and did not change significantly (0.3±0.5 vs. -0.4±0.8, P=0.48). F-Rmin was 3.6±0.2 (RDN) and 3.6±0.3 (SHAM) (mmHgmin/ml pr. 100ml tissue) and unchanged at follow-up (4.2±0.4 vs. 3.8±0.2, P=0.17). Left ventricular mass index was unchanged following RDN (-4±7 (RDN) vs. 3±5 (SHAM) (g/m) P=0.38).

Conclusion: The current study does not support positive effects of RDN on microvascular impairment in TRH.