Background: Microvascular impairment is well documented in hypertension. In this ReSET¹ sub-study we investigated the effects of renal sympathetic denervation (RDN) on coronary flow reserve (CFR) and coronary- and forearm minimum vascular resistance (C-Rmin and F-Rmin) in patients with resistant hypertension.

Methods: A randomised, single centre, double-blind, sham-controlled clinical trial in 58 patients with resistant hypertension randomised to RDN or SHAM. Inclusion criteria: ASBP-day > 145 mmHg following stable antihypertensive treatment and 2 weeks of compliance registration. RDN was performed with the unipolar Medtronic Flex catheter (Medtronic, California, USA). CFR and C-Rmin were determined with transthoracic Doppler echocardiography and F-Rmin with venous occlusion plethysmography at baseline and six-months follow-up.

Results: Baseline mean 24-h ambulatory BP was 111±1 mmHg (RDN, n=29) and 111±2 mmHg (SHAM, n=29). Similar reductions in MAP were seen at six-months 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) (mmHg min/ml pr. 100 g LVM) and unchanged (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) (mmHg min/ml pr. 100 ml tissue) and unchanged at follow-up (0.6±0.3 vs. 0.1±0.2, P=0.17). There was a tendency toward increased baseline LVMI in the SHAM-group (121±7 (SHAM) vs. 108±3 (RDN) g/m², P=0.08), but with proportional change at follow-up (−4±7 vs. 3±5, P=0.38).

Conclusion: RDN had no significant effect on CFR, C-Rmin and F-Rmin. Thus, data does not support microvascular improvement following RDN in resistant hypertension.