Serial changes in vessel walls of renal arteries after catheter-based renal artery denervation: insights from volumetric computed tomography analysis.

Aim: Radiofrequency ablation of peri-arterial renal autonomic nerves has been studied as a potential therapeutic option for resistant hypertension. While recent clinical trials have reported its efficacy, there is paucity of data addressing the effects of the procedure on renal arteries, such as changes in vessel and lumen areas. Herein, the effect of atheroma burden on renal arteries after renal denervation was assessed using computed tomography (CT) imaging.

Materials and methods: Serial renal artery CT imaging was conducted in 38 patients from the EnligHTN™ I study, a prospective, multicenter study evaluating the efficacy of the EnligHTN multi-electrode radiofrequency ablation catheter in resistant hypertensive subjects. Cross-sectional images of renal arteries at 1 mm intervals were acquired using commercially available software (3mensio Structural Heart version 5.1). Vessel and lumen areas were manually traced in each image. Vessel wall volume (VWV) and percent vessel wall volume (P-VWV) were calculated. The measurements within the ablation (first 30 mm segments) and the non-ablation (subsequent 30 mm segment after the first bifurcation of renal arteries) zones were compared.

Results: On serial evaluation, greater increase in P-VWV and VWV was observed in the ablation zone (change in P-VWV, 6.7%±5.1% vs 3.6%±2.8%, P =0.001; change in VWV, 106.3±87.4 vs 23.0±18.2 mm3 , P =0.001). Receiver-operating characteristic analysis demonstrated baseline P-VWV in the ablation zone >37.1% as an optimal cutoff value to predict its substantial progression after the procedure (area under the curve=0.88, sensitivity 89.8%, specificity 79.1%).

Conclusion: Change in vessel wall was greater within the segments receiving renal artery denervation. Baseline VWV predicted its substantial increase after the procedure. These observations suggest that atheroma burden within the renal arteries is a potential contributing factor to vascular changes after renal sympathetic denervation.