23 Oct 2024
Case report: Renal denervation using ultrasound energy (uRDN)
In this case report, we examine an advanced technique for renal denervation (RDN)—ultrasound energy—employed to manage severe hypertension in patients with complex medical histories.
Case Report : Renal Denervation Using Ultrasound Energy (uRDN)
Patient Profile
A 74-year-old female with a 9-year history of hypertension and moderate renal dysfunction (GFR 48 ml/min/m²) presented with refractory hypertension. Despite being on five antihypertensive medications, her office blood pressure remained at 190/115 mmHg, with 24-hour ABPM showing 165/83 mmHg. Due to resistant hypertension, she was referred for renal denervation using ultrasound energy.
Procedure Overview
The procedure was performed using the Paradise™ ultrasound catheter. The patient received light sedation and local anesthesia at the right groin puncture site.
Ultrasound RDN of left renal artery
Steps and Tips
- Arterial access:
The right common femoral artery was accessed using the Seldinger technique, and a 7F sheath was introduced. The pigtail catheter tip should be placed just above the origin of the renal arteries, usually at the level of the superior margin of the L2 vertebral body. This allows for optimal contrast injection to visualize both renal arteries. - Positioning and imaging:
The IMA guiding catheter (55 cm) was advanced into the renal artery under fluoroscopy. Initial imaging assessed the renal arteries to ensure no significant stenosis, accessory renal arteries, or anatomical variations were present. Heparin (80-100 IU/ kg) was given to achieve an activated clotting time (ACT) of at least 250 seconds. - Balloon catheter preparation:
The Paradise™ catheter, which includes an inflatable balloon and ultrasound transducers, was advanced to the main renal artery. Once in position, automatic low-pressure inflation was initiated. Contrast injection confirmed complete renal artery occlusion and balloon apposition, ensuring uniform energy delivery to the vessel wall. - Ultrasound ablation:
Ultrasound energy was delivered for 7 seconds per ablation point, with continuous monitoring of the cooling system to prevent overheating. The cooling system circulates sterile water through the inflated balloon to protect the arterial wall from excessive heat. - Sequential ablations:
The catheter was repositioned along the renal artery to perform three ablations, targeting different segments for comprehensive denervation. Gentle catheter movement and full balloon deflation before repositioning were required to minimize the risk of vascular injury. Both renal arteries were treated in a similar manner. - Post-procedure and follow-up:
After the procedure, the catheter and sheath were removed, and the femoral artery was closed with a closure device (AngioSeal™). The patient was observed for several hours and discharged the following day with follow-up instructions. At six months, her office blood pressure had significantly decreased to 120/70 mmHg, with 24-hour ABPM showing 128/65 mmHg, reduced antihypertensive medication dosage, and fewer side effects.
Key Tips and Tricks:
- Ensure precise balloon inflation for uniform arterial wall contact, avoiding under- or over-inflation.
- Continuous monitoring of the cooling system by the generator is vital to prevent overheating and protect the arterial wall.
- Reposition the catheter carefully between ablations to cover 1-3 renal artery segments for comprehensive denervation without overlapping areas of energy delivery.
- Different or multiple balloon sizes may be needed depending on arterial anatomy variations.
