Alcohol-mediated perivascular renal sympathetic denervation for resistant hypertension (IPG801)

Hypertension is a major risk factor for cardiovascular and chronic kidney diseases. Hypertension can be primary or secondary. Primary hypertension does not have a single known cause, but secondary hypertension develops because of an underlying medical condition. Hypertension is traditionally considered resistant if it is not controlled after treatment with 3 or more antihypertensive medicines from different classes.

NICE's guideline on hypertension in adults describes diagnosing and managing hypertension, including resistant hypertension. Current treatments for hypertension include lifestyle modifications and antihypertensive medicines. Blood pressure and treatment are regularly monitored and treatment is adjusted as needed. For resistant hypertension, treatment options include additional medicines and device-based antihypertensive therapies (such as radiofrequency or ultrasound renal denervation, and carotid baroreceptor stimulation).

Before the procedure, renal artery imaging is done to evaluate renal arterial anatomy.

The procedure is usually done under local anaesthesia, with sedation and anticoagulation. A catheter is introduced through the femoral artery and advanced into each renal artery under fluoroscopic guidance. The catheter has 3 guide tubes, each containing a microneedle. Once the catheter is positioned within the target site, the 3 tubes are simultaneously deployed against the intimal surface of the renal artery. The 3 microneedles are advanced through the renal artery wall into the adventitia and surrounding perivascular space. Microdoses of neurolytic agent (medical grade dehydrated alcohol) are then infused slowly into the perivascular space from the distal to proximal end of each renal artery. This ablates the renal nerves leading to the kidney, with the aim of disrupting neurogenic reflexes involved in blood pressure control.

After the catheter is withdrawn, renal artery imaging can be done to identify any adverse vascular events related to the device or the procedure.

NICE did a rapid review of the published literature on the efficacy and safety of this procedure. This comprised a comprehensive literature search and detailed review of the evidence from 5 sources, which was discussed by the committee. The evidence included 2 randomised controlled trials and 3 single-arm studies. It is presented in the summary of key evidence section in the interventional procedures overview. Other relevant literature is in the appendix of the overview.

The professional experts and the committee considered the key efficacy outcomes to be: reduction in blood pressure, reduction in use of antihypertensive medicines, reduction in end-organ damage and improvement in quality of life.

The professional experts and the committee considered the key safety outcomes to be: pain, bleeding and damage to renal arteries or other structures.

Patient commentary was sought but none was received.

There is a placebo effect on blood pressure reduction in the evidence, and the committee was informed that such an effect is common in hypertension trials.

The evidence includes diverse groups and there may be subgroups who would benefit from the procedure.

This is an invasive procedure. Although the evidence does not show major safety concerns, this is based on evidence from limited patient numbers and needs confirming over a longer term. So, more evidence is needed on safety.

This procedure is a single intervention and not intended to be repeated.

Technology has evolved over time and renal accessory arteries can be reached using a smaller catheter to achieve a more compete denervation.