A new treatment with percutaneous denervation of the renal sympathetic nerve

In recent years, the incidence of hypertension in China has been increasing year by year, and it is now estimated that the number of people suffering from hypertension has exceeded 200 million. Hypertension is an important risk factor for cardiovascular diseases, a serious threat to human health, and one of the most significant disease burdens in China. Despite the impressive achievements of pharmacological treatment of hypertension in recent years, it has played an important role in reducing blood pressure as well as cardiovascular events. However, there are still many patients with refractory hypertension whose blood pressure is not effectively controlled even after the use of various antihypertensive drugs. The occurrence of cardiovascular events in these patients is significantly increased, resulting in a huge family and social economic burden. After applying the best and tolerable doses of three or more antihypertensive drugs (including diuretics) in reasonable combination based on lifestyle improvement, blood pressure remains above the target level on a medication-adjusted basis for a certain period of time (at least >1 month), or blood pressure can be effectively controlled only after taking four or more antihypertensive drugs, which is called refractory hypertension. There are many clinical factors affecting refractory hypertension, including poor lifestyle improvement, poor compliance with medications, unreasonable combination of medications, combined medications affecting the efficacy of antihypertensive drugs, and the presence of secondary hypertension. These patients tend to have a combination of multiple cardiovascular risk factors such as advanced age, obesity, left ventricular hypertrophy, chronic kidney disease and diabetes mellitus. The main pathophysiological mechanisms of true refractory hypertension include physiological abnormalities in the aldosterone pathway of the renin-angiotensin-aldosterone system (RAAS), water and sodium retention, and over-activation of the sympathetic nervous system, and the enhanced and persistent sympathetic as well as RAAS activity is one of the important pathogenic mechanisms of refractory hypertension. The kidney has an important role in the pathogenesis of refractory hypertension, in which local sympathetic hyperactivation in the kidney is also an important pathophysiological mechanism of refractory hypertension. Therefore, blocking renal sympathetic nerves has the potential to be an effective approach for the treatment of refractory hypertension. The published SimplicityHTN-1 and SimplicityHTN-2 studies did demonstrate that percutaneous renal sympathetic denervation (RDN) can safely and effectively treat intractable hypertension. However, the subsequent release of the SimplicityHTN-3 study caused a waterloo battle for RDN, which did not further reduce blood pressure in patients with intractable hypertension compared to sham surgery, and called into question the therapeutic role of RDN in the field of hypertension. But the former glory of RDN aside, it is more beneficial to sink our teeth into this treatment method and study it carefully. In addition to intractable hypertension, many studies have examined the “pleiotropic” effects of RDN, such as its beneficial effects on ventricular arrhythmias, atrial fibrillation, heart failure, insulin resistance, sleep apnea, and lipids. In addition, we should perhaps think beyond the intrinsic idea of intractable hypertension and not “mythologize” the therapeutic effect of RDN as a “life-saver” when other treatments are ineffective, and study it as a treatment for hypertension. It is important to explore the value of RDN in the general hypertensive population. Therefore, a different approach is needed in the study of RDN. It is important to take an active and cautious approach to this technology and not to proceed blindly nor to hesitate. Clinical and basic research related to RDN should be actively carried out. Research on the technology itself is also needed. For example, improvement of the ablation catheter and improvement of the ablation medium (e.g., using ultrasound) can further increase the safety and effectiveness of the technique. More research is needed to clarify whether percutaneous denervation of sympathetic nerve ablation is a short-lived technique or not.