Objective To explore relationship between sympathetic activity and mechanism of hypertension, observe the treatment of renal artery denervation for hypertension, to assess the validity and safety of the treatment.
Methods 18 mongrel dogs were divided into two groups, 10 dogs were made to neurogenic hypertension model through the compression of the demyelinated vagus nerve by carotid sheath vessels pulse, another eight as the control group, two groups were operated by renal arterial radiofrequency ablation with 10 w power, no more than 60°C, at least 2 min. Blood pressure and other parameters were monitored at preoperative and 1 week, 2 weeks, 4 weeks, 10 weeks post operation. Renin activity, angiotensin II, aldosterone, and creatinine were measured at the same time.
Results we succeed in establishing the canine neurogenic hypertension model and the blood pressure were substantially reduced after sympathetic denervation. After modelling, the systolic pressure increased from 155.7±21 mm Hg to 179.5±23 mm Hg, and the diastolic pressure increased from 117.4±18.9 mm Hg to 138.2±13.4 mm Hg, there was a significant difference (p<0.01). Blood pressure decreased significantly in both the control group and blank group after renal denervation at 2 weeks, 4 weeks, 10 weeks, especially after ablation 10 weeks the blood pressure decreased more obviously (systolic blood pressure 179.5±23 mm Hg vs 143.9±11.7 mm Hg, diastolic blood pressure 138.2±13.4 mm Hg vs 114.9±15.5 mm Hg, p<0.001). Renin activity (PRA), Angiotensin II (Ang II) and aldosterone (Ald) levels were decreased after ablation, the levels of PRA detected preoperative, 1 week, 2 weeks, 4 weeks and 10 weeks after ablation were 0.26±0.09 ng/ml/h, 2.2±1.44 ng/ml/h, 0.71±0.57 ng/ml/h, 0.49±0.35 ng/ml/h, 0.24±0.12 ng/ml/h, the levels of Ang II were 76.9±14.3 pg/ml, 120±25.2 pg/ml, 97.1±21.9 pg/ml, 76.5±13.7 pg/ml, 64.4±11.1 pg/ml, the levels of Ald were 1.8±1.27 ng/dl, 7.5±1.73 ng/dl, 6.6±3.34 ng/dl, 4.6±2.59 ng/dl, 3.3±1.61 ng/dl. But the levels of Cr were not changed too much, it shows no great difference (57±12.7 umol/l, 45±7.4 umol/l, 36±19.2 umol/l, 43±8.6 umol/l, 41±21.8 umol/l p>0.05).
Conclusion Sympathetic nerves accelerate the development and progression of hypertension, catheter-based renal denervation causes substantial and sustained blood pressure reduction, and it cause no injury on renal, If in the future it can be widely applied in the treatment of hypertension, it will have broad application prospects and huge social benefits.