Efficacy of catheter-based ultrasound renal denervation in the treatment of hypertension

BACKGROUND Hypertension(HTN)is a prevalent chronic health condition that significantly increases the risk of cardiovascular diseases-associated mortalities.Despite the use of antihypertensive medications,numerous patients fail to achieve guidelinerecommended blood pressure(BP)targets.AIM To evaluates the efficacy of catheter-based ultrasound renal denervation(uRDN)for the treatment of HTN.METHODS Relevant studies were identified through searches in PubMed,Embase,the Cochrane Library,Web of Science,and China National Knowledge Infrastructure,with a cut-off date at April 1,2024.A random-effects model was employed in this study to mitigate potential biases.The risk of bias for included studies was assessed using the Cochrane Risk of Bias assessment tool.Statistical analyses were conducted using Review Manager version 5.3.This meta-analysis incorporated four studies encompassing a total of 627 patients.The reporting bias of this study was deemed acceptable.RESULTS Compared to the Sham group,the uRDN group demonstrated a significant reduction in daytime ambulatory systolic BP(SBP)[mean difference(MD)-3.87 mmHg,95%confidence interval(CI):-7.02 to-0.73,P=0.02],office SBP(MD-4.13 mmHg,95%CI:-7.15 to-1.12,P=0.007),and home SBP(MD-5.51 mmHg,95%CI:-8.47 to-2.55,P<0.001).However,there was no statistically significant reduction observed in either 24-hour or nighttime ambulatory SBP levels.Subgroup analysis shows that uRDN can significantly reduce the SBP in patients with non-resistant HTN(MD-6.19 mmHg,MD-6.00 mmHg,MD-7.72 mmHg,MD-5.02 mmHg,MD-3.61 mmHg).CONCLUSION The current evidence suggests that uRDN may effectively reduce home,office,and daytime SBP in patients with HTN,particularly in those with non-resistant HTN.

Effect of Aging on Hardening Behavior of 15-5 PH Stainless Steel

Microstructure transformation and aging hardening behavior of 15-5 PH stainless steel were studied by optical microscopy （OM）, X-ray diffraction （XRD） and transmission electron microscopy （TEM）. The results showed that the 15-5 PH stainless steel consists of NbC precipitates and lath matensite with a high dislocation density after solution treatment. With increasing aging temperature and aging time, the martensitic laths were resolved gradually. Meanwhile, the nanometric-sized Cu precipitates gradually coarsened and lost their coherency with＇the martensite matrix, which exhibited an elliptical shape finally. Fine Cu precipitates can lead to significant dispersion hardening effect, while the coarsened Cu precipitates have no contribution to strengthening. The reversed austenite was observed in the speci- mens aged at 550 ℃ and above; moreover, the amount of reversed austenite increased as aging temperature in- creased. The precipitation hardening behavior of 15-5 PH stainless steel may depend on the balance between the softening caused by the formation of reversed austenite and the hardening caused by the precipitation of copper.