A Novel Experimental Animal Model of Arterial Stenosis Based on Endovascular Radiofrequency Energy Application

Endoportal Radiofrequency Ablation and Stent Placement in Patients with Portal Vein Tumor Thrombosis from Hepatocellular Carcinoma: A Study on Feasibility and Safety

Background: Hepatocellular carcinoma (HCC) is the most common type of liver cancer, with 10-40% of cases involving portal vein tumor thrombosis (PVTT), leading to poor outcomes and a short survival. The effectiveness of PVTT treatment in patients with HCC is still controversial. Methods: This prospective dual-center study cohort comprised 60 patients with HCC and PVTT who underwent PVR-EPRFA-ST using a novel intravascular radiofrequency system followed by vascular stent placement across the PVTT stenosed segment under fluoroscopy guidance. Results: PVR-EPRFA-ST was technically and clinically successful in 54/60 (90%) and 37/54 (68.5%) patients, respectively. The mean tumor size, PVTT length, post-ablation luminal diameter, and median duration of the recanalized PV patency were 8.6 ± 3.4 cm, 4.1 ± 2.1 cm, 10.3 ± 1.8 mm, and 13.4 months. Higher technical and clinical success rates were associated with a longer survival (177 ± 17.3 days, HR: 0.3, 95%CI 0.12-0.71, p = 0.04; and 233 ± 18.3 days, HR: 0.14, 0.07-0.27, p < 0.001). A shorter survival was associated with Child-Pugh C (HR: 2.7, p = 0.04), multiple tumors (HR: 1.81, p = 0.03), and PVTT length (HR: 1.16, p = 0.04). Conclusions: PVR-EPRFA-ST was feasible and effective for the treatment of selected patients with PVTT, especially in patients with Child-Pugh A/B, single tumors, or a shorter PVTT length.

A novel technique of pulmonary artery banding by means of radiofrequency ablation: An experimental study in rabbits

Background

The aim of this study was to evaluate the efficacy and feasibility of a novel method of narrowing pulmonary arteries with catheter angiography using radiofrequency energy in rabbits.

Methods

A total of nine New Zealand white rabbits weighing 3.0 to 4.2 kg each were utilized in this experimental study. After the location of pulmonary artery was confirmed by echocardiography and angiography, radiofrequency energy was applied by starting with 5 W energy for the first time and increasing by 5 W, if there was no rupture to a maximum of 20 W. Multiple applications of radiofrequency energy with different durations were performed at different levels of the pulmonary artery. Eight weeks later, surviving rabbits were sacrificed. The pulmonary arteries were removed for histological investigation.

Results

Five rabbits remained alive after the experiment. There was a significant correlation between radiofrequency power and the degree of vessel thickness change in the pulmonary artery. The endothelial integrity of the tunica intima was impaired in all groups and the diameter of vessel was thickened by an average of 3.5 times.

Conclusion

The narrowing of the pulmonary artery using radiofrequency energy was successfully performed in a small sample size of experimental animals in this study.

Percutaneous Endovascular Radiofrequency Ablation for Malignant Portal Obstruction: An Initial Clinical Experience

PURPOSE

The Habib™ VesOpen Catheter is a new endovascular radiofrequency ablation (RFA) device used to treat malignant portal obstruction. The purpose of this study was to evaluate the clinical feasibility and safety of RFA with this device.

METHODS

We collected the clinical records and follow-up data of patients with malignant portal obstruction treated with percutaneous endovascular portal RFA using the Habib™ VesOpen Catheter. Procedure-related complications, improvement of symptoms, portal patency, survival, and postoperative biochemical tests were investigated.

RESULTS

The 31 patients enrolled in the study underwent 41 successful endovascular portal RFA procedures. Patients were divided into a portal-stenting (PS) group (n = 13), which underwent subsequent portal stenting with self-expandable metallic stents, and a non-stenting (NS) group (n = 18), which did not undergo stenting. No procedure-related abdominal hemorrhage or portal rupture occurred. Postablation complications included abdominal pain (n = 26), fever (n = 13), and pleural effusion (n = 15). Improvements in clinical manifestations were observed in 27 of the 31 patients. Of the 17 patients experiencing portal restenosis, 10 underwent successful repeat RFA. The rate of successful repeat RFA was significantly higher in the NS group than in the PS group. Median portal patency was shorter in the PS group than in the NS group. No mortality occurred during the 4 weeks after percutaneous endovascular portal RFA.

CONCLUSIONS

Percutaneous endovascular portal RFA is a feasible and safe therapeutic option for malignant portal obstruction. Prospective investigations should be performed to evaluate clinical efficacy, in particular, the need to evaluate the necessity for subsequent portal stenting.

Method for percutaneously introducing, and removing, anatomical stenosis of predetermined severity in vivo: the "stenotic stent"

Current in vivo models of arterial lesions often lead to unpredictable results in terms of lesion anatomy and hemodynamical significance. This study aimed to evaluate the impact of coronary stenosis using a novel in vivo adjustable stenosis model capable of mimicking advanced human coronary lesions. We developed a series of balloon expandable covered coronary stents with a central restriction, mimicking different intermediate to severe stenosis, and implanted them percutaneously in coronary arteries of eight healthy hybrid Landrace pigs. Optical coherence tomography (OCT) pullbacks and fractional flow reserve (FFR) were acquired along the artery after implantation of the stenotic stents for precise evaluation of anatomy and functional impact. Diameter and area stenosis after deployment of the stenosis implant were, on average, respectively, 54.1 ± 5.9 and 78.4 ± 5.8 % and average FFR value was 0.83 (SD 0.13). There was a low correlation between FFR and MLA evaluated by OCT (r = 0.02, p = 0.94), improved with percentage area stenosis (r = -0.55, p = 0.12), or OCT volumetric evaluation of the stenosis taking into account not only the MLA but also the length of the lesion (r = -0.78, p = 0.01). This study presents a method and proof of concept for percutaneously introducing, and removing, anatomical stenosis of predetermined severity in vivo. Such in vivo model may be used to create and evaluate the impact of focal stenoses on physiological parameters such as FFR.

The immunologic injury composite with balloon injury leads to dyslipidemia: a robust rabbit model of human atherosclerosis and vulnerable plaque

Atherosclerosis is a condition in which a lipid deposition, thrombus formation, immune cell infiltration, and a chronic inflammatory response, but its systemic study has been hampered by the lack of suitable animal models, especially in herbalism fields. We have tried to perform a perfect animal model that completely replicates the stages of human atherosclerosis. This is the first combined study about the immunologic injury and balloon injury based on the cholesterol diet. In this study, we developed a modified protocol of the white rabbit model that could represent a novel approach to studying human atherosclerosis and vulnerable plaque.