Endoscopic ultrasound-guided vascular interventions: An expanding paradigm

Endoscopic ultrasound(EUS)has expanded its arena from a mere diagnostic modality to an essential therapeutic tool in managing gastrointestinal(GI)diseases.The proximity of the GI tract to the vascular structures in the mediastinum and the abdomen has facilitated the growth of EUS in the field of vascular interventions.EUS provides important clinical and anatomical information related to the vessels'size,appearance and location.Its excellent spatial resolution,use of colour doppler with or without contrast enhancement and ability to provide images“real-time”helps in precision while intervening vascular structures.Additionally,structures such as venous collaterals or varices can be dealt with optimally using EUS.EUS-guided vascular therapy with coil and glue combination has revolutionized the management of portal hypertension.It also helps to avoid radiation exposure in addition to being minimally invasive.These advantages have led EUS to become an upcoming modality to complement traditional interventional radiology in the field of vascular interventions.EUS-guided portal vein(PV)access and therapy is a new kid on the block.EUS-guided portal pressure gradient measurement,injecting chemotherapy in PV and intrahepatic portosystemic shunt has expanded the horizons of endo-hepatology.Lastly,EUS has also forayed into cardiac interventions allowing pericardial fluid aspiration and tumour biopsy with experimental data on access to valvular apparatus.Herein,we provide a comprehensive review of the expanding paradigm of EUS-guided vascular interventions in GI bleeding,portal vein access and its related therapeutic interventions,cardiac access,and therapy.A synopsis of all the technical details involving each procedure and the available data has been tabulated,and the future trends in this area have been highlighted.

Endoscopic ultrasound-guided vascular interventions: Current insights and emerging techniques

Endoscopic ultrasound(EUS)is one of the significant breakthroughs in the field of advanced endoscopy.In the last two decades,EUS has evolved from a diagnostic tool to a real-time therapeutic modality.The luminal gastrointestinal(GI)tract provides a unique opportunity to access multiple vascular structures,especially in the mediastinum and abdomen,thus permitting a variety of EUS-guided vascular interventions.The addition of the doppler and contrast-enhanced capability to EUS has further helped provide real-time visualization of blood flow in vessels through the GI tract.EUS-guided vascular interventions rely on standard endoscopic accessories and interventional tools such as fine-needle aspiration needles and fine-needle biopsy.EUS allows the visualization of various structures in real-time by differentiating tissue densities and vascularity,thus,avoiding radiation exposure.EUS-guided techniques also allow real-time microscopic examination after target biopsy.Furthermore,many necessary interventions can be done during the same procedure after diagnosis.This article provides an overview of EUS-guided vascular interventions such as variceal,non-variceal bleeding interventions,EUSguided portal vein(PV)access with the formation of an intrahepatic portosystemic shunt,and techniques related to diagnosis of GI malignancies.Furthermore,we discuss current insights and future outlook of therapeutic modalities like PV embolization,PV sampling,angiography,drug administration,and portal pressure measurement.

Robust and Real-Time Guidewire Simulation Based on Kirchhoff Elastic Rod for Vascular Intervention Training

Virtual reality(VR) based vascular intervention training is a fascinating innovation, which helps trainees develop skills in safety remote from patients. The vascular intervention training involves the use of flexible tipped guidewires to advance diagnostic or therapeutic catheters into a patient's vascular anatomy. In this paper, a real-time physically-based modeling approach is proposed to simulate complicated behaviors of guidewires and catheters based on Kirchhoff elastic rod. The slender body of guidewire and catheter is simulated using more efficient special case of naturally straight, isotropic Kirchhoff rods, and the short flexible tip composed of straight or angled design is modeled using more complex generalized Kirchhoff rods. We derive the equations of motion for guidewire and catheter with continuous elastic energy, and then they were discretized using a linear implicit scheme that guarantees stability and robustness. In addition, we apply a fast-projection method to enforce the inextensibility of guidewire and catheter, while an adaptive sampling algorithm is implemented to improve the simulation efficiency without reducing accuracy. Experimental results reveal that our guidewire simulation method is both robust and efficient in a real-time performance.

Comparison of radiation doses between hepatic artery infusion chemotherapy and transarterial chemoembolization for liver cancer

Objective:To analyze the radiation dose received by patients during hepatic artery infusion chemotherapy(HAIC)and transarterial chemoembolization(TACE)procedures and the related influencing factors.Methods:Data of 162 cases in the HAIC group and 230 cases in the TACE group were collected.The included covariates were Age(<45/45-59/≥60 years),BMI levels(underweight/normal weight/obesity),focus Dye of tumor(present/absent),lesion size(<5 cm/≥5 cm),superselection(present/absent),hepatic vascular variation(present/absent).The endpoints were postoperative dose-area product(DAP),exposure time and Air kerma(AK).Results:Of all included patients,the HAIC group patients were younger than those in the TACE group(P=0.028).The proportion of patients with large lesions in the HAIC group was higher than the TACE group(45.7%vs.33.9%,P=0.019).The proportion of patients who had superselection was lower in the HAIC group as compared to the TACE group(61.7%vs.82.2%,P<0.001).Generally,the HAIC group has lower DAP,exposure time and AK by 36.3%(P<0.001),38.2%(P<0.001),and 41.3%(P<0.001)than the TACE group,respectively.Linear regression analysis showed the procedure method(HAIC/TACE,P<0.001),type of DSA machine(Pheno/FD20,P<0.001),BMI levels(P<0.001),age(P=0.021),lesion size(<5 cm/≥5 cm,P=0.031)significantly correlated with low DAP.In the HAIC group,the type of DSA machine and BMI correlated with the radiation dose,while in the TACE group,the type of DSA machine,BMI,and lesion size correlated with the radiation dose.Conclusion:Compared with TACE,HAIC enables doctors and patients to receive lower radiation doses.Obese patients in both HAIC and TACE groups increase the radiation exposure in interventional doctors and patients,but large lesions only affect the radiation dose in the TACE procedure.

Peripheral vascular bifurcation： features and techniques

The systemic nature of vascular atherosclerosis involves all vascular territories.. As interventional cardiologists, we are familiar with coronary artery bifurcation treatment. In other parts of the human body, the vascular tree develops similar bifurcation in the carotid, renal, aortoiliac and tibio-peroneal segments. Even with some differences depending on specific vascular wall composition, the atherosclerotic process affects all such bifurcations in a similar way.