Effect of vascular geometry on haemodynamic changes in a carotid artery bifurcation using numerical simulation.

OBJECTIVES: The geometry of carotid bifurcation is a crucial contributing factor to the localization of atherosclerotic lesions. Currently, studies on carotid bifurcation geometry are limited to the region near to bifurcation. This study aimed to determine the influence of carotid bifurcation geometry on the blood flow using numerical simulations considering magnitude of haemodynamic parameters in the extended regions of carotid artery. METHODS: In the present study, haemodynamic analysis is carried out using the non-Newtonian viscosity model for patient-specific geometries consisting of both Left and Right carotid arteries. A 3D patient-specific geometric model is generated using MIMICS, and a numerical model is created using ANSYS. RESULTS: The results obtained from patient-specific cases are compared. The influence of geometric features such as lumen diameter, bifurcation angle, and tortuosity on the haemodynamics parameters such as velocity, WSS, pressure, Oscillatory Shear Index (OSI), and Time-Averaged Wall Shear Stress (TAWSS) are compared. CONCLUSION: The results demonstrate significant changes in the flow regime due to the geometric shape of the carotid artery. It is observed that the lower value of TAWSS occurs near the bifurcation region and carotid bulb region. In addition, the higher value of the (OSI) is observed in the Internal Carotid Artery (ICA) and the tortuous carotid artery region. However, it is also observed that apart from the bifurcation angle, other factors, such as tortuosity and area ratio, play a significant role in the flow dynamics of the carotid artery.

A Cost-Effective Approach to Resistant AV Fistula Stenosis: Successful Treatment Using Coronary OPN NC® Balloon in a Low-Income Setting.

Stenosis in the anastomotic site or venous limb of an arteriovenous fistula (AVF) is the most frequent cause of AVF failure. Percutaneous angioplasty with a standard or high-pressure balloon is the first-line treatment for AVF stenosis due to its higher technical success rate (90%) and lower complication rate (4%). Almost 20% of stenosis cases are resistant or undilatable by regular-pressure balloon angioplasty due to fibrosis, leading to technical failure or restenosis. Alternative therapies, such as atherectomy devices or cutting balloons, are expensive and difficult to obtain in low-income developing countries. We successfully treated resistant AVF stenosis with a coronary OPN-NC® ultra-high-pressure balloon and produced a good angiographic result with technical success. Coronary hardware is easily available and relatively cheaper compared to dedicated peripheral balloons or devices in our country due to reuse, which can be a boon in such type of cases. According to the standard hospital protocol, Cathlab hardware was reused.

Percutaneous intervention for symptomatic central vein stenosis in patients with upper limb arteriovenous dialysis access.

Central venous stenosis is an important hindrance to long-term maintenance of arteriovenous access in the upper extremities in dialysis patients. AIM: The present study was done to determine feasibility and clinical success of endovascular approach for the treatment of symptomatic central venous stenosis associated with significant ipsilateral limb edema in dialysis patients with vascular access in the upper limb. METHODS: A database of hemodialysis patients who underwent endovascular treatment for central venous stenosis from January 2014 to January 2017 at our institute was retrospectively reviewed. Follow-up was variable. RESULTS: The study included ten patients (6 men and 4 women) with a mean age of 45.2 years, who underwent thirteen interventions during a period of 3 years. The technical success rate for endovascular treatment was 100%. One patient underwent primary PTA (percutaneous transluminal angioplasty). Seven patients underwent primary PTA and stenting. Three patients underwent secondary PTA. One among these patients underwent secondary PTA twice along with fistuloplasty. One patient underwent secondary PTA with stenting. No immediate complications were encountered during the procedure. Our study shows a primary patency rate of 67% and 33% at 6 months and 12 months for PTA with stenting. Our study also shows secondary or assisted primary patency of 75% at 6 months of follow-up. CONCLUSIONS: Endovascular therapy (PTA) with or without stenting for central venous stenosis is safe, with low rates of technical failure. Multiple additional interventions are the rule and long-term patency rate is not very good.

A rare coronary artery anomaly: duplication of right coronary artery with separate ostium on 64-row multidetector computed tomography

Coronary artery anomalies are rare, and their incidence varies from 0.6% to 1.3%. Conventional angiography is a commonly used modality for the assessment of coronary artery anomalies, but it may not identify and define the anatomy of anomalous arteries due to the complexity of the course and three-dimensional orientation of the arteries. We present a rare case of duplicated right coronary artery (RCA) with separate ostium on 64-row multidetector computed tomography (MDCT). MDCT is better than conventional angiography in cases where selective catheterisation of either a single artery or ostium during catheter angiography has resulted in missing an important vessel. So far, 13 cases of duplicated RCA have been reported in the literature, and the features on MDCT were described only in three cases.