Pericardial tamponade after superior vena cava stent: are nitinol stents safe?

Numerical modelling of the interaction between dialysis catheter, vascular vessel and blood considering elastic structural deformation

The dialysis catheter indwelling in human bodies has a high risk of inducing thrombus and stenosis. Biomechanical research showed that such physiological complications are triggered by the wall shear stress of the vascular vessel. This study aimed to assess the impact of CVC implantation on central venous haemodynamics and the potential alterations in the haemodynamic environment related to thrombus development. The SVC structure was built from the images from computed tomography. The blood flow was calculated using the Carreau model, and the fluid domain was determined by CFD. The vascular wall and the CVC were computed using FEA. The elastic interaction between the vessel wall and the flow field was considered using FSI simulation. With consideration of the effect of coupling, it was shown that the catheter vibrated in the vascular systems due to the periodic variation of blood pressure, with an amplitude of up to 10% of the vessel width. Spiral flow was observed along the catheter after CVC indwelling, and recirculation flow appeared near the catheter tip. High OSI and WSS regions occurred at the catheter tip and the vascular junction. The arterial lumen tip had a larger effect on the WSS and OSI values on the vascular wall. Considering FSI simulation, the movement of the catheter inside the blood flow was simulated in the deformable vessel. After CVC indwelling, spiral flow and recirculation flow were observed near the regions with high WSS and OSI values.

Cardiac tamponade after superior vena cava stenting

Superior vena cava (SVC) syndrome results from the blockage of venous blood flow through the SVC, which is caused by either internal obstruction (eg, thrombus) or external compression (eg, thoracic malignancy and infection).1 While thrombus-related SVC syndrome is rising in prevalence, malignancy still accounts for the majority of cases.1 Regardless of cause, SVC syndrome is characterised by facial swelling and plethora, headache and dyspnoea.2 Although venous stenting has become standard of care for treatment of acute SVC syndrome, stent placement presents multiple risks including SVC rupture and cardiac tamponade. In these cases, a high index of suspicion and prompt action are required to avoid an often fatal outcome. Here, we present the case of a patient with cardiac tamponade and subsequent cardiac arrest after SVC stent placement.

Palliative treatment of superior vena cava syndrome with nitinol stents

This study aims to retrospectively evaluate the outcomes following nitinol stent placement for malignant superior vena cava syndrome. A total of 25 patients with thoracic malignancies were treated with self-expanding nitinol stents for superior vena cava syndrome (E*Luminexx [Bard GmbH/Angiomed, Karlsruhe, Germany], Sinus-XL [OptiMed Medizinische Instrumente GmbH, Ettlingen, Germany], and Zilver Vena [Cook Medical Inc., Bloomington, IN]). It was seen that the procedural success rate was 76% with all stents deployed as intended and no procedure-related complications but in five patients with 50% residual stenosis and one patient with stent occlusion within 48 hours after stent deployment. Stent occlusion occurred in further two patients during follow-up: one patient developed infection, thrombosis, and occlusion in the stent seen at 2-month follow-up, and one patient had stent occlusion at 4-month follow-up. The clinical success rate was 96%. Stent compression leading to a greater than 50% reduction in stent diameter was observed in three patients at follow-up. Overall 22 patients died at a mean follow-up of 3.5 months for reasons related to their underlying malignancy. It was concluded that the stent treatment for superior vena cava syndrome is a safe treatment with good clinical effect in patients with superior vena cava syndrome in the terminal phase of malignant disease. In this small patient population, no trends were observed which would suggest that outcomes vary by stent type, though additional, large-scale studies are needed.