Dimitri Aerden

Heavily calcified arterial lesions are difficult to treat in an endovascular manner with conventional techniques due to limited arterial compliance. Intravascular lithotripsy offers a novel minimally invasive therapeutic option through endovascular emission of acoustic waves, fracturing calcium deposits and facilitating lesion dilation. We present the case of a successful application of the Shockwave intravascular lithotripsy system (IVL®, Shockwave Medical Inc) in a heavily calcified stenosis of the right renal artery in a patient with a coral reef aorta.

Objective/Background: Carotid artery stenting (CAS) is a valuable solution for the treatment of carotid artery stenosis in a high-risk patient population for carotid endarterectomy (CEA). In literature however, there are concerns about the death and stroke rates of CAS in the 'real world' practice. Since Belgium is a small country with a broad offer of medical care, and there is no reimbursement for CAS, only small numbers of patients can be treated per vascular department. Methods: In our department 45 CAS were performed from January 2006 until May 2018. Patient characteristics, indication for treatment and choice of treatment, minor stroke, major stroke and death rates were analyzed retrospectively. Results: Of these patients 8/45 (18%) had a symptomatic carotid artery stenosis and 37/45 (82%) had an asymptomatic stenosis. A total minor stroke rate of 3/45 (6.6%) was recorded, but no major stroke (0%) or death (0%). Of the 37 patients who were asymptomatic at the start, 1 suffered a minor stroke (1/37, 2.7%) peri-operatively. Conclusion: Real world data from a low volume center show that CAS performed in patients with high risk for CEA yields acceptable outcome that is comparable to the literature. Since CAS is a delicate procedure we advice to centralize the procedure to an dedicated experienced interventionalist and to perform rigorous quality control of your 'real world' data.

In recent years, there has been an increasing interest in replacing digital subtraction angiography (DSA) as method of choice for the diagnostic imaging of patients suffering from lower extremity peripheral arterial disease (PAD). Due to small vessel diameters and suboptimal resolution, examinations of below-the-knee arteries however remain extremely challenging. The advent of wide beam CT scanners allows to perform multiple CT acquisitions over a wide patient volume. A sequence of these CT acquisitions at timed intervals could provide additional hemodynamic information, and as such allows to track a contrast bolus that propagates through the arterial conduit. The aim of this study was to evaluate the accuracy and precision of ow velocity measurements using time-resolved computed tomography angiography (CTA). To this end, we constructed a mechanical ow phantom (single lumen, 6 mm inner-diameter). Six consecutive time-resolved CTA acquisitions were performed at a constant ow rate to achieve six reference velocities (21.2 mm/s, 38.9 mm/s, 60.1 mm/s, 81.4 mm/s, 99.0 mm/s and 120.3 mm/s). The mean centerline ow velocity was obtained from the contrast propagation over three different segmental lengths (160 mm, 80 mm and 40 mm) and then compared to the reference ow velocity. The results of this study suggest that mean ow velocities within the range of typical blood ow velocities in the below-the-knee arteries (40 mm/s - 70 mm/s), can be accurately measured with high precision in a 6 mm ow phantom using time-resolved CTA when considering a minimal path length of 80 mm.

Background: There are few data to inform decisions about the optimal management of occluded tunneled cuffed hemodialysis catheters with thrombolytic locking solutions. The effect of dose, dwell-time, and number of administrations remains controversial. Methods: In this retrospective single-center review of tunneled cuffed catheters used between 2010 and 2014, restoration of blood flow as well as pre- and post-pump pressures after either short (30 min) or prolonged (48–72 h) administration of 100,000 IU of urokinase locking solution was evaluated in all thrombotic dysfunctions. We also assessed if multiple urokinase locks for the same thrombotic dysfunction event were more efficient to restore catheter performance than single administration. Results: Data on 773 thrombotic events in 148 patients (236 catheters) were collected during observation period. After urokinase treatment, blood flow and pre-pump pressure improved (median of 50 mL/min and 20 mmHg) whereas post-pump pressure decreased (median of 15 mmHg) (all P < 0.0001). The short thrombolytic procedure, used in more severely dysfunctional catheters, resulted in significantly larger improvements in catheter function than the long procedure. Multiple administrations for the same thrombotic event further improved access function in case of persisting dysfunction after first lock but had no added beneficial effect if blood flow and/or pump pressures were normalized after first urokinase lock. Conclusion: Both short and prolonged administration of urokinase locks were efficient in restoring blood flow and pre- and post-pump pressures in dialysis catheters with thrombotic dysfunction. Multiple urokinase locks provide added benefit on these outcomes only in case of persisting dysfunction after the first lock.