Assessing the effects of manual dexterity and playing computer games on catheter-wire manipulation for inexperienced operators.

AIM: To investigate the effect of playing computer games and manual dexterity on catheter-wire manipulation in a mechanical aortic model. MATERIAL AND METHODS: Medical student volunteers filled in a preprocedure questionnaire assessing their exposure to computer games. Their manual dexterity was measured using a smartphone game. They were then shown a video clip demonstrating renal artery cannulation and were asked to reproduce this. All attempts were timed. Two-tailed Student's t-test was used to compare continuous data, while Fisher's exact test was used for categorical data. RESULTS: Fifty students aged 18-22 years took part in the study. Forty-six completed the task at an average of 168 seconds (range 103-301 seconds). There was no significant difference in the dexterity score or time to cannulate the renal artery between male and female students. Students who played computer games for >10 hours per week had better dexterity scores than those who did not play computer games: 9.1 versus 10.2 seconds (p=0.0237). Four of 19 students who did not play computer games failed to complete the task, while all of those who played computer games regularly completed the task (p=0.0168). CONCLUSION: Playing computer games is associated with better manual dexterity and ability to complete a basic interventional radiology task for novices.

A comparison of the quality of the information available on the internet on interventional radiology, vascular surgery, and cardiology.

CONTEXT AND AIMS: Internet use is rapidly expanding and increasingly plays a substantial role in patient education. We sought to evaluate and compare the quality of information available to patients online on three closely linked specialties: Interventional radiology (IR), cardiology, and vascular surgery. MATERIALS AND METHODS: We searched the leading three search engines for the terms: "Interventional Radiology", "cardiology," and "vascular surgery," collating the top 50 hits from each search. After excluding duplicates and irrelevant sites, 43, 25, and 36 sites remained, respectively. Sites were analyzed using the LIDA instrument (an online tool for assessing health-related websites) and Fleisch Reading Ease Scores (FRES) were compared across the different search terms and correlated with the country of origin and certification by the Health on the Net (HON) Foundation. RESULTS: There was no significant difference ( P>0.05) in the total LIDA, accessibility, usability or reliability scores between the three specialties. HONCode certification was associated with higher LIDA (83.1±1.6 vs. 71.53±0.8 ( P<0.0001)), reliability (75.7±3.6 vs. 49.0±1.6 ( P<0.0001)) and FRES (37.4±4.0 vs. 29.7±1.4 ( P=0.0441)). CONCLUSION: Websites are generally well designed and easy to use; the majority however, lacks currency and reliability. Despite similarity in quality of online information, there is a disparity in knowledge of IR; this may be due to low web-traffic figures of IR sites. Wikipedia's user-generated content, ranks highly in major search engines, as such; this could serve as means of disseminating reliable health information to patients.

Endovascular repair of an acute, mycotic, ascending aortic pseudoaneurysm.

This report describes endovascular stenting of an acute mycotic ascending aortic aneurysm. An eighty-three year old lady presented nine weeks after aortic valve surgery and subsequent thyroidectomy with sternal pain secondary to a mycotic ascending aortic pseudoaneurysm. The pseudoaneurysm was visible through the unhealed sternum. Open repair was considered too high a mortality risk. Endovascular stenting was performed using two covered infrarenal proximal extension devices (GORE Excluder Aortic Extender(®), W. L. Gore & Associates, Flagstaff, Arizona, USA) deployed from a right axillary approach utilising overdrive cardiac pacing. Post procedure imaging revealed shrinkage of the pseudoaneurysm sac.

Robotically-steerable catheters and their role in the visceral aortic segment.

In recent years, steerable catheter systems have been introduced into clinical practice for cardiac mapping and ablation procedures. As endovascular therapy is becoming more complex, more advanced and versatile catheter designs utilizing robotic technology may have a role in aortic and peripheral arterial interventions. This article discusses alternative steerable catheter designs focusing on robotic endovascular catheter technology. A comprehensive comparison, review and analysis of robotic versus manual techniques in the visceral segment are presented to reveal both their advantages and limitations. Preclinical studies and early experience suggest that robotically steerable endovascular catheters offer improved manoeuvrability at the catheter tip, enhanced positional control and "off-the-wall" centreline navigation in a remote-control fashion. These advanced systems have the potential to overcome some of the technical difficulties with manual catheter control, improve stability at key target areas, reduce the risk of vessel trauma, distal embolization and radiation exposure, whilst improving overall operator performance with short learning curves. Robotic catheter technology may be more suitable to complex and often unpredictable anatomy in the visceral segment and may offer a reliable platform for future applications involving device delivery or target intervention. This intuitive technology is rapidly evolving and still requires technological refinements to extend current capabilities. Clinical studies involving head-to-head comparisons with conventional techniques are essential for evaluating its long-term safety and efficacy.

Analysis of flow patterns in a patient-specific aortic dissection model.

Aortic dissection is the most common acute catastrophic event affecting the thoracic aorta. The majority of patients presenting with an uncomplicated type B dissection are treated medically, but 25% of these patients develop subsequent aneurysmal dilatation of the thoracic aorta. This study aimed at gaining more detailed knowledge of the flow phenomena associated with this condition. Morphological features and flow patterns in a dissected aortic segment of a presurgery type B dissection patient were analyzed based on computed tomography images acquired from the patient. Computational simulations of blood flow in the patient-specific model were performed by employing a correlation-based transitional version of Menter's hybrid k-epsilon/k-omega shear stress transport turbulence model implemented in ANSYS CFX 11. Our results show that the dissected aorta is dominated by locally highly disturbed, and possibly turbulent, flow with strong recirculation. A significant proportion (about 80%) of the aortic flow enters the false lumen, which may further increase the dilatation of the aorta. High values of wall shear stress have been found around the tear on the true lumen wall, perhaps increasing the likelihood of expanding the tear. Turbulence intensity in the tear region reaches a maximum of 70% at midsystolic deceleration phase. Incorporating the non-Newtonian behavior of blood into the same transitional flow model has yielded a slightly lower peak wall shear stress and higher maximum turbulence intensity without causing discernible changes to the distribution patterns. Comparisons between the laminar and turbulent flow simulations show a qualitatively similar distribution of wall shear stress but a significantly higher magnitude with the transitional turbulence model.

The visceral hybrid repair of thoraco-abdominal aortic aneurysms--a collaborative approach.

OBJECTIVE: To report the collaborative data of 3 major European Vascular Units using the 'visceral hybrid' procedure for thoraco-abdominal aortic aneurysms and dissections. METHODS: A consecutive series of 107 urgent and elective high-risk patients were included in a prospectively collected database. RESULTS: All stents involved the entire thoracic and abdominal aorta with left subclavian coverage in 19 and revascularisation in 12. The distal landing zone was in the infra-renal aorta in 75% and in the iliac artery in 25%. The 30-day mortality rate was 16/107 (14.95%). 13/107 (12.1%) of the patients suffered spinal cord ischaemia which was complete and permanent in 9/12 (8.4%). 4 patients (3.7%) required long term dialysis and a segment of gut infarction requiring resection occurred in 3 (2.8%). Most patients had visceral bypass grafting and aortic stent-grafting performed in one stage. In 18 patients the stenting was performed later. Three of these patients ruptured before the stenting procedure was undertaken. CONCLUSION: These early results of visceral hybrid repair for high-risk patients with complex thoraco-abdominal aortic aneurysms are encouraging, in a group of patients in whom fenestrated/branched stent-grafting is not an option and open surgery hazardous.

A Systematic Review of Outcomes Following Percutaneous Transluminal Angioplasty and Stenting in the Treatment of Transplant Renal Artery Stenosis.

PURPOSE: To evaluate outcomes following treatment of transplant renal artery stenosis by percutaneous transluminal angioplasty and stent insertion. MATERIALS AND METHODS: A literature search was performed using Pubmed, MEDLINE, Embase, Wiley Interscience and the Cochrane Library databases. Outcome measures were glomerular filtration rate, creatinine, blood pressure and number of antihypertensive medications. Technical and clinical success, patency and complication rates were also analysed. RESULTS: Thirty-two studies met the inclusion criteria, involving a total of 884 interventions including PTA, stenting, or combinations of both. Clinical success rates were in the range 65.5-94%. The majority of studies reported technical success rates higher than 90%. Patency rates were in the range of 42-100%. However, the definition and diagnostic criteria for TRAS varied widely between studies. Also, marked heterogeneity was observed in the reporting of outcome measures with no consensus in outcome criteria or follow up schedule. CONCLUSION: Outcomes following PTA and stenting for the treatment of TRAS have been shown to be favourable. However, there is a distinct lack of well designed studies assessing outcomes following intervention. Outcome reporting may be improved by the introduction of standardised outcome measures with reporting of outcomes into a multi-centre registry.

Registration of freehand 3D ultrasound and magnetic resonance liver images.

We present a method to register a preoperative MR volume to a sparse set of intraoperative ultrasound slices. Our aim is to allow the transfer of information from preoperative modalities to intraoperative ultrasound images to aid needle placement during thermal ablation of liver metastases. The spatial relationship between ultrasound slices is obtained by tracking the probe using a Polaris optical tracking system. Images are acquired at maximum exhalation and we assume the validity of the rigid body transformation. An initial registration is carried out by picking a single corresponding point in both modalities. Our strategy is to interpret both sets of images in an automated pre-processing step to produce evidence or probabilities of corresponding structure as a pixel or voxel map. The registration algorithm converts the intensity values of the MR and ultrasound images into vessel probability values. The registration is then carried out between the vessel probability images. Results are compared to a "bronze standard" registration which is calculated using a manual point/line picking algorithm and verified using visual inspection. Results show that our starting estimate is within a root mean square target registration error (calculated over the whole liver) of 15.4 mm to the "bronze standard" and this is improved to 3.6 mm after running the intensity-based algorithm.

A randomised prospective comparison of the Flamingo Wallstent and Ultraflex stent for palliation of dysphagia associated with lower third oesophageal carcinoma.

BACKGROUND: Covered metallic oesophageal stents offer effective palliation of malignant oesophageal strictures. However, first generation devices were associated with a high rate of migration, particularly when used in the lower oesophagus. AIM: To compare the rate of complications and palliative effect of two newer covered metallic oesophageal stents. PATIENTS AND METHODS: We performed a prospective randomised study using two of these newer stent designs in the treatment of malignant lower third oesophageal tumours. Fifty three patients with dysphagia due to inoperable oesophageal carcinoma involving the lower third of the oesophagus were randomly selected to receive either a Flamingo covered Wallstent (Boston Scientific Inc., Watertown, Massachusetts, USA) or an Ultraflex covered stent (Boston Scientific Inc.). Dysphagia was scored on a five point scale, recorded before stent insertion, the day after, and at least one month later at follow up. Technical success, early and late complications (perforation, migration, severe gastro-oesophageal reflux, haematemesis, and reobstruction due to tumour overgrowth) were also recorded. RESULTS: In both stent groups, a significant improvement in dysphagia score was seen both the next day post stenting and at late follow up (p<0.05). No significant difference was seen in the improvement in dysphagia between the two groups (p>0.1). The frequency of complications encountered in the two groups was similar. Three patients in the Ultraflex group required two stents at primary stenting. CONCLUSION: The two types of stent are equally effective in the palliation of dysphagia associated with lower third oesophageal malignancy and the complication rates associated with their use are comparable.