Use Of Guidewire Research Articles

Katheterassoziierte Komplikationen bei der Peritonealdialyse – Infektiöse und nicht infektiöse Komplikationen sowie Prophylaxe

Katheterassoziierte Infektionen sind eine wichtige Ursache für einen Wechsel von Peritonealdialysepatienten zur Hämodialyse. Eine Frühdiagnose dieser Infektionen und einer eventuellen Tunnelbeteiligung (mittels Sonografie des Kathetertunnels) sind ebenso wichtig wie eine rechtzeitige adäquate Therapie. Schmerzen beim Dialysatein- oder -auslauf können durch vorzeitigen Abbruch des Dialysatauslaufes, Umstellung auf Tidal-Peritonealdialyse oder Wechsel zu biokompatibleren Dialyselösungen behandelt werden. Bei Dialysatauslaufproblemen kann man zunächst Laxanzien und Antiflatulenzien verabreichen und die Patienten können im Falle einer Katheterdislokation gymnastische Übungen durchführen. Bei einer persistierenden Fehllage des Katheters ist eine Relokalisation mittels Führungsdraht oder Laparoskopie oder ein Wechsel des Katheters notwendig. Beim Auftreten eines Dialysatlecks an der Katheteraustrittsstelle sollte man die Peritonealdialyse unterbrechen. Sie kann meist nach ein paar Tagen mit reduziertem Füllvolumen oder nach der Umstellung auf eine automatisierte Peritonealdialyse fortgeführt werden. In seltenen Fällen ist eine kontinuierliche Drainage der Peritonealhöhle oder eine chirurgische Revision (besser Katheterwechsel) notwendig. Die Erfahrung des Peritonealdialyseteams und des Chirurgen sind aus prophylaktischer Sicht für das Katheterüberleben bedeutender als das verwendete Kathetermodell oder die Implantationsmethode. Eine korrekte Anlage der Austrittsstelle und die Patientennachschulung bezüglich des Verbandswechsels haben eine große Bedeutung. Aktuelle Guidelines empfehlen die tägliche Anwendung einer antibiotischen Salbe an der Peritonealdialysekatheter-Austrittsstelle.

O-006 A novel microcatheter based device for endovascular mechanical thrombectomy/flow restoration

PurposeTo evaluate the performance of a new microcatheter based device (ReStore, Reverse Medical, Irvine, California, USA) for endovascular mechanical thrombectomy/flow restoration in a swine thromboembolic model and to compare its...

A realistic elastic rod model for real-time simulation of minimally invasive vascular interventions

Simulating intrinsic deformation behaviors of guidewire and catheters for interventional radiology (IR) procedures, such as minimally invasive vascular interventions is a challenging task. Especially real-time simulations for interactive training systems require not only the accuracy of guidewire manipulations, but also the efficiency of computations. The insertion of guidewires and catheters is an essential task for IR procedures and the success of these procedures depends on the accurate navigation of guidewires in complex 3D blood vessel structures to a clinical target, whilst avoiding complications or mistakes of damaging vital tissues and blood vessel walls. In this paper, a novel elastic model for modeling guidewires is presented and evaluated. Our interactive guidewire simulator models the medical instrument as thin flexible elastic rods with arbitrary cross sections, treating the centerline as dynamic and the deformation as quasi-static. Constraints are used to enforce inextensibility of guidewires, providing an efficient computation for bending and twisting modes of the physically-based simulation model. We demonstrate the effectiveness of the new model with a number of simulation examples.

ERCP cannulation and sphincterotomy devices

The American Society for Gastrointestinal Endoscopy (ASGE) Technology Committee provides reviews of existing, new, or emerging endoscopic technologies that have an impact on the practice of GI endoscopy. Evidence-based methodology is used, with a MEDLINE literature search to identify pertinent clinical studies on the topic, and a MAUDE (Food and Drug Administration Center for Devices and Radiological Health) database search to identify the reported complications of a given technology. Both are supplemented by accessing the "related articles" feature of PubMed and by scrutinizing pertinent references cited by the identified studies. Controlled clinical trials are emphasized, but, in many cases, data from randomized controlled trials are lacking. In such cases, large case series, preliminary clinical studies, and expert opinions are used. Technical data are gathered from traditional and Web-based publications, proprietary publications, and informal communications with pertinent vendors. Technology Status Evaluation Reports are drafted by 1 or 2 members of the ASGE Technology Committee, reviewed and edited by the committee as a whole, and approved by the governing board of the ASGE. When financial guidance is indicated, the most recent coding data and list prices at the time of publication are provided. For this review the MEDLINE database was searched through February 2009 for articles related to cannulation and sphincterotomy devices by using the keywords ERCP, standard catheter, sphincterotome, cannulation, sphincterotomy, precut, major papilla, minor papilla, needle-knife, complication, pancreatitis, biliary, and pancreatic in different search term combinations. Technology Status Evaluation Reports are scientific reviews provided solely, for educational and informational purposes. Technology Status Evaluation Reports are not rules and should not be construed as establishing a legal standard of care or as encouraging, advocating, requiring, ordiscouraginganyparticulartreatmentorpayment for such treatment.

In-Hospital Outcomes of Contemporary Percutaneous Coronary Intervention in Patients With Chronic Total Occlusion: Insights From the J-CTO Registry (Multicenter CTO Registry in Japan)

Our aim was to investigate in-hospital outcomes of percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) using contemporary techniques. Despite its increasing popularity and technical complexity, clinical outcomes of PCI for CTO using contemporary techniques have not been adequately evaluated. The J-CTO registry (multicenter CTO registry in Japan) is a large scale, multicenter registry enrolling consecutive patients undergoing PCI for CTO from 12 Japanese centers. In-hospital clinical outcomes were evaluated in 498 patients with 528 CTO lesions. Multiple wiring strategies were frequently attempted (parallel wiring 31% and retrograde approach 25%) with relatively long guidewire manipulation time (median 30 min). Utilizing these complex strategies, high procedural success rates (88.6% in the first attempt cases and 68.5% in the retry cases) were accomplished. In-hospital adverse event rates were strikingly low (cardiac death 0.2%, Q-wave myocardial infarction 0.2%, and stroke 0%). Potential disadvantages of these procedures, including a large amount of contrast volume (median 293 ml) and long fluoroscopic time (median 45 min), were not associated with serious clinical sequelae (contrast induced nephropathy 1.2% and radiation dermatitis 0%). Although coronary perforations were documented frequently by angiography (antegrade 7.2% and retrograde 13.6%), clinically significant perforation resulting in cardiac tamponade was rare (0.4%). Most CTO lesions can be safely and successfully treated with PCI utilizing contemporary advanced techniques. Invasiveness and potential risks of these strategies, which have been the greatest concerns of CTO treatment, may be acceptable in the majority of cases considering the actual incidences of related adverse events and the procedural success rates.

A Prospective Randomized Study Comparing Tenckhoff Catheters Inserted using the Triple Incision Method with Standard Swan Neck Catheters

The downward directed exit of the swan neck catheter may decrease the risk of exit-site infection (ESI). The percentage of migrations of the swan neck catheter seems to be less than the conventional Tenckhoff catheter and the swan neck catheter is more expensive and cannot be manipulated by guidewire technique if tip migration occurs. In this study, the conventional Tenckhoff catheter was used. The straight tunnel was converted to an arcuate one using the triple incision method, resulting in a downward directed exit. The arcuate tunnel was created by passing the catheter through an additional incision located between the paramedian incision and the exit site. We compared the infective and mechanical complications of the Tenckhoff catheter with a downward exit, implanted using the triple incision method, with the swan neck catheter. 101 new peritoneal dialysis patients were prospectively randomized to receive either the Tenckhoff catheter with a downward exit, implanted using the triple incision method, or the swan neck catheter. Each patient was followed up for 24 months. 50 patients were in the triple incision method group (TIMG) and 51 were in the swan neck catheter group (SNCG). Over a mean period of 18.9 +/- 8.0 months of follow-up, ESI occurred in 35 patients (70%) in TIMG and 37 patients (72.5%) in SNCG (p = 0.83). The ESI rates were 0.71 and 1.0 episodes/catheter-year in TIMG and SNCG respectively (p = 0.21). The peritonitis rates were similar in the 2 groups (0.64 episodes/year in TIMG and 0.68 episodes/year in SNCG, p = 0.47). More patients in TIMG had tip migration [15 patients (30%) in TIMG vs 10 patients (19.6%) in SNCG] but the difference was not statistically significant. Repositioning of the catheter by guidewire manipulation was successful in patients in TIMG but not in SNCG. Overall catheter survival at 12 and 24 months was 95% and 83% in TIMG and 93% and 79% in SNCG respectively (p = 0.72). By using the conventional Tenckhoff catheter with a downward exit created using the triple incision method, high catheter survival rates with infective and mechanical complication rates similar to those of the swan neck catheter can be achieved. The triple incision method has the additional advantages of lower cost and the catheter can be manipulated by guidewire technique if tip migration occurs.

Real-time Seldinger technique simulation in complex vascular models

Commercial interventional radiology vascular simulators emulate instrument navigation and device deployment, though none supports the Seldinger technique, which provides initial access to the vascular tree. This paper presents a novel virtual environment for teaching this core skill. Our simulator combines two haptic devices: vessel puncture with a virtual needle and catheter and guidewire manipulation. The simulation software displays the instrument interactions with the vessels. Instruments are modelled using a mass-spring approximation, while efficient collision detection and collision response allow real time interactions. Experienced interventional radiologists evaluated the haptic components of our simulator as realistic and accurate. The vessel puncture haptic device proposes a first prototype to simulate the Seldinger technique. Our simulator presents realistic instrument behaviour when compared to real instruments in a vascular phantom. This paper presents the first simulator to train the Seldinger technique. The preliminary results confirm its utility for interventional radiology training.

Correction of displaced peritoneal dialysis catheters with an angular stiff rod

Fluoroscopically guided guidewire manipulations are readily available and inexpensive methods of correcting malfunctioning peritoneal dialysis catheters, with reported success rates ranging from 25% to 67%. To improve the success rates of guidewire manipulations with a modified technique. Using a stiff rod and a stiff wire under fluoroscopy guidance, catheters that had migrated were drawn back into the rectovesical pouch. An angular rod was used to lever the catheter downward, and the guidewire was used to push the catheter down. No complications developed, and immediate success was achieved in 13 of 14 interventions. With this technique, catheter patency in chronic ambulatory peritoneal dialysis (CAPD) patients (11/12) was higher than that of previously reported methods. Durable success was maintained in nine of 12 patients after a single intervention. All re-manipulations (2/2) were successful. Although used in only 14 interventions in 12 patients, the outcome was promising. This method is a safe and favorable alternative to other guidewire manipulations, based on absence of complications and high success.

Atherosclerotic Peripheral Vascular Disease Symposium II

The primary goal of this American Heart Association renal intervention writing group was to discuss current controversies related to renal interventions and to recommend important areas of clinical research and advocacy initiatives in this peripheral arterial bed. The 4 areas covered in this section include (1) management of asymptomatic renal artery disease, (2) treatment of ischemic nephropathy, (3) prevention and treatment of atheroembolism in renal artery interventions, and (4) treatment of renal in-stent restenosis (ISR). Atherosclerotic renal artery disease is an often unrecognized contributor to refractory hypertension, renal insufficiency, and increased risk of cardiovascular death.1,2 Renal artery disease is associated with increased cardiovascular events (myocardial infarction, stroke, and death), and when associated with symptomatic coronary artery disease, it independently doubles the risk of death.3 Additionally, the presence of bilateral renal artery stenoses is associated with a reduced 4-year survival rate when compared with unilateral disease (47% versus 59%, P <0.001).3 Hypertension, renal insufficiency, and multisystem atherosclerosis are common entities, and the independent occurrence of these conditions is frequent. Thus, the physician must distinguish between association and causation in the evaluation of patients with atherosclerotic renal artery disease and critically appraise the potential for clinical improvement in selecting patients for renal artery intervention. In contrast to other regional manifestations of atherosclerosis, it is impractical to classify patients with atherosclerotic renal artery disease into symptomatic or asymptomatic categories. Two of the cardinal manifestations of renal artery disease, hypertension and renal insufficiency, are frequently “silent” with regard to clinical manifestations until end-organ damage or uremia occurs. Thus, the majority of patients may be deemed asymptomatic. A more appropriate classification of patients with atherosclerotic renal artery disease may be to classify them in relation to potential clinical consequences. We propose the following classification scheme in patients with renal artery disease:

Abstract 2514: Endovascular Imaging Causes Significant But Temporary Endothelial Injury

Coronary Imaging e.g. IVUS and OCT to assess vascular size, plaque morphology and composition are useful tools in clinical trials as well as in routine practice. It is unclear whether imaging catheters induce acute endothelial cell damage (ECD) and how this heals over time. Methods. Normal porcine coronary arteries were subjected to intravascular imaging (Raman, IVUS, OCT), guidewire-only placement or no manipulation (control). ECD was assessed acute or at 5 days (chronic) with an Evans Blue dye-exclusion test and planimetry followed by scanning electron microscopy (SEM). Results. Acute injury (% staining of the area exposed to imaging) was considerable, but similar for the 3 imaging catheters. Guidewire-only induced less ECD. One-way ANOVA showed that only OCT- and RAMAN induced more ECD than control. Analysis with SEM showed that staining was associated with either EC denudation or injured but present EC. At 5 days staining was reduced to background levels. Conclusion. Vascular imaging and guide wire manipulation both induce acute ECD, but this injury heals within 5 days following imaging. Planimetry of endothelial injury

Over-the-catheter precut to gain access to the biliary duct during ERCP rendezvous

Endoscopic retrograde cholangiopancreatography (ERCP) rendezvous during laparoscopic cholecystectomy is an efficient and safe method to treat cholecystocholedocholithiasis. Advancing a guidewire through the cystic duct into the duodenum and withdrawing it in the accessory channel of duodenoscope may be, however, laborious. Moreover, rendezvous performed in the typical manner needs the use of several costly accessories. We herein describe a simpler and cheaper method to gain access to the biliary duct at rendezvous. Twenty-four consecutive patients undergoing ERCP rendezvous during laparoscopic cholecystectomy were considered. A catheter was introduced in the cystic duct and advanced into the duodenum. Access to the bile duct was than achieved by means of a precut sphincterotomy performed over the catheter emerging from the papilla. Cannulation was successful in all but two patients, in whom ERCP was performed in the conventional manner. The only complication was a case of mild post-sphincterotomy bleeding. In comparison with the typical rendezvous technique our procedure allowed savings of about <euro>250, since its performance only requires a catheter and a knife sphincterotome. Over-the-catheter precut during ERCP rendezvous is a feasible and safe method which avoids the need for the manipulation of several accessories and guidewires, and thus results in money and time savings.

Cystic duct remnant mucocele in a liver transplant recipient

Cystic duct remnant mucocele is an extremely rare complication of liver transplantation in children. Surgical correction is usually required for cystic duct remnant mucocele when it causes biliary obstruction. We describe a 14-month-old liver transplant recipient who presented with biliary obstruction 1 month after orthotopic liver transplantation with an end-to-end choledochocholedocal biliary anastomosis for hepatoblastoma. US, CT and cholangiography findings were consistent with mucocele of the allograft cystic duct remnant. Surgery was not needed in our patient because the mucocele and biliary obstruction had resolved on repeat imaging most likely due to guidewire manipulation during cholangiography, resulting in opening of the cystic duct remnant orifice and drainage into the common duct.

Transcatheter ductal stenting in critical neonatal Ebstein's anomaly

Symptomatic neonatal Ebstein's anomaly shows a very poor outcome, most frequently due to duct-dependent pulmonary circulation caused by functional pulmonary valve atresia. In this setting, percutaneous ductal stenting using high-flexibility coronary stents might be a highly cost-effective alternative to systemic-to-pulmonary shunt. Three newborns (age 4.7 +/- 2.9 days; weight 3.0 +/- 0.3 kg) with critical, duct-dependent tricuspid valve Ebstein's anomaly and functional pulmonary atresia unresponsive to prostaglandin infusion and multidrug vasodilator therapy, underwent duct stabilization with high-flexibility, open-cell stents as an alternative to surgical palliation. Their echocardiographic picture predicted a very high mortality rate. In two cases, the ductus arteriosus was recanalized using a combined pharmacological (local prostaglandin infusion) and mechanical (hydrophilic coronary guide-wire manipulation) approach. Stent implantation increased duct diameter from 0.5 +/- 0.7 to 3.2 +/- 0.2 mm (P < 0.0001), resulting in a significant rise in oxygen saturation from 67 +/- 9 to 92 +/- 4% (P < 0.00001). After the procedure, the patients were quickly weaned from mechanical ventilation and discharged after 16 +/- 7 days. Uneventful spontaneous ductal closure ensued in two patients in a few months, and percutaneous oxygen saturation was 87 +/- 3% at the last follow-up session (12 +/- 10 months). In critical newborns with severe, duct-dependent Ebstein's anomaly unresponsive to medical therapy, ductal stenting could be a reliable, safe and cost-effective alternative to either long-term prostaglandin treatment or surgical palliation, in view of lower-risk corrective surgery at older age. This option may also be attempted successfully within a few days of spontaneous ductal closure using a combined pharmacological and mechanical approach.

Tunneled Central Venous Catheter Malpositioning

Laureys and Rommens have recently described their experience with the spontaneous repositioning of a tunneled central venous catheter post injection of contrast medium [1]. We would like to add an experience we had with the malpositioning of a catheter and describe a further means of avoiding this complication. The authors described catheter misplacement in the right internal mammary vein and reported an overall catheter mislocation incidence of 0% to 4% [2]. They felt that conventional anteroposterior (AP) fluoroscopy (as recommended for checking correct position) would not have avoided incorrect positioning in this case. The authors have now changed their practice and inject hypo-osmolar contrast medium to ensure correct catheter placement. At our institution we have had similar experience with catheter malposition in the azygos system, also appearing correctly placed on AP fluoroscopy. We have subsequently modified our practice to ensure correct catheter placement by initial guidewire manipulation through the right atrium and down the inferior vena cava (IVC) to its bifurcation. We believe that if the guidewire can be advanced with ease to this position, it can only be in the IVC, thus ensuring appropriate proximal catheter placement without the need for iodinated contrast medium injection. Since adoption of this technique at our institution we have had no incidence of catheter misplacement, and furthermore, complicated venous anatomy is identified at an early stage of the procedure at which stage contrast venography can be performed if required. In conclusion, we agree that systematic injection of hypo-osmolar contrast medium is a more reliable method of ensuring correct catheter placement than simply relying on AP fluoroscopy. However, we feel that the simple technique of initial guidewire manipulation into the distal IVC ensures proper proximal catheter placement without the utilization of iodinated contrast medium.

Successful Management of Catheter Obstruction by Endoscopic Naso-Pancreatic Drainage Tube

Editor: We present a case of catheter obstruction successfully relieved using an endoscopic naso-pancreatic drainage (ENPD) tube, normally used for drainage of pancreatic or biliary juice. A 60-year-old non-obese female with end-stage renal disease was introduced to peritoneal dialysis. A Tenck- hoff catheter was placed under general anesthesia in her left lower abdomen where no omentum was detected, and the exit was placed at the other side of the lower abdomen. Two months later, she suddenly experienced complete absence of outflow. Attempt for recovery by suction and injection of saline and urokinase failed, thus open surgery was conducted, revealing epiploic appen- dices of the sigmoid colon incarcerated tightly into the side hole closest to the exit of the catheter, probably operating like a check valve. The fat was pulled out of the side hole, and the catheter was re-placed in the pel- vic cavity. However, similar drainage failure recurred 2 weeks later. To avoid reoperation, manipulation under fluoroscopy was considered. First we determined the site of obstruction by infusing contrast media, which revealed probable obstruction at the previous site. Relieving the incarceration by guidewire manipulation was unsuccess- ful as the fat seemed to be firmly incarcerated. Presum- ing further wire manipulation would be difficult or even dangerous, we slowly squeezed the guidewire beyond the obstruction site so as not to protrude the catheter. A 5Fr ENPD tube, the maximum diameter that would slide into the catheter, was placed further than the obstruction site over the guidewire. The guidewire was pulled out, leaving the ENPD tube behind where it could be exam- ined through the transparent catheter. Subsequently, drainage failure has not recurred and sufficient drain- age with the ENPD tube stationed in the same position has been maintained for over 5 months.

Prospective Study of Operator-Controlled Guidewire Cannulation of the Bile Duct

Bile duct (BD) access during ERCP is usually achieved by contrast injection (CI) and/or assistant-directed guidewire cannulation (GWC). Short wire biliary catheters now allow the operator to control guidewire manipulations during ERCP. The aim of this prospective study was to evaluate the efficiency and safety of operator-controlled GWC when only BD cannulation is intended. Methods: BD cannulation was attempted in all cases using a hydrophilic tipped guidewire controlled by the endoscopist. Contrast was injected after GWC of the BD or when needed to help achieve BD cannulation. Access sphincterotomy (precut) was usually performed if repeated unintentional PD cannulations occurred. Data collected included ERCP indication, BD GWC success and need for CI, unintentional pancreatic duct (PD) GWC or CI, cannulation difficulty, and complications. Cannulation difficulty was graded as: easy (1-4 attempts & < 5 min), moderate (5-10 attempts & < 10 min), difficult, or precut. Results: From 996 ERCPs performed between 5/2004 and 11/2006, 398 patients without prior endotherapy underwent attempted operator-controlled GWC. GWC of only the BD was intended in 223 patients. Indications for ERCP were: abnormal liver tests (n = 135), abnormal intraoperative cholangiogram (n = 43), pain (n = 23), biliary pancreatitis (n = 12), or other (n = 10). Successful BD cannulation was achieved in 220 (99%) cases. GWC of the BD was achieved before any CI in 114 (51%). CI was needed in 48 and precut was performed in 58. Unintentional PD cannulation occurred in 110 (49%) cases with only GWC of the PD in 28 and PD GWC + PD CI in 82. BD cannulation difficulty and post-procedure complication data according to whether the PD was cannulated are found in Tables 1 & 2. One case of mild post-ERCP pancreatitis occurred after operator-controlled unintentional PD GWC without CI. Conclusions: 1) Operator-controlled GWC of the BD is most often easily obtained but unintentional PD cannulation still occurs about half the time. 2) Attempted GWC of the BD is associated with an acceptable risk for post-ERCP complications but is most safe when PD cannulation is completely avoided. Table 1Operator-controlled biliary GWC difficulty according to PD cannulation Cannulation difficulty Easy Moderate Difficult Precut Failed No PD cannulation (n = 113) 85 17 3 7 1 Unintentional PD (n = 110) 19 27 11 51 2 Total (n = 223) 104 44 14 58 3 Open table in a new tab Table 2Post-procedure complications Pancreatitis Perforation Other complications No PD cannulation (n = 113) 0 0 1 (pain) Unintentional PD (n = 110) 5 (4.5%) 1 (0.9%) 1 (bleed) Total ERCP (n = 996) 20 (2%) 7 (0.7%) 21 Open table in a new tab

Impact of a bidirectional approach via radial and popliteal arteries for the treatment of chronic total occlusion of lower limb artery: A case report

A 49-year-old man with poorly controlled diabetes was admitted to Kushiro Rosai Hospital, Hokkaido, Japan after scalding both feet with boiling water. Because of poor healing, he was assessed for peripheral arterial disease. Angiography revealed total occlusion of the right common and external iliac arteries, diffuse stenosis of the right superficial femoral artery, focal stenosis of the left common iliac artery and chronic total occlusion of the left superficial femoral artery. A staged procedure with bidirectional approach via the radial and popliteal arteries was attempted. During the procedures, the patient was in the prone position on the catheterization table, and bidirectional guidewire manipulation was performed. All of the lesions were successfully stented. The patient was not required to change positions during the procedure, which can be performed by a single operator. The bidirectional approach is effective in the setting of transcatheter treatment of chronic total occlusive disease.

Initial Experience Using a Forward Directed, High‐Intensity Focused Ultrasound Balloon Catheter for Pulmonary Vein Antrum Isolation in Patients with Atrial Fibrillation

A high-intensity-focused ultrasound balloon catheter (HIFU-BC) is designed to isolate pulmonary veins (PV) outside the ostia (PV antrum). This catheter uses a parabolic CO2 balloon (behind water balloon) to focus a 20-, 25-, or 30-mm diameter ring of ultrasound forward of the balloon (parallel to catheter shaft). The purpose of this study is to test the safety and efficacy of the HIFU-BC for PV antrum isolation in patients with atrial fibrillation (AF). Twenty-seven patients with paroxysmal (19 patients) or persistent (8 patients) AF were studied. Double transseptal puncture was performed for left atrial deployment of a Lasso catheter (for PV mapping) and the 14 Fr HIFU-BC. The HIFU-BC was positioned outside the PV orifice over a guidewire. HIFU energy (acoustic power 45 watts) was applied for 40 seconds with a 20-mm sonicating ring and 40 or 60 seconds with a 25-mm or 30-mm sonicating ring. No other ablation system was utilized. PV antrum isolation was attempted using HIFU-BC in 78 of 104 PVs (25/27 RSPVs, all 23 LSPVs, all 23 LIPVs, all four left common trunks and 3/27 RIPVs). HIFU-BC successfully isolated 68 (87%) of the 78PV antra with 1-26 (median 3) HIFU applications. The complications include transient bleeding from a distal branch of the left superior PV resulting from guidewire manipulation in one patient and right phrenic nerve injury in another patient. No PV stenosis (>50% narrowing) and no LA-esophageal fistula occurred. At the 12-month follow-up, 16 (59%) of the 27 patients were free of symptomatic episodes of AF (only 3 of the 16 patients were receiving antiarrhythmic medications). Forward-focused HIFU applications isolated PVs outside the PV ostium with elimination of AF in 16 (59%) of the 27 patients at 12 months following the single ablation procedure.

Robustness and complexity of a minimally invasive vascular intervention simulation system

Minimally invasive vascular interventions offer advantages over open surgery. Thorough training is needed to master the skills required to correctly perform these minimally invasive interventions. Simulation is becoming a potential alternative for training. We have developed the foundation, i.e., the algorithmics and models, for a minimally invasive vascular intervention simulation system focusing on guide-wire manipulations. In this article we address the robustness, accuracy, and complexity of this foundation using a phantom. To this end the theory on which the simulation is based is used to formulate constraints on the simulation parameters. Furthermore, the parameter space has been explored in order to optimize the trade-off we are facing: accuracy versus speed of the simulation. A physical experiment setup has been designed that allows us to obtain ground-truth data. The accuracy of the simulation has been determined by comparing physical experimental results with various simulations. For multiple combinations of parameter settings the simulation supplies a guide-wire configuration with a root-mean-square error around 1 mm. The results show that the speed of the simulation is still an issue and needs to be improved. Nevertheless, the results also indicate that the developed algorithms and models are a robust foundation to build a simulation system on.

Iatrogenic Type A Dissection After Attempted Stenting of a Descending Aortic Aneurysm

This case demonstrates an iatrogenic acute retrograde type A dissection of the aortic arch and ascending aorta during elective endovascular stenting of a proximal descending aortic aneurysm. This devastating complication necessitated emergent surgery with unfavorable postoperative outcome. Other than the known causes, the described retrograde type A dissection resulted from guidewire manipulation and iatrogenic creation of a false lumen, which was erroneously dilated and stented.