Guidewire Tip Research Articles

Svelte™ Acrobat Stent-on-a-Wire Coronary Stent System

Direct stenting may reduce local vessel trauma, minimise ‘geographical miss’, prevent distal embolisation and save time/money during percutaneous coronary interventions. However, direct stenting is currently performed in ≤50% of most cathether laboratories worldwide. Among the main reasons to pre-dilate, vessels anatomy (tortuosity and amount of calcification) play a central role in the operator’s decision. The recently developed Acrobat Stent-On-A-Wire (SOAW) coronary system combines a very thin (81μ) L605 CoCr stent mounted on a delivery system with a 0.012-inch integrated guidewire tip (distance from the tip of the wire to the stent is 22mm). This is a balloon-expandable stent and the nylon balloon is also directly mounted onto the wire. The Acrobat SOAW may potentially facilitate percutaneous coronary intervention by reducing time/cost and minimising peri-procedural complications and therefore benefit a large number of patients in daily practice who are currently labelled as unfavourable for direct stenting.

Fatal hemorrhage after attempted treatment of a basilar artery stenosis

Interventional treatment of severe intracranial stenoses using angioplasty and stent placement carries a significant risk of severe adverse events. These events are frequently caused by the intraarterial dilation but may also be precipitated by other causes related to the procedure. The authors describe a fatal subarachnoid hemorrhage during the treatment of a basilar artery (BA) stenosis caused by a vascular rupture distant from the site of angioplasty. After successful balloon dilation, an attempt to deploy a self-expanding stent failed due to the severe kinking of the stenotic segment of the BA. The angiogram performed during the intervention revealed a fatal rupture of the BA in a location not related to the angioplasty or guide wire tip. The technical aspects of the intervention are analyzed on the basis of the postmortem findings.

Delayed presentation of lateral femoral circumflex artery injury post cannulated hip screw surgery – a case report

An elderly patient underwent cannulated hip screw surgery for a subcapital neck of femur fracture. Nine days post surgery, she was noted to have collapsed with a falling haemoglobin level. Computed tomography revealed a large haematoma to the thigh. Further angiography showed active bleeding from one of the branches of the lateral femoral circumflex artery (LFCA), which we postulate was caused by the sharp tip of a version guidewire used during fracture fixation surgery. Iatrogenic injury during hip fracture fixation is a rare event, particularly to the circumflex branches of the profunda femoris artery (PFA), and may occur from hard wire use intra-operatively or from the fracture itself. The LFCA branches laterally from the PFA, runs anterior to the femoral neck, where we suspect it was injured in our case. Whilst a version wire is a useful radiological guide intra-operatively, manually clearing a passage for its insertion into the femoral head/neck junction and using the blunt end is recommended. A combination of acute swelling in the operated region and falling haemoglobin post surgery should alert the clinician to possible vascular injury. Compared to duplex ultrasonography, CT angiography remains the gold standard in its specificity and sensitivity for diagnosing arterial injuries. With early recognition and prompt radiological intervention, this rare complication of fracture fixation surgery can be treated without the need for further surgery.

Guidewire Tip Detachment during Stent-Assisted Coiling of an Intracranial Aneurysm

Endovascular treatment of complex intracranial lesions often requires use of two different microcatheters or micro-guidewires. A basilar artery aneurysm was treated with microstent-assisted coiling. During the procedure a microwire severed and the distal platinum portion of the wire was left after unsuccessful attempts to retrieve it. The patient remains asymptomatic. The proximal part of the microwire was analyzed and additional experiments indicate that it may have detached by electrolytic corrosion.

Recanalization of chronic peripheral artery occlusions: Moving forward by looking sideways

Chronic peripheral artery occlusions can be challenging to recanalize. Two general strategies are prevalent, and neither is necessarily under the direct control of the operator. In the classic (and in my opinion favored) “centriluminal” technique, the operator attempts to direct guidewires in tandem with controlling catheters to traverse the occlusive atheroma while remaining within the confines of the arterial media. The second technique, inaptly called the “subintimal” approach [1,2], in some ways resembles a controlled perforation in both ease and (in my opinion) attractiveness. The guidewire traverses the occlusion by entering a shallow subadventitial plane using a large guidewire “knuckle” and afterwards can reenter the patent distal arterial lumen. In both techniques, conventional imaging usually provides few robust cues about the true course of the guidewire within the occlusion. In this issue, Kawasaki and colleagues [10] report their experience assuring an intraluminal guidewire trajectory using adjunctive intravascular ultrasound (IVUS) imaging. They take advantage of a new low-profile hydrophilic 0.018*Prime; guidewire (not available in the United States) and generous tolerances apparently afforded by a 0.014*Prime;-rated commercial phased-array IVUS catheter. They use the IVUS catheter as their support device. In the Kawasaki centriluminal approach, the side-looking IVUS device is advanced over the guide-wire step-by-step to assure an appropriate intraluminal position. When the position appears subadventitial, both the IVUS and the guidewire are retracted and redirected before advancing again. Unfortunately, this technique identifies an unsuitable position only in retrospect, since the IVUS device is oriented not forwards but sideways, and the ultrasound transducer is positioned at least 10–15 mm proximal to the guidewire tip. Such retrospective image guidance is analogous to driving through a tunnel watching only the side windows, hoping the front of the car passes or crumples safely. Fortunately in the Kawasaki experience, peripheral artery occlusions were fairly forgiving, in that short distances of unfavorable subadventitial axial advancement of the devices appeared well-tolerated. The authors report a significantly improved success rate and reduced iodinated radiocontrast exposure, although not procedure time or radiation exposure. Other adjuncts are available to enhance conventional radiographic guidance of iliofemoral CTO recanalization, including optical interferometry [3], ultrasound-guided needle lumen reentry [4], wholly external Duplex ultrasound guidance [5] for infrainquinal procedures, and fusion of tomographic and fluoroscopy imaging [6]. More promising future technologies might include forward-looking intravascular ultrasound [7,8] or perhaps better, conducting the entire recanalization procedure under real-time MRI guidance [9] to assure wholly intraluminal guidewire traversal. That said, Kawasaki and colleagues enhance our toolbox for safe guidewire traversal of chronic peripheral artery occlusions. This requires little or no capital outlay for most laboratories and a small incremental procedure cost. We still await better solutions to assure long-term patency once peripheral revascularization is complete.

Transected Guidewire Tip Simulating Ureteral Stone

A 62-year-old woman was admitted with a diagnosis of a distal ureteral stone 2 years after antegrade imaging of the kidney. Ureteroscopy revealed a guidewire tip that transected during the antegrade study. The events leading to guidewire transection were reproduced, and a minor modification of current guidewires is suggested to prevent similar incidents.

Magnetic Guide-Wire Navigation in Pulmonary and Systemic Arterial Catheterization: Initial Experience in Pigs

Cardiovascular catheterization can be challenging whenever a stenosis or an abnormal vascular course interferes with probing the target vessel. This study addresses the feasibility of navigating a guide wire with a magnetic tip by an external magnetic field through pulmonary and systemic arteries in an experimental porcine model. We investigated six piglets using magnetic guide-wire navigation. Two pulmonary arteriograms were taken from different angles in order to reconstruct the three-dimensional vessel anatomy. A computer interface then calculated three-dimensional coordinates for the vessel in space. Using these coordinates, two external magnets were positioned to create magnetic vectors along the expected vessel course. Magnetically enabled guide wires were then navigated into the vessels using the magnetic field to orient the guide-wire tips. Aortic and renal branches were addressed in a similar fashion. Difficulty in reaching the target vessel was reflected by the number of attempts that were necessary. After 10 failed attempts, the maneuver was recorded to have failed. Thirty-five of 37 (94.6%) arteries with branches at acute angles were reached successfully using magnetic navigation. In two pigs, the left upper lobe artery could not be probed. Peripheral arteries of small diameter were easier to reach than large central arteries, requiring less attempts. Magnetic guide-wire navigation is feasible in the arteries of the lungs, the head and neck, and the kidneys. It is particularly useful in entering small arterial branches at acute angles and may facilitate interventional therapy in a variety of vascular diseases in children and adults.

Development of Computer-Based Simulator for Catheter Navigation in Blood Vessels (2nd Report, Evaluation of Torquability of Guidewire)

We have developed catheter simulation system in blood vessels for surgical planning and intraoperative assistance. In this study, we evaluated the torquability of the guidewire model for the simulation system. The model of the guidewire is constructed with viscoelastic springs and segments as the dynamic deformation of a flexible structure. The vessel is an elastic circular cylinder, whose shape is defined by the centerline and the radii. Collisions between the guidewire and the vessel are calculated and the contact forces are determined according to the stiffness and friction of the vessel wall. Using these models, the trajectory of the guidewire tip was calculated when the proximal part of the guidewire model was twisted at a constant speed. When the friction coefficient between the guidewire and the vessel is large, the guidewire tip vibrates. When the guidewire is twisted, there is a lag before the guidewire tip starts rotating and friction obstructs this rotation. Besides the friction coefficient, the shape of the blood vessel also affects the motion of the guidewire tip. When the guidewire becomes stiffer, the torquability of guidewire tip increases. This simulator would be useful for the analysis of the structure of the guidewire and may help guide the design of new guidewire.

Pulmonary Atresia With Intact Ventricular Septum. Perforation and Pulmonary Vavuloplasty Using a Modified Mechanical Technique. Medium-Term Follow-Up

In patients with pulmonary atresia with intact ventricular septum (PAIVS), radiofrequency-assisted perforation of the valve is the most widely used initial therapy when the anatomy is favorable. We report our experience with a modified mechanical technique that gave good results. Between November 2001 and October 2006, valve opening was carried out successfully in 11 consecutive neonates with a favorable anatomy (i.e., Alwi groups A and B, and tricuspid valve Z-score -1.1 [1.3]). The technique involved snare-assisted anterograde or retrograde perforation with the soft tip of a special guidewire used for chronic total coronary artery occlusions, use of an arteriovenous loop, and progressive balloon dilatation from a diameter of 2 mm to a maximum diameter of 9.6 [1.2] mm. Valve opening was achieved in all patients, and right ventricular (RV) systolic pressure fell from 97 [17] mmHg to 48 [13] mmHg (P< .001). No pericardial effusion or cardiac tamponade was observed, though one neonate died 24 hours after the procedure due to pulmonary embolism. Six patients (54%) were discharged without any further intervention, while 4 (36%) required an additional increase in pulmonary blood flow. During the follow-up period of 25 [21] months, two patients died. Eight (72%) survived and were in New York Heart Association functional class 1. Two required additional surgery on the outflow tract, one of whom also needed a one-and-a-half ventricular repair. Data indicate that the valves remain open as RV structures grow, though without any change in the tricuspid valve Z-score. Pulmonary valvuloplasty using a mechanical technique proved effective in patients with PAIVS. Modification of the standard mechanical technique by using the soft tip of a special guidewire used for chronic total coronary artery occlusions was less aggressive and improved results. In patients with a favorable anatomy, results were comparable to those obtained using the radiofrequency technique.

The Usefulness of Intracoronary Electrocardiography during Primary Percutaneous Coronary Intervention in Patients with Acute Myocardial Infarction

Background and Objectives：Measurements obtained using an intracoronary electrocardiogram (IC-ECG) reflect the electrical activity in various regions of the myocardium. This technique can be easily used in the catheterization laboratory during percutaneous coronary intervention (PCI) procedures. Furthermore, IC-ECG could be used to evaluate myocardial viability in patients with acute myocardial infarction (AMI). The aim of this study was to evaluate the usefulness of IC-ECG in predicting the microvascular integrity and late improvement of left ventricular (LV) function after primary PCI in patients with AMI. Subjects and Methods：A total of 78 patients (62 male, 16 female) who underwent primary PCI with stent implantation were enrolled in this study. After the implantation of the stent, IC-ECG was recorded from the tip of an insulated angioplasty guidewire before and after balloon occlusion of the infarct-related artery. The IC-ECG was obtained from the inferior and inferolateral areas in inferior wall MI, or apex and apical anterior wall regions in anterior wall MI. Significant ST segment elevation was defined as a further ST segment elevation of ≥0.2 mV at 80 msec after the J-point in comparison to the baseline value. The microvascular integrity of the myocardium was evaluated by myocardial contrast echocardiography (MCE) one day after the PCI was performed. Six months later, all of the patients were followed up by echocardiography and the wall motion score index (WMSI) and ejection fraction (EF) were measured. Results：Significant ST elevation was noted in 47 patients (Group A) after coronary occlusion. There was no significant change in the other 31 patients (Group B). MCE showed microvascular perfusion in 41 patients in group A (87%) and in four patients in group B (13%) (p<0.05). The six-month follow-up echocardiography showed that group A had a lower WMSI (1.20±0.18 vs 1.56±0.34, p<0.05) and higher EF (57.6±7 vs 47±11, p<0.05) than group B. The LV end diastolic dimension (LVEDD ) in group B was increased compared to group A (p=0.021). The LV end systolic dimension (LVESD ) was also increased in group B; however, the LVESD in group A was decreased after six months (p=0.002). Conclusion： IC-ECG during PCI is a simple and useful method for assessing the microvascular integrity of the myocardium and for predicting the long-term improvement of LV function. (Korean Circulation J 2007;37:148-153)

Magnetic versus manual guidewire manipulation in neuroradiology: in vitro results

Standard microguidewires used in interventional neuroradiology have a predefined shape of the tip that cannot be changed while the guidewire is in the vessel. We evaluated a novel magnetic navigation system (MNS) that generates a magnetic field to control the deflection of a microguidewire that can be used to reshape the guidewire tip in vivo without removing the wire from the body, thereby potentially facilitating navigation along tortuous paths or multiple acute curves. The MNS consists of two permanent magnets positioned on either side of the fluoroscopy table that create a constant precisely controlled magnetic field in the defined region of interest. This field enables omnidirectional rotation of a 0.014-inch magnetic microguidewire (MG). Speed of navigation, accuracy in a tortuous vessel anatomy and the potential for navigating into in vitro aneurysms were tested by four investigators with differing experience in neurointervention and compared to navigation with a standard, manually controlled microguidewire (SG). Navigation using MG was faster (P=0.0056) and more accurate (0.2 mistakes per trial vs. 2.6 mistakes per trial) only in less-experienced investigators. There were no statistically significant differences between the MG and the SG in the hands of experienced investigators. One aneurysm with an acute angulation from the carrier vessel could be navigated only with the MG while the SG failed, even after multiple reshaping manoeuvres. Our findings suggest that magnetic navigation seems to be easier, more accurate and faster in the hands of less-experienced investigators. We consider that the features of the MNS may improve the efficacy and safety of challenging neurointerventional procedures.

Is Magnetic Resonance Image Guidance the Key to Opening Chronic Total Occlusions?

Through progressive plaque growth or fibrotic organization of occlusive thrombus, atherosclerosis may result in chronic total occlusion (CTO) of a major arterial conduit. If CTO develops slowly, collateral pathways may supply sufficient perfusion to retain tissue viability despite occlusion of the major inflow conduit. However, such collateral-mediated perfusion rarely matches that provided by an open main conduit, particularly during the peak demand of regional muscular activity. Although strategies to limit regional oxygen demand (eg, β-blockers for the treatment of angina pectoris) or to enhance collateral function (eg, a walking program for superficial femoral occlusion, experimental angiogenesis) may be of some benefit, these approaches generally offer less complete return of normal physiology and relief of ischemic symptoms than does direct revascularization of the occluded vessel. With surgical bypass, the nature of the occlusion (its length, duration, tortuosity, calcification) is less important than the presence of a suitable distal anastomotic target. On the other hand, with catheter-based techniques, success depends heavily on these lesion characteristics. In fact, crossing such occluded segments with a guidewire remains the dominant barrier to catheter-based treatments of occluded arterial segments. Once the guidewire has been passed successfully into the distal true lumen, the process of dilating and stenting the segment is usually straightforward and durable, at least with the use of drug-eluting stents in coronary CTOs.1,2 Article p 1101 Devices designed to cross CTOs should have 3 key features: an ability to distinguish a true luminal path from one created within (dissection) or through (perforation) the vessel wall of the occluded segment, an ability to change direction (steer) to correct deviations from the desired path through the occlusion, and an ability to penetrate the frequently fibrotic and focally calcific substance of the occlusion through the use of either mechanical stiffness or an alternative energy modality (laser, …

Ventricular Tachycardia Originating from the Epicardium Identified by Intracoronary Mapping Using a PTCA Guidewire

We report a case in which endocardial radiofrequency (RF) ablation guided by unipolar intracoronary mapping using a guidewire was an effective therapy for treating VT originating from an epicardial site of the left ventricle. A 55-year-old man with dilated cardiomyopathy was referred for treatment of refractory sustained monomorphic VT. The earliest unipolar electrogram with a near-perfect pace map was identified at segment #8 of the left anterior descending artery utilizing a guidewire through a microtube catheter during the VT. VT was terminated by an endocardial RF application at an upper midventricular septal site that did not have a good pacemap or the earliest electrogram, and that was the most adjacent anatomical endocardial site to the guidewire tip. No VT was clinically observed during a follow up period of 14 months.

Development of a safe guidewire

As the result of a locking phenomenon that may occur in a guidewire inside a metal puncture needle when using the Seldinger technique to insert a central venous catheter, the guidewire can break and cause an embolism. To counter this possibility we devised a guidewire with a structure that made it difficult for locking to occur and compared it to conventional guidewires. Conventional guidewires are wound lengthways with a spring. The improved version has a special multi-ply structure. A series of 100 cases were divided into two groups: group A, the conventional guidewire group; and group B, the improved guidewire group. We punctured the internal jugular vein and attempted insertion of the guidewire through the side hole of a 22-gauge metal needle. We then compared the frequency of locking and the frequency of bending of the guidewire tips that have been withdrawn. In group A, locking occurred in 72% of the cases where the guidewire was unable to be inserted, but this figure was 0% in group B. The improved guidewire has the advantage of reducing the risk of locking and of guidewire breakage.

Development of Computer-based Simulator for Catheter Navigation in Blood Vessels (1st Report, Evaluation of Fundamental Parameters of Guidewire and Blood Vessel)

We have developed catheter simulation system in blood vessels for surgical planning and intraoperative assistance. In this study, we evaluated the effect of the fundamental parameters of the guidewire and blood vessel models for the simulation system. The model of the guidewire was constructed with viscoelastic springs and segments to avoid complicated mathematical procedures as the dynamic deformation of a flexible structure. The vessel is an elastic circular cylinder, whose shape is defined by the centerline and the radii. Collisions between the guidewire and the vessel are calculated and the contact forces are determined according to the stiffness, damping and friction of the vessel wall. Using these models, the trajectory of the guidewire tip and the reaction force were calculated. When friction coefficient between the guidewire and the vessel is large, the guidewire tip vibrates. When deformation property of the vessel is changed, the trajectory of guidewire tip also changes. Bending of the guidewire tip decreases the reaction force at bending points of the vessel. When the guidewire becomes stiffer, the deformation of the vessel becomes large. These findings should facilitate determination of the parameters of the simulation system.

A polymer‐based MR‐compatible guidewire: A study to explore new prospects for interventional peripheral magnetic resonance angiography (ipMRA)

To introduce a newly developed polymer-based and magnetic resonance (MR)-compatible guidewire and to explore its capabilities with respect to interventional peripheral magnetic resonance angiography (ipMRA) in a flow phantom. The guidewire is based on a polyetheretherketone (PEEK) polymer core, and small iron particles are embedded in its coating. A passive device tracking technique was designed utilizing a susceptibility artifact induced by the wire in images acquired with a balanced steady-state free precession (b-SSFP) sequence using small flip angles. The position of the guidewire tip was determined from image intensity maxima and overlayed onto a roadmap in near real-time. Guidewire tracking and balloon angioplasty of an artificial stenosis were attempted in two configurations of a flow phantom. Successful passive guidewire tracking was performed for all phantom configurations. Robustness and accuracy of the tracking technique were sufficient for phantom studies. A balloon catheter was placed into the stenosis using the guidewire under complete MR guidance, and subsequent balloon angioplasty yielded improved flow conditions. The new guidewire is well-suited for clinical application due to an absence of the risk of core fracture and its atraumatic flexible tip. It opens novel prospects for the realization of ipMRA in humans that need to be explored in further studies.

Venture wire control catheter

We wished to test the safety and efficacy of a novel wire control catheter for use during percutaneous coronary intervention. The ability to vary the angulation of the tip of an intravascular guidewire would often be desirable. Previous attempts to produce deflectable-tip guidewire systems have met with limited success. The Venture wire control catheter (Velocimed, Minneapolis, MN) was used to facilitate percutaneous coronary intervention in 20 patients. There were no device-related complications. Percutaneous coronary intervention was successful in all patients. Our initial experience with the Venture wire control catheter has been favorable.

Influence of orientations of guidewire tip on the placement of subclavian venous catheters

The role of a J-type guidewire tip has been known to prevent vascular or cardiac wall damage. We hypothesized that the course of the guidewire may be influenced by the initial orientations of the J-type guidewire tip during the subclavian approach. The purpose of this study was to investigate the influence of the direction of the needle bevel and J-wire tip on successful placement of subclavian catheters. A total of 140 adult patients of either sex were studied. Patients were randomly divided by the direction of the needle bevel (neutral vs. downward) and the direction of the J-wire tip (upward vs. downward). Under general anesthesia, right infraclavicular subclavian catheterization was attempted using the Seldinger technique. There was no statistically significant difference among the successful and unsuccessful placements in relation to factors including sex, body mass index, and needle bevel direction. The success rate was high when the J-wire tip was directed downward (P = 0.001). These data suggest that the orientation of the J-wire tip downward can increase successful placement rates of right subclavian venous catheterization.

Guide wire navigation and therapeutic device localization for catheterization procedure

The objective of the present research is to develop a system for precise real-time localization of a guide wire tip and therapeutic device in order to provide assistance in guide wire navigation and accurate device deployment within the coronary arteries with minimal contrast material injection. The goal is achieved by real time monitoring of the guide wire tip and therapeutic device in a sequence of fluoroscopic images and automatic registration to the 3D model of the artery.

Cardiac Perforation Complicated by Cardiac Tamponade and Sealed With Metallic Coils

Distal coronary artery perforation with an angioplasty guidewire is a rare complication that may cause cardiac tamponade, myocardial infarction, arrhythmia, and even death. The use of platelet IIb/IIIa glycoprotein receptor inhibitors increases the risk of potentially fatal complications that are difficult to manage. We report a patient on treatment with abciximab who presented coronary perforation in a distal branch of the right coronary artery caused by the coronary guidewire tip, and complicated by acute cardiac tamponade. Blood extravasation to the pericardium was stopped by releasing two metallic coils into the distal vessel, thereby avoiding the need for emergent cardiac surgery.