VIRTUAL REALITY BASED THREE-DIMENSIONAL GUIDE WIRE PROPAGATION SIMULATION FOR ENDOVASCULAR INTERVENTION

The virtual reality based motion simulation of the guide wire and the catheter inside specific vascular structures can benefit a lot for the endovascular intervention. A fast and well-performed collision cancellation algorithm is proposed based on the geometric analysis and the angular propagation （AP）, and a 3-D real-time interactive system is developed for the motion simulation of the guide wire and the catheter inside the specific patient vascular. The guide wire or the catheter is modeled as the ＂multi-body＂ representation and properties are defined by its intrinsic characteristics. The motion of the guide wire or the catheter inside the vascular is guided by the collision detection and the collision cancellation algorithm. Finally, a relaxation procedure is used to achieve more realistic status. Experimental results show that the behavior of the guide wire or the catheter depends on the defined parameters. The real-time simulation can be achieved. The result shows that the simulation system is effective and promising.

FEM model for real-time guide wire simulation in vasculature

A model suitable for describing the mechanical response of thin elastic objects is proposed to simulate the deformation of guide wires in minimally invasive interventions. The main objective of this simulation is to provide doctors an opportunity to rehearse the surgery and select an optimal operation plan before the real surgery. In this model the guide wire is discretized with the multi-body representation and its elastic energy derivate from elastic theory is a polynomial function of the nodal displacements. The vascular structure is represented by a tetrahedron mesh extended from the triangular mesh of the artery, which can be extracted from the patient＇s CT image data. The model applies the energy decline process of the conjugate gradient method to the deformation simulation of the guide wire. Experimental results show that the polynomial relationship between elastic energy and nodal displacements tremendously simplifies the evaluation of the conjugate gradient method and significantly improves the model＇s efficiency. Compared with models depending on an explicit scheme for evaluation, the new model is not only non-conditionally stable but also more efficient. The model can be applied to the real-time simulation of guide wire in a vascular structure.

Open Surgical Insertion of Tenkchoff Straight Catheter Without Guide Wire

Objective To compare the clinical outcomes of open surgical peritoneal dialysis catheter （PDC） insertion with guide wire and the outcomes of PDC insertion without guide wire. Methods Data of the patients receiving open surgical Tenkchoff straight catheter insertion in our department from January 2005 to January 2011 were retrospectively analyzed. The 117 patients in whom PDC insertion was conducted with the guidance of guide wire were enrolled into group A, and the 121 cases receiving PDC insertion without guide wire were enrolled into group B. The incidences of post-operative complications （catheter obstruction, catheter displacement, bloody dialysate, and dialysate leakage）, catheter survival, and patient survival rates were compared between the 2 groups. Results The baseline characteristics （gender, age, body mass index, prothrombin time, activated partial thromboplastin time, platelet count, serum creatinine, follow-up time, primary diseases, and outcomes） of the 2 groups were comparable （all P〉0.05）. In post-operative complications, only the incidence of early bloody dialysate showed significant difference, being 16.2% in group A and 7.4% in group B （P=0.04）. Catheter and patient survival rates were not significantly different between the two groups. Overweight patients showed a higher incidence of catheter obstruction compared with normal weight patients [16.0% （4/25） vs. 3.3% （7/213）, P=0.02], but no differences in post-operative between the 2 groups. complications were found among overweight patients Conclusions Open surgical Tenkchoff straight catheter insertion without guide wire does not lead to higher risk of post-operative complications and catheter removal. It may be an alternative option when guide wire is not available.

Influence on Visibility Due to Differences of Guide Wire Movement―Visual &Physical Evaluations

The visibility of moving images during cardiac catheterization and treatment may be reduced by a number of factors. First, it involves multiple movements that occur simultaneously, such as the movements due to the heart beat and movement of the guide wire used during the treatment. There is also the influence of the X-ray dose on the image quality in the X-ray output. If X-rays are irradiated onto moving objects such as a guide wire moving during treatment of the heart, cardiac catheterization may be displaced to the next image recorded even when an insufficient X-ray dose has been irradiated because the imaged object is moving during the time the X-rays are emitted (pulse width). If the X-ray dose planned to be irradiated to the target is low, there is also the possibility that noise will appear in the image, and the imaged object may be lost in noise and visibility be reduced. For this reason, we conducted basic research into how changes in the speed of rotation of guide wires affect visibility when wires are positioned horizontally and vertically, using a dynamic phantom and recorded X-ray moving images. The purpose of this study is to elucidate whether the deterioration in the visibility is affected by the X-ray dose, the orientation or movement of a guide wire, or caused by other conditions, in order to contribute to improving the visibility in the X-ray moving images. The results showed a lower visual evaluation only in the vertical direction at the more rapid movement here, but this did not result in significant changes in the physical evaluation. This suggests that the structure and characteristics of the human eyes would be involved, as human vision is stronger with lateral movements and weaker with vertical movements due to the arrangement of the human eyes, side by side. Findings from this basic study can be utilized to improve the visibility in the X-ray moving images by paying attention to the observation environment of the observer of the X-ray moving images. In addition, the findings of this study can also be used to determine protocols for improving visibility in X-ray moving images, such as adjusting the X-ray dose in an X-ray device when further improvement is required. Therefore, this study was able to provide suggestions to contribute to the development of improved visibility of X-ray moving images.

One case of guide wire fracture and retention in child＇s internal jugular vein puncture

Central venous catheterization was a common technology in clinical anesthesia and rescue. Guide wire fracture and retention was a very rare and severe complication in central venous catheterization. Here, we reported a case that guide wire was broken and remained in the body in internal jugular vein puncture process in an 8-year-old boy.

Choice PTTM guidewire for recanalization of total occlusive coronary arteries

Objective: To evaluate the therapeutic effects of 0. 014' Choice PTTM wire in chronic total occlusion angioplasty. Methods: Balloon angioplasty was attempted in 25 arteries with chronic total occlusion, with the mean time of occlusion of 17±13 months (ranging from 2 to 84 months) and mean length of 14±6 mm (ranging from 5 to 25 mm). The morphology of the lesions included bridging collaterals (4 cases), calcification (3 cases) and major side branch at the lesion (4 cases) . Choice PT?wire was used electively in all the cases. Results: Lesion was crossed successfully in 92% (23/25) cases, without incidences of dissection of the coronary artery with subintimal entry. Balloon angioplasy and stenting (n = 21) were performed with good immediate angiograghic results. Acute myocardial infarction or death occurred in none of the patients. Conclusion Successful recanalization of chronic coronary total occlusions using Choice PTTM wire can be achieved with good safety.

Treated With Retrograde Guide Wire Technique:A Case Report

Chronic total occlusion （CTO） of coronary artery accounts for 10 % - 20 % in coronary intervention cases. It is the most challenging coronary artery disease at present and is regarded as the most difficult issue for intervention doctor. Herein, we report a case in a 55-year-old woman with right coronary artery opening total occlusion who was treated with retrograde guide wire technique.

Novel economic treatment for coronary wire perforation:A case report

BACKGROUND Coronary artery perforation is a rare but potentially life-threatening complication of percutaneous coronary intervention(PCI),however if recognized and managed promptly,its adverse consequences can be minimized.Risk factors include the use of advanced PCI technique(such as atherectomy and chronic total occlusion interventions)and treatment of severely calcified lesions.Large vessel perforation is usually treated with implantation of a covered stent,whereas distal and collateral vessel perforations are usually treated with embolization of coils,fat,thrombin,or collagen.We describe a novel and cost-effective method of embolisation using a cut remnant of a used angioplasty balloon that was successful in sealing a distal wire perforation.we advocate this method as a simple method of managing distal vessel perforation.CASE SUMMARY A 73-year-old male with previous coronary Bypass graft operation and recurrent angina on minimal exertion had undergone rotablation and PCI to his dominant left circumflex.At the end of the procedure there was evidence of wire perforation at the distal branch and despite prolonged balloon tamponade there continued to be extravasation and the decision was made to seal this perforation.A cut piece of an angioplasty balloon was used and delivered on the original angioplasty wire to before the perforation area and released which resulted in sealing of the perforation with no unwanted clinical consequences.CONCLUSION The use of a balloon remnant for embolization in coronary perforation presents a simple,efficient and cost-effective method for managing coronary perforations and may be an alternative for achieving hemostasis and preventing poor outcome.Prevention remains the most important part with meticulous attention to the distal wire position,particularly with hydrophilic wires.

Removal of a pulmonary artery foreign body during pulse ablation in a patient with atrial fibrillation:A case report

BACKGROUND Foreign bodies in the pulmonary circulation have been documented in the literature and are typically caused by interventional procedures.However,reports of pulmonary artery foreign bodies during femoral vein puncture are rare,and there is no description of this complication from the guidewire surface flows into the pulmonary artery during a pulse ablation in a patient with atrial fibrillation.CASE SUMMARY We described a case in which a linear foreign body suddenly appeared on fluoroscopy image during pulsed ablation of atrial fibrillation.Multiposition angiography showed that the foreign body was currently lodged in the pulmonary artery but was hemodynamically stable.We then chose to use an interventional approach to remove the foreign body from the pulmonary artery.This foreign body was subsequently confirmed to be from the hydrophilic coating of the guidewire surface.This may be related to the difficulties encountered during the puncture of the femoral vein.This is a rare and serious complication of femoral vein puncture.Therefore,we reported this case in order to avoid a similar situation.CONCLUSION Mismatches between interventional devices from different manufacturers used for femoral venipuncture may result in pulmonary artery foreign bodies.

Evaluation of a new method for placing nasojejunal feeding tubes

AIM:To compare fluoroscopic, endoscopic and guide wire assistance with ultraslim gastroscopy for placement of nasojejunal feeding tubes. METHODS:The information regarding nasojejunal tube placement procedures was retrieved using the gastrointestinal tract database at Tongji Hospital affiliated to Tongji Medical College. Records from 81 patients who underwent nasojejunal tubes placement by different techniques between 2004 and 2011 were reviewed for procedure success and tube-related outcomes. RESULTS:Nasojejunal feeding tubes were successfully placed in 78 (96.3%) of 81 patients. The success rate by fluoroscopy was 92% (23 of 25), by endoscopic technique 96.3% (26 of 27), and by guide wire assistance (whether via transnasal or transoral insertion)100% (23/23, 6/6). The average time for successful placement was 14.9 ± 2.9 min for fluoroscopic placement, 14.8 ± 4.9 min for endoscopic placement, 11.1 ± 2.2 min for guide wire assistance with transnasal gastroscopic placement, and 14.7 ± 1.2 min for transoral gastroscopic placement. Statistically, the duration for the third method was significantly different (P < 0.05) compared with the other three methods. Transnasal placement over a guidewire was significantly faster (P < 0.05) than any of the other approaches. CONCLUSION:Guide wire assistance with transnasal insertion of nasojejunal feeding tubes represents a safe, quick and effective method for providing enteral nutrition.