Cobra Catheter Research Articles

Percutaneous Transcholecystic Approach for an Experiement of Biliary Stent Placement: An Experimental Study in Dogs

Purpose: To determine, in an experimental study of biliary stent placement, the usefulness and safety of the percutaneous transcholecystic approach and the patency of a newly designed biliary stent. Materials and Methods: A stent made of 0.15-mm-thick nitinol wire, and 10 mm in diameter and 2 cm in length, was loaded in an introducer with an 8-F outer diameter. The gallbladders of seven mongrel dogs were punctured with a 16-G angiocath needle under sonographic guidance, and cholangiography was performed. After anchoring the anterior wall of the gallbladder to the abdominal wall using a T-fastener, the gallbladder body was punctured again under fluoroscopic guidance. The cystic and common bile ducts were selected using a 0.035-inch guide wire and a cobra catheter, and the stent was placed in the common bile duct. Post-stenting cholangiography was undertaken, and an 8.5-F drainage tube was inserted in the gallbladder. Two dogs were followed-up and sacrificed at 2, 4, and 8 weeks after stent placement, respectively, and the other expired 2 days after stent placement. Follow-up cholangiograms were obtained before aninmal was sacrificed, and a pathologic examination was performed. Results: Stent placement was technically successful in all cases. One dog expired 2 days after placement because of bile peritonitis due to migration of the drainage tube into the peritoneal cavity, but the other six remained healthy during the follow-up period. Cholangiography performed before the sacrifice of each dog showed that the stents were patent. Pathologic examination revealed the proliferation of granulation tissue at 2 weeks, and complete endothelialization over the stents by granulation tissue at 8 weeks. Conclusion: Percutaneous transcholecystic biliary stent placement appears to be safe, easy and useful. After placement, the stent was patent during the follow-up period.

Profound reduction in brain embolization using an endoaortic baffle during bypass in swine

Background. Cerebral embolization during cardiopulmonary bypass is an important cause of neurologic injury. This study determined whether an endoaortic baffle catheter (Cardeon Cobra Catheter; Cardeon Corporation, Cupertino, CA) could substantially reduce cerebral embolization in a swine cardiopulmonary bypass model. Methods. Sixteen 60 kg pigs underwent cardiopulmonary bypass; 8 animals with the Cobra baffle (Cardeon Corporation, Cupertino, CA) deployed, and 8 with the same cannula without baffle deployment. The animals were embolized with 72,000 fluorescent microspheres (97 to 100 μm) at normothermia. At the end of the experiment, the brains were removed and microspheres were isolated from eight regions. Results. During embolization, the two groups were equivalent with regard to pump flow, mean arterial pressure, temperature, Hgb and PaCO 2. Deployment of the Cobra baffle reduced embolization to every brain region. Deployment of the baffle reduced total brain embolization by 89%. There was a mean of 61 ± 60 emboli per gram in the control animals and 7 ± 24 emboli per gram in those animals in which the baffle was deployed. Conclusions. Cerebral embolization is profoundly reduced by use of the Cobra baffle aortic cannula. The application of this device may reduce postcardiac surgical neurologic injury.

Transurethral Exchange of Double-J Ureteral Stent Using Goose-Neck Snare

Purpose: To evaluate the usefulness of transurethral exchange of double-J ureteral stent as an effective alterna-tive to the cystoscopic approach. Materials and Methods: There were 20 exchange cases involving seven patients (six women and one man) who initially underwent antegrade manipulation of a double-J ureteral stent. Indications for stent placement were ureteral stricture caused by malignancy in six patients [cervical carcinoma (n=5), stomach carcinoma (n=1) ], and renal tuberculosis in one. An 8-F Nelaton catheter was inserted in the bladder via the urethra and contrast material was injected until the bladder was fully distended. The distal end of a double-J ureteral stent was ex-tracted to the urethral orifice using a goose-neck snare and a 0.035 ″stiff guide wire was then advanced to the renal pelvis through the stent. After that, the stent was removed and a 4-F Cobra catheter was advanced to the renal pelvis along the guide wire. Contrast material was injected through the catheter, and the renal pelvis, calyx and ureter were opacified. The 0.035 ″stiff guide wire was again inserted via the catheter, a new double-J ureteral stent was inserted, and the catheter removed. Finally, the new double-J stent was properly located within the renal pelvis and the bladder. Results: Double-J ureteral stents were successfully exchanged in 19 of 20 exchange cases. After the procedure, all patients reported tolerable, minimal lower abdominal pain. Conclusion: Transurethral exchange of double-J ureteral stent is a useful alternative to cystoscopy.

A new technique for endomyocardial biopsy in infants and small children

Endomyocardial biopsy (EMB) is usually performed from the femoral veins in infants and small children. This requires the use of a long vascular sheath to direct a bioptome to the ventricular septum. We describe a technique of EMB in this population that obviates the need for the use of a long vascular sheath. A 5 Fr 0.038" internal diameter, no-sideholes Cobra catheter (Cook, Bloomington, IN) introduced via a 5 Fr short sheath was used to direct a 3 Fr, 60-cm-length Cook bioptome to the ventricular septum. From January 1998 to August 1999, this technique was used 22 times in seven patients for EMB (median, age 13 months; range, 1-72 months). Indications for EMB in this group were posttransplantation surveillance (21 times) and evaluation for cardiomyopathy/myocarditis (1). Median number of EMB specimens obtained per procedure was 6 (range, 5-9). There was one pneumopericardium seen post-EMB with this technique without hemodynamic embarrassment. EMB in infants and small children can be performed successfully, safely, and repeatedly from the femoral veins without the need for a long sheath.

Uterine arteries: bilateral catheterization with a single femoral approach and a single 5-F catheter--technical note.

In 197 patients, uterine embolization with a single femoral approach and a single 5-F cobra catheter was successful in 362 of 394 (92%) uterine arteries. In six patients (12 arteries), distal embolization with a coaxial 3-F microcatheter was safer. In 10 patients with a life-threatening condition, embolization was performed at the anterior division of both internal iliac arteries. Bilateral selective embolization of the uterine arteries can be performed with a single catheter.

Treatment of Hemobilia with Selective Hepatic Artery Embolization

To evaluate retrospectively the results of selective transcatheter embolization in the treatment of hemobilia. Twelve patients with hemobilia (mean age, 43 years) underwent embolotherapy. Causes of hepatic vascular injury were iatrogenic trauma, blunt external trauma, septic emboli, and lupus vasculitis. A 5-F cobra catheter or a 5-F non-tapered Simmons shaped catheter passed over a hydrophilic guide wire, or a Tracker 18 catheter forming a coaxial system was used. Embolic agents included gelatin sponge or polyvinyl alcohol fragments used alone or with coils. Hepatic artery pseudoaneurysms were found in 10 patients, ruptured hepatic artery aneurysm was found in one, and arterioportal fistula was found in two (with pseudoaneurysm in one). Bleeding was immediately controlled in 11 of 12 patients after embolization; one patient rebled and underwent surgery. Two patients underwent repeat embolization (2 weeks and 2 months later). Two patients died, one of biliary sepsis and liver insufficiency 24 hours after embolization and the other of gangrenous cholecystitis. Transcatheter embolization is an effective treatment of hemobilia. It allows control of bleeding and identification of the origin of the hemorrhage.

The Use of a Cystoscopically Placed Cobra Catheter for Directed Irrigation of Lower Pole Caliceal Stones During Extracorporeal Shock Wave Lithotripsy

As the general experience with extracorporeal shock wave lithotripsy (ESWL*) for renal calculi broadens, it is increasingly evident that the clearance of stone fragments in lower pole calices needs to be improved. The stone-free rate after treatment for lower caliceal stones is consistently less than that for other upper tract locations. Use of a cystoscopically placed cobra catheter for directed irrigation during ESWL resulted in an increase of our lower caliceal stone-free rate at 1 and 3 months of followup to 71% (15 of 21) compared to 33% (8 of 24) of randomly selected controls at 1 month and 54% (13 of 24) at 3 months. We conclude that pre-ESWL placement of a cobra catheter into the lower pole calix and intermittent irrigation during the procedure are potentially useful adjuncts in the successful treatment of lower caliceal calculi.

Postoperative angiographic evaluation of gastroepiploic artery grafts: Technical considerations and short‐Term patency

Follow-up angiography was performed in 37 patients with right gastroepiploic artery (GEA) grafts at 27 +/- 32 days postoperatively. By the femoral approach, a 5F cobra or twist catheter was advanced selectively into the gastroduodenal artery (GDA) over a plastic-coated guidewire. In 29 patients, the GDA was successfully catheterized, and the GEA grafts were clearly visualized by the injection of 3-7 ml of contrast medium. GDA catheterization was unsuccessful in 8 patients, but in 4 of them the grafts were well visualized when 15-20 ml of contrast was injected. In the other 4 patients, visualization of the GEA grafts was poor, but the distal portions were outlined by retrograde perfusion from the native right coronary arteries. A total of 34 GEA grafts were patent (92%), and the diameters of these grafts were adequate when compared with respective recipient coronary arteries (2.8 +/- 0.9 and 2.3 +/- 0.6 mm, respectively; P less than .05). No complications were noted except for transient vasospasm (3 patients) in the GEA, hepatic artery, or both, which was relieved by the intra-arterial injection of isosorbide dinitrate (2.5 mg). Thus, the over-the-wire technique allows simple and safe GDA catheterization, which is essential for obtaining good visualization of GEA grafts.

Small coils for large hemorrhages

A 24-year-old man was stabbed in the left flank and right upper quadrant. Excretory urography revealed symmetric renal function bilaterally and a small left retropenitoneal mass. The hematocnit was 31 %. Because of the penetrating nature of the wound and relative hypotension, exploratory laparotomy was performed. At surgery, a very large left retropenitoneal hematoma extended from the splenic flexure to the pelvic inlet. Expansion of the hematoma was noted during penitoneal lavage and it was decided not to explore the retropenitoneum for fear of loss of tamponade and concomitant acute exsanguination. Postoperatively the hematocnit was 24% although blood pressure had stabilized with intraoperative crystalbid, colloid, and blood replacement. Abdominal aortography documented nightward aortic displacement and significant extravasation from a transected left third lumbar artery (fig. 1 A). Selective catheterization with a cobra catheter was followed by transcatheter Gelfoam embolization. During fluoroscopy it was obvious even the largest Gelfoam particles passed directly into the retropenitoneum due to high blood flow in the damaged vessel. A 5 French Gianturco catheter was then introduced into the third left lumbar artery and coil embolization was performed. Follow-up aortography revealed complete hemostasis (fig. 1 B). The patient made an uneventful recovery with no signs of infection, rebleed, or postembolization pain.