A new open-ended guidewire/catheter

[Fundamental Study of Inflation Pressure Resistance in an Angiographical Tube]

This study was designed to clarify the relation between the pressure resistance of an angiographical tube and the amount of contrast medium injected under a connected microcatheter used for interventional radiology (IVR). We investigated the injection pressure and the expansion rate at the center of the tube during contrast enhancement by setting the power injector to 1200 PSI pressure, with 2.0 ml/s injection speed, 10 ml injection volume, 5.0 s injection time, and 0 s rise time for tubes with different pressure resistance performance (low or high). Then we examined the amount of contrast medium material discharged from the microcatheter. The low-pressure resistant tube (less than 140 PSI) injection pressure exceeded the pressure performance. The expansion rate increased to 49%, presenting a risk of rupture. The injection pressure of the high-pressure resistant tube (less than 1200 PSI) was within the pressure-resistance performance. The expansion rate increased to 38%. However, when the contrast medium discharge amount contributing to the image was measured within the injection time under the condition of 10 ml injection for 5.0 s, the former was 2.3 ml and the latter was 4.2 ml. The entire amount was not discharged during the injection period. It became apparent that it is discharged in drips after some time. Results show that the tube expansion caused retention of the contrast medium inside, which decreases the actual amount of the injected contrast medium. From the results, we infer the possibility of preventing reduction of the injected contrast medium amount attributable to expansion.

Radiologic diagnosis and treatment of gastrointestinal hemorrhage and ischemia

Major breakthroughs in catheter, guidewire, and other angiographic equipment currently allow interventional radiologists to diagnose massive life-threatening upper and lower GI hemorrhage and to stop the bleeding safely and effectively using superselective catheterization and microcoil embolization. Similarly, the interventional radiologist can treat acute intestinal ischemia safely and effectively with selective catheterization and papaverine administration and treat chronic mesenteric ischemia by percutaneous angioplasty and stent placement. A multidisciplinary approach, including the gastroenterologist, radiologist, and surgeon, is critical in managing GI bleeding and intestinal ischemia, particularly in patients at high risk or presenting as diagnostic dilemmas.

Optimum iodine concentration of contrast material through microcatheters: hydrodynamic analysis of experimental results

It is important to increase the iodine delivery rate (I), that is the iodine concentration of the contrast material (C) x the flow rate of the contrast material (Q), through a catheter to obtain high quality arteriograms. The iodine delivery rate varies depending on the iodine concentration of the contrast material. The purpose of this study is to estimate the optimum iodine concentration (Copt) of contrast material (i.e. the iodine concentration at which I becomes maximum) through a microcatheter of a given length (L), inner diameter (D) and injection pressure (P). Iohexol, ioversol and iopamidol of 11-12 iodine concentrations (140-350, 160-350 or 160-370 mg cm(-3)) at 37 degrees C are used. I and Reynolds number (Re) of the flow of each contrast material through four microcatheters (0.49-0.68 mm in inner diameter, 1000-1500 mm in length) at injection pressures of 1.38, 2.76, 4.14 and 5.52 x 10(6) Pa (200, 400, 600 and 800 pounds per square inch) are obtained experimentally. The relationships between I and C and between I and Re are examined for each catheter and injection pressure. Copt is 160-280 mg cm(-3) for iohexol, 180-280 mg cm(-3) for ioversol and 200-300 mg cm(-3) for iopamidol. I becomes maximum when Re approximates the critical Reynolds number (Re approximately 2300). Utilizing this principle, we can estimate Copt and its flow rate through a microcatheter of a given L, D and P.

Radiology in the diagnosis and therapy of gastrointestinal bleeding

Major breakthroughs in catheter and guidewire design as well as improvements in angiographic x-ray equipment currently allow interventional radiologists to diagnose massive life-threatening upper and lower GI hemorrhage and to stop the bleeding safely and effectively using superselective catheterization and microcoil embolization. For chronic or recurrent GI bleeding, when endoscopy is unrevealing or equivocal, barium studies, CT scanning, nuclear medicine studies, and angiography can help determine the cause of bleeding. A multidisciplinary approach, including the gastroenterologist, radiologist, and surgeon, is extremely helpful in managing GI bleeding, particularly in high-risk patients or patients presenting as diagnostic dilemmas.

Magnum Meier wires with Crag Fx wire catheter for total occlusive coronary arteries

Magnum Meier wire was used with Crag Fx wire catheter instead of Magnum balloon catheter to facilitate wire crossing through total occlusion by improving flexibility of the system without losing wire pushability. Of 372 coronary angioplasty procedures performed between January 1994 and April 1995, there were 12 subacute occlusions with an interval of 3 wk or less and 30 chronic occlusions with an interval of > 3 wk. Regular over-the-wire-type balloon catheters failed to dilate four subacute occlusions and nine chronic total occlusions. Magnum Meier wire with Crag Fx wire catheter was tried for one subacute occlusion and four chronic occlusions that were undilatable with a regular balloon system and successfully dilated the subacute occlusion and three of the chronic occlusions. The lesions successfully dilated by this new approach were either long or tandem lesions in vessels that were excessively tortuous or showed an acute angle at the orifice. Thus the Magnum Meier wire with Crag Fx wire catheter can be a useful tool for dilating totally occluded lesions in tortuous coronary arteries.

The open-ended guidewire as superselective catheter for intraarterial chemotherapy: experience in 190 procedures

With intraarterial infusion, high levels of chemotherapeutic agents can be achieved in the tumoral area. We present our experience with open-ended guidewire (OEGW) associated with steerable guidewires (SGW) as superselective catheters for intraarterial chemotherapeutic infusion and embolization. This technique was used successfully in 62 patients (190 procedures) over 15 months.

Superselective embolization for renal hemorrhage with a new coaxial catheter and steerable guidewire

We utilized a new commercially available 2.2 French coaxial catheter and steerable guidewire to superselectively catheterize and embolize a small renal artery branch to abolish hemorrhage which was a complication of percutaneous nephrostomy. Because of the superselective technique and small caliber of the vessel occluded, there was no demonstrable loss of global renal function or evidence of significant cortical infarction by laboratory and radionuclide scintigraphic studies.

Superselective gelfoam embolotherapy using a highly visible small caliber catheter

A new, highly visible and flexible 3F catheter has become available for superselective catheterization and embolization. We describe the first reported series of cases in which this catheter was used for superselective Gelfoam embolization of bleeding visceral arteries.