Biomedical subjects
Publications and source records attributed to K Amplatz.
Ivalon particles were used for hepatic arterial embolization of diffuse arteriovenous malformation in a patient with hereditary hemorrhagic telangiectasia. The methods of the procedure and possible complications are discussed.
The new Amplatz retrievable filter was placed 15 times into the inferior vena cava (IVC) of 7 dogs. Retrieval of the filter was attempted in 11 cases after 1 week and in 3 cases after 2 weeks. The retrieval was successful and without complication in all 14 cases. The 15th placement resulted in thrombotic occlusion of the IVC, and no retrieval was attempted.
An inferior vena cava filter was misplaced into the pericaval retroperitoneum. This was probably secondary to placement into and avulsion of the right spermatic vein. The filter delivery system was modified, and such misplacement should now be impossible.
The advent of the in situ saphenous vein bypass procedure for peripheral lower extremity ischemic disease has placed new demands on the angiographer. It is imperative that the small runoff arteries of the calf be seen beyond the level of the ankle to include evaluation of the patency of the plantar arch. Balloon occlusion femoral angiography (BOFA) has been used in 45 consecutive lower extremities in 40 patients referred for proposed in situ saphenous vein bypass; excellent visualization of the plantar arch on the first run was obtained in 40 of 45 extremities (88.9%). The patients included 35 (87.5%) insulin-dependent diabetics with severe proximal arterial disease. Initially, in situ candidates were studied using conventional "runoff" methods; it was rarely possible to visualize the upper trifurcation vessels let alone the plantar arch by this conventional method. The BOFA method was used to provide excellent visualization of the plantar arch and foot arteries. It permits use of smaller contrast medium volumes, provides all the arteriographic anatomy on one 51 inch long film, and is safe.
Three patients with lower urinary tract fistulas after multiple operations and radiation therapy for pelvic cancer were treated with percutaneous ureteral fulguration and nephrostomy tube drainage. This technique occluded the ureter and allowed for maintenance of a dry fistula site in all 3 patients. There were no complications. The longest followup in these patients was 21 months. The procedure is simple technically and it can be performed with the patient under local anesthesia. The technique of percutaneous ureteral fulguration is described and other techniques for nonoperative occlusion of the ureter are discussed.
Benign prostatic hypertrophy (BPH) produces symptoms that currently can only be treated surgically either by open or endoscopic prostatectomy. We have undertaken animal (1) and human studies to determine if invasive radiologic techniques utilizing balloon catheters could be applied to the treatment of this common ailment. We report a series of twelve patients treated by retrograde transurethral balloon catheter prostatic dilatation. The procedure is performed using topical anesthesia with a specially designed balloon catheter (Medi-Tech, Inc.). The procedure is done on an outpatient basis and is completed within approximately 15 minutes. Relatively long-term results have resulted in persistent relief of symptoms. No complications have been encountered. We anticipate that balloon dilatation of the prostatic urethra will have a major impact on the treatment of BPH based on the promising preliminary results. Transurethral resection of the prostate (TURP) is associated with moderate morbidity and significant cost which can be reduced by the proposed procedure.
The records of 37 patients who had undergone splenoportography, including one group of 12 who were studied before 1976 and a second group of 25 who were studied after 1977, were reviewed. The primary difference was that in the second group, the tract in the spleen was occluded with absorbable gelatin sponge (Gelfoam) plugs as the needle was withdrawn. In addition, there were minor changes in technique, such as changes in the needle puncture angle and entry site. When the new technique was used, there was a significant decrease in the complications traditionally associated with splenoportography. This procedure is safe and deserves to be considered the procedure of choice in patients in whom precise anatomic information is needed preoperatively that cannot be obtained with noninvasive procedures such as ultrasound or magnetic resonance imaging.
A major drawback of currently used exchange guide wires is insufficient stiffness, causing them to buckle or dislodge when used during catheter exchanges. A new heavy-duty exchange guide wire is described that facilitates catheter exchanges around sharp corners, such as those encountered during various cardiac interventional procedures. The wire was successfully used in experimental valvuloplasty and experimental dilation of the ductus arteriosus.
Three commercial vessel dilators and a dilator of an improved design were tested during percutaneous catheterization in 16 mongrel dogs to evaluate arterial damage produced with their use. The results indicate that, although all dilators often produce arterial damage, the improved design produced much less damage. In addition, lesions were less severe overall. The dilator has been safely and successfully used in patients for percutaneous vessel catheterization for the past 30 years at the authors' institution.
Retrograde transurethral balloon dilation of the prostatic urethra was performed in five human volunteers with benign prostatic hypertrophy. Each patient underwent cystoscopy, uroflow studies, voiding cystourethrography, retrograde urethrography, and magnetic resonance imaging before dilation and at defined intervals afterward. The longest follow-up to date is 8 months. Patients were given topical anesthetics and mild sedatives, and dilation was performed with a 25-mm urethroplasty balloon catheter inflated at 3-6 atm for 10 minutes. All catheter manipulations were done with a guide wire and under fluoroscopic control. Significant resolution of symptoms of prostatism was seen in four patients. The unsatisfactory results in the last patient were believed to be caused by ineffectual dilation of predominantly middle lobe hypertrophy--a condition that is now regarded as a contraindication to dilation. This technique has promise to replace transurethral resection of the prostate as the treatment of choice for this common male ailment.
Percutaneous techniques to manage urinary fistulas have had limited success. To overcome this, self-closing metallic clips were developed to occlude the ureter. The clips are applied through a percutaneously placed 30-F Teflon sheath. A case is reported in which the clips and new technique were successfully used.
An introducer-sheath dilator is described, which was modified to protect the leading lip of the sheath during insertion, thus reducing arterial damage. The new sheath and a standard sheath were inserted into the femoral arteries of six dogs. Subsequent histologic examination of the arteries proved the new sheath to be both safe and effective.
To investigate the acute and long-term effects on the vasa vasorum after massive overdilation, canine aortic segments were dilated with Gruentzig balloon catheters to more than 100% over normal size. In the acute study, the significant lumen increase was the result of intimal and medial rupture with stretching and thinning of the adventitia. In these areas, the vasa vasorum were stretched and severed, causing adventitial hemorrhage. In the chronic study, areas of previous subtotal wall rupture with adventitial thinning were repaired by scar tissue. This repair included formation of a neomedia, hyperplasia of the adventitia, and proliferation of the vasa vasorum. No progression of luminal dilatation was seen. This study showed that in subtotal aortic wall rupture, even a severely damaged adventitia is capable of preserving the lumen from further dilatation and rupture until healing. Blood flow to the damaged vessel wall was reestablished by revascularization via capillary budding in the aortic wall.
A new guide wire that provides markedly improved torque control is described. It was compared with a conventional guide wire in two models, one simulating a drainage tube with numerous side holes and one, the biliary tree. The new wire was much more easily controlled than the conventional guide wire and passed through both models significantly faster (P less than .01 and P less than .005). Although some deterioration in control was noted when it was inserted through a catheter in vivo, the new torque-control wire still exhibited a definite improvement over conventional wires in directional control.
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The radiologic evaluation for liver transplantation involves physiologic studies of function and anatomic studies of the intrahepatic and extrahepatic structures. CT and US are successful for examining and measuring the PV and IVC in 75 per cent of cases, whereas the remaining patients will require more invasive angiographic or venographic studies. These studies require careful planning and sequencing and should be performed in the order of least invasive first, with progression to more invasive studies if necessary.
Since the first liver transplant in 1968 at the University of Minnesota, over 125 liver transplants have been performed. Postoperatively, these patients require intensive care, and many ultimately require angiographic or interventional radiologic procedures, or both, to diagnose postoperative vascular anastomotic problems, thrombotic complications, biliary anastomotic problems, and infrequently, hemorrhagic problems.