Utility of nonselective abdominal aortography in demonstrating ovarian artery collaterals in patients undergoing uterine artery embolization for fibroids.

PURPOSE: To review the incidence of ovarian collateral supply to uterine fibroids as demonstrated by nonselective abdominal aortography before uterine artery embolization (UAE) and to evaluate the effect of such visualization on interventional management. MATERIALS AND METHODS: The aortograms of 51 consecutive patients (mean age, 42.4 y; range, 30--53 y) undergoing UAE for symptomatic uterine fibroids were reviewed retrospectively for the visualization of ovarian arteries extending into the pelvis. If ovarian arteries were visualized, their size relative to the ipsilateral external iliac artery was measured. Arteries believed large enough to represent a significant blood supply to the uterine fibroids were further evaluated after UAE to determine whether flow persisted. RESULTS: In 13 of 51 patients (25%), a total of 18 ovarian arteries were identified. They were bilateral in five patients and unilateral in eight. Their sizes relative to the ipsilateral external iliac artery ranged from 8% to 57% (mean, 26%). Eight ovarian arteries with a relative size > or = 25% were further evaluated. Five of the eight (62.5%) were not visible after UAE. Of the three persistent ovarian collateral arteries, two were successfully embolized. The patient with the untreated collateral artery experienced persistent menorrhagia. CONCLUSION: Preembolization aortography with the catheter tip at level of the renal arteries demonstrated ovarian collateral arteries in 25% of patients with uterine fibroids. However, their detection influenced treatment in only 6% of the reported cases.

Effects of intraarterial thrombin in the swine model.

PURPOSE: To evaluate the effects of catheter-directed thrombin in the peripheral arterial circulation of swine. MATERIALS AND METHODS: Thrombin was injected into a single femoral artery in 20 domestic swine. Each of five animals from four dose groups received 50, 150, 250, or 1,000 U as a single dose. Bilateral femoral arterial flow was monitored for as long as 4 hours and evaluated relative to baseline and contralateral limb flow. Interval arteriographic results were evaluated by segmental patency and a numeric angiographic score. RESULTS: Mean baseline flow was 136 mL/min +/- 44, with an internal arterial diameter of 3.4 mm +/- 0.5. A transient increase in blood flow after thrombin administration was followed by diminished flow and thrombosis. These findings varied directly with dose and inversely with baseline flow. Angiographic and flow abnormalities generally improved with time and recovery was generally better in swine that received 50 or 1,000 U than in other groups. However, one animal that received 1,000 U (13.2 U/mL/min) developed stable, complete limb thrombosis. The degree of recovery varied with thrombin dose and thrombus location. At doses greater than 50 U (0.33 U/mL/min +/- 0.05), abnormalities were commonly persistent. Animals receiving the 150-U dose (1.33 U/mL/min +/- 0.41) had a higher incidence of persistent distal occlusion. Distal occlusions were less likely to resolve than proximal occlusions. CONCLUSIONS: The effect of intraarterial thrombin is directly related to dose and inversely related to baseline blood flow. In swine, a threshold for significant flow disruption and thrombosis exists above a dose of 50 U (0.33 U/mL/min +/- 0.05). A threshold dose for irreversible occlusion may also exist. Although small amounts of thrombin in a high-flow vessel may not cause significant complication, administration into the arterial circulation should be avoided.

Uterine arterial embolization: factors influencing patient radiation exposure.

PURPOSE: To investigate patient radiation exposures during uterine arterial embolization and the factors responsible for those exposures. MATERIALS AND METHODS: Clinical and procedural factors were evaluated for 42 consecutive procedures performed in 39 patients by one operator. Seven patients were excluded because of early termination (n = 1) or unusual conditions that necessitated extended procedures (n = 6). Fluoroscopic time, number of images acquired, height, and weight were available in the 35 remaining patients, and dose-area product (DAP) was available in 20. Equipment factors were evaluated by using a Lucite phantom in four angiography units from three manufacturers. RESULTS: The mean fluoroscopic time per case decreased from 30.6 to 14.2 minutes between the 1st and 5th quintiles. Mean DAP decreased from 211.4 to 30.6 Gy. cm(2) with dose reduction techniques; this primarily reflected a decreased number of acquired images. Phantom studies demonstrated many significant dose variations with magnification and equipment position. Low-dose and pulsed fluoroscopic modes reduced exposure rates in units so equipped, but roadmapping caused a silent switch to continuous fluoroscopy in two such units, which doubled the exposure rate. CONCLUSION: With operator experience and careful technique, uterine arterial embolization can be performed at radiation exposures comparable to those used in routine diagnostic studies. However, operators must be familiar with the technical parameters of their angiographic equipment.

How much guidewire is too much? Direct measurement of the distance from subclavian and internal jugular vein access sites to the superior vena cava-atrial junction during central venous catheter placement.

OBJECTIVE: The introduction of excessive lengths of guidewire during placement of central venous catheters from the internal jugular vein (IJV) or the subclavian vein (SCV) can result in rare but significant complications. To identify a "safe" guidewire insertion length, the authors performed direct intravascular measurement of the distance from these venous access sites to the superior vena cava-atrial junction (CAJ), and evaluated these distances relative to the patients' height, weight, sex, and chest radiographs. DESIGN: Prospective, nonrandomized observation. SETTING: The Interventional Radiology Department of a tertiary care referral hospital. PATIENTS: 100 adults (45 women, 55 men) evaluated during fluoroscopically directed central venous catheter placement. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The distance from the IJV or SCV access site was directly measured using fluoroscopy and an intravascular guidewire. 40 right IJVs, 31 right SCVs, 16 left SCVs, and 13 left IJVs were studied. Comparative measurements from the postprocedure radiograph were made in 20 of these cases. All measurements were correlated with patient sex, height, and weight. The mean distance from all access sites to the superior vena cava-atrial junction was 18.0 cm. The right IJV distance was the shortest, averaging 16 cm. The left SCV distance was the longest, averaging 21.2 cm. Right SCV and left IJV distances were 18.4 and 19.1 cm, respectively, but this difference was not statistically significant. Weight and radiographic measurements did not correlate with the measured vascular distance, although there was a trend toward longer distances in taller patients and males. CONCLUSIONS: Patient height, weight, and measurements from previous chest radiographs are less reliable in predicting a safe wire length than is the access site selected. In most cases, 18 cm should be considered the upper limit of guidewire introduced during central catheter placement in adults. The guidewires supplied in catheter kits should have lengths correlated to those of the catheters, and should have distance markings printed upon them.

Stent-grafts for de novo TIPS: technique and early results.

PURPOSE: To evaluate the potential benefits of placing a polytetrafluoroethylene (PTFE)-covered stent-graft during initial creation of a transjugular intrahepatic portosystemic shunt (TIPS) in clinical practice. MATERIALS AND METHODS: De novo TIPS were created with a PTFE stent-graft in four male and four female patients with symptomatic portal hypertension awaiting liver transplant. Their ages ranged from 35 to 62 (mean, 47) years. Patients were followed with TIPS ultrasound (US) and/or venography until liver transplantation or death; one remains under active study. Six recovered specimens underwent gross and microscopic evaluation. RESULTS: All TIPS placements were successful. Six shunts were primarily patent, with a mean patency of 289 days, through completion of the study. Five were found to be patent at transplant and one was found to be patent at autopsy. Explant evaluation revealed a smooth, thin layer of neointima and exclusion of biliary secretions. Three patients developed a total of four stenoses (one tandem lesion) during follow-up, leading to revision in two patients. Mean primary and total patency in these patients was achieved after 279 and 463 days, respectively. A previously occult moderate stenosis was detected after explant in another patient. Only one (nonsignificant) stenosis clearly developed in an area covered by PTFE. CONCLUSION: Placement of a de novo PTFE stent-graft during TIPS creation is feasible and may extend primary shunt patency. Appropriate positioning of the stent-graft is critical.

Placement of a flexible endovascular stent across the femoral joint: an in vivo study in the swine model.

PURPOSE: To investigate the effects of joint motion on the structural integrity of periarticular stents and on the development of neointimal hyperplasia within these devices. MATERIALS AND METHODS: In four juvenile farm swine, Wall-stents were implanted in the common femoral arteries and contralateral common femoral veins, centered at the point of maximal conformational change during passive hip flexion. Control stents were placed in the aortae and iliac veins. Angiography and transcatheter blood pressure measurements were obtained across each stent, with periarticular stents studied in flexion and extension. Two animals underwent repeated evaluation after 1 month, the others after 3 months. Findings were correlated with gross and histopathologic findings in the harvested stents. RESULTS: No stent fractures occurred. One femoral vein was injured during stent placement and was occluded 1 month later at follow-up. Hemodynamically significant stenoses were identified in one arterial stent and one venous stent at 3 months. The amount of neointimal hyperplasia was greater in periarticular stents than in controls and greater in animals studied at 1 month than in those studied at 3 months. The pattern of neointimal hyperplasia within mobile arteries was circumferentially asymmetric and thicker at the distal ends of the stents. Venous neointimal hyperplasia was thicker and markedly different in character than that seen in arterial stents from the same animals. CONCLUSIONS: Periarticular Wallstents and the underlying vascular anatomy remained structurally intact despite the stresses of repetitive motion during a 3-month period. Stents deployed across joints or in venous locations may be at greater risk for neointimal hyperplasia development and eventual occlusion than those deployed in immobile vessels and arteries. Neointimal hyperplasia may decrease in thickness after an initial period of exuberant development. Additional studies are necessary to determine long-term outcomes.

Entrapment of J-tip guidewires by Venatech and stainless-steel Greenfield vena cava filters during central venous catheter placement: percutaneous management in four patients.

We present four patients in whom bedside placement of a central venous catheter was complicated by entrapment of a J-tip guidewire by a previously placed vena cava (VC) filter. Two Venatech filters were fragmented and displaced into the superior VC or brachiocephalic vein during attempted withdrawal of the entrapped wire. Two stainless-steel Greenfield filters remained in place and intact. Fluoroscopically guided extraction of both wires entrapped by Greenfield filters was successfully performed in the angiography suite.

Single-specimen bile cytology: a prospective study of 80 patients with obstructive jaundice.

PURPOSE: To determine the sensitivity, specificity, and charges associated with single-specimen bile cytologic study in patients with obstructive jaundice. MATERIALS AND METHODS: Eighty consecutive patients with presumed malignant biliary strictures underwent percutaneous biliary drainage (PBD). Cytologic evaluation was performed on a single bile specimen from each patient collected at the time of the PBD. Final diagnoses were obtained from either percutaneous (n = 14) or surgical (n = 66) histologic specimens (gold standard). Both data sets were then compared to determine the sensitivity and specificity of bile cytology. The charges associated with bile cytodiagnosis were compared to those for other biopsy procedures utilized in the same setting. RESULTS: Eighty bile specimens were obtained with a mean of 14 mL (range, 3-65 mL) per patient with 79 (99%) specimens adequate for cytologic processing. Eleven (13%) specimens were acellular. The overall sensitivity was 15% and specificity was 100%; these values were not dependent on the volume of the bile specimen (P > .10) or type of malignancy (P = .10). For bile cytodiagnosis, the mean charge was $160 and the successful biopsy rate (true-positive plus true-negative results/total number procedures) was 27%. CONCLUSION: Single-specimen bile cytology has a low sensitivity; however, because of its convenience, simplicity, atraumatic nature, and low relative charge versus comparable procedures, it may be useful as an adjunct to PBD in patients with suspected malignant biliary disease.

Cerebellar herniation and infarction as a complication of an occult postoperative lumbar dural defect.

A patient who underwent lumbar spine surgery sustained an occult dural injury. After unrecognized suction drainage of cerebrospinal fluid through a surgical drain, caudal herniation of the cerebellum with superior cerebellar infarction developed. This mechanism should be considered in patients in whom acute mental status changes develop after spinal surgery.

Strut interlocking of titanium Greenfield vena cava filters and its effect on clot capturing: an in vitro study.

PURPOSE: To determine the influence of filter leg-interlocking on filtering efficiency of titanium Greenfield inferior vena cava filters in an in vitro model. METHODS: Titanium Greenfield filters (TGF) were placed in an inferior vena cava (IVC) flow phantom with no interlocking legs, or with one or two pairs of legs interlocked. Clot emboli of varying sizes were introduced into the stream of flow, and the frequency of successful captures by the deformed filters was recorded. RESULTS: Interlocking filter legs diminished the filtering efficiency of the TGF by up to 80% with the flow phantom in a horizontal position; no such compromise existed when the phantom was in a vertical position. CONCLUSION: When leg interlocking is verified radiographically, the filtering efficiency of the TGF is reduced, and placement of a second IVC filter may be indicated.

Behavioral and endocrine interactions between thyrotropin-releasing hormone and ethanol in normal human subjects.

Thyrotropin-releasing hormone (TRH) has been shown to antagonize the depressant effects of ethanol in animals, but conflicting findings have been reported in humans. To test whether TRH counteracts any of a variety of ethanol-sensitive behavioral measures in normal human subjects and for an effect of ethanol on TRH-induced thyrotropin (TSH) and prolactin (PRL) response, we administered TRH (500 micrograms) or placebo over 1 min intravenously, 30 min after subjects had ingested 0.8 g/kg of ethanol or a placebo drink. Blood samples for TSH and PRL were drawn prior to and 15 and 30 min after injection. Eight male subjects were studied in a balanced, crossover design with each subject receiving placebo-placebo, TRH-placebo, placebo-ethanol, and TRH-ethanol. Whereas ethanol had significant and expected effects on subjective measures, memory, disinhibition, reaction time and time perception, TRH failed to counteract any ethanol effect, except for a small effect in one memory task. Similarly, no effect of ethanol on TRH-induced TSH or PRL response was found. Though the behavioral findings could be interpreted to indicate that TRH does not alter ethanol sensitive behaviors in humans it will be necessary to utilize higher dosages of TRH and/or TRH analogues before firmly drawing this conclusion.