Inline Balloon Occlusion-Assisted Delivery of Ethylene Vinyl Alcohol Copolymer for Peripheral Arterial Applications: A Multicenter Case Series

PURPOSE

To assess the feasibility, safety, and efficacy of balloon-assisted delivery of ethylene vinyl alcohol copolymer (EVOH) for a range of peripheral arterial applications.

MATERIALS AND METHODS

Six academic medical centers entered retrospective data on 46 consecutive patients (27 men, 19 women; ages, 11-94 y; mean age, 50.3 y) who underwent 60 balloon-assisted EVOH procedures. The cohort was restricted to procedures involving peripheral, nonneural arteries 1-5.5 mm in diameter. Clinical indications included a wide range of vascular pathologic conditions (most commonly arteriovenous malformations [n = 20], renal angiomyolipomas [n = 8], and acute hemorrhage [n = 9]) and targeted visceral and musculoskeletal peripheral arteries. Data collected included sex, age, clinical indication, arterial pathology, arteries embolized, type of occlusion balloon microcatheter, type and concentration of EVOH agent, effectiveness as an embolic backstop, vessels protected, adequacy of EVOH cast penetration, catheter extraction, nontarget embolization, and complications.

RESULTS

Balloon occlusion prevented EVOH reflux in 59 of 60 procedures (98.3%). Nontarget EVOH embolization occurred in 2 procedures (3.3%). Adequate EVOH cast penetration and complete filling of the target pathologic structure were seen in 57 of 60 procedures (95%). Balloon deflation and uneventful extraction occurred in all procedures; small EVOH fragments detached into target arteries in 2 cases. One major (1.7%) and 2 minor (3.3%) complications occurred.

CONCLUSIONS

Balloon-assisted EVOH embolization of peripheral arteries is feasible, safe, effective, and versatile. The primary advantage of balloon-assisted EVOH embolization is the ability to apply more injection pressure to advance the EVOH cast assertively into the pathologic structure(s).

Role of contrast-enhanced ultrasound (CEUS) in evaluation of thermal ablation zone

PURPOSE

Thermal ablation has emerged as a mainstay therapy for primary and metastatic liver malignancy. Percutaneous thermal ablation is usually performed under CT and/or ultrasound guidance. CT guidance frequently utilizes iodinated contrast for tumor targeting, with additional radiation and contrast required at the end of the procedure to ensure satisfactory ablation margins. Contrast-enhanced ultrasound (CEUS) is an imaging technique utilizing microbubble contrast agents to demonstrate blood flow and tissue perfusion. In this study, we performed a retrospective review to assess the utility of CEUS in the immediate post ablation detection of residual tumor.

METHODS

Sixty-four ablations were retrospectively reviewed. 6/64 ablations (9.4%) had residual tumor on the first follow-up imaging after thermal ablation. There were two groups of patients. Group 1 underwent standard protocol thermal ablation with CT and/or ultrasound guidance. Group 2 not only had thermal ablation with a protocol identical to group 1, but also had CEUS assessment at the conclusion of the procedure to ensure satisfactory ablation zone.

RESULTS

The residual tumor rate in group 1 was 16.7% and the residual tumor rate in group 2 was 0%. The difference between the groups was statistically significant with a p value of 0.023. The results suggest that using CEUS assessment immediately after the ablation procedure reduces the rate of residual tumor after thermal ablation.

CONCLUSION

CEUS evaluation at the end of an ablation procedure is a powerful technique providing critical information to the treating interventional radiologist, without additional nephrotoxic contrast or ionizing radiation.

Beyond hemostasis: spectrum of gynecologic and obstetric indications for transcatheter embolization

Percutaneous vascular embolization is a useful therapeutic option for a wide range of gynecologic and obstetric abnormalities. Transcatheter embolization procedures performed with the use of radiologic imaging for guidance are minimally invasive and may obviate surgery, thereby decreasing morbidity and mortality and safeguarding the patient's future fertility potential. To integrate this treatment method optimally into patient care, knowledge is needed about the clinical indications for therapeutic embolization, the relevant vascular anatomy, technical considerations of the procedure, and the potential risks and benefits of embolization. The most well-known and well-studied transcatheter embolization technique for treating a gynecologic-obstetric condition is uterine fibroid embolization. However, the clinical indications for transcatheter embolization are much broader and include many benign gynecologic conditions, such as adenomyosis and arteriovenous malformations, as well as intractable bleeding due to inoperable advanced-stage malignancies. Uterine artery embolization may be performed to prevent or treat bleeding associated with various obstetric conditions, including postpartum hemorrhage, placental implantation abnormality, and ectopic pregnancy. Embolization of the uterine artery or the internal iliac artery also may be performed to control pelvic bleeding due to coagulopathy or iatrogenic injury, and ovarian vein embolization has been shown to be effective for the management of pelvic congestion syndrome. The article discusses these and other gynecologic and obstetric indications for transcatheter embolization, provides detailed descriptions of imaging findings before and after embolization, and reviews procedural techniques and outcomes.

Thermal ablation of osteoid osteoma: overview and step-by-step guide

Osteoid osteoma is a small, benign but painful lesion with specific clinical and imaging characteristics. Computed tomography is the imaging modality of choice for visualization of the nidus and for treatment planning. Complete surgical excision of the nidus is curative, providing symptomatic relief, and is the traditionally preferred treatment. However, surgery has disadvantages, including the difficulty of locating the lesion intraoperatively, the need for prolonged hospitalization, and the possibility of postoperative complications ranging from an unsatisfactory cosmetic result to a fracture. Percutaneous radiofrequency (RF) ablation, which involves the use of thermal coagulation to induce necrosis in the lesion, is a minimally invasive alternative to surgical treatment of osteoid osteoma. With reported success rates approaching 90%, RF ablation should be considered among the primary options available for treating this condition.

Prospective evaluation of vascular complications after liver transplantation: comparison of conventional and microbubble contrast-enhanced US

PURPOSE

To prospectively compare diagnostic performance of conventional Doppler ultrasonography (US) and microbubble contrast material-enhanced US for assessment of vascular complications after liver transplantation, with clinical follow-up or angiography as reference standard.

MATERIALS AND METHODS

This study was approved by institutional review board and was HIPAA compliant. Written informed consent was obtained. Seventy-two patients (49 men, 23 women; average age, 52.3 years) were included in this study. Patients who had undergone liver transplantation underwent conventional color Doppler and contrast-enhanced US of the liver. Quality of hepatic artery (HA) and portal vein (PV) visualization, contrast material arrival time, and time for complete evaluation of vasculature were compared for both techniques. McNemar test was used to compare vascular flow visualization scores; Student t test was used to compare mean study times with both techniques. Patients without HA flow at Doppler US underwent angiography; those with flow were followed up clinically. McNemar test was used to compare sensitivity of both techniques.

RESULTS

Contrast-enhanced US helped significantly improve flow visualization in hepatic vessels (P < .001). Mean contrast material arrival time was 13.7 seconds +/- 3.8 (standard deviation) in proper HA and 20.7 seconds +/- 6.3 in PV. Mean study time decreased from 27.4 minutes +/- 13.9 to 9.3 minutes +/- 4.5 (P < .01). Doppler US failed to depict HA flow in eight patients; contrast-enhanced US showed flow in six and no flow in two of these patients. Follow-up results confirmed contrast-enhanced US findings. Sensitivity, specificity, and accuracy for Doppler US were 91.3%, 100%, and 91.5%, respectively. Sensitivity, specificity, and accuracy of contrast-enhanced US were all 100%. Sensitivity and accuracy values of the two techniques were significantly different (P < .014); there was no significant difference in specificity (P > .99)

CONCLUSION

Contrast-enhanced US helped improve flow visualization in the HA and PV, decrease scanning time, and correctly differentiate between thrombosis and a patent artery in patients without HA flow at conventional Doppler US.

N-butyl cyanoacrylate embolization for control of acute arterial hemorrhage

PURPOSE

To report the initial clinical experience with the use of n-butyl cyanoacrylate (NBCA) for embolization of acute arterial hemorrhage from varied etiologies and at varied anatomic sites.

MATERIALS AND METHODS

Sixteen patients who demonstrated active extravasation of contrast material and/or arterial abnormality underwent NBCA embolization. Sites of embolization included the gastrointestinal tract, kidney, liver, uterus, adrenal gland, extremity, and chest wall. Standard coil or particulate embolization had previously failed in 10 patients. NBCA was used as the initial embolic agent in the remaining six patients. After treatment, serial hematocrit levels, transfusion requirements, and clinical signs and symptoms were monitored for stabilization. Patients were evaluated for signs and symptoms of end-organ damage.

RESULTS

NBCA embolization was successful in 12 of 16 patients (75%), who exhibited complete cessation of bleeding. In four patients (25%), NBCA embolization was of no benefit. Embolization failed in two of 16 patients (12.5%), who showed evidence of recurrent bleeding after use of NBCA. The remaining two patients (12.5%) died within 24 hours of the procedure. None of the 16 patients developed clinical signs of end-organ damage or iatrogenic ischemia attributable to NBCA.

CONCLUSIONS

In this initial limited series, NBCA embolization was shown to be a feasible and effective method to control acute arterial hemorrhage. NBCA embolization was able to stop arterial bleeding even when previous coil or particulate embolization had failed.

Intellectual systems for differential diagnostics within groups of hardly distinguished diseases

A new method of mathematical modeling based on ideas of the artificial intelligence has been developed called as a method of a "mosaic portrait". A description of a universal computer system "Differentiated diagnostics" is given into which it is possible to introduce the "mosaic model" for any group of diseases which are difficult to distinguish. On its base a number of diagnostic medical intellectual systems have been developed.

Vena cavography with CO(2) versus with iodinated contrast material for inferior vena cava filter placement: a prospective evaluation

PURPOSE

To determine whether carbon dioxide (CO(2)) vena cavography can safely guide the placement of inferior vena cava (IVC) filters.

MATERIALS AND METHODS

One hundred nineteen patients were prospectively enrolled in this study. CO(2 )cavograms were obtained and evaluated for IVC diameter, location of renal veins, and presence of thrombus and venous anomalies. If CO(2 )cavography was judged to be adequate, an IVC filter was deployed. After filter placement, cavography was performed with iodinated contrast material; these images were compared with the CO(2) cavograms.

RESULTS

Two patients experienced mild side effects related to venous CO(2) injection. Comparison of cavograms obtained with CO(2) and iodinated contrast-enhanced material showed the caval size to be within 3 mm in all 119 patients. In 116 patients (97.5%), CO(2) cavography was judged to be adequate, and in 115 patients, filters were placed. In three (2.5%) patients, it was necessary to perform iodinated contrast-enhanced cavography before filter deployment. All six cases of venous anomaly and 11 (78.6%) of 14 cases of thrombosis were clearly identified with CO(2) cavography. One filter was maldeployed owing to misinterpretation of the CO(2) cavogram.

CONCLUSION

CO(2) cavography is well tolerated, safe, and adequate for identification of the parameters necessary for filter deployment. It is especially valuable in patients with a history of reaction to iodinated contrast material or renal insufficiency.

A novel mutation in the CAG triplet region of exon 1 of androgen receptor gene causes complete androgen insensitivity syndrome in a large kindred

Complete androgen insensitivity syndrome (CAIS) is an X-linked inherited disease caused by mutations in the androgen receptor (AR) gene. We have previously reported the largest kindred of CAIS, with 17 46,XY psychosexual and phenotypic females who lack secondary sexual hair. Analysis of AR binding indicated a receptor-negative form of complete androgen insensitivity, and DNA linkage analysis indicated that the absent binding was not caused by a large AR gene deletion. Using PCR-single-strand DNA conformational polymorphism, PCR-denaturing gradient gel electrophoresis, and DNA sequencing, we have identified a novel mutation in the polymorphic CAG trinucleotide region of exon 1 of the AR gene, where a single adenine is inserted, or equivalently, a GC-dinucleotide is deleted at this region of the gene. The mutation results in a frameshift at amino acid 60 and a premature termination of the receptor downstream of the mutation. This predicts a mutant AR with only 79 amino acids in the amino-terminal of AR protein, prohibiting binding to the ligand, as well as the cognate DNA. The rest of the encoding regions of the AR gene in the affected subjects are normal. These results are consistent with previous ligand binding and DNA linkage analysis studies. This new mutation in the CAG trinucleotide area of exon 1 of the AR gene represents the first example of a defect in a CAG repeat causing CAIS in this large kindred. All previous reported variants in this region are changes in the number of triplet repeats.

A novel mutation of the human luteinizing hormone receptor in 46XY and 46XX sisters

We report a novel homozygous mutation of the LH receptor (LHR) gene in three siblings: two 46XY and one 46XX. The 46XY siblings presented with female external genitalia, primary amenorrhea, and lack of breast development. Hormonal evaluation revealed a markedly elevated LH level with a low testosterone level, which failed to increase after human CG stimulation. Enzymatic deficiencies of testosterone biosynthesis were eliminated as possible etiologies. Histologic analysis of the inguinal gonads in a 46XY sibling revealed no Leydig cells; Sertoli cells, spermatogonia, and primary spermatocytes were seen. The 46XX sibling had female external genitalia, normal breast development, and primary amenorrhea. Hormonal analyses showed markedly elevated LH levels and low plasma 17 beta-estradiol levels. Genetic analysis of the LHR revealed a homozygous missense mutation at exon 11 of the LHR gene. Guanine was replaced by adenine (GAA-->AAA), resulting in a substitution of lysine for glutamic acid (glu) at amino acid position 354 of the receptor. This mutation is located in the extracellular domain adjacent to the first transmembrane helix of the LHR. Glutamic acid at position 354 of the LHR has been highly conserved throughout evolution. Functional analysis of the LHR mutation, using an in vitro mutagenesis-transfection assay, demonstrated complete loss of function, indicated by the lack of cAMP production after human CG stimulation in transfected human embryonic kidney 293 cells. Screening of family members demonstrated heterozygosity for the mutation, indicating autosomal recessive inheritance. Delineation of the specific genetic defect in this family confirms recent reports that a single mutation in the LHR gene causes male pseudohermaphroditism in 46XY subjects and primary amenorrhea in 46XX subjects. More importantly, it also defines a new region of the LHR molecule that is critical for biologic activity.

Natural potent androgens: lessons from human genetic models

Male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase-3 (17 beta-HSD-3) deficiency and 5 alpha-reductase-2 (5 alpha-RD-2) deficiency provides natural human genetic models to elucidate androgen actions. To date, five 17 beta-HSD isozymes have been cloned that catalyse the oxidoreduction of androstenedione and testosterone and dihydrotestosterone (DHT), oestrone and oestradiol. Mutations in the isozyme 17 beta-HSD-3 gene are responsible for male pseudohermaphroditism due to 17 beta-HSD deficiency. The type 3 isozyme preferentially catalyses the reduction of androstenedione to testosterone and is primarily expressed in the testes. Fourteen mutations in the 17 beta-HSD-3 gene have been identified from different ethnic groups. Affected males with the 17 beta-HSD-3 gene defect have normal wolffian structures but ambiguous external genitalia at birth. Many are raised as girls but virilize at the time of puberty and adopt a male gender role. Some develop gynaecomastia at puberty, which appears to be related to the testosterone/oestradiol ratio. Two 5 alpha-reductase (5 alpha-RD) isozymes, types 1 and 2, have been identified, which convert testosterone to the more potent androgen DHT. Mutations in the 5 alpha-RD-2 gene cause male pseudohermaphroditism, and 31 mutations in the 5 alpha-RD-2 gene have been reported from various ethnic groups. Such individuals also have normal wolffian structure but ambiguous external genitalia at birth and are raised as girls. Virilization occurs at puberty, often with a gender role change. The prostate remains infantile and facial hair is decreased. Balding has not been reported.

The identification of 5 alpha-reductase-2 and 17 beta-hydroxysteroid dehydrogenase-3 gene defects in male pseudohermaphrodites from a Turkish kindred

Male pseudohermaphroditism (MPH) is characterized by incomplete differentiation of male genitalia in the presence of testicular tissue. Enzymatic defects involving androgen synthesis or action are causes of MPH. We studied the molecular genetics of a large isolated inbred Turkish kindred with MPH due to either 5 alpha-reductase-2 (SRD5A2) or 17 beta-hydroxysteroid dehydrogenase-3 (17 beta HSD3) gene defects. Using single strand DNA conformational polymorphism analysis and DNA sequencing, a new mutation in exon 5 of SRD5A2 gene was detected in certain male pseudohermaphrodites from this kindred. This single base deletion (adenine) resulted in a frame shift at amino acid position 251 resulting in the addition of 23 amino acids at the carboxyl-terminal of this 254-amino acid isozyme. Transfection expression of the mutant isozyme in CV1 cells showed a complete loss of enzymatic activity in the conversion of [14C]testosterone to dihydrotestosterone, without a change in the messenger ribonucleic acid level compared to that of the wild-type isozyme. Analysis of the 17 beta HSD3 gene in other male pseudohermaphrodites from this kindred revealed a single point mutation (G-->A) at the boundary between intron 8 and exon 9, disrupting the splice acceptor site of exon 9. In this kindred, in addition to the identification of male pseudohermaphrodites with either a homozygous SRD5A2 or 17 beta HSD3 gene defect, other male pseudohermaphrodites were found to be genetically more complex: e.g. homozygous for the SRD5A2 defect and heterozygous for the 17 beta HSD3 defect, or homozygous for the 17 beta HSD3 defect and heterozygous for the SRD5A2 defect. Also, phenotypically normal carriers were identified with either one or both gene defects. Homozygous male pseudohermaphrodites with SRD5A2 or 17 beta HSD3 gene defects were phenotypically distinguishable by the presence of mild gynecomastia in the latter. Hormone data were consistent with the particular homozygous gene defect. In summary, we show 1) the novel existence of two gene defects, SRD5A2 and 17 beta HSD3, each causing MPH within a large isolated Turkish kindred; 2) that the two defects segregate independently and may be inherited from two different progenitors; and 3) analysis of a new mutation in exon 5 of SRD5A2 gene, supporting the functional importance of the carboxyl-terminal of 5 alpha-reductase-2 isozyme.

Gastrointestinal hemorrhage due to duodenal erosion by a biliary wallstent

A self-expanding metallic stent (Wallstent) was used to relieve obstruction of the common bile duct in a young male with a desmoplastic small cell tumor of the abdomen. Two months after insertion and following a course of chemotherapy the lower end of the stent eroded the mucosa of the second part of the duodenum causing severe gastrointestinal hemorrhage which necessitated laparotomy and trimming of the stent. This complication may have been due to shrinking of the tumor as well as thrombocytopenia following chemotherapy.

5 alpha-reductase-2 gene mutations in the Dominican Republic

Male pseudohermaphroditism due to 5 alpha-reductase deficiency was clinically and biochemically described in a large Dominican kindred of 23 families with 38 affected subjects in 1974. Recently, the 5 alpha-reductase-2 gene defect in the large Dominican kindred was found to be due to a single base substitution of thymidine (TGG) for cytosine (CGG) on exon 5 of the 5 alpha-reductase-2 gene, causing a tryptophan replacement of arginine at amino acid 246 (R246W) of the enzyme. In the present report, affected subjects from four additional Dominican families were studied to determine whether they carried the same 5 alpha-reductase-2 gene defect as the large kindred, suggesting a common ancestry for the gene defect within this small country. Using single strand conformational polymorphism and DNA sequencing, two other mutations of the 5 alpha-reductase-2 gene were found in affected subjects from two of the four families. A point mutation on exon 2 of the 5 alpha-reductase-2 gene, in which substitution of adenine (GAC) for guanine (GGC) caused an aspartic acid replacement of glycine at amino acid 115 (G115D), was demonstrated in one of these families, and a substitution of adenine (AGT) for guanine (GGT) on exon 3 causing a serine replacement for glycine at amino acid 183 (G183S) was detected in the other family. Affected subjects from the two remaining families demonstrated the same exon 5 mutation of the 5 alpha-reductase-2 gene as previously detected in the large Dominican kindred. The phenotypic and biochemical characteristics of the male pseudohermaphrodites were similar regardless of the genetic defect, except that one affected subject (C-VI-2) with the same exon 5 mutation as the large Dominican kindred had much more facial and body hair. Thus, the identification of multiple mutations in the 5 alpha-reductase-2 gene in male pseudohermaphrodites from the Dominican Republic demonstrates a lack of common ancestry, as had been previously postulated.

Admixture of heparin with urokinase to decrease thrombolysis time and urokinase dose in polytetrafluoroethylene dialysis graft recanalization

PURPOSE

To determine whether the addition of heparin to urokinase during dialysis graft thrombolysis can lower urokinase dose and shorten procedure time.

PATIENTS AND METHODS

Patients who underwent dialysis graft thrombolysis during an 18-month period were studied retrospectively. Twenty patients were treated with urokinase alone, and 19 patients were treated with urokinase and heparin. Thrombolysis was performed in the angiography suite by using a crossed-catheter technique. Urokinase was administered directly into the thrombus. In patients receiving heparin, 5,000 IU was added directly to the initial urokinase solution.

RESULTS

In patients who received urokinase alone, an average of 750,000 U of urokinase was used, and the average procedure time was 2 hours 42 minutes. When heparin was added, an average of 435,000 U of urokinase was used, and the average procedure time was 2 hours.

CONCLUSION

The addition of heparin to urokinase can decrease both urokinase dose and thrombolysis time in the recanalization of dialysis grafts.

HIV infection and AIDS: attitudes and knowledge of Arizona pharmacists

OBJECTIVE

To assess Arizona pharmacists' attitudes and knowledge regarding HIV infection and AIDS.

METHODS

Mailing of a 7-page survey, which included demographic and attitudinal items, as well as preparedness, comfort, and knowledge scales.

SETTING

Randomly selected pharmacists registered and residing in Arizona.

PARTICIPANTS

Of the 479 pharmacists surveyed, 41 were removed from the sample because they had moved with no forwarding address, were retired or not practicing, or had died. The response rate was 46% for the remaining 438 pharmacists. A final sample size of 199 was obtained.

RESULTS

The respondents had a high level of preparedness and comfort in addition to positive attitudes. Overall, their knowledge level was low. Inpatient pharmacists had a higher level of therapeutic knowledge (p < 0.0001) and were more willing to work with a person infected with HIV than were outpatient pharmacists (p = 0.05). Pharmacists who had attended at least 1 HIV/AIDS-related continuing education (CE) program had higher levels of preparedness (p < 0.0001), comfort (p = 0.01), and knowledge (p < 0.0001) than those who had not. The majority of respondents believed that an HIV/AIDS CE program should be mandatory.

CONCLUSIONS

Although Arizona pharmacists feel prepared, are comfortable, and have positive attitudes regarding patients with HIV/AIDS, their level of knowledge is low. The results of this study may be used by CE providers to design programs to meet the educational needs of pharmacists.

The biochemical and phenotypic characterization of females homozygous for 5 alpha-reductase-2 deficiency

The biochemical and physiologic manifestations of decreased 5 alpha-dihydrotestosterone (DHT) in females are characterized. Three females from the large Dominican kindred with 5 alpha-reductase-2 deficiency were identified as homozygous for a point mutation (R246W, C-->T) on exon 5 of the 5 alpha-reductase-2 gene by single strand DNA conformational polymorphism analysis and DNA sequence analysis. Body hair was decreased; there was no history of acne. Despite delayed menarche, all were fertile, and two had twins. Urinary 5 beta/5 alpha C19 and C21 steroid metabolite ratios were elevated. Plasma testosterone was normal to elevated, with low DHT, resulting in an increased testosterone/DHT ratio. 3 alpha,5 alpha-Androstanediol glucuronide was low. Menstrual cycle profiling performed in two subjects showed ovulatory gonadotropin peaks. Sebum production was normal. 5 alpha-Reductase-2-deficient homozygotic females demonstrate the importance of DHT in the physiology and pathophysiology of body hair growth. Normal sebum implies regulation by the 5 alpha-reductase-1 isoenzyme. Delayed puberty suggests involvement of 5 alpha-reductase-2 in menarche at the hypothalamic/pituitary and/or ovarian level. As two had nonidentical twins, DHT and/or the DHT/estradiol ratio may regulate follicular development, with lower levels permitting more than one dominant follicle per cycle and higher levels impairing follicular development and ovulation. Thus, females with 5 alpha-reductase-2 deficiency highlight a role for DHT in hirsutism and/or menstrual disorders.

Intentional occlusion of a transjugular intrahepatic portosystemic shunt

The transjugular intrahepatic portosystemic shunt (TIPS) procedure is a well-described means of treating portal hypertension and its complications. Occasionally, the consequences of this shunt prompt the desire for its subsequent obliteration. We report one unsuccessful and one successful method of TIPS occlusion.

Hemodialysis graft salvage with endoluminal stents

The most common cause of failure of hemodialysis access sites is stenosis within the site. The stenoses have traditionally been corrected surgically, but endovascular techniques may be an alternative method to treat these flow-limiting lesions and maintain graft patency. Over a recent 17-month period, endoluminal stents to relieve stenoses resistant to balloon dilatation alone were placed in 14 access sites. All sites were located on the upper extremity (13 PTFE bridge grafts and 1 A-V fistula). A total of 20 stents were placed: seven at the venous anastomosis, 12 in the venous outflow tract (including 3 in the subclavian vein), and one within the graft. Nine patients had placement of a single stent, four patients had two stents placed, and one patient had three. An additional eight stenotic lesions within these 14 sites were successfully dilated without need of a stent. After stent placement, these 14 sites have remained functional for a mean of 6.2 months. Four were functioning without further intervention at a mean of 8.5 months. Nine sites occluded at a mean of 4.7 months. The remaining site remained functional until death of the patient 10 months after stent placement. Of the nine failed sites, four developed restenosis at the site of stent placement, four developed stenoses at other sites, and the other site was abandoned. Three stents were placed in subclavian vein stenoses, and none of these has failed. Further study is necessary to determine whether endovascular stenting of dialysis access site stenoses will prove to be a durable, cost-effective alternative to surgical revision.

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.

Prevalence of infection following hepatic chemoembolization with cross-linked collagen with administration of prophylactic antibiotics

PURPOSE

The authors present their experience with 494 hepatic chemoembolization (HCE) procedures in 236 patients with administration of a mixture of cross-linked collagen and chemotherapeutic agents. The prevalence of infectious complications was compared in patients who did and did not receive prophylactic administration of antibiotics as part of the HCE procedure.

PATIENTS AND METHODS

Fourteen HCE procedures in nine patients were performed without prophylactic antibiotics (PA). These patients underwent embolization with cross-linked collagen alone or with low-dose cisplatinum. All of the remaining 480 procedures in 227 patients were performed with PA.

RESULTS

One of the nine patients (11%) who did not receive PA experienced fatal sepsis within 24 hours of HCE. Of the 227 patients who did receive antibiotics, six (2.6%) developed hepatic abscess and no fatal sepsis was encountered.

CONCLUSION

Use of PA decreases the prevalence of infectious complications following HCE.

Percutaneous retrieval of a misplaced titanium Greenfield filter

Vena caval filters are considered permanent indwelling devices. Occasionally, malposition of a filter prompts a desire for its removal. We report a method of percutaneous retrieval of a titanium Greenfield filter by snare.

Effectiveness of transcatheter embolization in the control of hepatic vascular injuries

PURPOSE

The authors describe their 11-year experience with transcatheter embolization (TCE) in the treatment of patients with hemorrhagic hepatic injuries.

PATIENTS AND METHODS

Twenty-eight TCE procedures were performed in 24 patients between 1980 and 1991. Injuries in 21 patients were due to vehicular or criminal trauma; in three patients, injuries were iatrogenic. There were 21 male and three female patients (age range, 6-64 years). All patients underwent angiography and had evidence of active hemorrhage, pseudoaneurysm, or arteriovenous fistula (AVF). All embolizations were performed with use of Gianturco coils, microcoils, or gelatin sponge.

RESULTS

TCE was technically successful in occluding hepatic vascular lesions in 21 of 24 patients (88%). Technical failures were due to the inability to select the appropriate vessel for embolization in two cases and due to a persistent AVF that did not occlude despite further attempts at embolization. Lesions recurred in two patients who underwent initially successful TCE. Both patients were treated effectively with repeated TCE. Only two catheter-related complications were encountered, both after successful TCE. Twenty-one patients survived to be discharged from the hospital. Two patients among the group treated successfully and one from the group in whom treatment failed died.

CONCLUSION

This experience demonstrates that TCE is effective in the management of hepatic vascular injuries due to trauma.

Drug therapy for geriatric depression

Depression is a common problem in elderly patients. The identification and treatment of depression may be more complex in older than in younger patients because of co-existing illnesses and concurrent drug therapy. In addition, a variety of medical conditions and drugs can cause depression. The pharmacology and pharmacokinetics of the cyclic antidepressants have been extensively studied. These agents are hepatically metabolised, often to an active agent. The clearance of the parent compound and the active metabolite(s) may be reduced in elderly patients, causing drug accumulation and increased toxicity. The cyclic antidepressants interact with a variety of neurotransmitters and their receptors. While these effects explain many of the adverse effects of the cyclic antidepressants, it is not clear whether the noradrenergic and serotoninergic effects of such drugs explain their antidepressant effects. Cyclic antidepressant therapy is associated with a variety of adverse effects, including sedation, anticholinergic effects and effects caused by alpha-adrenergic blockade. The cyclic antidepressants differ in their relative ability to cause these adverse effects. The newer cyclic antidepressants such as the selective serotonin reuptake inhibitors are relatively free of sedative and anticholinergic effects, but cause insomnia, nausea and possibly cardiac arrhythmias. All cyclic antidepressants appear to be equally effective. Therefore, the choice of a cyclic antidepressant for a specific patient must be based on several factors, including the risk of adverse effects. In elderly patients, the initial dose of cyclic antidepressants should be lower than the usual dose recommended for younger adults, and titrated slowly. All antidepressants require at least 2 to 3 weeks for their antidepressant effects to be seen. Because depression is a relapsing disease, maintenance antidepressant therapy may be indicated to reduce the risk of recurrent depression. The monoamine oxidase (MAO) inhibitors are effective antidepressants, especially in atypical depression. However, the adverse effects and risk of potentially lethal drug interactions of the older agents preclude their routine use. However, the new reversible MAO inhibitors may prove to be a well tolerated alternative in older patients. Antidepressant therapy should not be avoided simply because of a patient's age. However, the clinician must be conservative in the use of cyclic antidepressants in elderly patients and monitor closely for adverse drug reactions.

Portal venous branch targeting with a platinum-tipped wire to facilitate transjugular intrahepatic portosystemic shunt (TIPS) procedures

We describe a technique to aid in technically difficult transjugular intrahepatic portosystemic shunt (TIPS) procedures by sonographically guided transabdominal fine-needle portal vein puncture for placement of a 0.018-inch platinum-tipped target guidewire within an appropriate portal venous branch.

Bird's nest filter placement within an enlarged hemiazygos vein for prevention of pulmonary embolism

Thrombosis of the inferior vena cava (IVC) may result in considerable enlargement of paravertebral, azygos, and hemiazygos collateral veins that may in turn serve as pathways for thromboemboli to the pulmonary circulation. Herein we describe the transfemoral placement of a Bird's Nest filter within an enlarged hemiazygos vein to provide prophylaxis against pulmonary embolism in a patient with right femoral venous thrombosis who could not tolerate systemic anticoagulation. There had been earlier transjugular placement of a Greenfield filter within the suprarenal IVC.

A new curved peel-away sheath for central venous catheter placement

A new 10F peel-away sheath with a preformed curve is now available. The procedure for insertion of central venous catheters remains the same, with the new curved sheath replacing the straight version. In our experience, this modification facilitates the placement of central venous catheters and decreases the incidence of catheter tip malposition and kinking.

Microcatheter embolization of non-neurologic traumatic vascular lesions

PURPOSE

The authors report their experience over a 28-month period with embolization of 23 non-neurologic traumatic vascular lesions in 21 patients with use of a coaxial microcatheter coil delivery system.

PATIENTS AND METHODS

The injuries included pseudoaneurysms (n = 17), arteriovenous fistulas (n = 3), and sites of extravasation (n = 3) and were caused by gunshot, shotgun, and stab wounds, as well as motor vehicle accidents and iatrogenic trauma. All microcatheter embolizations except one were performed with 2.2-F Tracker-18 catheters inserted coaxially through 5.0-5.5-F guiding catheters. In one case, a coaxial 3-F Teflon catheter was used. In all cases platinum microcoils (almost all non-fibril) and/or straight platinum embolization wires (with fibrils) were used.

RESULTS

Twenty-one (91%) of 23 vascular lesions were successfully occluded with use of the microcatheter system. The two cases in which microcatheter embolization failed were successfully managed by using larger catheters and steel coils. Two patients with hepatic vascular lesions (one site of extravasation and a pseudoaneurysm) and one patient with a lower extremity arteriovenous fistula required two procedures each for successful treatment. Procedures were life-saving in at least two patients. Two lesions recurred during follow-up ranging from 3 days to 17 months. Both of these recurrences were successfully treated with transcatheter embolization, in one case with use of microcatheters.

CONCLUSION

Microcatheter embolization with platinum coils and wires is an effective means for treating traumatic vascular lesions. A coaxial microcatheter system allows for easier, more rapid coil/wire delivery to smaller, spasm-prone arteries in such cases.

Uncomplicated amebic liver abscess: prospective evaluation of percutaneous therapeutic aspiration

The performance of therapeutic aspiration in the treatment of amebic liver abscess, advocated and practiced in many centers, is controversial. Previously, this practice has been evaluated in retrospective analyses. To test the potential benefit of therapeutic aspiration, the authors undertook a prospective randomized trial in 57 patients admitted for suspected amebic liver abscess during a 15-month period. Sixteen patients were excluded from the trial. The remaining 41 patients were randomly included in one of two study groups to receive amebicidal therapy alone or amebicidal therapy coupled with image-guided percutaneous therapeutic aspiration. All patients in the trial recovered. No statistically significant benefit was demonstrated in the aspiration group for the two objective parameters evaluated: length of hospitalization and duration of time to becoming afebrile. Subjective improvement in symptoms after aspiration was greater in the aspiration group at a marginally statistically significant level. These data do not support the adjunctive performance of percutaneous therapeutic aspiration in the treatment of uncomplicated amebic liver abscess. Amebicidals alone were equally efficacious in treating the group studied.

Danazol increases the anticoagulant effect of warfarin

OBJECTIVE

To report two cases demonstrating an interaction between danazol and warfarin, resulting in the potentiation of warfarin's effect and bleeding complications.

DATA SOURCES

Case reports, review articles, and studies identified by MEDLINE.

STUDY SELECTION

All published English-language reports involving danazol and warfarin interactions were reviewed.

DATA SYNTHESIS

Danazol, a synthetic testosterone derivative, is used in the treatment of endometriosis, fibrocystic breast disease, menorrhagia protein C deficiency, and hemophilia. We describe two cases including an interaction between danazol and warfarin, resulting in bleeding complications. There are at least two other reported cases of this interaction. This interaction may be attributable to several mechanisms. Danazol may inhibit the metabolism of warfarin and/or it may have a direct effect on the coagulation and fibrinolytic systems.

CONCLUSIONS

Based on this report and other published cases, clinicians must be aware that danazol may increase the anticoagulant effect of warfarin. Patients receiving warfarin who are prescribed danazol must be monitored closely to prevent excessive anticoagulation and subsequent bleeding. Studies are needed to determine the frequency of this interaction and its underlying mechanisms.

Effects of passive smoking on theophylline clearance

Theophylline disposition was examined in seven passive smokers, defined as nonsmokers with long-term exposure to cigarette smoke, and seven age-matched nonsmokers with minimal smoke exposure. Subjects were given an intravenous infusion of aminophylline (6 mg/kg) and blood samples were drawn before and during the 48-hour postinfusion period. Clearance for passive smokers was 6.01 x 10(-2) L/hr.kg and for nonsmokers, clearance was 4.09 x 10(-2) L/hr.kg (p less than 0.025). Terminal elimination half-life for passive smokers was 6.93 hours versus 8.69 hours for nonsmokers (p less than 0.05). The mean residence time for passive smokers was 9.89 hours. For nonsmokers, the mean residence time was 13.11 hours (p less than 0.05). These measurements were statistically different, whereas there was no difference in volume of distribution between the groups, suggesting that passive smokers metabolize theophylline more rapidly than nonsmokers. Plasma and urine cotinine and nicotine concentrations were measured in all subjects. There was a significant difference between the subject groups in plasma (p less than 0.004) and urine (p less than 0.002) cotinine concentrations. Theophylline clearance correlated with both plasma (r = 0.73, p less than 0.01) and urine (r = 0.79, p less than 0.01) cotinine concentrations. Additional studies should be conducted to further define the pharmacokinetic characteristics of passive smokers and to assess the effects of passive smoking on drugs metabolized by the mixed function oxidase system.

Octreotide, a new somatostatin analogue

The chemistry, pharmacology, pharmacokinetics, clinical uses, adverse effects and drug interactions, dosage, availability and cost, and indications for use of octreotide, a new synthetic analogue of the peptide hormone somatostatin (SS), are reviewed. Like SS, octreotide suppresses secretion of pituitary growth hormone (GH) and thyrotropin and decreases release of a variety of pancreatic islet cell hormones including insulin, glucagon, and vasoactive intestinal peptide (VIP). Octreotide also reduces splanchnic blood flow, gastric acid secretion, GI motility, and pancreatic exocrine function and alters the absorption of water, electrolytes, and nutrients from the GI tract. The elimination half-life of i.v. octreotide is 72-98 minutes, compared with 2-3 minutes for i.v. SS. Usual administration of octreotide is by the i.v. or s.c. route. Octreotide has been studied in the treatment of hormone-secreting pituitary tumors and pancreatic islet cell tumors. Octreotide therapy lowers GH secretion and improves clinical symptoms in patients with acromegaly and may suppress clinical symptoms to a greater degree than bromocriptine. Patients with carcinoid syndrome and VIP-secreting tumors (vipomas) have had substantial improvement in clinical symptoms with administration of octreotide. This agent does not appear to be effective in the treatment of nonvariceal upper GI bleeding and acute pancreatitis; its relative usefulness in the treatment of variceal bleeding is not established. Adverse effects associated with octreotide therapy generally have been mild, including pain or burning at the injection site, abdominal pain, and diarrhea. Octreotide has been shown to interfere with absorption of oral cyclosporine. Standard initial therapy is octreotide acetate 50-100 micrograms s.c. every 8-12 hours, with titration based on clinical and biochemical effects. Up to 3000 micrograms/day of octreotide acetate has been administered to patients with acromegaly without serious adverse effect. Octreotide is marketed under the brand name Sandostatin and is available in 1-mL ampuls containing 50, 100, and 500 micrograms of octreotide acetate. Because the conditions for which octreotide appears to be most effective are uncommon, the drug should be considered for addition to the formulary in tertiary-care institutions only; addition of octreotide to the formulary of a community hospital is probably unnecessary. The synthetic analogue octreotide is longer acting and more specific in pharmacologic action than SS.(ABSTRACT TRUNCATED AT 400 WORDS)

Treatment of severe cryptosporidium-related diarrhea with octreotide in a patient with AIDS

Cryptosporidiosis commonly causes severe diarrhea in immunosuppressed patients. There currently are no antiparasitic drugs consistently effective for this infection. This case describes a 26-year-old hemophiliac patient with acquired immunodeficiency syndrome and cryptosporidiosis whose diarrhea improved with continuous intravenous administration of a long-acting somatostatin analog, octreotide. Somatostatin has a variety of inhibitory effects on gastrointestinal hormones as well as a possible nonspecific effect on gastrointestinal mucosal fluid and electrolyte secretion. The somatostatin analog should be considered for patients with secretory diarrhea refractory to other forms of therapy.

Acute interstitial nephritis associated with intermittent rifampin use

Rifampin is a widely used antimicrobial agent, most commonly administered in the treatment of tuberculosis. Since its introduction in the late 1960s, rifampin has become a standard agent in the treatment of tuberculosis, especially with the acceptance of short-course chemotherapy in the U.S. Rifampin also is being used with increasing frequency in the treatment of nontuberculous infections, especially serious staphylococcal infections. While rifampin usually is well tolerated in most patients, adverse effects, including serious forms of toxicity, have been reported. Some of these adverse effects include liver toxicity and various immunologic reactions such as skin rashes, eosinophilia, and interstitial nephritis. This report documents a case of acute interstitial nephritis, most likely secondary to intermittent rifampin administration.

Baclofen overdose with cardiac conduction abnormalities: case report and review of the literature

Cardiac conduction abnormalities and hypertension developed in a patient who ingested approximately 500 mg of baclofen (Lioresal). The patient also exhibited the more common features of baclofen overdose including coma, respiratory depression, hypotonia, and hyporeflexia. A review of the literature and a discussion of the interesting manifestations and treatment of baclofen overdose are included.

Inconsistency and institutional review boards

To assess the adequacy of peer review for research on human subjects, identical research protocols in oncology and anesthesiology were submitted to 32 institutional review boards (IRBs) at major universities with medical colleges. Each of the protocols posed serious ethical issues, contained flaws in scientific design, and provided an incomplete consent form. Twenty-two IRBs participated in the investigation, which revealed (1) consistency in the nonapproval of the three protocols, (2) substantial inconsistency among IRBs in the reasons offered in support of similar decisions, and (3) substantial inconsistency in the application of ethical, methodological, and informed-consent standards for individual review boards. This evidence suggests that revision of the protocols to satisfy particular objections would result in approval of flawed investigations.