MRI evidence that glibenclamide reduces acute lesion expansion in a rat model of spinal cord injury.

STUDY DESIGN: Experimental, controlled, animal study. OBJECTIVES: To use non-invasive magnetic resonance imaging (MRI) to corroborate invasive studies showing progressive expansion of a hemorrhagic lesion during the early hours after spinal cord trauma and to assess the effect of glibenclamide, which blocks Sur1-Trpm4 channels implicated in post-traumatic capillary fragmentation, on lesion expansion. SETTING: Baltimore. METHODS: Adult female Long-Evans rats underwent unilateral impact trauma to the spinal cord at C7, which produced ipsilateral but not contralateral primary hemorrhage. In series 1 (six control rats and six administered glibenclamide), hemorrhagic lesion expansion was characterized using MRI at 1 and 24 h after trauma. In series 2, hemorrhagic lesion size was characterized on coronal tissue sections at 15 min (eight rats) and at 24 h after trauma (eight control rats and eight administered glibenclamide). RESULTS: MRI (T2 hypodensity) showed that lesions expanded 2.3±0.33-fold (P<0.001) during the first 24 h in control rats, but only 1.2±0.07-fold (P>0.05) in glibenclamide-treated rats. Measuring the areas of hemorrhagic contusion on tissue sections at the epicenter showed that lesions expanded 2.2±0.12-fold (P<0.001) during the first 24 h in control rats, but only 1.1±0.05-fold (P>0.05) in glibenclamide-treated rats. Glibenclamide treatment was associated with significantly better neurological function (unilateral BBB scores) at 24 h in both the ipsilateral (median scores, 9 vs 0; P<0.001) and contralateral (median scores, 12 vs 2; P<0.001) hindlimbs. CONCLUSION: MRI is an accurate non-invasive imaging biomarker of lesion expansion and is a sensitive measure of the ability of glibenclamide to reduce lesion expansion.

The combination of sorafenib with transarterial chemoembolisation for hepatocellular carcinoma.

BACKGROUND: Standard of practice involves using transarterial therapy for multifocal hepatocellular carcinoma (HCC) alone and sorafenib only for more advanced HCC, but the sorafenib and transarterial therapy combination may provide greater efficacy. AIM: To evaluate the safety and efficacy of concurrent sorafenib and transarterial therapy in HCC. METHODS: Consecutive cases of HCC were treated with sorafenib and transarterial therapy, receiving sorafenib 2 to 4weeks before transarterial therapy. Baseline clinical parameters, adverse events (AEs) and survival were collected. RESULTS: A total of 47 patients received sorafenib and transarterial therapy. The majority of the patients were male (70%) with HCV (60%), median age of 60years, good performance status (0-1), stable cirrhosis (Child: A 72%; B 28%), unresectable tumour (stage: B 81%; C 19%) and median AFP of 24ng/mL. Median follow-up was 12months and median time on sorafenib was 6months. LC Bead TACE was used with a median frequency of 3. The majority of the patients (89%) experienced AEs. The most common AEs were fatigue (51%), hand-foot skin reaction (51%) and diarrhoea (43%). Grade 3 and 4 AEs included fatigue (13%) and hand-foot skin reaction (26%). Most patients required a dose reduction (66%). The main AE related to transarterial therapy was post-TACE syndrome (23%). The disease control rate was 68% at 6months. Overall median survival rate was 18.5months (95% CI 16.1-20.9months). CONCLUSION: Concurrent sorafenib and transarterial therapy is overall safe with no unexpected side effects and encouraging efficacy that warrants further study.

Is sonographic surveillance of polytetrafluoroethylene-covered transjugular intrahepatic portosystemic shunts (TIPS) necessary? A single centre experience comparing both types of stents.

AIM: To investigate whether sonographic (US) surveillance of polytetrafluoroethylene covered transjugular intrahepatic portosystemic shunts (TIPS) is necessary. MATERIALS AND METHODS: We identified 128 patients who underwent TIPS for complications of portal hypertension between January 2001 and December 2005 at a large tertiary centre. Procedural data were retrospectively analysed. US surveillance of the TIPS was performed at baseline with scheduled follow-up or whenever shunt dysfunction was suspected. Clinical and radiology reports were compared to assess US surveillance of the TIPS. RESULTS: Four hundred and twenty-six US studies were performed, with a median of three per patient (range 1-5). The median follow-up period was 378 days (range 1-1749 days). Twenty-three patients (18%) had baseline US studies performed only whereas 105 (82%) also had follow-up studies. Forty-one (32%) of 128 patients [32 (78%) Wallstent, nine (22%) Viatorr] had Doppler ultrasound abnormalities noted. Venography was performed in all 41 patients. Abnormal venography and elevated hepatic venous pressure gradient (HVPG) was seen in 34 (82.9%) of the 41 patients [29 (85.3%) Wallstent, five (14.7%) Viatorr]. Among the 34 patients, 17 (50%) [13 (76.5%) Wallstent, four (23.5%) Viatorr] had venographic abnormalities noted at the hepatic venous end accompanied by increased HVPG. All four of the Viatorr patients had minor narrowing at the hepatic venous end and HVPG measurements that ranged 3-4 mm Hg above 12 mm Hg. CONCLUSION: Considering the improved patency of covered stents in TIPS, US surveillance may be superfluous after the baseline study.

Percutaneous transpouch management of a ureteral stone and ureteral-pouch stricture in a pelvic kidney.

Stones in pelvic kidney collecting systems have not been routinely managed percutaneously in most urologic practices. Especially challenging is the management of stones in a pelvic kidney collecting system positioned posteriorly to a urinary diversion. In the present case, a 32-year-old man with a pelvic kidney and continent urinary diversion presented with fever and hydronephrosis. Drainage of the kidney was obtained percutaneously by way of an anterior approach through-and-through the urinary diversion. The patient was found to have both a ureteral stone and a ureteral-pouch anastomotic stricture on subsequent imaging. We were able to successfully treat both these problems endoscopically through a solitary percutaneous access.

Patterns of DNA sequence variation in chromosomally recognized taxa of Anopheles gambiae: evidence from rDNA and single-copy loci.

Patterns of DNA sequence variation in the ribosomal DNA (rDNA) second internal transcribed spacer (ITS2) and five unlinked single-copy nuclear loci were examined for evidence of reproductive isolation among four chromosomally recognized taxa of Anopheles gambiae from West Africa: Savanna, Bamako, Mopti and Forest, as well as sibling species An. arabiensis and An. merus. Included among the single-copy loci were three sequence-tagged random amplified polymorphic DNA (RAPD) loci, two of which (R15 and R37) had been reported as discriminating between Mopti and other chromosomal forms. Each of the five single-copy sequences were highly polymorphic in most samples. However, the R15 and R37 loci had no diagnostic value, and therefore are not recommended as tools in recognition of field-collected An. gambiae chromosomal forms. Although pairwise comparisons between species generally revealed significant levels of differentiation at all five loci, variation was not partitioned by chromosomal form within An. gambiae at any single-copy locus examined. The few exceptions to these trends appear related to a location either inside or nearby chromosomal inversions. At the tryptophan oxygenase locus inside inversion 2Rb, variation was structured only by inversion orientation and not by taxonomic designation even between An. gambiae and An. arabiensis, providing the first molecular evidence that the 2Rb inversion was transferred between species by introgressive hybridization. By contrast, the rDNA showed fixed differences between species and a difference diagnostic for Mopti, consistent with effective, if not complete, reproductive isolation. The apparent disagreement between the data from this locus and multiple single-copy loci within An. gambiae may be explained by the much lower effective population size of rDNA, owing to concerted evolution, which confers increased sensitivity at much shorter divergence times. Taken together with the accompanying reports by della Torre et al. (2001), Favia et al. (2001) and Gentile et al. (2001), our data suggest that neutral molecular markers may not have the sensitivity required to detect isolation between these recently established taxa.

Carbon dioxide digital subtraction angiography: the practical approach.

CO(2) has developed into a viable alternative to iodinated contrast for digital vascular imaging. Because CO(2) is a gas, it has a unique set of properties that affords certain advantages over iodinated contrast in a variety of settings. However, if CO(2) is used inappropriately, these same properties are associated with a unique set of rare but potentially harmful events. Therefore, it is essential that these unique characteristics be understood in order to employ a few simple precautionary measures. Fortunately, there is a delivery system currently available that is readily assembled and easy to use that ensures the appropriate administration of CO(2). This system, combined with experience, can reduce the greater labor intensity sometimes associated with CO(2) digital subtraction angiography. When it is used appropriately, CO(2) digital subtraction angiography alone or in combination with iodinated contrast offers diagnostic and interventional rewards that are not available with traditional intravascular contrast examinations.

Resolution of hypoxemia in a liver transplant recipient after ligation of a portosystemic shunt.

This report describes the unique development of pulmonary vascular dilatation and hypoxemia associated with a portosystemic shunt in a pediatric liver transplant recipient. Ligation of the shunt resulted in resolution of hypoxemia. The outcome suggests that hepatic venous return to the pulmonary circulation is important in maintaining normal pulmonary vascular caliber.

Standardized measurement of the future liver remnant prior to extended liver resection: methodology and clinical associations.

BACKGROUND: There is no agreement regarding the preoperative measurement of liver volumes and the minimal safe size of the liver remnant after extended hepatectomy. METHODS: In 20 patients with hepatobiliary malignancy and no underlying chronic liver disease, volumetric measurements of the liver remnant (segments 2 and 3 +/- 1) were obtained before extended right lobectomy (right trisegmentectomy). The ratios of future liver remnant to total liver volume were calculated by using a formula based on body surface area. In 12 patients, response to preoperative right trisectoral portal vein embolization was evaluated. In 15 patients who underwent the planned resection, preoperative volumes were correlated with biochemical and clinical outcome parameters. RESULTS: The future liver remnants increased after portal vein embolization (26% versus 36%, P < .01). Smaller size liver remnants were associated with an increase in postoperative liver function tests (P < .05) and longer lengths of hospital stay (P < .02). Preliminary data indicates an increase in major complications for liver volumes < or = 25% (P = .02). CONCLUSIONS: A simple method of measurement provides an assessment of the liver remnant before resection. It is useful in evaluating response to portal vein embolization and in predicating the outcome before extended liver resections.

Internal jugular and upper extremity central venous access in interventional radiology: is a postprocedure chest radiograph necessary?

OBJECTIVE: The necessity of obtaining a postprocedure chest radiograph after central venous access using the upper extremity or internal jugular veins and interventional radiologic techniques was evaluated. SUBJECTS AND METHODS: A prospective study of 937 consecutive central venous access procedures in interventional radiology using the internal jugular veins or upper extremities was performed from June 1995 through September 1997. Established interventional radiologic techniques were used to place various ports (n = 34) and tunneled (n = 670) and nontunneled (n = 233) catheters. All catheters were positioned using fluoroscopy and readjusted if necessary before termination of the procedure. Afterward, a chest radiograph was obtained with the patient upright to evaluate catheter position and possible procedural complications. Procedural complications and manipulations or interventions that resulted from the radiographic findings were noted. In addition, nursing time for acquisition of the chest radiograph was recorded. RESULTS: We found seven procedural complications (four air emboli, two pneumothoraces, one innominate vein laceration) significant enough to alter the patient's treatment. These complications were apparent during the examination. Postprocedure chest radiography failed to reveal any unknown complications and revealed only one catheter sufficiently malpositioned to require manipulation. The amount of nursing time to acquire postprocedure chest radiographs ranged from 8 to 40 min (mean, 23 min) per patient. CONCLUSION: When imaging guidance and interventional radiologic techniques are used for upper extremity and internal jugular central venous access, performing postprocedure chest radiography yields little benefit.

CO2 digital subtraction angiography for renal artery angioplasty in high-risk patients.

OBJECTIVE: The efficacy of CO2 digital subtraction angiography for performing renal artery angioplasty in high-risk patients was evaluated. SUBJECTS AND METHODS: From January 1997 to July 1998, 21 high-risk patients underwent 29 renal artery angioplasties using carbon dioxide as the principal contrast agent. Six patients had a known allergy to iodinated contrast material and 15 had elevated levels of creatinine. Iodinated contrast material was used only if necessary. All periprocedural allergic reactions were recorded. Before and 24 hr after the procedure, serum creatinine levels were obtained. If the creatinine level had become significantly elevated (>0.5 mg/dl), the creatinine level was acquired a second time. RESULTS: Twenty-one patients (13 men and eight women) underwent 29 angioplasties (two were bilateral and six were repeated). Four kidney transplantation patients had ostial stenosis and the remaining 17 patients had nonostial stenosis. For all patients except one angioplasty initially was a technical success, as defined by a residual stenosis of less than 30%. Supplemental iodinated contrast material was used in only six patients (average dose, 8.5 ml). A range of 80-200 ml of carbon dioxide per procedure was used (average dose, 114.6 ml). One renal artery dissection occurred, which was unrelated to the carbon dioxide. There were no allergic reactions. The level of serum creatinine remained the same after 11 procedures, decreased after 12 procedures, and increased minimally after four procedures (<0.5 mg/dl). CONCLUSION: On the basis of our preliminary findings in a small group of patients, using carbon dioxide as an intravascular contrast agent to perform renal artery angioplasty in patients who have an allergy to iodinated contrast material or who suffer from renal insufficiency is safe and efficacious.

Carbon dioxide digital subtraction angiography for renal artery stent placement.

PURPOSE: To determine the efficacy of renal artery stent placement with use of carbon dioxide as the primary contrast agent. MATERIALS AND METHODS: Seventeen hypertensive patients with renal ostial stenosis were evaluated and underwent stent placement with use of CO2 digital subtraction angiography (DSA). Besides hypertension, 11 patients had decreased renal function, three had iodinated contrast material allergy, one patient had both, and two had neither. Supplemental iodinated contrast material (25 mL or less) was used in five patients. Preprocedure and postprocedure serum creatinine levels were obtained to evaluate the effect of CO2 on renal function. Arteriography was used to evaluate stent positioning. RESULTS: Twenty-three Palmaz stents were placed in 17 patients. Six placements were bilateral, with a total of nine right and 14 left. No additional stents were required to correct malposition. One patient had a mildly significant, yet transient, rise in the postprocedure creatinine level. This patient received 10 mL of iodinated contrast material in addition to CO2. There were no allergic reactions. CONCLUSION: The utilization of CO2 DSA facilitates the accurate placement of renal artery stents by eliminating the concern for contrast material-associated nephropathy and allergy. These attributes, coupled with the benefit of low viscosity, permit unrestricted imaging, guidance, and precise positioning not afforded by iodinated contrast material.

Interventional radiology placement of twin Tesio catheters for dialysis access: review of 75 patients.

PURPOSE: To evaluate the safety and efficacy of modern interventional radiology techniques and imaging guidance for placement of jugular vein twin Tesio hemodialysis catheters. MATERIALS AND METHODS: Eighty-two sets (75 patients) of twin Tesio catheters were percutaneously placed in the right (n = 70) and left (n = 12) internal jugular veins with use of ultrasound (US) and fluoroscopic guidance. Immediate procedural and late complications were recorded. The efficacy of the Tesio system was also evaluated. RESULTS: With US and fluoroscopic guidance, the technical success for access and catheter placement was 100%. Measured dialysis blood flow rate of greater than 375 mL/min was obtained in 95% of the patients and recirculation averaged 4.6% +/- 5%. An inadvertent common carotid artery puncture occurred in one (0.6%) patient and prolonged exit site bleeding occurred in another five patients (3%). Each of these was successfully controlled with compression. More chronically, catheter thrombosis and exit site infection occurred each at the rate of 0.16 episodes per 100 catheter days. All thrombosis and exit site infections responded to local thrombolysis and antibiotic therapy, respectively. Bacteremia occurred in 20 patients and required catheter removal in five patients. There was no clinical evidence of upper extremity or superior central vein thrombosis. CONCLUSION: Placement of internal jugular, twin Tesio catheters with use of imaging and interventional techniques provides a safe and efficacious means of either short or long-term hemodialysis.

Sonographic guidance when using the right internal jugular vein for central vein access.

OBJECTIVE: The intent of this study was to substantiate the advantages of the use of sonographic guidance for central venous access via the right internal jugular vein. SUBJECTS AND METHODS: Eighty sequential patients requiring central vein access were examined with a hand-held sonography transducer to determine the size, patency, and location of the right internal jugular vein before puncture. Access to the right internal jugular vein was subsequently performed, under sterile conditions, using sonographic guidance. Periprocedural complications were prospectively recorded. Subsequently, we compared our findings with published reports of complications when visible and palpable anatomic landmarks were used for guidance during cannulation of the internal jugular vein. RESULTS: Among these 80 patients, the anatomy of the right internal jugular vein was typical in only 57 (71%). In another 13 patients (16%), sonography showed a medial position of the right internal jugular vein, anterior to the common carotid artery. In three other patients (4%), the right internal jugular vein was positioned laterally by more than 1 cm. In the remaining seven patients (9%), the vein was thrombosed. Its diameter, measured without use of the Valsalva maneuver, also varied, measuring 0.5-2.0 cm. Cannulation was achieved in all 73 patients with a patent right internal jugular vein. One puncture was required in 68 patients (93%); two punctures in three other patients (4%); and three punctures in the remaining two patients (3%). In no case was the common carotid artery inadvertently punctured. Only one periprocedural complication occurred, and it was unrelated to the use of sonographic guidance. CONCLUSION: Sonographic guidance for central vein access via the right internal jugular vein is safer and more efficient than the traditional landmark approach.

Angiography with carbon dioxide (CO2).

CO2 possesses many advantages over conventional iodinated contrast agents used for arteriography. It is nonallergic and lacks renal toxicity. Its unique properties permit use of smaller catheters in diagnostic and therapeutic angiographic procedures, allow optimal vascular imaging of various neoplasm, assist in detection of occult gastrointestinal bleeding, and facilitate TIPS procedures. With digital subtraction techniques and stacking programs, CO2 arteriography is as accurate as iodinated contrast studies in most patients and thus is the preferred arterial imaging technique in patients with contrast allergy and renal insufficiency. CO2 is also extremely inexpensive compared with available contrast agents. Understanding of the effects of buoyancy and compressibility is necessary for safe, controlled delivery of CO2 during arteriography, but only rare complications have occurred in our large experience with CO2 angiography. Thus, use of CO2 as an arterial contrast agent significantly expands the safety and utility of arterial imaging in patients with peripheral vascular disease.

Carbon dioxide (CO2) digital subtraction angiography: 26-year experience at the University of Florida.

Although the vascular system is presently being imaged by multiple high technology modalities, contrast angiography continues to be the gold standard; however, severe complications rarely occur. During the last 25 years (in over 1400 patients), CO2 has proven to be extremely safe (no allergy or renal failure). However, it is imperative to understand CO2's physical properties and potential dangers. Recently, CO2 is being routinely utilized not only because of safety, but for detection of minute amounts of bleeding, better collateral filling, and for most interventional procedures since unlimited volumes of CO2 can be injected between the catheter and guidewire. Presently, safe, reliable and "user-friendly" delivery systems are now commercially available. CO2 DSA images are now nearly comparable to iodinated contrast, and improvement in DSA images are evolving, including "stacking" software.

The arterioportal fistula syndrome: clinicopathologic features, diagnosis, and therapy.

BACKGROUND & AIMS: Arterioportal fistulas (APFs) are rare vascular disorders of the mesenteric circulation. The aim of this study was to determine the etiology, anatomical location, and main symptom at presentation of APFs, and analyze the various modes of treatment. METHODS: The etiology, clinical presentation, radiographs, and treatment of 12 patients with APFs are reported in detail, and another 76 cases published since 1980 are reviewed. RESULTS: APFs result from trauma (n = 25, 28%), iatrogenic procedures (n = 14, 16%), congenital vascular malformations (n = 13, 15%), tumor (n = 13, 15%), aneurysm (n = 12, 14%), and other causes (n = 11, 12%). The origin of APFs is the hepatic artery in the majority of patients (n = 56, 65%). The main symptoms at presentation are lower or upper gastrointestinal bleeding (n = 29, 33%), ascites (n = 23, 26%), heart failure (n = 4.5%), or diarrhea (n = 4.5%). Radiological intervention provides definitive treatment in 42% (n = 33) of patients, whereas the remainder are treated by surgery alone (n = 27, 31%) or a combination of radiological intervention and surgery (n = 8, 9%). CONCLUSIONS: APFs result in a protean syndrome variously combining portal hypertension and other hemodynamic imbalances (heart failure, intestinal ischemia). Single or multiple interventional radiological procedures using arterial and/or venous approaches allow definitive treatment of most APFs. With increasing technological advances, it is anticipated that surgery will only be indicated in rare instances after failure of radiological intervention(s).