Percutaneous rendezvous technique for the management of a bile duct injury

The rendezvous technique typically involves combined efforts of interventional radiology, endoscopy, and surgery. It can be done solely percutaneously, whereby the interventionalist gains desired access to one point in the body by approaching it from two different access sites. We present the case of a woman who underwent cholecystectomy complicated by a bile duct injury. A percutaneous rendezvous procedure enabled placement of an internal-external drain from the intrahepatic ducts through the biloma and distal common bile duct and into the duodenum. Thus, a percutaneous rendezvous technique is feasible for managing a bile duct injury when endoscopic retrograde cholangio-pancreatography or percutaneous transhepatic cholangiogram alone has been unsuccessful.

Dodecafluoropentane Emulsion Extends Window for tPA Therapy in a Rabbit Stroke Model

Dodecafluoropentane emulsion (DDFPe) nanodroplets are exceptional oxygen transporters and can protect ischemic brain in stroke models 24 h without reperfusion. Current stroke therapy usually fails to reach patients because of delays following stroke onset. We tested using DDFPe to extend the time window for tissue plasminogen activator (tPA). Longer treatment windows will allow more patients more complete stroke recovery. We test DDFPe to safely extend the time window for tPA thrombolysis to 9 h after stroke. With IACUC approval, randomized New Zealand white rabbits (3.4-4.7 kg, n = 30) received angiography and 4-mm blood clot in the internal carotid artery for flow-directed middle cerebral artery occlusion. Seven failed and were discarded. Groups were IV tPA (n = 11), DDFPe + tPA (n = 7), and no therapy controls (n = 5). DDFPe (0.3 ml/kg, 2 % emulsion) IV dosing began at 1 h and continued at 90 min intervals for 6 doses in one test group; the other received saline injections. Both got standard IV tPA (0.9 mg/kg) therapy starting 9 h post stroke. At 24 h, neurological assessment scores (NAS, 0-18) were determined. Following brain removal percent stroke volume (%SV) was measured. Outcomes were compared with Kruskal-Wallis analysis. For NAS, DDFPe + tPA was improved overall, p = 0.0015, and vs. tPA alone, p = 0.0052. For %SV, DDFPe + tPA was improved overall, p = 0.0003 and vs. tPA alone, p = 0.0018. NAS controls and tPA alone were not different but %SV was, p = 0.0078. With delayed reperfusion, DDFPe + tPA was more effective than tPA alone in preserving functioning brain after stroke. DDFPe significantly extends the time window for tPA therapy.

Dodecafluoropentane Emulsion (DDFPe) Decreases Stroke Size and Improves Neurological Scores in a Permanent Occlusion Rat Stroke Model

Background:

Dodecafluoropentane emulsion (DDFPe), given IV one hour after stroke, has been shown to greatly reduce the percent stroke volume (%SV) in rabbits. With repeated doses its effect continued for 24 hours.

Purpose:

Test DDFPe as neuroprotective agent in permanent occlusion rat stroke models in Sprague Dawley (SD) and Spontaneously Hypertensive Rats (SHR) measuring both %SV and neurological assessment scores (NAS).

Methods:

The male rats received either saline (control), or one or four doses (1x or 4x) of DDFPe (0.6ml/kg IV) one hour post stroke. Treatment groups were SD (n=26) (control, 1x and 4x; n=12, 7 and 7) and SHR (n=14) (control, 1x and 4x; n=7, 3 and 4). The 4x doses were given at 1.5 hour intervals. At six hours post stroke, the rats received a NAS using standard tests for balance, reflexes, and motor performance. Then rats were euthanized and brains removed for TTC evaluation of %SV.

Results:

For %SV analysis strain differences were not significant therefore strains were combined. DDFPe significantly decreased %SV in 1x and 4xDDFPe groups compared to control groups (2.59±1.81 and 0.98±0.88 vs. 9.24±6.06, p≤0.001 each; p≤0.0001 for the overall test for treatment effect). The 1x versus 4xDDFPe groups were not significantly different (p=0.40). In NAS analysis both strains showed significant improvement with 4xDDFPe therapy vs. controls, (SD: 5.00+2.45 vs. 9.36+3.56, p=0.01; SHR: 7.75+4.43 vs. 12.14+3.08, p=0.05). Differences between the 1x DDFPe group and controls were not significant (SD: 8.43+3.69; SHR: 9. 33+3.51).

Conclusion:

DDFPe treatment provides significant neuroprotection when assessed six hours post stroke.

Progress in dodecafluoropentane emulsion as a neuroprotective agent in a rabbit stroke model

Dodecafluoropentane emulsion (DDFPe) in 250 nm nanodroplets seems to swell modestly to accept and carry large amounts of oxygen in the body at >29 °C. Small particle size allows oxygen delivery even into hypoxic tissue unreachable by erythrocytes. Using permanent cerebral embolic occlusion in rabbits, we assessed DDFPe dose response as a neuroprotectant at 7 and 24 h post-embolization without lysis of arterial obstructions and investigated blood pharmacokinetics. New Zealand White rabbits (N = 56) received cerebral angiography and embolic spheres (diameter = 700-900 μm) occluded middle and/or anterior cerebral arteries. Intravenous DDFPe dosing (2 % w/v emulsion) began at 60 min and repeated every 90 min until sacrifice at 7 or 24 h post-embolization. Seven-hour groups: (1) control (embolized without treatment, N = 6), and DDFPe treatment: (2) 0.1 ml/kg (N = 7), (3) 0.3 ml/kg (N = 9), (4) 0.6 ml/kg (N = 8). Twenty-four-hour groups: (5) control (N = 16), and DDFPe treatment: (6) 0.1 ml/kg (N = 10). Infarcts as percent of total brain volume were determined using vital stains on brain sections. Other alert normal rabbits (N = 8) received IV doses followed by rapid arterial blood sampling and GC-MS analysis. Percent infarct volume means significantly decreased for all DDFPe-treated groups compared with controls, p = <0.004 to <0.03. Blood DDFP (gas) half-life was 1.45 ± 0.17 min with R = 0.958. Mean blood clearance was 78.5 ± 24.9 ml/min/kg (mean ± SE). Intravenous DDFPe decreases ischemic stroke infarct volumes. Blood half-life values are very short. The much longer therapeutic effect, >90 min, suggests multiple compartments. Lowest effective dose and maximum effective therapy duration are not yet defined. Rapid development is warranted.

Mesenteric vein thrombosis treated successfully with ultrasound augmented thrombolysis

Mesenteric vein thrombosis is a potentially fatal condition that is associated with better outcomes with early diagnosis and intervention. A 32-year-old-man with Down syndrome presented with abdominal pain and was found to have extensive porto-splenomesenteric thrombosis with early bowel ischemia on computed tomography. He was treated successfully with ultrasound augmented thrombolysis. Ultrasound can improve efficiency of thrombolysis, decreasing the time required for thrombolysis by half, decrease thrombolytic dose and monitoring time and thus reduce overall costs and complications seen with long thrombolysis times.

Successful intravascular ultrasound thrombolysis of dural sinus thrombosis with pre-existing subarachnoid and intraparenchymal hemorrhages

A case of cerebral venous thrombosis with intraparenchymal and subarachnoid hemorrhages was initially treated unsuccessfully with mechanical and pharmacologic thrombolysis using intrathrombus tissue plasminogen activator (tPA) and angioplasty, and later successfully treated with an intravascular ultrasound tPA infusion catheter. This new microcatheter allowed direct infusion of tPA while using local therapeutic intravascular ultrasound to increase the thrombolytic effect. Flow was quickly restored. Our patient recovered from coma to discharge home without worsening of existing hemorrhages.

Microbubble potentiated ultrasound as a method of declotting thrombosed dialysis grafts: experimental study in dogs

Intravenous perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles in the presence of low frequency ultrasound (LFUS) can lyse very small clots. We develop a similar method to declot full-size arteriovenous dialysis grafts. Dialysis grafts fashioned in three dogs were cannulated and ligated. After thrombosis, three declotting techniques were randomly applied: 1) direct injection of PESDA + LFUS; 2) direct injection of saline + LFUS; and 3) intravenous PESDA + LFUS. Declotting was graded by cine angiography scores of each third of the graft on a scale of 0-4 (maximum total score = 12). Twenty-six procedures showed mean patency scores of 11.1 for direct PESDA and 8.4 for i.v. PESDA, vs 4.9 for direct saline, p = <0.001. All eight direct PESDA injections achieved lysis and good flow, but none of 8 direct saline injections succeeded, p = <0.01. Intravenous PESDA succeeded in 4 of 10 procedures, p = <0.04 vs saline. Direct injection of PESDA with transcutaneous LFUS succeeds in lysing moderate-size clots and recanalizing thrombosed fistulas.

Aortic prosthetic graft infections: radiologic manifestations and implications for management

Prosthetic graft infections are an uncommon complication of aortic bypass. These infections may have serious sequelae such as limb loss and can be lethal. They are hard to eradicate and, under certain circumstances, difficult to diagnose. Usually, computed tomography (CT) is the most efficacious imaging method for diagnosis of graft infections due to its quick availability. The sensitivity of magnetic resonance imaging in detection of perigraft infection has not been thoroughly investigated but is probably similar to that of CT. After the early postoperative period, persistent or expanding perigraft soft tissue, fluid, and gas are the CT findings of graft infection. Aortoenteric fistula should be considered a subset of aortic graft infection; however, perigraft air is more likely to be seen with an aortoenteric fistula. Other conditions associated with graft infection include pseudoaneurysm, hydronephrosis, and osteomyelitis. Adjunctive studies such as sinography, ultrasonography, gallium scanning, and labeled white blood cell scanning can be quite useful in diagnosis, determination of the extent of disease, and selection of the treatment modality. White blood cell scanning is an important complementary test to CT in ambiguous cases, such as in the early postoperative period, and may be more sensitive in detection of early graft infection.

Cardiac perforation and tamponade during transjugular intrahepatic portosystemic shunt placement

A patient developed acute severe hemodynamic compromise during a transjugular intrahepatic portosystemic shunt (TIPS) procedure for intractable ascites. Rapid clinical and radiographic evaluation of the patient disclosed pericardial blood and cardiac tamponade as the cause, probably due to right heart perforation from guidewire and catheter manipulation. The tamponade was successfully treated percutaneously, and the patient survived. Cardiac tamponade should be considered in the differential diagnosis of patients who develop hypotension during TIPS placement.

Relative ultrasonographic echogenicity of standard, dimpled, and polymeric-coated needles

PURPOSE

To use quantitative ultrasonographic measurements to compare the effect of a polymeric coating designed to increase needle echogenicity to commercially available needles.

MATERIALS AND METHODS

Commercially available standard smooth and dimpled echogenic tip 21-gauge needles established reference levels of echogenicity in gelatin-based and turkey breast phantoms. Examples of both types of needles were coated with a thin polymeric film that utilizes entrapped microbubbles of air on its surface to increase echogenicity. Samples of each type in both coated and noncoated versions were placed in phantoms in matched positions and imaged with clinical ultrasound machines. Similar numbers of each category were evaluated at various angles of insonation for a total of 109 images. Similar numbers of each category were imaged at 5-minute intervals for up to 38 minutes for a total of 226 images. Images were recorded, digitized, and evaluated for relative echo strength in arbitrary echogenic brightness units.

RESULTS

Coating increased peak echogenicity over the entire needle to a level that closely approximates the peak echogenicity of dimpled needle tips (means: dimpled = 834, coated smooth = 803, coated dimpled = 823; P = .54). Smooth is lower than this group at 468 (P = .0001). Representative area echogenicity increased with coating or dimpling (smooth = 377 vs coated smooth = 778, coated dimpled = 690, dimpled = 775; P = .0001). Coating increased peak values 74% and area values 95% compared to smooth. Decreased angles of insonation moderately reduced echogenicity on coated smooth, coated dimpled, and dimpled, while it decreased to below good visibility threshold on standard smooth needles. The echogenicity of the coated needles fades in saline with time (1%/min).

CONCLUSION

Objective measurements show that this coating significantly increases echogenicity of entire needles to match that obtained with a dimpled tip.

Comparison of hepatic damage from direct injections of iodinated contrast agents and carbon dioxide

PURPOSE

This study guides the choice of contrast agent for localization of portal veins during transjugular intrahepatic portosystemic shunt (TIPS) placement or use in percutaneous transhepatic cholangiography (PTC) by providing gross anatomic and histologic comparison of effects from parenchymal injections of iodinated contrast agents and carbon dioxide.

MATERIALS AND METHODS

Eighteen New Zealand White rabbits received direct injections of 2-5 mL of either the nonionic contrast agent iohexol 300 mgI or the ionic contrast agent diatrizoate meglumine 60% into one lobe of the liver and the same volume of CO2 into the other lobe. The rabbits were killed at 2-7 days for gross and histologic evaluation of the livers.

RESULTS

At the time of injection, the diatrizoate and iohexol sites showed persistent dark discoloration, whereas CO2 sites showed minimal visible changes. On gross examination at death, all diatrizoate sites showed severe scarring and also commonly showed areas of necrosis. CO2 and iohexol sites showed only minimal discoloration and needle-puncture scars (P < .0001). The histologic grade for diatrizoate sites was significantly more severe than paired CO2 sites (P < .016). Iohexol sites showed mild histologic changes similar to paired CO2 sites (P = .375).

CONCLUSION

Iohexol and CO2 produce less severe hepatic damage and are preferred to meglumine diatrizoate for hepatic injection.

Complications and technical limitations of hepatic arterial infusion catheter placement for chemotherapy

PURPOSE

To determine the rate of complications associated with hepatic arterial infusion (HAI) catheter placement, as well as technical success related to liver perfusion.

MATERIALS AND METHODS

The authors reviewed 44 patients who underwent 106 HAI catheter placements, including 15 men and 29 women with an average age of 55 years (range, 32-82 years). One to nine placements were performed per patient with 61 (58%) via the left brachial artery, 40 (38%) via the right femoral artery, and five (4%) via the left femoral artery. Chemoinfusion lasted 4 days, with initial catheter placement assessed on technetium-99m macroaggregated albumin (MAA) perfusion scans, as well as daily abdominal radiographs.

RESULTS

One hundred attempted hepatic arterial catheter placements were completed. Liver perfusion was global in 66 (66%) cases, in the right lobe only in 28 (28%) cases, and in the left lobe only in six (6%) cases. Eight (8%) had gastrointestinal (GI) tract perfusion; this was eliminated in seven cases (7%) after catheter repositioning. Forty-six (43%) placement attempts required embolization of 62 GI vessels to preclude GI chemoinfusion. Complications included one cerebrovascular accident (related to removal of a left brachial catheter), eight brachial artery thromboses (four that required emergent thrombectomy), six hepatic arterial dissections, four hepatic arterial thromboses, and four catheter malfunctions.

CONCLUSIONS

HAI catheter placement via the left brachial artery has increased complications. Nearly one-half of placements required embolization of GI vessels to preclude GI perfusion. Global perfusion is possible in two-thirds of cases.

Utility of magnetic resonance arteriography for distal lower extremity revascularization

PURPOSE

Magnetic resonance arteriography (MRA) of the lower extremities affords several possible advantages over conventional contrast arteriography (CA). We hypothesized that MRA of the infrageniculate vessels was sufficiently accurate to replace CA before revascularization procedures in patients with limb-threatening ischemia.

METHODS

Fifty-three extremities in 49 patients were prospectively evaluated before attempted infrageniculate revascularization procedures with preoperative infrageniculate time-of-flight MRA (cost, $170/study) and standard contrast arteriography (cost, $1310/study) of the aortoiliac and runoff vessels. Independent operative plans were formulated based on the MRA and CA results before the revascularization procedure. Intraoperative, prebypass arteriograms (IOA; cost, $46/study) were obtained in all patients to confirm the adequacy of the distal runoff. The preoperative plans formulated by the results of MRA and CA were compared with the actual procedure performed based on the IOA. All arteriograms (CA, MRA, IOA) were reviewed after the operation by two independent reviewers, and the number of patent vessel segments and those with < 50% stenosis was determined.

RESULTS

Revascularization procedures were performed in 44 of 53 extremities (83%), and amputation was performed in nine extremities (17%) because of an absence of a suitable bypass target. The CA and MRA were equally effective in predicting the optimal operative plans as determined from IOA (CA, 42 of 53 [77%] vs MRA, 40 of 53 [75%]; p = 0.79). More patent vessel segments were seen on CA than MRA (reviewer A, 229 vs 174, kappa = 0.32; reviewer B, 321 vs 314, kappa = 0.46); however, a comparable number of segments were seen if the vessels of the foot were excluded. The accuracy (reviewer A, 78% vs 68%, p = 0.003; reviewer B, 75% vs 67%, p = 0.003) and sensitivity (reviewer A, 69% vs 51%, p = 0.001; reviewer B, 68% vs 46%, p = 0.0001) of CA relative to IOA were superior to those of MRA, although the specificity was comparable (reviewer A, 86% vs 90%, p = 0.31; reviewer B, 82% vs 87%, p = 0.52). The combination of MRA and IOA would have resulted in the optimal operative plan in 51 of the 53 cases (96%) and was comparable with CA and IOA (53 of 53; 100%; p = 0.50). Substitution of MRA and IOA for CA and IOA could potentially have saved an estimated $60,420.

CONCLUSIONS

The combination of MRA and IOA provides an accurate, cost-efficient strategy for visualization of the infrageniculate vessels before revascularization procedures.

Intraoperative prebypass arteriography for infrageniculate revascularization

BACKGROUND

Selection of the optimal distal target for infrageniculate arterial revascularization remains difficult in patients with multilevel occlusive disease due to poor visualization of the distal vasculature by preoperative arteriography. Prebypass, intraoperative arteriography (IOA) with direct injection of contrast into the infrageniculate arteries may improve distal arterial visualization and bypass target selection.

METHODS

One hundred fourteen extremities in 104 consecutive patients requiring infrageniculate bypass were prospectively studied. All patients underwent preoperative contrast arteriography (CA) of the aortoiliac and lower extremity arteries using iodinated and/or CO2 contrast and digital subtraction techniques. IOAs were obtained at operation to confirm the adequacy of the distal runoff from the predicted bypass target and to identify potentially superior targets. The preoperative plan formulated from the CA was compared to the actual procedure performed based on the IOA. The CA and IOA were also independently reviewed postoperatively by two blinded vascular surgeons to determine the number of patent vessel segments visualized and the number of segments with <50% stenosis.

RESULTS

Revascularization was done in 105 of 114 extremities (92%), whereas amputation was required as the initial procedure in 9 patients (8%). The IOA altered the operative plan based on the CA in 27 of 144 patients (24%). Changes in the planned bypass procedures included selection of a more distal anastomotic site in 13 of 102 patients (13%), selection of a more proximal anastomotic site in 4 of 102 (4%), selection of a different artery for the distal anastomosis in 3 of 102 (3%), and amputation rather than bypass in 2 of 102 patients (2%) with no suitable distal bypass target on the IOA. The IOA also resulted in bypass rather than planned amputation in 5 of 12 patients (42%) deemed unreconstructable on the preoperative CA. A mean of 13 minutes was required for IOA and an adequate study was obtained on the first attempt in 98 of 144 patients (86%). On postoperative review, more patent vessel segments but fewer segments with <50% stenosis were identified on the IOA compared to the CA.

CONCLUSIONS

Prebypass intraoperative arteriography facilitates selection of the optimal distal bypass target during infrageniculate revascularization and can result in initial limb salvage in select patients deemed unreconstructable by preoperative contrast arteriography.

Biliary strictures in liver transplant recipients: treatment with metal stents

PURPOSE

To determine initial and long-term results of metal stent placement in biliary strictures that failed to respond to balloon dilation.

MATERIALS AND METHODS

Sixty-one metal stents were placed in 36 liver transplant recipients (age range, 3 months to 71 years) with biliary strictures that failed to respond to balloon dilation. Patients were followed up for up to 5 years.

RESULTS

Initial stent placement was successful in all patients. Primary patency was 44% at 3 years and was 0% at 5 years; secondary patency was maintained at 88% at those intervals. Patency associated with the Gianturco Z stent was superior to that with the Palmaz stent. Stents located at anastomotic sites had higher patency rates than those at nonanastomotic sites. Major stent-related complications occurred in eight patients and included two pediatric deaths.

CONCLUSION

Metal stents can be useful in the short term but have limited patency, often require repeat intervention, and have substantial complications. Long-term success depends heavily on repeat interventions or stent removal.

Buoyancy of gallstones in varying concentrations of contrast media

Gallstones from 100 patients were tested for buoyancy in four concentrations of contrast materials commonly used in the biliary tree. In 7 1/2% iodine, fully 68% of the patients' stones floated; in 15% iodine, 82% floated; in 30% iodine, 93% floated; and in 38% iodine, 95% floated. This can lead to confusion with bubbles of air, either when stones are mechanically or hydraulically dislodged or when simple buoyancy of high concentrations of iodine floats stones from their usual location held by accretions and inflammatory reaction in the distal common duct. When floating stones are a problem, as often occurs during percutaneous stone removal, substitution of the most dilute contrast material visible and the use of very low kilovoltage should help in one-fourth of cases.

Changing normal values for thyroid uptake of radioactive iodine

The 24-hour radioactive iodine uptake remains a very useful clinical tool for evaluating the thyroid gland; however, the normal values have changed over the years. The traditional values of 15% to 45% are clearly not applicable today and the revised values of 9% to 32% are suspect in some areas where iodine content is rapidly changing in the general diet. The values in a relatively stable population in Ft. Smith, Arkansas, without significant access to a continuous-batch bread with a high iodine content do confirm the national trend of the early 1970's suggesting an overall normal range from 11% to 30%. Values in men were found to be lower with a range from 11% to 23%, whereas in women the values ranged from 13% to 32%. Each nuclear medicine department should be responsible for establishing its own normal range and reevaluating it on a fairly routine basis-certainly whenever known dietary iodine factors change.

Releif of severe fecal impactions with water-soluble contrast enemas

High fecal impaction resulted in complete bowel obstruction in 2 children following renal transplantation and in one adult on chemotherapy and narcotics. The usual methods of relief failed, and water-soluble contrast enemas with a high osmolality were employed. Fluoroscopic control assured placement of the enema fluid at the site of obstruction, where it was very effective in relieving the impaction. It is suggested that such high-osmolality enemas be considered in patients with severe high fecal impactions before surgery is contemplated.