Moni Stein

Symptomatic spleno-mesenteric-portal venous thrombosis: recanalization and reconstruction with endovascular stents.

PURPOSE To evaluate the safety and efficacy of portal reconstruction in patients with symptomatic spleno-mesenteric-portal venous thrombosis. MATERIALS AND METHODS Portal reconstruction was attempted in 21 patients (seven women, 14 men; mean age, 53.6 years +/- 15.2) with chronic thrombosis of the portal vein alone (n = 8), splenic vein alone (n = 3), or portal, mesenteric, and splenic veins (n = 10). Indications for the procedure were bleeding varices (n = 15), ascites (n = 2), hypersplenism (n = 2), and enteropathy (n = 2). Sixteen procedures were started transhepatically and of these seven were converted to a transjugular intrahepatic portosystemic shunt (TIPS) after successful recanalization of the thrombosed vein. In six patients reconstructions were performed using an intrahepatic portal vein as outflow. Five procedures were performed primarily as TIPS. Wallstents dilated to 7-10 mm were used for reconstruction. The mean follow-up period was 15.2 months +/- 15.9. RESULTS Technical success of portal reconstruction was 85.7% (18 of 21). Thirty-day mortality was 14.3% (three of 21) but was not procedural related. The cumulative rates of survival, primary patency, and palliation at 43 months of follow-up were 61.2% +/- 13.5%, 63.5% +/- 15.3%, and 31.7% +/- 15.7%, respectively. Secondary patency was 79.1% +/- 13.8%. The only predictor of mortality was the presence of liver disease (P = .001, Cox regression). CONCLUSION Portal reconstruction is a safe and effective treatment option for patients with symptomatic chronic portal thrombosis. Liver disease predisposes to a higher mortality.

Effects of Brachytherapy on Intimal Hyperplasia in Arteriovenous Fistulas in a Porcine Model

PURPOSE The hypotheses of this investigation were that endovascular radiation would reduce intimal hyperplasia in arteriovenous fistulas (AVFs) and that this reduction would be associated with decreased expression of vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF)-A, and tumor necrosis factor (TNF)-alpha. MATERIALS AND METHODS Bilateral end jugular vein-to-side carotid artery fistulas were constructed in pigs. At 48 hours, one AVF was randomly selected for endovascular radiation with (192) Iridium. The contralateral fistula received no radiation and served as a control. Animals in group 1 (n = 7) received 14 Gy of radiation at a depth of 2 mm and tissue was harvested at 29 days; animals in group 2 received 7 Gy of radiation at a depth of 2 mm and tissue was harvested at 29 days (n = 8); and animals in group 3 received 7 Gy of radiation at a depth of 2 mm and tissue was harvested at 56 days (n = 8). The area and maximum thickness of intimal hyperplasia were then measured blindly. Immunohistochemical results for VEGF, PDGF-A, and TNFalpha were obtained and analyzed blindly by assigning a score of 0-3, with 0 indicating no staining and 3 indicating maximum staining. RESULTS Irradiation with 14 Gy caused severe fibrosis in the media of the vein, with thrombosis of three of seven AVFs. Compared with the control group, the group that underwent irradiation with 7 Gy had significantly reduced intimal area at 56 days (9.9 mm(2) +/- 4.9 vs 2.1 mm(2) +/- 1.1; P =.001). This reduction correlated with significant reduction in the expression of VEGF (score of 2.2 +/- 0.1 vs 1.2 +/- 0.2; P =.001) and TNFalpha (1.3 +/- 0.1 vs 0.9 +/- 0.1; P =.04). CONCLUSION Fourteen grays is an excessive radiation dose for veins, causing medial fibrosis and thrombosis of the AVF. Irradiation with 7 Gy effectively inhibited the formation of intimal hyperplasia in AVF. This inhibition correlated with decreased expression of VEGF and TNFalpha.

Percutaneous transhepatic portography with intravascular ultrasonography for evaluation of venous involvement of hepatobiliary and pancreatic tumors

PURPOSE To determine the safety and utility of percutaneous transhepatic portography (PTP) with intravascular ultrasonography (IVUS) for preoperative evaluation of major spleno-mesenteric-portal venous invasion by tumors of the pancreas, porta hepatis, or liver. MATERIALS AND METHODS This is a 2-year prospective observational study including 15 consecutive patients (five men, 10 women; mean age, 63.3 y +/- 10.2) with tumors of the pancreas (n = 8), liver (n = 3), or porta hepatis (n = 4) who underwent PTP/IVUS after computed tomography indicated possible tumor invasion into a major portal radical. Transhepatic portal access was created under fluoroscopic guidance with an 8-F vascular sheath and IVUS was performed with an 8-F, 10-MHz system. When appropriate, operative exploration was performed (nine of 15) and findings were correlated with imaging data from PTP/IVUS. RESULTS PTP/IVUS was performed successfully in all patients and good visualization of the major portal radicals was achieved. There were no complications from PTP/IVUS, which was performed as an outpatient procedure in most (n = 14) patients. PTP/IVUS provided precise anatomic data regarding the longitudinal and circumferential extent of major portal venous invasion by these tumors. There was excellent correlation between PTP/IVUS and operative findings. CONCLUSIONS PTP/IVUS can be performed safely in a preoperative outpatient setting and accurately defines the extent of major portal venous invasion by tumors of the pancreas, porta hepatis, and liver.

Corpus cavernosum as an emergency vascular access in dogs

RATIONALE AND OBJECTIVES We investigated the feasibility of using the corpus cavernosum as an emergency vascular access in dogs with severe hypovolemia. METHODS Five male mongrel dogs were brought to hypovolemic shock by withdrawal of blood through an internal jugular venous line. Using the corpus cavernosum as a venous access, normal saline was injected through a 23-gauge needle at the highest possible rate. Cavernosography was performed under fluoroscopy to verify the accurate position of the needle tip. Blood volumes were measured using 125I-labeled human serum albumin. RESULTS Before the dogs were bled, their mean systolic blood pressure was 121.4 (mean) +/- 5.2 (standard error) mm Hg and their mean blood volume was 1,835.2 +/- 139.7 ml. The mean volume of blood removed from the dogs was 710.0 +/- 67.8 ml. The mean systolic pressure during shock was 40.8 +/- 2.2 mm Hg. After fluid resuscitation, the mean systolic pressure recovered to 114.6 +/- 4.6 mm Hg and their mean blood volume increased to 1,763.2 +/- 112.7 ml. The mean rate of saline infusion into the corpus cavernosum was 50.2 +/- 0.7 ml/min. CONCLUSION The results of this study demonstrate the feasibility of using the corpus cavernosum as an alternative route for fluid resuscitation in severely hypovolemic dogs.

Young Investigator Award: Percutaneous Facet Joint Fusion: Preliminary Experience

PURPOSE The synovium-lined apophysial joint is an important cause of back pain through facet arthrosis and nerve root pressure. The short-term results of two relatively noninvasive treatments--facet block and facet rhizotomy--have been better than their long-term results. The authors propose treatment with fusion of the posterior facet joints in the lumbar spine by means of a simple percutaneous procedure performed under local anesthetic with use of radiologic guidance. MATERIALS AND METHODS In the first phase of this study the technical feasibility of the concept was established in human cadaver spine. In the second phase a canine model was tested in which bone grafts were surgically inserted into lumbar facet joints. Five male and two female mongrel dogs, weighing 18-25 kg (mean, 20.3 kg), were operated on. Each procedure was done in three steps: First, preoperative computed tomographic (CT) scans were obtained to measure facet depth. Second, surgery was performed under fluoroscopic guidance with use of a threaded guide wire, a small cannulated coaxial drilling system, and hydroxyapatite cancellous bone plugs. Third, early postoperative CT scans were obtained to verify bone plug location. CT was repeated at 4 and 6 months after surgery to check for fusion. The dogs were killed at 6 months, and histologic examination was performed. RESULTS Successful insertion of the bone plug was achieved in 12 of the 14 facets (86%). One dog died as a complication of the procedure. Fusion occurred in five of the 12 surgically treated facets (42%). CONCLUSION Drilling and surgical insertion of bone plugs into facet joints of dogs were feasible. The fusion results are promising and may improve with future modifications of the technique.

Angiographic Assessment of Arterial Outflow: Predictive Value of a New Classification System☆

A prospective study with 4 years of follow-up involving 127 consecutive symptomatic patients (60.6% with claudication, 39.4% with critical ischemia) who underwent aortobifemoral bypass surgery is described. A new grading system for the classification of arterial outflow was applied to determine its usefulness in predicting the outcome of surgery. Preoperative angiograms were numerically scored according to the arterial outflow status at the level of main segmental involvement. Higher scores corresponded to worse outflows. Outflow scores ranged between 1 and 10 with a mean of 3.6 +/- 0.24. The main comparison was between patients with scores of less than 5 (group A, n = 80) and patients with scores of 5 or more (group B, n = 47). Better outflow was associated with higher postoperative mean increases in the ankle-brachial index (ABI) (group A, 0.35 +/- 0.03; group B, 0.17 +/- 0.04; P less than .001) and transcutaneous oximetry (PtcO2) (group A, 15.4 mm Hg +/- 1.8; group B, 8.4 mm Hg +/- 3.0; P = .01). At 4-year follow-up, group A had higher cumulative rates of patency (98.3% vs 78.0%, P less than .001), symptomatic relief (84.0% vs 23.3%, P less than .001), and palliation (67.0% vs 19.9%, P less than .001). In conclusion, angiographic outflow, as evaluated with the system described, successfully helped predict postoperative increases in ABI and PtcO2 and the cumulative rates of graft patency, symptomatic relief, and palliation.

TIPS Reduces Hepatic Asialoglycoprotein Receptor Concentration in Healthy Pigs

PURPOSE Technetium-99m-labeled diethylenetriamine pentaacetic acid galactosyl human serum albumin (TcGSA), a new agent for liver scintigraphy, is selectively attached to asialoglycoprotein receptors on liver cell membranes. A direct correlation exists between asialoglycoprotein receptor concentration, [R]o and hepatic functional reserve. The purpose of this study was to determine the effects of transjugular intrahepatic portosystemic shunting (TIPS) on hepatic asialoglycoprotein receptor concentration in pigs without liver parenchymal disease. MATERIALS AND METHODS TIPS was performed in eight pigs with use of a single 10-mm-wide x 68-mm-long Wallstent dilated to 10 mm. TcGSA dynamic imaging studies were performed before and twice after (7 and 14 days) TIPS. To be included in the study, pigs had to have a patent TIPS at 1 week of follow-up. Liver function tests were drawn parallel to the TcGSA studies. Liver biopsies were performed at 2 weeks when the animals were killed. RESULTS Five of the eight pigs had open shunts at 1 week and were included in the study. There was a significant (P < .0001, Student t test) difference between the mean [R]o of the pre-TIPS studies ([R]o = 1.12+/-0.04 microM) and the mean of the post-TIPS studies at 7 days ([R]o = 0.40+/-0.04 microM) and 14 days ([R]o = 0.51+/-0.06 microM, P < .01). The only blood test that was abnormal after TIPS was ammonia (mean, 129.0+/-42.7). Liver biopsies were normal. CONCLUSIONS TIPS reduces asialoglycoprotein receptor concentration in normal pigs.