Timothy C. McCowan

Quality Improvement Guidelines for Percutaneous Management of the Thrombosed or Dysfunctional Dialysis Access

John E. Aruny, MD, Curtis A. Lewis, MD, John F. Cardella, MD, Patricia E. Cole, PhD, MD, Andrew Davis, MD, Alain T. Drooz, MD, Clement J. Grassi, MD, Richard J. Gray, MD, James W. Husted, MD, Michael Todd Jones, MD, Timothy C. McCowan, MD, Steven G. Meranze, MD, A. Van Moore, MD, Calvin D. Neithamer, MD, Steven B. Oglevie, MD, Reed A. Omary, MD, Nilesh H. Patel, MD, Kenneth S. Rholl, MD, Anne C. Roberts, MD, David Sacks, MD, Orestes Sanchez, MD, Mark I. Silverstein, MD, Harjit Singh, MD, Timothy L. Swan, MD, Richard B. Towbin, MD, Scott O. Trerotola, MD, Curtis W. Bakal, MD, MPH, for the Society of Interventional Radiology Standards of Practice Committee

Quality Improvement Guidelines for Percutaneous Transhepatic Cholangiography and Biliary Drainage

PERCUTANEOUS transhepatic cholangiography is a safe and effective technique for evaluating biliary abnormalities. It reliably demonstrates the level of abnormalities and sometimes can help diagnose their etiologies. Percutaneous transhepatic biliary drainage is an effective method for the primary or palliative treatment of many biliary abnormalities demonstrated with cholangiography. Participation by the radiologist in patient follow-up is an integral part of percutaneous transhepatic biliary drainage and will increase the effectiveness of the procedure. Close follow-up, with monitoring and management of the patients’ drainage-related problems, is appropriate for the interventional radiologist. These guidelines are written to be used in quality improvement programs to assess percutaneous biliary procedures. The most important processes of care are (a) patient selection, (b) performing the procedure, and (c) monitoring the patient. The outcome measures or indicators for these processes are indications, success rates, and complication rates. Outcome measures are assigned threshold levels.

Results of a multicenter study of the modified hook-titanium Greenfield filter

Initial efforts to modify the stainless steel Greenfield filter for percutaneous insertion led to development of a titanium Greenfield filter, which could be inserted by use of a 12F carrier. This device functioned well as a filter but had an unacceptable 30% rate of migration, tilting, and penetration. Therefore a titanium Greenfield filter with modified hooks was developed and has been tested in 186 patients at 10 institutions. Successful placement occurred in 181 (97%); placement of the remainder was precluded by unfavorable anatomy. A contraindication to anticoagulation was the most frequent indication for insertion (75%). All but two were inserted percutaneously, predominantly via the right femoral vein (70%). Initial incomplete opening was seen in four patients (2%), which was corrected by guide wire manipulation and asymmetry of the legs in 10 (5.4%). Insertion site hematoma occurred in one patient, and apical penetration of the cava during insertion occurred in a second patient. Both events were without sequelae. Follow-up examinations were performed at 30 days at which time 35 deaths had occurred. Recurrent embolism was suspected in six patients (3%) and two of three deaths were confirmed by autopsy. Filter movement greater than 9 mm was seen in 13 patients, (11%) and increase in base diameter greater than or equal to 5 mm was seen in 17 patients (14%). CT scanning showed evidence of caval penetration in only one patient (0.8%). Insertion site venous thrombosis was seen in 4/46 (8.7%) patients screened. The modified hook titanium Greenfield filter is inserted percutaneously or operatively through a sheath, eliminating concern for misplacement from premature discharge.(ABSTRACT TRUNCATED AT 250 WORDS)

Quality improvement guidelines for transjugular intrahepatic portosystemic shunts.

Ziv J. Haskal, MD, Louis Martin, MD, John F. Cardella, MD, Patricia E. Cole, PhD, MD, Alain Drooz, MD,Clement J. Grassi, MD, Timothy C. McCowan, MD, Steven G. Meranze, MD, Calvin D. Neithamer, MD,Steven B. Oglevie, MD, Anne C. Roberts, MD, David Sacks, MD, Mark I. Silverstein, MD,Timothy L. Swan, MD, Richard B. Towbin, MD, and Curtis A. Lewis, MD, MBA, for the Society ofInterventional Radiology Standards of Practice Committee

Complications of the Nitinol Vena Caval Filter

Simon nitinol vena caval filters were placed percutaneously in 20 patients. Follow-up (average, 14 months) data were available for 16 patients, and four patients were lost to follow-up. There were no proved or suspected cases of pulmonary embolism after filter insertion. Complications encountered included caval penetration (n = 5, one acute and four at follow-up), caval thrombus (n = 4, two determined radiologically and two clinically), postplacement deep venous thrombosis (n = 2, one radiologic and one clinical), filter migration (n = 1), and delayed fracture of a filter leg (n = 2). Although no deaths or significant morbidity resulted from any complication, the relatively high complication rate, especially of significant caval penetration (documented in 25% of filter insertions), merits continued short- and long-term assessment of patient status after filter placement.

LGM Vena Cava Filter: Objective Evaluation of Early Results

One hundred one LG-Medical (LGM) vena cava filters were placed in 97 patients at four institutions. Placement was a complete technical success in 90% (91 of 101). In 6% of attempts, LGM filter insertion was complicated by incomplete opening of the filter. Pulmonary embolism after filter placement was not definitely demonstrated in any patient. The probability of inferior vena cava patency was 92% at 6 months after filter insertion. Thrombosis at the insertion site was seen in eight of 35 patients (23%) evaluated with duplex ultrasound or venography. Thrombus was observed in 37% of filters at follow-up examination, with cephalic extension of thrombus above the filter in 20% of all patients examined. Filter migration (greater than 1 cm) was seen in 12%; significant angulation was observed in only one patient (2%). In vitro experimentation demonstrated that incomplete opening of the LGM filter during placement can be avoided, in part, by brisk retraction of the insertion cannula. The low-profile introducer system of the LGM filter allows increased alternatives in selecting the site for filter insertion. The low-profile system also makes outpatient filter placement a possibility. No significant difference in the prevalence of thrombosis at the insertion site following LGM filter insertion was noted compared with previous results reported for percutaneous transfemoral placement of the Greenfield filter. The nonopaque sheath does not permit careful localization prior to filter deposition. Modification of the LGM filter to include a radiopaque sheath is suggested.

Route of hepatocyte delivery affects hepatocyte engraftment in the spleen1

In laboratory animals, intrasplenic hepatocyte transplantation corrects the physiologic abnormalities associated with decompensated liver disease. The clinical experience with hepatocyte transplantation for cirrhosis has been disappointing when compared with laboratory experience. The route of hepatocyte delivery may influence hepatocyte engraftment and function. Outbred pigs were recipients of allogeneic pig hepatocytes. Donor hepatocytes were isolated by collagenase perfusion and labeled using 5(6)-carboxyfluorescein diacetate succinimidyl-ester (CMFSE). Cells were introduced into pig spleens by infusion through the splenic artery or by direct splenic puncture. Direct intrasplenic injection produced engraftment that was far superior to that obtained using splenic artery infusion. Splenic artery infusion produced a gastric erosion and large areas of splenic necrosis secondary to vascular occlusion with hepatocytes, whereas direct splenic injection was associated with clinically insignificant intraabdominal hemorrhage. The route of hepatocyte delivery may influence hepatocyte engraftment and explain the disparity in efficacy of hepatocyte transplantation between the laboratory and clinic.

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.

Microbubble-augmented Ultrasound Declotting of Thrombosed Arteriovenous Dialysis Grafts in Dogs

PURPOSE Transcutaneous low-frequency ultrasound (LFUS) can effectively lyse clots in the presence of microbubbles. This study was designed to test the commercially available human albumin microspheres injectable suspension octafluoropropane formulation, Optison, to establish efficacy and assess US parameters of intensity and wave modes in a canine model of a thrombosed arteriovenous (dialysis) graft. MATERIALS AND METHODS Arteriovenous grafts in five dogs were cannulated, temporarily ligated, and thrombosed. Different declotting techniques were randomized to treat nine groups. Control groups involved direct saline (4.5 mL) clot injection in 0.5-1.0-mL increments. One group underwent peripheral intravenous microbubble injection (13.5 mL). Six groups underwent direct incremental clot injection of 4.5 mL of microspheres with LFUS for 30 minutes in 3-5-minute increments with use of various intensity settings in continuous-wave and pulsed-wave (PW) modes. At each increment, angiography was used to grade flow, declotting, and overall success. RESULTS One hundred four procedures showed success in all 24 high-intensity PW modes (1.2-2.0 W/cm(2)); only one of 20 control experiments was successful (P <.0001). Medium-intensity modes yielded intermediate success rates. Lowest-intensity direct-injection groups and intravenous and control groups ranked lower. Results at 30 minutes were better than at 15 minutes (P <.0001). CONCLUSIONS LFUS with direct injection of microbubbles is effective in lysing moderate-sized clots and recanalizing thrombosed arteriovenous grafts. It best succeeds at the higher range of intensity settings tested in PW mode. Further development is justified.

Microbubble Potentiated Ultrasound as a Method of Declotting Thrombosed Dialysis Grafts: Experimental Study in Dogs

AbstractIntravenous 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 IV 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.