Transjugular intrahepatic portosystemic shunt versus H-graft portacaval shunt in the management of bleeding varices: a cost-benefit analysis.

BACKGROUND: Transjugular intrahepatic portosystemic shunt (TIPS) is popular in treating portal hypertension because of its perceived efficacy and cost benefits, although it has never been compared with surgical shunting in a cost-benefit analysis. This study was undertaken to determine the cost benefit of TIPS versus small-diameter prosthetic H-graft portacaval shunt (HGPCS). METHODS: Cost of care was determined in 80 patients prospectively randomized to receive TIPS or HGPCS as definitive treatment for bleeding varices, beginning with shunt placement and including subsequent admissions for complications or follow-up related to shunting. RESULTS: Patients were similar in age, gender, severity of illness/liver dysfunction, and urgency of shunting. After TIPS or HGPCS, variceal rehemorrhage (8 versus O, respectively; p = 0.03), shunt occlusion (13 versus 4; p = 0.03), shunt revision (16 versus 4; p < 0.005), and shunt failure (18 versus 10; p = 0.10) were compared; all were more common after TIPS. Through the index admission, TIPS cost $48,188 +/- $43,355 whereas HGPCS cost $61,552 +/- $47,615. With follow-up, TIPS cost $69,276 +/- $52,712 and HGPCS cost $66,034 +/- $49,118. CONCLUSIONS: Early cost of TIPS was less than, though not different from, cost of HGPCS. With follow-up, costs after TIPS mounted. The initially lower cost of TIPS is offset by higher rates of subsequent occlusion and rehemorrhage.

Transjugular intrahepatic portosystemic shunt vs. small-diameter prosthetic H-graft portacaval shunt: extended follow-up of an expanded randomized prospective trial.

We report herein the results of extended follow-up of an expanded randomized clinical trial comparing transjugular intrahepatic portosystemic shunt (TIPS) to 8 mm prosthetic H-graft portacaval shunt as definitive treatment for variceal bleeding due to portal hypertension. Beginning in 1993, through this trial, both shunts were undertaken as definitive therapy, never as a "bridge to transplantation." All patients had bleeding esophageal/gastric varices and failed or could not undergo sclerotherapy/banding. Patients were excluded from randomization if the portal vein was occluded or if survival was hopeless. Failure of shunting was defined as inability to shunt, irreversible shunt occlusion, major variceal rehemorrhage, hepatic transplantation, or death. Median follow-up after each shunt was 4 years; minimum follow-up was 1 year. Patients undergoing placement of either shunt were very similar in terms of age, sex, cause of cirrhosis, Child's class, and circumstances of shunting. Both shunts provided partial portal decompression, although the portal vein-inferior vena cava pressure gradient was lower after H-graft portacaval shunt (P < 0.01). TIPS could not be placed in two patients. Shunt stenosis/occlusion was more frequent after TIPS. After TIPS, 42 patients failed (64%), whereas after H-graft portacaval shunt 23 failed (35%) (P < 0.01). Major variceal rehemorrhage, hepatic transplantation, and late death were significantly more frequent after TIPS (P < 0.01). Both TIPS and H-graft portacaval shunt achieve partial portal decompression. TIPS requires more interventions and leads to more major rehemorrhage, irreversible occlusion, transplantation, and death. Despite vigilance in monitoring shunt patency, TIPS provides less optimal outcomes than H-graft portacaval shunt for patients with portal hypertension and variceal bleeding.

Thermal decomposition of generation-4 polyamidoamine dendrimer films: decomposition catalyzed by dendrimer-encapsulated Pt particles.

The thermal decomposition of hydroxyl-terminated generation-4 polyamidoamine dendrimer (G4OH) films deposited on Au surfaces has been compared with decomposition of the same dendrimer encapsulating an approximately 40-atom Pt particle (Pt-G4OH). Infrared absorption reflection spectroscopy studies showed that, when the films were heated in air to various temperatures up to 275 degrees C, the disappearance of the amide vibrational modes occurred at lower temperature for the Pt-G4OH film. Dendrimer decomposition was also investigated by thermogravimetric analysis (TGA) in both air and argon atmospheres. For the G4OH dendrimer, complete decomposition was achieved in air at 500 degrees C, while decomposition of the Pt-G4OH dendrimer was completed at 400 degrees C, leaving only platinum metal behind. In a nonoxidizing argon atmosphere, a greater fraction of the G4OH decomposed below 300 degrees C, but all of the dendrimer fragments were not removed until heating above 550 degrees C. In contrast, Pt-G4OH decomposition in argon was similar to that in air, except that decomposition occurred at temperatures approximately 15 degrees C higher. Thermal decomposition of the dendrimer films on Au surfaces was also studied by temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) under ultrahigh vacuum conditions. Heating the G4OH films to 250 degrees C during the TPD experiment induced the desorption of large dendrimer fragments at 55, 72, 84, 97, 127, 146, and 261 amu. For the Pt-G4OH films, mass fragments above 98 amu were not observed at any temperature, but much greater intensities for H(2) desorption were detected compared to that of the G4OH film. XPS studies of the G4OH films demonstrated that significant bond breaking in the dendrimer did not occur until temperatures above 250 degrees C and heating to 450 degrees C caused dissociation of C=O, C-O, and C-N bonds. For the Pt-G4OH dendrimer films, carbon-oxygen and carbon-nitrogen bond scission was observed at room temperature, and further decomposition to atomic species occurred after heating to 450 degrees C. All of these results are consistent with the fact that the Pt particles inside the G4OH dendrimer catalyze thermal decomposition, allowing dendrimer decomposition to occur at lower temperatures. However, the Pt particles also catalyze bond scission within the dendrimer fragments so that decomposition of the dendrimer to gaseous hydrogen is the dominant reaction pathway compared to desorption of the larger dendrimer fragments observed in the absence of Pt particles.

Radiologic and pathologic characteristics of the WDHA syndrome.

A case of a non-beta islet cell tumor of the pancreas that produced the WDHA (watery diarrhea, hypokalemia, and achlorhydria) syndrome is presented. An enlarged body-tail region of the pancreas is demonstrated on transaxial views; multiple fluid-filled loops of small and large bowel are also noted. The angiography of the tumor is similar to other non-beta islet cell lesions consisting of a large hypervascular mass with hypertrophied feeding vessels and a persistent, dense capillary stain. The demonstration of elevated levels of vasoactive intestinal polypeptide in both tumor and plasma and the ultrastructural description of endocrine granules may help to explain the pathophysiology in this case.

Differential effects on portal and effective hepatic blood flow. A comparison between transjugular intrahepatic portasystemic shunt and small-diameter H-graft portacaval shunt.

OBJECTIVE: This study was undertaken to determine the effects of transjugular intrahepatic portasystemic shunt (TIPS) and small-diameter prosthetic H-graft portacaval shunt (HGPCS) on portal and effective hepatic blood flow. SUMMARY BACKGROUND DATA: Mortality after TIPS is higher than after HGPCS for bleeding varices. This higher mortality is because of hepatic failure, possibly a result of excessive diminution of hepatic blood flow. METHODS: Forty patients randomized prospectively to undergo TIPS or HGPCS had effective hepatic blood flow determined 1 day preshunt and 5 days postshunt using low-dose galactose clearance. Portal blood flow was determined using color-flow Doppler ultrasound. RESULTS: Treatment groups were similar in age, gender, and Child's class. Each procedure significantly reduced portal pressures and portasystemic pressure gradients. Portal flow after TIPS increased (21 mL/second +/- 11.9 to 31 mL/second +/- 16.9, p < 0.05), whereas it remained unchanged after HGPCS (26 mL/second +/- 27.7 to 14 mL/second +/- 41.1, p = n.s.). Effective hepatic blood flow was diminished significantly after TIPS (1684 mL/minute +/- 2161 to 676 mL/minute +/- 451, p < 0.05) and was unaffected by HGPCS (1901 mL/ minute +/- 1818 to 1662 mL/minute +/- 1035, p = n.s.). CONCLUSIONS: Both TIPS and HGPCS achieved significant reductions in portal vein pressure gradients. Portal flow increased after TIPS, although most portal flow was diverted through the shunt. Effective hepatic flow is reduced significantly after TIPS but well preserved after HGPCS. Hepatic decompensation and mortality after TIPS may be because, at least in part, of reductions in nutrient hepatic flow.

A prospective trial of transjugular intrahepatic portasystemic stent shunts versus small-diameter prosthetic H-graft portacaval shunts in the treatment of bleeding varices.

OBJECTIVE: The authors compare transjugular intrahepatic portasystemic stent shunts (TIPS) to small-diameter prosthetic H-graft portacaval shunts (HGPCS). SUMMARY BACKGROUND DATA: Transjugular intrahepatic portasystemic stent shunts have been embraced as a first-line therapy in the treatment of bleeding varices due to portal hypertension, although they have not been compared to operatively placed shunts in a prospective trial. METHODS: In 1993, the authors began a prospective, randomized trial to compare TIPS with HGPCSs. All patients had bleeding varices and had failed nonoperative management. Shunting was undertaken as definitive therapy in all. Failure of shunting was defined as an inability to accomplish shunting despite repeated attempts, unexpected liver failure leading to transplantation, irreversible shunt occlusion, major variceal rehemorrhage, or death. Mortality and failure rates were analyzed at 30 days (early) and after 30 days (late) using Fischer's exact test. RESULTS: There were 35 patients in each group, with no difference in age, gender, Child's class, etiology of cirrhosis, urgency of shunting, or incidence of ascites or encephalopathy between groups. In two patients, TIPS could not be placed despite repeated attempts. Transjugular intrahepatic portasystemic stent shunts reduced portal pressures from 32 +/- 7.5 mmHg (standard deviation) to 25 +/- 7.5 mmHg (p < 0.01), whereas HGPCS reduced them from 30 +/- 4.6 mmHg to 19 +/- 5.3 mmHg (p < 0.01; paired Student's test). Irreversible occlusion occurred in three patients after placement of TIPS. Total failure rate after TIPS placement was 57%; after HGPCS placement, it was 26% (p < 0.02). CONCLUSIONS: Both TIPS and HGPCS reduced portal pressure. Placement of TIPS resulted in more deaths, more rebleeding, and more than twice the treatment failures. Mortality and failure rates promote the application of HGPCS over TIPS.

Surgical and endovascular intervention for infrainguinal vein graft stenosis.

PURPOSE: The purpose of this study was to evaluate the stenosis-free patency of open repair (vein-patch angioplasty, interposition, jump grafting) and percutaneous transluminal balloon angioplasty (PTA) of 144 vein graft stenoses that were detected during duplex scan surveillance after infrainguinal vein bypass grafting. METHODS: Patients who underwent revision of an infrainguinal vein bypass graft were analyzed for type of vein conduit, vascular laboratory findings leading to revision, repair techniques, assisted graft patency rate, procedure mortality rate, and restenosis of the repair site. RESULTS: The time of postoperative revision ranged from 1 day to 133 months (mean, 13 months). One hundred eighteen primary and 26 recurrent stenoses (peak systolic velocity, >300 cm/s) in 52 tibial and 35 popliteal vein bypass grafts were identified by means of duplex scanning. The repairs consisted of 77 open procedures (vein-patch angioplasty, 28; vein interposition, 33; jump graft, 9; primary repair, 3) and 67 PTAs. No patient died as a result of intervention. Cumulative assisted graft patency rate (life-table analysis) was 91% at 1 year and 80% at 3 years. At 2 years, cumulative assisted graft patency rate was comparable for saphenous vein grafts (reversed, 94%; in situ, 88%; nonreversed, 63%) and alternative vein grafts (89%). Stenosis-free patency rate at 2 years was identical (P =.55) for surgical intervention (63%) and endovascular intervention (63%) but varied with type of surgical revision (P =.04) and time of intervention (<4 months, 45%; >4 months, 71%; P =.006). The use of duplex scan-monitored PTA to treat focal stenoses (<2 cm) and late-appearing stenoses (>3 months) was associated with a stenosis-free patency rate that was 89% at 1 year. After intervention, the alternative vein bypass grafts necessitated twice the reinterventions per month of graft survival (P =.01). Bypass graft to the popliteal versus infrageniculate arteries, site of graft stenosis (vein conduit, anastomotic region), and repair of a primary versus a recurrent stenosis did not influence the outcome after intervention. CONCLUSION: The revision of duplex scan-detected vein graft stenosis with surgical or endovascular techniques was associated with an excellent patency rate, including when intervention on alternative vein conduits or treatment of restenosis was necessary. When PTA was selected on the basis of clinical and duplex scan selection criteria, the endovascular treatment of focal vein graft stenosis was effective, durable, and comparable with the surgical revision of more extensive lesions.