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Biomedical subjects

M A Bettmann

Publications and source records attributed to M A Bettmann.

At least 37 records · Page 2Linked to original sources
PubMed1999

Identification of the portal vein: wedge hepatic venography with CO2 or iodinated contrast medium.

RATIONALE AND OBJECTIVES: The purpose of this study was to evaluate the utility of CO2 versus iodinated contrast medium for wedge hepatic venography in identifying portal vein anatomy during transjugular intrahepatic portosystemic shunt (TIPS) procedures. MATERIALS AND METHODS: Wedge hepatic venograms obtained with CO2 or iodinated contrast medium and direct portograms of 43 patients undergoing TIPS procedures were analyzed retrospectively. Wedge venography was performed in 23 patients with CO2 and in 21 with iodinated contrast medium; direct portography was subsequently performed in 42 of 44 patients with iodinated contrast medium and in one with CO2. All cases were reviewed systematically to compare portal vein anatomy and completeness of anatomic identification between direct portography and wedge venography, and the results with CO2 were compared to those with iodinated contrast material. RESULTS: On the basis of opacification of the main portal trunk, branches, or both, the portal vein appearance (definition of the portal bifurcation) was good to excellent in 21 of 23 patients imaged with CO2 but in only two of 20 patients imaged with iodinated contrast medium. Wedge venograms agreed with direct portograms in 91% (21 of 23) of the CO2 cases and in 10% (two of 20) of the iodinated contrast medium cases. The two patients with poor opacification using CO2 had poor delineation of the main portal trunk, branches, and varices. TIPS could not be created in three patients, In two, abnormal morphology was identified at CO2 venography; in the third, wedge venography was not performed. CONCLUSION: Wedge hepatic venography with CO2 compared with iodinated contrast medium has a substantially higher likelihood of correctly and completely identifying the location and anatomy of the portal vein.

Adult↗
PubMed1999

Outcome and cost comparison of percutaneous transluminal renal angioplasty, renal arterial stent placement, and renal arterial bypass grafting.

PURPOSE: To compare the outcomes and costs of percutaneous transluminal renal angioplasty (PTRA), percutaneous transluminal stent placement (PTSP) of renal arteries, and renal arterial bypass grafting (RABG) in treatment of renovascular hypertension. MATERIALS AND METHODS: Medical records and angiograms of 130 patients who underwent PTRA, PTSP, or RABG were retrospectively studied to determine success and complication rates, angiographic stenoses, blood pressures, antihypertensive medications, and serum creatinine levels. Actual costs were analyzed in detail. RESULTS: Technical success rates for PTRA, PTSP, and RABG were 91%, 98%, and 92%, respectively. Complication rates were 13%, 16%, and 38%, respectively. The mean arterial pressure was initially lowered by 29.2 mm Hg, 30.3 mm Hg, and 27.3 mm Hg, respectively, and maintained at 21.0 mm Hg, 19.8 mm Hg, and 20.2 mm Hg below baseline at 12 months. The number of antihypertensive medications was initially reduced on average by 0.63, 0.72, and 0.58, respectively, but returned to baseline in all patients by 12 months. The serum creatinine level did not change substantially with any treatment. Initial treatment costs were $1,402, $2,573, and $15,393, respectively. CONCLUSION: PTRA, PTSP, and RABG were equally efficacious for control of renovascular hypertension. The initial treatment cost for bypass grafting was substantially higher than that for PTRA and PTSP of renal arteries.

Aged↗
PubMed1998

Transjugular intrahepatic portosystemic shunt in a porcine model: histologic characteristics at the early stage.

RATIONALE AND OBJECTIVES: The authors attempted to determine the histologic processes that take place during development of stenosis after transjugular intrahepatic portosystemic shunt (TIPS) creation. MATERIALS AND METHODS: TIPS were created with metallic stents in 20 healthy domestic pigs (tantalum stents in 10, stainless steel stents in 10). The animals were sacrificed 2-16 days later. All the shunts were examined by means of venography both immediately after placement of the stents and before sacrifice. All histologic sections were assessed with modified Giemsa and basic fuchsin stains. Anti-smooth-muscle-cell alpha-actin stain was used in three specimens. The stenotic reaction was quantified by using standard planimetry techniques and a computerized image-analysis system. RESULTS: Within 16 days after TIPS placement, 15 (75%) of the 20 shunts were completely occluded, four (20%) of 20 shunts were partially occluded, and one (5%) of 20 shunts remained widely patent (animal died of unknown cause 2 days after the TIPS procedure). Stent occlusion was caused primarily by pseudointimal hyperplasia, which was similar morphologically in the portal, middle, and hepatic portions of the stent. Myofibroblastic proliferation was the most striking feature of the pseudointimal hyperplasia. The average thickness of the proliferation was 2.14 mm, which was 67% of the total diameter of the stent. A mild fibrous or lymphocytic reaction occurred around the stent wires and between the pseudointimal hyperplasia and the liver parenchyma. CONCLUSION: The histologic features of pseudointimal formation in this swine TIPS model closely resemble those in humans. This model may prove useful for evaluating stents and other devices and improving the understanding of restenosis after vascular interventions.

Animals↗
PubMed1998

Transjugular intrahepatic portosystemic shunt: effect of bile leak on smooth muscle cell proliferation.

PURPOSE: To evaluate the effect of bile on smooth muscle cell (SMC) proliferation in vitro and in vivo in a porcine transjugular intrahepatic portosystemic shunt (TIPS) model. MATERIALS AND METHODS: In vitro, SMCs explanted from porcine thoracic aorta were cultured with standard techniques. After initial pilot studies, they were subcultured in one of three groups: 1% porcine serum plus 1% bile, 10% porcine serum plus 1% bile, and 10% porcine serum. Cells were harvested at 3, 10, or 14 days, and DNA, protein, and disintegrations per minute (an indicator of proliferation) were measured. In vivo, TIPS creation was successful in 45 swine. All pigs were euthanized at 10-16 days. The proliferative response within the stent was histologically quantified and correlated for evidence of bile leak. RESULTS: In pilot studies, 2.5%-10.0% bile solutions caused 100% SMC mortality by 3 days. In the presence of 1% bile (with or without porcine serum), both DNA and protein production decreased significantly compared with that in porcine serum alone (P < .05). In vivo, 13 of 45 specimens (29%) showed bile leak at gross or microscopic examination. SMC proliferation was less overall in animals with versus those without bile leak (difference not significant). CONCLUSION: These data suggest that the proliferative response in a TIPS is not primarily due to bile leak. Bile leak may promote thrombosis, but it appears to inhibit myointimal proliferation.

Animals↗
PubMed1997

Thrombolysis of occluded infrainguinal vein grafts: predictors of outcome.

PURPOSE: The purpose of this study was to identify factors that influence graft patency and limb salvage rates after thrombolysis of occluded infrainguinal vein grafts. METHODS: The records of patients who underwent percutaneous catheter-directed thrombolysis of occluded infrainguinal vein bypass grafts at our institution between 1985 and 1995 were reviewed. Life table analysis was used to determine survival and patency differences. Univariate and multivariate analyses were used to identify the patient-specific factors that affected outcomes. RESULTS: Forty-four patients with 44 thrombosed infrainguinal vein grafts underwent thrombolysis with urokinase. The thrombolysis-related mortality rate was 2%, and nonfatal complications occurred in 16%. Thrombolysis was unable to restore graft patency in 25% of grafts (11 of 44). Of the remaining 33 successfully lysed grafts, 88% required adjunctive surgery or percutaneous transluminal angioplasty after thrombolysis. Overall, the primary graft patency rate was 25% at 1 year and 19% at 2 years after thrombolysis. Considering only successfully lysed grafts, the primary patency rate improved to 34% at 1 year and 25% at 2 years. Multivariate analysis revealed that the graft patency rate was substantially better in patients without diabetes and in vein grafts that had been in place for longer than 12 months (p < 0.01). The limb salvage rate was significantly improved by successful thrombolysis (63% at 2 years vs 31% if lysis failed; p < 0.01). The patient survival rate was high-89% 2 years after thrombolysis. CONCLUSIONS: Even with adjunctive therapy, vein graft thrombolysis is unlikely to yield durable patency overall. However, successful thrombolysis improves limb salvage rates and may be beneficial in patients without diabetes who have mature vein grafts but who do not have options for other autogenous revascularization procedures.

Aged↗