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Biomedical subjects

John A Kaufman

Publications and source records attributed to John A Kaufman.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of the endothelialization of small intestinal submucosa, dacron, and expanded polytetrafluoroethylene suspended in the thoracoabdominal aorta in sheep.

PURPOSE: This study was undertaken to evaluate and compare endothelialization of small intestinal submucosa (SIS), Dacron, and expanded polytetrafluoroethylene (ePTFE) in high-pressure flow without aortic wall contact and to evaluate the suitability of SIS as a vascular graft material. MATERIALS AND METHODS: In 12 adult sheep, three types of membrane leaflets of similar thickness (approximately 200 mum) were suspended within large square stents without contact with the thoracoabdominal aortic wall: SIS (n = 12), Dacron (n = 12), and ePTFE (n = 12). Each animal received one leaflet of each material. Aortograms were obtained before and after percutaneous implantation and when the animal was killed at 8 weeks (n = 6) or 18 weeks (n = 6). Cell coverage and remodeling of SIS, Dacron, and ePTFE membranes were assessed by gross and histologic microscopic examinations. RESULTS: Thirty-five successfully implanted leaflets were evaluated. SIS showed progressive remodeling. Thirty-three leaflets exhibited thickening as a result of neointimal formation and endothelialization, most likely from circulating endothelial cells. Dacron exhibited the greatest and most progressing degree of neointimal formation and endothelialization, followed by SIS and then ePTFE. With SIS and ePTFE, neointimal formation decreased with time, but endothelialization was stable. Uneven neointimal formation and endothelialization on the outer surfaces and distal leaflet positions were seen. CONCLUSIONS: SIS showed progressive remodeling with moderate and regressive neointimal formation and moderate stable endothelialization. Further study of its durability and incorporation into the aortic wall needs to be performed to evaluate its suitability as a cover for aortic endografts.

Animals↗
PubMed2006

Percutaneous treatment of aberrant right subclavian artery aneurysm with use of the Amplatzer septal occluder.

Aberrant right subclavian artery (ARSA) aneurysms are rare but carry a high risk of rupture and require early elective treatment. The present report describes a 60-year-old man with an asymptomatic ARSA aneurysm for whom surgical treatment would have been associated with a high degree of risk. The ARSA aneurysm was occluded with use of Amplatzer septal occluders, which avoided high-risk surgery and preserved antegrade flow into the left common carotid, subclavian, and vertebral arteries and perfusion of the right upper extremity through an induced right subclavian steal. The eventual need for bypass surgery for perfusion of the right upper extremity was assessed after the procedure.

Aneurysm↗
PubMed2006

Günther Tulip filter retrievability multicenter study including CT follow-up: final report.

PURPOSE: To evaluate the safety and effectiveness of retrieval of the Günther Tulip inferior vena cava (IVC) filter. MATERIALS AND METHODS: This was a nonrandomized, single-armed, multicenter prospective investigation. Patients at temporary high risk for pulmonary embolism (PE) or deep vein thrombosis (DVT) who did not require a permanent filter were eligible. Forty-one patients received 42 Günther Tulip filters: 22 men and 19 women with a mean age of 47.7 years. Indications for filter placement included prophylaxis, PE, and DVT. Three months after filter retrieval, contrast agent-enhanced computed tomography of the abdomen, jugular vein ultrasonography, and clinical follow-up were performed. RESULTS: The filter retrieval rate was 57% (23 of 41). Günther Tulip filters were removed at a mean of 11.1 days (range, 2-14 d). The technical and clinical success rates for filter retrieval were both 100%. One placement complication and two protocol deviations occurred. These patients were excluded in terms of retrieval-related outcomes. One case of PE occurred with a filter in place, and one filter migrated to the heart. There were no acute complications caused by filter retrieval. At 3-month follow-up, there was no recurrent PE, DVT, jugular vein occlusion, or IVC stenosis or occlusion. CONCLUSION: In this multicenter study, retrieval of the Günther Tulip filter was safe and without recurrent thromboembolic events or evidence of IVC or jugular vein damage at 3-month follow-up.

Adult↗
PubMed2005

CT and fluoroscopically guided percutaneous embolization treatment of a pseudoaneurysm associated with pancreatitis.

A novel approach to embolization treatment with a cyanoacrylate solution for a bleeding pseudoaneurysm associated with pancreatitis is described in the setting of a critically ill patient. Computed tomography and a C-arm fluoroscopic unit were used to guide percutaneous placement of a needle and injection of the embolic material. This technique represents an alternative form of embolization when traditional angiographic techniques are not possible.

Aneurysm, False↗
PubMed2005

Retrieval of a malpositioned vena cava filter with embolic protection with use of a second filter.

Proper positioning of inferior vena cava (IVC) filters is necessary for effective protection from pulmonary embolism (PE). This report describes a case of an IVC filter malpositioned partially in the right common iliac vein that resulted in risk of recurrent PE caused by thrombus emanating from the left common iliac vein. A new filter was placed in the IVC above the first device, followed by retrieval of the malpositioned filter through the new filter.

Catheterization, Central Venous↗
PubMed2005

Significance of spatial orientation of percutaneously placed bioprosthetic venous valves in an ovine model.

PURPOSE: To investigate two spatial orientations of a percutaneously placed bicuspid second-generation bioprosthetic venous valve (SG-BVV) in the jugular vein (JV). MATERIALS AND METHODS: Twelve SG-BVVs, consisting of small intestinal submucosa attached to a nitinol frame were placed across a natural valve (NV) in the distal JV in six sheep. Six SG-BVVs were oriented as NV leaflets (group A) and the other six SG-BVVs were rotated 90 degrees to NV leaflets (group B). SG-BVV function was studied by venography performed immediately after placement and at 5 weeks after placement. Animals were killed at 5 weeks, and gross examinations were performed. RESULTS: Desired valve orientation after deployment was seen in all SG-BVVs. In group A, all valves exhibited good valve function on immediate and 5-week venography. At gross examination, leaflets were attached mostly at the valve base and free cusp areas were similar in both cusps with a mean of 154.8 mm2 +/- 45.6 for one cusp and 142 mm2 +/- 53.4 for the other cusp (P = .188). In group B, all valves showed good function on immediate venography and in five valves prior to killing. Valve attachment to the vein wall in this group involved a longer segment of leaflets and their free areas were smaller with a wide variety of cusp sizes. Mean free leaflet areas of opposing cusps measured 106.3 mm2 +/- 36.5 and 66.1 mm2 +/- 34.6, respectively (P = .025). Difference in leaflet areas between group A and group B was significant (P = .019). CONCLUSION: Proper spatial orientation of the SG-BVV at deployment is important for valve function and should have the same orientation as the NV.

Animals↗
PubMed2005

Long-term optional retrievability of a new inferior vena cava filter in an ovine model.

Long-term retrievability of a new optional retrieval inferior vena cava (IVC) filter composed of a modified square stent and a modified Günther Tulip filter was tested in eight sheep. Eleven filters were placed into the IVC and eight were successfully retrieved 3-5 months after implantation. Incorporation of the filter struts into the IVC wall prevented its retrieval in three sheep at 3, 4, and 5 months after placement.

Animals↗
PubMed2004

Small intestinal submucosa aneurysm sac embolization for endoleak prevention after abdominal aortic aneurysm endografting: a pilot study in sheep.

PURPOSE: To percutaneously create an improved abdominal aortic aneurysm model of endoleak after endograft placement and to explore efficacy of small intestinal submucosal embolization of the residual aneurysmal sac for prevention of endoleaks. MATERIALS AND METHODS: Abdominal aortic aneurysm was created transluminally by over-dilation of a Palmaz stent in 12 sheep. Approximately 20% undersized endografts suspended between two stent-graft adapters were used to bridge the aneurysm in a manner that two lumbar pairs remained patent within the residual aneurysm sac. Size of the residual aneurysm sac was increased by placement of an undersized stent-graft consisting of damaged lyophilized small intestinal submucosal sheets sandwiched between two Zilver stents. In six sheep, residual aneurysm sacs were embolized by combining small intestinal submucosal sponge and small intestinal submucosal sheet pieces. The other six sheep served as the control group. Angiography performed immediately after the procedure was compared with follow-up angiography before the animals were killed at 1, 3, and 7 months. Gross and histologic examinations were also obtained. RESULTS: Aortic ruptures (n = 3) and dissections (n = 2) during aneurysm creation responded well to endograft placement. Eleven endografts were placed successfully, one was misplaced. The mean diameter of aneurysmal sac was 16 mm in the study and 15.2 mm in the control group. In the study group, in four sheep, the sac and seven pairs of lumbar arteries were occluded by embolization and remained obstructed by organized thrombus during the entire study. There were no type II endoleaks. Four type III new endoleaks developed without antegrade filling of lumbar arteries. In the control group, five animals had type I and II endoleaks at the initial studies. Only one sheep exhibited completely organized thrombosis of the aneurysmal sac and without endoleaks. In the other four sheep with partially organized sac thrombosis, endoleaks were unchanged. One type III endoleak occurred in this group. CONCLUSION: The combination of small intestinal submucosal sponge and small intestinal submucosal sheet pieces is a promising embolic material for occlusion of the residual sac after endovascular abdominal aortic aneurysm repair and for prevention of type II endoleaks.

Animals↗
PubMed2004

Peripheral vascular disease: blinded study of dedicated calf MR angiography versus standard bolus-chase MR angiography and film hard-copy angiography.

PURPOSE: To compare the accuracy of contrast material-enhanced three-dimensional (3D) dedicated calf magnetic resonance (MR) angiography with that of bolus-chase MR angiography, with conventional angiography as the reference standard, in patients with symptomatic peripheral vascular disease (PVD). MATERIALS AND METHODS: Thirty men with symptomatic PVD were examined. MR angiography was performed at 1.5 T before conventional angiography. MR angiographic examination included 3D contrast-enhanced dedicated calf MR angiography and three-station bolus-chase MR angiography. Two radiologists blinded to conventional angiographic results evaluated the MR angiograms independently. Two angiographers evaluated the conventional angiograms in consensus. Calf artery segments were graded as having 50% or less stenosis, greater than 50% stenosis, or occlusion or as being nondiagnostic. Statistical analyses were performed with paired permutation testing. RESULTS: Analyses of 472 calf segments and 420 pelvic and thigh segments were performed. Of the 472 calf segments, three and 75 segments (reader 1) and seven and 91 segments (reader 2) were graded as nondiagnostic at dedicated calf MR angiography and bolus-chase MR angiography, respectively. Differences in diagnostic grade between the two examinations were significant (P <.001), accounting for within-subject correlations, with a mean estimated difference of -17.1% (95% confidence interval [CI]: -25.8%, -8.4%). In the calf arteries, the dedicated and bolus-chase MR angiographic sequences had diagnostic accuracies, respectively, of 81.5% (reader 1) and 79.1% (reader 2) and of 67.8% (reader 1) and 63.4% (reader 2). The dedicated calf sequence was significantly more accurate than the bolus-chase sequence (P =.001). The point estimate of the difference was 14.7%, with estimated correct diagnosis rates of 80.3% and 65.6% for the dedicated calf and bolus-chase examinations, respectively (95% CI for difference: 4.0%, 25.4%). The diagnostic accuracy of bolus-chase MR angiography at the pelvis-thigh level was slightly higher when it was performed first: 81.9% (reader 1) and 83.8% (reader 2) versus 74.3% (reader 1) and 80.0% (reader 2) when it was performed last. The difference was not significant (P =.21). CONCLUSION: Use of dedicated calf MR angiography led to significantly increased diagnostic accuracy in the calf arteries compared with standard bolus-chase MR angiography. Use of the dual-bolus technique did not jeopardize the diagnostic accuracy in the pelvic and thigh arteries.

Aged↗