PubMed Health⌕ Search

Biomedical subjects

J C Palmaz

Publications and source records attributed to J C Palmaz.

At least 19 recordsLinked to original sources
PubMed1997

Transjugular intrahepatic portosystemic shunts: assessment with helical CT angiography.

To evaluate diagnostic computed tomographic (CT) angiograms of transjugular intrahepatic portosystemic shunts (TIPS), helical CT angiography was performed in 10 patients with (n = 7) or without (n = 3) shunt dysfunction. CT angiography was performed with 3-mm-thick sections, pitch of 1, 120 kV, and 180-220 mA, after injection of 150 mL nonionic contrast material at 5 mL/sec, with a 50-second scanning delay after initiation of injection. All patients underwent transjugular portography within 1 week after CT angiography. In all cases, CT angiography correctly showed the presence or absence of the abnormality. These preliminary data suggest that CT angiography can provide diagnostic images of normal and abnormal TIPS.

Adult↗
PubMed1997

New advances in endovascular technology.

Future research on and development of intravascular stents, stent grafts, and other implantable devices will be aimed largely at improving their blood and tissue biocompatibility. Most of the modifications resulting from this research and development will alter the surface properties we currently understand: surface energy or "wetability," electrical surface charge, surface texture, and surface chemistry. However, as knowledge of the physical, chemical, and biological properties of bioprosthetic surface materials expands, new areas for exploration will develop, increasing the opportunities for improvement.

Angioplasty, Balloon, Coronary↗
PubMed1996

Aortoiliac aneurysms: management with endovascular stent-graft placement.

PURPOSE: To evaluate endovascular stent-graft placement for management of aortoiliac aneurysms. MATERIALS AND METHODS: Balloon-expandable stents covered with polytetrafluoroethylene were placed in 11 aortoiliac lesions in nine male non-surgical candidates (mean age, 63.5 years). There were six abdominal aortic aneurysms, four iliac artery aneurysms, and one acute pseudoaneurysm from a ruptured iliac artery. Stent-grafts were dilated up to 14 mm (iliac) and 24 mm (aorta). Patients underwent follow-up computed tomography and angiography. RESULTS: Stent-grafts were successfully placed in all 11 cases. There were two complications: a ruptured iliac artery treated with placement of an additional covered stent and a lower-extremity vessel embolization and bowel infarction resulting in death. All stent-grafts remained patent without increased aneurysmal diameter. Three leaks (27%) were detected. Two leaks were treated with placement of additional covered stents. One still is asymptomatic. CONCLUSION: Endovascular treatment of aortoiliac aneurysms with stent-graft devices may be an alternative to surgery.

Aged↗
PubMed1996

Improvement of thrombocytopenia due to hypersplenism after transjugular intrahepatic portosystemic shunt placement in cirrhotic patients.

Thrombocytopenia secondary to hypersplenism is a well-known complication of portal hypertension. The effects of transjugular intrahepatic portosystemic shunt (TIPS) on hypersplenism have not been adequately studied. In this report, we describe 11 patients who had significant improvement in their thrombocytopenia due to hypersplenism after TIPS. There was a statistically significant improvement in the platelet counts after TIPS placement, in virtually every case during the follow-up period, although some patients had platelet counts less than 100,000/mm3 at the end of the follow-up period. Statistically significant hemodynamic improvement in the gradient pressure was observed immediately after TIPS. Furthermore, all patients tolerated the procedure well, and TIPS-related complications were encountered during the follow-up period. Our data suggest that TIPS is an effective, noninvasive alternative to surgical interventions in the management of hypersplenism in cirrhotic patients, who are generally high-risk surgical candidates.

Adult↗
PubMed1995

Dissection of the external iliac artery in highly trained athletes.

We report a series of four acute external iliac artery dissections occurring in three patients within days of completion of ultraendurance athletic events. Acute dissection of the external iliac artery in highly trained athletes after competition has not been previously documented. A retrospective review of three cases was performed with subsequent follow-up, including imaging and hemodynamic measurements. Dissection was suspected on the basis of duplex imaging results in one case, and arteriography confirmed dissection in all cases. All patients were endurance athletes over the age of 40 years. One patient was found to have bilateral lesions. Treatment in two cases was initiated with percutaneous transluminal angioplasty, one with a successful result and subsequent Plamaz stent placement. In the other case percutaneous transluminal angioplasty was unsuccessful, and operative repair was required with the placement of a graft. The final patient who had bilateral involvement was treated conservatively. At a mean follow-up of 32 months, there have been no complications, and all patients have normal resting hemodynamics. Follow-up duplex imaging shows healing of the dissections in the untreated patient. Histopathologic study in the patient treated with operation disclosed dissection in an otherwise normal arterial wall. Highly trained athletes over the age of 40 are susceptible to external iliac artery dissection, and successful treatment has been achieved by surgical, endovascular, and conservative therapies.

Acute Disease↗
PubMed1995

Percutaneous aortic stent placement for life threatening aortic rupture due to metastatic germ cell tumor.

Patients with testicular carcinoma frequently present with advanced disease and symptoms resulting from metastatic lesions. We report an unusual case of successful emergency management of a massive rupturing aortic pseudoaneurysm midway through systemic chemotherapy for stage III germ cell tumor by percutaneous trans-luminal placement of an aortic bypass stent-graft. Unstable hemorrhage was controlled, allowing our patient to complete chemotherapy and undergo elective retroperitoneal lymph node dissection with resection of the pseudoaneurysm and residual disease after normalization of tumor markers. Final pathological evaluation revealed only fibrosis in the resected tissue. Followup angiography demonstrated a patent stent-graft and the patient was without evidence of disease 1 year after retroperitoneal lymph node dissection.

Adult↗
PubMed1994

Vascular occlusion with a balloon-expandable stent occluder.

PURPOSE: To evaluate the effectiveness of a new vascular occlusion device. MATERIALS AND METHODS: The device was created by coating a balloon-expandable stent with a silicone sleeve that tapers to a blind-ended nozzle at its leading end. Once crimp-mounted on an angioplasty balloon catheter, the device is introduced over a guide wire through a small end hole in the nozzle. RESULTS: The device was tested for stability and occlusive ability. No migration was measured over a pulsatile pulse range of 50-300 mm Hg, and mean flow rate in the occluded vessel was reduced from 443 mL/min +/- 99 (standard deviation) to 1.9 mL/min +/- 2.7. Subsequently, 12 arteries were occluded in three dogs, and immediate vascular occlusion was achieved in all vessels. An arteriovenous fistula was created in another six dogs and was successfully occluded with the device. Follow-up arteriography at 3 months demonstrated persistent occlusion with no migration of the device. CONCLUSION: This new occlusive device offers immediate vascular occlusion with excellent stability.

Angioplasty, Balloon↗
PubMed1994

[Transluminal stent prosthesis in aneurysm of the abdominal aorta. Initial experiences with a new procedure].

We report our initial experience with percutaneous treatment of aortic aneurysms in three patients by stent grafts. A newly developed balloon-expandable Palmaz stent in combination with predilated PTFE was used. In two patients a tube-type reconstruction was performed and in the third patient an aorto-bi-iliac reconstruction. Total exclusion of the aneurysm was achieved in one patient. The other two patients had an acceptably minimal amount of residual perfusion, which slightly decreased during the follow-up period of 6 months. One iliac rupture occurred that was immediately treated by insertion of another stent graft. This study confirms the feasibility of such a concept. Further investigation is warranted.

Aged↗
PubMed1994

[Historical and conceptional aspects of TIPSS].

The concept of a percutaneous approach to portosystemic shunting to treat variceal bleeding from portal hypertension dates back to the 60s. However, the clinical realization of this idea was based on the development of metallic endoprotheses (stents), which were essential for long-term patency of a parenchymal tract between the portal circulation and (systemic) hepatic veins that was created by a percutaneous transjugular approach (TIPSS: transjugular intrahepatic portosystemic stent shunt). The first clinical success of TIPSS was achieved in 1988 at the University of Freiburg, Germany. Since then, however, the concept and methodology of TIPSS have been constantly refined, so that this method has become a standard procedure for the interventional radiologist.

Catheterization↗
PubMed1993

Re-expansion of balloon-expandable stents after growth.

OBJECTIVES: The purpose of this study was to evaluate the feasibility of re-expansion of balloon expandable intravascular stents and to examine the gross and histologic effects of re-expansion on vascular integrity. BACKGROUND: Intravascular stents have been used successfully as an adjunct to balloon dilation of congenital pulmonary artery branch stenosis and postoperative stenosis of the pulmonary arteries in children. However, use of rigid stents in children could result in development of relative stenosis at the site of stent implantation with subsequent growth of the child. METHODS: Stainless steel "iliac" stents were placed in the thoracic aorta of 10 normal juvenile swine by a transcatheter technique. Angiography and re-expansion were performed at a mean of 11 weeks (n = 9) and again at 18 weeks (n = 5). After euthanasia, the aortic specimens were removed for gross and histologic examination. RESULTS: Stents were successfully implanted in 10 swine. Re-expansion was successfully performed in each animal at 11 weeks and at 18 weeks. Aortic growth produced a relative constriction of the aorta of 20% +/- 10% (mean +/- SD) at the site of stent implantation at both 11 and 18 weeks. Re-expansion produced a significant increase in mean stent diameter from 10.1 +/- 1 mm to 12.3 +/- 1.2 mm at 11 weeks and from 11.2 +/- 0.7 to 13.5 +/- 1.1 mm at 18 weeks after implantation (p < 0.001). Balloon dilation produced a relative increase in stent diameter of 21% +/- 7% at 11 weeks and 18% +/- 4% at 18 weeks. Stent re-expansion was accompanied by plastic deformation of the neointima without neointimal dissection. Where neointima was thick, there was no evidence of neointimal abrasion, but where neointima was thin, areas of localized neointimal abrasion were observed with focal fibrin and platelet adherence to the stent struts. There was no evidence of medial or adventitial hemorrhage or dissection produced by re-expansion. CONCLUSIONS: Re-expansion of intravascular stents is feasible after growth in juvenile swine without significant injury to neointima, media or adventitia. The results of this study support careful and selective use of intravascular stents as an adjunct to balloon dilation of congenital stenoses in children.

Animals↗
PubMed1992

Intraluminal bypass of abdominal aortic aneurysm: feasibility study.

This study evaluated the feasibility of treatment of abdominal aortic aneurysm (AAA) by means of intraluminal bypass. Artificial aortic aneurysms with fusiform Dacron conduits were created at surgery , a weft-knit Dacron tube with balloon-expandable stents attached at both ends was inserted transfemorally through a 14-F introducer sheath and expanded at the aneurysmal level by means of inflation of a coaxial balloon. The transluminal bypass successfully excluded the aneurysmal lumen immediately after placement. In two dogs, a postplacement aortogram revealed torsion of the graft that caused early occlusion. The six other dogs had a patent bypass at 6 months follow-up. Four of these dogs had evidence of kinking of the graft as a result of shrinkage of the prosthetic aneurysm. Histopathologic studies revealed that endothelialization was complete on the stents and partial on the graft surface. It is concluded that transluminal bypass of AAA is feasible in the dog model.

Animals↗
PubMed1992

Imaging of vascular injury with 99mTc-labeled monoclonal antiplatelet antibody S12. Preliminary experience in human percutaneous transluminal angioplasty.

BACKGROUND: To evaluate the in vivo safety, biodistribution, and diagnostic accuracy of a monoclonal Fab' antibody (S12) that is specific for the platelet membrane glycoprotein (GMP-140) expressed during platelet activation at vascular injury sites, 11 peripheral percutaneous transluminal angioplasty (PTA) patients (age, 61 +/- 8 years) with severe vascular disease had serial 99mTcS12 radionuclide imaging at 5 and 90 minutes, 4-6 hours, and 20-24 hours after a total of 23 angiographically successful PTA procedures. No acute allergic reactions or hematologic toxicity occurred. METHODS AND RESULTS: The average PTA percent angiographic diameter stenosis (DS) at all 23 sites decreased from 85 +/- 12% to 12 +/- 11%, with a mean before-to-after-PTA change of 73 +/- 14% (p less than 0.01). The mean radionuclide image-derived ratio of 99mTc S12 activity in PTA versus contralateral non-PTA arterial segments for all angioplasty sites was 1.6 +/- 0.5. Vascular 99mTc S12 antibody activity was qualitatively evident in the majority (78%) of PTA sites at 4-6 hours after injection. 99mTc S12 target-to-background (muscle) ratio equaled 2.3 +/- 0.6 at PTA sites. Nine PTA sites (39%) had residual 99mTc S12 activity at 24 hours after injection (mean PTA site-to-contralateral artery ratio, 1.5 +/- 0.4). The mean vascular 99mTc S12 activity ratios in 10 procedurally complicated (defined as extensive dilation [greater than 2 cm] or grade I or greater arterial dissection) and 13 uncomplicated PTA segments were 1.9 +/- 0.5 versus 1.2 +/- 0.1, respectively (p less than 0.01). The associated before-to-after-PTA angiographic improvement was significantly less in procedurally complicated PTA sites (66 +/- 12% versus 80 +/- 12% DS; p less than 0.01). CONCLUSIONS: 99mTc S12 activity is significantly increased at angiographically patent PTA sites that are procedurally complicated and are associated with less significant before-to-after-PTA angiographic improvement. 99mTc S12 monoclonal Fab' antibody imaging permits noninvasive identification of local vascular platelet activation resulting from angioplasty balloon injury in humans.

Angioplasty, Balloon↗
PubMed1992

Variceal hemorrhage associated with portal vein thrombosis: treatment with a unique portal venous stent.

A patient with an uncommon cause of portal venous hypertension, pancreatitis, is depicted. The patient had an equally uncommon pattern of symptoms and signs consisting of abdominal pain and lower gastrointestinal hemorrhage caused by colonic varices. A unique treatment, with angiographic placement of an expandable intraluminal stent within the portal vein, was employed to reopen the portal venous system and reduce portal pressure. Relief of bleeding was accomplished and sustained for more than 1 year.

Gastrointestinal Hemorrhage↗