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Biomedical subjects

J C Palmaz

Publications and source records attributed to J C Palmaz.

At least 19 recordsLinked to original sources
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

[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↗
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↗
PubMed1991

Transfemoral intraluminal graft implantation for abdominal aortic aneurysms.

This study reports on animal experimentation and initial clinical trials exploring the feasibility of exclusion of an abdominal aortic aneurysm by placement of an intraluminal, stent-anchored, Dacron prosthetic graft using retrograde cannulation of the common femoral artery under local or regional anesthesia. Experiments showed that when a balloon-expandable stent was sutured to the partially overlapping ends of a tubular, knitted Dacron graft, friction seals were created which fixed the ends of the graft to the vessel wall. This excludes the aneurysm from circulation and allows normal flow through the graft lumen. Initial treatment in five patients with serious co-morbidities is described. Each patient had an individually tailored balloon diameter and diameter and length of their Dacron graft. Standard stents were used and the diameter of the stent-graft was determined by sonography, computed tomography, and arteriography. In three of them a cephalic stent was used without a distal stent. In two other patients both ends of the Dacron tubular stent were attached to stents using a one-third stent overlap. In these latter two, once the proximal neck of the aneurysm was reached, the sheath was withdrawn and the cephalic balloon inflated with a saline/contrast solution. The catheter was gently removed caudally towards the arterial entry site in the groin to keep tension on the graft, and the second balloon inflated so as to deploy the second stent. Four of the five patients had heparin reversal at the end of the procedure. We are encouraged by this early experience, but believe that further developments and more clinical trials are needed before this technique becomes widely used.

Aged↗
PubMed1991

Aortic bifurcation stenosis: treatment with intravascular stents.

Balloon-expandable intravascular stents were employed to correct atherosclerotic stenosis of the aortic bifurcation. The devices were placed in the proximal iliac arteries with the cephalic end of the stents contacting in the midline. This arrangement provided an adequate lumen for the distal portion of the aortic wall and the proximal iliac arteries. Six of seven patients who received this form of treatment had hemodynamic and clinical improvement of their vascular insufficiency at an average follow-up of 1 year.

Angioplasty, Balloon↗
PubMed1991

[Balloon-expandable stents in arterial changes of the iliac arteries. Early and follow-up results of 65 interventions].

69 balloon-expandable vascular endoprostheses (Palmaz stents) were placed in 65 iliac arteries of 57 patients. The indications for stent placement were total occlusions (n = 15), restenosis after PTA (n = 13), dissections (n = 4), post-operative strictures (n = 3) or others (n = 30). The peak systolic pressure gradient dropped from 43.9 to 2.9, the mean pressure gradient to 1.9 mmHg after stent placement. This was significantly lower than conventional PTA (residual peak systolic pressure gradient: 5.8). Complications occurred in 7.7% of all interventions. 78.4% of the patients showed no limiting claudication after stent placement. Angiographic controls after 47 weeks demonstrated an average intima proliferation of 0.4 mm, not leading to significant restenosis. Cumulative patency after 16 months was 96%. Iliac stents became an effective and in certain situations indispensable adjuvant to PTA.

Adult↗
PubMed1991

Palmaz stent in atherosclerotic stenoses involving the ostia of the renal arteries: preliminary report of a multicenter study.

Palmaz balloon-expandable stents were placed in 28 hypertensive patients with atherosclerosis involving the ostia of the renal arteries. Stents were placed to treat elastic recoil immediately after conventional angioplasty in 20 patients and restenosis after percutaneous transluminal angioplasty in eight patients. Technical success (greater than 30% residual stenosis) was achieved in 27 patients. Complications occurred in five patients. At follow-up (1-25 months), hypertension was cured in three patients and improved in 15 patients, with a cumulative cure or improvement of 64% at 6 months. Of 14 patients with a serum creatinine level of 1.5 mg/dL (132.6 mumol/L) or greater before the placement of stents, five demonstrated improved renal function, five showed stabilization of their condition, and four demonstrated deterioration. Follow-up angiography (2-18 months) was performed in 18 patients. Restenosis was present in seven patients and was accompanied by a relapse of hypertension in only three patients. Of the other four patients with restenosis, two had no initial improvement and two had an initial response without a relapse of hypertension. In this preliminary study, renal stents were beneficial in many patients with poor results from conventional angioplasty for ostial atheroma.

Aged↗
PubMed1991

In vivo technetium-99m S12 antibody imaging of platelet alpha-granules in rabbit endothelial neointimal proliferation after angioplasty.

To examine the specificity of technetium-99m monoclonal antibody (S12) imaging for identifying activated platelets at interventional injury sites in atherosclerotic rabbit arteries, subgroups of unheparinized rabbits (n = 39) underwent serial percutaneous transluminal aortic angioplasty (PTA) procedures (with or without intravascular stent placement) followed by in vivo and then ex vivo gamma camera imaging, scanning, and immunoelectron microscopy to determine the intravascular loci of S12 Fab' antibody binding. Despite angiographic vessel patency, image-derived ratios of in vivo S12 binding in injured versus uninjured vascular segments were significantly increased (p less than 0.05) after one PTA (1.3 +/- 0.17, n = 7), PTA twice at 6-week intervals (1.4 +/- 0.22, n = 7), and PTA plus stent placement (1.6 +/- 0.28, n = 7) compared with control experiments (1.1 +/- 0.13, n = 7). Ex vivo imaging of blood-free excised aortas confirmed S12 localization at PTA (2 +/- 0.4, n = 3) and PTA plus stent placement (5 +/- 3.8, n = 7) sites (both p less than 0.05 versus controls). S12 antibody uptake decreased significantly (p less than 0.05) at 1 week after PTA plus stent placement in vivo (1.1 +/- 0.10, n = 4) and ex vivo (1.6 +/- 0.7, n = 3). Electron microscopic studies confirmed dense platelet, fibrin, and red blood cell deposition in regions of acute injury, with endothelial neointimal proliferation at 1 week after PTA. Immunoelectron microscopic studies confirmed specific in vivo S12 binding (22:1 versus nonrelevant IgG) at sites of alpha-granule GMP-140 expression in activated platelets. Therefore, S12 studies may be useful to localize sites of platelet-derived mitogen release at arterial PTA injury sites.

Angioplasty, Balloon↗
PubMed1991

[Modelling the transjugular intrahepatic portosystemic shunt using a metal prosthesis: requirements of the stent].

Non-operative percutaneous treatment of portal hypertension as ultima ratio therapy in liver cirrhosis has now been established in 16 cases. After transjugular puncture of a main branch of the portal vein via a liver vein, recollapse of the parenchymal track after predilation was prevented by implantation of a Palmaz stent. This type of stent enables remodelling of the individual length of the parenchymal track in the liver by overlapping placement of several stents. In our experience the Palmaz stent seems to be very efficient in keeping the shunt patent. First, its smooth inner surface after dilation guarantees laminar flow within the stent as a precondition for homogeneous endothelialization of the inner surface. Second, overlapping placement of the stents allows precise covering of the individual length of the shunt. Third shunt diameters can be established by using different sized balloons. The range is 7-10 mm. Fourth this type of stent has a high degree of resistance to eccentric or concentric compression by the surrounding tissue.

Adult↗
PubMed1991

[Generalized arteriosclerosis and stent implantation. An epicritic report].

In a comprehensive demonstration we report on the long-term course of the first patient in the world to receive a vascular balloon expandable endoprosthesis (Palmaz iliac vascular stent). Iliac occlusive disease became apparent again several years after an initially successful regular balloon angioplasty of the left common iliac artery. After successful stent implantation the patient then remained completely asymptomatic over unlimited walking distance during the follow-up of 29 months, after which he died of a myocardial reinfarction. While repeat catheter angiography showed excellent incorporation of the metal stent, arteriosclerotic disease was found to have progressed in the distal abdominal aorta. Thus, the patient died of a typical complication of peripheral vascular disease, naturally reflecting the generalized character which cannot be affected by local treatment modalities. While microscopic evaluation revealed "ideal" biocompatibility of the device, portraying its high functional efficacy, the natural course of the patient reflects the purely symptomatic character of the improvement. An interesting finding was the homogeneous architecture of the neointima that developed on top of the stent. While large parts of the adjacent vessel wall had undergone significant arteriosclerotic changes this was not found in the neointima, which was made up exclusively of mature fibrocollagenous tissue.

Aged↗
PubMed1990

[Animal experimental studies on the effect of flow restriction on the thrombogenicity of the Palmaz stent using 111Indium-marked thrombocytes].

The purpose of this experimental study in dogs is to evaluate the influence of restricted flow on the thrombogenicity of balloon-expandable intravascular stents (Palmaz type). We implanted 24 Palmaz stents in the femoral artery of mongrel dogs. 12 dogs experienced a 75% flow restriction by means of an artificial stenosis distal to the start in the outflow tract. We used 111In labelled thrombocytes as a marker for thrombus detection within the stent. The results presented demonstrate that there is no considerable risk of thrombus formation if the stent is implanted into vessels with good outflow tracts and therefore high blood flow velocities within the stent. Under conditions of highly impaired flow, a 68% rate of stent occlusion occur if no anticoagulation therapy is performed. After i.v. administration of 100 IU/kg body weight of heparin the occlusion rate drops to zero. It can be concluded that even under low-flow conditions as a result of a restricted outflow tract situation the Palmaz stent can be implanted without any risk of stent occlusion as long as a sufficient anticoagulation protocol is maintained.

Animals↗
PubMed1990

Transjugular intrahepatic portacaval stent shunt: preliminary clinical results.

A percutaneous transjugular, intrahepatic portacaval shunt was created by means of a combined jugular and transhepatic approach. In the hepatic tissue track joining the portal and hepatic veins balloon-expandable stents were placed. Two of three patients with life-threatening variceal bleeding and Child C liver cirrhosis benefited from the procedure. One patient in severe hepatorenal failure prior to the procedure died 11 days after the shunt procedure of pulmonary complications. This procedure may be a promising alternative to current therapy in high-risk patients with esophageal bleeding.

Adult↗