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Biomedical subjects

G M Richter

Publications and source records attributed to G M Richter.

At least 19 recordsLinked to original sources
PubMed1992

Diagnosis and treatment of retroperitoneal hematoma in multiple trauma patients.

From 1984 to 1991 20 multiple trauma patients with pelvic fractures and retroperitoneal bleeding from pelvic vessels underwent angiographic localization and embolization of massively bleeding arterial vessels. Nine patients survived (multiple trauma index grade III, Hanover polytrauma index), three patients with very severe injuries died immediately (multiple trauma index grade IV). After successful control of bleeding by embolization, three other patients died from severe brain injuries and five patients from septic multiorgan failure. The interval to definite localization and treatment of the bleeding source was three times shorter in the group of survivors, and the amount of transfusions needed was less by a factor of three. This underlines the importance of early angiography in multiple trauma patients with pelvic fractures and persisting hemorrhage. Embolization has proven to be effective in the treatment of such injuries.

Adolescent↗
PubMed1992

[Renal tumor embolization].

We present an update on the technical aspects and clinical efficacy of the concept of capillary embolization for the treatment of renal cell carcinoma. In preoperative indications, it is shown that only this type of occlusion can safely achieve a reliable breakdown of the peritumor vasculature to meet the surgical requirements for excision of huge tumors associated with abundant retroperitoneal tributaries. In particular, in tumors infiltrating the renal vein and the vena cava, capillary embolization proved to be extremely helpful. In palliative embolization the concept achieved local and clinical efficacy comparable to nephrectomy when applied in patients free of metastatic disease. In palliative embolization of patients with metastatic disease, no change in the natural history was found. A new but still experimental concept is the combination of chemoperfusion and chemoembolization for tumor nodules in a solitary kidney and for reoccurring retroperitoneal tumors. The application of a coaxial system that features perfect maneuverability enables tumor treatment on the level of subsegmental vessels. The first short-term results seem to be promising. If definite proof of the validity of such a concept is to be obtained, however, further long-term research needs to be conducted on larger numbers of patients.

Carcinoma, Renal Cell↗
PubMed1992

[Liver transplantation after trans-jugular intrahepatic portosystemic stent shunt].

Every third patient with parenchymal liver disease bleeds from esophageal varices. Treatment of this complication is of special interest with regard to liver transplantation which may become necessary later on. The mesocaval H-shunt excluded, surgical shunting results in technical and hemodynamic problems during transplantation. They may be avoided by the new approach of transjugular intrahepatic portosystemic stent shunt (TIPSS). We report our experience with liver transplantation in two patients after TIPSS.

Adult↗
PubMed1992

[Pulmonary arteriovenous fistulas in Osler's disease].

In a retrospective study over a period of 10 years we found 16 patients with Osler's disease and associated pulmonary arteriovenous fistulas in the hospital of the University of Heidelberg and the Thoraxklinik Heidelberg-Rohrbach. We report about the radiologic diagnostic findings and the clinical manifestations of this defined pulmonary malformation. Radiologic findings are round or oval lobulated homogeneous masses. The size ranges from < 1 to several centimeters in diameter, most fistulas were located in the lower lobes. Feeding and draining vessels can be identified frequently on plain radiographs or tomograms/CT. Best procedure to recognize these malformations is the selective pulmonary arterial angiography.

Adult↗
PubMed1991

[Intra-arterial chemotherapy in locally advanced breast carcinomas].

Transcatheter arterial chemotherapy with mitoxantrone was carried out in 9 patients suffering from advanced breast cancer. The anticancer agent was selectively injected in the internal mammary artery. In 2 cases the catheter was super-selectively advanced into a peripheral branch of the internal mammary artery supplying the breast carcinoma. No complication of the transcatheter treatment could be observed. CT examinations for controlling the catheter position showed perfusion of breast cancers between 40 and 90 per cent. Histological examinations of the 7 resected specimens revealed extensive necrosis in all cases. All 7 patients who underwent surgery have been without local recurrence for 3 to 12 months after treatment.

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

[4 years' experience with a balloon-expandable endoprosthesis. Experimental and clinical application].

During a 4-year period of clinical application of the balloon-expandable Palmaz stent, a randomized trial comparing stent implantation and traditional balloon angioplasty of iliac arteries in arterial occlusive disease was started. The first long-term results, recorded after 2 years, indicate statistically significant differences in the complication rate (after stenting 2/62 and after angioplasty 5/69) and patency (greater than or equal to 70% of original lumen size upon stent implantation or balloon inflation: 95% after stenting and 72% after angioplasty). Clinical improvement after 2 years was 89% after stenting and 70% after angioplasty. Parallel to the clinical trials, experimental canine artery stenting was performed to evaluate differences in the long-term patency of stents exposed to restricted flow. Significant differences in neointimal healing were found between normally perfused stents and stents with artificially reduced flow: during the total observation period of 6 months the neointimal height was up to 200% higher in flow-restricted stents, while the histological composition of the neointima was the same as with normally perfused stents.

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

Massive pelvic osteolysis in the Gorham-Stout syndrome.

Massive osteolysis is a very rare tumour-like lesion usually affecting young adults. There are 132 reported cases which we have reviewed, including 31 single cases of pelvic involvement. The term "massive osteolysis" is based on the typical radiological findings, such as increasing translucency and loss of bone density. The diagnosis of the Gorham-Stout syndrome must be confirmed by the microscopic finding of intramedullary vascular structures. Our patient was a 23 year old white Caucasian, who had the full clinical signs of Gorham-Stout syndrome. She had achieved 2 normal pregnancies and deliveries in spite of her massive pelvic osteolysis.

Adult↗
PubMed1990

[Imaging of the hip joint hyaline cartilage with MR tomography using a gradient echo sequence with fat-water phase coherence].

We have been able to display the hyaline hip joint cartilage clearly and with high signal strength in the magnetic resonance image with a gradient echo sequence with 2 different fresh hip specimens from corpses and with 10 healthy test subjects (5 m, 5 f). The chemical shift artifact at the bone-cartilage boundary could be clearly reduced by optimizing the geometrical scanning parameters. A comparison between the cartilage thickness at the head of the femur measured on the anatomical specimen with the thickness measured in the magnetic resonance tomogram showed a good correlation on suitable selection of the read-out gradient. The hyaline cartilage at the head of the femur could be differentiated from the acetabular cartilage in the region of the loading zone by magnetic resonance tomography in all 10 test subjects.

Cartilage, Articular↗
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↗
PubMed1990

Placement of balloon-expandable intraluminal stents in iliac arteries: first 171 procedures.

Balloon-expandable intraluminal stents were used to treat iliac artery stenoses or occlusions that failed to respond to conventional balloon angioplasty. One hundred seventy-one procedures were performed in 154 patients, of whom 48 had a limb at risk for amputation. Thirty-six had severe and 70 had moderate intermittent claudication. At the latest follow-up examination (average, 6 months; range, 1-24 months), 137 patients demonstrated clinical benefit, 113 of whom had become asymptomatic. Eleven patients showed no initial benefit, and six improved initially but later developed new vascular symptoms. Complications occurred in 18 patients. In three patients, complications were directly related to the device. Two occlusions were successfully recanalized, and an intramural collection of contrast material secondary to balloon perforation evolved favorably. The remaining patients had groin hematoma (n = 6), distal embolization (n = 4), extravasation (n = 2), transient renal failure (n = 1), pseudoaneurysm at the puncture site (n = 1), or subintimal dissection (n = 1). All stents have remained patent to the latest follow-up examination without evidence of migration or aneurysm formation.

Adult↗
PubMed1990

Angioplasty-induced dissections in human iliac arteries: management with Palmaz balloon-expandable intraluminal stents.

Intravascular stent placement may be an effective treatment for percutaneous transluminal angioplasty (PTA)-induced dissection. Among the first 228 patients treated with Palmaz balloon-expandable intraluminal stents (BEISs) for iliac artery stenosis, stents were used to treat PTA-induced dissection in at least 12 iliac arteries in 11 patients. All 12 vessels were shown by angiography to be severely dissected. Stents were placed at the time of PTA in six vessels and as a separate procedure in the other six. An average of three stents per vessel were employed. All arteries showed marked improvement at angiography. Angiographic follow-up was obtained for eight vessels in seven patients at a mean follow-up time of 12.9 months. All had patent stent lumens with neointima formation, although one stented lumen had narrowed, and another clinical failure occurred despite a patent stented vessel and an ankle-arm index (AAI) of 1.35. With a mean clinical follow-up of 9.5 months, the mean AAI for the stented extremities in the nine remaining patients is 0.91 +/- 0.15. Palmaz BEISs are effective in the management of PTA-induced human iliac artery dissection.

Adult↗