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S C Krämer

Publications and source records attributed to S C Krämer.

At least 19 recordsLinked to original sources
PubMed2005

Generalized arteriopathy in patients with cervical artery dissection.

OBJECTIVE: To make an ultrastructural comparison of superficial temporal artery (STA) biopsy specimens from patients with spontaneous cervical artery dissection (sCAD) and controls. METHODS: The authors used light microscopic examination of semithin sections and electron microscopic examination of ultrathin sections of STA biopsy specimens from patients with sCAD and controls. RESULTS: STA biopsy specimens from patients with sCAD taken around the time of the dissection showed a zone of connective tissue weakening with fissuring at the junction between the tunica media (TM) and the tunica adventitia (TA) in seven of nine specimens and erythrocyte infiltration in eight of nine specimens but in none of the control specimens. Light microscopy demonstrated transparent circular spots that, on electron microscopy, turned out to represent erythrocytes and other cellular components at different stages of degradation. Occasionally, scattered immune cells were found in specimens from patients with sCAD. In addition, smooth muscle cells of the synthetic phenotype, some of them showing extensive vacuolation were more common in the TM of STA biopsy specimens from patients with sCAD than in control specimens. CONCLUSIONS: Signs of tissue weakening along the TM/TA junction in STA biopsy specimens of patients with sCAD but not in controls suggest the presence of a generalized arteriopathy leading to impairment of the stability of the arterial wall in patients with sCAD. Limiting factors of the study are that some control biopsies were obtained from autopsies and that the anticoagulation status of patients and controls were not completely comparable.

Adult↗
PubMed2005

[Incidence of cerebral ischemia in patients with suspected cervical artery dissection: first results of a prospective study].

PURPOSE: Aim of this prospective study was to investigate the incidence of spontaneous cervical artery dissection (sCAD) and cerebral ischemia in patients with suspected sCAD by using a combined head-neck MR-imaging protocol. MATERIALS AND METHODS: 51 consecutive patients (24 m, 27 f, mean age 39.5 years, range 18 - 55 yrs) admitted to our stroke unit with suspected sCAD according to clinical criteria and age < 55 years underwent a combined head and neck MR examination within 24 hours of admission (Gyroscan Intera 1.5 T, Philips). Head MRI included ax FLAIR, ax T (1), ax DWI and TOF angiography (imaging time 12 min). Neck MRI consisted of ax T1w-TSE, T2w-TSE, contrast enhanced T1w-TSE and CE-MRA (imaging time 17 min). Three radiologists assessed both studies in consensus with regard to the presence of sCAD and acute ischemia. RESULTS: One patient had to be excluded because of motion artefacts. In 17 of 50 patients sCAD was diagnosed, and in 20 of 50 patients cerebral ischemia. In 5 patients cerebral ischemia was caused by sCAD. CONCLUSION: The proposed combined MR protocol allows imaging work-up of patients with suspected sCAD within approximately 30 min, resulting in conclusive information about the status of the extracranial vasculature and the presence of ischemia. The high incidence of patients with definite sCAD and the low incidence of cerebral ischemia indicates the necessity of an early definite diagnosis in order to start timely anticoagulation to prevent development of stroke.

Acute Disease↗
PubMed2003

[Non-occlusive mesenteric ischemia].

The so-called non-occlusive disease (NOD) or non-occlusive mesenteric ischemia (NOMI) is a severe and life-threatening pathology. Even under optimal circumstances and standardised diagnostic and therapeutic procedures maximum survival rates do not exceed 50 %. The NOD is a pathology of the elder patient and its incidence rises with other comorbidities such as reduced cardiac output, diabetes and renal insufficiency. Induction of the disease with a severe vasoconstriction of the splanchnic vessels may be a simple cardiac decompensation, a frequent trigger however is a previous heart surgery with consecutive cardiac shock. Early diagnosis is difficult to conduct because of unspecific symptoms. Beside abdominal pain in awake patients, ileus or subileus is remaining the single acute symptom which could be also a consequence of a postoperative paralysis. Laboratory parameters such as leucocytosis and elevated lactat levels are often positive, but unspecific and the latter may be a delayed sign of progressive disease. The only sufficient method for diagnosis implicating a possible treatment option seems to be an immediate angiographic examination. Because of the disappointing results of a solitary surgical approach transarterial medication via catheter is indicated. Depending of the course of the disease only a combination of local mesenteric infusion of vasodilatory drugs and surgical resection of already necrotic bowel promises a successful therapeutic approach and better survival rates.

Abdominal Pain↗
PubMed2002

[The contribution of MRI to the detection of endovascular aneurysm repair].

PURPOSE: Evaluation of MR-imaging in the follow-up of patients after endovascular repair of abdominal aortic aneurysms concerning detection of endoleaks. MATERIALS AND METHODS: In the postoperative follow-up after endovascular repair of aortic aneurysms, 10 consecutive patients (mean age: 68 years) were suspected to have an endoleak by helical CT and were scheduled for conventional angiography, preceded by supplemental MR-imaging to confirm or refute the diagnosis. The images of helical CT and MRI were evaluated by two independent readers concerning leak, feeding vessel and artifacts. RESULTS: The follow-up MRI was able to detect all endoleaks (type 1 endoleak, n = 7; type 2 endoleak, n = 3) compared to all but one detected by helical CT. Of the 10 patients with an endoleak, MR-angiography visualized the feeding vessel in 7 patients and CT in one patient. MRI did show fewer metal artifacts from the stent wire than CT. For the visualization of feeding vessels and endoleaks, MRA achieved statistically significant superiority. In a single case, helical-CT was not reliable because of strange metal artefacts after previous coil embolization. CONCLUSION: MRI is comparable to helical-CT in detecting endoleaks and superior to CT in demonstrating the anatomy of the feeding vessel after endovascular repair of aortic aneurysms. The major advantages are fewer artifacts after coil embolization and absent radiation exposure.

Aged↗
PubMed2001

Geometric changes in aortic endografts over a 2-year observation period.

PURPOSE: To report geometric changes in bifurcated aortic endografts observed over a 2-year follow-up period. METHODS: Twenty-two patients (21 men; mean age 68 years, range 57-83) with abdominal aortic aneurysms were treated with an endovascular stent-graft. Follow-up examinations included spiral computed tomographic scanning postoperatively and at 3, 6, 9, 12, 18, and 24 months after treatment. Geometric changes were measured using 3-dimensional reconstructed images in anteroposterior (AP) and lateral projections. Locations for the measurements were the proximal neck, the midportion of the endograft, and the graft limbs at the origin of the iliac arteries. RESULTS: Lateral changes predominated, demonstrating maximum angles on the side of the inserted left limb. For the proximal neck, the stent angle changed by a mean -0.71 degrees in the AP and 4.0 degrees in the lateral projection. At the midgraft, changes were -0.56 degrees for AP and 12.5 degrees for lateral. The right limb showed an angle of 6.43 degrees in AP and -0.43 degrees in lateral, whereas the left limb angles changed 1.38 degrees in AP and 11.71 degrees in the lateral plane after 2 years. There was no statistically significance difference in these changes from baseline. CONCLUSIONS: Aortic endografts are exposed to a significant amount of movement after insertion, but the resultant changes are very inhomogeneous, unpredictable, and ongoing even after 2 years. The most vulnerable location seems to be the attachment zone of the modular graft limb. These geometric changes might be one cause for late complications, including leaks and limb dislocations.

Aged↗
PubMed2001

Percutaneous techniques for managing maldeployed or migrated stents.

PURPOSE: To report our experience in the percutaneous management of dislocated endovascular stents. METHODS: During a 6-year period, 28 (2.7%) patients with a maldeployed or migrated endovascular stent (20 Palmaz, 5 Wallstent, 2 Memotherm, and 1 AVE) were recognized among 1021 patients undergoing noncardiac vascular stent procedures. Percutaneous stent management was performed using balloon catheters, gooseneck snares, grasping forceps, or additional stent implantation on the basis of the stent type, degree of expansion, mechanical characteristics, and location of the stent. RESULTS: Three stents that embolized into the pulmonary artery were left in situ, but percutaneous management was successful in 23 (92%) of the remaining 25 dislocated stents (12 venous and 13 arterial stents). Twelve stents were repositioned in an alternate, stable position or the primarily intended location; 4 stents were anchored by a second stent, and 7 stents were removed percutaneously. In the 2 failed cases, the stents were retrieved using a minor surgical procedure. There were 2 minor groin hematomas but no secondary complications during a median follow-up of 26.2 months (range 1-62). CONCLUSIONS: Percutaneous management of migrated or maldeployed endovascular stents is highly effective with few complications. On the basis of our findings, these techniques should be considered the therapy of choice.

Adult↗
PubMed2001

Endovascular interventions on persistent sciatic arteries.

PURPOSE: To report our experience with interventional procedures used to treat complete and incomplete persistent sciatic arteries (PSA). CASE REPORTS: Three female patients with PSAs displayed varying symptoms referable to this rare anatomical variant. In the first woman, a 1-year history of intermittent lower limb ischemia and an acute event prompted angiography, which demonstrated proximal occlusion of 2 crural vessels and a partially thrombosed sciatic artery aneurysm. To prevent further embolism, the aneurysm was excluded with a stent-graft. Endograft patency and aneurysm exclusion have been maintained up to 22 months. In a 41-year-old diabetic with chronic limb ischemia and digital gangrene, a flow-limiting stenosis of the sciatic artery was stented, restoring adequate pedal perfusion. The stent remained patent at the 18-month follow-up. The third patient suffered from a tumor-related pelvic hemorrhage originating from retrograde perfusion through the PSA, which had been ligated during previous surgery. Attempted embolization via a collateral connection between the incomplete PSA and the popliteal artery failed, and the patient died. CONCLUSIONS: Vasculopathies involving the sciatic artery are uncommon but may be amenable to interventional techniques, such as coil embolization and stent implantation. PSA aneurysm exclusion with a stent-graft may represent a new therapeutic alternative to standard surgery that obviates potential sciatic nerve damage, but the durability of the repair remains to be determined.

Adult↗
PubMed2000

Diagnosis of papillomas of the breast: value of magnetic resonance mammography in comparison with galactography.

The aim of this study was evaluation of MRI alone and in combination with mammography and galactography in the diagnosis of intraductal papillomas. From 1994 to 1998, a total of 48 women presenting with pathologic mammary secretion underwent galactography and magnetic resonance mammography (MRM). Thirty-five patients aged 16-71 years (average age 46 years) subsequently underwent surgery or diagnostic puncture and the histologic findings were compared with the results of the radiologic examination. Histology revealed papillomas in 16 cases. In 6 of these patients, there was associated malignant degeneration. Malignancy without associated papilloma was observed in 3 cases. Galactography displayed a sensitivity of 94% and a specificity of 79% with five false-positive findings and one false-negative finding in the recognition of intraductal papillomas. Malignant processes were detected by mammography/galactography in only one instance. Magnetic resonance mammography visualized pathologic contrast medium uptake in 8 of 9 cases of malignant disease (sensitivity 89%). One patient with in situ ductal carcinoma escaped detection with MRM. Papillomas showed no or below-the-threshold-lying contrast uptakes with no specific sign suggestive of papilloma. Galactography in combination with mammography remains the primary diagnostic procedure in cases of pathologic mammary secretion or suspected papilloma. The addition of MRI permits exclusion of malignant disease with a high degree of certainty; thus, expectant management in individual cases with negative findings appears justified.

Breast↗
PubMed2000

Embolization for gastrointestinal hemorrhages.

Retrospective evaluation of interventional embolization therapy in the treatment of gastrointestinal hemorrhage over a long-term observation period from 1989 to 1997. Included in the study were 35 patients (age range 18-89 years) with gastrointestinal bleeding (GI) referred for radiological intervention either primarily or following unsuccessful endoscopy or surgery. Sources of GI bleeding included gastric and duodenal ulcers (n = 7), diverticula (n = 3), erosion of the intestinal wall secondary to malignancy (n = 6), vascular malformations (n = 4), and hemorrhoids (n = 2), as well as from postoperative (n = 6), posttraumatic (n = 2), postinflammatory (n = 4) or unknown (n = 1) causes. Ethibloc (12 cases) or metal coils (14 cases) were predominantly used as embolisates. In addition, combinations of tissue adhesive and gelfoam particles and of coils and Ethibloc were used (six cases). Finally, polyvinyl alcohol particles, a coated stent, and an arterial wire dissection were utilized in one case each. Bleeding was stopped completely in 29 of 35 cases (83%). In one case (3%) the source of bleeding was recognized but the corresponding vessel could not be catheterized. In five other cases (14%) there was partial success with reduced, though still persistent, bleeding. The rate of complications was 14%, including four instances of intestinal ischemia with fatal outcome in the first years, and, later, one partial infarction of the spleen without serious consequences. Gastrointestinal hemorrhage can be controlled in a high percentage of patients, including the seriously ill and those who had previously undergone surgery, with the use of minimally invasive interventional techniques. The availability of minicoils instead of fluid embolization agents has reduced the risk of serious complications.

Adolescent↗
PubMed2000

Treatment of leaks after endovascular repair of aortic aneurysms.

PURPOSE: To evaluate leaks after the endovascular repair of aortic aneurysms and treat them with occlusive therapy. MATERIALS AND METHODS: Seventy patients (11 women, 59 men), aged 26-82 years (mean, 69.2 years), underwent transfemoral insertion of endoluminal stent-grafts for treatment of aortic aneurysms. Indications were traumatic pseudoaneurysms (n = 5) or arteriosclerotic aneurysms (n = 65). Aneurysms were thoracic (n = 5) or infrarenal (n = 65). To exclude the possibility of leaks, spiral computed tomography (CT) was performed at 3-month intervals. Patients with leaks that persisted unchanged longer than 3 months were referred for angiography and occlusive therapy. RESULTS: At CT, 21 leaks were identified in 17 of 70 patients (24%). Only 11 of those 17 patients (65%) had leaks identified with conventional aortography. Selective angiography, however, depicted all of these. Eighteen of 21 leaks proved amenable to occlusive treatment: surgery (n = 1), further stent implantation (n = 4), or embolization (n = 13). In one leak, spontaneous occlusion occurred after 3 months. Two leaks in either the iliolumbar or the median sacral artery were inaccessible; one remained untreated, and the other was unsuccessfully treated. Mean follow-up of occlusive therapy was 6.8 months (range, 2-14 months). CONCLUSION: Successful occlusion of perigraft leaks is feasible in most cases and can be performed without major complications.

Adult↗
PubMed2000

CT and arteriography in the evaluation of indirect myocardial revascularization with a free-muscle transplant: initial experience.

PURPOSE: To examine patients with advanced cardiovascular disease with radiology after indirect myocardial revascularization with a free-skeletal-muscle transplant and to determine whether the attached vessel remains patent over the middle and long terms. MATERIALS AND METHODS: In 10 patients with advanced, inoperable cardiovascular disease treated with indirect myocardial revascularization with a free-muscle transplant, radiologic follow-up was performed postoperatively and every 6 months. All 10 patients underwent selective arteriography of the anastomosed vessel and contrast material-enhanced helical computed tomography (CT) (transverse sections and reconstructions). RESULTS: All patients showed adequate vascular conditions postoperatively, as did nine of 10 patients after 1 year. In one patient, the anastomosed artery was occluded. CT showed time-dependent muscle degeneration in all patients. Postoperative, contrast-enhanced, superselective CT showed an area of high-attenuating uptake in the muscle transplant in all patients. After 1 year, CT depicted perfusion defects of the skeletal muscle in two patients. In eight patients, however, small vascular bridges from the skeletal muscle to the myocardium were detected. Radiologic results correlated well with clinical outcome and stress electrocardiograms. CONCLUSION: Helical intraarterial CT and arteriography were sensitive in depicting enhancement and remaining vital function in nine of 10 patients after indirect myocardial revascularization with a free-muscle transplant. This combination seems promising for postoperative examination in such patients.

Aged↗
PubMed1999

[Interventional treatment of hemorrhages in advanced cervical carcinoma].

PURPOSE: Retrospective evaluation of percutaneous interventional treatment of locally advanced cervical carcinoma. MATERIALS AND METHODS: Since 1991, 13 patients with advanced tumor disease have been referred to our department for diagnosis and therapy of an acute blood loss. In all patients (age 40-88 years, mean 61 years) hemorrhage was detected by decrease in red blood cell count. In all cases patients suffered from locally advanced or recurrent disease after surgery and/or additional radio- or chemotherapy. Embolization was performed by transfemoral access using minicoils in most cases, liquid agents less often and a covered vascular stent in one patient. RESULTS: The site of the hemorrhage or the blood pooling of the tumor could be seen in all cases angiographically. Twenty-seven treatment cycles (2.1 per patient) were performed at intervals of 3 days to 6 months. The maximum time of follow-up and additional treatments if necessary was 1 year. In 9 of 13 patients (69%) the bleeding could be stopped immediately with a single treatment or initial treatment via both iliac arteries. One patient (7,7%) died during therapy because of an uncontrollable bleeding and consecutive decrease in red blood cells count. The remaining three patients (23%) showed slight persistent or recurrent bleeding, which could be managed interventionally until the following episode. There were two complications (15%) during therapy, representing a coil misplacement and a coil wash-out, which both could be managed interventionally. CONCLUSION: Hemorrhage following locally advanced or recurrent cervical carcinoma can be stopped interventionally in about 70% of cases. Even in partial success it is possible to manage the acute life-threatening situation. Follow-up examinations of up to 1 year justify this therapeutic concept.

Adult↗
PubMed1999

[3D endosonography to clarify distal ureteral processes].

PURPOSE: Evaluation of 3D endoluminal sonography as a diagnostic modality in lower ureteral pathologies. MATERIALS AND METHODS: Between December 93 and December 97, 36 consecutive patients with negative findings on IVP and still suspected ureteral obstruction were referred for transrectal or transvaginal endosonography. Patients mean age was 63 years and all of them presented clinically obvious symptoms such as colic pain and miction disturbances. RESULTS: In 31 of 36 patients (86%) 3D endosonography was diagnostic although previous IVP was negative. Reasons for ureteral obstructions were ureteral calculi in 23, urological tumours in 5 and rectal carcinoma in two cases. In one patients a gynecological tumour caused the symptomatology. In the remaining 5 patients CT/MRT or invasive retrograde ureterography/ureteroscopy had to be performed for the final diagnosis. CONCLUSIONS: The use of 3D endosonography shows encouraging results in the diagnosis of distal ureteral pathologies. In case of negative findings on IVP it should therefore precede invasive diagnostic modalities or cost intensive imaging techniques.

Adult↗
PubMed1999

Pancreas: does hyoscyamine butylbromide increase the diagnostic value of helical CT?

Among 50 patients referred for helical computed tomography (CT) of the pancreas, 24 randomly selected patients received 40 mg of hyoscyamine butylbromide to evaluate whether its administration improved image quality and diagnostic findings. Differences between the groups were not statistically significant. It was therefore concluded that hyoscyamine butylbromide does not contribute a diagnostic advantage at helical CT of the pancreas.

Adult↗
PubMed1999

Leakages after endovascular repair of aortic aneurysms: classification based on findings at CT, angiography, and radiography.

PURPOSE: To ascertain whether the configuration and location of leakages identified at computed tomography (CT) could provide evidence of their angiographically and fluoroscopically confirmed causes. MATERIALS AND METHODS: Fifty patients aged 26-79 years underwent endovascular repair of traumatic (n = 4) or arteriosclerotic (n = 46) aortic aneurysms (four thoracic, 46 infrarenal). Radiographic examinations in three planes and helical CT were performed 1 week after implantation and every 3 months thereafter. Angiography was performed when there was evidence of a leakage at CT. RESULTS: CT demonstrated evidence of leakages in 13 patients. Broad-based leakages immediately adjacent to the prosthesis were termed "perigraft leakages." If the area most affected by the leakage lay along the border of the aneurysm, then retrograde leakages were apparent at angiography. If the leakage was ventral to the prosthesis, then its source was the inferior mesenteric artery; if it was dorsolateral, then it was supplied by either the lumbar arteries or the median sacral artery through the hypogastric artery. One circumferential leakage could not be evaluated adequately at CT or angiography. Radiography depicted a rupture of the stent mesh in the middle of the prosthesis. Selective angiography demonstrated all types of leakages and permitted CT classification. CONCLUSION: The cause of a leakage can be determined with CT on the basis of its configuration and location in the majority of cases.

Adult↗
PubMed1998

[The percutaneous transarterial embolization therapy of traumatic kidney hemorrhages].

PURPOSE: To demonstrate the possibility of transarterial, superselective embolization after traumatic kidney injury and hemorrhage in patients usually treated by surgery. METHODS: In a series of 16 patients aged 21 to 86 years (mean 37 years) external trauma led to kidney damage and consecutive bleeding. After diagnostic angiography (5 F) the exact site of hemorrhage was detected and treated by superselective embolization via a coaxial catheter system (2.7 F) either by coils (n = 5) or liquid agents (ethibloc, n = 11). RESULTS: In all patients bleeding was stopped interventionally. Additional surgical treatment was not necessary in any case. In one older patient with preinterventionally known reduced kidney function, the excretion function decreased to creatinine levels of about 3.6 mg/dl after therapy and led to compensated nephric insufficiency. Other complications were not observed. CONCLUSION: Interventional embolization is a well-tolerated and effective treatment modality after traumatic kidney hemorrhage. After exclusion of other injuries obligate for surgery, percutaneous transarterial therapy may help to avoid an operation. This reduces the risk of narcosis and treatment especially in multimorbid patients.

Adult↗