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Biomedical subjects

U Nyman

Publications and source records attributed to U Nyman.

At least 19 recordsLinked to original sources
PubMed2001

Clinically suspected pulmonary embolism: is it safe to withhold anticoagulation after a negative spiral CT?

The goal of this study was 3-month clinical outcome in nonanticoagulated patients with clinically suspected acute pulmonary embolism (PE) following a negative spiral CT. During a 6-month period 305 patients underwent spiral CT, of whom only 8 also had a lung scintigraphy. In patients with a final CT report read as not positive for acute PE, all hospital records and answers to a patient questionnaire were analyzed for episodes of venous thrombembolism (VTE). Acute PE was diagnosed at spiral CT in 61 patients (20%). Twenty-six of the remaining 244 patients were excluded from further analysis because of (a) long-term anticoagulation due to symptomatic acute deep venous thrombosis (n = 5), clinically diagnosed acute PE (n = 2), chronic recurrent VTE (n = 4), and cardiac disorders (n = 5); and (b) a normal perfusion scintigram (n = 4) or a negative pulmonary arteriogram (n = 6). Three patients were lost to follow-up. Among the remaining 215 patients only 10 had undergone a negative lower extremity venous study. Sixteen patients (7%) died during the follow-up period, 6 of whom underwent autopsy. Venous thrombembolism was diagnosed in three of the 215 patients (1.4%, 95% confidence limits: 0.5-4.0%), one causing the patient's death. Two patients had advanced thoracic malignancies and the third severe chronic obstructive pulmonary disease (84 years old). A negative spiral CT may be able to exclude clinically significant acute PE with the same accuracy as a normal lung scintigraphy or a negative pulmonary arteriography.

Acute Disease↗
PubMed2001

In vitro screening of Indian medicinal plants for antiplasmodial activity.

Plants traditionally used in India to treat fever or malaria were examined in vitro for antiplasmodial properties against Plasmodium falciparum. Of 80 analysed ethanol extracts, from 47 species, significant effects were found for 31 of the extracts. These represent 23 different species from 20 families. Of the active species 20 were tested against P. falciparum for the first time. The following five species seems to be of special interest for further antimalarial studies, Casearia elliptica, Holarrhena pubescens, Pongamia pinnata, Soymida febrifuga, and Plumbago zeylanica.

Animals↗
PubMed2000

Endovascular repair of descending thoracic aortic aneurysms: an early experience with intermediate-term follow-up.

PURPOSE: The purpose of this study was to report an initial experience with the endovascular repair of descending thoracic aortic aneurysm. Complications and intermediate-term morphologic changes were identified with the intent of altering patient selection and device design. METHODS: Endografts were placed into 25 patients at high-risk for conventional surgical repair over a 3(1/2)-year period. Devices were customized on the basis of preoperative imaging information. Follow-up computed tomography scans were obtained at 1, 3, 6, and 12 months and yearly thereafter. Additional interventions occurred in the setting of endoleaks, migration, and aneurysm growth. RESULTS: The overall 30-day mortality rate was 20% (12.5% for elective cases; 33% for emergent cases). There were 3 conversions to open repair. Neurologic deficits developed in 3 patients; 1 insult resulted in permanent paraplegia. Neurologic deficits were associated with longer endografts (P =.019). Three endoleaks required treatment, and 1 fatal rupture of the thoracic aneurysm treated occurred 6 months after the initial repair. Migrations were detected in 4 patients. The maximal aneurysm size decreased yearly by 9.15% (P =.01) or by 13.5% (P =.0005) if patients with endoleaks (n = 3 patients) were excluded. Both the proximal and distal neck dilated slightly over the course of follow-up (P =.019 and P =.001, respectively). The length of the proximal neck was a significant predictor of the risk for endoleakage (P =.02). CONCLUSION: The treatment of descending thoracic aortic aneurysms with an endovascular approach is feasible and may, in some patients, offer the best means of therapy. Early complications were primarily related to device design and patient selection. All aneurysms without endoleaks decreased in size after treatment. Late complications were associated with changing aneurysm morphologic features and device migration. The morphologic changes remain somewhat unpredictable; however, alterations in device design may result in improved fixation and more durable aneurysm exclusion.

Aged↗
PubMed2000

Does post-angiographic hemodialysis reduce the risk of contrast-medium nephropathy?

OBJECTIVE: Several strategies have been employed to reduce the incidence of nephrotoxicity in connection with the administration of urographic contrast media. We present the results of a randomized study to explore the effect of a single hemodialysis treatment immediately after an angiographic examination. MATERIAL AND METHODS: The patients studied had moderately reduced renal function. Seventeen of the 32 patients had diabetic nephropathy and 15 had other renal diseases. They were randomly selected to undergo either hemodialysis or standard treatment following the angiographic examination. The glomerular filtration rate (GFR) was determined the day before and 1 week after administration of the contrast medium. All patients were hydrated and received oral calcium-channel blocking treatment before angiography. RESULTS: Hemodialysis lowered the level of contrast medium in plasma by approximately 80%. In spite of this no significant difference in renal iohexol clearance was noted between groups treated and not treated with hemodialysis. CONCLUSIONS: The risk of a marked and sustained reduction in renal function after administration of an iodine contrast medium is low with modern angiographic techniques. Hemodialysis reduces levels of contrast media in plasma but does not reduce the incidence of contrast-medium-induced nephrotoxicity in the GFR range from 10 to 25 ml/min.

Adult↗
PubMed1999

[Spiral computed tomography--solution to diagnostic problems in pulmonary embolism?].

Clinical diagnosis of pulmonary embolism is difficult and often dependent on radiological methods. In Sweden scintigraphy has hitherto been the method most commonly used, though all too often it leaves the diagnosis in doubt. Spiral computed tomography, performed during continuous infusion of contrast medium, clearly depicts the pulmonaries arteries, emboli appearing as filling defects. The examination takes less than one minute. Although the method has yet to be fully evaluated, it is already available at most Swedish hospitals. Results presented so far suggest that the technique has great potential, and may become the method of choice in the diagnosis of pulmonary embolism.

Contrast Media↗
PubMed1999

Validity of pulmonary cine arteriography for the diagnosis of pulmonary embolism.

The aim of this study was to assess the interobserver variations in diagnosis of pulmonary embolism (PE) with cine technique and to compare the diagnostic accuracy of pulmonary arteriograms to final-outcome diagnosis. One hundred and seventy patients with clinical suspicion of acute PE were examined with ECG, laboratory tests, chest X-ray, pulmonary scintigraphy and selective pulmonary cine arteriography. The follow-up time was 6 months. Fifty-one arteriograms were interpreted as positive for PE. Two pulmonary emboli were missed when compared with the diagnosis as stated by the final-outcome committee. No arteriograms were considered as not of diagnostic quality. Mean interobserver agreement in lobar vessels was 100%, in segmental vessels 93% and in subsegmental vessels 63%. The mean interobserver agreement was 89%. Pulmonary cine arteriography produces high diagnostic accuracy and few inconclusive results in patients with suspected PE.

Angiography↗
PubMed1999

An ethnopharmacological survey for potential angiotensin converting enzyme inhibitors from Indian medicinal plants.

Plants used in different traditional systems of Indian medicine and some relatives/substitutes have been investigated for their angiotensin converting enzyme (ACE) inhibitory activity. They were selected on the basis of their usage as cardiotonics, diuretics and other uses related to the symptoms of hypertension. Out of the 73 species investigated, 22 showed more than 50% ACE inhibitory activity.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Distal migration of stent-grafts after endovascular repair of abdominal aortic aneurysms.

PURPOSE: To analyze patients after endovascular repair of abdominal aortic aneurysm (AAA) with respect to distal migration of stent-grafts and its underlying causes. MATERIALS AND METHODS: Sixty-five patients underwent endovascular repair between January 1994 and February 1997. There were seven women and 58 men, with a mean age of 71 years (range, 51-84 years). Three patients died in the perioperative period (one of myocardial infarction and two of multiorgan failure) and two patients died within 4 months of the procedure of non-procedure-related causes. In addition, two patients were followed at another hospital. The remaining 58 patients were followed up with spiral computed tomography scans at 1, 3, and 6 months, and biannually thereafter. Angiography was performed at 1 month and 1 year after the procedure and additionally when deemed clinically necessary. Mean follow-up was 29 months (range, 1-49). Migration more than 5 mm was considered significant. RESULTS: Twenty-six patients (45%) showed distal migration of stent-grafts during follow-up. Mean follow-up time at detection of migration was 13 months (range, 1-36 months). Thirteen cases of migration were ascribed to dilatation of the proximal aneurysmal neck during follow-up. Ten cases of migration were ascribed to causes other than neck dilatation or poor patient selection. In three cases, no obvious cause for the migration was found. The migration was complete in eight cases, leading to late conversion to open surgical repair. On two of these occasions, complete migration lead to aneurysm rupture. In addition, four patients received additional stent-grafts as proximal extensions. CONCLUSIONS: Distal migration of stent-grafts after endovascular AAA repair occurred frequently in this series. Dilatation of the proximal aneurysmal neck is a major cause of distal migration of stent-grafts. Improved proximal fixation is needed to secure long-term durability.

Aged↗
PubMed1999

Percutaneous placement of stents in chronic iliac and aortic occlusive disease.

OBJECTIVES: to evaluate the long-term results of stenting in iliac and aortic occlusive disease and identify factors predicting clinical outcome. DESIGN: retrospective study. MATERIALS AND METHODS: 82 patients (87 limbs) with stenoses (n =63) and occlusions (n =24) in the aortoiliac segment were treated with stents. 81 lesions involved the iliac arteries, 3 the infrarenal aorta and 3 the aortic bifurcation. Primary stenting was performed in 57 limbs (complex stenotic lesions and occlusions). Stents were placed following failed PTA in 30 limbs. Median follow-up was 13.2 months (1-66 months). RESULTS: technical success was 99% and clinical success 89%. Cumulative primary and secondary patency of stented iliac atherosclerotic lesions at 1 and 3 years was 75 and 61%, and 83 and 75% respectively. The factors predicting outcome of primary patency identified in Cox multivariate analysis were ankle-brachial index (ABI) prior stenting (p =0.03) and length of the lesion (p =0. 007). Major non-fatal complications occurred in 7.4% of the patients and there were no deaths attributed to the treatment. The 30-day mortality was 3.7%. CONCLUSION: stenting of complex aortoiliac stenoses and chronic occlusions is a safe and effective treatment modality. Long lesions and lower pre-procedure ABIs were found to negatively influence outcome.

Adult↗
PubMed1999

Abdominal aortic aneurysm morphology in candidates for endovascular repair evaluated with spiral computed tomography and digital subtraction angiography.

PURPOSE: To analyze the morphology of abdominal aortic aneurysms (AAAs) and to study the usefulness of spiral computed tomography (CT) versus digital subtraction angiography (DSA) in the evaluation of patients for endovascular repair. METHODS: Of 133 AAA patients (120 men, mean age 67 years, range 52 to 84) evaluated preoperatively with CT imaging, 77 endograft candidates (68 men) were also assessed with intra-arterial DSA. Arterial parameters were measured on axial CT scans and angiographic films for comparison. RESULTS: Mean maximum AAA diameter was 58 +/- 11 mm (range 39 to 95). Aneurysmal neck diameter was consistently smaller on DSA than on CT (20.7 +/- 3.6 mm versus 23.0 +/ 3.5 mm, p < 0.0001). The distance from the most distal renal artery to the aortic bifurcation was longer on angiography than on CT (mean difference 10.0 mm, p < 0.0001). There was a positive correlation between the maximum AAA diameter and the AAA length (r = 0.49, p < 0.0001) and an inverse relationship between the neck length and the neck diameter (r = -0.36, p < 0.0001). No correlation was found between the maximum AAA diameter and maximum iliac diameter, angulation, or length. CONCLUSIONS: AAA anatomy varies widely and independently of the aneurysm size. Therefore, the maximum size of the aneurysm is a poor predictor of whether or not an aneurysm is suitable for endovascular repair. The discrepancy between angiographic and axial CT measurements suggests that neither alone is sufficient as a preoperative imaging technique when evaluating a patient for an endovascular graft procedure.

Aged↗