Biomedical subjects
Publications and source records attributed to M E Hansen.
Chronic mesenteric ischemia caused by thrombosis of large visceral arteries due to cocaine abuse are reported in two young women. Both cases were managed successfully with visceral revascularization.
OBJECTIVE: The primary purpose of this study was to estimate the risk of HIV transmission from physicians to patients during invasive radiologic procedures and to compare this estimate with those previously derived for surgical procedures so that policy on possible practice restrictions can be decided. The risk of HIV transmission from patient to physician, including cumulative career risk for interventional radiologists, was also estimated. MATERIALS AND METHODS: The risk of HIV transmission from physician to patient and vice versa was estimated with computer modeling techniques, using available data on prevalence of HIV infection, rates of injury during invasive radiologic procedures, and risk of viral transmission after an exposure. Cumulative career risk of occupational infection was estimated with a computer simulation model. RESULTS: If the physician's HIV status is unknown, the risk of transmission of HIV to a patient during a procedure is estimated to be 0.03 per million procedures (95% confidence interval, 0-3.8 per million procedures). If the physician is known to be HIV-positive, the risk of transmission to a patient is estimated to be 7.5 per million procedures (95% confidence interval, 0-15.3 per million procedures). The estimated risk of transmission from patient to physician ranges from 0.03 to 7.5 per million for a single procedure, and the cumulative risk of occupational HIV infection over 30 years is estimated to be 0.009-16%. CONCLUSION: The estimated risk of HIV transmission from physician to patient during invasive radiologic procedures is so low that global practice restrictions on HIV-infected interventional radiologists are not warranted. As recommended by the American Medical Association and the Centers for Disease Control, decisions on possible practice restrictions should be made on a case-by-case basis rather than a priori. The risk of HIV transmission from patient to physician is also low, but real. The cumulative career risk of occupational infection with HIV may vary widely based on individual circumstances and the patient population served.
BACKGROUND: The natural history of peripheral atherosclerosis in young adults appears to be unfavorable compared with that in older patients. No universally accepted definition of "premature" atherosclerosis exists, however, making comparison of clinical studies difficult. This study examined age-related differences in distribution of atherosclerotic lesions and determined an age threshold at which such differences became apparent. Such a threshold may provide a definition of premature atherosclerosis. METHODS: Arteriograms of all patients 49 years of age and younger undergoing evaluation of lower extremity ischemia during the past 5 years were reviewed and the findings were tabulated. Medical records were reviewed to obtain demographic data, assess risk factors, and confirm disease etiology. Exclusion criteria included normal arteriograms (three patients), history of acute or remote trauma (six patients), unclear cause of ischemic symptoms (three patients), arteritis (four patients), aneurysmal disease (one patient), and acute ischemia without prior chronic symptoms (12 patients). For comparison we also reviewed arteriograms performed during the same period in 140 patients older than 50 years of age who had chronic lower extremity ischemia caused by atherosclerosis. RESULTS: The mean age of the 59 study patients was 43.4 +/- 5.8 years (median age, 46 years; range, 25 to 49 years). Arteriograms were available in all cases; medical records were available in 54 (92%). Atherosclerosis involved only the aortoiliac segment in 25 patients (42%), the femoropopliteal-tibial arteries alone in 21 (36%), and both levels in 13 (22%). Patients with distal atherosclerosis had a higher prevalence of diabetes than those with proximal atherosclerosis (p = 0.004). Ninety-two (66%) of the 140 patients older than 50 years of age had atherosclerosis confined to a single arterial segment, which was not significantly different from the prevalence of single-level disease in the study group. However, 25 (54%) of the 46 study patients with single-level atherosclerosis had aortoiliac disease compared with only 15 (16%) of 92 patients older than 50 years of age with single-level disease (p < 0.001). CONCLUSIONS: In contrast to the pattern of disease in older adults, atherosclerosis in young, nondiabetic patients most commonly involves the aortoiliac segment. Differences in lesion distribution become increasingly apparent with age but are most striking between those 49 years of age and younger and those 50 years of age and older. Accordingly, we propose that premature peripheral atherosclerosis be defined as beginning at or before the age of 49 years.
PURPOSE: The purpose of this study was to determine whether aortic size influences late patency of aortofemoral reconstructions in men and women with premature atherosclerosis. METHODS: We studied 37 consecutive young women (mean age +/- SEM, 44 +/- .7 years) and 36 young men (mean age 44 +/- .8 years) who underwent elective operations for aortoiliac occlusive disease during the past 15 years. Clinical data from patients with occluded versus patent grafts were studied, and angiographic findings in patients with occluded versus patent grafts and in young adult patients in a control group (n = 50) who had nonatherosclerotic conditions were compared. RESULTS: Twenty (54%) women and 17 (47%) men had limb occlusions within a mean of 31 +/- 6 months. These occlusions resulted in major amputations in 17 (23%) patients. When patients with occluded versus patent grafts were compared no differences were found in age, sex, symptoms, type or number of atherosclerotic risk factors, or operative details. As a whole, patients in the study group had smaller infrarenal aortas than did patients in the control group (p = 0.009). Women with limb occlusions had smaller infrarenal aortas than did women with patent grafts (p = 0.03) or healthy female patients in the control group (p = 0.002). Men with limb occlusions had smaller infrarenal aortas than did men with patent grafts (p = 0.017) or male patients in the control group (p < 0.001). Angiographic outflow scores were not different in men or women with occluded versus patent grafts. Among all variables studied proportional hazards regression analysis indicated that only mean infrarenal aortic diameter was predictive of graft patency. CONCLUSIONS: These data suggest that late graft failure after aortofemoral reconstruction is common in young adults. Patients with premature atherosclerosis have smaller infrarenal aortas compared with young adults in a control group, making them more vulnerable to symptoms from atherosclerotic lesions. Size of the infrarenal aortic segment is a critical determinant of late graft patency regardless of sex.
OBJECTIVE: To determine current use of universal precautions by practicing interventional radiologists in the United States. METHODS: National survey mailed to interventional radiologists, conducted anonymously in November 1991. Of 1530 survey forms mailed to practicing interventional radiologists, 817 (53%) were returned and 804 (52%) were completed and evaluable. Both academic and private practice settings were represented. RESULTS: Eighty-five percent of respondents had changed their use of infection control measures in the previous 10 years. Of these, 96% cited personal concerns about AIDS as a reason for making changes. Sixty-two percent made changes in response to Centers for Disease Control and Prevention and Occupational Safety and Health Administration recommendations as well. Use of barrier precautions was quite variable. Although 86% of respondents always wore a sterile gown during procedures, only 32% routinely wore a face mask or shield and only 29% of those who did not wear corrective glasses routinely wore protective eye gear during procedures. Seven percent of respondents routinely double gloved for procedures. Twenty percent of reported percutaneous injuries occurred during recapping of used sharps; an additional 6% were related to improper disposal of used sharps. CONCLUSIONS: We conclude that use of universal precautions by interventional radiologists in the United States is variable. Some practices that may lead to preventable injury to health care workers remain common.
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OBJECTIVE: Errors in reference citation and use are common in the medical and scientific literature. The prevalence of such errors in the radiology literature has not been reported. We did a study to assess the accuracy and appropriateness of use of references cited in two general radiology journals. MATERIALS AND METHODS: All references cited in the June 1993 issues of the American Journal of Roentgenology and Radiology were numbered consecutively. Fifty references were chosen at random from each journal, and copies of the original publications were obtained from the medical library at our institution or through interlibrary loan. Each reference was studied for accuracy and appropriateness of its citation in the June 1993 journal article (the "index article"). Errors were classified as major or minor in each category. Data were analyzed with the SAS statistical package. RESULTS: Forty-seven (94%) of 50 references were obtained from AJR, and 48 (96%) of 50 from Radiology. Of the 47 from the AJR, one (2%) had a major error and 21 (45%) had a minor error in accuracy. Of the 48 from Radiology, two (4%) had a major error and 11 (23%) had a minor error in accuracy. These values were significantly different for minor errors (p = .0188), but not for major ones (p = 1.000). When we adjusted for index article type, error rates for the two journals were not significantly different (p = .0612). We found four major errors (9%) and two minor errors (4%) in appropriateness of citation in the AJR references we studied. Three references (6%) from Radiology contained major errors in appropriateness of use; we found no minor errors of that type. These values were not significantly different (p = .232 for minor errors; p = .709 for major errors). One error in accuracy prevented location of the original reference. Errors were not related to the number of references cited in an index article (p = .528 for accuracy; p = .092 for appropriateness). CONCLUSION: The rate of minor errors in accuracy of references is fairly high in the two journals studied and is comparable to rates previously reported for other types of journals. The rate of major errors in accuracy of references is slightly lower than rates for other types of journals. The percentage of cited references that could not be located was also smaller than in previous reports. Errors in citation appropriateness were less common as well. Given the small number of errors that prevented references from being located, significant expenditure of time and money by journal staff members in checking references is probably not justified. However, authors should be encouraged to exercise greater care in checking all of their references for both accuracy and appropriateness of use. Differences in error rates between AJR and Radiology may have resulted in part from the random sampling method, which produced different mixtures of index articles for the two journals.
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OBJECTIVE: Possible nosocomial transmission of blood-borne pathogens is a serious concern for health care workers and patients alike. Needle-stick injuries and blood contacts pose a risk of pathogen transmission during procedures. We performed a study to determine the frequency of injuries and blood contacts during invasive radiologic procedures and to examine procedure-related factors that may increase risk of injury or exposure. SUBJECTS AND METHODS: A prospective study of needle-stick injuries and blood contacts during invasive radiologic procedures was performed. During a 10-week period, information about procedures was recorded by technologists or physicians, and needle-stick injuries and exposures to patients' blood and body fluids were noted. Data were analyzed with the SAS statistical package. RESULTS: Accidental exposure to patients' blood and body fluids occurred in 15 of 501 cases (3.0%; 95% confidence interval, 1.7-4.9%). Of 729 operators at risk, 15 were exposed (2.0%; 95% confidence interval 1.1-3.3%). Exposure was parenteral in one case and cutaneous in 14. Risk of exposure was correlated with procedure duration (p = .003), but not with emergency vs elective procedure status (p = .796), procedure type (p = .275), or operator experience level (p = .554). Three needle-stick injuries (0.6% of cases) occurred, all with sterile instruments; bleeding occurred in two cases. Risk of injury was correlated only with procedure type (p = .046). In no case was a patient exposed to a physician's blood. CONCLUSION: Whereas cutaneous exposure of physicians to patients' blood was not infrequent, parenteral exposure was rare in this series. Most of the exposures in this study could have been prevented by the use of protective equipment. Patients' contact with physicians' blood did not occur in this study.
Because the intact surgical glove is an important barrier against exposure to blood and other body fluids, occult glove perforations occurring during procedures may have implications for infection control and protection of health care workers. Although the frequency of occult glove perforations during surgery has been studied, no such data have been reported for interventional radiology. This study was designed to determine the frequency of occult glove perforations in interventional radiology. Gloves used during interventional radiologic procedures were collected and tested for occult perforations according to previously accepted methods. The frequency of occult defects in unused gloves was also determined. A form completed for each pair of gloves indicated length of use, awareness of perforations, and information about the procedure. The anatomic distribution of perforations was also studied. Occult perforations were found in 49 (10%) of 492 used gloves. The frequency of defects in unused gloves was 1% (2/160). Gloves worn fewer than 2 hr had a perforation rate of 7% (29/406), and those worn 2 hr or longer had a rate of 23% (20/86; p less than .0001). Perforations were noticed by the wearer in only three (6%) of the 49 perforations. The perforation rate for inner gloves of a double-glove set was 3% (1/34; the corresponding outer glove also was perforated). Although the 10% rate of occult glove perforation during interventional radiologic procedures found in this series is lower than rates described with surgical procedures, it is not insignificant. The significant increase in the rate of perforation when gloves are worn more than 2 hr suggests that gloves should routinely be changed at or before 2 hr of wear, particularly in procedures involving high-risk patients.
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Use of the transfemoral route for venous catheterization has been considered contraindicated in patients with inferior vena caval (IVC) filters. The transjugular route has been used instead in such patients when subsequent diagnostic or therapeutic procedures are required. Many radiologists, however, are more accustomed to the transfemoral approach, and may not find the transjugular route a desirable alternative. We describe seven patients with previously placed IVC filters in whom the transfemoral route was used to perform pulmonary arteriography (five patients) or to place additional IVC filters (two patients). After venographic confirmation of caval patency, filters were catheterized under fluoroscopic control and the procedures were performed. All procedures were technically successful; no complications occurred. We believe the transfemoral route to be a safe and feasible approach for performing venous procedures in selected patients with IVC filters, obviating the less familiar and potentially more hazardous transjugular approach.
Mesenteric varices can appear as massive, acute lower gastrointestinal bleeding. The small bowel or colon may be involved, varices usually developing at sites of previous surgery or inflammation in patients with portal hypertension. Two patients with alcoholic cirrhosis and protal hypertension presented with rectal bleeding. Tc-99m RBC studies demonstrated varices and extravasation into the adjacent bowel. The varices were documented by mesenteric angiography. Characteristic features of Tc-99m labeled RBC studies can identify mesenteric varices as the cause of intestinal bleeding and localize the abnormal vessels.
To assess the accuracy of MR imaging in the evaluation of patients with suspected thoracic venous obstruction, hospital records and MR studies of 31 such patients were reviewed. Gradient-recalled echo, spin-echo, or cine MR techniques were used. In 26 of the 31 patients, venous obstruction was confirmed by CT, venography, sonography, surgery, or autopsy. Causes included tumor invasion, compression of veins, coagulopathy, or indwelling catheters. MR detected an abnormality of the superior vena cava in all 16 cases in which it was seen on other tests. Abnormality of the internal or external jugular veins was detected in all six cases in which other studies were abnormal. Abnormality of veins in the shoulder region was detected by MR in 10 of 12 patients in whom such disease was seen on other tests. The two interpretive errors were caused by nonocclusive clot, short (less than 2-cm) occlusions, and metallic artifact. Overall, MR correctly identified abnormality in 32 of 34 vessels (sensitivity, 94%). In all cases, a negative MR study was found to be a true negative (no false positives in 42 normal vessels; specificity, 100%). We conclude that MR is an accurate means of assessing patency of the thoracic inlet and mediastinal veins. Its noninvasive nature and multiplanar capability contribute to its usefulness in this clinical setting.
Twenty-one embolizations were performed in 19 children and adolescents. Ten patients underwent emergency embolotherapy to control bleeding from trauma (5), neoplastic disease (2), mycotic aneurysm (1), post-operative bleeding (1), and hemoptysis (1). Nine patients underwent elective embolotherapy. In 5 patients with hypervascular tumors, it was performed as an adjunct to surgery or chemotherapy. In 3 patients, embolotherapy was the primary mode of treatment for vascular malformations in the lung, pelvis, and kidney. One patient with systemic-pulmonary arterial collaterals was treated for high-output congestive heart failure. Embolotherapy was successful in controlling bleeding in all cases. There were no major complications or procedure-related mortalities. Minor complications occurred in 2 patients. Our results indicate that percutaneous transcatheter embolotherapy in children and adolescents is safe and effective and has wide application in both elective and emergency management of vascular lesions in this age group.
In a group of 211 schoolchildren in Queensland less than 12 years of age, the mean total melanocytic nevus (mole) count was 28 (median 19), and the mean count for raised nevi was 11 (median 8). The upper aspect of the back and chest were the most commonly affected sites, with the neck being the third. Boys had significantly (p less than 0.01) more melanocytic nevi than girls, and prevalence was highest in children with pale skin and light-colored hair. Nonwhite heritage had a protective effect independent of pigmentary characteristics. Total numbers of nevi on children also were related to maternal tendency to large numbers of moles and to family history of melanoma. The only significant association observed for the presence of large (greater than 5 mm) nevi on children was a family history of melanoma. The children studied come from a general population that has the highest known risk of melanoma. In Australia they have been shown to have the highest prevalence of nevi ever reported in the prepubertal age group. These descriptive data, together with the specific pigmentary and family associations described, extend the known links between benign nevi and malignant melanoma.
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