Screening Asymptomatic Patients Research Articles

Perioperative myocardial infarction in noncardiac surgery: the diagnostic and prognostic role of cardiac troponins.

Despite the number of technologies used, the diagnosis of perioperative myocardial infarction is still a challenge. Studies conducted in surgical series have demonstrated that cardiac troponins (cTns) have both a superior diagnostic sensitivity and specificity, compared with other traditional techniques, and an independent power to predict short- and long-term prognosis. Nevertheless, some points need to be clarified. They include the usefulness of cTns in patients with end-stage renal failure; the standardization of the cTns cut-off for the diagnosis of myocardial injury; the timing of postoperative blood samplings; the cost-effectiveness of a screening in asymptomatic patients; and the possible therapeutic strategies.

Diagnosing coronary artery disease in diabetic patients.

Although several diagnostic modalities are available to the clinician interested in diagnosing coronary artery disease, very few have been validated in diabetic populations. This review discusses the non-invasive diagnosis of coronary disease in diabetic patients. Evidence regarding the prevalence and prognostic significance of silent ischemia is reviewed and the potential impact of silent ischemia on the diagnostic characteristics of the exercise treadmill test discussed. Other diagnostic tools are considered, and recommendations are made with respect to screening asymptomatic diabetic patients for coronary artery disease.

Cost-effectiveness of urinary dipsticks to screen asymptomatic catheter-associated urinary infections in an intensive care unit

To assess the cost-effectiveness of urinary dipsticks (UDs) to screen asymptomatic catheterized patients for quantitative urine. Prospective comparison of UD with quantitative urine culture (QUC) (reference technique) and cost-effectiveness analysis performed from the hospital's perspective. Medical intensive care unit (ICU) of the Besançon University Hospital (France). All consecutive, asymptomatic, catheterized patients. Urinary dipsticks (Multistix 8-SG) were analyzed by the reflectance spectrophotometric method (Clinitek 50). Sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of four combinations of the leukocyte (L) test pad and the nitrite (N) test pad were calculated: L and N, L or N, L alone and N alone. A micro-costing technique was used to determine the direct medical cost of each strategy. The calculated cost-effectiveness ratio was the incremental cost-effectiveness (ICE) ratio. Three hundred thirty-nine urine samples taken from 144 patients were analyzed. The incidence of asymptomatic catheter-associated urinary tract infections (CAUTIs) was 31.3% (> or =10(5) organisms/ml). The L or N combination was the best detector of asymptomatic CAUTI: Se=87.2%, Sp=61.6%, PPV=30.6% and NPV=96.1%. The cost of QUC strategy and UD strategy was EUR 21.5 and EUR 12.6 per test, respectively. The ICE ratio of QUCs was EUR 69.5 per case of detected CAUTI. The UD is a cost-effective test for screening asymptomatic catheterized patients for quantitative urine culture in a medical ICU.

9:45—10:00: Superimposition of EBCT Determined Coronary Calcium Deposits onto Myocardial PET Perfusion Images by Rubidium-82 and Nitrogen-13 Ammonia for Assessment of Flow Limiting Defects

Calcium localization by Electron Beam CT (EBCT) in the coronary arteries is becoming an important non-invasive method for screening asymptomatic patients for early coronary atherosclerosis. However, the relationship between coronary artery calcium deposits and myocardial perfusion abnormalities has not been established. We have developed software to superimpose location of coronary calcium by EBCT onto PET myocardial perfusion images, so that we can determine the role of location and amount of calcium in the arteries to flow-limiting perfusion defects by PET.EBCT and PET transaxial images are each first converted to three-dimensional arrays of 1 mm voxels. The resulting two image volumes sets are displayed so that a vertical line can be drawn from the clavicle to the spine for proper rotation of the body. The rotated images are then displayed superimposed and are shifted in the vertical, horizontal, and the long axis directions to co-register the EBCT and PET images. The EBCT images are windowed for calcium Houndsfield numbers and calcium location is added to the PET images as a maximum intensity value in the image. The modified PET image volume is then translated back to the PET data format and reprocessed using cardiac analysis software such that the calcium location is superimposed on the PET myocardial perfusion images.Preliminary results of the PET-EBCT superimposition program correlate with location of coronary calcium by EBCT and PET perfusion defects following stress. This technique may be useful for identifying flow-limiting calcium deposits in the coronary arteries.

Asymptomatic Patients at High Risk for Deep Venous Thrombosis Who Receive Inadequate Prophylaxis Should Be Screened

Patients after stroke and major orthopedic surgery have increased factors for developing deep vein thrombosis. We sought to determine the implications of screening high-risk patients to detect proximal deep vein thrombosis. We used decision analysis to determine the implications of screening vs not screening asymptomatic high risk patients with duplex ultrasonography to detect proximal deep venous thrombosis. The outcomes were bleeding, pulmonary embolism, death, and number of patients with true-positive, false-positive, and false-negative tests. Screening with ultrasonography, all asymptomatic patients who receive appropriate prophylaxis, prevalence 5%, would result in the treatment of 3.1% patients with proximal deep vein thrombosis (true positives); 2.9% without proximal deep vein thrombosis (false positives) and in the lack of diagnosis in 1.9% patients (false negatives). At a prevalence of 20%, no prophylaxis, screening would result in the treatment of 12.4% patients with proximal deep vein thrombosis (true positives), 2.4% without proximal deep vein thrombosis (false positives), and in the lack of diagnosis in 7.6% of patients (false negatives). Screening high-risk patients who receive prophylaxis is not warranted. Patients who receive no prophylaxis should be screened with ultrasonography.

Prostate-specific antigen for prostate cancer screening: Do physician characteristics affect its use?

Purpose: Screening for prostate cancer with the prostate-specific antigen (PSA) test remains controversial. This controversy is reflected in a lack of consensus in the medical literature and among professional and policy organizations regarding routine screening by PSA. It is not known how physicians respond when recommendations from experts are inconsistent. Methods: A questionnaire was mailed to 1369 primary care physicians in active practice in Washington State in 1994. Response rate to the survey was 63%. Chi-square tests and multivariate logistic regression analysis were used to examine the effects of physician characteristics on physicians’ self report of use of the PSA test for screening asymptomatic male patients, aged 50 to 80, for prostate cancer. Results: Of the 714 physicians included in the analysis, 68% reported routine use of PSA. Use of PSA varied among physicians on the basis of practice setting, years since medical school graduation, and whether compensation was fee-for-service or salaried. Male physicians trained before 1974 and physicians receiving fee-for-service were significantly more likely than other physicians to recommend screening by PSA. Conclusions: Results suggest that physicians’ personal characteristics such as year of medical school graduation, gender, and mode of reimbursement are related to self-reported PSA use.

Rapid serodiagnosis with RK39 dipstick for visceral leischmaniasis of low endemicity in northwestern china

Visceral leishmaniasis, caused by Leishmania (Leishmania) chagasi, is a chronic parasitic disease of humans and dogs. Confirmation of the protozoal agent in bone marrow, lymph node or spleen aspirate is diagnostic, while specific-IgG serology is used mainly for epidemiology despite the general presence of high levels of serum immunoglobulin. Anecdotal reports of false-negative serology in active disease cases are known and are ascribed to the formation of immune complexes. Because dissociation of immune complexes can be accomplished by acid treatment, we devised a simple, routine enzyme immunoassay (ELISA) for the dissociation of immune complexes in serum samples using acid treatment in wells adsorbed with Leishmania antigen (dELISA). Confirmatory acid dot-blot was also developed for antigen detection by anti-Leishmania rabbit antiserum. In experimental L. chagasi hamster models, immune complexes interfered with ELISA mostly in the 30 and 60 days postinfection, according to both dELISA and antigen dot-blot results. In larger samples from endemic areas, dELISA was positive in 10% of seronegative dog samples (7/70) and 3.5% in negative human samples (3/88), showing that dELISA could be used in the serodiagnosis of visceral leishmaniasis. Moreover, dELISA could be used as an alternative approach to screening asymptomatic visceral leishmaniasis patients, instead of invasive confirmatory testing.

Use of chest radiography in the initial evaluation of patients with localized melanoma.

To evaluate the use of an initial staging chest x-ray film in asymptomatic patients who present with localized primary cutaneous melanoma. The staging workup of 1032 consecutive asymptomatic patients with localized melanoma was retrospectively reviewed via database chart review. Regional melanoma referral center in an academic medical center. The melanoma database identified 1032 asymptomatic patients with localized melanoma for retrospective review. Of the patients studied, 876 (85%) of 1032 had an initial staging chest x-ray film performed. A chest x-ray film was considered initial if performed within 6 months of melanoma diagnosis. The rate of positive, negative, and suspicious findings of initial chest x-ray films. One hundred thirty (15%) of 876 patients had suspicious findings necessitating additional workup. Based on follow-up radiologic findings, only 1 (0.1%) of 876 had a true-positive chest x-ray film demonstrating pulmonary metastasis. The yield of detection of unsuspected pulmonary metastasis by chest x-ray film in the initial evaluation of asymptomatic patients with localized melanoma was exceedingly low (0.1%). Our results support the concept that routine chest radiograph screening in asymptomatic patients presenting with stage I and intermediate-thickness (1.5- to 4.0-mm) stage II melanoma is unlikely to yield true-positive findings of silent pulmonary metastasis. No definitive conclusions were drawn for the subset of patients with stage II thick melanoma (> 4.0 mm) because of the small number of patients (n = 40) in our series. Prospective studies are necessary to ultimately define the yield of initial radiographs in asymptomatic patients with localized melanoma.

Sexually transmissible diseases--knowledge and practices of general practitioners in Victoria, Australia.

OBJECTIVE: To examine knowledge and practices in relation to sexually transmissible diseases (STDs) of general practitioners (GPs) in Victoria, Australia. METHOD: A questionnaire was distributed to 520 Victorian GPs randomly...

Thoracic tumors in children with neurofibromatosis-1.

Thoracic tumors have been infrequently reported as a complication of neurofibromatosis-1 (NF1). To determine the prevalence and clinical features of thoracic tumors seen in children with NF1, we reviewed medical records and imaging studies for a group of 260 pediatric patients with NF1 followed in a multidisciplinary NF Center. Extrapleural thoracic tumors were seen in nine patients with NF1, corresponding to a prevalence of 3.5% in this hospital-based series of patients. Pathological studies of the tumors demonstrated plexiform neurofibroma in four cases and neurofibrosarcoma in one case. The remaining four cases were suspected to be plexiform neurofibroma based on clinical features but have not been confirmed histologically. Three patients presented with symptoms of chest pain, syncope, or wheezing; six patients were asymptomatic at the time of diagnosis of the tumors. Physical findings frequently found in patients with thoracic tumors were scoliosis (especially focal scoliosis) and visible plexiform neurofibromas of the neck. We conclude that NF1 patients presenting with any of these signs and symptoms should be screened for thoracic tumors with chest X-ray and magnetic resonance imaging as needed. It is unknown whether screening asymptomatic NF1 patients with chest X-rays on a regular basis will result in an improved outcome.

Screening for Carotid Artery Stenosis with the Continuous Wave Doppler Listening Examination

The Asymptomatic Carotid Atherosclerosis Study (ACAS) demonstrated that carotid endarterectomy was beneficial for selected asymptomatic patients with carotid artery stenoses greater than 60%. However, the optimal technique for identifying these asymp tomatic lesions remains undefined. Carotid duplex is the current standard, but cost limits its use for screening large populations. This study prospectively examines the audible interpretation of the continuous wave (CW) Doppler signal as a screening tool for carotid artery stenoses. Carotid artery listening examinations were performed using CW Doppler immedi ately before standard carotid duplex examinations in 207 patients (414 examinations) by two certified vascular technologists. Stenosis in the extracranial internal carotid artery was classified as <50°/a or ≥50% based on the listening examination alone, and the results were correlated with the duplex findings (duplex ≥50% stenosis—peak systolic frequency [PSF] ≥5 KHz). The results were analyzed in two groups to determine whether accuracy improved with experience (phase I: 107 patients; phase II: 100 patients). The overall sensitivity (95% confidence interval), specificity, positive predictive value, and negative predictive value of the CW Doppler listening examination compared with carotid duplex was 76% (67.4-83.8), 97% (94.4-98.6), 91% (83.0-95.6), and 92% (87.9-94.3), respectively, for the 414 examinations. The sensitivity (phase I: 68% vs phase II: 85%, P<0.05) increased during the second phase of the study although no significant change was noted in the specificity (phase I: 98% vs phase II: 96%, P=0.44), positive predictive value (phase I: 93% vs phase II: 89%, P=0.71), or negative predictive value (phase I: 89% vs phase II: 95%, P=0.11). Twenty-one of the 27 false-negative listening examinations (CW Doppler <50%, duplex ≥50%) occurred in arteries with stenoses between 50% and 69% (PSF 5-<7 KHz) on duplex. There were only six false- negative examinations among 80 lesions ≥70% on duplex (PSF ≥7 KHz). The time (2.1 ±1.0 vs 12.6 ±9.6 min, P<0.05, Student's t test) and cost ($22.95 vs $166.47) of the listening examination were both less than those of duplex. The CW Doppler carotid listening examination is an accurate, cost-effective alterna tive to the carotid duplex examination for screening asymptomatic patients for significant carotid artery stenoses.

Liver-directed therapies for gastrointestinal malignancies.

Although surgery remains the treatment of choice for hepatic malignancy, both primary and secondary, the majority of patients presenting with hepatic tumors are unfortunately not candidates for resection. A number of alternative hepatic-directed therapies are assessed for their role in the following settings: as primary treatment modalities; as treatment adjuvants to surgical resection, including neoadjuvant therapy to downstage tumors prior to planned resection; and as a means of palliation when tumors are incurable. Non-surgical hepatic-directed therapies demonstrated to prolong survival include adjuvant portal vein chemotherapy infusion at the time of resection of primary colorectal cancer, and hepatic artery infusion in the setting of established hepatic metastases. Several other therapies are described but remain incompletely evaluated, including transplantation, microwave coagulation, injection of radiolabeled particles, chemoembolization, percutaneous ethanol injection, and cryosurgery. Due to the rarity of these tumors, many studies present results of heterogeneous populations of patients, making meaningful comparison difficult. Finally, it must be said that screening asymptomatic patients after resection of colorectal cancer with a view to application of hepatic-directed therapy in the setting of colorectal metastases is costly.

Colon Cancer Screening: Sigmoidoscopy or Colonoscopy

Colorectal cancer is a common neoplasia with high morbidity and mortality. With endoscopy it is possible to identify its precursor lesion, the adenoma, and early localized cancer. Early detection and removal of adenomas can reduce the incidence and mortality of this disease. Studies using fecal occult blood testing (FOBT) and sigmoidoscopy for screening asymptomatic patients demonstrate a reduction in mortality from colorectal cancer. Colonoscopy, however, has the highest yield for detecting polyps. Most authorities and organizations now recommend screening the asymptomatic population over age 50 for colorectal neoplasia. The estimated cost of colon cancer screening is well within the benchmark figure of $40,000 per year of life saved, which is considered by the government to be cost effective. Controversies still exist regarding which colon cancer screening strategy is the most sensitive, specific, acceptable to the population, and cost effective. The American Cancer Society recommends a combination of FOBT and flexible sigmoidoscopy, but some experts believe that a one-time colonoscopy at age 60 may be a more cost-effective method. If the costs of colonoscopy are reduced, it is more cost effective than other techniques. Colonoscopy also may help to stratify at-risk patients, and those with negative initial colonoscopy may not need further screening. Advances in molecular biology may provide markers for screening or identifying people who are at high risk for colorectal neoplasia. This development may allow screening to be directed at high-risk groups.

Nasopharyngeal radium irradiation: fundamental considerations.

This article discusses the potential carcinogenic effects of radiation exposure from nasopharyngeal radium irradiation exposure and issues to consider when deciding whether to recommend screening for asymptomatic patients who have been treated by nasopharyngeal radium irradiation. The radiation exposure from the radium is primarily the result of gamma-rays, which are very penetrating. beta-Particles would affect only the tissues located within 1 cm of the eustachian tube orifice. On the basis of a quantitative risk assessment, the lifetime risk of brain cancer developing was estimated to be approximately 3 per 1000 persons, and the lifetime risk of a fatal cancer 5.6 per 1000 persons. When the medical benefits of screening asymptomatic patients are assessed, several factors, including the medical risks and benefits and cost-effectiveness of follow-up, should be considered.

Nasopharyngeal radium irradiation: Fundamental considerations

This article discusses the potential carcinogenic effects of radiation exposure from nasopharyngeal radium irradiation exposure and issues to consider when deciding whether to recommend screening for asymptomatic patients who have been treated by nasopharyngeal radium irradiation. The radiation exposure from the radium is primarily the result of γ-rays, which are very penetrating. β-Particles would affect only the tissues located within 1 cm of the eustachian tube orifice. On the basis of a quantitative risk assessment, the lifetime risk of brain cancer developing was estimated to be approximately 3 per 1000 persons, and the lifetime risk of a fatal cancer 5.6 per 1000 persons. When the medical benefits of screening asymptomatic patients are assessed, several factors, including the medical risks and benefits and cost-effectiveness of follow-up, should be considered. (Otolaryngol Head Neck Surg 1996;115:399-402.)

COLORECTAL CANCER SCREENING

The decision whether to launch a screening program in asymptomatic patients of average risk for colorectal cancer and the selection of the appropriate protocol for screening are complex issues. There are still many unanswered questions. Many organizations such as the American Cancer Society, the World Health Organization Collaborating Center for the Prevention of Colorectal Cancer, and the U.S. National Cancer Institute advocate screening with annual Hemoccult tests and screening with flexible sigmoidoscopy every 3 to 5 years in patients more than 50 years of age. The U.S. Preventive Services Task Force, the Canadian Task Force on Periodic Health Examination, and the International Union Against Cancer have not recommended screening asymptomatic average-risk patients for colorectal cancer. One study showed a small but significant benefit (3 per 1000) of the rehydrated annual Hemoccult test in reducing mortality from colorectal cancer. To embark on a mass screening strategy as recommended, however, would require significant costs, increases in physician training, improved access to the requisite technology, and enhancements in patient and physician compliance. Furthermore, the high false-positive rates of the rehydrated Hemoccult tests would lead to many unnecessary tests, causing greater expense as well as patient discomfort and anxiety. It is, therefore, premature to recommend mass screening for colorectal cancer in asymptomatic individuals at this time. Further research is needed to identify risk factors (such as genetic markers) better and to develop and evaluate screening strategies targeted at those with high risk for colorectal cancer. In the meantime, efforts at primary prevention for the general population should be increased (through nutrition and exercise). Patients over the age of 50 who desire screening should be given information of the benefits and risks of screening and together with their physicians decide on a screening strategy that suits their needs and values.

Exstrophy of the cloaca in a 47,XXX child: Review of genitourinary malformations in triple‐X patients

Cloacal exstrophy, unilateral renal agenesis, and Müllerian anomalies occurred in a liveborn infant with a 47,XXX chromosome constitution. The patient extends the range of genitourinary anomalies reported in triple-X patients. Screening asymptomatic patients for urinary tract abnormalities may be useful in searching for silent malformations potentially associated with this karyotype.

Duplex scanning in post-operative surgical patients.

The technique of duplex scanning for the diagnosis of deep venous thrombosis (DVT) has been developed in 3 stages. Initially B-mode imaging with compression was used. Subsequently interrogation of the venous lumen using the Doppler facility was introduced and finally the latter became simple and efficient with the introduction of colour flow imaging. Sensitivities and specificities in excess of 90% have been produced for thrombosis proximal to the calf by all methods in symptomatic patients. Colour flow imaging has given the best results for calf DVT in symptomatic patients with 86% sensitivity and 91% specificity. Before the introduction of colour flow imaging the accuracy for the detection of old thrombi in asymptomatic patients was poor. With the introduction of colour, sensitivities and specificities in excess of 90% have been obtained for proximal DVT; for calf DVT, sensitivity of 79% and specificity of 97% have been reported by 2 studies. If further studies substantiate these recent results duplex scanning will become the non-invasive method to be used in screening asymptomatic patients.

SCREENING FOR ASYMPTOMATIC UTI: URINE DIPSTICK IS BEST.

Several tests are available for screening asymptomatic patients for urinary tract infection, including urine dipstick testing, urinalysis, gram staining, and urine culture. This study compared these tests in 1047 consecutive pregnant …

COLORECTAL CANCER SCREENING

Colorectal cancer is a common and devastating disease. Many authorities recommend screening asymptomatic person, although the benefit of such screening is without scientific validation. Each of the screening modalities available has been examined, and their merits and shortcomings have been discussed. Surveys have indicated that primary care physicians generally agree with screening asymptomatic patients, but only a minority actually comply with the recommendations. Patient acceptance also varies. Thus, while specialty boards and panels of experts attempt to arrive at policies for the general population, primary care physicians must interact with the individual patient. Until data from ongoing prospective screening studies are available and cost-benefit issues are resolved, screening for colorectal cancer will remain at the discretion of physicians and their patients. There is insufficient evidence to support either continuing or discontinuing the recommended examinations for asymptomatic patients. The screening examinations can be recommended on the basis of a theoretical benefit, however. They can be performed with a minimum of risk of injury or side effects. Certain patients can be identified as being at above-average risk and deserving of more consideration. If aware of the benefits and limitations of colorectal cancer screening, primary care physicians can decide how to implement colorectal cancer screening in their clinical practice.