Calf deep venous thrombosis. A wolf in sheep's clothing?

To determine the natural history of calf deep venous thrombosis (C-DVT), an analytic review of the 20 relevant English-language papers published since 1942 was performed. Remarkably little methodologically sound research on this subject was found. However, available evidence suggests that C-DVT propagates to the thigh in up to 20% of cases and that propagation invariably occurs before embolization. No fatal emboli were reported in patients presenting with isolated C-DVT. Traditional anticoagulation treatment with heparin sodium and warfarin sodium of symptomatic patients with C-DVT appears to prevent extension, embolization, and early recurrence. There is no convincing evidence that C-DVT leads to chronic venous insufficiency or whether the risks of anticoagulation exceed the risks of no treatment. As an option to anticoagulation, physicians may choose to follow patients with C-DVT with serial impedance plethysmography, treating only if there is evidence of proximal extension.

Single-dose antibiotic treatment for uncomplicated urinary tract infections. Less for less?

Because of the many differences among studies of single-dose antimicrobial therapy for uncomplicated urinary tract infection in women, we reviewed the 14 randomized controlled trials on this subject. Twelve concluded that single-dose therapy was as effective as conventional multiple-dose therapy. Although the studies were carefully conducted, none both reported and ascertained in a blinded manner the incidence of adverse drug reactions. Also, no study included enough patients to prevent type II error. To circumvent the problem of having too few patients in each study, we used a rational strategy for pooling the data from the reviewed studies. Single-dose amoxicillin (3 g) was significantly less effective than conventional multidose therapy (69% vs 84%), while single-dose sulfamethoxazole-trimethoprim (two or three double-strength tablets) was indistinguishable from multidose, although there still were too few patients to exclude type II error. More research on this subject is needed with greater attention to sample size and blinded ascertainment of adverse reactions.

Optimal management of suspected lower-extremity deep vein thrombosis. An evaluation with cost assessment of 24 management strategies.

Traditionally, patients suspected to have lower-extremity deep vein thrombosis have undergone venography, which is invasive, is expensive, and may cause deep vein thrombosis in healthy individuals. Recent studies have shown the safety and efficacy of alternative noninvasive approaches that employ impedance plethysmography or real-time ultrasonography. We compared these tests using decision analysis to model the consequences of 24 different management strategies for ambulatory patients suspected to have deep vein thrombosis. We also calculated the incremental cost per additional life saved for each strategy. Our analysis revealed that the optimal approach was to perform real-time ultrasonography followed by anticoagulation therapy if deep vein thrombosis is found. This approach was both effective and cost saving compared with no testing or treatment. Serial follow-up studies of patients whose initial study suggested no DVT saved additional lives, but at a cost of $390,000 per each additional life saved for patients with one follow-up study and $3.5 million per each additional life saved for patients with a second follow-up study. Venography should play a limited role in the contemporary evaluation of patients suspected to have deep vein thrombosis. Future research should focus on the determination of clinical predictors of patients who should undergo serial examinations.

Axillary and subclavian venous thrombosis. Prognosis and treatment.

To clarify the prognosis of axillary and subclavian deep venous thrombosis and to determine which clinical factors influence its sequelae, we systematically reviewed the English-language literature published on this subject since 1950. Seventy-one case reports and 17 case series describing a total of 329 patients met our inclusion criteria for detailed review. There were major deficiencies in the quality, as well as quantity, of the available clinical data: few patients were enrolled at axillary and subclavian deep venous thrombosis inception, and outcome assessments were susceptible to bias and based on insensitive diagnostic tests. Posttreatment symptoms were reported in 34% of cases, pulmonary embolism in 9.4% (one half documented by lung scan or angiography), and death in 1.2% (three of four deaths due to pulmonary emboli). These complications occurred regardless of etiologic category (spontaneous, catheter related, or miscellaneous). Thrombolytic agents and surgery, in addition to anticoagulation, were often used to treat axillary and subclavian deep venous thrombosis, but there were no controlled trials to support any one approach. Until such trials are performed, therapy should be based on the anticoagulation regimens proved to be effective for deep venous thrombosis of the lower extremity. In selected patients, thrombolytic therapy and surgery may have important roles.

Inferior vena cava filters. Indications, safety, effectiveness.

BACKGROUND: Preventing pulmonary embolization by interrupting vena caval flow has been attempted since 1893. Inferior vena cava (IVC) filters have been available for 20 years, and currently there are five filters commercially available in the United States (Greenfield filter, Titanium Greenfield filter, Simon-Nitinol filter, Bird's Nest filter, and LGM or Vena Tech filter) and two other filters under development (Amplatz filter and Günther filter). Although these devices are widely used, their clinical utility and safety have not been completely evaluated. Controlled clinical trials to determine the clinical role for IVC filters have not been attempted, but numerous case series describing the outcomes of the seven current filters have been published. We have systematically reviewed these studies to clarify what is known about the indications, safety, and effectiveness of IVC filters. METHODS: Using the MEDLINE database, all English-language publications since 1970 that included follow-up clinical information after filter insertion were reviewed and eight methodologic guidelines were employed to assess the scientific quality of the clinical information. RESULTS: Twenty-four case series were reviewed: 16 concerned the Greenfield filter (1632 patients), and eight dealt with newer designs (925 patients). Commonly noted methodologic problems included failure to report the initial extent of thromboembolic disease, incomplete description of the patient assembly process, and incomplete and potentially biased outcome assessment. Recurrent clinical pulmonary embolism was rare after filter placement, and only eight deaths from pulmonary embolism were reported. Filter complications were common but rarely life threatening; four (0.16%) deaths from filter complications were noted among the reviewed studies. Thrombotic complications following filter placement included insertion-site deep vein thrombosis and IVC obstruction. These events were rare, but they occurred with all filter types. CONCLUSIONS: Inferior vena cava filters appear to be effective in preventing recurrent pulmonary embolism. Despite the large published experience with IVC filters, many questions remain about their indications, safety, and effectiveness. Anticoagulant therapy, if not contraindicated, should be used in conjunction with filters. While there is no ideal filter, some situations call for specific filters. Filter selection and insertion require experience, modern angiographic technique, and collaboration between clinicians caring for patients and the interventional radiologists or surgeons inserting the device.

Predictors of survival following in-hospital cardiopulmonary resuscitation. A moving target.

BACKGROUND: Counseling patients about the risks and benefits of in-hospital cardiopulmonary resuscitation (CPR) can potentially reduce patient suffering and hospital costs. However, there is currently much disagreement regarding the overall rate of in-hospital CPR survival and characteristics that identify patients more or less likely to survive CPR. METHODS: The charts of all adults who were pulseless and received basic CPR at a 720-bed university hospital during 1990 and 1991 were reviewed. Patients were excluded if cardiac arrest occurred outside the hospital or in the emergency department, operating room, recovery room, or cardiac catheterization laboratory. Each patient's chart was reviewed to determine the presence of explicitly defined clinical characteristics. RESULTS: Overall, 50 (16.0%) of 313 patients survived to discharge. Before arrest, only impaired functional capacity and sepsis identified patients unlikely to survive CPR. Of adults suffering cardiac arrest during the study period, only 22% underwent CPR, including 13.0% of those with cancer and 18.1% of those 70 years or older. CONCLUSIONS: The use of do-not-resuscitate orders to exclude patients who were inappropriate candidates for CPR may explain why the survival rate reported here is higher than similar reports and why more clinical characteristics were not found to predict CPR survival. Investigators of in-hospital CPR should use explicit criteria to describe the conditions studied and report survival for patients who receive basic CPR. The impact of do-not-resuscitate orders on survival rates must be considered. Functional capacity deserves further investigation as a predictor of CPR survival.

The role of spiral volumetric computed tomography in the diagnosis of pulmonary embolism.

To evaluate the evidence for the use of spiral volumetric computed tomography (SVCT) in the diagnosis of acute pulmonary embolism (PE), the 11 English-language studies published through July 1998 that compared SVCT with a reference standard for PE were systematically reviewed. Among the reviewed studies, methodological problems were common. Only 5 of these studies fulfilled 5 of 11 basic standards addressing important issues in diagnostic test research. The reported sensitivities of SVCT compared with pulmonary angiography varied widely (64%-93%), which was likely the result of differences in study populations. Spiral volumetric computed tomography may be relatively sensitive and specific for diagnosing central pulmonary artery PEs, but it is insensitive for diagnosing subsegmental clots. Spiral volumetric computed tomography may have a role as a "rule-in" test for large central emboli, but additional research is required to establish its place in clinical practice.

D-dimer testing and acute venous thromboembolism. A shortcut to accurate diagnosis?

D-dimer fragments can be measured easily in plasma and whole blood, and the presence or absence of D-dimer could be useful in the diagnostic evaluation of venous thromboembolism. We systematically reviewed the English literature for articles that compared D-dimer results with those of other tests for deep venous thrombosis or pulmonary embolism. Twenty-nine studies were selected for detailed review, and we noted wide variability in assay performance, heterogeneity among subjects, and failure to define absence or presence of venous thromboembolism by a comprehensive criterion standard for diagnosis. These methodologic problems limit the generalizability of the published estimates of D-dimer accuracy for deep venous thrombosis or pulmonary embolism, and the clinical utility of this potentially important test remains unproved.

Predictors of interest in prostate-specific antigen screening and the impact of informed consent: what should we tell our patients?

PURPOSE: Screening for prostate cancer with the prostate-specific antigen (PSA) remains highly controversial. We sought to discern which patient factors predict interest in the PSA and how informed consent impacts these predictors. PATIENTS AND METHODS: In a randomized trial that found that informed consent decreases patient interest in PSA screening, potential predictors of interest were analyzed separately in the uninformed (n = 102) and informed (n = 103) cohorts to examine the effects of the informational intervention. RESULTS: Univariate predictors of PSA screening interest (P < 0.05) among uninformed patients included perceived efficacy of screening, perceived seriousness of an abnormal PSA, and willingness to accept treatment risks. Among patients who had been informed about PSA screening, univariate predictors included family history of prostate cancer, perceived susceptibility to prostate cancer, age (inverse association), and perceived efficacy, although informed patients rated PSA efficacy significantly lower than uninformed patients (P < 0.001). In multivariate logistic regression modeling for the uninformed cohort, perceived screening efficacy (P < 0.001), perceived seriousness (P < 0.05), and willingness to accept treatment risks (P < 0.05) together were significant predictors of PSA screening interest. Among informed patients, perceived efficacy (P < 0.001), perceived susceptibility (P = 0.01), and younger age (P = 0.01) together predicted interest in screening. CONCLUSIONS: In contrast to uninformed patients, patients given information about PSA screening and prostate cancer are more likely to be interested in screening if they have a family history of prostate cancer, are younger, or otherwise consider themselves susceptible to developing prostate cancer. Uninformed patients are more likely to base their screening interest on the perceived seriousness of prostate cancer and on their willingness to accept treatment risks.

Technetium-99m-RBC venography in the diagnosis of deep venous thrombosis of the lower extremity: a systematic review of the literature.

We systematically reviewed the six articles from the English-language medical literature, since 1979, which compared 99mTc-RBC venography with contrast venography for the diagnosis of deep venous thrombosis (DVT) of the lower extremity. The studies were generally small in size and poorly compliant with methodologic standards for diagnostic test research. There was considerable variation in both how the 99mTc-RBC venograms were performed and how they were interpreted. Sufficient clinical information on the patients was not provided. Although the overall sensitivities and specificities were high with a mean sensitivity of 0.89 and a mean specificity of 0.84, the small numbers of patients resulted in wide 95% confidence intervals. For distal disease, with only a total of 14 patients studied, the 95% confidence intervals were particularly broad. Although 99mTc-RBC venography is a promising technique, future studies with larger numbers of patients and closer adherence to methodologic standards are required.

Methodologic problems of exercise testing for coronary artery disease: groups, analysis and bias.

To determine why exercise testing remains controversial as a diagnostic test for coronary artery disease, a methodologic review was undertaken of 33 studies comprising 7,501 patients who had undergone both exercise tests and coronary angiography. Of seven methodologic standards for research design, only one received general compliance: the requirement for an adequate variety of anatomic lesions. Less than half of the studies complied with any of the remaining six standards: adequate identification of the groups selected for study; adequate analysis for relevant chest pain syndromes; avoidance of a limited challenge group; and avoidance of work-up bias, diagnostic review bias and test review bias. Only one study met as many as five standards. These methodologic problems may explain the wide range of sensitivity (35 to 88 percent) and specificity (41 to 100 percent) found for exercise testing, because the variations could not be attributed to the usual explanations: definition of anatomic abnormality, stress test technique or definition of an abnormal test. Determining the true value of exercise testing requires methodologic improvements in patient selection, data collection and data analysis.

Effectiveness of percutaneous coronary interventions to prevent recurrent coronary events in patients on chronic hemodialysis.

Patients on chronic hemodialysis undergoing percutaneous coronary revascularization have similar rates of procedural success and in-hospital event rates when compared with a matched cohort. However, patients on chronic hemodialysis have a marked increase in 36-month target vessel revascularization, myocardial infarction, and death rates.

Plasma DNA. A simple, rapid test for aiding the diagnosis of pulmonary embolism.

Previously, we reported that the sensitivity of plasma DNA for patients with pulmonary emboli was 83 to 88 percent. To confirm these findings in a more comprehensive study, we collected plasma samples from 137 consecutive patients undergoing 148 ventilation-perfusion lung scans for pulmonary embolism. DNA was measured using a counter-immunoelectrophoresis technique that used high titer precipitating double-stranded DNA antibody from a patient with systemic lupus erythematosus. In addition to 17 patients (17 lung scans) excluded for not having plasma collected, 32 patients (37 lung scans) were excluded for having either a condition other than pulmonary embolism that could be associated with plasma DNA or for having nonacute symptoms. Eighteen of 22 patients with a diagnosis of pulmonary embolism (defined by either a high probability lung scan or abnormal pulmonary angiogram) had detectable plasma DNA. Only four of 27 patients without pulmonary embolism (defined by either a normal lung scan or normal pulmonary angiogram) had plasma DNA detected. Based on these results, plasma DNA had a sensitivity of 82 percent and a specificity of 85 percent for this condition. Plasma DNA is a promising test for pulmonary embolism and could help physicians interpret equivocal lung scan findings and thereby clarify difficult decisions such as the need for pulmonary angiography.

Vena cava filter devices.

Vena cava filters are effective in preventing pulmonary embolism (PE) in patients with deep vein thrombosis or PE who either have contraindications to anticoagulation or have sustained a PE despite adequate anticoagulation. Although vena cava filters are not without complications, clinically significant morbidity and mortality are low. The use of vena cava filters as primary prophylaxis or therapy for deep vein thrombosis and PE should await the results of controlled trials.

Healthy patients who perceive poor health: why are they worried sick?

OBJECTIVE: To explore characteristics of patients who are physically healthy but who perceive poor health by investigating the hypothesis that mental health problems, financial strain, and deficiencies in social support underlie why these patients are "worried sick." METHODS: Three hundred forty-eight continuity patients in 2 rural primary care practices were administered the PRIME-MD, the MOS SF-36, a health-related worry (1-item, 5-point) scale, the MOS social support survey, and perceived economic strain instruments. The patient's physician rated physical health on a 10-point scale. Health care utilization was defined as the number of office visits and total office and laboratory charges for 6 months before and after the interview date. RESULTS: Two hundred thirty-seven patients (group A) scored in the upper and middle terciles on the MOS health perceptions scale. One hundred eleven patients scored in the lower tercile on health perceptions: 59 (group B) were rated as having good physical health (physical health rating > 6) and 52 (group C) as having poor health (rating < or = 6). The "worried sick" patients (group B) resembled Group A with regard to physical health, but resembled the sick (group C) with regard to all MOS functional scales, prevalence of mental health diagnoses, and worry. Social support was similar across groups. Only 1 of 3 measures of economic strain was less in group A than B and C. CONCLUSIONS: Our measures of mental health problems, financial strain, and deficiencies in social support accounted only in part for the differences among the three groups. Other explanations of why some are "worried sick" require study, such as other life stressors and personality traits.

Restoring balance to internal medicine training: the case for the teaching office practice.

Medical residents require an experience beyond the tertiary care hospital to understand many aspects of contemporary medical practice and to make informed career choices. To provide this balanced training, the University of Virginia has operated for 10 years an internal medicine teaching office practice to provide an outpatient experience similar to private practice. It allows residents to work closely with general internal medicine faculty and introduces them to the knowledge and skills necessary to establish and manage a successful practice. The curriculum of the 10 week rotation includes patient care in the office and by telephone, nursing home and home visits, tutorials and seminars on primary care and office management topics, and training in the use of microcomputers. A survey of 46 (92%) of the first 50 residents completing the rotation revealed that the content of the rotation was valuable, the rotation substantially influenced career choices, and the rotation helped provide a balanced view of internal medicine practice.