Silverstein, Marc D.

Abstract In response to concerns about inappropriate testing and healthcare costs, clinicians and laboratorians should work together to evaluate laboratory tests. Studies of routine laboratory tests ordered for screening and case-finding in the preoperative setting, at hospital admission, and in the ambulatory setting have not provided sufficient evidence of the benefits of case-finding when evaluated against commonly used criteria for screening procedures. We adapt a conceptual framework developed from radiology for evaluating imaging technologies to evaluate laboratory tests. The framework addresses diagnostic efficacy (whether the test correctly identifies abnormalities), diagnostic effectiveness (whether the test changes the physician's diagnoses), therapeutic efficacy (whether the test changes patient management), and therapeutic effectiveness (whether the test changes patients' outcomes). We propose that clinicians and laboratorians use this framework to evaluate the diagnostic efficacy, diagnostic effectiveness, therapeutic efficacy, and therapeutic effectiveness of laboratory tests in the ambulatory setting and in other settings.

Objective: To compare an expert panel's global assessment of appropriateness of elective surgery for abdominal aortic aneurysms (AAA) with their assessment of the effect of surgery on the probability of 5-year mortality. Methods: Nine expert panel members rated the appropriateness of 120 scenarios for elective AAA repair on a nine-point scale, and also estimated the 5-year probability of AAA-related death and of non-AAA related death among 30-day survivors of AAA surgery and among patients with unoperated AAA. These probabilities were used to determine differences in 5-year probability of mortality of surgery vs. no surgery for each scenario. Three categories of appropriateness were defined based on these differences: inappropriate (< 0%), equivocal (0-5%), and appropriate (>5%). Results: The distribution of scenarios was inappropriate (39%), equivocal (12%), and appropriate (49%) based on probability estimates and inappropriate (43%), equivocal (22%), and appropriate (36%) based on global assessment. There was poor agreement between the two methods, with a Kappa coefficient=0.28 (95% CI: 0.23 to 0.32). Although a higher proportion of scenarios were rated as appropriate using probability estimation rather than global judgment, the level of agreement among members of the panel was similar, Kappa coefficient= 0.07 (95% CI: — 0.07 to 0.72) Conclusions: Experts disagree about the appropriate indications for elective surgery for AAA. Explicit estimates used in a decision analysis may provide a better assessment of appropriate indications than the global judgment of experts. Global assessment of the appropriateness of AAA surgery based on panel members' review of research evidence for increased survival appears to include implicitly their valuation of outcomes.

The role of venous stasis syndrome (VSS) mechanisms (i.e. venous outflow obstruction [VOO] and venous valvular incompetence [VVI]) on quality of life (QoL) and activities of daily living (ADL) is unknown. The objective of this study was to test the hypotheses that venous thromboembolism (VTE),VSS,VOO and VVI are associated with reduced QoL and ADL. This study is a follow-up of an incident VTE case-control study nested within a population-based inception cohort of residents from Olmsted County, MN, USA, between 1966 and 1990. The study comprised 232 Olmsted County residents with a first lifetime VTE and 133 residents without VTE. Methods included a questionnaire and physical examination for VSS; vascular laboratory testing for VOO and VVI; assessment of QoL by SF36 and of ADL by pertinent sections from the Older Americans Resources and Services (OARS) and Arthritis Impact Measurement Scales (AIMS2) questionnaires. Of the 365 study participants, 232 (64%), 161 (44%), 43 (12%) and 136 (37%) had VTE, VSS, VOO and VVI, respectively. Prior VTE was associated with reduced ADL and increased pain, VSS with reduced physical QoL and increased pain, and VOO with reduced physical QoL and ADL.VVI was not associated with QoL or ADL. In conclusion,VSS and VOO are associated with worse physical QoL and increased pain. VOO and VTE are associated with impaired ADL. We hypothesize that rapid clearance of venous outflow obstruction in individuals with acute VTE will improve their QoL and ADL.

Abstract Venous stasis syndrome may complicate deep vein thrombosis (DVT; i.e. post-phlebitic syndrome), but, in most cases, venous stasis syndrome is not post-phlebitic. The objective of this study was to determine the risk factors (including prior DVT) for venous stasis syndrome, and to assess venous outflow obstruction and venous valvular incompetence as possible mechanisms for venous stasis syndrome. This was a case–control study nested within a population-based inception cohort. The study population consisted of 232 Olmsted County, MN residents with a first lifetime venous thromboembolism (VTE) and 133 residents without VTE. Measurements included a questionnaire and physical examination for venous stasis syndrome; strain gauge outflow plethysmography, venous continuous wave Doppler ultrasonography and passive venous drainage and refill testing for venous outflow obstruction and venous valvular incompetence. Altogether, 161 (44%), 43 (12%), and 136 (38%) subjects respectively, had venous stasis syndrome, venous outflow obstruction and venous valvular incompetence. Independent risk factors for venous stasis syndrome included increasing patient age and body mass index (BMI), prior DVT, longer time interval since DVT, and varicose veins. Both venous outflow obstruction ( p = 0.003) and venous valvular incompetence ( p < 0.0001) were strongly associated with venous stasis syndrome. Increasing age and prior DVT were significantly associated with venous outflow obstruction, while prior DVT, varicose veins and venous stasis syndrome diagnosed prior to the incident DVT were significantly associated with venous valvular incompetence. The risks of venous outflow obstruction, venous valvular incompetence and venous stasis syndrome were higher with left leg DVT. In conclusion, increasing patient age and BMI, prior DVT (particularly left leg DVT), longer time interval since DVT and varicose veins are independent risk factors for venous stasis syndrome. Venous stasis syndrome related to DVT is due to venous outflow obstruction and venous valvular incompetence, while venous stasis syndrome related to older age and to varicose veins is due to venous outflow obstruction and to venous valvular incompetence, respectively.