Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pretesting”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2006

Unified rate-dependent atrioventricular nodal function: consistent recovery and fatigue properties revealed with S1S2S3 protocols and different recovery indexes.

BACKGROUND: Rate-dependent nodal properties are commonly assessed with premature protocols performed at different basic rates. Because characteristics of responses differ with recovery time index, the true nature of nodal rate-dependent properties is elusive. OBJECTIVES: The purpose of this study was to reveal consistent nodal rate-dependent properties regardless of selected recovery index. METHODS: With S(1)S(2)S(3) protocols, we independently varied basic and pretest cycle lengths and thereby distinguished cumulative from noncumulative effects of rate on nodal conduction time in rabbit heart preparations. Nodal responses to 30 basic and pretest cycle length combinations (five with identical basic and pretest cycles as in standard protocols) were analyzed using both atrial (AA) and His-atrial (HA) intervals as recovery index. RESULTS: AA and HA curves had an identical shape for any of 30 steady-state conditions. When assessed with constant pretest cycle lengths, cumulative effects (fatigue) of shortened basic cycle lengths were also independent of recovery index. Shortening of pretest cycle length at fixed basic rates led to apparent inhibitory and facilitatory effects when assessed with AA and HA curves, respectively. These effects vanished when a single long cycle was inserted after the pretest cycle. In all responses including those obtained with standard protocols, combined effects of basic and pretest cycle lengths set nodal conduction time. CONCLUSION: S(1)S(2)S(3) protocols reveal consistent nodal recovery and fatigue properties regardless of recovery index used. Changes in nodal function curves arising from the use of different recovery indexes mainly depend on pretest effects. This study provides a new approach to a unified interpretation of nodal recovery and fatigue properties.

Analysis of Variance↗
PubMedDate not supplied

Cost-effective selection of patients for coronary angiography.

In patients suspected of having coronary artery disease (CAD), noninvasive testing has been playing an increasing role in selecting patients who would require coronary angiography for either the "definitive" diagnosis of CAD or as a prelude to planning myocardial revascularization. A mathematic model is presented that defines cost-effective utility of nuclear cardiology testing for diagnosis of CAD and selection of appropriate candidates for coronary angiography, according to quantitative methods of decision analysis. Clinical utility or effectiveness was defined in terms of percent correct diagnosis of CAD. Cost was defined as dollars of medical expenditure. Six competing strategies were compared in subsets of patients with different pretest likelihoods of CAD, based on age, sex, and symptoms. Nuclear cardiology testing was the most cost-effective initial modality of choice in patients with an intermediate pretest likelihood of CAD. In patients with a low pretest likelihood of CAD, nuclear cardiology testing was cost-effective in the subgroup of patients who had abnormal exercise treadmill electrocardiograms. In patients with a high pretest likelihood of CAD, direct referral to coronary angiography was the most cost-effective strategy for diagnosis of CAD. Coronary angiography, however, is performed most often as a prelude to myocardial revascularization. Because these invasive procedures are indicated only in patients who are at high risk with medical therapy, nuclear cardiology procedures, by virtue of incremental prognostic information, identify appropriate candidates for more invasive procedures, aimed at improving survival. Strategies for cost-effective prognostication of CAD depend on not only the patient's pretest likelihood of CAD but also the status of the rest electrocardiogram. In patients with a normal rest electrocardiogram, a low pretest likelihood of CAD indicates a low risk for cardiac events with medical therapy. Therefore coronary angiography is not indicated in these patients. Patients with an intermediate likelihood of CAD should first undergo exercise electrocardiographic testing; a negative response would indicate a low risk for cardiac events and a positive response would indicate the need for nuclear cardiology testing for further cost-effective risk stratification. In patients with a high pretest likelihood of CAD, the combined exercise electrocardiographic and nuclear cardiac testing is the most cost-effective strategy; a negative or a positive nuclear test result would imply low or high risk, respectively. The latter patients would then be candidates for coronary angiography. In all patients with an abnormal rest electrocardiogram, the most cost-effective strategy is uniform referral to nuclear cardiac testing (which is performed in conjunction with exercise electrocardiography), regardless of the pretest likelihood of CAD; a negative or a positive nuclear test result would indicate low or high risk for coronary events, respectively. The latter group would be proper candidates for referral to coronary angiography.

Adult↗
PubMed1999

Application of a diagnostic clinical model for the management of hospitalized patients with suspected deep-vein thrombosis.

The purpose of this study was to evaluate whether the determination of pretest probability using a simple clinical model and the SimpliRED D-dimer could be used to improve the management of hospitalized patients with suspected deep-vein thrombosis. Consecutive hospitalized patients with suspected deep-vein thrombosis, had their pretest probability determined using a clinical model and had a SimpliRED D-dimer assay. Patients at low pretest probability underwent a single ultrasound test. A negative ultrasound excluded the diagnosis of deep-vein thrombosis whereas a positive ultrasound was confirmed by venography. Patients at moderate pretest probability with a positive ultrasound were treated for deep-vein thrombosis whereas patients with an initial negative ultrasound underwent a single follow-up ultrasound one week later. Patients at high pretest probability with a positive ultrasound were treated whereas those with negative ultrasound underwent venography. All patients were followed for three months for the development of venous thromboembolic complications. Overall, 28% (42/150), and 10% (5/50), 21% (14/71) and 76% (22/29) of the low, moderate and high pretest probability patients. respectively, had deep vein thrombosis. Two of 111 (1.8%; 95% CI = 0.02% to 6.4%) patients considered to have deep vein thrombosis excluded had events during three-month follow-up. Overall 13 of 150 (8.7%) required venography and serial testing was limited to 58 of 150 (38.7%) patients. The negative predictive value of the SimpliRED D-dimer in patients with low pretest probability was 96.2%, which is not statistically different from the negative predictive value of a negative ultrasound result in low pretest probability patients (97.8%). Management of hospitalized patients with suspected deep-vein thrombosis based on clinical probability and ultrasound of the proximal deep veins is safe and feasible.

Cohort Studies↗
PubMedDate not supplied

The preliminary result of the training course of pediatric advanced life support.

To improve the preparedness of health care providers in pediatric resuscitation and to evaluate the effectiveness of the Pediatric Advanced Life Support course, we followed the standard guidelines of American Heart Association to conduct the first 10-hour course of Pediatric Advanced Life Support course in our hospital and designed this study. A total of 160 doctors and nurses were enrolled in the providers course held on Jan. 11, 1998. A pretest, posttest and survey questionnaire were given to each participant. One hundred and twenty-nine completed these tests. The average scores were 73.1 for the pretest and 86.8 for the posttest. The average scores on the pretest and posttest among doctors (n = 57) and nurses (n = 72) are 72.6, 86.7 and 73.5, 86.8, respectively (p < 0.001). In the participants with pretest score of less than 80 (n = 92), the mean values of pretest and posttest scores were 69.0 and 86.4. The participants with pretest scores higher than or equal to 80 (n = 37) had pretest and posttest mean values of 83.3 and 87.7. The participants with less background knowledge (pretest < 80) had better increment scores after this course (p < 0.05). The mean posttest scores in those working in private clinics and having 20 years of working experience are 74.0 and 72.0 (lower than the criteria for successful completion of written examination). We conclude that this provider course did increase the knowledge and skill pertaining to pediatric resuscitation personnel, particularly in participants with less background knowledge. The participants from private clinics or with working experience more than 20 years need a repeatedly educational PALS training course.

Adolescent↗
PubMed2003

Does this patient have pulmonary embolism?

CONTEXT: Experienced clinicians' gestalt is useful in estimating the pretest probability for pulmonary embolism and is complementary to diagnostic testing, such as lung scanning. However, it is unclear whether recently developed clinical prediction rules, using explicit features of clinical examination, are comparable with clinicians' gestalt. If so, clinical prediction rules would be powerful tools because they could be used by less-experienced health care professionals to simplify the diagnosis of pulmonary embolism. Recent studies have shown that the combination of a low pretest probability (using a clinical prediction rule) and a normal result of a D-dimer test reliably excludes pulmonary embolism without the need for further testing. OBJECTIVE: To evaluate and demonstrate the accuracy of pretest probability assessment for pulmonary embolism using clinical gestalt vs clinical prediction rules. DATA SOURCES: The MEDLINE database was searched for relevant articles published between 1966 and March 2003. Bibliographies of pertinent articles also were scanned for suitable articles. STUDY SELECTION: To be included in the analysis, studies were required to have consecutive, unselected patients enrolled; participating physicians in the studies, blinded to the results of diagnostic testing, had to estimate pretest probability of pulmonary embolism; and validated diagnostic methods had to be used to confirm or exclude pulmonary embolism. DATA EXTRACTION: Three reviewers independently scanned titles and abstracts for inclusion of studies. An initial MEDLINE search identified 1709 studies, of which 16 involving 8306 patients were included in the final analysis. DATA SYNTHESIS: A clinical gestalt strategy was used in 7 studies, and in the low, moderate, and high pretest categories, the rates of pulmonary embolism ranged from 8% to 19%, 26% to 47%, and 46% to 91%, respectively. Clinical prediction rules were used in 10 studies, and 3% to 28%, 16% to 46%, and 38% to 98% in the low, moderate, and high pretest probability groups, respectively, had pulmonary embolism. CONCLUSIONS: The clinical gestalt of experienced clinicians and the clinical prediction rules used by physicians of varying experience have shown similar accuracy in discriminating among patients who have a low, moderate, or high pretest probability of pulmonary embolism. We advocate the use of a clinical prediction rule because it has shown to be accurate and can be used by less-experienced clinicians.

Adult↗
PubMed1981

Developmental aspects of 2-way shuttlebox avoidance in the spontaneously hypertensive and normotensive rat.

In experiment I, male and female rats from the spontaneously hypertensive (SHR) and Wistar-Kyoto (WKYN) normotensive strains were given I session of 2-way shuttlebox avoidance training at 25-26, 35-36, or 45-46 days of age. The avoidance training was preceded by a pretest which consisted of 10 presentations of the compound conditional stimulus alone in order to assess any differential tendency of the 2 strains to respond to the presentation of novel stimuli. The WKYN rats made a significantly higher number of pretest avoidance responses and achieved a higher level of avoidance performance than SHR rats. In addition, during the pretest, WKYN rats were more active and had a shorter 1st trial latency. In Experiment II, the pretest phase was replicated with a manipulation of the intensity of the auditory cue. Although the WKYN rats had a higher rate of pretest avoidance than SHR rats, the rate of pretest avoidances increased with intensity in both strains. The WKYN rats had a shorter 1st trial latency and a shorter median latency for the 10 trials and were more active that SHR rats during the pretest. These results relate to age-independent behavioral characteristics of these strains and the question of reactivity to environmental stimulation.

Acoustic Stimulation↗
PubMed1989

Is anisomycin-induced amnesia for a passive avoidance task in chicks the result of state-dependent learning?

Many studies suggest that protein synthesis is required for formation of long-term memory. To test whether the protein synthesis inhibitor anisomycin (ANI) actually inhibits long-term memory formation or whether apparent amnesia could be attributed to state-dependency, chicks were both trained and tested under the influence of anisomycin (ANI). Two-day-old cockerels were trained in a 1-trial passive avoidance task. Intracerebral injections (10 microliters per hemisphere) of either saline (SAL) or 11.0 mM ANI were made into the medial hyperstriatum ventrale 5 min pretraining and 5 min pretest. The ANI inhibited cerebral protein synthesis by 70-80%, a level necessary to cause amnesia. Chicks that pecked a small bead dipped in methylanthranilate (MeA) and were injected with SAL both pretraining and pretest avoided pecking at test, showing memory for the bitter substance; chicks given ANI pretraining and SAL pretest pecked at the bead during test, which suggests amnesia. However, those given ANI both pretraining and pretest showed marked avoidance at test. Chicks trained to peck at a small bead dipped in water and given injections of either SAL or ANI pretraining and SAL pretest pecked readily at test. However, water-trained chicks given ANI pretest, regardless of pretraining injection, showed significantly higher avoidance at test. We conclude that peck aversion in the ANI-MeA-ANI group was not due to state-dependency but to generalized avoidance induced by pretest ANI.

Amnesia↗
PubMed2000

Subsequent investigation and management of patients with intermediate-category and -probability ventilation-perfusion scintigraphy.

The authors wished to determine the proportion of patients with intermediate-category and intermediate-probability ventilation-perfusion scintigraphy (IVQS) who proceed to further imaging for investigation of thromboembolism, to identify the defining clinical parameters and to determine the proportion of patients who have a definite imaging diagnosis of thromboembolism prior to discharge from hospital on anticoagulation therapy. One hundred and twelve VQS studies performed at the Flinders Medical Centre over a 9-month period were reported as having intermediate category and probability for pulmonary embolism. Medical case notes were available for review in 99 of these patients and from these the pretest clinical probability, subsequent patient progress and treatment were recorded. Eight cases were excluded because they were already receiving anticoagulation therapy. In the remaining 91 patients the pretest clinical probability was considered to be low in 25; intermediate in 30; and high in 36 cases. In total, 51.6% (n = 47) of these patients (8% (n = 2) with low, 66% (n = 20) with intermediate, and 69.4% (n = 25) with high pretest probability) proceeded to CT pulmonary angiography (CTPA) and/or lower limb duplex Doppler ultrasound (DUS) evaluation. Of the patients with IVQS results, 30.7% (n = 28) were evaluated with CTPA. No patient with a low, all patients with a high and 46% of patients with an intermediate pretest probability initially received anticoagulation therapy. This was discontinued in three patients with high and in 12 patients with intermediate clinical probability prior to discharge from hospital. Overall, 40% of patients discharged on anticoagulation therapy (including 39% of those with a high pretest probability) had a positive imaging diagnosis of thromboembolism The results suggest that, although the majority of patients with intermediate-to-high pretest probability and IVQS proceed to further imaging investigation, CTPA is relatively underused in this group. Most patients with a high pretest clinical probability receive anticoagulation therapy irrespective of imaging findings, and less than half of all patients discharged from hospital on anticoagulation therapy have a positive imaging diagnosis of thromboembolism.

Angiography↗
PubMed2003

A Bayesian argument against rigid cut-offs in electrodiagnosis of median neuropathy at the wrist.

BACKGROUND: Nerve conduction (NC) tests, using rigid cut-offs separating normal from abnormal test values, are commonly used to confirm median neuropathy at the wrist (MNW). The authors studied patients with clinically defined mild MNW and a normal median distal motor latency to determine 1) how much sensory or mixed NC test results increase (or decrease) the probability of MNW and 2) the NC test values required to confirm (or exclude) MNW for the range of pretest probabilities of MNW. METHODS: Palmar, digit 4 (D4), and digit 2 (D2) median NC tests were reviewed in 125 hands with mild carpal tunnel syndrome (CTS) and 100 control hands with musculoskeletal pain. Receiver operating characteristic curves and interval likelihood ratios were plotted for the three tests. Using Bayes theorem, post-test probability of MNW was then determined for the range of pretest probabilities and NC test values. RESULTS: Receiver operating characteristic curves showed that for a set specificity of 97%, palmar and D4 studies had higher electrodiagnostic utility than D2 studies with cut-off test values (sensitivities of 0.3 msec, 64.0%; 0.4 msec, 71.2%; and 50 m/sec, 44.8%). However, Bayesian analysis showed that to confirm MNW more conservative cut-off values (palmar 0.5 msec, D4 0.7 msec, D2 44 m/sec) were required for pretest probabilities or=75%. Conversely, normal test values could exclude MNW only for pretest probabilities <25%. CONCLUSIONS: For a given NC test value, post-test probability of MNW can be determined from the estimated pretest probability (derived from clinical data), interval likelihood ratios, and Bayes theorem. Use of rigid cut-off values to confirm MNW is problematic, because more conservative cut-offs are required for low pretest probability. Conversely, NC tests with sensitivity <95% cannot exclude MNW when pretest probability is high.

Adolescent↗
PubMed2000

Intraclass correlations from a community-based alcohol prevention study: the effect of repeat observations on the same communities.

OBJECTIVE: School- and community-based alcohol prevention programs are often evaluated using a group-randomized trial (GRT) design with a single pretest and a single posttest survey. To size such studies properly, investigators need accurate estimates of the variance and intraclass correlation that will be operative in their analyses. Until recently, the only available estimates were based on cross-sectional analyses. A recent report suggests that values from cross-sectional analyses may overestimate the intraclass correlation operative in pretest-posttest analyses. The purpose of this article is to review these issues, present estimates of intraclass correlation for a variety of alcohol-related endpoints based on cross-sectional analyses and to compare those estimates to estimates based on pretest-posttest analyses. We will also show how these estimates can be used to establish optimal sample sizes for GRTs to evaluate school- and community-based alcohol prevention programs. METHOD: Data were collected from 18 to 20 year olds and high-school seniors as part of an alcohol prevention effort employing a group-randomized trial design with a single pretest and a single posttest survey. Data were analyzed via mixed-model regression methods to estimate components of variance. Those components were then used to compute the intraclass correlations operative in both cross-sectional analyses and in pretest-posttest analyses. RESULTS: Results indicate that intraclass correlations operative in pretest-posttest analyses are much smaller than are those operative in cross-sectional analyses. CONCLUSIONS: Our findings indicate that future alcohol-prevention studies employing a group-randomized trial design with a single pretest and single posttest survey may not need to be as large as previously suggested by intraclass correlation estimates based on cross-sectional data. This holds true even if they are analyzed to reflect the extra variation typical of group-randomized trials.

Adolescent↗
PubMed2003

Cost-effectiveness of alternative management strategies for patients with solitary pulmonary nodules.

BACKGROUND: Positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) is a potentially useful but expensive test to diagnose solitary pulmonary nodules. OBJECTIVE: To evaluate the cost-effectiveness of strategies for pulmonary nodule diagnosis and to specifically compare strategies that did and did not include FDG-PET. DESIGN: Decision model. DATA SOURCES: Accuracy and complications of diagnostic tests were estimated by using meta-analysis and literature review. Modeled survival was based on data from a large tumor registry. Cost estimates were derived from Medicare reimbursement and other sources. TARGET POPULATION: All adult patients with a new, noncalcified pulmonary nodule seen on chest radiograph. TIME HORIZON: Patient lifetime. PERSPECTIVE: Societal. INTERVENTION: 40 clinically plausible combinations of 5 diagnostic interventions, including computed tomography, FDG-PET, transthoracic needle biopsy, surgery, and watchful waiting. OUTCOME MEASURES: Costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. RESULTS OF BASE-CASE ANALYSIS: The cost-effectiveness of strategies depended critically on the pretest probability of malignancy. For patients with low pretest probability (26%), strategies that used FDG-PET selectively when computed tomography results were possibly malignant cost as little as 20 000 dollars per QALY gained. For patients with high pretest probability (79%), strategies that used FDG-PET selectively when computed tomography results were benign cost as little as 16 000 dollars per QALY gained. For patients with intermediate pretest probability (55%), FDG-PET strategies cost more than 220 000 dollars per QALY gained because they were more costly but only marginally more effective than computed tomography-based strategies. RESULTS OF SENSITIVITY ANALYSIS: The choice of strategy also depended on the risk for surgical complications, the probability of nondiagnostic needle biopsy, the sensitivity of computed tomography, and patient preferences for time spent in watchful waiting. In probabilistic sensitivity analysis, FDG-PET strategies were cost saving or cost less than 100 000 dollars per QALY gained in 76.7%, 24.4%, and 99.9% of computer simulations for patients with low, intermediate, and high pretest probability, respectively. CONCLUSIONS: FDG-PET should be used selectively when pretest probability and computed tomography findings are discordant or in patients with intermediate pretest probability who are at high risk for surgical complications. In most other circumstances, computed tomography-based strategies result in similar quality-adjusted life-years and lower costs.

Algorithms↗
PubMed1999

Significance of the role of self-study and group discussion.

The study of anatomy is experiencing a reduction in course duration and content, lecture and dissection hours, and number of lectures and examinations. This necessitates that medical students develop skills for self-study. Toward that end, a self-study module in basic anatomy was tested. Fifty-seven new entrants were given a pretest (Pretest A) containing a questionnaire on basic anatomy. Then, in three groups each of 11 and two groups each of 12, they learned basic anatomy from recommended books in the library by self-study for 2 hours. They discussed what they had learned among their group members during a practical exercise, followed by a posttest (Posttest A). A control group of 57 new entrants during another year was given the same pretest (Pretest B) and a lecture on basic anatomy. Then, without opportunity for self-study, they were given a posttest (Posttest B). The answers were scored out of 40. The students' mean mark in Pretest A was poor. All the groups performed well in the practical exercise. In Posttest A, the mean mark increased significantly (P < 0.001), by 9.4. It shows that self-study and group discussions significantly helped the students in construction of core anatomical knowledge as well as the acquisition, assimilation, and application of anatomical concepts and content. The mean mark in Pretest B was also poor. In Posttest B, the mean mark increased significantly (P < 0.001), by 14.2. This indicates that the traditional teaching session is also useful and serves to advance student knowledge. Thus our innovative study module can create a positive learning environment and can become an alternative to traditional instruction in teaching anatomical terminology and basic anatomy.

Adult↗
PubMed2002

The effects of adenosine receptor agonists and antagonists on morphine state-dependent memory of passive avoidance.

Pretraining administration of morphine (5 mg/kg, intraperitonically) in a step-down passive avoidance task led to state-dependent learning with impaired retrieval on the test day that was dose-dependently restored by pretest administration of morphine (0.5, 1, 3, and 5 mg/kg). This restoration was reversible by pretest naloxone administration. Pretest administration of adenosine receptor antagonists theophylline or 8-phenyltheophylline (8-PT) did not alter morphine-induced amnesia. However, both the antagonists inhibited the restoration of memory by pretest morphine (5 mg/kg). Adenosine A(1) receptor agonists N(6)-cyclohexyladenosine (CHA) or N(6)-phenylisopropyladenosine (R-PIA) only at the higher doses used, and adenosine A(2) receptor agonist 5'-N-ethylcarboxaminoadenosine (NECA), at all doses used, decreased morphine-induced amnesia in a dose-dependent manner. Pretest administration of low doses of CHA, R-PIA, or NECA significantly showed additive effects with low dose pretest morphine (1 mg/kg) in restoring memory. The promnestic effects of high-dose CHA and R-PIA were inhibited by theophylline or 8-PT but not by naloxone. The additive effects of low-dose CHA or R-PIA and morphine were inhibited by theophylline, 8-PT, or a higher dose of naloxone. The promnestic effect of NECA and its additive effect with low-dose morphine were both inhibited by theophylline and naloxone but not by 8-PT. It is concluded that activation of the adenosinergic system, through both A(1) and A(2) receptors, can reverse morphine-induced amnesia and is involved in morphine state of memory.

Adenosine↗
PubMed1989

Discovery of antidepressant activity by forced swimming test may depend on pre-exposure of rats to a stressful situation.

Antidepressant-induced anti-immobility effects have been assessed in animals exposed or not to a pretest session using the forced swimming test. Desipramine, maprotiline, mianserine (15 and 30 mg/kg), nomifensine (2.5 and 5 mg/kg), d-amphetamine (1 and 2 mg/kg) and muscimol (1 and 2 mg/kg), unlike imipramine (15 and 30 mg/kg), LY-171555 (0.1 and 0.2 mg/kg) and scopolamine (0.5 and 0.1 mg/kg), did not reduce immobility time in rats which had not received the pretest session. On the other hand, all of the drugs tested reduced immobility time in rats exposed to a pretest session. In addition, the degree of antiimmobility effects of desipramine (20 mg/kg) and nomifensine (5 mg/kg) increased proportionally with the level of water (0, 4, 15 and 30 cm) to which animals were exposed at the time of pretest. Furthermore, desipramine reduced immobility time in rats pre-exposed to types of stress different from forced swimming, cold, restraint or foot-shock. All drugs were injected intraperitoneally three times, 24, 5 and 1 h before testing. The present findings suggest that a stressful pretest session may reveal pharmacological properties of antidepressants in the forced swimming test. This is also substantiated by the fact that diazepam (2.5 and 5 mg/kg) administered 30 min before the swimming pretest antagonized the anti-immobility effect of 15 mg/kg desipramine.

Animals↗
PubMed2006

Cost effectiveness of coronary angiography and calcium scoring using CT and stress MRI for diagnosis of coronary artery disease.

We compared the cost effectiveness of recent approaches [coronary angiography and calcium scoring using computed tomography (CT) and stress magnetic resonance imaging (MRI)] to the diagnosis of coronary artery disease (CAD) with those of the traditional diagnostic modalities [conventional angiography (CATH), exercise ECG, and stress echocardiography] using a decision tree model. For patients with a 10% to 50% pretest likelihood of coronary artery disease, non-invasive coronary angiography using CT was the most cost effective approach, with costs per correctly identified CAD patient of euro4,435 (10% likelihood) to euro1,469 (50% likelihood). Only for a pretest likelihood of 30% to 40% was calcium scoring using CT more cost effective than any of the traditional diagnostic modalities, while MRI was not cost effective for any pretest likelihood. At a pretest likelihood of 60%, CT coronary angiography and CATH were equally effective, while CATH was most cost effective for a pretest likelihood of at least 70%. In conclusion, up to a pretest likelihood for coronary artery disease of 50%, CT coronary angiography is the most cost-effective procedure, being superior to the other new modalities and the most commonly used traditional diagnostic modalities. With a very high likelihood for disease (above 60%), CATH is the most effective procedure from the perspective of society.

Adult↗
PubMed2004

Usefulness of clinical prediction rules for the diagnosis of venous thromboembolism: a systematic review.

PURPOSE: To summarize the evidence on the predictive value of clinical prediction rules for the diagnosis of venous thromboembolism. METHODS: We selected all studies in the English literature in which a clinical prediction rule was prospectively validated against a reference standard, and calculated likelihood ratios, predictive values, and the area under the receiver operating characteristic (ROC) curve for each prediction rule. RESULTS: Twenty-three studies met our eligibility criteria: 17 evaluated prediction rules for the diagnosis of deep venous thrombosis and six evaluated rules for pulmonary embolism. The most frequently evaluated prediction rule for deep vein thrombosis was the Wells rule, which had median positive likelihood ratios of 6.62 for patients with a high pretest probability, 1 for moderate pretest probability, and 0.22 for low pretest probability. The median area under the ROC curve was 0.82. Addition of the D-dimer test to the prediction rule increased the median area under the curve to 0.90. The Wells prediction rule was the most commonly studied for pulmonary embolus and had median positive likelihood ratios of 6.75 for those with high pretest probability, 1.82 for moderate pretest probability, and 0.13 for low pretest probability. The median area under the ROC curve was 0.82. CONCLUSION: The Wells prediction rule is useful in identifying patients at low risk of being diagnosed with venous thromboembolism. The addition of a rapid latex D-dimer assay improved the overall performance of the prediction rule.

Clinical Trials as Topic↗
PubMed2004

The predictive characteristics of D-dimer testing in outpatients with suspected venous thromboembolism: a Bayesian approach.

BACKGROUND: Despite the widespread use of quantitative methods to measure D-dimer, clinical decisions commonly are based only on binary test information (positive/negative). This study aimed to determine the significance of quantitative D-dimer results in the evaluation of venous thromboembolism (VTE) by means of a differentiated Bayesian approach. METHODS: Prospective study in 118 outpatients referred for workup of suspected pulmonary embolism (n = 75) or deep vein thrombosis (n = 43). The sensitivity and specificity of D-dimer results obtained by DD VIDAS (Biomerieux, France), STA Liatest (Diagnostica Stago, France), and D-dimer plus (Dade, US) were assessed for five different cut-offs. Further, predictive values and multilevel likelihood ratios were calculated in order to assess the operative test characteristics in excluding or confirming VTE. RESULTS: At a cut-off of 500 ng/ml and pretest probabilities < 47%, the VIDAS provides a negative predictive value (NPV) > 95%, whereas a positive predictive value (PPV) > 95% is obtained in patients with a D-dimer > 10,000 ng/ml and pretest probabilities > 50%. At a cut-off of 500 ng/ml and pretest probabilities < 33%, the Liatest exhibits a NPV > 95%, whereas a PPV > 95% is obtained in patients with a D-dimer >10,000 ng/ml and pretest probabilities > 37%. Finally, with the D-dimer plus, a NPV > 95% is seen at a cut-off of 150 ng/ml and pretest probabilities < 30%, whereas a PPV > 95% is obtained at a cut-off > 1000 ng/ml and pretest probabilities > 67%. CONCLUSIONS: D-dimer measurements in outpatients cannot only allow for exclusion but, in some situations, also for confirmation of venous thromboembolism. It is therefore advisable to conduct a quantitative interpretation of D-dimer results.

Aged↗
PubMed1985

Prognostic significance of normal quantitative planar thallium-201 stress scintigraphy in patients with chest pain.

The prognostic significance of normal quantitative planar thallium-201 stress scintigraphy was evaluated in patients with a chest pain syndrome. The prevalence of cardiac events during follow-up was related to the pretest (that is, before stress scintigraphy) likelihood of coronary artery disease determined on the basis of symptoms, age, sex and stress electrocardiography. In a consecutive series of 344 patients who had adequate thallium-201 stress scintigrams, 95 had unequivocally normal studies by quantitative analysis. The pretest likelihood of coronary artery disease in the 95 patients had a bimodal distribution. During a mean follow-up period of 22 +/- 3 months, no patient died. Three patients (3%) had a cardiac event: two of these patients (pretest likelihood of coronary artery disease 54 and 94%) had a nonfatal myocardial infarction 8 and 22 months, respectively, after stress scintigraphy, and one patient (pretest likelihood 98%) underwent percutaneous transluminal coronary angioplasty 16 months after stress scintigraphy for persisting anginal complaints. Three patients were lost to follow-up; all three had a low pretest likelihood of coronary artery disease. It is concluded that patients with chest pain and normal findings on quantitative thallium-201 scintigraphy have an excellent prognosis. Cardiac events are rare (infarction rate 1% per year) and occur in patients with a moderate to high pretest likelihood of coronary artery disease.

Adult↗