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A Perrier

Publications and source records attributed to A Perrier.

100 records · Page 6Linked to original sources
PubMed1995

[Contribution of laboratory tests and venous investigations in the diagnosis of pulmonary embolism].

The diagnostic strategy of pulmonary embolism is based firstly on pulmonary scintigraphy, a non-invasive investigation which provides a definitive diagnosis in about 30% of patients, and then on pulmonary angiography, which remains the investigation of reference. However, new diagnostic methods have been introduced in order to reduce the number of angiographies. Measurement of plasma D-dimer, a fibrin degradation product, enables exclusion of the diagnosis in 20-50% of patients without pulmonary embolism when the result is normal on ELISA (< 500 micrograms/l with the commercialized Stago test). This is due to the very high sensitivity of D-dimer: in a compilation of recent series with a total of 1,159 patients suspected of having pulmonary embolism, their concentration was over the threshold of 500 micrograms/l in 96% (CI 95%, 93-98) of patients with pulmonary embolism. On the other hand, their low specificity makes them useless for a positive diagnosis of the condition. Lower limb venous compression ultrasonography enables detection of proximal deep venous thrombosis in about 57% (CI 95%, 52-62) of patients with pulmonary embolism, posing the indication for anticoagulation without further investigations because of its high specificity (98%) (CI 95%, 97-99). When venous ultrasonography is normal, however, pulmonary embolism cannot be excluded. A diagnostic strategy associating these two investigations and pulmonary scintigraphy reduces the number of diagnostic angiographies by 30 to 50% according to whether D-dimer and ultrasonography are performed before or after scintigraphy respectively. More extensive use of D-dimer in clinical practice requires more rapid and equally reliable unitary tests as the ELISA.

Antifibrinolytic Agents↗
PubMed1994

Applicability of decision analysis to everyday clinical practice: a controlled feasibility trial.

OBJECTIVE: To determine whether decision analysis is applicable to routine management of suspected pulmonary embolism in an emergency care setting. DESIGN: Controlled feasibility trial. SETTING: Emergency center of a university hospital. PATIENTS: Outpatients (n = 84) admitted with clinical and scintigraphic evidence of pulmonary embolism. INTERVENTIONS: Patients were treated either with the usual clinical work-up for pulmonary embolism (control group) or using a decision analysis model with three options: no action: angiography followed by treatment if positive; treatment without angiography. RESULTS: All six senior residents in the decision analysis group agreed to fully participate for the 16 months of the study. Summarizing the decision analysis model in a graph was critical to obtain acceptance from all the physicians. Decision analysis (n = 43) and control (n = 41) patients underwent similar numbers of angiographies. However, angiographies for patients who had intermediate clinical probabilities of pulmonary embolism, between 25 and 75%, were more frequent in the decision analysis group (9/13 = 69%) than in the control group (7/20 = 35%). Agreement between clinical probability and lung-scan result was stronger in the decision analysis group. CONCLUSIONS: Decision analysis was successfully used to manage all patients suspected of having pulmonary embolism admitted to an emergency center during the 16-month trial. There was no insuperable obstacle to acceptance of clinical decision analysis by the physicians. Decision analysis may have resulted in a better discrimination between low and intermediate clinical probabilities of pulmonary embolism.

Adult↗
PubMed1994

Contribution of D-dimer plasma measurement and lower-limb venous ultrasound to the diagnosis of pulmonary embolism: a decision analysis model.

The Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study has shown that clinical evaluation and lung scanning may substantiate or exclude pulmonary embolism with reasonable probability in approximately half of the patients in whom it is suspected; for the remainder, pulmonary angiography is considered the gold standard diagnostic test. We performed a decision analysis to assess the potential of two noninvasive tests, D-dimer plasma measurement and lower-limb B-mode venous ultrasound, for reducing the number of pulmonary angiograms necessary to diagnose pulmonary embolism. Our decision model addresses hypothetical patients in the emergency ward with suspected pulmonary embolism and abnormal lung scan results. Results show that D-dimer measurements of less than 500 micrograms/L could be used reliably to exclude pulmonary embolism in patients with an abnormal but not high-probability (inconclusive) lung scan. D-dimer measurements of greater than 500 micrograms/L have no positive predictive value for pulmonary embolism and should be followed by ultrasound, which may replace pulmonary angiography when it discloses deep venous thrombosis. Pulmonary angiography should be performed when ultrasound is negative because of its presumably low sensitivity for deep venous thrombosis in patients with pulmonary embolism. A D-dimer measurement of less than 500 mu/L does not exclude pulmonary embolism in patients with a high clinical suspicion of pulmonary embolism. On the basis of the results of the PIOPED study, we calculated that the combination of D-dimer measurement and ultrasound might reduce the requirement for pulmonary angiography by one third among patients with inconclusive scan results and intermediate clinical probability of pulmonary embolism.

Angiography↗
PubMed1994

D-dimer determination to exclude pulmonary embolism: a two-step approach using latex assay as a screening tool.

D-dimer (DD), when measured by a quantitative enzyme-linked immunosorbent assay (ELISA), is a valuable test to exclude venous thromboembolism (VTE). However, DD ELISA technique is not appropriate for emergency use and the available agglutination latex assays are not sensitive enough to be used as an alternative to rule out the diagnosis of VTE. Latex assays could still be used as screening tests. We tested this hypothesis by comparing DD levels measured by ELISA and latex assays in 334 patients suspected of pulmonary embolism. All but one patient with a positive (DD > or = 500 ng/ml) latex assay had DD levels higher than 500 ng/ml with the ELISA assay. Accordingly, ELISA technique could be restricted to patients with a negative result in latex assay. This two-step approach would have spared about 50% of ELISA in our cohort. In conclusion, our data indicate that a latex test can be used as a first diagnostic step to rule out pulmonary embolism provided a negative result is confirmed by ELISA and the performance of the latex assay used has been assessed properly.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Plasma measurement of D-dimer as diagnostic aid in suspected venous thromboembolism: an overview.

This paper reviews the published experience with plasma measurement of D-dimer (DD), a specific degradation product of crosslinked fibrin, in the diagnostic approach of venous thromboembolism (VTE). Pooling 11 studies (with weighting of the figures according to sample size) with a total of 1337 patients clinically suspected of deep venous thrombosis (DVT) (prevalence of DVT 35%) disclosed an average weighted sensitivity of 96.8% (95% CI: 95.2-98.4) and specificity of 35.2% (95% CI: 32.0-38.4) for the presence of DVT when the ELISA technique was used. In 908 patients suspected of pulmonary embolism (PE) from 9 trials (prevalence of PE 38%), the ELISA technique was associated with a weighted sensitivity of 96.8% (95% CI: 95.0-98.6) and specificity of 45.1% (95% CI: 40.8-49.4) for the disease. Figures obtained with latex assays were definitely lower, precluding their use in the diagnostic approach of VTE. These results show that a low concentration of plasma DD measured by the ELISA technique (usually less than 500 micrograms/l) might be used to rule out VTE in clinically suspected patients. Increased plasma concentrations are of no utility because of the low specificity of this test result. The clinical usefulness of the DD ELISA test should now be assessed in management trials under routine conditions, in the frame of clinical decision-making diagnostic processes. Lastly, the promising data obtained in a small number of asymptomatic, postoperative patients at risk of VTE deserve confirmation before the test can be recommended for initial screening in thrombo-prophylactic trials.

Biomarkers↗
PubMed1991

Very severe self-poisoning lithium carbonate intoxication causing a myocardial infarction.

A case of severe lithium carbonate self-poisoning is described, presenting with a very high serum lithium level (14.6 mmol/L) on admission. Lengthy and repeated hemodialyses were required to lower lithemia to nontoxic ranges. As is usually reported, our patient had prolonged neurologic manifestations (coma, hyperreflexia, fluctuating focal signs) and developed hypotension, cardiovascular collapse, nephrogenic diabetes insipidus, and diarrhea. Other less common features were the occurrence of acute myocardial infarction without coronary artery lesions and thrombocytopenia. The possible pathogenic mechanisms are discussed. Hemodialysis and supportive intensive care treatment are commented upon. The final outcome was favorable, and the patient recovered completely.

Bipolar Disorder↗
PubMedDate not supplied

[Value of D-dimers in diagnosis of acute pulmonary embolism].

FIBRIN BREAKDOWN PRODUCTS: D-dimers are protein substances resulting from the action of 3 enzymes, thrombin, factor XIII and plasmin, on the fibrinogen molecules. In the case of thrombosis, all these enzymatic reactions are activated, explaining the increase in D-dimer levels induced. The notion of a threshold is only significant for a given test; the 500 micrograms/L threshold is widely used for tests relying on ELISA methods (enzyme-linked immunosorbent assay). FROM A TECHNICAL POINT OF VIEW: The use of D-dimer ELISA in excluding pulmonary embolism is now well established. New quantitative tests with latex, based on a turbidimetric method, also appear interesting in this context. The latter is reliable, rapid, inexpensive, remarkably sensitive (97 to 100%) and widely available. INTEREST: Performed in the initial stages of diagnosis in an out-patient population with a 20-25% prevalence of the disease, it excludes the diagnosis in around 30% of patients. Decisional analysis models have shown that this method is economically profitable. However, in elderly hospitalised patients, its clinical utility is lesser because of its low specificity in this population. The association of high clinical probability of pulmonary embolism and normal D-dimer leves is rare and has a weaker negative predictive value, even when the ELISA technique is used.

Acute Disease↗
PubMedDate not supplied

Noninvasive diagnosis of pulmonary embolism.

BACKGROUND AND OBJECTIVE: Pulmonary embolism (PE), with an incidence of 23 per 100,000 patients per year, is a frequent clinical problem, responsible for 200,000 deaths each year in the United States. Pulmonary angiography, the gold standard for diagnosing PE, is invasive, costly and not universally available. Moreover, PE is confirmed in only approximately 30% of patients in whom it is suspected, rendering noninvasive screening tests necessary. Several strategies have been recently proposed to reduce the need for pulmonary angiography in the diagnostic workup of pulmonary embolism. The objective of this article is to analyze the individual performance of the new diagnostic instruments and their combination in rational diagnostic strategies. METHODS: The author has been working in this field and has contributed original papers on diagnosis of pulmonary embolism and cost-effectiveness of noninvasive diagnostic tests. In addition, the material examined in this article includes articles published in the journals covered by the Science Citation Index and Medline. RESULTS: Several strategies have been recently proposed to reduce the need for pulmonary angiography in the diagnostic workup of pulmonary embolism. The PIOPED study has established the value of ventilation-perfusion lung scan, a normal perfusion lung scan virtually ruling out PE, whereas a high probability lung scan is considered diagnostic in face of reasonable clinical suspicion. All other lung scan results are nondiagnostic. However, clinical evaluation, although insufficiently accurate to yield a definitive diagnosis, is probably reliable enough to be used for estimating pretest probability of PE. The combination of a low clinical probability of PE and a so-called low probability lung scan yields a very low posttest probability of PE, thus foregoing the need for pulmonary angiography. Other useful instrument in patients with nondiagnostic scans is plasma D-dimer (DD) measurement (ELISA assay), which when under a cutoff value of 500 micrograms/L potentially exclude PE, due to high sensitivity (97%). Conversely, venous compression ultrasonography of the lower limbs (US) is highly specific (98%) for deep vein thrombosis (DVT), and disclosing a DVT warrants anticoagulant treatment without resorting to angiography. The potential role of echocardiography is also discussed. The rational sequence of noninvasive tests is currently under discussion. Performing D-dimer and US before lung scan may be the most cost-effective strategy, pulmonary angiography being performed only in case of an inconclusive noninvasive workup. INTERPRETATION AND CONCLUSIONS: Even though PE remains a difficult diagnostic challenge, the availability of novel noninvasive tests (plasma D-dimer and ultrasonography of the lower limbs) and the rehabilitation of clinical assessment allow a more rational and sparse prescription of pulmonary angiography. More work needs to be done to assess test performances and refine diagnostic strategies in distinct patient subgroups, particularly those hospitalized. Screening patients with plasma D-dimer and ultrasonography of the lower limbs may be the most cost-effective strategy, at least in outpatients.

Algorithms↗