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A Perrier

Publications and source records attributed to A Perrier.

At least 37 records · Page 2Linked to original sources
PubMed2001

Cost-effective diagnosis of deep vein thrombosis and pulmonary embolism.

Suspected acute venous thromboembolism is a frequent and challenging clinical problem. Phlebography and pulmonary angiography are costly and invasive and, hence, ill-suited for diagnosing a disease present in only 20% of patients in whom it is suspected. Novel noninvasive instruments, such as plasma D-dimer measurement, lower limb compression ultrasonography and helical CT scan are important breakthroughs in the management of patients with suspected venous thromboembolism. However, none of these instruments is ideal, and they must be combined in rational and cost-effective diagnostic algorithms including clinical assessment, which is increasingly standardized. Such strategies must be validated in management studies, in which patients without venous thromboembolism are not treated and followed up during 3 months. Suspected massive pulmonary embolism is a distinct clinical situation requiring a specific diagnostic approach, in which echocardiography plays a major role. This paper reviews the performance of clinical evaluation and diagnostic tests for venous thromboembolism, and recently validated diagnostic schemes.

Algorithms↗
PubMed2001

Prediction of pulmonary embolism extent by clinical findings, D-dimer level and deep vein thrombosis shown by ultrasound.

Pulmonary embolism (PE) may encompass a wide spectrum of severity. To determine whether clinical findings, D-dimer (DD) concentration, and deep vein thrombosis (DVT) shown by lower-limb venous compression ultrasonography (US) might predict the scintigraphic extent of PE, we studied 104 hemodynamically stable consecutive outpatients with acute PE diagnosed by a high-probability ventilation-perfusion lung scan. Scintigraphic extent of PE was classified into three categories: perfusion defects corresponding to <30%, 30-50%, or >50% of the total lung area. Median respiratory and heart rates were found to be significantly related to the extent of PE. Higher median alveolar-arterial oxygen difference values were observed as the proportion of lung perfusion defects increased (>50% vs. <30%, 6.3 vs. 3.6 kPa, P <.0001). Median plasma DD concentration was 7950 microg/L in patients with >50% perfusion defects compared to 2731 microg/L in those with <30% defects (P = .0001). DD levels above 4000 microg/L were associated to more extensive perfusion defects (>50% vs. <30% defects, OR 30; 95% CI 5.8-155). Finally, a proximal DVT was more likely among patients with larger perfusion defects (>50% vs. <30% defects, OR 4.5; 95% CI 1.5-13.6). In conclusion, clinical signs such as tachypnea and tachycardia, alveolar-arterial oxygen difference, plasma DD concentration, and presence of DVT on US are predictors of a larger PE, as assessed by the extent of perfusion defects on high probability lung scans.

Adult↗
PubMed2000

Effects of age on the performance of common diagnostic tests for pulmonary embolism.

PURPOSE: The diagnosis of pulmonary embolism in the elderly is often difficult because of comorbid medical conditions, and perhaps also because diagnostic tests have a lower yield. We analyzed the diagnostic performance of common diagnostic tests for pulmonary embolism in different age groups. METHODS: We analyzed data from two large studies that enrolled 1,029 consecutive patients presenting to the emergency department with clinically suspected pulmonary embolism. The clinical probability of pulmonary embolism (high [>/=80%], intermediate, or low [</=20%]) was estimated by the treating physician. All patients underwent a sequential diagnostic protocol, including ventilation-perfusion lung scan, measurement of plasma D-dimer level, lower limb venous compression ultrasonography, and pulmonary angiography if the noninvasive work-up was inconclusive. RESULTS: The prevalence of pulmonary embolism increased progressively, from 12% in patients <40 years of age to 44% in those >/=80 years of age. The positive predictive value of a high clinical probability of pulmonary embolism was greater in the elderly (71% to 78% in those >/=60 years old versus 40% to 64% in those </=59 years old). The sensitivity of D-dimer testing was 100% in all age groups, but its specificity decreased markedly with age, from 67% in those </=40 years old to 10% in those >/=80 years old. The diagnostic yield of lower limb compression ultrasonography was greater in the elderly. The proportion of lung scans that were diagnostic (normal, near-normal, or high probability) decreased from 68% to 42% with increasing age. CONCLUSIONS: Age affects the performance of common diagnostic tests for pulmonary embolism and should be kept in mind when evaluating patients suspected of having this condition.

Adult↗
PubMed2000

Using clinical evaluation and lung scan to rule out suspected pulmonary embolism: Is it a valid option in patients with normal results of lower-limb venous compression ultrasonography?

BACKGROUND: In patients with a low clinical probability of pulmonary embolism (PE) and a nondiagnostic lung scan, the prevalence of PE is theoretically very low. We assessed the safety and usefulness of this association for ruling out PE. METHODS: We analyzed data from 2 consecutive cohort management studies performed in 2 university hospitals (Geneva University Hospital, Geneva, Switzerland, and Hospital Saint-Luc, Montreal, Quebec), which enrolled 1034 consecutive patients who came to the emergency department with clinically suspected PE. All patients were submitted to a sequential diagnostic protocol of lung scan, D-dimer testing, lower-limb venous compression ultrasonography (US), and pulmonary angiography in case of inconclusive results of noninvasive workup. RESULTS: The prevalence of PE was 27.6%. Empirical assessment was accurate for identifying patients with a low likelihood of PE (8.2% prevalence of PE in the low clinical probability category). One hundred eighty patients had a low clinical probability of PE and a nondiagnostic lung scan. Among these patients, US showed deep vein thrombosis in 5. Hence, PE could be ruled out by a low clinical probability, a nondiagnostic lung scan, and a normal US in 175 patients (21.5%). The 3-month thromboembolic risk in these patients was low (1.7%; 95% confidence interval, 0.4%-4.9%). CONCLUSIONS: Anticoagulant treatment could be safely withheld in patients with a low clinical probability of PE and a nondiagnostic lung scan, provided that the US is normal. This combination of findings avoided pulmonary angiography in 21.5% of patients with suspected PE in this series.

Adult↗
PubMed2000

Diagnosis of acute pulmonary embolism: an update.

Considerable progress has been made in pulmonary embolism diagnosis during the last ten years. New diagnostic instruments such as plasma D-dimer measurement and lower venous compression ultrasonography have been developed. Clinical evaluation of the likelihood of pulmonary embolism has been rehabilitated and proven accurate and valid. The interpretation of lung scan results has become more simple and clear to clinicians. Finally, two diagnostic strategies have been validated in large scale outcome studies. Both rely on a sequential combination of the above mentioned instruments and have been able to safely manage more than 90% of patients without a pulmonary angiogram. The 3-month venous thromboembolic risk in patients without pulmonary embolism and, hence, not anticoagulated was less than 1% in both studies. In the absence of a formal comparison of their respective cost-effectiveness, choosing between these strategies may rest on local preferences or logistics. Finally, spiral CT scan is highly promising and may considerably modify the diagnostic workup of pulmonary embolism in the near future. However, it is insufficiently validated and its position in a rational algorithm for diagnosing pulmonary embolism is not yet defined.

Acute Disease↗
PubMed2000

Prevalence of factor V Leiden and prothrombin G20210A mutations in unselected patients with venous thromboembolism.

We determined the prevalence of factor V Leiden and of prothrombin G20210A mutations in a cohort of unselected outpatients (n = 748) referred for suspected deep vein thrombosis (DVT) and/or pulmonary embolism (PE) and a pooled analysis of similar studies was also performed. Based on the clinical presentation, the prevalence of factor V Leiden was 15.7% in the 83 patients with DVT and 14.1% in the 99 patients with PE compared with 5.3% in patients without DVT and/or PE (control group). The prevalence of the prothrombin G20210A mutation did not differ among the three groups (3.9% for controls, 4. 8% for DVT and 3.9% for PE patients). We then divided the 99 patients with PE by separately analysing those with PE but without DVT (n = 57) and those with PE and DVT (n = 42). Compared with the control group, the prevalence of factor V Leiden was 10.5%, odds ratio (OR) 2.10 [95% confidence interval (95% CI) 0.68-5.45] in patients with primary PE and 19.1%, OR 4.20 (95% CI 1.54-10.30) in patients with DVT and PE. For the prothrombin G20210A mutation, no statistically significant differences were found between the control group and the three other groups. In conclusion, our data and the pooled analysis indicate that patients with primary PE are less often affected by the factor V Leiden mutation. No statistically significant differences were observed between patients and controls for the prothrombin G20210A mutation.

Adult↗
PubMed2000

Clinical assessment of suspected deep vein thrombosis: comparison between a score and empirical assessment.

OBJECTIVES: To assess the accuracy and agreement of two methods of clinical evaluation: a formal score based on a number of items of fixed value (the so-called Wells' score), and an empirical assessment based on a predefined list of items that can be weighted individually. Clinical probability is essential to manage suspected deep vein thrombosis (DVT) and should be assessed before any diagnostic test. DESIGN: An open, nonrandomised, one-centre study. SETTING: One centre in Switzerland (a university hospital delivering primary-tertiary care). SUBJECTS: Two hundred and seventy outpatients with a prevalence of DVT of 21.1% (final diagnosis), out of an initial population of 328 patients, of which 52 had to be excluded because of a history of DVT (score not applicable) or because of insufficient clinical information (n = 6). RESULTS: Agreement between the two assessment tools was poor (kappa value of 0.32), but accuracy was excellent, with a prevalence of DVT of 1.3%, 18.1%, and 100% (empirical assessment), and 3.2%, 19.4%, and 73.9% (Wells' score), for a low, intermediate or high clinical probability estimate, respectively. The main differences between the two methods were that (i) the empirical method performed slightly better in categorizing patients in the high probability class, and (ii) Wells' score categorized more patients in the low probability class. When applied to two validated diagnostic strategies, the empirical assessment required slightly fewer phlebograms in both strategies, and Wells' score required fewer repeat ultrasonograms (in the strategy that requires this procedure). CONCLUSIONS: Clinical probability assessment can be done with a similar accuracy either empirically or using a score. Institutions should incorporate clinical probability assessment with either method depending upon their diagnostic strategy for suspected DVT.

Adult↗
PubMed2000

Risk of major bleeding in unselected patients with venous thromboembolism.

PURPOSE: To evaluate the risk of major bleeding in unselected patients given anticoagulant treatment (heparin overlapped and followed by oral anticoagulants) because of deep vein thrombosis (DVT) or pulmonary embolism (PE). SUBJECTS AND METHODS: We screened the database of 1590 outpatients suspected of DVT and PE in prospective diagnostic studies conducted in Geneva between 1992 and 1998. RESULTS: Four hundred and eleven of 1590 patients (26%) were anticoagulated for confirmed venous thromboembolism (PE, 300; DVT, 111). One patient was excluded because of concomitant thrombolytic therapy. Five (1.2%; 95% confidence interval, 0.4-2.8) of the remaining 410 patients experienced a major hemorrhagic event during the 3-month follow-up, including two fatal events. All bleedings occurred during the first month of therapy (heparin, two; oral anticoagulants, two; combined treatment, one) and the median age of the patients who bled was 80 years. At least one serious comorbid condition associated with higher bleeding risk was present in four patients and, in one case, the bleeding was clearly related to an excessive intensity of anticoagulation. CONCLUSION: The rate of bleeding events in this population of unselected outpatients is similar to that reported in controlled therapeutic trials. The hemorrhagic events occurred early in the course of anticoagulant therapy and concerned old patients mostly affected by at least one comorbid condition. Particular care should be used to avoid the risk of overtreatment.

Aged↗
PubMed2000

Predicting adverse outcome in patients with acute pulmonary embolism: a risk score.

Reliable prediction of adverse outcomes in acute pulmonary embolism may help choose between in-hospital and ambulatory treatment. We aimed to identify predictors of adverse events in patients with pulmonary embolism and to generate a simple risk score for use in clinical settings. We prospectively followed 296 consecutive patients with pulmonary embolism admitted through the emergency ward. Logistic regression was used to predict death, recurrent thromboembolic event, or major bleeding at 3 months. Thirty patients (10.1%) had one or more adverse events during the 3-month follow-up period: 25 patients (8.4%) died, thromboembolic events recurred in 10 patients (3.4%), and major bleeding occurred in 5 patients (1.7%). Factors associated with an adverse outcome in multivariate analysis were cancer, heart failure, previous deep vein thrombosis, systolic blood pressure <100 mmHg, arterial PaO2 <8 kPa, and presence of deep vein thrombosis on ultrasound. A risk score was calculated by adding 2 points for cancer and hypotension, and 1 point each for the other predictors. A score of 2 best identified patients at risk of an adverse outcome in a receiver operating characteristic curve analysis. Of 180 low-risk patients (67.2%) (score < or =2), only 4 experienced an adverse outcome (2.2%), compared to 23 (26.1%) of 88 high-risk patients (score > or =3). A simple risk score based on easily available variables can accurately identify patients with pulmonary embolism at low risk of an adverse outcome. Such a score may be useful for selecting patients with pulmonary embolism eligible for outpatient care.

Adult↗
PubMed1999

Evidence-based medicine and critical care.

Applying the best available scientific evidence to selecting the most appropriate action for the care of individual patients is not a novel concept. Nevertheless, in these times of exponential growth in medical literature, heavy time constraints on clinicians and increasing health care costs, this approach needed to be reemphasised. The promoters of evidence-based medicine have contributed significantly to this task, by making explicit the steps from the search for the best evidence (randomised controlled trials and meta-analyses) to its application to clinical practice. Moreover, they have developed and made available several invaluable tools for critical appraisal of the medical literature. To illustrate the usefulness of evidence-based medicine, we applied this approach to two clinical situations: (1) the decision whether to use NPPV instead of conventional ventilation in a patient with acute respiratory failure due to severe pneumonia; and (2) whether to administer albumin to critically ill patients with hypovolaemia, burns or hypoalbuninaemia. Finally, the limitations of evidence-based medicine and its main instruments, i.e. randomised controlled trials and meta-analyses, are briefly discussed.

Aged↗
PubMed1999

Non-invasive diagnosis of venous thromboembolism in outpatients.

BACKGROUND: We designed a simple and integrated diagnostic algorithm for acute venous thromboembolism based on clinical probability assessment of deep-vein thrombosis (DVT) or pulmonary embolism (PE), plasma D-dimer measurement, lower-limb venous compression ultrasonography, and lung scan to reduce the need for phlebography and pulmonary angiography. METHODS: 918 consecutive patients presenting at the emergency ward of the Geneva University Hospital, Geneva, Switzerland, and Hôpital Saint-Luc, Montreal, Canada, with clinically suspected venous thromboembolism were entered into a sequential diagnostic protocol. Patients in whom venous thromboembolism was deemed absent were not given anticoagulants and were followed up for 3 months. FINDINGS: A normal D-dimer concentration (<500 microg/L by a rapid ELISA) ruled out venous thromboembolism in 286 (31%) members of the study cohort, whereas DVT by ultrasonography established the diagnosis in 157 (17%). Lung scan was diagnostic in 80 (9%) of the remaining patients. Venous thromboembolism was also deemed absent in patients with low to intermediate clinical probability of DVT and a normal venous ultrasonography (236 [26%] patients), and in patients with a low clinical probability of PE and a non-diagnostic result on lung scan (107 [12%] patients). Pulmonary angiography and phlebography were done in only 50 (5%) and 2 (<1%) of the patients, respectively. Hence, a non-invasive diagnosis was possible in 866 (94%) members of the entire cohort. The 3-month thromboembolic risk in patients not given anticoagulants, based on the results of the diagnostic protocol, was 1.8% (95% CI 0.9-3.1). INTERPRETATION: A diagnostic strategy combining clinical assessment, D-dimer, ultrasonography, and lung scan gave a non-invasive diagnosis in the vast majority of outpatients with suspected venous thromboembolism, and appeared to be safe.

Acute Disease↗
PubMed1999

Contribution of noninvasive evaluation to the diagnosis of pulmonary embolism in hospitalized patients.

The effectiveness of new diagnostic tools for suspected pulmonary embolism (PE), such as clinical probability assessment, plasma D-dimer (DD) measurement and lower limb venous compression ultrasonography (US), has not been specifically studied in patients with a suspected PE occurring during hospital stay. This study applied a sequential, decision analysis-based strategy adding these instruments to a ventilation/perfusion lung scan in a cohort of 114 consecutive inpatients clinically suspected of PE in order to establish in how many patients a pulmonary angiogram could thereby be avoided. A definitive diagnosis could be established by the noninvasive protocol in 61% of these patients: normal/near-normal lung scan, 14%; high probability lung scan, 19%; clinical probability combined with lung scan result, 18%; and US, 8%. Specificity of DD was only 7% and contributed to the exclusion of PE in only two patients. Pulmonary angiography was required in 39% of patients. The 3-month thromboembolic risk in patients in whom PE was excluded by the diagnostic process was 0% (95% confidence interval 0-4.9%). In conclusion, a noninvasive work-up for suspected pulmonary embolism is effective in hospitalized patients, allowing to forego angiography in 61% of them, and it appears to be safe, although this should be further investigated. In contrast to outpatients, D-dimer measurement appears to be useless in hospitalized patients.

Adult↗
PubMed1999

Performances of the fibrin monomer test for the exclusion of pulmonary embolism in symptomatic outpatients.

Many studies have shown that D-dimer determinations can be used for the exclusion of venous thromboembolism in symptomatic outpatients, depending however on the method of D-dimer measurement. Another related assay, the Fibrin Monomer test which measures soluble fibrin levels in plasma by ELISA, is now available. We have evaluated the performances of this assay for the exclusion of pulmonary embolism (PE) in 426 consecutive outpatients presenting at the emergency ward of our institution. Diagnosis of PE was made by D-dimer measurement, compression ultrasonography, lung scintigraphy, venography and pulmonary angiography. With a cut-off of 3 microg/ml. the sensitivity and the negative predictive value were both 100% (95% CI: 97.1-100 and 96.3-100 respectively) and the specificity 33% (95 % CI: 25.7-38.1). With 4 microg/ml, the corresponding figures were 98.4 (95% CI: 94.4-99.8), 98.3 (95% CI: 94.1-99.8) and 39% (95% CI: 33.6-44.7) respectively. The prevalence of PE was 30%, the exclusion rates were 23 and 27% for either cut-off. When compared with a reference D-dimer assay (Asserachrom D-Di), a good correlation was observed. In conclusion, this is the first study suggesting the interest of this Fibrin Monomer test to rule out PE; these results, however, need to be confirmed by other studies.

Emergencies↗