A simple diagnostic strategy in hospitalized patients with clinically suspected pulmonary embolism.

OBJECTIVES: Diagnostic strategies in patients with suspected pulmonary embolism have been extensively studied in outpatients; their value in hospitalized patients has not been well established. Our aim was to determine the safety and clinical utility of a simple diagnostic strategy in hospitalized patients with suspected pulmonary embolism. DESIGN: Prospective management study. SETTING: Twelve teaching hospitals (five academic, seven general hospitals). SUBJECT: A total of 605 hospitalized patients with clinically suspected pulmonary embolism. All patients completed the study. INTERVENTIONS: First the clinical decision rule (CDR)-score was calculated. An unlikely CDR-score in combination with a normal D-dimer excluded pulmonary embolism. All other patients underwent helical computed tomography (CT). CT either diagnosed or excluded pulmonary embolism, in which case anticoagulants were started or withheld. All patients were instructed to report symptoms of venous thrombosis. Objective tests were performed to confirm venous thromboembolism. The primary outcome was the incidence of symptomatic venous thrombosis during 3-month follow-up. RESULTS: The combination of an unlikely CDR-score and a normal D-dimer excluded pulmonary embolism in 60 patients (10% of all patients); no venous thromboembolic event occurred during follow-up (0%; 95% CI 0-6.7%). CT excluded pulmonary embolism in 380 patients; during follow-up venous thromboembolism occurred in five patients (1.4%; 95% CI 0.4-3.1%). CONCLUSIONS: An unlikely CDR-score in combination with a normal D-dimer appears to exclude pulmonary embolism safely in hospitalized patients. Before clinical implementation it is important this safety is confirmed by others. CT testing was obviated in only 10% of patients. CT can safely exclude pulmonary embolism in hospitalized patients.

Accuracy of clinical decision rule, D-dimer and spiral computed tomography in patients with malignancy, previous venous thromboembolism, COPD or heart failure and in older patients with suspected pulmonary embolism.

BACKGROUND: The diagnostic work-up of patients with suspected pulmonary embolism (PE) has been optimized and simplified by the use of clinical decision rules (CDR), D-dimer (DD) testing and spiral computed tomography (s-CT). Whether this strategy is equally safe and efficient in specific subgroups of patients is evaluated in this study. METHODS: A diagnostic strategy including a CDR, DD test and s-CT was evaluated in patients with malignancy, previous venous thromboembolism (VTE), chronic obstructive pulmonary disease or heart failure and in older patients. PE was ruled out by either an unlikely CDR and a normal DD or a s-CT negative for PE. The safety of these tests was assessed by the 3-month incidence rate of symptomatic VTE in those without PE at baseline. The efficiency was evaluated by calculating the numbers needed to test for the different subgroups. RESULTS: The venous thromboembolic incidence rate after the combination of an unlikely CDR and a normal DD varied from 0% (95% CI: 0-7.9%) in the 482 patients older than 75 years of age to 2% (95% CI: 0.05-10.9%) in the 474 patients with a malignancy. For s-CT these incidences varied from 0.3% to 1.8%. The number needed to test in order to rule out one patient from PE with the studied strategy was highest in cancer patients and in the elderly patients (approximately 10). CONCLUSION: It appears to be safe to rule out PE by either the combination of an unlikely CDR and a normal DD or by a negative s-CT in various subgroups of patients with suspected PE. However, the clinical usefulness of the CDR in combination with the DD as the initial step in the diagnostic process varied among these patient groups.

Convergent synthesis, chiral HPLC, and vitamin D receptor affinity of analogs of 1,25-dihydroxycholecalciferol.

A series of analogs of 1,25-dihydroxycholecalciferol was obtained with an additional chiral center at the terminus of the aliphatic side chain (C-25). The analogs were obtained from (+)-(R)- and (-)-(S)-2-methylglycidols, by opening of the oxirane ring with the carbanions derived from vitamin D C23a,24- or C22-sulfones. The diastereomeric purity of the analogs was determined by high-performance liquid chromatography on a chiral stationary phase. The binding affinity of analogs for the calf thymus intracellular vitamin D receptor (VDR) was two orders of magnitude lower than that of the lead compound of this group, 24a,24b-dihomo-1,25-dihydroxycholecalciferol, and it was comparable to the affinity of analogs of 24-nor-1,25-dihydroxycholecalciferol. However, a twofold difference was observed for analogs diastereomeric at C-25 in their affinity for VDR. The diastereodifferentiation of the binding affinity was found to be specific for vitamin D vicinal 25,26-diols as it disappears for analogs where 26-hydroxyl, neighboring the C-25 chiral center, is replaced with methyl.

Synthesis and in vitro evaluation of side chain-unsaturated analogs of 24a,24b-dihomo-1,25-dihydroxycholecalciferol.

A synthesis and an in vitro evaluation of side chain-unsaturated analogs 3 and 4 of 24a, 24b-dihomo-1,25-dihydroxycholecalciferol (1) are described, Novel C23a, 24-vitamin D synthons (sulfone 10 and aldehyde 11) were used for the synthesis of analog 4 and for the efficient preparation of the parent compound 1. The synthetic approach developed allows the use of easily available side chain fragments, such as oxirane 12 or Wittig reagent 15 for the preparation of compound 1 and analog 4, respectively. Introduction of a 24aE double bond results in a selective, 1000-fold increase in the binding affinity of analog 4 for the vitamin D receptor, compared to the affinity of 1, whereas the affinity of 4 for the vitamin D-binding protein and the activity in stimulating the differentiation of human promyelocytic leukemia HL-60 cells remained largely unchanged.