G E Raskob — Page 5 | Search PubMed

PubMed1983

Pulmonary angiography, ventilation lung scanning, and venography for clinically suspected pulmonary embolism with abnormal perfusion lung scan.

Inherent contradictions in current diagnostic recommendations for pulmonary embolism have created considerable confusion and controversy. To resolve these contradictions, we did a prospective study of ventilation-perfusion scanning, pulmonary angiography, and venography in consecutive patients with clinically suspected pulmonary embolism and abnormal perfusion scans. Ventilation scanning increased the probability of pulmonary embolism in patients with large perfusion defects and ventilation mismatch, but a ventilation-perfusion match was not helpful in ruling out pulmonary embolism. Small perfusion defects with mismatch had neither sufficiently high nor low probability to be of diagnostic value. The observed frequency of proximal vein thrombosis (19% to 51%) and its association with the range of ventilation-perfusion defects have important implications for management of pulmonary embolism. Pulmonary angiography is required in combination with venography in most patients with perfusion abnormalities because the probability of pulmonary embolism is neither sufficiently high nor low to confirm or exclude pulmonary embolism.

Adolescent↗

PubMedDate not supplied

Relation between the time to achieve the lower limit of the APTT therapeutic range and recurrent venous thromboembolism during heparin treatment for deep vein thrombosis.

BACKGROUND: Randomized trials have demonstrated the importance of achieving adequate heparinization early in the course of therapy. Recently, some authors reported a pooled analysis of selected studies in the literature that suggested that there is no convincing evidence that the risk of recurrent venous thromboembolism is critically dependent on achieving a therapeutic activated partial thromboplastin time result at 24 to 48 hours. METHODS: We provide the analyses of patient groups entered into our series of 3 consecutive double-blind randomized trials evaluating initial heparin therapy for proximal deep venous thrombosis. RESULTS: Logistic regression analysis of the patient groups receiving the less intense initial intravenous heparin dose of 30,000 U/24 h demonstrated that subtherapy for 24 hours predicted the onset of venous thromboembolic events. Failure to achieve a therapeutic activated partial thromboplastin time by 24 hours was associated with a 23.3% frequency of venous thromboembolism vs 4% to 6% for those whose activated partial thromboplastin time exceeded the therapeutic threshold by 24 hours (P=.02). Time-to-event analysis shows the increased frequency of recurrent venous thromboembolic events during the period of study in patients who were subtherapeutic for 24 hours compared with those who were therapeutic (P=.001). CONCLUSIONS: Our findings reaffirm the clinical importance of rapidly achieving therapeutic levels of heparin. Patients who failed to achieve the therapeutic threshold by 24 hours were at an increased risk of subsequent recurrent venous thromboembolism. These findings are independently supported by the results of a randomized trial comparing different intensities of initial heparin treatment by continuous infusion.

Anticoagulants↗