Assessment of Patterns of Potentially Unsafe Use of Zolpidem
Authors: Thomas J. Moore, Donald R. Mattison
Journal: JAMA Internal Medicine (2018)

SSPE detected only on multidetector CTPA may not be clinically significant.In contrast, den Exter and colleagues 7 found that in 116 patients with SSPE and 632 patients with proximal PE, recurrent VTE rates did not differ between the groups (3.6% vs 2.4%, respectively).This study, however, reported higher than expected mortality rates (10.3% in SSPE and 6.3% in proximal PE).On close examination, the patients included in the study had a high prevalence of comorbidities, particularly malignant neoplasm.In addition, many of the patients had concomitant DVT and would not have been candidates for clinical observation alone. 1A more contemporary systematic review and meta-analysis of patients with SSPE has been published. 8The authors included 14 studies comprising more than 15 000 patients.The pooled prevalence of SSPE was 4.6%.The frequency of bleeding in anticoagulated patients was 8.1% (95% CI, 2.8%-15.8%),although bleeding rates were not recorded for untreated patients.The frequency of recurrent venous thromboembolism was not different between treated and untreated patients (5.3%; 95% CI, 1.6%-10.9%vs 3.9%; 95% CI, 4.8%-13.4%)nor was there a difference in overall mortality (2.1%; 95% CI, 3.4%-5.2%vs 3.0%; 95% CI, 2.8%-8.6%). 8 There are no randomized clinical trials addressing this topic.Although a large prospective cohort study is currently ongoing in Canada and Europe (NCT01455818), it is still in the enrollment phase with results not expected for an additional 18 months (M.Carrier, MD, lead investigator, written communication, May 2018).Given the current body of evidence, authors of the most recent American College of Chest Physicians Antithrombotic Guidelines 9 suggested an individualized approach to patient management.The authors recommend first assessing the likelihood that the CTPA is a true positive result.Factors that favor a true positive result include a high-quality CTPA, multiple intraluminal filling defects, defects involving more proximal subsegmental vessels, defects seen on more than 1 image or projection, defects that are surrounded by contrast rather than appearing adherent to the vessel wall, symptomatic patient, high clinical pretest probability for acute PE, or an unexplained elevated D-dimer level.Plasma concentrations of D-dimer have been shown to correlate with clot burden. 2 In instances in which there is a high level of suspicion of a false-positive result, the high risk of bleeding should lead to the avoidance of anticoagulation.In patients believed to have a true, clinically relevant SSPE (without DVT, which would warrant treatment), the decision to anticoagulate should be based on an assessment of the patient's risk of recurrence, cardiopulmonary reserve, and risk of bleeding.In low-risk patients with adequate reserve, or in patients with high bleeding risk, clinical surveillance is favored.Factors that might lead to the decision to anticoagulate include the presence of active malignant neoplasm, idiopathic clot, marked symptoms, or patient preference.Although the majority of the cohort of patients that Raslan and colleagues 5 are reporting on predated the publication of the recent guidelines, their data nonetheless highlight the issue of overtreatment of SSPE and the potential harm associated with it.Pending future management trials, the clinical equipoise that practitioners face with SSPE should, at a minimum, mandate a conversation with the patient regarding the advantages and disadvantages of anticoagulation treatment in SSPE.