Can a Trained Radiology Technician Do Arterial Obstruction Quantification in Patients With Acute Pulmonary Embolism?

CT Pulmonary Angiography for Risk Stratification of Patients with Nonmassive Acute Pulmonary Embolism

Purpose

To investigate the prognostic value of an integrative approach combining clinical variables and the Qanadli CT obstruction index (CTOI) in patients with nonmassive acute pulmonary embolism (PE).

Materials and Methods

This retrospective study included 705 consecutive patients (mean age, 63 years; range, 18-95 years) with proven PE. Clot burden was quantified using the CTOI, which reflects the ratio of fully or partially obstructed pulmonary arteries to normal arteries. Patients were subdivided into two groups according to the presence (group A) or absence (group B) of preexisting cardiopulmonary disease. Thirty-day and 3-month mortality was evaluated. CTOI thresholds of 20% and 40% were used to stratify patients regarding outcome (low, intermediate, and high risk). The predictive value of CTOI was assessed through logistic regression analysis.

Results

Analysis included 690 patients (mean age, 63.3 years ± 18 [standard deviation]) with complete follow-up data: 247 (36%) in group A and 443 (64%) in group B. The mean CTOI was 23% ± 19, 30-day mortality was 9.7%, and 3-month mortality was 11.6%. Three-month mortality was higher in group A than in group B (17.8% and 8.1%, respectively; P = .001). Within group B, CTOI predicted outcome and allowed stratification: significantly higher mortality with CTOI greater than 40% (P < .001) and lower mortality with CTOI less than 20% (P = .05). CTOI did not predict outcome in group A. Age was an independent mortality risk factor (P ≤ .04).

Conclusion

CTOI predicted outcome in this cohort of patients with PE and no cardiopulmonary disease, and it may provide a simple single-examination-based approach for risk stratification in this subset of patients.© RSNA, 2020See also the commentary by Kay and Abbara in this issue.

Effect of platelet inhibitors on thrombus burden in patients with acute pulmonary embolism

Venous thromboembolism (VTE) whether provoked or not can be life-threatening due to an acute increase in load on the right ventricle (RV) from obstruction of the pulmonary artery (PA). Treatment for and prevention of VTE involves anti-thrombotic agents; more specifically, medications targeting the anticoagulation cascade. In spite of the widespread acceptance of anticoagulants in the treatment of VTE, there appears to be an ongoing belief that platelet reactivity contributes to thrombus burden in patients with acute pulmonary embolism (PE). This investigation of 398 patients presenting with acute PE evaluated whether anti-platelet medication use, which consisted mostly of aspirin therapy, at the time of presentation, affects PA thrombus burden, RV load, or short-term patient outcomes. We conclude that platelets may have been erroneously incriminated as direct thrombotic mediators in patients with acute PE since aspirin neither decreased PA thrombus burden, nor did aspirin improve short-term mortality following acute PE.