Clot Burden As a Predictor of Chronic Thromboembolic Pulmonary Hypertension After Acute Pulmonary Embolism: A Cohort Study

Abstract

Objective: A small percentage of acute pulmonary thromboembolisms (PTE) persist as chronic fibrin clots, potentially leading to chronic thromboembolic pulmonary hypertension (CTEPH). A scoring system for evaluating the burden of acute PTE based on computed tomography pulmonary angiogram (CTPA) findings was tested for its association with CTEPH within one year. Material and Methods: In this retrospective cohort of 475 patients with a definitive diagnosis of acute PTE, the Qanadli score (QS) was calculated on the initial CTPA. Through regular follow-up over 1 year, symptomatic patients underwent extensive evaluation. Results: Of the 475 patients enrolled in the study [age 58.3 ± 16.6, 195 (41.1%) female, QS: 13.01 ± 7.37/40], 321 patients completed the study. A total of 22 (6.8%) patients were definitively diagnosed with CTEPH. In univariate analysis, the initial QS was significantly higher in patients with subsequent CTEPH than in patients without (17 ± 5.6 vs. 13 ± 7.6, P = .009). QS was directly associated with CTEPH (odds ratio: 1.08, 95% confidence interval: 1.0-1.16, P = .042). The evolution of CTEPH in men could be predicted with a sensitivity of 100% and a specificity of 54% when a cut-off point of 14.5 (43.5%) was set for QS. The area under the receiver operating characteristic curve in this setting was 0.74 with a P -value of .032. Qanadli score failed to predict CTEPH in women. Conclusion: Scoring the clot burden in the pulmonary arteries through the Qanadli method can predict the evolution of CTEPH only in men 1 year after acute PTE. Women comprise most of the CTEPH patients. Thus, strict follow-up adherence seems to be even more important in women.