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

Abstract

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. 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. 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. 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.