Ventricular septum curvature ratio: a novel imaging marker to predict clinical deterioration in normotensive acute pulmonary embolism.

BACKGROUND: Identifying high-probability deterioration individuals at the time of admission remains a challenge in normotensive patients with acute pulmonary embolism (PE). Ventricular septum (VS) deviation, as observed on computed tomography pulmonary angiography (CTPA), has been associated with poor prognosis in acute PE patients. However, the quantitative relationship between the VS curvature ratio and clinical deterioration in normotensive acute PE patients has not been fully explored. This study aimed to investigate the role of the VS curvature ratio derived from CTPA as an image marker for deterioration in normotensive acute PE patients. METHODS: This prospective multicenter cohort study enrolled normotensive patients with acute PE across five centers in China between January 2021 and June 2024. The VS and left ventricle (LV) free-wall curvature radii were measured using CTPA, and the VS curvature ratio was calculated and categorized. The endpoint was the occurrence of clinical deterioration event within 30 days after admission. The relationship between the VS curvature ratio and deterioration was analyzed using hierarchical logistic regression. The efficacy of identifying deterioration was assessed using the area under the receiver operating characteristic curve (AUC). RESULTS: Of 3,310 patients, 272 (8.2%) experienced deterioration. In 3,030 patients from three centres, VS were categorized into four groups: VS bowing to the RV with its curvature ratio as < 1.60, 1.60-<1.90, ≥ 1.90, respectively; and the fourth group with VS straight or bowing to the LV. Using a VS curvature ratio < 1.60 as the reference, patients with higher VS curvature ratios had an increased risk of deterioration (odds ratio: 22.94 for ≥ 1.90 and 22.95 for VS straight & bowing to the LV, both p < 0.05). The VS curvature ratio demonstrated good discrimination for deterioration, with an AUC of 0.83 in the three local centers and 0.84 in the two non-local centers (280 patients). CONCLUSIONS: The VS curvature ratio, derived from CTPA images, is a promising image marker for predicting deterioration in normotensive acute PE patients. This study highlights the potential clinical impact of VS curvature ratio to identify normotensive PE patients at increased risk of deterioration and to adjust management strategies accordingly. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05098769, October 16,2021, retrospectively registered.