Six Radiologic Parameters May Predict CTEPH in Acute Pulmonary Embolism

Independent predictors of chronic thromboembolic pulmonary hypertension (CTEPH) as displayed on computed tomography pulmonary angiogram (CTPA) scans include intravascular webs, pulmonary artery retraction or dilatation, bronchial artery dilatation, right ventricular (RV) hypertrophy, and interventricular septum flattening. This finding may help improve diagnosis of CTEPH in patients with acute pulmonary embolism (PE). Results of the study were recently published in the Journal of Heart and Lung Transplantation.

Expert radiologists scored radiologic signs of CTEPH using initial CTPA scans in a blinded fashion. A total of 50 patients with confirmed acute PE were later diagnosed with CTEPH during follow-up while another 50 patients who had sequential echocardiograms performed >2 years after acute PE diagnosis did not show any signs of pulmonary hypertension.

The control index CTPA scans included in the study (n=50) had signs of RV overload. Radiologic parameters for predicting CTEPH were analyzed.

For CTEPH diagnosis, the overall calculated expert reading offered a sensitivity and specificity of 72% (95% CI, 58%-84%) and 94% (95% CI, 83%-99%), respectively. Independent predictors for CTEPH according to the readings included intravascular webs (odds ratio [OR], 48; 95% CI, 13-177); pulmonary artery retraction or dilatation (OR, 18; 95% CI, 6.2-55); and bronchial artery dilatation (OR, 13; 95% CI, 4.0-39). Other predictors were RV hypertrophy (OR, infinite) and interventricular septum flattening (OR, 18; 95% CI, 6.1-55).

Readings that contained ≥3 identified radiologic parameters yielded a sensitivity of 70% (95% CI, 55%-82%), specificity of 96% (95% CI, 86%-100%), and c-statistic of 0.92.

Limitations of the study include its small sample size as well as the inclusion of only patients with CTEPH and PE with RV overload.

Findings from this study “may help in achieving earlier diagnosis and therapeutic implementation in the effort to improve the prognosis of these patients with CTEPH,” the researchers wrote.

Disclosure: This study was supported by an unrestricted grant from Merck Sharp & Dohme.

Reference

Ende-Verhaar YM, Meijboom LJ, Kroft LJM, et al. Usefulness of standard computed tomography pulmonary angiography performed for acute pulmonary embolism for identification of chronic thromboembolic pulmonary hypertension: results of the InShape III study [published online March 15, 2019]. J Heart Lung Transplant. doi:10.1016/j.healun.2019.03.003