Does pulmonary embolism guideline increase the pulmonary vascular obstruction index and help to elucidate the severity of pulmonary embolism?

According to Chinese Thoracic Society (CTS) guidelines, patients with pulmonary embolism (PE) can be stratified into low-risk, intermediate-low, intermediate-high, and high-risk groups based on the severity and comorbidity assessment. For low-risk PE patients, anticoagulant therapy can be given in outpatient department. Patients at high risk for PE may require thrombolytic therapy; however, this risk stratification is not included in comparing the pulmonary vascular obstruction index (PVOI) assessment. In practice, this severity and comorbidity assessment often leads people to believe that PE severity is positively correlated with PVOI assessment, i.e., the larger the thrombus, the higher the risk stratification, and the smaller the thrombus, the lower the risk stratification. Herein, we investigated the relationship between PVOI and risk stratification and prognosis in PE patients. We found that although some patients had a greater PVOI, they were low-risk patients according to the PE severity. Moreover, even though some patients had small PVOI, they were intermediate-risk and high-risk patients, and their PVOI did not correlate with the severity of PE. Therefore, we recommend that the PE guidelines add a classification of the degree of thrombus occlusion to the risk group, as this could reduce misconceptions about the severity and comorbidity assessment of PE.