Background: There have been many cases of pulmonary thromboembolism (PTE) that were not diagnosed in the acute phase and not classified as chronic thromboembolic pulmonary hypertension (CTEPH). The aim of the present study was clarify the clinical characteristics of chronic PTE.
Methods and results: The study subjects were 601 patients (chronic PTE = 92, acute PTE = 456, CTEPH = 53) who were clinically diagnosed before their death. Dyspnea and chest pain, which are frequently found in acute PTE, were found less frequently in chronic PTE. The diagnosis of chronic PTE is often delayed in cases of mild to moderate severity with atypical onset. Chronic heart failure and chronic respiratory failure were most frequent in chronic PTE, and cerebrovascular disease was present in approximately 15% of the cases of chronic PTE. Pulmonary angiography and ventilation lung scan were used least frequently in acute PTE. Heparin and thrombolysis were used most frequently in acute PTE.
Conclusions: Besides the atypical onset and reduced severity, the presence of preexisting diseases may be one of the reasons why the diagnosis for chronic PTE is delayed. The diagnostic and management techniques differ according to the type of PTE.