Introduction: Chronic thromboembolic pulmonary hypertension (CTEPH) is a curable and partially preventable complication, with a substantial incidence, leading to severe morbidity and mortality. The aim of the present study was to find out the incidence of CTEPH secondary to acute pulmonary thromboembolism (PTE) using non-invasive procedures such as ventilation/perfusion (V/Q) scintigraphy and pulmonary multidetector CT (MDCT) angiography in determining the diagnosis of CTEPH.
Materials and methods: The study included a total of 99 patients diagnosed with initial PTE between January 2010 and December 2012. The patients who received anticoagulant therapy at least for three months underwent transthoracic echocardiography (TTE) (n= 85). Thirty one patients with a SPAP value > 30 mmHg and/or an evidence of right ventricular dysfunction in TTE underwent MDCT pulmonary angiography and V/Q scintigraphy. The patients with an evidence of residual chronic thromboembolic signs in MDCT pulmonary angiography and/or segmental perfusion defect(s) in V/Q scintigraphy underwent right heart catheterization (RHC) (n= 7). The mean PAP was measured, and a vasoreactivity test was performed. During RHC, a non-contrast medium was delivered to the pulmonary arteries for pulmonary arteriography imaging.
Results: Among patients diagnosed with PTE, 44 were male and 55 were female. The mean age was 60 ± 17 years. Of these patients, 63.6% had history of at least one additional disease and at least one risk factor for PTE. During diagnosis, 24 subjects were considered having massive, 61 submassive and 14 non-massive PTE. Nineteen (19.1%) patients received thrombolythic therapy. Other 80 (80.8%) patients received standard anticoagulant therapy with an INR value within the therapeutic range. In 79.8% of patients, thromboembolism was bilateral, and it was unilateral in 21.8%. After a minimum of 1 year, and maximum of 2 years follow up five subjects (5.5%) were diagnosed with CTEPH. The univariate analysis showed no association between the development of CTEPH and factors like; age, etiologic risk factors for PTE, receiving thrombolytic treatment, prevalence and type of PTE.
Conclusion: Potentially preventabl complication of pulmonary embolism; CTEPH, had a substantial incidence during follow-up.