ABSTRACT
Aim/Introduction: Chronic thromboembolic pulmonary hypertension (CTEPH) is a difficult entity to diagnose due to its association with other etiologies causing pulmonary hypertension (PHT), mainly cardiological disease. Our aim is to analyse the value of pulmonary perfusion SPECT/CT in the presence of suspected CTEPH and to evaluate its impact on the diagnosis and subsequent therapeutic approach. Material(s) and Method(s): Retrospective series of 108 patients with suspected CTEPH who were performed a lung perfusion SPECT/CT in the presence of perfusion defects on planar images between March 2020-April 2022. Variables such as age, sex, scintigraphic result, other radiological findings, correlation with catheterisation and CT angiography, type of PHT (according to Dana Point Consensus Classification of Pulmonary Hypertension, California 2008) and therapy of choice after scintigraphy were analysed. Result(s): Mean age: 69 +/- 12 years (25-90). 54% women. In 55 patients(51%) CTEPH was ruled out by SPECT/CT(-), although other radiological findings were observed (13% chronic parenchymal pathology/post-COVID-19 infection, 7% cardiomegaly, 5% pleural effusion, 4% infiltrates consistent with COVID-19 infection,2% pulmonary nodule suspicious of malignancy). 6 of the 18 patients with catheterisation(33%) had a pulmonary capillary pressure(PCP) suspicious for CTEPH(<=15mmHg), which was ruled out after negative scintigraphy. In the 53(49%) confirmed CTEPH by SPECT/ CT(+), 28 with other radiological findings(36% chronic pulmonary pathology/post-COVID-19,11% pulmonary nodule suspicious of malignancy,11% infiltrates consistent with COVID-19 infection). 10 of 15 patients(67%) with CT angiography(-). 55% of the patients with catheterisation(11/20) presented with a PCP not suspicious of CTEPH(>=15mmHg), and were finally diagnosed with CTEPH after positive SPECT. In patients without CTEPH after SPECT(-), PHT was classified into the following types:37 with PHT type-II/left heart disease(6 candidates for valve replacement),9 type-III/pulmonary disease and/or hypoxaemia, 5 mixed type-II+III, 2 type-I (1 portal hypertension in cirrhotic patient and 1 scleroderma), 2 type-V (1 obstruction of tumour origin and 1 chronic renal failure). of the patients who were confirmed to have CTEPH, 19(36%) had purely embolic PHT(type-IV), with 5 being candidates for endacterectomy/ angioplasty, and the remaining 34(64%) had mixed PHT(24 type-II+IV, 5 type-III+IV, 5 type-II+III+IV), with 35% being candidates for surgery. Conclusion(s): Lung perfusion SPECT/CT imaging is a very useful test for the classification of pulmonary hypertension leading to better therapeutic management of these patients. The greatest efficiency is seen with a negative result as the embolic origin is excluded with excellent reliability, thus avoiding more aggressive and/or difficult-to-manage therapies. In addition, low-dose CT provides additional information of great clinical relevance.