Assessment of Operability by Means of CTPA and Perfusion SPECT in Patients with Chronic Thromboembolic Pulmonary Hypertension

Objective: Chronic thromboembolic pulmonary hypertension (CTEPH) is curable with pulmonary endarterectomy (PEA). The criteria for identification of PEA-amenable patients need to be standardized.The aim of this study was to evaluate the value of rigidly registered CT pulmonary angiography (CTPA) and perfusion SPECT in differentiating between operable and non-operable patients. Methods: 49 patients with CTEPH (21 men, 58±13 years) were evaluated for PEA by interdisciplinary board using available diagnostic information and served as the gold standard.SPECT was evaluated by a lobe based visually assessed perfusion score ranging from 0 [no perfusion] to 1 [normal perfusion]),after which the percentage of vascular obstruction (PVO) was calculated: PVO = [1 – Perfusion score] × 100. By CTPA, the vascular obstruction index (OI) of central, peripheral, and global PA bed and diameters of large vessels(pulmonary artery (PA), aorta (Ao) and PA/Ao) was determined. In angiography PA pressure (PAP), PA resistance (PVR) and wedge pressure (PCm) were determined. Receiver operating characteristics (ROC) analysis was performed. Results: Mean PAP, PVR and PCm was 48±11 mmHg, 878±461dynes sec cm -5 , and 11±5 mmHg. 30 patients were chosen as candidates for PEA. Hemodynamic values were not able to differentiate between operable and non-operable patients. PVO and central OI separated PEA-amenable patients (both p Conclusion: An accurate interpretation of rigidly registered CTPA and perfusion SPECT may contribute to stratification of operability in patients with CTEPH.