Abstract
ObjectiveThe diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) is a major challenge as it is a curable cause of pulmonary hypertension (PH). Ventilation/Perfusion (V/Q) lung scintigraphy is the imaging modality of choice for the screening of CTEPH. However, there is no consensus on the criteria to use for interpretation. The aim of this study was to assess the accuracy of various interpretation criteria of planar V/Q scintigraphy for the screening of CTEPH in patients with PH.MethodsThe eligible study population consisted of consecutive patients with newly diagnosed PH in the Brest University Hospital, France. Final diagnosis (CTEPH or non-CTEPH) was established in a referential center on the management of PH, based on the ESC/ERS guidelines and a minimum follow-up of 3 years. A retrospective central review of planar V/Q scintigraphy was performed by three nuclear physicians blinded to clinical findings and to final diagnosis. The number, extent (sub-segmental or segmental) and type (matched or mismatched) of perfusion defects were reported. Sensitivity and specificity were evaluated for various criteria based on the number of mismatched perfusion defects and the number of perfusion defects (regardless of ventilation). Receiver operating characteristic (ROC) curves were generated and areas under the curve (AUC) were calculated for both.ResultsA total of 226 patients with newly diagnosed PH were analyzed. Fifty six (24.8%) were diagnosed with CTEPH while 170 patients (75.2%) were diagnosed with non-CTEPH. The optimal threshold was 2.5 segmental mismatched perfusion defects, providing a sensitivity of 100 % (95% CI 93.6–100%) and a specificity of 94.7% (95%CI 90.3–97.2%). Lower diagnostic cut-offs of mismatched perfusion defects provided similar sensitivity but lower specificity. Ninety five percent of patients with CTEPH had more than 4 segmental mismatched defects. An interpretation only based on perfusion provided similar sensitivity but a specificity of 81.8% (95%CI 75.3–86.9%).ConclusionOur study confirmed the high diagnostic performance of planar V/Q scintigraphy for the screening of CTEPH in patients with PH. The optimal diagnostic cut-off for interpretation was 2.5 segmental mismatched perfusion defects. An interpretation only based on perfusion defects provided similar sensitivity but lower specificity.
Highlights
Chronic Thromboembolic Pulmonary Hypertension (CTEPH) is a rare complication of acute pulmonary embolism (PE) leading to severe right ventricular failure and death in the absence of treatment [1]
The diagnosis of precapillary PH was established according to the 2015 guidelines [mean Pulmonary Artery Pressure (mPAP) ≥ 25 mmHg and pulmonary artery wedge pressure (PAWP) ≤ 15 mmHg measured by right heart catheterization (RHC)] [18]
Among those 288 patients, 62 were excluded from the present study for the following reasons: 5 patients had a well-established diagnosis of a PH attributable to left heart disease with a post-capillary PH on RHC; 19 had V/Q SPECT imaging; three had a perfusion-only scan; images
Summary
Chronic Thromboembolic Pulmonary Hypertension (CTEPH) is a rare complication of acute pulmonary embolism (PE) leading to severe right ventricular failure and death in the absence of treatment [1]. CTEPH is characterized by the presence of macroscopic thromboembolic lesions in the proximal or distal pulmonary arteries and microscopic pulmonary vasculopathy, which obstruct blood flow and increases pressure in the pulmonary arteries [2]. Diagnosing CTEPH is a major diagnostic challenge. The estimated 5-years survival of patients with CTEPH is poor, around 30% in patients with a mean Pulmonary Artery Pressure (mPAP) >40 mmHg [5, 6]. In contrast with other groups of PH, CTEPH is potentially curable thanks to various treatment modalities including surgery, balloon pulmonary angioplasty and medical therapy [7–10]
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