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The echocardiogram of a 62-year-old woman with a medical history of anti-synthetase syndrome associated with interstitial lung disease (ILD) suggested pulmonary hypertension. An etiological evaluation of pulmonary hypertension was performed. The ventilation/perfusion scan had the aspect of perfusion defects with dissociation. The CT scan showed features of active ILD (basal and subpleural pulmonary infiltration with regular septal line thickening and ground glass-like opacities). After multidisciplinary discussion, the pulmonary hypertension was considered to be secondary to either chronic thromboembolic pulmonary hypertension (CTEPH) and/or ILD. It was decided (i) to initiate an oral anticoagulant (rivaroxaban) and (ii) to initiate intravenous cyclophosphamide plus oral corticosteroids. One year later, while the patient was still taking rivaroxaban, right heart catheterisation showed the persistence of pre-capillary pulmonary hypertension with mean pulmonary arterial pressure of 27 mm Hg, wedge PAP of 11 mm Hg, a cardiac index of 3.2 L/min/m2 and pulmonary vascular resistance of 3.2 Wood units. A ventilation/perfusion scan confirmed mismatched perfusion defects and dual energy CT (DECT) (figure 1A and B) showed a mosaic attenuation pattern predominantly in the left inferior lobe (figure 1C and D) suggestive of CTEPH, but there were no webs, tapering or occlusion of vessels on the CT angiogram. Nevertheless, a systematised perfusion defect of the left inferior lobe was confirmed by non-selective digital subtraction pulmonary angiography (figure 1E and online supplementary video 1). After multidisciplinary discussion, the patient was referred for balloon pulmonary angioplasty treatment.
Supplementary video
Contrary to the ventilation/perfusion scan, DECT and the non-selective digital subtraction pulmonary angiography, the better targeted selective angiography of A8 and A9 segmental branches (figure 2A and online supplementary video 2) did not reveal any flow abnormalities or anatomical lesions typical of CTEPH. Intravascular optical coherence tomography (OCT) confirmed the absence of a CTEPH lesion in these segmental branches (figure 2B). CTEPH was thus excluded, the final diagnosis of pulmonary hypertension secondary to ILD was retained, and anticoagulation was stopped.
Supplementary video
Discussion
In patients with pulmonary hypertension, ventilation/perfusion scans, DECT and CT scans most often identify CTEPH with a high negative predictive value.1 Nevertheless, the remodelling of parenchymal and vascular structures due to ILD may induce perfusion abnormalities similar to those seen in CTEPH and can lead to a misdiagnosis. In the case reported here, non-selective digital subtraction pulmonary angiography was unable to correct the misdiagnosis of CTEPH. In contrast, selective angiography showed normal perfusion. Intravascular OCT is an interesting tool able to detect CTEPH lesions even in the absence of obvious lesions detected by selective angiography2 and is therefore becoming more extensively used to guide treatment for CTEPH.3 In our case, OCT confirmed the absence of an intravascular lesion in the pulmonary arteries suggested by selective angiography. This case highlights the difficulty in making an etiologic diagnosis of pulmonary hypertension in patients with chronic lung disease, and shows the ability of selective angiography and intravascular OCT to make an appropriate diagnosis and thus, treatment.
Acknowledgments
We thank A Foote (Grenoble Alpes University Hospital) for critically editing the manuscript.
Footnotes
Contributors All authors have actively participated in the preparation of the article and have read and approved the text.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement There are no data in this work