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Bilateral pulmonary artery stenosis with pulmonary hypertension due to Takayasu’s arteritis, examined using quantitative flow ratio during revascularization


 Therapeutic effect evaluation is based on morphology performed by angiography conventionally. QFR is a new angiography-based tool for vascular assessment of functional severity. We report the first QFR examination in the field of Takayasu's arteritis patient with pulmonary artery stenosis and pulmonary arterial hypertension. It seems simple and practicable during off-line pulmonary artery intervention assessment.

A 56-year-old man presented with a 5-year history of exertional dyspnoea and 6 months of aggravation. The patient had a history of hypertension for 10 years and a smoking history of 30 years, with no other significant history. The patient was first admitted to another hospital and then transferred to the pulmonary vascular disease ward at our hospital due to suspected Takayasu's arteritis. His vital signs were normal, and his blood pressure was equal in both arms. Bruits could be heard in both lung areas (bilateral chest T4 level and back T3 level) and bilaterally over the subclavian arteries. His erythrocyte sedimentation rate (2 mm/h, normal range 0-15 mm/h) and C-reactive protein levels (1.7 mg/L, normal range 0-8 mg/L) were within the normal ranges, and other tests were negative, including immune markers, hepatitis markers, liver and kidney function tests, coagulation tests, and electrolyte tests. Computed tomography (CT) revealed irregular wall-thickening of the ascending aorta ( Figure 1B) and stenosis of the bilateral pulmonary arteries ( Figure 1A, Video 1). Dual-energy CT imaging of both lungs was performed, and chronic thromboembolic pulmonary hypertension was ruled out. Takayasu's arteritis was diagnosed according to the American College of Rheumatology 1990 criteria. The patient met three criteria for Takayasu's arteritis, including development and worsening of fatigue, bruit over the subclavian, and stenosis of bilateral pulmonary arteries. Takayasu's arteritis with pulmonary artery involvement was diagnosed and classified as type V.
Conventional angiography confirmed the CT findings ( Figure 1C and G, Videos 2 and 3). Right heart catheterization revealed an elevated pulmonary arterial pressure of 104/14/41 mmHg (Supplementary material online, Table S1), and a Pul-Stent PAS.M20 (Med-Zenith Medical Scientific Cooperation Limited, Beijing) was implanted into the left pulmonary artery (LPA) to relieve the stenosis ( Figure 1D, Supplementary material online, Video S1). One month later, the patient was readmitted. Right heart catheterization was performed before treatment (Supplementary material online, Table S1). A Pul-Stent PAS.S25 was implanted into the right pulmonary artery (RPA), and the pulmonary pressure dropped to 77/11/31 mmHg after revascularization ( Figure 1H, Supplementary material online, Video S2). Off-line serial quantitative flow ratio (QFR) assessment demonstrated that his QFR value increased from 0.6 to 0.75 after the LPA intervention ( Figure 1E and F) and from 0.1 to 0.89 after the RPA revascularization ( Figure 1I and J). Tadalafil (20 mg/day) and antithrombotic treatment with steroids and azathioprine were prescribed following a consultation with a rheumatologist. There is no evidence regarding which target drugs are beneficial for pulmonary hypertension due to pulmonary arteritis. We prescribed tadalafil based on the patient's choice, according to his economic status. The patient was discharged from the hospital with a good general condition and is now on regular follow-up, with complete recovery of dyspnoea.
Pulmonary artery stenosis has been recognized as a result of pulmonary artery involvement in Takayasu's arteritis, and pulmonary hypertension may be a complication. Patients with Takayasu's arteritis complicated with pulmonary hypertension typically present poor prognoses. Interventional therapy has been reported to improve the haemodynamics of patients with pulmonary hypertension due to pulmonary artery stenosis caused by Takayasu's arteritis. 1 A proper intervention strategy is crucial to ensure the success of the procedure. Therapeutic effect evaluation is based on morphology and is conventionally performed by angiography. QFR is a new angiography-based tool for vascular assessment of functional severity and has become the gold standard for the diagnosis of intermediate coronary stenosis, according to current society guidelines. 2,3 To our knowledge, this is the first QFR examination to be reported for a Pulmonary artery (PA) patient with pulmonary artery stenosis and pulmonary arterial hypertension. The procedure seems simple and practicable for offline pulmonary artery intervention assessment.

Supplementary material
Supplementary material is available at European Heart Journal -Case Reports online.

Consent:
The authors confirm that written consent for submission and publication of this case report including images and associated text has been obtained from the patients in line with COPE guidance.