INTRODUCTION: We present the first reported case of combined medical and interventional therapies for the treatment of PH associated with Takayasu's Arteritis (TA).
CASE PRESENTATION: A 49 year-old female presented with a three-year history of progressive shortness of breath, fatigue and exertional chest discomfort. She had TA for 18 years; although, the disease had been in clinical remission for 8 years; she was taking no medications. Computed tomography pulmonary angiogram demonstrated a 2.2 cm stenosis of right pulmonary artery (RPA) and focal stenosis of left pulmonary artery with distal aneurysmal dilatation. Right and left heart catheterization demonstrated severe pulmonary hypertension (PASP 150mmHg, PADP 41 mmHg, mean PA pressure 80 mmHg and pulmonary vascular resistance [PVR]) 1600 dyn s/cm5), and single vessel coronary artery disease. Due to the severity of the PH, epoprostenol was begun. Despite an increasing dose of epoprostenol during the subsequent 4 years, evidence of right heart dysfunction ensued. Repeat right heart catheterization demonstrated mild improvement in pulmonary artery pressure; but the PVR remained markedly elevated (1012 dyn sec/cm 5) and the cardiac index had decreased. A pulmonary arteriogram demonstrated that the 2.2 cm stenosis of the main RPA had a peak trans-stenotic pressure gradient of 92mm Hg (mean gradient 42mm Hg). The PH regimen was intensified by addition of sildenafil; but, she could not tolerate this and there were increased admissions for volume overload. Evidence of right heart dysfunction progressed despite increased epoprostenol and diuretics: she developed ascites, congestive hepatopathy, progressive renal dysfunction and was only able to walk 25 feet (WHO Functional Class IIIb-IV). At this point, the large stenosis of the RPA was successfully stented and the peak trans-stenotic gradient decreased to 35mm Hg. The increased blood flow to the chronically under-perfused right lung (estimated by Poiseuille's Law as 33 times greater), did result in transient pulmonary edema of the right lung. However, within one week, the diuretic dose was decreased; renal function, BNP and liver function had normalized, oxygenation improved, and she was able to walk >100 feet. At 13 month follow-up post-procedure: she can now walk >400ft (WHO Functional Class II); there are no overt signs of right heart failure; however, there has been no significant change in RVSP by echocardiogram.
DISCUSSIONS: In patients with TA, 45-80% have an abnormal lung scan and 30-74% an abnormal pulmonary angiography.(1) The natural history of pulmonary involvement in TA is unclear; however it does appear that many patients with pulmonary involvement develop PH. As in this patient, PH associated with TA can be severe and is associated with a poorer prognosis. The etiology of the PH is likely multi-factorial and not simply related to mechanical obstruction of the pulmonary vascular bed by stenoses due to the arteritis. In the current case, the patient initially improved with systemic prostanoid therapy (epoprostenol). Previous reports of medical therapy of PH associated with TA have had a much shorter follow-up period. Not unexpectedly, due to the extensive and severe RPA stenosis, the response to medical therapy in this patient was limited. Relieving the extensive obstruction to the right PA, although technically challenging, resulted in significant clinical improvement and a marked decrease in signs of right ventricular dysfunction.
CONCLUSION: Pulmonary arterial involvement in TA is not uncommon and results in significant morbidity. We report the first case of PH associated with TA successfully treated initially with long-term epoprostenol, and, when the effectiveness of medical therapy eventually waned, was complimented by endovascular stenting of the severe RPA stenosis.
DISCLOSURE: Praveen Govender, No Financial Disclosure Information; No Product/Research Disclosure Information