Early Diagnostic Features of Left-to-Right Shunt-Induced Pulmonary Arterial Hypertension in Piglets

Background. We aimed to establish early diagnostic characteristics of left-to-right shunt-induced pulmonary arterial hypertension (PAH) in a piglet model. Methods. A shunt-induced PAH in piglets (n = 9) was successfully established by anastomosis of vascular prosthesis from aorta to pulmonary artery with follow-up for 6 months by a number of diagnostic procedures. Results. PAH developed with mean pulmonary arterial pressure [PAP] of 30.2 +/- 6.0 mm Hg immediately after operation and 33.5 +/- 8.7 mm Hg at 3 months after operation with pulmonary vascular resistance increased to 4.0 +/- 0.9 Wood units. There was a weak correlation on systolic PAP between catheterization and echocardiography but the Tei index was significantly correlated to systolic PAP. Magnetic resonance imaging demonstrated that the end-diastolic volume index, systolic volume index, ejection fraction of the ventricle, and ventricular mass index were sensitive indices. Technetium-99m single-photon emission computed tomography indicated increased blood flow in the upper and middle zones of both lungs. Positron emission tomography-computed tomography (PET-CT) demonstrated a higher kilo count (kct) of 18(F-)fluorodeoxyglucose in the right ventricular wall and both chambers at 3 months postoperatively (right ventricular wall: 5,708.3 +/- 428.4 versus 3,965.5 +/- 138.6 preoperatively, p = 0.003; both chambers: 2,963.6 +/- 219.4 versus 1,710.1 +/- 35.4 preoperatively, p < 0.05) as well as at 6 months for both chambers (p < 0.05). Conclusions. In this successful left-to-right shunt-induced PAH model in piglets, sensitive indices including the Tei index, systolic volume index, ejection fraction, ventricular mass index, lung perfusion, and glycometabolism by PET-CT in early PAH are determined. For the first time, we report that glycometabolism by PET-CT is useful in early diagnosis. These indices may be used for the early diagnosis in the left-to-right shunt-induced PAH. (C) 2018 by The Society of Thoracic Surgeons