Abstract: AIM:To explore the relationship between the percentage pulmonary vascular area ［(EA(%)］ by dual-source computed tomography (CT) and the pulmonary vascular micromorphological indexes in patients with congenital heart disease complicated by pulmonary hypertension (PH). METHODS: Ninety-two patients with congenital heart disease were randomly selected and divided into three groups according to the extent of PH: No-PH group (29 patients) with preoperative mean pulmonary artery pressure (MPAP) <20mmHg, PH group (55 patients) with preoperative MPAP >20mmHg and <80mmHg, and cyanosis group (eight patients) with preoperative MPAP >90 mmHg. All patients had dual-source CT before surgery and EA(%) was calculated. Pulmonary vascular micromophological indexes were measured according to Heath-Edwards pathological grading. RESULTS: Eleven patients were grade I, 16 patients were grade Ⅱ, 19 patients were grade Ⅲ, 9 patients were grade Ⅳ, and 8 patients were grade V. With the increase of the PH grade, the EA(%) significantly decreased but the WT(%) and the WA(%) increased (P<0.01). CONCLUSION: The EA(%) and the pulmonary vascular pathological changes are related in patients with congenital heart disease complicated by PH and the EA(%) is helpful in evaluating the extent of PH.