EVALUATION OF PULMONARY-ARTERY HISTOPATHOLOGIC FINDINGS IN CONGENITALHEART-DISEASE - AN IN-VITRO STUDY USING INTRAVASCULAR ULTRASOUND IMAGING

Objectives. This study aimed to 1) compare in vitro intravascular ultr asound images of human pulmonary arteries with corresponding histologi c sections, and 2) correlate the relation between intravascular ultras ound findings and Heath-Edwards pathologic grade of pulmonary vascular changes. Background. The pathologic assessment of the pulmonary vascu lar bed is essential for diagnosis and management of congenital heart disease with pulmonary hypertension. Methods. We evaluated and compare d intravascular ultrasound images with histologic findings at identica l sites in 40 pulmonary artery segments from 17 autopsy studies: group 1 = 7 patients with pulmonary hypertension (Heath Edwards grade I to V, 20 segments); group 2 = 10 patients without cardiopulmonary disease (20 segments). Results. In group 2, the pulmonary artery wall echo co nsisted of a single layer. In group 1, I) all segments of pulmonary ar teries from patients with pulmonary hypertension showed a three-layere d appearance; 2) in patients with mild pulmonary hypertension (Heath-E dwards grades I and II), intravascular ultrasound demonstrated increas ed thickness of the echoluscent zone due to medial hypertrophy with no intimal reaction; 3) patients with severe pulmonary hypertension (Hea th Edwards grade III or higher) had intravascular ultrasound findings of increased medial thickness and a bright inner layer from intimal hy perplasia; 4) percent wall thickness derived from intravascular ultras ound showed a significant correlation with that determined by histolog ic examination (r = 0.89, p = 0.0001, n = 20). Conclusions. Changes ob served with intravascular ultrasound imaging correlate well with histo pathologic grade. Thus, intravascular ultrasound may have significant utility in the evaluation of pulmonary vascular morphology in patients with pulmonary hypertension.